👤 Manish A Parikh

The contribution of glucose-dependent insulinotropic polypeptide receptor (GIPR) signalling in brown adipose tissue (BAT) remains underexplored. We studied the acute effects of exogenous acyl-GIP (1 nmol/kg) administration on whole-body lipid handling and fatty acid oxidation, using lipid tolerance tests (LTT) and indirect calorimetry, respectively. We demonstrate that in obese male mice, acute acyl-GIP administration improves lipid tolerance; however, pharmacological inhibition of GIPR, or genetic removal of GIPR globally or with the Myf5-Cre driver, completely abolishes GIP-mediated improvements in lipid tolerance, implicating GIPR in BAT. GIP-mediated improvements in lipid tolerance are associated with an increase in BAT lipid uptake, linked to increases in BAT lipoprotein lipase activity. Our data also reveal that BAT GIPR signalling is necessary for GIP-mediated increases in whole-body fatty acid oxidation, as Myf5-Cre: Gipr mice do not shift substrate oxidation upon GIP administration. Our findings suggest that BAT should be more closely considered in studies examining GIP's effects on whole-body metabolism in rodent models. Show less

Despite widespread use of high-intensity statins, ezetimibe, and proprotein convertase subtilisin/kexin type 9 inhibitors, substantial atherosclerotic cardiovascular disease risk persists, especially in people with heterozygous familial hypercholesterolemia or elevated lipoprotein(a) [Lp(a)] levels. Cholesteryl ester transfer protein (CETP) inhibitors block the transfer of hydrophobic cholesteryl esters from high-density lipoprotein to apolipoprotein B (apoB)-containing particles. This process raises high-density lipoprotein-C and lowers low-density lipoprotein-C, apoB, and Lp(a) levels. The first-generation of CETP inhibitors was limited by toxicity, neutral outcomes, or unfavorable pharmacokinetics. Obicetrapib is a next-generation amphipathic CETP inhibitor that selectively targets both CETP's hydrophobic and hydrophilic tunnels. It reduces low-density lipoprotein-C by about 30-51%, apoB by 20-33%, and Lp(a) by 30-57% without causing tissue accumulation or toxicity. Phase 3 trials (BROOKLYN, BROADWAY, TANDEM) show that obicetrapib is effective when added to maximized therapy, with a safety profile similar to placebo. Its consistent reduction of Lp(a) addresses an important unmet need. In addition to lowering atherogenic lipoproteins, early data suggest potential for neuroprotection, such as reductions in p-tau217 seen among APOE4 carriers. A 2025 pooled analysis offers initial evidence that major adverse cardiovascular events are reduced, as studied in the ongoing PREVAIL outcomes trial. This review covers CETP biology and tunnel mechanics, outcomes from earlier CETP inhibitor studies, obicetrapib's pharmacology, and current efficacy and safety data, and will clarify its potential place in lipid management today. Show less

Clustered regularly interspaced short palindromic repeats (CRISPR)-based genome editing has expanded from experimental biology to early clinical application, raising the possibility of durable therapies for cardiovascular disease. Because many cardiac conditions are monogenic, they provide clear targets for allele-specific correction or modulation. In hypertrophic cardiomyopathy, preclinical research has shown that base editing of pathogenic MYH7 and MYBPC3 mutations can restore sarcomere function; concurrently, RNA-targeting approaches selectively suppress mutant transcripts. Dilated cardiomyopathy is more heterogeneous: TTN truncations cause haploinsufficiency that can be offset by CRISPR activation, while RBM20 and LMNA mutations require precise correction or interference to restore splicing and nuclear stability. Genome editing is also being tested in familial hypercholesterolemia, where inactivation of PCSK9 using lipid nanoparticle-delivered base editors has now advanced to first-in-human trials, achieving sustained LDL-C lowering. Concurrently, efforts targeting ANGPTL3 and APOB highlight the prospect of multigene modulation of lipid metabolism. In arrhythmic syndromes, patient-derived cardiomyocytes edited at SCN5A and KCNQ1 genes have enabled high-fidelity disease models, while in vivo correction of RYR2 in catecholaminergic polymorphic ventricular tachycardia confirms the viability of editing an arrhythmia substrate. In cardiac regeneration, CRISPR activation of developmental transcription factors has enabled direct reprogramming of fibroblasts into cardiomyocyte-like cells within scar tissue. Even with these advances, delivery remains a bottleneck due to immune responses to viral vectors, limitations in the efficiency of lipid nanoparticles in the heart, and the precision required to target cardiomyocytes or conduction cells, all of which slow progress. Future work will depend as much on technical refinement as on navigating ethical, regulatory, and societal concerns. Show less

Cholesterol efflux capacity (CEC) of HDL (high-density lipoprotein) is inversely associated with incident cardiovascular events, independent of HDL cholesterol. Obesity is characterized by low HDL cholesterol and impaired HDL function, such as CEC. Bariatric surgery, including Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), broadly leads to improved cardiovascular outcomes, but impacts on risk factors differ by procedure, with greater improvements in weight loss, blood pressure, and glycemic control after RYGB, but greater improvements in HDL cholesterol and CEC levels after SG. This study sought to determine effects of RYGB and SG on HDL protein and lipid cargo and investigate associations with CEC changes. We prospectively studied nondiabetic, premenopausal Hispanic women with severe obesity not using lipid medications undergoing RYGB (n=31) or SG (n=36). Anthropometric measurements and blood sampling were obtained before and at 6 and 12 months after surgery. HDL was isolated from plasma, and quantitative proteomic and lipidomic assessments were performed with LC-MS/MS (liquid chromatography with tandem mass spectrometry). CEC was assessed ex vivo using apoB-depleted serum. Participants experienced similar, significant weight loss over 12 months following bariatric surgery (38.0±10.4 kg) regardless of the procedure. Relative quantities of 47 proteins (34 increased, 13 decreased) and 150 lipids (71 increased, 79 decreased) carried on HDL were significantly altered following either surgical procedure. Proteins with similar aggregate response patterns were clustered into 15 groups (5 increased, 5 decreased, 5 minimal change) and lipids with similar aggregate responses into 25 groups (7 increased, 11 decreased, 7 minimal change). Network mediation analyses suggested that changes in 4 protein and 2 lipid clusters mediated changes in ABCA1 (ATP-binding cassette transporter A1) CEC and that 1 lipid cluster mediated changes in non-ABCA1 CEC. The protein and lipid clusters that mediated changes in CEC were distinct between SG and RYGB. Bariatric surgery produces substantial changes in HDL lipid and protein cargo, and specific changes may mediate changes in HDL function in CEC. Further study of these mechanisms may lead to improved interventions to reduce cardiovascular risk in patients with obesity. Show less

Hypertriglyceridemia has been proposed as a risk factor for atherosclerotic cardiovascular disease (ASCVD). Triglycerides (TG) are viewed as a marker for remnant cholesterol in triglyceride-rich lipoproteins, as this remnant cholesterol has been identified as a causal risk factor for ASCVD. The limited number of effective treatments for elevated TG has fueled the search for novel pharmacotherapy options, and multiple medication classes are being explored. Apolipoprotein C3 (APOC3) and angiopoietin-like protein 3 (ANGPTL3) are among the most promising targets. Several novel agents utilizing these pathways, including olezarsen, plozasiran, and zodasiran, are currently under development for the management of elevated TG, with olezarsen approved in 2024 for the management of familial chylomicronemia syndrome. This comprehensive review provides updated insights into the development of novel hypertriglyceridemia treatments. Show less

Prenatal tobacco smoke exposure (TSE) has been associated with significant alterations in DNA methylation (DNAm), an epigenetic mechanism with potential functional consequences to child development. This pilot study aimed to investigate differential DNAm patterns in preterm children with and without prenatal TSE using reduced representation bisulfite sequencing (RRBS) to interrogate a wider array of sites than in more common approaches, namely microarrays. Buccal swabs were collected from 16 two-year-old children (7 with TSE, 9 without), and DNAm was quantified at over 1.3 million CpG sites. To identify differential DNAm, univariable analyses were first performed and followed by Bayesian beta-binomial hierarchical regression models for sequence count data including adjustment for potential confounders. False Discovery Rate correction was used to account for multiple comparisons. Significant differential methylation was observed at CpG sites within intronic regions of the Show less

An estimated 1 in 500 people live with hypertrophic cardiomyopathy (HCM), a disease for which genetic diagnosis can identify family members at risk, and increasingly guide therapy. Mutations in the myosin binding protein C3 ( We developed a scaled multidimensional mapping strategy to evaluate the functional impact of variants across a critical domain of MYBPC3. We incorporate saturation base editing at the native Our multidimensional mapping strategy enabled high-resolution functional analysis of This work provides a platform for extending genome engineering in iPSCs to multiplexed assays of variant effects across diverse disease-relevant cellular phenotypes, enhancing the understanding of variant pathogenicity and uncovering novel biological mechanisms that could inform therapeutic strategies. Show less

Females with hypertrophic cardiomyopathy present at a more advanced stage of the disease and have a higher risk of heart failure and death. The factors behind these differences are unclear. We aimed to investigate sex-related differences in clinical and genetic factors affecting adverse outcomes in the Sarcomeric Human Cardiomyopathy Registry. Cox proportional hazard models were fit with a sex interaction term to determine if significant sex differences existed in the association between risk factors and outcomes. Models were fit separately for females and males to find the sex-specific hazard ratio (HR). After a mean follow-up of 6.4 years, females had a higher risk of heart failure (HR, 1.51 [95% CI, 1.21-1.88]; We found that clinical and genetic factors contributing to adverse outcomes in hypertrophic cardiomyopathy affect females and males differently. Thus, research to inform sex-specific management of hypertrophic cardiomyopathy could improve outcomes for both sexes. Show less

Classically, hypertrophic cardiomyopathy (HCM) has been viewed as a single-gene (monogenic) disease caused by pathogenic variants in sarcomere genes. Pathogenic sarcomere variants are individually rare and convey high risk for developing HCM (highly penetrant). Recently, important polygenic contributions have also been characterized. Low penetrance sarcomere variants (LowSVs) at intermediate frequencies and effect sizes have not been systematically investigated. We hypothesize that LowSVs may be common in HCM with substantial influence on disease risk and severity. Among all sarcomere variants observed in the Sarcomeric Human Cardiomyopathy Registry (SHaRe), we identified putative LowSVs defined by (1) population frequency greater than expected for highly penetrant (monogenic) HCM (allele frequency >5×10 Among 6045 patients and 1159 unique variants in sarcomere genes, 12 LowSVs were identified. LowSVs were collectively common in the general population (1:350) and moderately enriched in HCM (aggregate odds ratio, 14.9 [95% CI, 12.5-17.9]). Isolated LowSVs were associated with an older age of HCM diagnosis and fewer adverse events. However, LowSVs in combination with a pathogenic sarcomere variant conferred higher morbidity (eg, composite adverse event hazard ratio, 5.4 [95% CI, 3.0-9.8] versus single pathogenic sarcomere variant, 2.0 [95% CI, 1.8-2.2]; This study establishes a new class of low penetrance sarcomere variants that are relatively common in the population. When penetrant, isolated LowSVs cause mild HCM. In combination with pathogenic sarcomere variants, LowSVs markedly increase disease severity, supporting a clinically significant additive effect. Last, LowSVs also contribute to age-related remodeling even in the absence of overt HCM. Show less

p38 mitogen-activated protein kinases (MAPKs) participate in autophagic signaling; and previous reports suggest that pyridinyl imidazole p38 MAPK inhibitors, including SB203580 and SB202190, induce cell death in some cancer cell-types through unrestrained autophagy. Subsequent studies, however, have suggested that the associated cytoplasmic vacuolation resulted from off-target inhibition of an unidentified enzyme. Herein, we report that SB203580-induced vacuolation is rapid, reversible, and relies on the class III phosphatidylinositol 3-kinase (PIK3C3) complex and the production of phosphatidylinositol 3-phosphate [PI(3)P] but not on autophagy per se. Rather, vacuolation resulted from the accumulation of Rab7 on late endosome and lysosome (LEL) membranes, combined with an osmotic imbalance that triggered severe swelling in these organelles. Inhibition of PIKfyve, the lipid kinase that converts PI(3)P to PI(3,5)P2 on LEL membranes, produced a similar phenotype in cells; therefore, we performed in vitro kinase assays and discovered that both SB203580 and SB202190 directly inhibited recombinant PIKfyve. Cancer cells treated with either drug likewise displayed significant reductions in the endogenous levels of PI(3,5)P2. Despite these results, SB203580-induced vacuolation was not entirely due to off-target inhibition of PIKfyve, as a drug-resistant p38α mutant suppressed vacuolation; and combined genetic deletion of both p38α and p38β dramatically sensitized cells to established PIKfyve inhibitors, including YM201636 and apilimod. The rate of vacuole dissolution (i.e., LEL fission), following the removal of apilimod, was also significantly reduced in cells treated with BIRB-796, a structurally unrelated p38 MAPK inhibitor. Thus, our studies indicate that pyridinyl imidazole p38 MAPK inhibitors induce cytoplasmic vacuolation through the combined inhibition of both PIKfyve and p38 MAPKs, and more generally, that p38 MAPKs act epistatically to PIKfyve, most likely to promote LEL fission. Show less

p38 mitogen-activated protein kinases (MAPKs) regulate early endocytic trafficking, but their effects on late endocytic trafficking remain unclear. Herein, we report that the pyridinyl imidazole p38 MAPK inhibitors, SB203580 and SB202190, induce a rapid but reversible Rab7-dependent accumulation of large cytoplasmic vacuoles. While SB203580 did not induce canonical autophagy, phosphatidylinositol 3-phosphate [PI(3)P] accumulated on vacuole membranes, and inhibition of the class III PI3-kinase (PIK3C3/VPS34) suppressed vacuolation. Ultimately, vacuolation resulted from the fusion of ER/Golgi-derived membrane vesicles with late endosomes and lysosomes (LELs), combined with an osmotic imbalance in LELs that led to severe swelling and a decrease in LEL fission. Since PIKfyve inhibitors induce a similar phenotype by preventing the conversion of PI(3)P to PI(3,5)P2, we performed Show less

In the present study, we investigated the association between susceptible genetic variants to age-related macular degeneration (AMD) and response to as-needed intravitreal aflibercept injection (IAI) therapy for exudative AMD including both typical neovascular AMD and polypoidal choroidal vasculopathy (PCV) over 12-months. A total of 234 patients with exudative AMD were initially treated with 3 monthly IAI and thereafter as-needed IAI over 12 months. Seven variants of 6 genes including ARMS2 A69S (rs10490924), CFH (I62V:rs800292 and rs1329428), C2-CFB-SKIV2L(rs429608), C3 (rs2241394), CETP (rs3764261) and ADAMTS-9 (rs6795735) were genotyped for all participants using TaqMan technology. After adjusting for age, gender, baseline BCVA and AMD subtype, A (protective) allele of C2-CFB-SKIV2L rs429608 was associated with visual improvement at 12-month (P = 0.003). Retreatment was associated with T(risk) allele of ARMS2 A69S (P = 2.0 × 10 Show less

Genome-wide single nucleotide polymorphism (SNP) data from 936 bipolar disorder (BD) individuals and 940 psychiatrically healthy comparison individuals of North European descent were analyzed for copy number variation (CNV). Using multiple CNV calling algorithms, and validating using in vitro molecular analyses, we identified CNVs implicating several candidate genes that encode synaptic proteins, such as DLG1, DLG2, DPP6, NRXN1, NRXN2, NRXN3, SHANK2, and EPHA5, as well as the neuronal splicing regulator RBFOX1 (A2BP1), and neuronal cell adhesion molecule CHL1. We have also identified recurrent CNVs on 15q13.3 and 16p11.2-regions previously reported as risk loci for neuropsychiatric disorders. In addition, we performed CNV analysis of individuals from 215 BD trios and identified de novo CNVs involving the NRXN1 and DRD5 genes. Our study provides further evidence of the occasional involvement of genomic mutations in the etiology of BD, however, there is no evidence of an increased burden of CNVs in BD. Further, the identification of CNVs at multiple members of the neurexin gene family in BD individuals, supports the role of synaptic disruption in the etiology of BD. Show less

The nuclear receptor liver X receptor [LXR] is activated by endogenous oxidized derivatives of cholesterol. It constitutes a critical receptor in the regulation of various physiological functions related to the development of metabolic and cardiovascular diseases, such as atherosclerosis and diabetes, as well as various other disorders. Both isoforms of LXR, LXRα [NR1H3] and LXRβ [NR1H2], form heterodimers with the isoforms of the retinoid X receptor [RXR], which then regulate the gene expression by binding to DNA sequences associated with target genes. LXR acts as a cholesterol sensor in response to an increased concentration of cholesterol in cells and induces the transcription of genes that protect cells from cholesterol overload. LXRs play numerous roles in controlling cholesterol homeostasis via their actions on bile acid synthesis and metabolism/excretion, reverse cholesterol transport and cholesterol absorption/excretion in the intestines. Therefore, these receptors show great potential as pharmacological targets for anti-atherosclerotic activities. Recent discoveries have also emphasized the important involvement of LXRs in the pathogenesis of diabetes, Alzheimer's disease, inflammation, adrenal steroid synthesis, skin aging and male fertility. However, LXR activation has also been shown to stimulate lipogenesis via sterol regulatory element binding protein-1c, leading to liver steatosis and hypertriglyceridemia. This review summarizes recent scientific discoveries and the biological actions of LXR with a special focus on the involvement of this type of receptor in important diseases and conditions. Show less

Neuronal ceroid lipofuscinosis is a severe neurodegenerative lysosomal storage disorder. Gamma-aminobutyric acid and glutamate deficiency have been reported with CLN1, CLN3, and CLN6. Isolated biopterin/neopterin without dopamine deficiency has been reported in 1 patient with a CLN2 mutation. This report describes a patient with a CLN2 mutation with symptomatic biopterin and dopamine deficiency. A 4-year-old boy presented with intractable epilepsy and developmental regression starting 1 year previously. His exam showed retinopathy, scanning speech, dysmetria, and ataxic fenestrating gait with stooped posture. Electroencephalogram showed generalized spikes with occipital spikes on slow photic stimulation. Brain magnetic resonance images 1 year apart showed significant diffuse atrophy. CLN2 gene sequencing showed pathogenic compound heterozygous mutations. Cerebrospinal fluid neurotransmitters showed low homovanillic acid and tetrahydrobiopterin. Levodopa-carbidopa resulted in dramatic improvement of gait. Dopamine/biopterin deficiency is a possible secondary manifestation of CLN2 mutations. Levodopa and dopamine agonists might be useful in treating these secondary abnormalities and improving quality of life in these patients. Show less