Misra, Sanjay

Background— Atherosclerotic renal artery stenosis reduces renal blood flow (RBF) and amplifies stenotic kidney hypoxia. Revascularization with percutaneous transluminal renal angioplasty (PTRA) and stenting often fails to recover renal function, possibly because of ischemia/reperfusion injury developing after PTRA. Elamipretide is a mitochondrial-targeted peptide that binds to cardiolipin and stabilizes mitochondrial function. We tested the hypothesis that elamipretide plus PTRA would improve renal function, oxygenation, and RBF in patients with atherosclerotic renal artery stenosis undergoing PTRA. Methods and Results— Inpatient studies were performed in patients with severe atherosclerotic renal artery stenosis scheduled for PTRA. Patients were treated before and during PTRA with elamipretide (0.05 mg/kg per hour intravenous infusion, n=6) or placebo (n=8). Stenotic kidney cortical/medullary perfusion and RBF were measured using contrast-enhanced multidetector CT, and renal oxygenation by 3-T blood oxygen level−dependent magnetic resonance imaging before and 3 months after PTRA. Age and basal glomerular filtration rate did not differ between groups. Blood oxygen level−dependent imaging demonstrated increased fractional hypoxia 24 hours after angiography and stenting in placebo (+47%) versus elamipretide (−6%). These were reverted to baseline 3 months later. Stenotic kidney RBF rose (202±29–262±115 mL/min; P =0.04) 3 months after PTRA in the elamipretide-treated group only. Over 3 months, systolic blood pressure decreased, and estimated glomerular filtration rate increased ( P =0.003) more in the elamipretide group than in the placebo group ( P =0.11). Conclusions— Adjunctive elamipretide during PTRA was associated with attenuated postprocedural hypoxia, increased RBF, and improved kidney function in this pilot trial. These data support a role for targeted mitochondrial protection to minimize procedure-associated ischemic injury and to improve outcomes of revascularization for human atherosclerotic renal artery stenosis. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT01755858.

Atherosclerotic renovascular disease (RVD) reduces renal blood flow (RBF) and GFR and accelerates poststenotic kidney (STK) tissue injury. Preclinical studies indicate that mesenchymal stem cells (MSCs) can stimulate angiogenesis and modify immune function in experimental RVD. We assessed the safety and efficacy of adding intra-arterial autologous adipose-derived MSCs into STK to standardized medical treatment in human subjects without revascularization. The intervention group ( n =14) received a single infusion of MSC (1.0 × 10 5 or 2.5 × 10 5 cells/kg; n =7 each) plus standardized medical treatment; the medical treatment only group ( n =14) included subjects matched for age, kidney function, and stenosis severity. We measured cortical and medullary volumes, perfusion, and RBF using multidetector computed tomography. We assessed tissue oxygenation by blood oxygen level–dependent MRI and GFR by iothalamate clearance. MSC infusions were well tolerated. Three months after infusion, cortical perfusion and RBF rose in the STK (151.8–185.5 ml/min, P =0.01); contralateral kidney RBF increased (212.7–271.8 ml/min, P =0.01); and STK renal hypoxia (percentage of the whole kidney with R2*>30/s) decreased (12.1% [interquartile range, 3.3%–17.8%] to 6.8% [interquartile range, 1.8%–12.9%], P =0.04). No changes in RBF occurred in medical treatment only subjects. Single-kidney GFR remained stable after MSC but fell in the medical treatment only group (−3% versus −24%, P =0.04). This first-in-man dose-escalation study provides evidence of safety of intra-arterial infusion of autologous MSCs in patients with RVD. MSC infusion without main renal artery revascularization associated with increased renal tissue oxygenation and cortical blood flow.

Vascular access dysfunction remains a major cause of morbidity and mortality in hemodialysis patients. At present there are few effective therapies for this clinical problem. The poor understanding of the pathobiology that leads to arteriovenous fistula (AVF) and graft (AVG) dysfunction remains a critical barrier to development of novel and effective therapies. However, in recent years we have made substantial progress in our understanding of the mechanisms of vascular access dysfunction. This article presents recent advances and new insights into the pathobiology of AVF and AVG dysfunction and highlights potential therapeutic targets to improve vascular access outcomes.

Abstract Rationale There is sparse published literature on the causes and outcomes of hospitalization of patients with hereditary hemorrhagic telangiectasia (HHT). Objectives To evaluate rates of various complications, comorbidities, and in-hospital outcomes of patients with HHT using a large, multihospital inpatient database. Methods We identified patients with HHT in the U.S. Nationwide Inpatient Sample between 2000 and 2012. Rates of hemorrhagic, neurological, hepatic, and cardiopulmonary complications among hospitalized patients with HHT were evaluated. We also studied procedure use rates for blood transfusion, endoscopy, and epistaxis treatment. Hospitalization outcomes, including in-hospital mortality, discharge status, charges, and length of stay, were evaluated. Measurements and Main Results: We identified 10,293 patients with HHT. The mean age of the HHT population was 60.7 years. Sixty percent of patients were female. More than 75% of HHT hospitalizations occurred in those older than 50 years of age. Patients with HHT had high rates of bleeding-related complications, including anemia (53.3%), epistaxis (16.2%), and gastrointestinal bleeding (10.8%). Overall, bleeding complications accounted for 62.7% of HHT-related complications. Thirty-eight percent of hospitalized patients with HHT received one or more transfusions of a blood product. Cardiopulmonary complications were present in 41.0% of the cases. Congestive heart failure was the second most common individual complication among patients with HHT, affecting 19.9% of patients. The in-hospital mortality rate was 1.9%. Conclusions In this large, nationwide study, we found that nearly two-thirds of patients hospitalized with HHT experienced a bleeding-related complication. Nearly 40% of hospitalized patients with HHT required transfusion of blood products. Cardiopulmonary complications, including congestive heart failure, were the second most common complication. The high burden of bleeding-related complications points to a significant unmet clinical need for these patients.

Nanoparticles emerged as carriers of promising diagnostic and therapeutic molecules due to their unique size, injectability, and potential to sustainably release molecular cargos.