Artery Clamping Research Articles

Ultrasound-guided renal artery balloon catheter occluded hybrid partial nephrectomy (UBo-HPN) with branch renal artery occlusion: a single arm trial

BackgroundOne key focus of partial nephrectomy is preserving renal function. Segmental renal artery occlusion with microdissection at the renal hilum confines ischemia, effectively reducing warm ischemic injury. Ultrasound-Guided Renal Artery Balloon Catheter Occluded Hybrid Partial Nephrectomy (UBo-HPN) can achieve branch occlusion without the need for dissecting the renal hilum.ObjectiveTo investigate the feasibility and safety of UBo-HPN of branch renal artery occlusion in the treatment of localized renal tumors.Subject and methodsA prospective single-arm analysis involving 20 patients with renal localized tumors underwent robot assisted UBo-HPN with branch renal artery occlusion from August 2021 to July 2023, with an average follow-up of 12 months.ResultsAll patient was successfully operated on without conversion to conventional arterial clamping or radical nephrectomy. One case (5%) of minor complication occurred in the whole cohort, which was bruising around the puncture site. The mean total operative time was 95.8 min, with a mean operative time of 21.25 min for vascular intervention. The mean warm ischemia time was 20.35 min, and the median estimated blood loss was 50 ml. The median eGFR preservation percentage at postoperative 48 h, 30 days, and the latest follow-up were 87.52%, 91.47%, and 92.2%, respectively. After a median follow-up of 10.2 (2.3–19.2) months, no patients had radiological tumor recurrence or died from tumor-related causes.ConclusionsUBo-HPN with renal artery branch occlusion emerges as an efficient alternative to partial nephrectomy (PN), which achieved branch artery occlusion without dissecting the renal hilum. Long-term follow-up is expected for functional outcomes.

Renal Artery Blood Flow and Surface Parenchymal Perfusion During Renal Artery Endoshunting in a Porcine Model

ObjectiveIschaemia and reperfusion can result in permanent tissue damage. During complex open abdominal aortic surgery, transient clamping of renovisceral arteries may be required to successfully complete the vascular repair. Endovascular shunting (endoshunting) presents an alternative technique for managing such temporary renovisceral ischaemia. This study aimed to investigate the performance of endoshunting to the renal circulation in a porcine model. MethodsThis study of five domestic pigs investigated arterial volume flow rates during endoshunting of a single renal artery and the associated impact on renal perfusion parameters (laser Doppler renal parenchymal perfusion, renal oxygen extraction, and selective urinary output). The study was performed in three steps: baseline registrations (30 minutes), endoshunting (120 minutes), and restitution (60 minutes). The right kidney was used as the experimental side and the left kidney as control. ResultsThe median arterial flow rate in the left control kidney remained constant throughout the experiment. On the right (endoshunted) side, the baseline median arterial flow rate was 267 (range, 160 – 404) mL/min. Following activation of the endoshunt, the median arterial volume flow dropped by 59% to 110 (range, 45 – 150) mL/min (p = .018). During endoshunting, the median kidney surface perfusion decreased to 42% of the baseline value. On the control side, a rise in the median parenchymal perfusion was observed after endoshunt activation, which was again normalised following restitution of native right renal artery flow. During endoshunting, the median regional urine production was 0.32 (range, 0.12 – 0.50) mL/hour but resumed after renal artery flow restitution. ConclusionOn average, the endoshunted kidneys showed a rapid restoration of blood flow, parenchymal perfusion, and urine production after 120 minutes of endoshunting. This suggests that endoshunting to the kidney using an endoshunt system might be a promising strategy to preserve renal function when a temporary interruption of native renal artery blood flow is needed during complex vascular surgical repairs involving the renal arteries.

Germacrone ameliorates acute lung injury induced by intestinal ischemia-reperfusion by regulating macrophage M1 polarization and mitochondrial defects.

Intestinal ischemia-reperfusion (I/R) injury severely affects the lungs. Germacrone (Ger) possesses anti-inflammatory and antioxidant properties. However, it is unclear whether it protects the lungs from I/R injury. In this study, we elucidate the mechanisms by which Ger protects lungs from I/R injury. C57BLKS/J male mice are subjected to I/R injury via complete clamping of the superior mesenteric artery. Ger is administered before intestinal I/R. Mitochondrial morphology is observed via electron microscopy. The histopathology of the lung tissues is monitored via hematoxylin-eosin and immunofluorescence staining. The mitochondrial oxygen consumption rate is measured via an XF96 extracellular flux analyzer. In the I/R mouse model, lung specimens present significant lung damage accompanied by increases in the levels of collagen III, vimentin, and α-SMA in lung tissues. After treatment with Ger, lung impairment and fibrosis in I/R-induced acute lung injury (ALI) model mice are restored, suggesting that Ger improves I/R-ALI. In addition, Ger administration decreases the release of inflammatory factors such as IL-1β, IL-6, and COX2, as well as the expressions of M1 macrophage markers, facilitating cell survival in the I/R-ALI model. Additionally, Ger (EC50: 47.16 μM) ameliorates mitochondrial dysfunction by increasing I/R-ALI-induced apoptosis, increasing the expression of SIRT1, and reducing the levels of HIF1-α, Nrf2, and OGG1 in MLE-12 cells. Ger may affect macrophage polarization and improve subsequent mitochondrial defects through the SIRT1-HIF1α-Nrf2 signaling pathway in MLE-12 cells, which ultimately improves lung function and lung inflammation in the I/R-ALI model.

Temporary clamping of the uterine arteries versus coventional technique for the prevention of postpartum hemorrage during cesarean section: a randomized controlled trial study

BackgroundCesarean sections are the most common abdominal surgical interventions worldwide, with increasing rates in both developed and developing countries. Postpartum (hemorrhage PPH) during cesarean sections can lead to maternal morbidity, prolonged hospital stays, and increased mortality rates. Although various non-surgical measures have been recommended for PPH prevention, surgical techniques such as uterine artery ligation and embolization have been used to manage PPH effectively.ObjectiveThis study aimed to evaluate the effectiveness of a surgical technique based on the temporary bilateral clamping of uterine arteries to reduce blood loss during cesarean sections.MethodsA longitudinal prospective, randomized, controlled study was conducted with a preliminary population group of 180 patients at the University Hospital Regional de Málaga from November 2023 to January 2024. The study protocol was approved by the Ethics Committee of the Regional University Hospital of Malaga (protocol 1729-N-23 and registred with ISRCTN15307819|| http://www.isrctn.org/, Date submitted 12 June 2023 ISRCTN 15307819). The patients were divided into two groups based on whether the clamping technique was applied during their cesarean sections. The study assessed hemoglobin levels before and after surgery, hospitalization durations, and the prevalence of anemia at discharge as the primary outcomes.ResultsThe patients who underwent the clamping technique demonstrated significant reductions in hemoglobin differences (0.80 g/dL) compared to the control group (1.42 g/dL). The technique also resulted in shorter hospital stays (3.02 days vs. 3.90 days) and a lower prevalence of anemia at discharge (76.2% vs. 60%).ConclusionTemporary clamping of uterine arteries during cesarean sections appears to be an effective measure for preventing postpartum hemorrhaging, reducing hospital stays, and decreasing the prevalence of anemia at discharge. Further research with larger sample sizes and standardized indications is warranted to confirm the benefits and potential broader applications of this technique.Trial registrationISRCTN 15,307,819.

Comparison of renal function between the artery and vein clamp and artery-only clamp in robot-assisted partial nephrectomy for moderate- to high-complexity renal masses: A propensity-matched study.

Artery and vein (AV) clamps can control venous bleeding in the surgical field and prevent carbon dioxide embolism, especially when large veins are expected to open. However, whether AV clamps cause more renal damage than artery-only (AO) clamps remains unclear. This study aimed to compare renal function and blood loss in surgeries using AO and AV clamps based on high RENAL nephrometry scores (RNS) in robot-assisted partial nephrectomy (RAPN). We retrospectively analyzed the medical records of 500 patients who underwent RAPN between March 2016 and December 2021. We performed 1:1 propensity matching for these patients. A total of 340 patients with pathological malignancies who were followed up for at least 12 months were included in this analysis. A total of 291 patients with AO clamping and 49 patients with AV clamping were included. Overall, the AV clamp group had higher total RNSs and larger diameters than the AO clamp group. Propensity score-matched analysis included 37 patients in each clamp group. The median warm ischemia times of the AV and AO clamps were 25 and 22 min, respectively, with no significant difference. There were no statistically significant differences between the groups in the amount of blood loss, rate of acute kidney injury (AKI), or renal function at 1, 3, or 12 months post-RAPN. Compared with the AO clamp, the AV clamp did not have a detrimental impact on blood loss or renal dysfunction. Consequently, AV clamps may be considered for patients presenting with moderate-to-high-complexity RNSs.

Altered kidney distribution and loss of ACE2 into the urine in acute kidney injury.

There are diverse pathophysiological mechanisms involved in acute kidney injury (AKI). Among them, overactivity of the renin-angiotensin system (RAS) has been described. Angiotensin-converting enzyme 2 (ACE2) is a tissue RAS enzyme expressed in the apical border of proximal tubules. Given the important role of ACE2 in the metabolism of angiotensin II, this study aimed to characterize kidney and urinary ACE2 in a mouse model of AKI. Ischemia-reperfusion injury (IRI) was induced in C57BL/6 mice by clamping of the left renal artery followed by removal of the right kidney. In kidneys harvested 48 h after IRI, immunostaining revealed a striking maldistribution of ACE2 including spillage into the tubular lumen and the presence of ACE2-positive luminal casts in the medulla. In cortical membranes, ACE2 protein and enzymatic activity were both markedly reduced (37 ± 4 vs. 100 ± 6 ACE2/β-actin, P = 0.0004, and 96 ± 14 vs. 152 ± 6 RFU/μg protein/h, P = 0.006). In urine, full-length membrane-bound ACE2 protein (100 kDa) was markedly increased (1,120 ± 405 vs. 100 ± 46 ACE2/µg creatinine, P = 0.04), and casts stained for ACE2 were recovered in the urine sediment. In conclusion, in AKI caused by IRI, there is a marked loss of ACE2 from the apical tubular border with deposition of ACE2-positive material in the medulla and increased urinary excretion of full-length membrane-bound ACE2 protein. The deficiency of tubular ACE2 in AKI suggests that provision of this enzyme could have therapeutic applications and that its excretion in the urine may also serve as a diagnostic marker of severe proximal tubular injury.NEW & NOTEWORTHY This study provides novel insights into the distribution of kidney ACE2 in a model of AKI by IRI showing a striking detachment of apical ACE2 from proximal tubules and its loss in urine and urine sediment. The observed deficiency of kidney ACE2 protein and enzymatic activity in severe AKI suggests that administration of forms of this enzyme may mitigate AKI and that urinary ACE2 may serve as a potential biomarker for tubular injury.

Abstract P356: Sex-dependent Response of ATP-mediated Calcium in Renal Microvascular Smooth Muscle Cells in Ischemia-reperfusion Rats

Renal autoregulation is intrinsic to preglomerular microvascular smooth muscle cells (MVSMC) for maintaining stable renal blood flow and glomerular filtration rate during arterial pressure fluctuations. Our recent study suggests that renal ischemia-reperfusion (IR) leads to sex-dependent autoregulatory impairment of afferent arterioles. Renal autoregulation is linked to ATP sensitive-Ca 2+ signaling in MVSMC via activation of P2X purinoceptors (P2X). ATP vasoconstricts afferent arterioles by increasing intracellular calcium concentration ([Ca 2+ ] i ) in male rat MVSMC but female rats have not been studied. We postulate that female MVSMC exhibit highly sensitive ATP-mediated Ca 2+ responses which may protect females against IR. Blood-perfused juxtamedullary nephron experiments were performed on kidneys of Sprague-Dawley rats 24 hours after IR (60-min, bilateral renal artery clamping). ATP-induced changes in [Ca 2+ ] i were assessed in freshly isolated MVSMC using Fura-2. Superfusion of ATP (10 -8 –10 -4 M) elicited concentration-dependent vasoconstriction in sham rats of both sexes. The maximal vasoconstriction was 68±2% of the control diameters at 10 -4 mol/L in males and 72±9% in females (n=3/group). In contrast, ATP-induced vasoconstriction was nearly abolished in both sexes 24 h post-IR. The maximal vasoconstriction only reached 91±6% and 97±3% of control diameter in male and female IR rats (n=3/group, P <0.05 vs. shams), respectively, indicating impaired P2X signaling in afferent arterioles post-IR. ATP exposure increased [Ca 2+ ] i in control MVSMC of both sexes by 0.03±0.00 and 0.10±0.01 in males and 0.19±0.02 and 0.43±0.05 in females at 10 -5 and 10 -4 M ATP, respectively. The ATP-induced increase in [Ca 2+ ] i was 4-7 fold higher in female than in male controls, suggesting that MVSMC from normal female rats exhibit a highly sensitive response to ATP stimulation versus male’s. IR suppressed ATP-induced calcium responses in MVSMC of both sexes. [Ca 2+ ] i increased by 0.02±0.00 and 0.04±0.01 in IR males and 0.09±0.01 and 0.09±0.01 in IR females in response to 10 -5 and 10 -4 M ATP, respectively (P <0.05 vs control, n=60-150 cells/3-4 rats/group). Female IR MVSMC however, still possess higher reactivity to ATP than MVSMC from male shams. In conclusion, our studies suggest that MVSMC of male and female rats handle ATP-Ca 2+ signaling differently and the stronger ATP-mediated [Ca 2+ ] i response in female MVSMC may protect females against IR-induced kidney injury.

Ischemia time in partial nephrectomy: to rush really matters?

Aim: The growth in the incidence of small renal masses has led the implementation of laparoscopic partial nephrectomy to become the technique of choice. However, arterial clamping and secondary renal ischemia still mean a controversial issue due to the risk of renal failure. Our objective is to evaluate the existing literature and its relationship to our experience. Methods: We performed a retrospective study of our series over six years. We analyzed different clinical, perioperative and postoperative functional outcome variables and compared the relationship between tumor complexity and the need for ischemia as well as the relation between ischemia time and renal function over a follow-up time of 6 months. For the discussion, we led a review of the literature on the subject and the paradigm shift that has taken place over the years. Results: A total of 148 patients, most of them male (68.2%) with an average age of 62.4 [standard deviation (SD) 1.7] years, had a Charlson index of 3 [interquartile range (IQR) 1-4]. The average R.E.N.A.L. score was 6 (IQR 5-8). Intraoperative complications were observed in 8.1% of the cases, most of which involved bleeding from a major artery or vein (7.4%). Postoperative complications occurred in 23.6% of the patients, the majority being classified as Clavien 2. Arterial clamping was carried out in 52.7% of the interventions, with a median ischemia time of 8 min (IQR 0-18). The average hospital stay was three days (IQR 2-5). Previous median glomerular filtration rate (GFR) was 83 mL/min/1.73 m2 (IQR 66.2-93.6). On the first postoperative day, the median GFR was 78.4 (SD 21.8), and at 6 months, it was 75.2 (SD 22). We found no statistically significant differences between having hypertension or diabetes mellitus and GFR after surgery, but we found differences in the correlation of a Charlson index ≥ 3 and deterioration of renal function, being the P values 0.01, 0.08 and 0.00 for the first postoperative day, after three and 6 months, respectively. No statistically significant differences were found in whether having a previous chronic kidney disease influenced the decision to perform arterial clamping or not, with a P value of 0.104. Statistically significant differences were found in the relationship between R.E.N.A.L. score and ischemia time. Conclusion: Renal tumors with a higher R.E.N.A.L. score involve the need to accomplish a longer arterial clamping, but its relationship with the deterioration of renal function is unclear, since there are other risk factors, such as patient’s comorbidities.

Hydrogen sulphide reduces renal ischemia-reperfusion injury by enhancing autophagy and reducing oxidative stress.

Renal ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury. Hydrogen sulphide (H2S) exerts a protective effect in renal IRI. The present study was carried out to investigate the effects of exogenous H2S on renal IRI by regulating autophagy in mice. Mice were randomly assigned to control, IRI and NaHS (an H2S donor, 28, 56 and 100 μmol/kg) groups. Renal IRI was induced by clamping the bilateral renal pedicles with non-traumatic arterial clamp for 45 min and then reperfused for 24 h. Mice were administered intraperitoneally with NaHS 20 min prior to renal ischemia. Sham group mice underwent the same procedures without clamping. Serum and kidney tissues were harvested 24 h after reperfusion for functional, histological, oxidative stress, and autophagic determination. Compared with the control group, the concentrations of serum creatinine (Scr), blood urea nitrogen (BUN), and malondialdehyde (MDA), the protein levels of LC3II/I, Beclin-1 and P62, as well as the number of autophagosomes were significantly increased, but the activity of superoxide dismutase (SOD) was decreased after renal IRI. NaHS pre-treatment dramatically attenuated renal IRI-induced renal dysfunction, histological changes, MDA concentration and p62 expression in a dose-dependent manner. However, NaHS increased the SOD activity and the protein levels of LC3II/I and Beclin-1. These results indicate that exogenous H2S protects the kidney from IRI through enhancement of autophagy and reduction of oxidative stress. Novel H2S donors could be developed in the treatment of renal IRI.

Economic analysis of the use of holmium enucleation of the prostate and laparoscopic simple prostatectomy in the surgical treatment of large-volume prostatic hyperplasia

Introduction. The method of choice for surgical treatment of benign prostatic hyperplasia (BPH) with a volume of more than 80 сс is holmium enucleation of the prostate (HoLEP). However, laser enucleation of the prostate is associated with limitations that carry both a clinical and financial burden. Laparoscopic simple prostatectomy (LSP) has now emerged as an alternative to transurethral procedures. In addition to ensuring clinical efficacy, optimal approaches to surgical management of large-volume BPH must also be financially viable, which underlines the significance of this study.Objective. To conduct a comparative economic analysis of holmium laser enucleation of the prostate and laparoscopic retropubic simple prostatectomy combined with temporary clamping of the internal iliac arteries and vesicourethral anastomosis (LSP + TCA + VUA).Materials & methods. An economic analysis of the results of HoLEP (214 people) and LSP + TCA + VUA (215 people) was conducted in a multicenter, open-label study. The economic analysis aimed to calculate the direct costs associated with surgery, as well as indirect costs related to hospitalization. A comparative analysis of drug prescriptions was conducted, including an assessment of costs for conservative treatment during hospitalization and the postoperative period. The economic losses associated with the duration of patients' temporary disability were calculated as the total loss in gross domestic product (GDP) production.Results. The cost of basic surgical equipment was 15,701,000.0 and 36,927,827.0 rubles (₽) for LSP + TCA + VUA and HoLEP, respectively. The median direct costs for performing LSP + TCA + VUA and laser enucleation HoLEP was 54,990.6 [49,870.5; 67,850.8] and 69,158.9 [65,005.9; 72,351.7] ₽, respectively. The median of indirect costs in the LSP + TCA + VUA and HoLEP groups was 71,251.0 [68,039.0; 73,103.0] and 80,451.0 [74,423.0; 83,501.0] ₽, respectively. The indicators of lost profits in GDP production per person were 5,398.4 and 6,167.9 ₽ in the LSP + TCA + VUA and HoLEP groups, respectively.Conclusion. The rationale for the use of LPA + VPA + UCA in the surgical treatment of large-volume BPH is based on economically justified advantages compared with HoLEP.

Pancreaticoduodenectomy in Patients With Coeliac or Superior Mesenteric Artery Stenosis: A Review of the Literature.

Pancreaticoduodenectomy (Whipple's procedure) is a technically demanding operation performed for malignant and premalignant conditions of the pancreatic head, duodenum and bile duct. Awareness of the vascular anatomy, variations, and pathology of this area is essential to achieve safe surgery and good outcomes. The operation involves division of the gastroduodenal artery (GDA) which provides communication between the foregut and midgut blood supply. In patients with coeliac or superior mesenteric artery (SMA) stenosis, this can lead to reduced blood supply to the foregut or midgut organs, with consequent severe ischaemic complications leading to significant morbidity and mortality. Coeliac artery stenosis is caused by median arcuate ligament syndrome (MALS) in the majority of patients with atherosclerosis being the second most common cause. SMA stenosis is much less common and is caused in the majority of cases by atherosclerosis. A review of preoperative imaging and intraoperative gastroduodenal artery clamp test is important to identify cases that may need additional procedures to preserve the blood supply. In this paper, we present a literature review for studies reporting patients undergoing Whipple's operation with concomitant coeliac axis stenosis (CAS) or SMA stenosis. Analysis of causes of stenosis or occlusion, prevalence, risk factors, different management strategies and outcomes was conducted.

Is temporary clamping of the bilateral common iliac artery beneficial in reducing intraoperative blood loss in patients with segmental resected anterior placenta percreta?: A prospective observational study.

The aim of our study was to investigate whether temporary clamping of the bilateral common iliac artery (BCIA) has a role in reducing intraoperative blood loss in patients with segmentally resected anterior placenta percreta or not. This prospective observational study included patients with anterior placenta percreta who underwent cesarean segmental resection either with BCIA temporary clamping or without clamping between October 2022 and September 2023. A comparison of demographic, obstetric, and surgical parameters and the need for transfusion (except for postoperative erythrocyte suspension transfusion) between the two groups revealed no significant difference (P > 0.05). In contrast, the amount of intraoperative blood loss (P = 0.001) (1974 ± 749 mL vs 2702 ± 615 mL) and postoperative erythrocyte suspension transfusion (P = 0.046) in patients who underwent BCIA temporary clamping were significantly lower than in those who did not undergo BCIA temporary clamping. Temporary clamping of BCIA plays a significant favorable role both in reducing blood loss and the need for postoperative transfusion in patients with placenta percreta who underwent segmental uterine resection.

A Unique Emotional Surgery: Removal of Unexploded Ordnance in a Patient With Vascular Injury.

Cases of embedded unexploded ordnance are extremely rare and pose a risk to bystanders and health providers. A patient arrived at the Role 2 medical facility in the Turkish army, whose left arm was amputated due to a terrorist attack and major hemorrhages had been halted by clamping of the left subclavian artery and vein. A piece of metal wire running from the lateral chest wall was detected as an unexploded ordnance piece and it was removed surgically. In these challenging cases, safety principles should be acknowledged. Highlighting the basic precautions is important for similar scenarios and increases awareness of the utmost importance.

Sevoflurane enhances autophagy via Rac1 to attenuate lung ischaemia‒reperfusion injury

Sevoflurane can attenuate lung ischaemia‒reperfusion injury (LIRI). However, the protective mechanism is unclear. In this study, we developed a LIRI model in vivo that animals (SD, n = 15) were subjected to the administration of 2.2 % sevoflurane 30 min before the onset of left pulmonary artery clamping for 45 min, which was then followed by 60 min of reperfusion treatment. Then, transcriptome sequencing was used to analyse lung tissues. Autophagy inhibition (3-MA) and Rac1-overexpression transfection plasmids were used in BEAS-2B cells, and BEAS-2B cells were subjected to hypoxia reoxygenation (H/R) and sevoflurane treatment. In both animal tissue and cells, inflammatory cytokines and apoptotic and autophagy molecules were measured by quantitative real-time PCR, western blotting and immunostaining. As a result, decreased arterial partial oxygen and damage to the histological structure of lung tissues were observed in LIRI model rats, and these effects were reversed by sevoflurane treatment. Activation of inflammation (elevated IL-1β, IL-6, and TNF-α) and apoptosis (elevated cleaved caspase3/caspase3 and Bax, degraded expression of Bcl2) and inhibition of autophagy (elevated P62, degraded expression of Beclin1 and LC3-II/LC3I) in the model group were ameliorated by sevoflurane. Transcriptome sequencing indicated that the PI3K/Akt pathway regulated by Rac1 plays an important role in LIRI. Furthermore, overexpression of Rac1 in a cell line inhibited the protective effect of sevoflurane in LIRI. Autophagy inhibition (3-MA) also prevented the protective effect of sevoflurane on inflammation and apoptosis.As shown in the present study, sevoflurane enhances autophagy via Rac1/PI3K/AKT signalling to attenuate lung ischaemia‒reperfusion injury.

Correlation of diabetic renal hypoperfusion with microvascular responses of the skeletal muscle: a rat model study using diffuse correlation spectroscopy.

Using diffuse correlation spectroscopy, we assessed the renal blood flow and thigh muscle microvascular responses in a rat model of type 2 diabetes. The blood flow index at the renal surface decreased significantly with arterial clamping, cardiac extirpation, and the progression of diabetic endothelial dysfunction. Renal blood flow measured in diabetic and nondiabetic rats also showed a significant correlation with the reactive hyperemic response of the thigh muscle. These results suggest shared microcirculatory dysfunction in the kidney and skeletal muscle and support endothelial responses in the skeletal muscle as a potential noninvasive biomarker of renal hypoperfusion.

#2339 All-trans retinoic acid enhances the efficacy of mesenchymal stem cells in acute kidney injury

Abstract Background and Aims Mesenchymal stem cells (MSCs) have emerged as a promising therapeutic strategy for acute kidney injury (AKI), but still suffer from the drawbacks of low survival rate, low homing rate, and uncertain differentiation. In search of better therapeutic strategies, we explored all-trans retinoic acid (ATRA) pretreatment of MSCs to observe whether it could improve the therapeutic efficacy on AKI. Method We established a renal ischemia/reperfusion (I/R) injury model induced by clamping of left renal artery for 30 minutes and contralateral nephrectomy. C57BL/6 mice were randomly divided into 4 groups: sham group, IRI group, MSCs group, and ATRA-MSCs group. MSCs or ATRA-pretreated MSCs were injected via tail vein. GFR was measured by transcutaneous monitoring the clearance of FITC-sinistrin. These mice were sacrificed 3 days after surgery, and the serum creatinine (SCr) and blood urea nitrogen (BUN) levels were measured. The renal pathological changes were examined by Periodic Acid-Schiff staining (PAS). The in vitro hypoxia/reoxygenation (H/R) model was established using human proximal tubular epithelial cells (HK-2 cells). Co-culturing HK-2 cells with MSCs or ATRA-pretreated MSCs. Western blot, quantitative real time-PCR (qRT-PCR), and immunohistochemistry were used to detect mRNA or protein expression. We performed RNA sequencing (RNA-seq) analysis in ATRA-pretreated MSCs. The content of hyaluronic acid (HA) in the supernatant of ATRA-pretreated MSCs culture was detected by ELISA. Hyaluronan synthase mRNA expression level in ATRA-pretreated MSCs assessed by qRT-PCR analysis. The HAS2 promoter-binding transcription factors were forecasted by the JASPAR Transcription Factor Binding Site database. Western blot was used to detect whether P13K/AKT pathway was activated by ATRA-pretreated MSCs. Whether this nephroprotective effect could be reversed were explored by silencing HAS2 or CD44 antibodies. Results The AKI mice showed a significant decrease in GFR and even complete loss of renal function. Administration of MSCs significantly increased GFR, and MSCs pretreated with ATRA further increased GFR. Mice injected with ATRA-pretreated MSCs had significantly lower levels of SCr, BUN and ATN scores compared with untreated MSCs. Western blot, quantitative real-time PCR (qRT-PCR), and immunohistochemistry showed that ATRA pretreated MSCs were more effective in reducing AKI inflammation and apoptosis and promoting proliferative repair than untreated MSCs. GO enrichment analysis demonstrated that the hyaluronan biosynthetic process may be a significantly expressed. HAS2 expression and HA content of MSCS were significantly increased after the addition of ATRA. Analysis for potential transcription factor binding sites revealed that the HAS2 promoter region has multiple potential binding sites for the retinoic acid receptor. Based on the predictions from the JASPAR database, the RXR-RAR heterodimer had the highest prediction score. We then performed ChIP analysis to experimentally verify the binding of RXR-RAR heterodimer transcription factor to HAS2 promoters. We further found that ATRA-pretreated MSCs activated the PI3K/AKT signaling pathway in AKI. As expected, we found that ATRA-pretreated MSCs anti-inflammatory, anti-apoptosis, and pro-proliferation effects were substantially reversed by silencing HAS2 or blocking CD44. Conclusion ATRA promotes HA secretion from MSCs and activates the PI3K/AKT pathway, which in turn enhances the therapeutic efficacy of MSCs on AKI.

A Bosniak III Cyst Unmasking Tubulocystic Renal Cell Carcinoma in an Adolescent: Management with Selective Arterial Clamping and Robotic Enucleation

The Bosniak classification of renal cysts aims to provide a probabilistic risk assessment indicating the likelihood of malignancy from imaging findings. Originally designed to classify adult renal cysts based on computed tomography findings, the Bosniak classification has been extended to pediatric patients, with some adjustments made with the aim of accommodating magnetic resonance imaging (MRI) and ultrasonography (US). Bosniak IV lesions are rare in adolescents, indicating localized renal cell carcinoma and requiring surgical intervention. In contrast, Bosniak III lesions can be treated conservatively, although there is a lack of specific guidelines on their management. We present a case of a 14-year-old boy with a Bosniak III lesion, which was incidentally detected during the US evaluation of a left varicocele. After a 12-month follow-up, MRI revealed progression to a Bosniak IV cyst. Robot-assisted tumor enucleation was performed with selective artery clamping when the patient was 15. Histopathology showed tubulocystic renal cell carcinoma without adverse features. Immunocytochemistry supported a favorable prognosis of this rare tumor (<1% of renal tumor), thus obviating the need for adjuvant treatment. At the 18-month follow-up, no recurrence or distant metastasis were observed. This case highlights the importance of an aggressive treatment in persistent Bosniak III and Bosniak IV renal cysts in children and adolescents and the necessity to offer a nephron-sparing surgery.

Assessment of temporal changes in glomerular filtration rate following clamp ischemia in male and female rats using transcutaneous FITC-sinistrin clearance

Warm arterial clamping with reperfusion in rats is a commonly utilized model of ischemic kidney injury (IRI). Traditionally, changes in plasma creatinine or creatinine clearance have been utilized to assess kidney function in this model. A limitation of these approaches, however, is that changes in plasma creatinine are relatively slow to occur, resulting in low temporal fidelity. This limits our ability to relate changes in kidney function to histo-pathological changes observed during reperfusion of the kidneys. Transcutaneous assessment of FITC-sinistrin clearance enables accurate, repeated measurement of glomerular filtration rate in conscious animals over short segments of time (hours) without drawing blood. The goal of the current study was to characterize temporal changes in renal function in male and female rats after reperfusion from bi-lateral warm arterial clamp ischemia using transcutaneous FITC-sinistrin clearance. Our study was performed in age matched male (n=8) and female (n=5) Sprague Dawley rats (12-20wks of age). FITC sinistrin clearance was measured by affxing a miniaturized transcutaneous measurement device between the shoulder blades (MediBeacon) of rats. 50mg/kg of FITC-sinistrin was then injected i.v via the tail vein and the device allowed to record for ~3 hours. Measurements were taken either at pre-surgery (baseline), 1-3 hours, 24 hours or 7 days following reperfusion of the kidneys from warm bilateral arterial clamp ischemia. For the ischemic surgery, animals were anesthetized with isoflurane (2-5%, 95% O2) and the right and left kidneys were accessed by flank incisions. After being exposed, the renal arteries were separated from the renal veins via dissection. Both renal arteries were then clamped with microserrefines for 45 minutes. After the ischemic period, the clamps were removed, allowing blood flow to be restored to the kidneys. Body temperature was measured via a rectal probe and maintained at 37°C throughout the procedure by a servo-controlled heating table and UV heating lamp. The wounds were then closed, and the animals allowed to recover. Buprenorphine was administered as an analgesic. For each measurement, the ½ life of FITC sinistrin was determined using a 1-compartment model (MB Lab software) and glomerular filtration rate (GFR) per 100g of body weight rate calculated. Baseline GFR was 0.94±0.03ml/min/100g in males and 1.09±0.02/min/100g in females (PTTEST=0.04). Following 45 minutes of warm bilateral arterial ischemia and reperfusion, GFR fell to 0.24±0.08ml/min/100g in male and 0.36±0.15ml/min/100g in females within 1-3 hours of reperfusion. At 24 hours of reperfusion, GFR averaged 0.06±0.03ml/min/100g in males and 0.28±0.16ml/min/100g in females. GFR recovered in males and females by 7 days of reperfusion averaging 0.86±0.10ml/min/100g in males and 0.83±0.00ml/min/100g in females. There was no significant difference between FITC-sinistrin clearance between males and females at any time point after IRI. Our data indicate that most of the reduction in GFR is present immediately after releasing the clamp. This is consistent with continued vascular disturbances mediating the initial decline in glomerular filtration rate in this model (i.e. vasospasm). The absence of sex differences in GFR decline using this method suggests that sex-differences detected using plasma creatinine may be, at least in part, secondary to the more rapid production of creatinine in males than in females or greater baseline filtration/body weight ratio in females compared to males rather than differences in renal function decline to ischemia. American Heart Association Transformational Project Award 970585 to Paul O'Connor. 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.

The severity of lower urinary tract symptoms during the postoperative period as a factor in choosing an approach to surgical treatment for large prostate hyperplasia: holmium enucleation of the prostate (HoLEP) vs laparoscopic simple prostatectomy

Introduction. Analysis of complications after transurethral surgery for benign prostate hyperplasia (BPH) demonstrates that 20 – 30% of patients require prolonged postoperative treatment for severe lower urinary tract symptoms (LUTS) despite improvements in technology and surgical techniques. These complications play a significant role in reducing the quality of life of patients in the postoperative period. Severe storage symptoms and urgent urinary incontinence represent significant challenges in the postoperative phase when performing laser enucleation surgery. There are also limits to standard approaches to perform laparoscopic prostatectomy, which requires the development of improved techniques.Objective. To conduct a comparative assessment of the postoperative dynamics of LUTS in groups undergoing holmium laser enucleation of the prostate (HoLEP), a standard Millin laparoscopic simple prostatectomy (LSP), and a modified LSP.Materials & Methods. This multicenter study included 439 patients who were randomly assigned to 3 groups depending on the surgical treatment technique used for bladder outlet obstruction associated with large-volume BPH: the HoLEP group (n = 151), the standard Millin LSP (n = 142) and the modified LSP, combined with temporary clamping of the internal iliac arteries and vesicourethral anastomosis (n = 146). The main criterion assessed during six-months follow-up was the severity of LUTS on the IPSS scale (obstructive and irritative components). Complications that developed during the postoperative observation period were recorded.Results. A lower severity of LUTS was revealed in the group of the modified LSP compared to the standard LSP and HoLEP (p = 0.041 and p = 0.001, respectively). The average irritative component of IPSS was significantly lower in the modified LSP group compared to the standard LSP and HoLEP (p = 0.032 and p = 0.001, respectively). The observed trend continued to the third month after surgery. Comparison of changes in symptom severity six months after surgery demonstrated a significant advantage for the modified LSP both compared to HoLEP (p = 0.017) and a standard LSP (p = 0.032). All three groups showed comparable significant improvements in quality of life.Conclusion. The severity of postoperative storage symptoms is a limitation of HoLEP use, whereas the standard LSP is associated with lower severity of LUTS. The authors' modification of the LSP has the potential to reduce the severity of storage symptoms in patients for up to three months after surgery, and is associated with a low rate of urge incontinence.

Bailout Distal Internal Carotid Artery Stenting after Carotid Endarterectomy: Indications, Technique, and Outcomes

Distal internal carotid artery (ICA) stenting may be employed as a bailout maneuver when an inadequate end point or clamp injury is encountered at the time of carotid endarterectomy (CEA) in a surgically inaccessible region of the distal ICA. We sought to characterize the indications, technique, and outcomes for this infrequently encountered clinical scenario. We performed a retrospective review of all patients who underwent distal ICA stenting at the time of CEA at our institution between September 2008 and July 2022. Procedural details and postoperative follow-up were reviewed for each patient. Six patients were identified during the study period. All were male with an age range of 63 to 82years. Five underwent carotid revascularization for asymptomatic carotid artery stenosis, and one patient was treated for amaurosis fugax. Three patients were on dual antiplatelet therapy preoperatively, whereas 2 were on aspirin monotherapy, and one was on aspirin and low-dose rivaroxaban. Five patients underwent CEA with patch angioplasty, and one underwent eversion CEA. The indication for stenting was distal ICA dissection due to clamp or shunt injury in 2 patients and an inadequate distal ICA end point in 4 patients. In all cases, access for stenting was obtained under direct visualization within the common carotid artery, and a standard carotid stent was deployed with its proximal aspect landing within the endarterectomized site. Embolic protection was typically achieved via proximal common carotid artery and external carotid artery clamping for flow arrest with aspiration of debris before restoration of antegrade flow. There was 100% technical success. Postoperatively, 2 patients were found to have a cranial nerve injury, likely occurring due to the need for high ICA exposure. Median length of stay was 2days (range 1-7days) with no instances of perioperative stroke or myocardial infarction. All patients were discharged on dual antiplatelet therapy with no further occurrence of stroke, carotid restenosis, or reintervention through a median follow-up of 17months. Distal ICA stenting is a useful adjunct in the setting of CEA complicated by inadequate end point or vessel dissection in a surgically inaccessible region of the ICA and can minimize the need for high-risk extensive distal dissection of the ICA in this situation.