The Role of Epicardial Fat in Pericardial Diseases

Short-Term Postnatal Overfeeding Induces Long-Lasting Cardiometabolic Syndrome in Mature and Old Mice Associated with Increased Sensitivity to Myocardial Infarction

SCOPE

Perinatal nutritional disturbances may "program" an increased cardio-metabolic risk in adulthood; however, few experimental studies have explored their effects on mature and/or old animal. This study aims to investigate the influence of postnatal overfeeding (PNOF) on cardiac function, sensitivity to ischemia-reperfusion (I-R) injury in vivo, glucose metabolism, and metabolic profile of pericardial adipose tissue (PAT) in young (4 months), adult (6 months), old (12 months), and very old (18 months) male mice.

METHODS AND RESULTS

Two days after birth, PNOF is induced by adjusting the litter size of C57BL/6 male mice to three pups/mother, while the normally fed (NF) control group is normalized to nine pups/mother. After weaning, all mice have free access to standard diet. Glucose/insulin tests and in vivo myocardial I-R injury are conducted on mice aged from 2 to 12 months, while echocardiography is performed at all ages up to 18 months. PNOF mice exhibit an early and persistent 10-20% increase in body weight and a 10% decrease in left ventricular ejection fraction throughout their lifespan. In PNOF mice aged 4, 6, and 12 months, glucose intolerance and insulin resistance are observed, as well as a 27-34% increase in infarct size. This is accompanied by a higher PAT mass with increased inflammatory status.

CONCLUSION

Short-term PNOF results in nutritional programming, inducing long-lasting alterations in glucose metabolism and cardiac vulnerability in male mice, lasting up to 12 months.

Cardiac fat pat change after laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass surgery: a systematic review and meta-analysis

Cardiac fat pad is a metabolically active organ that plays a role in energy homeostasis and cardiovascular diseases and generates inflammatory cytokines. Many studies have shown remarkable associations between cardiac fat thickness and cardiovascular diseases, making it a valuable target for interventions. Our meta-analysis aimed to investigate the effects of the 2 most popular bariatric surgeries (sleeve gastrectomy [SG] and Roux-en-Y gastric bypass [RYGB]) in cardiac fat pad reduction. A systematic review of the literature was done by searching in Scopus, Web of Science, Cochrane, and PubMed for articles published by September 16, 2022. This review followed the meta-analysis rules based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. Nineteen studies met the inclusion criteria out of 128 potentially useful studies, including a total number of 822 patients. The results of subgroup analysis on the type of surgery showed that bariatric surgeries decreased the mean fat pad diameter, but the reduction was greater in SG than in RYGB. Epicardial and pericardial fat type showed a significant decrease of fat pad diameter. The results of subgroup analysis indicated RYGB had a significant reduction in mean fat pad volume. Computed tomography scan and cardiac magnetic resonance imaging showed a significant reduction of the mean cardiac fat pad volume. Epicardial and paracardial fat type showed a significant decrease in volume. The cardiac fat pad diameter and volume were significantly reduced after bariatric surgeries. SG showed greater reduction in fat pad diameter in comparison with RYGB, and RYGB had a significant reduction in mean fat pad volume.

The Pivotal Role of Adipocyte-Na K peptide in Reversing Systemic Inflammation in Obesity and COVID-19 in the Development of Heart Failure

This review summarizes data from several laboratories that have demonstrated a role of the Na/K-ATPase, specifically its α1 subunit, in the generation of reactive oxygen species (ROS) via the negative regulator of Src. Together with Src and other signaling proteins, the Na/K-ATPase forms an oxidant amplification loop (NKAL), amplifies ROS, and participates in cytokines storm in obesity. The development of a peptide fragment of the α1 subunit, NaKtide, has been shown to negatively regulate Src. Several groups showed that the systemic administration of the cell permeable modification of NaKtide (pNaKtide) or its selective delivery to fat tissue-adipocyte specific expression of NaKtide-ameliorate the systemic elevation of inflammatory cytokines seen in chronic obesity. Severe acute respiratory syndrome - coronavirus 2 (SARS-CoV-2), the RNA Coronavirus responsible for the COVID-19 global pandemic, invades cells via the angiotensin converting enzyme 2 (ACE-2) receptor (ACE2R) that is appended in inflamed fat tissue and exacerbates the formation of the cytokines storm. Both obesity and heart and renal failure are well known risks for adverse outcomes in patients infected with COVID-19. White adipocytes express ACE-2 receptors in high concentration, especially in obese patients. Once the virus invades the white adipocyte cell, it creates a COVID19-porphyrin complex which degrades and produces free porphyrin and iron and increases ROS. The increased formation of ROS and activation of the NKAL results in a further potentiated formation of ROS production, and ultimately, adipocyte generation of more inflammatory mediators, leading to systemic cytokines storm and heart failure. Moreover, chronic obesity also results in the reduction of antioxidant genes such as heme oxygenase-1 (HO-1), increasing adipocyte susceptibility to ROS and cytokines. It is the systemic inflammation and cytokine storm which is responsible for many of the adverse outcomes seen with COVID-19 infections in obese subjects, leading to heart failure and death. This review will also describe the potential antioxidant drugs and role of NaKtide and their demonstrated antioxidant effect used as a major strategy for improving obesity and epicardial fat mediated heart failure in the context of the COVID pandemic.

BMPER is upregulated in obesity and seems to have a role in pericardial adipose stem cells

Pericardial adipose tissue (PAT), a visceral fat depot enveloping the heart, is an active endocrine organ and a source of free fatty acids and inflammatory cytokines. As in other fat adult tissues, PAT contains a population of adipose stem cells; however, whether these cells and/or their environment play a role in physiopathology is unknown. We analyzed several stem cell-related properties of pericardial adipose stem cells (PSCs) isolated from obese and ex-obese mice. We also performed RNA-sequencing to profile the transcriptional landscape of PSCs isolated from the different diet regimens. Finally, we tested whether these alterations impacted on the properties of cardiac mesoangioblasts isolated from the same mice. We found functional differences between PSCs depending on their source: specifically, PSCs from obese PSC (oPSC) and ex-obese PSC (dPSC) mice showed alterations in apoptosis and migratory capacity when compared with lean, control PSCs, with increased apoptosis in oPSCs and blunted migratory capacity in oPSCs and dPSCs. This was accompanied by different gene expression profiles across the cell types, where we identified some genes altered in obese conditions, such as BMP endothelial cell precursor-derived regulator (BMPER), an important regulator of BMP-related signaling pathways for endothelial cell function. The importance of BMPER in PSCs was confirmed by loss- and gain-of-function studies. Finally, we found an altered production of BMPER and some important chemokines in cardiac mesoangioblasts in obese conditions. Our findings point to BMPER as a potential new regulator of PSC function and suggest that its dysregulation could be associated with obesity and may impact on cardiac cells.

Developmental programming: Adipose depot-specific changes and thermogenic adipocyte distribution in the female sheep

Prenatal testosterone (T)-treated female sheep exhibit an enhanced inflammatory and oxidative stress state in the visceral adipose tissue (VAT) but not in the subcutaneous (SAT), while surprisingly maintaining insulin sensitivity in both depots. In adult sheep, adipose tissue is predominantly composed of white adipocytes which favor lipid storage. Brown/beige adipocytes that make up the brown adipose tissue (BAT) favor lipid utilization due to thermogenic uncoupled protein 1 expression and are interspersed amidst white adipocytes, more so in epicardiac (ECAT) and perirenal (PRAT) depots. The impact of prenatal T-treatment on ECAT and PRAT depots are unknown. As BAT imparts a metabolically healthy phenotype, the depot-specific impact of prenatal T-treatment on inflammation, oxidative stress, differentiation and insulin sensitivity could be dictated by the distribution of brown adipocytes. This hypothesis was tested by assessing markers of oxidative stress, inflammation, adipocyte differentiation, fibrosis and thermogenesis in adipose depots from control and prenatal T (100  mg T propionate twice a week from days 30-90 of gestation) -treated female sheep at 21 months of age. Our results show prenatal T-treatment induces depot-specific changes in inflammation, oxidative stress state, collagen accumulation, and differentiation with changes being more pronounced in the VAT. Prenatal T-treatment also increased thermogenic gene expression in all depots indicative of increased browning with effects being more prominent in VAT and SAT. Considering that inflammatory and oxidative stress are also elevated, the increased brown adipocyte distribution is likely a compensatory response to maintain insulin sensitivity and function of organs in the proximity of respective depots.

Leptin Expression in Human Epicardial Adipose Tissue Is Associated with Local Coronary Atherosclerosis

Background

Leptin is an adipokine related to overweight and cardiovascular diseases. However, the leptin expression level in epicardial adipose tissue (EAT) of humans and its association with coronary atherosclerosis has never been investigated.

Material/Methods

Patients receiving cardiac surgery were divided into a coronary artery disease group (CAD group) and a non-CAD group (NCAD group). Blood samples from coronary vein, biopsies of subcutaneous adipose tissue (SAT), and EAT were acquired during the surgery. Serum leptin level and leptin level in EAT and SAT were tested with ELISA, quantitative PCR, and immunohistochemistry and were compared between the CAD group and NCAD group, as well as between stenosis and non-stenosis subgroups. Logistic regression analysis was performed to explore the risk factors for coronary artery stenosis.

Results

No statistically significant differences were found in demographic and clinical data between groups (all P>0.05). Serum leptin concentration and leptin expression in EAT and SAT of the CAD group were much higher in than in the NCAD group (all P<0.05). In subgroup analysis, there was no difference in serum leptin and expression in SAT of stenosis and non-stenosis patients (All P>0.05). The leptin expression level in EAT of stenosis patients was significantly higher than in non-stenosis patients (P=0.0431). By multivariate logistic regression analysis, we demonstrated that leptin expression level in EAT was an independent risk factor for coronary artery stenosis [OR=1.09, 95%CI (1.01±1.18), P=0.031].

Conclusions

Leptin expression in EAT and SAT were both increased for CAD patients. Leptin expression in EAT was an independent risk factor for coronary atherosclerosis in the adjacent artery, while leptin in SAT was not associated.

Stem cells from human cardiac adipose tissue depots show different gene expression and functional capacities

BACKGROUND

The composition and function of the adipose tissue covering the heart are poorly known. In this study, we have investigated the epicardial adipose tissue (EAT) covering the cardiac ventricular muscle and the EAT covering the left anterior descending artery (LAD) on the human heart, to identify their resident stem cell functional activity.

METHODS

EAT covering the cardiac ventricular muscle was isolated from the apex (avoiding areas irrigated by major vessels) of the heart (ventricular myocardium adipose tissue (VMAT)) and from the area covering the epicardial arterial sulcus of the LAD (PVAT) in human hearts excised during heart transplant surgery. Adipose stem cells (ASCs) from both adipose tissue depots were immediately isolated and phenotypically characterized by flow cytometry. The different behavior of these ASCs and their released secretome microvesicles (MVs) were investigated by molecular and cellular analysis.

RESULTS

ASCs from both VMAT (mASCs) and the PVAT (pASCs) were characterized by the expression of CD105, CD44, CD29, CD90, and CD73. The angiogenic-related genes VEGFA, COL18A1, and TF, as well as the miRNA126-3p and miRNA145-5p, were analyzed in both ASC types. Both ASCs were functionally able to form tube-like structures in three-dimensional basement membrane substrates. Interestingly, pASCs showed a higher level of expression of VEGFA and reduced level of COL18A1 than mASCs. Furthermore, MVs released by mASCs significantly induced human microvascular endothelial cell migration.

CONCLUSION

Our study indicates for the first time that the resident ASCs in human epicardial adipose tissue display a depot-specific angiogenic function. Additionally, we have demonstrated that resident stem cells are able to regulate microvascular endothelial cell function by the release of MVs.

Sodium-glucose co-transporter-2 inhibitors (SGLT2i) use and risk of amputation: an expert panel overview of the evidence

Sodium-glucose co-transporter-2 inhibitors (SGLT2i) are oral antidiabetic agents that exert their glucose-lowering effect by increasing renal excretion of glucose. These drugs have been reported to beneficially affect cardiovascular (CV) and renal outcomes. However, concerns have recently been raised in relation to increased risk of lower-extremities amputation with canagliflozin and it remains unclear whether and to what extent this side effect could also occur with other SGLT2i. The present expert panel overview focuses on the three SGLT2i available and widely used in the US and Europe, i.e. empagliflozin, canagliflozin and dapagliflozin and only refers briefly to other SGLT2i for which less data are available. The results of large CV outcome trials with these SGLT2i are presented, focusing specifically on the data in relation to amputation risk. The potential pathophysiological mechanisms involved in this side effect are discussed. Furthermore, available data reporting amputation cases in SGLT2i users are critically reviewed. The expert panel concludes that, based on current data, increased amputation risk seems to be related only to canagliflozin, thus representing a drug-effect rather than a SGLT2i class-effect. The exact pathways underlying this drug-induced adverse event, possibly related to off-target drug effects rather than SGLT2 inhibition per se, should be elucidated in future studies. Continuous monitoring and pharmacovigilance is necessary and head to head trials would also be essential to provide definitive conclusions.