John Cochran VA Medical Center

Sodium-glucose co-transporter 2 inhibitors are widely used to treat patients with type 2 diabetes and exhibit beneficial cardiovascular effects beyond glucose lowering. In this study, we investigated their potential to alleviate vaso-occlusive events and organ damage in sickle cell disease (SCD) mice. Intravital and immunofluorescence microscopy reveal that a 4-day oral administration of dapagliflozin (DAPA) or sotagliflozin (SOTA) significantly reduces neutrophil adhesion and transmigration in cremaster venules, with SOTA showing greater inhibition, and down-regulates E-selectin and intercellular adhesion molecule-1 (ICAM-1) expression in cremaster venules of TNF-α-challenged SCD mice. Intriguingly, only SOTA improves mouse survival acutely. Similar inhibitory effects on neutrophil recruitment are observed in SCD mice subjected to hypoxia-reoxygenation. Flow chamber assays indicate that neither drug directly affects neutrophil or endothelial cell adhesive function. In addition, treatment of neutrophils and platelets from SCD mice and patients with DAPA or SOTA does not affect their activation. When administered for 4 months, DAPA or SOTA mitigates neutrophil recruitment and enhances microcirculation in cremaster venules of TNF-α-challenged SCD mice, while only SOTA confers a survival benefit. Both drugs reduce leucocyte infiltration in the liver or lungs, suggesting their ability to protect against organ damage. Co-administration with hydroxyurea for 4 months does not enhance these effects. Multiplex analysis shows that DAPA and SOTA lower plasma levels of soluble P-selectin, ICAM-1, S100A8/A9, and pro-inflammatory cytokines in SCD mice. Our findings suggest that DAPA and SOTA mitigate vaso-occlusive events in SCD, with SOTA providing superior benefits.

Translating human genomic discoveries into mechanistic insights requires linking genetic variations to candidate genes and their causal functional phenotypes. Genome-wide association studies have consistently identified LIPA (lipase A, lysosomal acid type) as a risk locus for coronary artery disease, with previous analyses prioritising LIPA as a likely causal gene. However, functional studies elucidating causal variants, regulatory mechanisms, target cell types, and their causal impact on atherosclerosis have been lacking. This study aims to address this gap by establishing the variant-to-function relationship at the LIPA locus. Post-genome-wide association study pipelines and molecular biology techniques, including expression quantitative trait loci analysis, Tri-HiC, luciferase assay, CRISPRi, allele-specific binding, motif analysis, and electrophoretic mobility shift assay, were used to link functional variants to target genes and define the direction of their regulatory effects in causal cell types. To determine how increased myeloid LIPA impacts atherosclerosis, myeloid-specific Lipa overexpression mice on an Ldlr-/- background were generated. Coronary artery disease-risk alleles in the LIPA locus increase LIPA expression and enzyme activity specifically in monocytes/macrophages by enhancing PU.1 binding to an intronic enhancer region that interacts with the LIPA promoter. Myeloid-specific Lipa overexpression in Ldlr-/- mice fed a western diet resulted in larger atherosclerotic lesions, accompanied by altered macrophage function, characterized by increased accumulation of lesional macrophages derived from circulating monocytes, reduced neutral lipid content, and up-regulation of integrin and extracellular matrix pathway genes. The work establishes a direct causal link between LIPA-risk alleles and increased monocyte/macrophage LIPA that exacerbates atherosclerosis, bridging human functional genomic evidence to the mechanistic understanding of coronary artery disease.

ABSTRACT Macroautophagy/autophagy is markedly inhibited in the hearts of elderly obese patients with heart failure and preserved ejection fraction (HFpEF). However, the therapeutic relevance and underlying signaling mechanisms of the decline of autophagy in HFpEF remain unclear. We observed that therapeutic nicotinamide adenine dinucleotide (NAD+) repletion via nicotinamide supplementation restores cardioprotective autophagy and mitophagy in preclinical models of obesity-related HFpEF. Targeted and untargeted cardiac acetylome profiling revealed no significant deacetylation of essential autophagy-related proteins, including ATG5, ATG7 and mammalian Atg8-family members (ATG8s), suggesting a SIRT (sirtuin)-independent mechanism of autophagy induction by nicotinamide. Instead, cardiac transcriptomic analysis revealed major shifts in insulin-IGF1 (insulin-like growth factor 1) signaling, a known autophagy inhibitory pathway. Nicotinamide supplementation reverses the HFpEF-associated increase in insulin-IGF1 signaling, whereas exogenous IGF1 counteracts nicotinamide-induced autophagy. Importantly, nicotinamide fails to exert cardioprotective effects in mice lacking the autophagy-related protein ATG5 in cardiomyocytes, implicating autophagy as essential for the therapeutic response. In patients with HFpEF, a metabolic shift diverting nicotinamide away from NAD+ biosynthesis toward catabolism strongly correlates with worsening heart failure and increased cardiovascular mortality, even after adjusting for traditional risk factors. In sum, we demonstrate that NAD+ replenishment improves cardiometabolic HFpEF by restoring cardiac autophagy through suppression of excessive IGF1 signaling.

Age-related macular degeneration (AMD) is a leading cause of blindness in people over 50. AMD and cardiovascular disease share risk factors including age, impaired lipid metabolism, and extracellular lipid deposition. Because of its importance in age-related diseases, we hypothesize that apolipoprotein M (ApoM), a lipocalin that binds sphingosine-1-phosphate (S1P), might restore lipid homeostasis and retinal function in AMD. In support, we find that human patients with AMD demonstrate significantly reduced ApoM compared to controls. In mice with impaired retinal cholesterol efflux, ApoM improves retinal pigment epithelium (RPE) function and lipotoxicity in an S1P- and S1P receptor 3-dependent manner. Ultrastructural evidence of enhanced melanosome-lipid droplet interactions led us to hypothesize and demonstrate that ApoM-S1P signaling drives RPE-specific lysosomal lipid catabolism. RPE-specific knockout of lysosomal acid lipase recapitulates features of AMD. Our study defines a novel role for ApoM/S1P signaling in AMD driven by RPE lipotoxicity, mediated by cell-autonomous lysosomal lipid catabolism.

BackgroundSodium-glucose cotransporter inhibitors (SGLT2is) reduce inflammation and maintain vascular integrity. Apolipoprotein M (ApoM) is crucial for vascular integrity via sphingosine-1-phosphate (S1P) signaling and is inversely linked with mortality in sepsis and COVID-19.ObjectivesThe authors tested if SGLT2i (dapagliflozin [Dapa]) increases ApoM in mice using lipopolysaccharide (LPS) and in humans with COVID-19.MethodsDiet-induced obese mice (n = 14-15/group), proximal tubule-specific knockout of the multiligand protein receptor Lrp2 (Lrp2KO) mice (n = 5-8/group), Ly6G-Cre LoxP-STOP-TdTomato mice (n = 3-5/group), ApomKO mice (n = 3-5/group), and ApomTG mice (n = 3-5/group) were randomized to receive either vehicle or Dapa (1.25 mg/kg daily) for 4 days before LPS (10 mg/kg IP). Outcomes included ApoM protein levels (Western and enzyme-linked immunosorbent assay) and intravital microscopy to assess endothelial leak and neutrophil behavior. Plasma samples from ACTIV-4a participants (standard of care, n = 37; standard of care + SGLT2i, n = 15) were analyzed for circulating ApoM by enzyme-linked immunosorbent assay. Statistical analyses included two-way analysis of variance for mice and t-test or Mann-Whitney test for humans.ResultsDapa restored circulating ApoM levels in LPS-treated mice (0.017 vs 0.035 [a.u./μL], P = 0.0489) and increased ApoM levels in patients randomized to SGLT2i (0.5240 vs 0.6537 [μM], P = 0.0101). LRP2 knockout blocked Dapa's effect on ApoM. In vitro, Dapa stimulated Lrp2-dependent uptake of ApoM-GFP. Dapa attenuated vascular leak induced by LPS in an ApoM-dependent manner.ConclusionsSGLT2i maintains Lrp2 levels, preserving ApoM and promoting endothelial barrier integrity in acute inflammation, indicating a novel protective mechanism of SGLT2i through ApoM preservation.

Iron deficiency (ID) is currently defined as a serum ferritin level <100 or 100 to 299 ng/mL with transferrin saturation (TSAT) <20%. Serum ferritin and TSAT are currently used to define absolute and functional ID. However, individual markers of iron metabolism may be more informative than current arbitrary definitions of ID. We assessed prognostic associations of ferritin, serum iron, and TSAT among 2050 participants with heart failure (HF) with reduced/mid-range (n=1821) or preserved (n=229) left ventricular ejection fraction enrolled in the PHFS (Penn HF Study), a prospective cohort study. We measured 4928 plasma proteins using an aptamer-based assay (SOMAScanv4) and assessed prognostic and proteomic associations of markers of iron metabolism. Ferritin concentrations were not associated with outcomes, whereas low TSAT and serum iron were associated with the risk of all-cause death (TSAT: standardized hazard ratio, 0.84 [95% CI, 0.76-0.93]; P=0.001; serum iron: standardized hazard ratio, 0.87 [95% CI, 0.79-0.96]; P=0.007). Similarly, TSAT was associated with the risk of death or HF-related admission (standardized hazard ratio, 0.89 [95% CI, 0.83-0.95]; P=0.0006). Significant interactions between TSAT and HF with preserved ejection fraction status were found such that TSAT was more strongly associated with the risk of death and death or HF-related admission in HF with preserved ejection fraction. We identified 359 proteins associated with TSAT, including TFRC (transferrin receptor protein; β, -0.455; P<0.0001) and CRP (C-reactive protein; β, -0.355; P<0.0001). Pathway analyses demonstrated associations with lipid metabolism, complement activation, and inflammation. In contrast to the robust associations between TSAT and outcomes, ID and absolute ID defined by current criteria were not associated with death or death or HF-related admission. TSAT was associated with outcomes regardless of the presence of functional versus absolute ID. Low TSAT, but not ferritin concentrations, is significantly associated with adverse outcomes in HF. Low TSAT is more strongly associated with outcomes in HF with preserved ejection fraction. Pathways related to inflammation and lipid metabolism are associated with low TSAT in HF.

Nanomedicine holds great potential for revolutionizing medical treatment. Ongoing research and advancements in nanotechnology are continuously expanding the possibilities, promising significant advancements in healthcare. To fully harness the potential of nanotechnology in medical applications, it is crucial to conduct safety evaluations for the nanomedicines that offer effective benefits in the preclinical stage. Our recent efficacy studies indicated that rapamycin perfluorocarbon (PFC) nanoparticles showed promise in mitigating cisplatin-induced acute kidney injury (AKI). As cisplatin is routinely administered to ovarian cancer patients as their first-line chemotherapy, in this study, we focused on evaluating the safety of rapamycin PFC nanoparticles in mice bearing ovarian tumor xenografts. Specifically, this study evaluated the effects of repeat-dose rapamycin PFC nanoparticle treatment on vital organs, the immune system, and tumor growth and assessed pharmacokinetics and biodistribution. Our results indicated that rapamycin PFC nanoparticle treatment did not cause any detectable adverse effects on cardiac, renal, or hepatic functions or on splenocyte populations, but it reduced the splenocyte secretion of IL-10, TNFα, and IL12p70 upon IgM stimulation. The pharmacokinetics and biodistribution results revealed a significant enhancement in the delivery of rapamycin to tumors by rapamycin PFC nanoparticles, which, in turn, led to a significant reduction in ovarian tumor growth. Therefore, rapamycin PFC nanoparticles have the potential to be clinically beneficial in cisplatin-treated ovarian cancer patients.

Growth differentiation factor-15 (GDF-15) is an emerging biomarker in several conditions. This SLR, conducted following PRISMA guidelines, examined the association between GDF-15 concentration and range of adverse outcomes in patients with heart failure (HF). Publications were identified from Embase® and Medline® bibliographic databases between January 1, 2014, and August 23, 2022 (congress abstracts: January 1, 2020, to August 23, 2022). Sixty-three publications met the eligibility criteria (55 manuscripts and 8 abstracts; 45 observational studies and 18 post hoc analyses of randomized controlled trials [RCTs]). Of the 19 outcomes identified, the most frequently reported longitudinal outcomes were mortality (n = 32 studies; all-cause [n = 27] or cardiovascular-related [n = 6]), composite outcomes (n = 28; most commonly mortality ± hospitalization/rehospitalization [n = 19]), and hospitalization/re-hospitalization (n = 11). The most common cross-sectional outcome was renal function (n = 22). Among longitudinal studies assessing independent relationships with outcomes using multivariate analyses (MVA), a significant increase in risk associated with higher baseline GDF-15 concentration was found in 22/24 (92 %) studies assessing all-cause mortality, 4/5 (80 %) assessing cardiovascular-related mortality, 13/19 (68 %) assessing composite outcomes, and 4/8 (50 %) assessing hospitalization/rehospitalization. All (7/7; 100 %) of the cross-sectional studies assessing the relationship with renal function by MVA, and 3/4 (75 %) assessing exercise capacity, found poorer outcomes associated with higher baseline GDF-15 concentrations. This SLR suggests GDF-15 is an independent predictor of mortality and other adverse but nonfatal outcomes in patients with HF. A better understanding of the prognostic role of GDF-15 in HF could improve clinical risk prediction models and potentially help optimize treatment regimens.