Behfar, Atta

Background: Pulmonary vascular resistance (PVR) is commonly considered to reflect opposition to lung blood flow caused by the arteries (PVRa), but downstream venous resistance (PVRv) may also contribute to pulmonary hypertension (PH) associated with left heart diseases (PH-LHD). In patients referred for right heart catheterization, we investigated PVR distribution and its pathophysiologic implications in PH-LHD and other forms of PH. Methods: Patients with PH-LHD (n=292), pulmonary veno-occlusive disease (PVOD, n=10), chronic thromboembolic PH (CTEPH, n=36) and controls without PH (Ctrl, n=28) were included. Pulmonary capillary pressure (Pc) was calculated using the pulmonary artery occlusion technique. PVR was partitioned into PVRa ((mPAP-Pc)/CO) and PVRv ((Pc-PAWP)/CO) with each expressed as % of PVR. PH-LHD was divided into isolated post-capillary PH (IpcPH) and combined post- and pre-capillary PH (CpcPH). Further, PH-LHD was categorized as heart failure with preserved (HFpEF, EF≥50%) or reduced (HFrEF, EF<50%) ejection fraction or left valvular heart disease (L-VHD). In subsets, functional tests (n=71-81) and histological pulmonary venous (PV) remodeling (autopsy, n=15) were performed to investigate correlations with PVR distribution. Results: PVR distribution showed an arterial predominance in Ctrl and CTEPH, and increasing venous contribution in PH-LHD (both IpcPH and CpcPH) and PVOD (Figure A-F). In PH-LHD, patients with HFpEF had proportionately greater venous contribution to PVR than HFrEF and L-VHD (Figure G-I), though not to the extent observed in PVOD. In subsets, PVRv was more strongly correlated with E/e’, extravascular lung water estimated by sonographic B-lines, arterial PO 2 , pulmonary dead space fraction (VD/VT), DLCO, and, among the autopsy series, PV intimal thickness as compared to PVRa (Figure J-O). Conclusions: Pulmonary venous contributions to PVR are amplified in patients with PH-LHD, which is correlated with greater lung congestion, ventilatory and gas exchange abnormalities, and histological venous remodeling. Further study is required to determine the molecular mechanism and novel therapeutics of pulmonary venous disease in PH-LHD.

BACKGROUND Cellular senescence, an irreversible cell cycle arrest with secretory phenotype, is a hallmark of skin aging. Regenerative exosome-based approaches, such as topical human platelet extract (HPE), are emerging to target age-related skin dysfunction. OBJECTIVE To evaluate the cellular and molecular effects of topical HPE for skin rejuvenation after 12 weeks of twice daily use. METHODS Skin biopsies were obtained for histological evaluation of senescence markers, p16INK4a and p21CIP1/WAF1. Telomere-associated foci, coassociation of telomeres, and DNA damage marker, γH2AX, were assessed. RNA sequencing evaluated senescence associated secretory phenotype (SASP) and extracellular matrix pathways. RESULTS p16INK4a and p21CIP1/WAF1 staining in senescent skin cells revealed low and high expression subgroups that did not correspond to chronological age. Topical HPE significantly reduced high p16INK4a cells in the dermis (p = .02). There was also a decrease in telomere damage after topical HPE (p = .03). In patients with high senescent cells at baseline, there was a 40% reduction in proinflammatory SASP. Extracellular matrix remodeling pathways, including collagen and elastic fibers, were up-regulated. CONCLUSION Topical HPE, applied on intact skin, reduced senescence signaling and senescence-associated telomere damage after 12 weeks of twice daily use, targeting a path for skin longevity or healthy skin aging.

Introduction: Cardiac differentiation protocols enable derivation of cardiomyocytes (CM). from human induced pluripotent stem cell (iPS). However, limited tools are available to ensure enhanced iPS-CM maturation without the need for prolonged and complex culture. Research Question: This study assessed whether the mesodermal and cardiopoiesis inductor, Brachyury (T), complements standard cardiac differentiation and augments structural and functional maturation of iPS-CM. Aims: The impact of T mRNA introduction prior to initiation of cardiac differentiation was characterized on: i) cardiac transcription factor expression; ii) structural and functional hallmarks of maturity; and iii) cardiotoxicity. Methods: RT-qPCR was employed to monitor the expression of cardiac-specific transcription factors. Transmission electron microscopy enabled the assessment of cellular ultrastructure. Seahorse measurements were used to determine basal respiration. Fluo4 staining was used to measure calcium transients with external field stimulation. Cardiotoxicity was measured as the impact of doxorubicin on calcium handling and cell survival. Results: Transfection with T prompted early and sustained upregulation of the cardiac transcription factors Nkx2.5 (10-fold; FDR<0.001) and MEF2C (7.2-fold; FDR<0.001). Mitochondrial area was increased with T transfection (P<0.001) and T-transfected iPS-CM exhibited greater basal respiration (FDR<0.05), greater calcium handling resilience in response to field stimulation, and a more mature transient morphology. Following doxorubicin exposure T transfected iPS-CM exhibited a greater compromise in calcium handling (FDR<0.001), and exaggerated cell death. Conclusion: Induction of human iPS with T prior to initiation of cardiac differentiation enhanced signatures of structural and functional maturity, and provided more robust readouts of drug toxicity.

Abstract Cardiopoiesis-primed human stem cells exert sustained benefit in treating heart failure despite limited retention following myocardial delivery. To assess potential paracrine contribution, the secretome of cardiopoiesis conditioned versus naïve human mesenchymal stromal cells was decoded by directed proteomics augmented with machine learning and systems interrogation. Cardiopoiesis doubled cellular protein output generating a distinct secretome that segregated the conditioned state. Altering the expression of 1035 secreted proteins, cardiopoiesis reshaped the secretome across functional classes. The resolved differential cardiopoietic secretome was enriched in mesoderm development and cardiac progenitor signaling processes, yielding a cardiovasculogenic profile bolstered by upregulated cardiogenic proteins. In tandem, cardiopoiesis enhanced the secretion of immunomodulatory proteins associated with cytokine signaling, leukocyte migration, and chemotaxis. Network analysis integrated the differential secretome within an interactome of 1745 molecules featuring prioritized regenerative processes. Secretome contribution to the repair signature of cardiopoietic cell-treated infarcted hearts was assessed in a murine coronary ligation model. Intramyocardial delivery of cardiopoietic cells improved the performance of failing hearts, with undirected proteomics revealing 50 myocardial proteins responsive to cell therapy. Pathway analysis linked the secretome to cardiac proteome remodeling, pinpointing 17 cardiopoiesis-upregulated secretome proteins directly upstream of 44% of the cell therapy-responsive cardiac proteome. Knockout, in silico, of this 22-protein secretome-dependent myocardial ensemble eliminated indices of the repair signature. Accordingly, in vivo, cell therapy rendered the secretome-dependent myocardial proteome of an infarcted heart indiscernible from healthy counterparts. Thus, the secretagogue effect of cardiopoiesis transforms the human stem cell secretome, endows regenerative competency, and upregulates candidate paracrine effectors of cell therapy-mediated molecular restitution.

Summary: Exosomes, or extracellular vesicles, represent the latest cell-free addition to the regenerative medicine toolkit. In vitro preclinical studies have demonstrated the safety and efficacy of exosomes, which vary based on source and biomanufacturing, for a myriad of potential therapeutic applications relevant to skin and soft tissue reconstruction. Primary search was performed in September 2021 on the MEDLINE database via PubMed and Ovid, with focus on articles about therapeutic application of exosomes or extracellular vesicles. In total, 130 articles met criteria for applicability, including early-stage clinical trials, preclinical research studies with in vivo application, and articles applicable to plastic and reconstructive surgery and dermatology. Most studies used animal models of human disease processes, using either animal donor cells to isolate exosomes, or human donor cells in animal models. Exosome technology has catapulted as an acellular therapeutic vehicle with off-the-shelf accessibility. These features eliminate prior threshold for broad adoption of regenerative cell-based therapies into surgical and medical practice. To date, there are no exosome products approved by the US Food and Drug Administration. This review highlights exosomes as the new frontier in regenerative medicine and outlines its preclinical therapeutic applications for cutaneous repair and restoration.

Axillary artery intra-aortic balloon pump (axIABP) placement has been implemented as a bridging solution before heart transplantation. This study evaluates complications associated with axIABP support and describes an approach to minimize adverse events. We previously described a percutaneous approach for axIABP placement. However, patients receiving axIABP between September 1, 2017, and September 26, 2019 (n = 32) demonstrated a high rate of balloon pump malfunction (8/32; 25%) and other complications (totaling 15/32; 47%). Sixty-four patients were sequentially treated under a revised protocol. Compared to the initial cohort, no significant differences in demographics were noted. A significant reduction in rate of balloon malfunction (8/32, 25% vs. 1/64, 2%; p < 0.001) and total complications (15/32, 47% vs. 10/64, 16%; p = 0.0025) during the period of support were noted after intervention. Subsequent analysis of total complications per device size (40 vs. ≤ 34 ml balloon) revealed significantly reduced complications in patients with smaller devices (40% vs. 13%, respectively; p = 0.0022). This study provides guidelines to limit complications in patients supported with axIABP, facilitating a protracted period of bridging support.

Background The purpose of this study was to investigate a therapeutic approach targeting the inflammatory response and consequent remodeling from ischemic myocardial injury. Methods and Results Coronary thrombus aspirates were collected from patients at the time of ST‐segment–elevation myocardial infarction and subjected to array‐based proteome analysis. Clinically indistinguishable at myocardial infarction (MI), patients were stratified into vulnerable and resilient on the basis of 1‐year left ventricular ejection fraction and death. Network analysis from coronary aspirates revealed prioritization of tumor necrosis factor‐α signaling in patients with worse clinical outcomes. Infliximab, a tumor necrosis factor‐α inhibitor, was infused intravenously at reperfusion in a porcine MI model to assess whether infliximab‐mediated immune modulation impacts post‐MI injury. At 3 days after MI (n=7), infliximab infusion increased proregenerative M2 macrophages in the myocardial border zone as quantified by immunofluorescence (24.1%±23.3% in infliximab versus 9.29%±8.7% in sham; P <0.01). Concomitantly, immunoassays of coronary sinus samples quantified lower troponin I levels (41.72±7.34 pg/mL versus 58.11±10.75 pg/mL; P <0.05) and secreted protein analysis revealed upregulation of injury‐modifying interleukin‐2, ‐4, ‐10, ‐12, and ‐18 cytokines in the infliximab‐treated cohort. At 4 weeks (n=12), infliximab treatment resulted in significant protective influence, improving left ventricular ejection fraction (53.9%±5.4% versus 36.2%±5.3%; P <0.001) and reducing scar size (8.31%±10.9% versus 17.41%±12.5%; P <0.05). Conclusions Profiling of coronary thrombus aspirates in patients with ST‐segment–elevation MI revealed highest association for tumor necrosis factor‐α in injury risk. Infliximab‐mediated immune modulation offers an actionable pathway to alter MI‐induced inflammatory response, preserving contractility and limiting adverse structural remodeling.

Introduction: The process of engaging stem cells towards a cardiopoietic (CP) state was established using a protein-based cocktail consisting of multiple growth factors. Although this regenerative enhancement protocol has been successfully tested in advanced clinical trials, it remains resource-intensive. Recent efforts have focused on streamlining cardiopoiesis through a protein-independent alternative that leverages a transfection-based mRNA approach. Microencapsulated modified messenger RNA (M3RNA) was utilized to deliver brachyury (T), an early mesodermal transcription factor to provoke early lineage specification in pluripotent cells. Hypothesis: Transfection of a human pluripotent stem cell source with T induces early expression of CP transcription factors to accelerate cardiac differentiation. Methods: Human pluripotent stem cells were transfected with T and maintained for 14 days. Expression of the cardiopoietic markers MEF2C, GATA4, and Nkx2.5 was analyzed using RT-qPCR, in tandem with MYH6 at days 10 and 20. Differentiation proficiency was independently corroborated by assessing Mef2c and Nkx2.5 expression by IF. Results: Following transfection with T, Nkx2.5, MEF2C and GATA4 were significantly induced at 72h (60-, 20- and 40-fold, respectively, p<0.01 for all 3 markers vs baseline), reflecting timing of differentiation initiation. At 5 days post differentiation, expression of the cardiac-specific Nkx2.5 increased by 5 fold vs control and the cell cycle regulator CHIR (p<0.01), suggesting successful persistent induction of cardiopoeisis. At 10 and 20 days of differentiation, RNA expression of MYH6 was 10-15 times induced in human pluripotent cells transduced with T (p < 0.0001, and p < 0.001 vs control, respectively), compared to 2 times (p<0.05, p<0.01 vs control, respectively) in CHIR treated cohorts. Accordingly, at 42 days post-induction of differentiation, a greater number of cells expressed MLC2V and cTnT (p<1e-05, <1e-07, respectively vs control), driving a robust beating pattern. Conclusion: This study implements a single gene T M3RNA-based approach to readily induce cardiac differentiation from pluripotent sources, exceeding available commercial platforms.

Introduction: We aim to elucidate the incidence of major complications related to right heart catheterization (RHC) and ascertain if there are unique risks with right ventricular biopsy. Methods: Diagnostic RHC procedures from 1/1/2002 through 12/31/2013 were identified using the clinical scheduling system at Mayo Clinic, Rochester. Major complications were identified through electronic records using International Classification of Diseases, Ninth Revision billing codes. All events were recorded and adjudicated. Analysis was performed on four separate patient categories (RHC/RV angiography alone, RV biopsy alone, multiple RHC procedures, and concurrent RHC/LHC procedures) and the overall group. Primary outcomes are described in Table 1. Outcomes were measured within 7 days of the procedure, except for death (same day events) and tricuspid regurgitation (variable time endpoints). Results: There were 17,696 RHC procedures (5,556 RHC/RV angiography, 3,846 RV biopsy alone, 776 multiple RHC procedures, and 7,518 combined RHC/LHC). Patient population had a mean age of 56.5 years (15.3) and was predominantly male (58.5%). Same-day death related to RHC procedure occurred in 1 procedure or 0.6 of 10,000 RHCs. There was no significant difference in the risk of complications across RHC procedure categories except for worsening tricuspid regurgitation, which was significantly (p<0.001) more prevalent with RV biopsy (392 cases, 6.0%) than without (136 cases, 1.2%). Conclusion: The incidence of major complications related to right heart catheterization is rare. Worsening tricuspid regurgitation is the most frequently identified change with a significantly higher prevalence with biopsies.