Femoral Artery Catheterization Research Articles

Deletion of Irisin Mitigates HDAC4 Inhibitor-Elicited Protective Effect in Hemorrhage

Introduction: Histone deacetylate inhibition contributes critically to modulating insulin resistance and cardiovascular function. It remains unknown whether inhibition of specific HDAC isoform 4 could improve cardiac function and attenuates inflammatory response and whether HDAC4 inhibition-induced protection is related to irisin. The objective of this study is to investigate whether HDAC4 inhibition induced protective effect against hemorrhage-induced detrimental effects would be diminished by deletion of irisin. Method: Irisin knockout (irisin−/−) mice was generated by using the CRISPR/Cas-9 genome-editing system. Hemorrhage was induced in mice by achieving a mean arterial blood pressure of 35-45 mmHg for one hour, followed by two hours of resuscitation. Experimental groups were divided as followings: I) Wild type (WT)+Hemorrhage (control) (N=7): WT mice were subjected to hemorrhage for 60 minutes followed by resuscitation; II) NVS-HD-1+Hemorrhage (n=7): The same as the group I except that NVS-HD1, a selective HDAC inhibitor (3mg/kg) was infused during resuscitation; III) Irisin −/− +Hemorrhage (n=6): Irisin −/− mice underwent hemorrhage and resuscitation; IV) NVS-HD-1 + Irisin−/−+Hemorrhage (n=6): The same as the groups III except that NVS-HD-1 was given to Irisin −/− during resuscitation. Myocardial function and hemodynamics were assessed using echocardiography and femoral artery catheterization, respectively. Cytokine releases from serum were measured using Enzyme-linked immunosorbent assay (ELISA). Histological assessment was performed to determine tissue damage in both myocardium and skeletal muscles. TUNEL was carried out to assess apoptotic signal in tissues. Results: As compared to control group, HDAC4 inhibitor significantly improved the cardiac function and recovery of hemodynamics, which was associated with the decreased release of IL6 and TNF-α in hemorrhage. The infiltration of inflammatory cells and TUNEL positive apoptosis in muscles were mitigated by inhibition of HDAC4. However, HDAC4 inhibitor-induced myocardial protection and suppression of inflammation against hemorrhage was lost by genetic deletion of irisin. Conclusion: Selective inhibition of HDAC4 produced protective effects with an improvement in myocardial function and attenuation of inflammation against hemorrhage, which is dependent on irisin. The work is supported by the National Institute of General Medical Sciences (R01GM 141339), United States; the National Heart, Lung, and Blood Institute Grants (R01 HL089405), United States. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Deletion of irisin exacerbate cardiac dysfunction and increase inflammatory response in hemorrhage

Introduction: Irisin plays an important role in regulating tissue stress, cardiac function, and inflammation. The objective of this study is to investigate whether deletion of irisin would exacerbate hemorrhage induced cardiac depression and inflammatory response. Method: Irisin knockout mice was generated by using the CRISPR/Cas-9 genome-editing system. Hemorrhage was induced in mice by achieving a mean arterial blood pressure of 35-45 mmHg for one hour, followed by two hours of resuscitation. Experimental groups were divided as followings: I) WT+Hemorrhage (control, n=6): WT mice were subjected to hemorrhage for 60 minutes followed by resuscitation; II) Irisin −/− +Hemorrhage (n=6): Irisin −/− mice underwent hemorrhage and resuscitation; III) WT +Hemorrhage+Irisin (n=8): The same as the group I except that irisin (50ng/kg) was infused during resuscitation; IV) Irisin −/− +Hemorrhage+ Irisin (n=7): The same as the groups III except that Irisin −/− was used. Cardiac function and hemodynamics were measured using echocardiography and femoral artery catheterization. Systemic cytokine releases were measured using Enzyme-linked immunosorbent assay (ELISA). Histological analyses were used to determine tissue damage in myocardium and skeletal muscles. TUNEL was carried out to assess apoptosis in tissues. Results: As compared to wild type mice, irisin knockout mice attenuated the cardiac function and recovery of hemodynamics, which was associated with the increased release of IL6 and TNF-α in hemorrhage. The infiltration of inflammatory cells and TUNEL positive apoptosis in muscles were increased by deletion of irisin. Irisin treatment demonstrated the profound protection against hemorrhage-induced detrimental effect as compared to control. Furthermore, re-infusion of irisin into irisin-knockout mice rescued mitigated the detrimental effect in hemorrhage by deletion of irisin. Conclusion. Deletion of irisin exacerbate hemorrhage induced cardiac depression and inflammatory response, suggesting critical protection of irisin in modulating hemorrhage. National Institute of General MedicalSciences (R01GM 141339); National Heart, Lung, andBlood Institute Grants (R01 HL089405). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Unraveling a Novel Mechanism of Altered Glomerular Hemodynamics in Pre-diabetic Obesity

Background: In pre-diabetic obesity, disrupted glomerular autoregulation leads to increased glomerular capillary pressure and renal blood flow, causing potential barotrauma-induced glomerular damage. A decrease in Afferent arteriole ( Af-Art) resistance causes higher glomerular capillary pressure but the underlying mechanism behind this, specifically in pre-diabetic obesity, remains unclear. Hyperinsulinemia is common in pre-diabetic obesity, but its role in reducing Af-Art resistance in the kidneys is unknown. Kidney blood flow is auto-regulated by vasoconstriction via tubuloglomerular feedback (TGF) and vasodilation through the Distal convoluted tubule-2/connecting tubule (DCT-2/CNT) mechanism. Our earlier studies indicate increased Af-Art dilation in pre-diabetic obese rats through the DCT-2/CNT mechanism without affecting TGF. This DCT-2/CNT induced Af-Art dilation requires initiation from epithelial sodium channels (ENaC) present at this tubular segment and interestingly insulin is a known ENaC activator. Hypothesis: We hypothesize that in the context of pre-diabetic obesity, hyperinsulinemia contributes to an increase in renal cortical blood flow (CBF) by increasing DCT-2/CNT-induced Af-Art dilation, subsequently leading to glomerular injury. Methods: We assessed the effects of insulin on Af-Art dilation by perfusing juxtaposed DCT-2/CNT segments with insulin in normal rabbits. Contribution of DCT-2/CNT induced Af-Art dilation was measured by co-administration of the ENaC blocker benzamil. To study hyperinsulinemia's role in an in-vivo setting without altering blood glucose levels, we used a hyperinsulinemic-euglycemic (HI-EUG) clamp in obese rats with intravenous (IV) glucose and insulin infusions. Renal CBF and blood pressure were monitored using a laser Doppler probe and femoral artery catheter, respectively, both with and without benzamil administration (400 μg/kg, IV). To evaluate insulin's potential role in causation of renal damage, we infused insulin directly into one kidney of lean rats for 6 weeks via a renal sub-capsular catheter, with the contralateral kidney serving as control. Glomerular basement membrane (GBM) thickness, a marker of renal damage, was measured via electron microscopy. Untargeted lipidomic analysis of the renal cortex was performed to identify potential renal damage pathways in insulin infused kidneys. Results: Insulin perfusion in rabbits' DCT-2/CNT potentiated the dilation of adherent Af-Art compared to control infusions with artificial tubular fluid. ENaC inhibition reversed the insulin-induced Af-Art dilation, confirming that insulin increases Af-Art dilation through the ENaC-initiated DCT-2/CNT mechanism. In obese rats, insulin delivery using a HI-EUG clamp resulted in a significant 20.8±4.9% increase in CBF, which was negated by the administration of the ENaC blocker benzamil, indicating the potential involvement of DCT-2/CNT-mediated vasodilation. Neither the HI-EUG clamp nor benzamil infusion affected blood pressure. Additionally, continuous direct insulin infusion into the kidneys of lean rats led to an increase in glomerular basement membrane (GBM) thickness and ceramide accumulation in the renal cortex, both indicative of renal damage. Conclusion: Our study demonstrates that insulin directly augments DCT-2/CNT-mediated Af-Art dilation and increases renal cortical blood flow in obese rats. Chronic renal insulin infusion led to structural changes and damage markers in the kidney, independent of blood glucose and blood pressure levels. Henry Ford Health System Internal Funding. Pilot and Feasibility grant from southeast center for integrated metabolomics. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

NADPH Oxidase 4 Knockout in Dahl Salt-Sensitive Rats Impacts Kidney O2 Consumption and UCP2 Responses to a High Salt Diet

Rationale: The effects of a high salt (HS) diet upon renal metabolism and O2 utilization have not been extensively studied and there is a significant gap in our understanding of the role of oxidative stress in the effciency of energy production and substrate metabolism. The present study compared the effects of a HS diet (4% NaCl) on changes in O2 consumption and transcriptomic profiles in Dahl salt-sensitive (SS) rats to SS rats with a global knockout of NADPH oxidase 4 (NOX4) gene (SS Nox4−/−). Methods: Male SS (n=9) and SS Nox4−/− (n=10) rats were fed a 0.4% NaCl (LS) diet. At 7-8 weeks of age, the rats were implanted with a renal artery ultrasonic flow probe (Transonic) together with a femoral arterial catheter and a renal venous catheter. Renal blood flow (RBF) and mean arterial pressure (MAP) were measured continuously (24/7) and arterial (A) and renal venous (Vr) blood was sampled intermittently when rats were fed the LS and on days 7, 14, and 21 after switching to the HS diet. A and Vr blood O2 content was immediately measured by radiometer. From separate groups of rats subjected to the same protocol, the renal cortical tissue (Cx) and outer medulla (OM) were removed for mRNAseq analysis (Novogene, Inc). Results: When switching to the HS diet, the average 24-hour MAP of SS rats rose from 122 ± 2 to 140 ± 2 on HS7 to 164 ± 5 mmHg by HS21. In contrast, MAP in SS Nox4−/− rats increased from 121 ± 2 at LS to 132 ± 1 at HS7 to 152 ± 3 mmHg at HS21 (p<0.05, compared to SS). RBF, normalized by changes of kidney weights obtained in another group of SS and SS Nox4−/− rats fed the same HS diet, SS rats exhibited a significant reduction of RBF over the 3 weeks of the HS diet averaging LS 7.2 ± 0.6, HS7 5.1 ± 0.5 and HS21 4.6 ± 0.7 mL/min/g kidney weight (gkw). This reduction of RBF was not observed in SS Nox4−/− rats (LS 6.8 ± 0.8, HS7 6.6 ± 0.6, HS21 6.0 ± 0.6 mL/min/gkw). The kidney O2 extraction ratio at LS tended to be lower in SS Nox4−/− (11.2 ± 1.7%) compared to SS (14.0 ± 1.1%) (p=0.10). When switched to the HS diet, O2 extraction was significantly reduced in the SS Nox4−/− rats reaching 8.3 ± 1.0% at HS21 (p<0.05), while it did not change significantly in SS (12.7 ± 1.4%) at HS21. Notably, as determined by RNAseq analysis, Ucp2 expression in cortical tissue was significantly greater in SS fed HS than in SS Nox4−/−rats at HS21 . A gene enrichment analysis of the mRNAseq cortical tissue data (GSEA-KEGG pathways) focused on metabolic pathways indicated that knockout of Nox4 resulted in reduced expression of linoleic acid, lysine, and histidine metabolism pathways at LS when compared to SS. Those differences were not observed after HS feeding. However, upregulation of oxidative phosphorylation pathway was observed at HS21 in SS Nox4−/− when compared to SS rats. In the OM, a greater expression of genes associated with fatty acid degradation and carbon metabolism was observed in SS Nox4−/− rats when fed LS which was observed also at HS21. Conclusion: The preliminary results of this study suggest that reduced extraction of O2 in the SS Nox4−/− rats compared to SS rats may be partially explained by the differential response of Ucp2 to salt. Further studies are needed to determine whether the effciency of ATP production is enhanced in SS Nox4−/− as consequence of reduction of reactive oxygen species (e.g., H2O2) and the related downstream pathways such as phosphorylation of mTORC1. R01 HL151587, AHA 23POST1008714. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Acute Intermittent Hypoxia Induces Chemoreflex-Independent Sympathetic Plasticity and Improves Cardiovascular Function in a Rodent Model of Spinal Cord Injury

Background: Cardiovascular complications are one of the leading causes of morbidity and mortality in people with spinal cord injury (SCI). Activation of spinal sympathetic circuitry is critical to offset cardiovascular dysregulation and disease in those with high-level SCI. Acute intermittent hypoxia (AIH) elicits plasticity (i.e., a gradual increase in nerve activity post-AIH exposure) in phrenic and non-phrenic spinal motor circuitry and improves motor function — yet the cardiovascular benefits of AIH after SCI are largely unexplored. Aims: Determine mechanisms (Aim 1) and potential benefits (Aim 2) of AIH-induced sympathetic plasticity post-SCI. Hypothesis: We hypothesized that AIH elicits chemoreflex-dependent sympathetic plasticity and improves cardiovascular function in rats with SCI. Methods: For Aim 1, 40 adult (10-12 weeks) male Wistar rats were subjected to a spinal cord contusion injury (T3, 300 kdyn) and randomly assigned to 5 groups of 8 each: AIH alone, AIH after carotid body denervation (CBX, no peripheral chemoreflex), time control with no intervention (TC), simulated hemorrhage (to mimic AIH-induced hypotension), and AIH plus phenylephrine (to prevent hypotension during hypoxic episodes). Two weeks post-SCI recovery, rats were anesthetized with urethane (~2.1g.kg−1 i.v.) and underwent femoral venous and arterial catheterizations to monitor blood pressure (BP), sample arterial blood gases, and enable intravenous fluid and drug delivery. Additionally, splanchnic sympathetic nerve activity (sSNA) was recorded using a suction electrode at baseline and for up to 90-min following each experimental paradigm. AIH consisted of 10 x 1 min episodes of FiO2 = 0.1 (balanced N2) interspersed with 2 min of FiO2 = 1. Hexamethonium bromide (30 mg.kg−1) was infused to subtract noise levels from each recording, after which rats were euthanized with chloral hydrate. For Aim 2, 19 additional rats were subjected to the same injury model and time post-injury and allocated to 2 groups: AIH ( n = 11) and TC ( n = 8). These rats were instrumented with left-ventricular (LV) and arterial catheters and assessed simultaneously for cardiac and peripheral hemodynamic function at baseline and 90-min post-AIH/TC. Results: Aim 1) When expressed as % change from baseline, sSNA increased at 90-min post-treatment in AIH (93±67%, P = 0.02) and CBX (193±182%, P < 0.001), but not TC rats (50±45%, P = 0.40). Preventing BP reduction during hypoxic episodes with i.v. phenylephrine blocked the increase in sSNA 90-min post-AIH (12±66%, P > 0.99). Mimicking the AIH-induced BP reduction with simulated hemorrhage (10 x 1-min BP reductions of ~20-25 mmHg equal to those during AIH, interspersed by 2-min of euvolemia), increased sSNA 90-min post-intervention (106±86%, P = 0.01). Aim 2) The changes in maximal LV pressure (AIH = 11±8 mmHg vs. TC = 2±5 mmHg, P = 0.05) and mean arterial pressure (AIH = 8±7 mmHg vs. TC = 0±4 mmHg, P = 0.05) were greater at 90-min post-AIH treatment. Conclusions: We conclude that AIH elicits sympathetic plasticity and improves cardiovascular function post-SCI. Since AIH-induced sympathetic plasticity remains in the presence of a bilateral CBX, is replicated by episodic simulated hemorrhage, and is blocked by phenylephrine, AIH-induced sympathetic plasticity is independent of carotid (peripheral) chemoreflex activation, and is closely linked to episodic hypotension. We suggest that AIH-induced sympathetic plasticity arises from episodic reductions in spinal/medullary cardiovascular centers blood flow (and oxygen delivery) post-SCI. International Spinal Research Trust and Natural Sciences, Engineering Research Council of Canada, International Collaboration on Repair Discoveries. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Metformin as an alternative therapeutic intervention in hemorrhagic shock

Hemorrhagic shock (HS) continues to significantly contribute to civilian and military mortality, underscoring the critical need for new resuscitation strategies. Recent discussions have emphasized the pivotal role of impaired oxygen delivery and cellular metabolism in exacerbating HS-related damage. Metformin, a well-established diabetes medication, exhibits promising potential to enhance cellular metabolism and activate pathways linked to improved oxygen uptake, thereby optimizing cellular energy management. Thus, this study aimed to assess metformin's effcacy in ameliorating outcomes in animals subjected to HS. To achieve this, Wistar rats were surgically prepared with femoral artery and vein catheters. HS was induced by controlled blood withdrawal to maintain a mean arterial pressure (MAP) within the range of 35-40 mmHg for 90 minutes. Throughout the protocol, blood pressure (BP) and heart rate (HR) were assessed. The animals were divided into two groups: Lactated Ringer's solution (LR) and LR treated with Metformin (Met). Metformin was administered in three bolus injections: at the start of resuscitation (10mg), 45 minutes into resuscitation (5mg), and 90 minutes into resuscitation (5mg). After 120 minutes, the animals were euthanized, and blood samples were collected for subsequent analysis, including metabolomic profiling of the tricarboxylic acid (TCA) cycle, amino acids, and lipids. Additionally, trypsin-like enzyme activity in the plasma and markers of brain injury were evaluated. Animals treated with Met showed significantly higher systolic blood pressure after resuscitation (LR: 74±5 mmHg vs. LR+Met: 94±3 mmHg) with no significant changes in HR observed. Brain injury markers such as GFAP (Glial fibrillary acidic protein), S100B (astrocytic protein specific to the central nervous system), Tau (microtubule-associated protein), and NFL (axonal protein neurofilament light) were assessed. Animals reperfused with LR and treated with Met displayed a 22% reduction in GFAP levels compared to those reperfused with LR alone, while other markers remained unchanged. Met treatment also led to a reduction in plasmatic metabolites, including Lactate (30%), Succinate (24%), and Fumarate (22%), along with an increase in Citrate (23%) and α-ketoglutarate (24%)—all constituents of the TCA cycle. Additionally, an increase in amino acid metabolites and a decrease in lipid metabolites were observed. Recent research has suggested that HS results in elevated levels of trypsin-like enzymes in the plasma and that inhibiting these enzymes might improve outcomes during resuscitation. Our study revealed that treatment with Met reduced approximately 60% of trypsin-like enzyme activity in the plasma compared to the LR-only group. In conclusion, our study demonstrates that Met, when administered in conjunction with LR as a resuscitation solution, significantly enhances post-resuscitation BP compared to LR alone. This improved outcome may be associated with alterations in the TCA cycle and the inhibition of trypsin-like enzyme activity. However, further investigations are necessary to elucidate the precise role of these changes in the observed enhancements within this experimental model. This work was supported by National Institutes of Health grant R01HL162120. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Mitochondrial peptides derived from exercising skeletal muscle increase oxidative stress in microvascular endothelial cells

Introduction: Mitochondria-derived peptides are newly discovered small bioactive peptides thought to communicate metabolic status to other cells. Two such peptides, MOTS-c and Humanin, have been shown to have particularly strong local and systemic regulatory effects on metabolism and oxidative stress in tissues, but their effect specifically on vascular endothelial cells remains unclear. Furthermore, it has been proposed that skeletal muscle is a source of MOTS-c and humanin during exercise but this has not been directly shown. Methods: In seven healthy young males, muscle interstitial fluid was collected from microdialysis probes in the thigh muscle, blood was drawn from femoral arterial and venous catheters and thigh muscle biopsies were obtained before and after one acute bout of exercise. In addition, muscle biopsies were obtained before and after 14 days of leg exercise training. Samples were analysed for MOTS-c, Humanin protein and mRNA. To test the effect of MOTS-c on the microvasculature, human endothelial cells derived from the muscle biopsies were incubated for three days with MOTS-c and analysed for mitochondrial respiration and formation of reactive oxygen species (ROS). Furthermore, mice were injected with MOTS-c for 4-weeks to investigate the in-vivo effect of vessels and microvascular endothelial cells. Data was analyzed by linear mixed models performed with R. Results: Acute exercise resulted in an 88% and 55% ( p<0.001) increase in MOTS-c and humanin concentration, respectively, in muscle dialysate, with no effect on the femoral arterial-venous plasma concentration differences. Both MOTS-c and humanin mRNA levels increased (by 20 and 26%; p<0.05) after acute exercise and were 43% and 35% ( p<0.05) higher, respectively, after 14 days of training. A period of MOTS-c treatment of endothelial cells increased mitochondrial respiration and ROS formation by 3-fold and 5-fold, respectively ( p<0.01). Muscle derived endothelial cells from mice injected for 4-weeks presented a similar mitochondrial respiration but a 4-fold ( p<0.05) higher ROS emission. Conclusion: interstitium in response to exercise, muscle is not a likely source of these peptides in plasma. Our data from in vitro and in vivo experiments suggest that treatment with MOTS-c does not influence endothelial metabolism but leads to increased oxidative stress in microvascular endothelial cells. The funding by Novo Nordisk Foundation (application number: 0070369) is gratefully acknowledged. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Insulin regulation of regional lipolysis in upper-body obese and lean humans.

Upper-body obesity (UBO) results in insulin resistance with regards to free fatty acid (FFA) release; how this differs by fat depot and sex between adults with UBO and lean adults is unknown. We tested the hypothesis that insulin suppression of FFA release from the splanchnic bed, leg fat, and upper-body nonsplanchnic (UBNS) adipose tissue would be impaired in UBO. Fourteen volunteers with UBO (7 men and 7 women) and 14 healthy volunteers with normal weight (7 men and 7 women) participated in studies that included femoral artery, femoral vein, and hepatic vein catheterization. We then measured leg and splanchnic plasma flow as well as FFA kinetics (using isotopic tracers) under overnight fasting as well as low- and high-dose insulin infusion using the insulin clamp technique. We found the expected insulin resistance in UBO; the most quantitatively important difference between adults with UBO and lean adults was greater FFA release from UBNS adipose tissue when plasma insulin concentrations were in the postprandial, physiological range. There were obesity, but not sex, differences in the regulation of splanchnic FFA release and sex differences in the regulation of leg FFA release. Reversing the defects in insulin-regulated UBNS adipose tissue FFA release would have the greatest effect on systemic FFA abnormalities in UBO. These studies were supported by the US Public Health Service (grants DK45343 and DK40484), the Novo Nordic Foundation (grant NNF18OC0031804 and NNF16OC0021406), and the Independent Research Fund Denmark (grant 8020-00420B).

388 The First Endovascular Rat Glioma Model for Pre-clinical Evaluation of Intra-arterial Therapeutics

INTRODUCTION: Several translational animal models have been described assessing intra-arterial (IA) treatments for malignant gliomas. We describe the first endovascular animal model that allows testing of IA drug delivery as first-line treatment, which is difficult to do in actual patients. METHODS: Wistar rats underwent left femoral artery catherization with a Balt Magic 1.2F catheter or Marathon Flow directed 1.5F Microcatheter with an Asahi Chikai 0.008 micro-guidewire which was navigated to the left internal carotid artery under x-ray. 25% mannitol was administered to test blood brain barrier breakdown (BBBB). Additional rats were implanted with C6 glioma cells in the left frontal lobe. C6 Glioma-Implanted Rats were monitored for overall survival and tumor growth. Tumor volumes from MRI images were calculated utilizing 3D slicer. Additional rats underwent femoral artery catheterization with Bevacizumab, carboplatin, or irinotecan injected into the left internal carotid artery to test feasibility and safety. RESULTS: A successful endovascular access and BBBB protocol was established. BBBB was confirmed with positive Evans-blue staining. 10 rats were successfully implanted with C6 gliomas with confirmed growths on MRI. Overall survival was 19.75 ± 2.21 days. 5 rats were utilized for development of our femoral catheterization protocol and BBBB testing. With regards to IA chemotherapy dosage testing, control rats tolerated targeted 10 mg/kg of bevascizumab, 2.4 mg/kg of carboplatin, and 15 mg/kg of irinotecan IA ICA injections without complications. CONCLUSIONS: We present the first endovascular IA rat glioma model that allows selective catheterization of the intracranial vasculature and assessment of IA therapies for gliomas without need for access and sacrifice of proximal cerebrovasculature.

Tiger Catheter for Difficult Femoral Artery Approach Coronary Catheterization

Background: While most catheters are designed for the natural anatomy of the coronaries at the origin, we often end up using multiple catheters in failed attempts to hook the coronary ostia in case of unusual origins. We had similar issues where we used multiple catheters in vain during femoral approach catheterizations and ended up successfully hooking with a tiger (TIG) catheter in a few of our cases in the catheterization laboratory. We mostly used Judkins left (JL) and Judkins right (JR) catheters as the first choice for femoral approach catheterizations. Hence, we wanted to see how frequently we had to use catheters other than JL and JR and which catheter was most useful in such cases. Methods: This is a retrospective study of catheterization laboratory angiographic data and recordings involving femoral artery approach coronary catheterization at King George Hospital, Visakhapatnam, from January 2022 to December 2022. We analyzed and interpreted the data of difficult femoral artery catheterizations where JL/JR catheters could not hook the coronaries successfully. We tabulated such data in percentages to understand which catheter was most useful in such cases. We analyzed the angiograms of such cases to understand the coronary origins. Results: Overall, 1130 cases underwent femoral artery approach coronary angiograms. Of them, 1100 (97.3%) cases could be hooked with JL and JR catheters. Thirty (2.65%) cases were found to be difficult femoral artery approach catheterizations where either JL or JR catheter could not be used successfully. Out of those difficult ones (30 cases – 100%), 22 (73.3%) cases could be hooked with TIG catheter, 4 (13.33%) cases with extra backup (EBU) catheter, 1 (3.33%) case with JR side hole (JRSH) catheter, 2 (6.66%) cases with no torque right (NTR) catheter, and 1 (3.33%) case with multipurpose catheter (MPA). Out of these 30 cases, a left coronary angiogram was needed other than a JL catheter in 8 cases, while a right coronary angiogram was needed other than a JR catheter in 25 cases, showing that the right coronary artery (RCA) was mostly involved in difficult catheterizations. For left coronary angiograms, 4 cases hooked with TIG (1 case – posteriorly/low takeoff, 1 – high takeoff, 1 – mid-takeoff, and 1 – RCA/left main coronary artery [LMCA] from left sinus) and 4 cases with EBU catheter (1 – anterior/high takeoff, 2 – high takeoffs, and 1 – posteriorly/high takeoff). For right coronary angiograms, 21 cases hooked with TIG (3 cases – left sinus/anteriorly, 3 – high takeoff/anteriorly, 3 – low takeoff, 2 – mid takeoff/anteriorly, 3 – posterior/high takeoff, 1 – RCA/LMCA from left sinus, 1 – posteriorly/left sinus, 3 – high takeoff, 1 – anteriorly/low takeoff, and 1 – right sinus/mid-takeoff), 1 case with JRSH, 1 case with MPA (anterior/high takeoff) and 2 cases with NTR (1 – low takeoff and 1 – high takeoff). Conclusion: We found that the TIG catheter was useful in difficult femoral approach catheterizations in the majority of cases and it can be tried in difficult cases.

Application of arterial infusion ports in hepatic arterial infusion chemotherapy and embolization for advanced hepatocellular carcinoma.

To investigate the safety and feasibility of subcutaneous implantable infusion ports in repeated hepatic arterial infusion chemotherapy (HAIC) for advanced hepatocellular carcinoma (HCC) in China. A total of 237 patients who were clinically diagnosed with advanced HCC (CNLC III a/III b) in our hospitals from December 2020 to October 2022 were retrospectively analyzed. The approaches of HAIC were divided into 2 groups: arterial infusion port implantation (group A) and one-time femoral artery catheterization (group B) based on the physicians' suggestion and the patients' intention. The comfort level (evaluated with the General Comfort Questionnaire), complications and average inpatient expenditure were compared between the 2 groups. 116 patients were finally enrolled in the study (group A: 69; group B: 47) and completed HAIC (FOLFOX-4 regimen) according to the dosing schedules (mean: 6±1 cycles). The comfort level of group A was greater than that of group B (p<0.05). The average inpatient expenditure of group A was lower than that of group B (5.4±2.4 vs 10.4±1.9 thousand yuan RMB/cycle, p<0.05). No patients developed port incision infection, hematoma or catheter-related thrombosis in group A, whereas four patients had groin hematomas, one had femoral artery dissection and four had deep vein thrombosis in group B. Hepatic arterial infusion chemotherapy via arterial infusion ports for advanced HCC decreased complications and medical expenditures and improved patient comfort levels compared with indwelling catheters.

Comparison of invasive and non-invasive measurements of cardiac index and systemic vascular resistance in living-donor liver transplantation: a prospective, observational study

BackgroundBased on the controversy surrounding pulmonary artery catheterization (PAC) in surgical patients, we investigated the interchangeability of cardiac index (CI) and systemic vascular resistance (SVR) measurements between ClearSight™ and PAC during living-donor liver transplantation (LDLT).MethodsThis prospective study included consecutively selected LDLT patients. ClearSight™-based CI and SVR measurements were compared with those from PAC at seven LDLT-stage time points. ClearSight™-based systolic (SAP), mean (MAP), and diastolic (DAP) arterial pressures were also compared with those from femoral arterial catheterization (FAC). For the comparison and analysis of ClearSight™ and the reference method, Bland-Altman analysis was used to analyze accuracy while polar and four-quadrant plots were used to analyze the trending ability.ResultsFrom 27 patients, 189 pairs of ClearSight™ and reference values were analyzed. The CI and SVR performance errors (PEs) exhibited poor accuracy between the two methods (51.52 and 51.73%, respectively) in the Bland-Altman analysis. CI and SVR also exhibited unacceptable trending abilities in both the polar and four-quadrant plot analyses. SAP, MAP, and DAP PEs between the two methods displayed favorable accuracy (24.28, 21.18, and 26.26%, respectively). SAP and MAP exhibited acceptable trending ability in the four-quadrant plot between the two methods, but not in the polar plot analyses.ConclusionsDuring LDLT, CI and SVR demonstrated poor interchangeability, while SAP and MAP exhibited acceptable interchangeability between ClearSight™ and FAC.

Comparison of ultrasound guidance and palpation technique for femoral artery catheterization in children undergoing cardiac surgery.

The aim of this study was compare the palpation technique and ultrasound-guidance for femoral artery catheterization in pediatric patients undergoing surgery for congenital heart disease. This prospective and randomized controlled study included American Society of Anesthesiologists III-IV 40 children who underwent congenital heart surgery. The patients were divided into two groups; ultrasound-guided catheterization group and palpation-guided catheterization group. Demographic and clinical characteristics of the patients, access time, success rate, number of attempts, first-attempt success, number of trials, and failed cannulations were recorded. The diameter of the femoral artery was significantly shorter, access time and numbers of trials were significantly lower, and first-attempt success rate was significantly higher in the US group. The complication rate was significantly higher in the P group. The number of failed catheterization was higher in the P group. Total cost required for the procedure was significantly lower in the US group. We found that ultrasound-guided arterial catheterization increases the success rate and the number of successful catheterizations, while reducing the overall procedure time, incidence of complications, and cost. Therefore, we believe that the use of ultrasound guidance in arterial catheterization in pediatric cardiac surgery would be a better choice.

Inhibition of integrin alpha v/beta 5 mitigates the protective effect induced by irisin in hemorrhage

IntroductionIrisin plays an important role in regulating tissue stress, cardiac function, and inflammation. Integrin αvβ5 was recently identified as a receptor for irisin to elicit its physiologic function. It remains unknown whether integrin αvβ5 is required for irisin's function in modulating the physiologic response to hemorrhage. The objective of this study is to examine if integrin αvβ5 contributes to the effects of irisin during the hemorrhagic response. MethodsHemorrhage was induced in mice by achieving a mean arterial blood pressure of 35–45 mmHg for one hour, followed by two hours of resuscitation. Irisin (0.5 μg/kg) was administrated to assess its pharmacologic effects in hemorrhage. Cilengitide, a cyclic Arg-Gly-Asp peptide (cRGDyK) which is an inhibitor of integrin αvβ5, or control RGDS (1 mg/kg) was administered with irisin. In another cohort of mice, the irisin-induced protective effect was examined after knocking down integrin β5 with nanoparticle delivery of integrin β5 sgRNA using CRSIPR/Cas-9 gene editing. Cardiac function and hemodynamics were measured using echocardiography and femoral artery catheterization, respectively. Systemic cytokine releases were measured using Enzyme-linked immunosorbent assay (ELISA). Histological analyses were used to determine tissue damage in myocardium, skeletal muscles, and lung tissues. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was carried out to assess apoptosis in tissues. ResultsHemorrhage induced reduction of integrin αvβ5 in skeletal muscles and repressed recovery of cardiac performance and hemodynamics. Irisin treatment led to significantly improved cardiac function, which was abrogated by treatment with Cilengitide or knockdown of integrin β5. Furthermore, irisin resulted in a marked suppression of tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1), muscle edema, and inflammatory cells infiltration in myocardium and skeletal muscles, which was attenuated by Cilengitide or knockdown of integrin β5. Irisin-induced reduction of apoptosis in the myocardium, skeletal muscles, and lung, which were attenuated by either the inhibition of integrin αvβ5, or knockdown of integrin β5. ConclusionIntegrin αvβ5 plays an important role for irisin in modulating the protective effect during hemorrhage.

The exercise pressor reflex - a pressure-raising mechanism with a limited role in regulating leg perfusion during locomotion in young healthy men.

We investigated the role of the exercise pressor reflex (EPR) in regulating the haemodynamic response to locomotor exercise. Eight healthy participants (23±3years, : 49±6ml/kg/min) performed constant-load cycling exercise (∼36/43/52/98% ; 4min each) without (CTRL) and with (FENT) lumbar intrathecal fentanyl attenuating group III/IV locomotor muscle afferent feedback and, thus, the EPR. To avoid different respiratory muscle metaboreflex and arterial chemoreflex activation during FENT, subjects mimicked the ventilatory response recorded during CTRL. Arterial and leg perfusion pressure (femoral arterial and venous catheters), femoral blood flow (Doppler-ultrasound), microvascular quadriceps blood flow index (indocyanine green), cardiac output (inert gas breathing), and systemic and leg vascular conductance were quantified during exercise. There were no cardiovascular and ventilatory differences between conditions at rest. Pulmonary ventilation, arterial blood gases and oxyhaemoglobin saturation were not different during exercise. Furthermore, cardiac output (-2% to -12%), arterial pressure (-7% to -15%) and leg perfusion pressure (-8% to -22%) were lower, and systemic (up to 16%) and leg (up to 27%) vascular conductance were higher during FENT compared to CTRL. Leg blood flow, microvascular quadriceps blood flow index, and leg O2 -transport and utilization were not different between conditions (P>0.5). These findings reflect a critical role of the EPR in the autonomic control of the heart, vasculature and, ultimately, arterial pressure during locomotor exercise. However, the lack of a net effect of the EPR on leg blood flow challenges the idea of this cardiovascular reflex as a key determinant of leg O2 -transport during locomotor exercise in healthy, young individuals. KEY POINTS: The role of the exercise pressor reflex (EPR) in regulating leg O2 -transport during human locomotion remains uncertain. We investigated the influence of the EPR on the cardiovascular response to cycling exercise. Lumbar intrathecal fentanyl was used to block group III/IV leg muscle afferents and debilitate the EPR at intensities ranging from 30% to 100% . To avoid different respiratory muscle metaboreflex and arterial chemoreflex activation during exercise with blocked leg muscle afferents, subjects mimicked the ventilatory response recorded during control exercise. Afferent blockade increased leg and systemic vascular conductance, but reduced cardiac output and arterial-pressure, with no net effect on leg blood flow. The EPR influenced the cardiovascular response to cycling exercise by contributing to the autonomic control of the heart and vasculature, but did not affect leg blood flow. These findings challenge the idea of the EPR as a key determinant of leg O2 -transport during locomotor exercise in healthy, young individuals.

Phenylephrine and norepinephrine increase blood pressure through opposing physiologic mechanisms in isoflurane-anesthetized dogs receiving acepromazine.

To elucidate the cardiovascular effects of escalating doses of phenylephrine and norepinephrine in dogs receiving acepromazine and isoflurane. 8 beagles aged 1 to 2 years (7.4 to 11.2 kg). All dogs received acepromazine 0.01 mg/kg, propofol 4 to 5 mg/kg, and isoflurane and were mechanically ventilated. Mean arterial pressure (MAP) from a femoral artery catheter and continuous electrocardiogram were recorded. Cardiac output (CO) was measured with transpulmonary thermodilution. Systemic vascular resistance (SVR), global end-diastolic volume (GEDV), and global ejection fraction (GEF) were subsequently calculated. Phenylephrine and norepinephrine were infused in random order at 0.07, 0.3, 0.7, and 1.0 μg/kg/min. All variables were measured after 15 minutes of each infusion rate. The effects of dose, agent, and their interaction on the change of each variable were evaluated with mixed-effect models. A P < .05 was used for significance. Atrial premature complexes occurred in 3 dogs during norepinephrine infusion at doses of 0.3, 0.7, and 1 μg/kg/min; no dysrhythmias were seen with phenylephrine administration. MAP increased during dose escalation (P < .0001) within each agent and did not differ between agents (P = .6). The decrease in HR was greater for phenylephrine (P < .0001). Phenylephrine decreased CO and GEF and increased GEDV and SVR (all P < .03). Norepinephrine decreased the SVR and increased CO, GEDV, and GEF (all P < .03). Our results confirm that phenylephrine increases arterial pressures mainly through vasoconstriction in acepromazine-premedicated dogs while norepinephrine, historically considered a vasopressor, does so primarily through an increase in inotropism.

Abstract P214: Impact Of NADPH Oxidase 4 Knockout On Renal O 2 Consumption In Dahl Salt-sensitive Rats

It has been generally thought that in normal Sprague-Dawley (SD) rats, a high salt diet has minimal impact on blood pressure and kidney function. However, as we have recently reported, the kidneys of SD rats fed a 4.0% NaCl diet (HS) exhibit enhanced O 2 consumption (VO 2 ) and marked changes in the metabolic pathways responsible for the generation of ATP and reactive oxygen species (ROS). In the current study, we examined the level of renal VO 2 in Dahl salt-sensitive (SS) rats and those in which the NADPH Oxidase 4 (NOX4) gene was globally knocked out (SS Nox4 -/- ). Male SS (n=9) and SS Nox4 -/- (n=10) rats were fed a 0.4% NaCl (LS) diet. At 7-8 weeks of age, the rats were implanted with a renal artery ultrasonic flow probe (Transonic) together with a femoral arterial catheter and a renal venous catheter. Renal blood flow (RBF) and mean arterial pressure (MAP) were measured continuously (24/7) and arterial (A) and renal venous (Vr) blood was sampled intermittently when rats were fed a LS and on days 7, 14, and 21 after switching to a HS diet. Blood O 2 content was immediately measured by a radiometer. The average 24-hour MAP of SS rats rose after switching to a HS diet from 122 ± 2 on the LS to 140 ± 2 on HS7, and to 164 ± 5 by HS21. In contrast, MAP in SS Nox4 -/- rats increased from 121 ± 2 mmHg at LS to 132 ± 1 mmHg at HS7 and 152 ± 3 mmHg at HS21 (p&lt;0.05). RBF was not significantly changed but tended to progressively rise in both strains of rats with 24-hr flows averaging 7.8 ± 0.7 ml/min when fed LS and 8.9 ± 1.0 ml/min at HS21, and SS Nox4 -/- from 6.9 ± 0.7 to 8.2 ± 0.9. Normalized by changes of kidney weights obtained in another group of SS and SS Nox4 -/- rats, RBF was significantly reduced over the 3 weeks of the HS diet given the increase of kidney weights (SS LS 7.0 ± 0.6, HS7 5.7 ± 0.5, HS21 4.9 ± 0.6; SS Nox4 -/- LS 6.4 ± 0.7, HS7 6.2 ± 0.7, HS21 5.4 ± 0.7). Most importantly, the O 2 extraction ratio at LS was lower in SS Nox4 -/- (10.5 ± 1.0%) compared to SS (14.6 ± 1.0%) (p&lt;0.05). When switched to the HS diet, this was further reduced in the SS Nox4 -/- rats reaching 7.6 ± 0.9% at HS21 (p&lt;0.05), while it did not change significantly in SS (13.3 ± 1.4%) at HS21. We conclude that the elevated levels of renal O 2 consumption observed in SS rats are at least in part a consequence of increased oxidative stress associated with NOX4.

MicroRNA profiling in dogs undergoing induced ischemic heart infarction: An experimental study.

MicroRNAs (miRNAs) play an important role in various biological functions. According to many studies, miRNA expression is tissue-specific, strongly controlled throughout embryogenesis, and over- or under-expressed in numerous disorders, including cardiovascular pathologies. This study aimed to screen, characterize, and profile many induced biomarkers (miRNAs) in dog serum before and after experimentally inducing a regional myocardial infarction (MI) by occluding the coronary arteries under general anesthesia. A preclinical experimental animal study recruited 12 healthy canine dogs. The selected canine dogs were anesthetized with 1 mg/kg xylazine and 15 mg/kg ketamine before undergoing femoral arterial catheterization under fluoroscopic supervision. Commercial assay kits were used to purify total RNA and miRNA before the occlusion and 2 h after the occlusion according to the manufacturer's guidelines, and the samples were stored in RNase/DNase-free water at -80°C. Data were analyzed by GraphPad Prism 5.0 software (GraphPad Prism, San Diego, CA) SPSS, and GenEx software (www.multid.se) or (REST V3). Among 325 transcribed genes, 20 were identified in 2 h. After MI, 14 biomarkers were negative, indicating downregulation, and 6 (3-F08, 3-B10, 4-A11, 1-A06, 2-E01, 3-F10) were positive, indicating upregulation. Polymerase chain reaction assay results showed a normalized fold-change in gene expression in the test sample. Fold values >1 represented a biologically significant change. Profiling of miRNAs before and after MI in a dog model revealed upregulation of six previously unidentified biomarkers (3-F08, 3-B10, 4-A11, 1-A06, 2-E01, and 3-F10), indicating various miRNA regulatory patterns.

Differential benefits of physical training associated or not with l-arginine supplementation in rats with metabolic syndrome: Evaluation of cardiovascular, autonomic and metabolic parameters

Metabolic syndrome (MetS) is characterized by endocrine-metabolic and cardiac alterations that increase the risk of cardiovascular disease, dyslipidemia, and type-2 diabetes mellitus. Dietary supplementation with l-Arginine (L-Arg) is beneficial for fat loss, while chronic aerobic exercise has several benefits in reversing cardiovascular, autonomic, and metabolic dysfunctions caused by obesity. However, the association between these two approaches has not yet been described. This study aimed to evaluate the possible benefits of physical training, with or without l-Arg-supplementation, on cardiovascular, autonomic, and metabolic parameters in rats with MetS, which was induced by the subcutaneous administration of monosodium glutamate at 4 mg g−1day−1 in rats from the first to fifth day of life. Physical training on a treadmill and supplementation with l-Arg-in adulthood were carried out concomitantly for 8 weeks. After this, the animals underwent femoral artery catheterization to record their cardiovascular parameters and autonomic modulation. Organs and blood were removed to measure levels of nitrite, glucose, and hepatic steatosis. In adult rats with MetS, supplementation with l-Arg-in combination with physical training reduced hypertension, tachycardia, adipose tissue mass, free fatty acids, and hepatic steatosis. Supplementation with l-Arg-and physical training separately was beneficial in reducing several aspects of MetS, but a combination of both was especially effective in reducing adipose tissue and hepatic steatosis. Together, the two therapies can form a good strategy to combat MetS.

Frequency and Predictors of Acute and Persistent Femoral Artery Occlusion in Infants with Congenital Heart Disease: A Study Using Ultrasonography for Arterial Access and the Diagnosis of Arterial Occlusion.

Femoral arterial access is challenging in infants. Furthermore, after cardiac catheterization, femoral arterial occlusion (FAO) can be underestimated and easily missed on physical examination. Ultrasound is recommended for femoral arterial access and the correct diagnosis of FAO; however, few studies have reported its effectiveness.To investigate the frequency and risk factors of acute loss of the arterial pulse (ALAP) and persistent femoral arterial occlusion (PFAO) in infants with congenital heart disease who underwent ultrasound-guided femoral arterial access (US-GFAA) and were diagnosed with FAO by ultrasound.We obtained data related to patient characteristics, access variables of US-GFAA, and ultrasonography findings of the femoral artery from our pediatric cardiac catheterization database between August 2017 and August 2022. We divided the patients into groups based on the presence of ALAP and PFAO. We identified ALAP in 99 (19%) patients and PFAO in 21(4%) of 522 patients in the study. The median patient age was 132days (interquartile range: 75-202days). The logistic regression analysis identified younger age, aortic coarctation, previous catheterization of the same femoral artery, larger sheath size (5F), and longer duration of cannulation as independent risk factors for ALAP and younger age as an independent risk factor for PFAO (all p < 0.05). This study showed that younger age at procedure was a risk factor for both ALAP and PFAO, while aortic coarctation, previous arterial catheterization, use of a larger sheath and longer duration of cannulation were risk factors for ALAP in infants. The majority of FAO is reversible and secondary to arterial spasm, and the of FAO increases inversely with patient age.