Subsequent Ischemia Research Articles

Does the renal portal valve exist in a raptor species? A study aimed at further evaluating the mechanism of toxicity of diclofenac in vultures.

Diclofenac has been responsible for the deaths of millions of vultures on the Asian subcontinent. While the pathology of toxicity is well described, the mechanism of toxicity remains elusive. However, it was postulated that toxicity could be related to the unique avian renal vascular structure known as the renal portal valve and that that diclofenac altered valve functionality with subsequent renal ischaemia. While plausible, the valva renalis portalis has only been described in a small number of other bird species such as the chicken (Gallus domesticus), the domestic duck (Anas platyrhynchos domesticus) and ostrich (Struthio camelus) but not a raptor. The aim of this study was to evaluate the renal anatomy and related vasculature of the Cape griffon vulture (Gyps coprotheres) (CGV), a species sensitive to the toxic effects of diclofenac, using gross anatomy, histology and vascular casting. The vasculature of the vulture was found to be almost identical to that of the domestic chicken with the valva renalis portalis present in the v. iliaca externa between the v. renalis renalis cranialis and the v. renalis caudalus. The valve was ring-shaped with finger-like processes and histologically was composed of smooth muscle. The valve was also well vascularized and was associated with a nerve plexus. Based on the findings of this study, the proposed mechanism of toxicity is anatomically possible.

Safety and efficacy of direct Cardiac Shockwave Therapy in patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting (the CAST-HF trial): study protocol for a randomized controlled trial

BackgroundCoronary artery diseases (CAD) remains a severe socio-economic burden in the Western world. Coronary obstruction and subsequent myocardial ischemia result in progressive replacement of contractile myocardium with dysfunctional, fibrotic scar tissue. Post-infarctional remodeling is causal for the concomitant decline of left-ventricular function and the fatal syndrome of heart failure. Available neurohumoral treatment strategies aim at the improvement of symptoms. Despite extensive research, therapeutic options for myocardial regeneration, including (stem)-cell therapy, gene therapy, cellular reprogramming or tissue engineering, remain purely experimental. Thus, there is an urgent clinical need for novel treatment options for inducing myocardial regeneration and improving left-ventricular function in ischemic cardiomyopathy.Shockwave Therapy (SWT) is a well-established regenerative tool that is effective for the treatment of chronic tendonitis, long-bone non-union and wound-healing disorders. In preclinical trials, SWT regenerated ischemic myocardium via the induction of angiogenesis and the reduction of fibrotic scar tissue, resulting in improved left-ventricular function.Methods/designIn this prospective, randomized controlled, single-blind, monocentric study, 80 patients with reduced left-ventricular ejection fraction (LVEF≤ 40%) are subjected to coronary-artery bypass-graft surgery (CABG) surgery and randomized in a 1:1 ratio to receive additional cardiac SWT (intervention group; 40 patients) or CABG surgery with sham treatment (control group; 40 patients). This study aims to evaluate (1) the safety and (2) the efficacy of cardiac SWT as adjunctive treatment during CABG surgery for the regeneration of ischemic myocardium. The primary endpoints of the study represent (1) major cardiac events and (2) changes in left-ventricular function 12 months after treatment. Secondary endpoints include 6-min Walk Test distance, improvement of symptoms and assessment of quality of life.DiscussionThis study aims to investigate the safety and efficacy of cardiac SWT during CABG surgery for myocardial regeneration. The induction of angiogenesis, decrease of fibrotic scar tissue formation and, thus, improvement of left-ventricular function could lead to improved quality of life and prognosis for patients with ischemic heart failure. Thus, it could become the first clinically available treatment strategy for the regeneration of ischemic myocardium alleviating the socio-economic burden of heart failure.Trial registrationClinicalTrials.gov, ID: NCT03859466. Registered on 1 March 2019.

Penile calciphylaxis: A retrospective case-control study

Calciphylaxis is a rare disorder characterized by skin necrosis caused by calcium deposition within vessels, thrombosis, and subsequent tissue ischemia. Penile involvement may rarely occur. To identify risk factors, diagnosis, management, and mortality of patients with penile calciphylaxis. A retrospective medical record review was conducted of 16 patients with penile calciphylaxis treated at 2 large urban tertiary care centers between January 2001 and December 2019. A control group of 44 male patients with nonpenile calciphylaxis at the same institution was included. The median survival of patients with penile calciphylaxis was 3.8months (interquartile range, 27.0months). Mortality was 50% at 3months and 62.5% at 6months for penile calciphylaxis, and 13.6% at 3months and 29.5% at 6months for controls (P=.008). Patients with penile calciphylaxis were less likely to be obese (P=.04) but more likely to have hyperparathyroidism (P=.0003) and end-stage renal disease (P=.049). Retrospective study design and small sample size. This study further defines the disease course of penile calciphylaxis, which has high mortality. Imaging may be used to aid diagnosis. Risk factors include end-stage renal disease, hyperparathyroidism, and normal body mass index.

Myocardial Preconditioning by Intracoronary Adenosine before Elective Percutaneous Coronary Intervention (short term outcome)

Background and Purpose: Pre- and post-conditioning by transient episodes of ischemia render the myocardium more resistant to subsequent ischemia, a phenomenon known as ischemic pre-conditioning. This effect is thought to be partly mediated by endogenous adenosine. The aim of the study was to investigate the efficacy and safety of intracoronary adenosine on myocardial perfusion in patients schedule for elective percutaneous coronary intervention. Methods: A prospective observational comparative study of 120 patients with coronary artery disease scheduled for elective percutaneous coronary intervention. Patients were randomly to receive intracoronary adenosine (n = 60 ) or placebo (n= 60), both groups were compared regarding clinical risk factors electrocardiographic, echocardiographic, cardiac troponin ,C-reactive protein, angiographic variables and major adverse cardiac events. Results: Among clinical risk factors, smoking and obesity were significantly higher in placebo group. ECG data, echocardiographic data, Troponin data and myonecrosis were not statistically significant different between both groups before and after percutaneous coronary intervention, but high sensitive C-reactive protein was statistically significantly higher post percutaneous coronary intervention in placebo group. There was no statistically significant difference between both groups regarding percutaneous coronary intervention results, periprocedural complications and short term clinical outcome. Conclusion: Myocardial preconditioning by intracoronary adenosine in patients schedule for elective percutaneous coronary intervention is safe but did not provide any benefit in terms of decreasing periprocedural myonecrosis or improving short term clinical outcome. The elevation of high sensitive C-reactive protein is determined by more vessels manipulation by more pre dilation , post dilatation and more number of stents.

Targeting High Mobility Group Box 1 in Subarachnoid Hemorrhage: A Systematic Review.

Aneurysmal subarachnoid hemorrhage (aSAH) is a complex and potentially deadly disease. Neurosurgical clipping or endovascular coiling can successfully obliterate ruptured aneurysms in almost every case. However, despite successful interventions, the clinical outcomes of aSAH patients are often poor. The reasons for poor outcomes are numerous, including cerebral vasospasm (CVS), post-hemorrhagic hydrocephalus, systemic infections and delayed cerebral ischemia. Although CVS with subsequent cerebral ischemia is one of the main contributors to brain damage after aSAH, little is known about the underlying molecular mechanisms of brain damage. This review emphasizes the importance of pharmacological interventions targeting high mobility group box 1 (HMGB1)-mediated brain damage after subarachnoid hemorrhage (SAH) and CVS. We searched Pubmed, Ovid medline and Scopus for “subarachnoid hemorrhage” in combination with “HMGB1”. Based on these criteria, a total of 31 articles were retrieved. After excluding duplicates and selecting the relevant references from the retrieved articles, eight publications were selected for the review of the pharmacological interventions targeting HMGB1 in SAH. Damaged central nervous system cells release damage-associated molecular pattern molecules (DAMPs) that are important for initiating, driving and sustaining the inflammatory response following an aSAH. The discussed evidence suggested that HMGB1, an important DAMP, contributes to brain damage during early brain injury and also to the development of CVS during the late phase. Different pharmacological interventions employing natural compounds with HMGB1-antagonizing activity, antibody targeting of HMGB1 or scavenging HMGB1 by soluble receptors for advanced glycation end products (sRAGE), have been shown to dampen the inflammation mediated brain damage and protect against CVS. The experimental data suggest that HMGB1 inhibition is a promising strategy to reduce aSAH-related brain damage and CVS. Clinical studies are needed to validate these findings that may lead to the development of potential treatment options that are much needed in aSAH.

Refocusing the Brain: New Approaches in Neuroprotection Against Ischemic Injury.

A new era for neuroprotective strategies is emerging in ischemia/reperfusion. This has forced to review the studies existing to date based in neuroprotection against oxidative stress, which have undoubtedly contributed to clarify the brain endogenous mechanisms, as well as to identify possible therapeutic targets or biomarkers in stroke and other neurological diseases. The efficacy of exogenous administration of neuroprotective compounds has been shown in different studies so far. However, something must be missing to get these treatments successfully applied in the clinical environment. Here, the mechanisms involved in neuronal protection against physiological level of ROS and the main neuroprotective signaling pathways induced by excitotoxic and ischemic stimuli are reviewed. Also, the endogenous ischemic tolerance in terms of brain self-protection mechanisms against subsequent cerebral ischemia is revisited to highlight how the preconditioning has emerged as a powerful tool to understand these phenomena. A better understanding of endogenous defense against exacerbated ROS and metabolism in nervous cells will therefore aid to design pharmacological antioxidants targeted specifically against oxidative damage induced by ischemic injury, but also might be very valuable for translational medicine.

Factor V Leiden and superior mesenteric artery occlusion: A case study

Factor V Leiden (FVL) is an inherited condition that prolongs the clotting process; this subsequently places individuals at a higher risk of developing a thromboembolism. This case study will discuss a 41-year-old female who developed a superior mesenteric artery occlusion with subsequent small bowel ischaemia on a background of FVL. The discussion will illustrate the rarity of an arterial occlusion, the risk factors that are associated with an ischaemic small bowel, the implications of inheriting FVL and some of the associated social aspects of an ileostomy.

Abstract 65: Intrathecal Nicardipine for Cerebral Vasospasm Post Subarachnoid Hemorrhage - A Single Center Experience

Introduction: Cerebral vasospasm leading to delayed cerebral ischemia (DCI) is one of the most significant factors impacting functional outcome in patients diagnosed with non-traumatic subarachnoid hemorrhage (SAH). Effective treatment in this setting is lacking. We now report a single center retrospective cohort experience with intrathecal (IT) Nicardipine for this indication. Methods: All patients discharged between 2013-2017 diagnosed with non-traumatic SAH, either aneurysmal or idiopathic, were included in the analysis. Demographics, risk factors, clinical courses, radiological DCI, and functional outcomes were analyzed. Results: 1,085 patients were admitted with aneurysmal (n=796) or idiopathic (n=289) SAH. The mean age was 54.5±14.1 and 67.7% were women. Low grade hemorrhage (WFNS 1) was found in 42.4%, medium (WFNS 2-3) in 26.9%, and high grade (WFNS 4-5) in 30.7%. Cerebral vasospasm was diagnosed in 36.6% of the patients, and 85.4% of those received IT Nicardipine (n=339). Only 8.4% of all patients required angiography to treat vasospasm. TCD data was available for 159 patients who received IT Nicardipine. Treatment reduced mean velocities in all arteries within one day by 15.4% on average (p<0.01). This reduction was sustained for the duration of treatment. Nineteen patients (1.8%) suffered from bacterial ventriculitis, and no statistically significant correlation was noted between IT treatment and infection (OR 1.06 95%CI[0.42-2.7]). The incidence of radiological DCI, identified by blinded assement of imaging, was 9.4% and clinical DCI was 5.7%. In this cohort, 65.5% had a favorable functional outcome (mRS≤2) at 90 days. Conclusions: In a retrospective analysis, off-label IT Nicardipine is a safe and potentially effective treatment for cerebral vasospasm and prevention of the subsequent cerebral ischemia. Being the largest of its kind, this cohort could serve as a baseline for future clinical trial designs assessing IT Nicardipine safety and efficacy in a prospective, controlled fashion.

Operative treatment of dialysis associated steal syndrome: basilic vein graft applied for revision using distal inflow (RUDI) procedure

Introduction: Artificial arterio-venous fistula-induced steal syndrome and subsequent distal ischemia are one of the most serious complications of arterial-venous fistula (AVF) surgery, ranging from 1 to 8% of cases. Traditionally, the complication is difficult to treat without losing the fistula. Treatment options include ligature of the fistula, fistula banding, distal revascularization with interval ligation (DRIL), proximalisation of the arterial inflow (PAI), and revision using distal inflow (RUDI). We would like to present a case of a 45-year-old woman who has developed dialysis associated steal syndrome with necrosis on the left arm 5 months after a cubital AVF was created. In order to maintain her arterio-venous fistula, RUDI procedure was performed to eliminate ischemia. We used basilic vein graft for distal revision of the astomosis. As a result of the procedure, ischemic complaints ceased, dialysis did not need to be interrupted, no further vascular access was necessary. Distalization of arterial inflow (RUDI) is an easy-to-implement, good-performing method for which the use of vena basilica graft is a very obvious solution.

A caspase-6-cleaved fragment of Glial Fibrillary Acidic Protein as a potential serological biomarker of CNS injury after cardiac arrest.

Blood levels of Glial Fibrillary Acidic protein (GFAP) reflect processes associated with different types of CNS injury. Evidence suggests that GFAP is cleaved by caspases during CNS injury, hence positioning GFAP fragments as potential biomarkers of injury-associated processes. We set out to develop an assay detecting the neo-epitope generated by caspase-6 cleavage of GFAP (GFAP-C6), and to assess the ability of GFAP-C6 to reflect pathological processes in patients suffering a cardiac arrest and subsequent global cerebral ischemia. Anti-GFAP-C6 antibodies recognized their specific target sequence, and dilution and spike recoveries in serum were within limits of ±20% reflecting high precision and accuracy of measurements. Intra- and inter-assay CVs were below limits of 10% and 15%, respectively. Serological levels of GFAP-C6 were significantly elevated 72 hours after CA (Mean±SD) (20.39±10.59 ng/mL) compared to time of admission (17.79±10.77 ng/mL, p<0.0001), 24 hours (17.40±7.99 ng/mL, p<0.0001) and 48 hours (17.87±8.56 ng/mL, p<0.0001) after CA, but were not related to neurological outcome at day 180. GFAP-C6 levels at admission, 24, 48, and 72 hours after cardiac arrest correlated with two proteolytic fragments of tau, tau-A (r = 0.30, r = 0.40, r = 0.50, r = 0.53, p < 0.0001) and tau-C (r = 54, r = 0.48, r = 0.55, r = 0.54, p < 0.0001), respectively. GFAP-C6 levels did not correlate with other markers of CNS damage; total tau, NSE and S100B. In conclusion, we developed the first assay detecting a caspase-6 cleaved fragment of GFAP in blood. Increased levels at 72 hours after cardiac arrest as well as moderate correlations between GFAP-C6 and two other blood biomarkers of neurodegeneration suggest the ability of GFAP-C6 to reflect pathological processes of the injured brain. Investigations into the potential of GFAP-C6 in other types of CNS injury are warranted.

1461 Pseudomembranous Colitis, Bowel Ischemia, and Phentermine: A Case Report

INTRODUCTION: Pseudomembranous colitis, though classically associated with Clostridium difficile infection, can be a consequence of other disease processes including severe ischemic colitis. Several drugs have been proposed to predispose to colonic ischemia including the appetite suppressant phentermine. We present a case of pseudomembranous colitis from severe bowel ischemia that likely was compounded by concomitant phentermine use. CASE DESCRIPTION/METHODS: A 55-year-old obese Caucasian female with hypertension presented with a week of abdominal pain and progressively worsening diarrhea that had subsequently turned bloody. She was a former smoker. Medication history was significant for using a family member's weight loss medication Phentermine 37.5 mg daily for several days prior to developing gastrointestinal symptoms. At presentation she was mildly hypotensive needing fluid resuscitation and brief vasopressor support. Laboratory profile was significant for acute kidney injury with creatinine 8.86 mg/dl, lactic acid 3.2 mmol/L and white blood cell count 12.3 k/uL. A non-contrast CT abdomen showed findings suggestive of acute colitis involving the splenic flexure and descending colon (Figure 1). Supportive care and broad-spectrum antibiotics were continued. Multiple stool studies were negative for clostridium difficile infection, bacterial cultures, and assays for ova and parasites. Antineutrophil antibodies and antineutrophil cytoplasmic antibodies were negative as well. Flexible sigmoidoscopy revealed severe ulcerations covered by thick exudate of the rectum and sigmoid colon (Figure 2). Histopathology of biopsy specimens showed colonic mucosa with fibrinopurulent surface adherent exudate with abundant neutrophils consistent with pseudomembranous colitis (Figure 3). Patient recovered with supportive care alone and was subsequently discharged with instructions not to use Phentermine again. DISCUSSION: Our patient, with risks for vascular disease, had several days of abdominal pain with diarrhea. At the time of her initial hospital presentation, she was hypotensive likely from gastrointestinal volume loss. The inciting event for her colonic ischemia is unclear. Possibilities include Phentermine induced colonic ischemia that was further compounded by volume loss vs prodrome of gastroenteritis leading to volume loss and hypovolemia with subsequent colonic ischemia compounded by patient's Phentermine use. Phentermine use in this patient would have been contraindicated secondary to her vascular risk factors.

Cardiac Magnetic Resonance Stress Perfusion Imaging for Evaluation of Patients With Chest Pain

BackgroundStress cardiac magnetic resonance imaging (CMR) has demonstrated excellent diagnostic and prognostic value in single-center studies. ObjectivesThis study sought to investigate the prognostic value of stress CMR and downstream costs from subsequent cardiac testing in a retrospective multicenter study in the United States. MethodsIn this retrospective study, consecutive patients from 13 centers across 11 states who presented with a chest pain syndrome and were referred for stress CMR were followed for a target period of 4 years. The authors associated CMR findings with a primary outcome of cardiovascular death or nonfatal myocardial infarction using competing risk-adjusted regression models and downstream costs of ischemia testing using published Medicare national payment rates. ResultsIn this study, 2,349 patients (63 ± 11 years of age, 47% female) were followed for a median of 5.4 years. Patients with no ischemia or late gadolinium enhancement (LGE) by CMR, observed in 1,583 patients (67%), experienced low annualized rates of primary outcome (<1%) and coronary revascularization (1% to 3%), across all years of study follow-up. In contrast, patients with ischemia+/LGE+ experienced a >4-fold higher annual primary outcome rate and a >10-fold higher rate of coronary revascularization during the first year after CMR. Patients with ischemia and LGE both negative had low average annual cost spent on ischemia testing across all years of follow-up, and this pattern was similar across the 4 practice environments of the participating centers. ConclusionsIn a multicenter U.S. cohort with stable chest pain syndromes, stress CMR performed at experienced centers offers effective cardiac prognostication. Patients without CMR ischemia or LGE experienced a low incidence of cardiac events, little need for coronary revascularization, and low spending on subsequent ischemia testing. (Stress CMR Perfusion Imaging in the United States [SPINS]: A Society for Cardiovascular Resonance Registry Study; NCT03192891)

Ultrasound-guided access to the distal radial artery at the anatomical snuffbox for catheter-based vascular interventions: a technical guide.

Conventional radial access has been shown to have many advantages over the transfemoral approach. The risk of potential radial artery occlusion and subsequent hand ischaemia can be reduced further by accessing the vessel distally at the anatomical snuffbox, allowing maintenance of antegrade flow to the hand by the superficial palmar arch branch. Additional potential advantages of distal radial access in comparison to the conventional radial approach at the wrist include fewer puncture-site complications and faster post-procedural haemostasis as the vessel is very superficial. Furthermore, it provides another safe, non-femoral option for vascular access. The use of ultrasound guidance enables the operator to identify important anatomical landmarks and avoid injuring adjacent structures. We provide a detailed step-by-step guide for performing distal radial access using sonographic and anatomical correlation, thereby facilitating safe access and optimising technical success.

Integrative Multi-Omics Analysis Of Human Atherosclerosis Reveals An Intraplaque Bleeding Associated Network, Which Offers Better Prediction Of Disease Stage

Background and Aims: Initiation and progression of atherosclerotic lesions involve complex biological processes including lipid metabolism, inflammation, and hypoxia response pathways. Progressive lesion expansion and destabilization may predispose to acute plaque rupture and subsequent ischemia of downstream tissue in heart, brain or kidney. Unfortunately, a rigorous model to systematically and comprehensively describe the underlying mechanisms in plaque rupture is lacking.

Histologic Appearance of Iatrogenic Obstructive Hydrocephalus in the Fetal Lamb Model

Introduction: Documentation of histologic findings associated with congenital hydrocephalus in the fetal lamb model is a critical step in evaluating the efficacy of ventriculoamniotic shunting in the human fetus. Methods: Four fetal sheep had hydrocephalus induced at approximately 95 days’ gestation. Two co-twins remained as controls. The ewes were euthanized at term. The lamb brains were fixed in formalin, paraffin-embedded, stained, and analyzed for markers of neuropathology. Astrocytosis, microgliosis, and axonal loss were assessed with immunocytochemistry for glial fibrillary acidic protein, ionized calcium-binding adapter, and neurofilament/amyloid precursor protein, respectively. Cortical gray matter extracellular matrix was assessed with staining for the lectin Wisteria Floribunda agglutinin. Results: Hydrocephalic lamb brains demonstrated deep white matter damage with loss of projecting axonal tracts in regions physically distorted by hydrocephalus, similar to that seen in hydrocephalic humans. There was no evidence of abnormal neocortical neuronal migration; however, there was evidence for delayed maturation of the neocortical gray matter, possibly from increased intracerebral pressure and subsequent ischemia. Control lamb brains demonstrated none of the above findings. Conclusion: This histological approach can be used to further define the mechanism of brain damage associated with hydrocephalus and interpret the efficacy of ventriculoamniotic shunting on fetal lamb brain neuroanatomy.

GRK5‐mediated Exacerbation of Ischemic Heart Failure Involves Cardiac Immune and Inflammatory Responses

RATIONALECoronary artery disease and subsequent myocardial ischemia (MI) are the most common cause of heart failure (HF) in the US. G protein‐coupled receptor (GPCR) kinase 5 (GRK5) has been shown to be upregulated in failing human myocardium. While the canonical role of GRKs is to desensitize receptors via phosphorylation, GRK5 can also locate to the nucleus of cardiomyocytes where it exerts GPCR‐independent effects that promote maladaptive cardiac hypertrophy after hypertrophic stress. Despite numerous data indicating the importance of GRK5 in hypertrophy, it is still unknown if GRK5 has a role in ischemic heart disease.OBJECTIVEIn this study, we investigated the critical role that GRK5 plays after myocardial ischemic injury with a novel aspect being the regulation of immune and inflammatory responses including recruitment of immune cells to the injured heart.METHODS AND RESULTSCardiac‐specific GRK5 transgenic mice (Tg‐GRK5) and non‐transgenic littermate (NLC) control mice were subjected to MI. Tg‐GRK5‐HF mice showed decreased cardiac function (both global and segmental contractility), augmented left ventricular diameters/volumes and decreased survival rate compared to NLC‐HF mice. Heart weight (HW) to body weight or to tibia length ratios as well as mRNA expression of all major adverse remodeling‐associated biomarkers (ANF, BNP, b‐MHC) were increased in the TgGRK5‐HF compared to NLC‐HF. Cardiac fibrosis in the border zone (BZ) area as well as mRNA levels of Collagen‐1 (Col‐1), Col‐3, MMP2 and CTGF were higher in TgGRK5‐HF compared to NLC‐HF, strongly suggesting increased adverse remodeling. Cardiac inflammatory cytokines (IL‐6 and IL‐1beta), adhesion molecule (VCAM‐1) and chemokines (CCL2, CCL3, CCL5) were augmented in TgGRK5‐HF compared to NLC‐HF and contribute at least in part to increased immune cell recruitment in the heart. In fact, we found neutrophils/macrophages and T‐lymphocytes (T‐cells) respectively augmented at 4 days and 8 weeks after MI in both BZ and infarct zone. Interestingly, cardiac‐specific GRK2 transgenic mice did not show increased cardiac inflammation and chemokine production after MI when compared to NLC‐HF mice.CONCLUSIONSOur study shows that cardiac GRK5 has a detrimental effect during ischemic HF. GRK5 overexpression causes reduced cardiac function and increased immune cell recruitment/inflammation. Further, these results suggest GRK5 as a potential therapeutic target to limit HF development after ischemic injury.Support or Funding InformationThis work was supported by National Institutes of Health (NIH P01 HL091799, NIH R37 HL061690, NIH P01 HL075443 [Project 2]) to W.J.K. and American Heart Association (postdoctoral fellowship 17POST33660942) to C.d.L..This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Time and Temperature Dependent Ficoll Separation of Aged Whole Blood Neutrophils

Emerging clinical applications of bone marrow often require separation and purification of hematopoietic stem/progenitor cells (HSPC). Ficoll density gradient centrifugation is a well‐known and effective method for separating mononuclear cells in fresh blood and bone marrow to facilitate cell selection. Often these cell selection processes are performed in centralized locations, requiring transport and some amount of subsequent ischemia. As blood and bone marrow ages, neutrophil characteristics change causing interference in standard cell separations. Over time granulocytes degranulate and become less dense. Thus, degranulated granulocytes are no longer able to sediment through the Ficoll layer and they become trapped in the buffy coat with lymphocytes and HSPCs. Using blood as a surrogate, this study aims to define the critical time points of the degranulation process and its temperature dependence to optimize parameters of Ficoll separation for aged samples.Blood was collected from three healthy donors and stored at 4 and 20 °C. This experiment was repeated for an n of 2. At zero, three, and twenty‐four hours after collection, blood was centrifuged at 400g for 40 minutes with no acceleration or brake over a 1.077 g/ml Ficoll density gradient. The buffy coat and pellet were collected from each sample and characterized using flow cytometry. Cell marker CD45 was used to identify white blood cells of hematopoietic lineage. Cell marker CD66b was used to identify granulocytes. Results indicated that blood stored at 4 °C exhibited more degranulation of neutrophils compared to blood stored at 20 °C [Table 1]. After three hours, blood stored at 4 °C had more granulocytes trapped in the buffy coat following Ficoll density gradient centrifugation as compared to 20 °C. After twenty‐four hours, blood stored at 20 °C also failed to separate adequately.In conclusion, the results of this study indicate that neutrophil stability decreases rapidly following low temperature exposure, which impacts subsequent cell separation techniques and must be taken into account with hypothermic transport of samples intended for cell selection.Support or Funding InformationMarian University and Ossium HealthThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The Effect of Nitric Oxide on Remote Ischemic Preconditioning in Renal Ischemia Reperfusion Injury in Rats.

Although remote ischemic preconditioning (RIPC) is an organ-protective maneuver from subsequent ischemia reperfusion injury (IRI) by application of brief ischemia and reperfusion to other organs, its mechanism remains unclear. However, it is known that RIPC reduces the heart, brain, and liver IRI, and that nitric oxide (NO) is involved in the mechanism of this effect. To identify the role of NO in the protective effect of RIPC in renal IRI, this study examined renal function, oxidative status, and histopathological changes using N-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor. Remote ischemic preconditioning was produced by 3 cycles of 5 minutes ischemia and 5 minutes reperfusion. Blood urea nitrogen, creatinine (Cr), and renal tissue malondialdehyde levels were lower, histopathological damage was less severe, and superoxide dismutase level was higher in the RIPC + IRI group than in the IRI group. The renoprotective effect was reversed by L-NAME. Obtained results suggest that RIPC before renal IRI contributes to improvement of renal function, increases antioxidative marker levels, and decreases oxidative stress marker levels and histopathological damage. Moreover, NO is likely to play an important role in this protective effect of RIPC on renal IRI.

English

INTRODUCTION: Acute kidney injury following receipt of iodinated contrast (CI-AKI) has been referred to as contrast induced nephropathy. There are various preventive measures for CI-AKI like 1. use of less nephrotoxic contrast agents, 2. use of pharmacological agents to counteract the toxic effects of contrast media, 3. administration of IV fluids to expand the intravascular space and enhance dieresis. This study shows whether ischemic preconditioning, transient brief episodes of ischemia before a subsequent prolonged ischemia / reperfusion injury is useful to reduce the incidence of CI-AKI. AIMS AND OBJECTIVES: To assess if remote ischemic preconditioning reduces the incidence of CI-AKI in patients with STEMI undergoing coronary angiogram. MATERIALS & METHODS: This is a prospective, single blind, randomized, sham-controlled parallel group study conducted among 100 randomly selected patients who are admitted in Govt. Rajaji Hospital, Madurai with STEMI. Patients are divided into two groups (test and control). Control group will undergo CAG without RIPC and those in the test group will undergo CAG after undergoing RIPC by three cycles of ischemia/ reperfusion of upper arm, achieved by 5 minute cuff inflation at 20 mm Hg above SBP followed by 5 minutes of complete cuff deflation. Both sets of patients are hydrated with normal saline infusion. Necessary haematological, biochemical, radiological investigations are performed and serum creatinine will be serially monitored in the next 72 hrs. RESULTS: Of the 50 patients in the control group 18 developed CI-AKI and of the 50 in test group 8 developed CI-AKI. This shows that RIPC was associated with a lower incidence of CIAKI and the difference was statistically significant. CONCLUSION: Not only was the incidence of CIAKI lower in RIPC group, but the mean rise in serum creatinine was also lower which would further reduce the duration of hospital stay and short term mortality. Thus RIPC can serve as a cost efficient tool in the lowering of occurrence of CI-AKI in patients undergoing contrast imaging.

Abstract TP541: CT Angiography Leptomeningeal Collateral Assessment for Vasospasm in Patients With Aneurysmal Subarachnoid Hemorrhage

Introduction: Although leptomeningeal collaterals in acute large vessel occlusion have been well studied with respect to core infarct volume and risk of hemorrhagic conversion, their association with vasospasm in the setting of subarachnoid hemorrhage is less clear. Our purpose is to investigate the utility of leptomeningeal collateral scoring on CTA of patients presenting with aneurysmal subarachnoid hemorrhage (aSAH). Methods: IRB-approved retrospective review of 122 consecutive patients with angiographic vasospasm after surgical or endovascular repair of ruptured intracranial aneurysm. A 5-point grading scale was adapted from Christoforidis et al. to compare leptomeningeal collateral scores on CTA with digital subtraction agiography (DSA) at presentation. An independent chart review was performed to correlate imaging with clinical markers of symptomatic vasospasm and delayed cerebral ischemia. Results: Of the 122 initial patients with vasospasm, 16 demonstrated unilateral high-grade M1 stenosis in the absence of a second ipsilateral large vessel stenosis, 11 of which (68.8%) developed cerebral infarction secondary to vasospasm. Leptomeningeal collateral scoring on CTA at presentation agreed with DSA scores in half of patients (n=8), underestimated collaterals by 1 point in 7 patients, and overestimated their presence by 1 point in a single case. Conclusion: Characterization of leptomeningeal collaterals in patients with aSAH may better predict subsequent vasospasm and cerebral ischemia. Our initial findings in cases of isolated severe M1 vasospasm highlight the potential value of collateral scoring on CTA at presentation. Collateral scoring on CTA correlates with DSA in half of cases, however further work is indicated to elucidate the technical factors contributing to 1-point underestimation in the other half cases. Christoforidis, G.A., et al., Predictors of hemorrhage following intra-arterial thrombolysis for acute ischemic stroke: the role of pial collateral formation. AJNR Am J Neuroradiol, 2009. 30 (1): p. 165-70.