Lerman, Amir

Abstract Endothelial dysfunction can be regarded as the earliest feature of vascular aging and may occur in individuals without traditional risk factors for cardiovascular disease. Once present, endothelial dysfunction is known to increase the risk for atherosclerosis, cardiovascular diseases and complications such as stroke or death. Identification of individuals with early features of vascular aging remains challenging and has fuelled investigative efforts to associated biologic, imaging, and digital markers with endothelial dysfunction. This review highlights emerging and traditional methods to identify patients with early endothelial dysfunction and summarizes available and experimental therapies aimed at mitigating the vascular aging process.

Abstract Importance Mesenchymal stromal cells (MSCs) possess therapeutic properties that mediate repair. Obesity impairs MSC functionality and therapeutic efficacy, possibly by eliciting dynamic modifications of epigenetic markers, like 5-hydroxymethylcytosine (5hmC). Objective We hypothesized that human obesity alters the 5hmC landscape and anti-inflammatory capacity of adipose tissue-derived MSCs to activate the prominent inflammatory signaling mediator Interleukin (IL)-1β. Design, Setting, Participants, Intervention Adipose tissue samples were collected from obese and lean individuals (body mass index ≥30 or <30 kg/m2, respectively, n = 11 each) during weight-loss or kidney donation surgery. Main Outcomes and Measures MSCs were harvested and analyzed for 5hmC profiles (MeDIP-seq) and mRNA expression (RNA-seq) (n = 5 each). Subsequently, MSCs or a vehicle were injected into mice, (n = 6 each) and two-weeks later, kidneys were evaluated using in-vivo magnetic resonance imaging and ex vivo studies. The role of IL-1β was then studied in-vitro in MSC-induced immunomodulation using siRNA in macrophages. Results Compared to MSC from lean patients, obese-MSC genes showed 2087 differential 5hmC modifications and 175 differential mRNA expression. Among them, 14 genes with overlapping alterations were involved in regulation of cytokine production, prominently IL-1β. Injecting obese MSCs elevated renal expression of IL-1β and M1 macrophage count but lowered kidney perfusion. Silencing IL-1β in obese-MSCs in vitro reduced M1 phenotype switching in co-incubated macrophages. Conclusions and Relevance Obesity induces epigenetic and gene expression changes in MSCs, particularly in IL-1β, associated with impaired anti-inflammatory functionality of MSCs. Targeting IL-1β could be a useful therapeutic approach to modulate the decline in MSC functionality resulting from obesity.

Abstract Background and Aims Invasive coronary function testing (CFT) identifies coronary vasomotor disorders in up to 90% of patients with angina with non-obstructive coronary arteries (ANOCA). The ILIAS ANOCA trial hypothesized that routine ad hoc CFT would be feasible, safe, and effective in providing an early, comprehensive diagnosis. Additionally, it was anticipated that combining CFT with a disease-specific treatment protocol would significantly improve quality of life in ANOCA patients compared with standard care. Methods After excluding patients with obstructive coronary artery disease (CAD) during clinically indicated invasive coronary angiography (ICA), eligible patients underwent CFT and were randomized to either the standard care group, where CFT results remained blinded, or the intervention group, where CFT results were disclosed along with a tailored medical therapy protocol. The primary outcome was the mean difference in the within-subject change in Seattle Angina Questionnaire summary score (SAQSS) between groups from baseline to a follow-up of 6 months. The trial is registered with the International Clinical Trials Registry Platform (NL-OMON20739). Results A total of 255 patients consented, of whom 153 patients (60%) without CAD underwent CFT and were randomized 1:1 to the standard care (n = 76) or intervention group (n = 77). All CFT procedures were successful without adverse events. A vasomotor disorder was identified in 120 patients (78%). At 6-month follow-up, the SAQSS improved significantly in the intervention group compared with the control group, with an intervention effect of 9.4 units (95% confidence interval 3.9–14.9, P = .001). There were no major adverse cardiac events at the 6-month follow-up. Conclusions Routine CFT during the initial ICA was feasible, safe, and had high diagnostic yield. Implementing a pragmatic CFT protocol combined with a disease-specific treatment protocol significantly improved disease-related quality of life in patients with ANOCA compared with standard care.

Endothelial progenitor cells (EPCs) constitute a promising focus for research in regenerative medicine. These cells originate from the bone marrow and other circulating hematopoietic cells and regulate tissue regeneration and vascular integrity. EPC mobilization serves for neovascularization and re-endothelialization after injury in multiple organ systems, including the renal and cardiovascular systems. Both their number and function may vary in disease states such as CKD, depending on severity, comorbid conditions, and other factors. Therefore, circulating EPC count and function have been proposed as markers for vascular health, and their mobilization or replenishment may offer a potential therapy. Delivery of EPCs has shown success in repairing injured kidneys in animal models of both chronic and AKIs. This approach may be limited by EPC heterogeneity and incomplete characterization that may be addressed by standardization, engineering, or combination with other therapies. The aim of this article was to review the current state and recent advances in our understanding of the role of EPCs in homeostasis and conditions that may lead to their dysregulation in kidney diseases.

Abstract Renal artery stenosis (RAS) is the leading cause of secondary hypertension worldwide. However, current medical and surgical treatment modalities provide minimal benefits for kidney injury. Recent preclinical RAS models have demonstrated promising potential of human mesenchymal stem cells (MSC) and their daughter extracellular vesicles (EV) in improving murine renal function and attenuating inflammation. However, the extent and mechanisms underlying immune rejection of xenogeneic MSCs or EVs are yet undetermined. Therefore, adipose tissue was harvested from adult healthy patients. Adipose-derived MSCs were extracted and cultured, and EVs were isolated from their supernatants via ultra-centrifugation. Then, mice randomly assigned to RAS or sham surgery were divided into 6 groups: sham surgery, RAS, sham + MSC, RAS + MSC, sham + EV, and RAS + EV. Two weeks after intra-aortic injection of MSCs (5 × 105) or EVs (20 µg protein), we compared the intrarenal T-cell and macrophage accumulation, splenic B-cell numbers, circulating cytokines and anti-human antibodies levels among the groups. MSCs and EVs did not influence intrarenal immune cell infiltrations. However, MSCs significantly increased circulating anti-human antibodies. In the spleen, RAS + EV mice showed higher memory IgM+ B-cells but reduced CD19+ B-cells compared to RAS + MSC. In vitro T-cell recall assay showed that both MSCs and EVs exhibited reduced IFN-γ release upon re-stimulation, indicating an immunosuppressive effect. Therefore, xenogeneic MSCs induced a greater humoral response in mice, while EVs triggered a splenic cellular response, but neither elicits discernible kidney rejection. Our results provide key insights into the immunomodulatory mechanisms of MSCs and EVs and immune mechanisms underlying xenograft rejection.

Background A subset of individuals with major depressive disorder (MDD) have a high burden of cardiovascular risk factors and cerebral small‐vessel disease, implicating vascular disease in the development of depression. Cross‐sectional studies demonstrate a link between endothelial dysfunction and MDD, but the prospective association between peripheral endothelial dysfunction (PED) and an incident diagnosis of MDD is unknown. Methods and Results Patients undergoing a baseline assessment of cardiovascular risk were evaluated for PED using reactive hyperemia–peripheral arterial tonometry (≤1.8 consistent with PED). Patient medical records were reviewed to identify those who underwent a formal clinical evaluation of MDD after the index PED evaluation. The frequency of PED was compared in those with and without MDD. Logistic regression analyses were performed to assess the association between baseline PED and incident MDD. Between January 2006 and December 2020, 1614 patients underwent testing for PED. Four hundred eighty‐four (30.1%) patients underwent a formal evaluation for MDD after (0–15 years) the index procedure (mean±SD age, 52.8±13.8 years; 65.2% women). Of these, 157 (32.4%) had PED and 108 (31.0%) were diagnosed with MDD. Individuals with MDD had a higher frequency of PED (40.2% versus 30.2%; P =0.034) compared with those without MDD. In multivariable analyses, PED was significantly associated with MDD (odds ratio, 2.3 [95% CI, 1.4–3.8]; P <0.001). Conclusions PED is significantly associated with incident MDD. Thus, PED may be a useful marker to identify individuals at increased risk of depression who may benefit from more frequent and earlier management strategies.

Positive remodeling (PR) is an atherosclerotic plaque feature defined as an increase in arterial caliber at the level of an atheroma, in response to increasing plaque burden. The mechanisms that lead to its formation are incompletely understood, but its role in coronary atherosclerosis has major clinical implications. Indeed, plaques with PR have elevated risk of provoking acute cardiac events. Hence, PR figures among the high-risk plaque features that cardiac imaging studies should report. This review aims to provide an overview of the current literature on coronary PR. It outlines the pathophysiology of PR, the different techniques used to assess its presence, and the imaging findings associated to PR, on both noninvasive and invasive studies. This review also summarizes clinical observations, trials, and studies, focused on the impact of PR on clinical outcome.

Background Myocardial bridging (MB) is accompanied by the dynamic extravascular compression of epicardial coronary arteries, leading to intracoronary hemodynamic disturbance with abnormal coronary flow profiles. We aimed to evaluate the prognostic implications of resistive reserve ratio (RRR), a composite measure of flow and pressure parameters that represents the vasodilatory capacity of the coronary arteries, in patients with angina with nonobstructive coronary artery disease (ANOCA) and MB, in comparison with coronary flow reserve (CFR). Methods and Results In this retrospective cohort study, we included patients with ANOCA who underwent coronary reactivity testing, where MB was identified by transient constriction in coronary artery segments between systole and diastole. Abnormal CFR and RRR were defined as <2.5 and <2.62, respectively. Major adverse cardiac events, including cardiovascular death, stroke, myocardial infarction, heart failure, and late revascularization, served as outcomes. Among 1251 patients with ANOCA, 191 (15.3%) had MB. The prevalence of abnormal CFR or RRR was not significantly different between patients with and without MB ( P =0.144 and P =0.398, respectively). Over a median follow‐up time of 6.9 years, abnormal RRR predicted major adverse cardiac events in patients with MB (hazard ratio [HR], 4.38 [95% CI, 1.71–11.21]; P =0.002) and without MB (HR, 1.91 [95% CI, 1.38–2.64]; P <0.001). Abnormal CFR predicted major adverse cardiac events in patients without MB (HR, 2.15 [95% CI, 1.54–3.00]; P <0.001), whereas it was not predictive of major adverse cardiac events in patients with MB (HR, 2.29 [95% CI, 0.93–5.65]; P =0.073). Conclusions In patients with ANOCA and MB, impaired RRR was superior to impaired CFR in distinguishing patients at a higher risk of future adverse events, suggesting that RRR may serve as a risk stratification tool in patients with MB and ANOCA.

Key Points Renovascular disease impairs the capacity of human adipose tissue–derived mesenchymal stem/stromal cells to repair ischemic murine kidneys. miR-378h modulated the capacity of renovascular disease adipose tissue–derived mesenchymal stem/stromal cells to repair ischemic kidneys in vivo . Background Renovascular disease leads to renal ischemia, hypertension, and eventual kidney failure. Autologous transplantation of adipose tissue–derived mesenchymal stem/stromal cells (MSCs) improves perfusion and oxygenation in stenotic human kidneys, but associated atherosclerosis and hypertension might blunt their effectiveness. We hypothesized that renovascular disease alters the human MSC transcriptome and impairs their reparative potency. Methods MSCs were harvested from subcutaneous abdominal fat of patients with renovascular disease and healthy volunteers ( n =3 each), characterized and subsequently injected (5×10 5 /200 μ l) into mice 2 weeks after renal artery stenosis or sham surgery ( n =6/group). Two weeks later, mice underwent imaging and tissue studies. MSCs from healthy volunteers and in those with renovascular disease were also characterized by mRNA/microRNA (miRNA) sequencing. Based on these, MSC proliferation and mitochondrial damage were assessed in vitro before and after miRNA modulation and in vivo in additional renal artery stenosis mice administered with MSCs from renovascular disease pretreated with miR-378h mimic ( n =5) or inhibitor ( n =4). Results MSCs engrafted in stenotic mouse kidneys. Healthy volunteer MSCs (but not renovascular disease MSCs) decreased BP, improved serum creatinine levels and stenotic-kidney cortical perfusion and oxygenation, and attenuated peritubular capillary loss, tubular injury, and fibrosis. Genes upregulated in renovascular disease MSCs versus healthy volunteer MSCs were mostly implicated in transcription and cell proliferation, whereas those downregulated encoded mainly mitochondrial proteins. Upregulated miRNAs, including miR-378h, primarily target nuclear-encoded mitochondrial genes, whereas downregulated miRNAs mainly target genes implicated in transcription and cell proliferation. MSC proliferation was similar, but their mitochondrial structure and reparative function both in vivo and in vitro improved after miR-378h inhibition. Conclusions Renovascular disease impaired the reparative capacity of human MSCs, possibly by dysregulating miR-378h that targets mitochondrial genes. Podcast This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2024_08_21_ASN0000000000000440.mp3

Background Coronary microvascular dysfunction (CMD) represents an early functional characteristic of coronary vascular aging. Klotho (α‐klotho) is a circulating protein inversely linked to physiological aging. We examined low klotho as a potential marker for vascular aging in patients with CMD and no coronary artery disease. Methods and Results Patients undergoing nonurgent angiogram for chest pain who had no coronary artery disease underwent invasive coronary microvascular and endothelial function testing. CMD was defined by ≤50% increase in coronary blood flow (percentage change in coronary blood flow) in response to intracoronary acetylcholine or coronary flow reserve ≤2. Fresh arterial whole blood was used to analyze circulating endothelial progenitor cells with flow cytometry. Stored arterial plasma was used for klotho analysis by ELISA. Participants with CMD (n=62) were compared with those without CMD (n=36). Those with CMD were age 55±10 years (versus 51±11 years; P =0.07) and 73% women (versus 81%; P =0.38). Traditional risk factors for coronary artery disease were similar between groups. Patients with CMD had less klotho (0.88±1.50 versus 1.75±2.38 ng/mL; P =0.03), and the odds of low klotho in CMD were significant in a logistic regression model after adjusting for traditional cardiovascular risk factors (odds ratio [OR], 0.80 [95% CI, 0.636–0.996]; P =0.05). Higher klotho was associated with higher numbers of endothelial progenitor cells with vascular regenerative potential (CD34 + and CD34 + CD133 + KDR + ). Among a subgroup of patients with atherosclerotic cardiovascular disease risk <5% (n=58), CMD remained associated with lower klotho (OR, 0.80 [95% CI, 0.636–0.996]; P =0.047). Conclusions Klotho may be a biomarker for CMD and may be a therapeutic target for groups of patients without significant traditional cardiovascular risk.