Not all fats are created equal: adipose vs. ectopic fat, implication in cardiometabolic diseases

Excessive fat expenditure in MCT-induced heart failure rats is associated with BMAL1/REV-ERBα circadian rhythmic loop disruption

Fat loss predicts adverse outcomes in advanced heart failure (HF). Disrupted circadian clocks are a primary cause of lipid metabolic issues, but it's unclear if this disruption affects fat expenditure in HF. To address this issue, we investigated the effects of disruption of the BMAL1/REV-ERBα circadian rhythmic loop on adipose tissue metabolism in HF.50 Wistar rats were initially divided into control (n = 10) and model (n = 40) groups. The model rats were induced with HF via monocrotaline (MCT) injections, while the control group received equivalent solvent injections. After establishing the HF model, the model group was further subdivided into four groups: normal rhythm (LD), inverted rhythm (DL), lentivirus vector carrying Bmal1 short hairpin RNA (LV-Bmal1 shRNA), and empty lentivirus vector control (LV-Control shRNA) groups, each with 10 rats. The DL subgroup was exposed to a reversed light-dark cycle of 8 h: 16 h (dark: light), while the rest adhered to normal light-dark conditions (light: dark 12 h: 12 h). Histological analyses were conducted using H&E, Oil Red O, and Picrosirius red stains to examine adipose and liver tissues. Immunohistochemical staining, RT-qPCR, and Western blotting were performed to detect markers of lipolysis, lipogenesis, and beiging of white adipose tissue (WAT), while thermogenesis indicators were detected in brown adipose tissue (BAT). The LD group rats exhibited decreased levels of BMAL1 protein, increased levels of REV-ERBα protein, and disrupted circadian circuits in adipose tissue compared to controls. Additionally, HF rats showed reduced adipose mass and increased ectopic lipid deposition, along with smaller adipocytes containing lower lipid content and fibrotic adipose tissue. In the LD group WAT, expression of ATGL, HSL, PKA, and p-PKA proteins increased, alongside elevated mRNA levels of lipase genes (Hsl, Atgl, Peripilin) and FFA β-oxidation genes (Cpt1, acyl-CoA). Conversely, lipogenic gene expression (Scd1, Fas, Mgat, Dgat2) decreased, while beige adipocyte markers (Cd137, Tbx-1, Ucp-1, Zic-1) and UCP-1 protein expression increased. In BAT, HF rats exhibited elevated levels of PKA, p-PKA, and UCP-1 proteins, along with increased expression of thermogenic genes (Ucp-1, Pparγ, Pgc-1α) and lipid transportation genes (Cd36, Fatp-1, Cpt-1). Plasma NT-proBNP levels were higher in LD rats, accompanied by elevated NE and IL-6 levels in adipose tissue. Remarkably, morphologically, the adipocytes in the DL and LV-Bmal1 shRNA groups showed reduced size and lower lipid content, while lipid deposition in the liver was more pronounced in these groups compared to the LD group. At the gene/protein level, the BMAL1/REV-ERBα circadian loop exhibited severe disruption in LV-Bmal1 shRNA rats compared to LD rats. Additionally, there was increased expression of lipase genes, FFA β oxidation genes, and beige adipocyte markers in WAT, as well as higher expression of thermogenic genes and lipid transportation genes in BAT. Furthermore, plasma NT-proBNP levels and adipose tissue levels of NE and IL-6 were elevated in LV-Bmal1 shRNA rats compared with LD rats. The present study demonstrates that disruption of the BMAL1/REV-ERBα circadian rhythmic loop is associated with fat expenditure in HF. This result suggests that restoring circadian rhythms in adipose tissue may help counteract disorders of adipose metabolism and reduce fat loss in HF.

A review on interplay between obesity, lipoprotein profile and nutrigenetics with selected candidate marker genes of type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus, a rapidly growing epidemic, and its frequently related complications demand global attention. The two factors commonly attributed to the epidemic are genetic factors and environmental factors. Studies indicate that the genetic makeup at an individual level and the environmental aspects influence the occurrence of the disease. However, there is insufficiency in understanding the mechanisms through which the gene mutations and environmental components individually lead to T2DM. Also, discrepancies have often been noted in the association of gene variants and type 2 diabetes when the gene factor is examined as a sole attribute to the disease.

STUDY

In this review initially, we have focused on the proposed ways through which CAPN10, FABP2, GLUT2, TCF7L2, and ENPP1 variants lead to T2DM along with the inconsistencies observed in the gene-disease association. The article also emphasizes on obesity, lipoprotein profile, and nutrition as environmental factors and how they lead to T2DM. Finally, the main objective is explored, the environment-gene-disease association i.e. the influence of each environmental factor on the aforementioned specific gene-T2DM relationship to understand if the disease-causing capability of the gene variants is exacerbated by environmental influences.

CONCLUSION

We found that environmental factors may influence the gene-disease relationship. Reciprocally, the genetic factors may alter the environment-disease relationship. To precisely conclude that the two factors act synergistically to lead to T2DM, more attention has to be paid to the combined influence of the genetic variants and environmental factors on T2DM occurrence instead of studying the influence of the factors separately.

Mediating Roles of hsCRP, TNF-α and Adiponectin on the Associations between Body Fat and Fatty Liver Disease among Overweight and Obese Adults

Simple Summary

Body fat has been reported to be related to a higher risk of fatty liver disease (FLD). However, few studies have explored the mediating roles of inflammatory biomarkers or adipokines on the relationships. This study examined the potential mediating effects of high sensitivity C-reactive protein (hsCRP), tumor necrosis factor-α (TNF-α) and adiponectin (APN) in relationships between body fat and FLD in overweight and obese adults. Additionally, gender and age differences were demonstrated. It was concluded that hsCRP has a significant mediating effect on the association between body fat percentage and FLD in females independent of potential covariates. It was also demonstrated that the mediation effect of hsCRP was only significant and more profound in relatively older adults (36–56 years, 38.3%), not significant in the young ones (19–35 years). TNF-α and APN were not significantly associated with body fat percentage or FLD, with no mediating effect on the association between body fat percentage and FLD observed in either gender. In conclusion, hsCRP was a potential mediator on the association between adiposity and FLD, and this mediation is gender-specific and age-specific. The authors hope that the findings could contribute to the further exploration of the inflammatory-related mechanism of obesity-associated FLD.

Abstract

Body fat has been reported to be associated with a higher risk of fatty liver disease (FLD). However, few studies have explored the mediating roles of an inflammatory biomarker or adipokine on the relationships. Here, we examined the potential mediating roles of high sensitivity C-reactive protein (hsCRP), tumor necrosis factor-α (TNF-α) and adiponectin (APN) in relationships between body fat and FLD in overweight and obese adults. Additionally, gender differences will be investigated. In total, 1221 participants aged 19–56 years were included in our study. Body fat percentage was measured with Dual Energy X-ray Absorptiometry (DEXA) and FLD by abdominal ultrasound. Mediation analysis was performed to assess the mediating effect of hsCRP, TNF-α and APN on the associations between BF (%) and FLD by gender differences. We found that hsCRP was significantly associated with body fat percentage in both genders (b = 0.2014, p < 0.0001 and b = 0.1804, p < 0.0001 for male and female, respectively), while hsCRP was associated with FLD only in the female group (b = 0.1609, p = 0.0109) but not in male group (b = 0.4800, p = 0.0603). We observed that hsCRP has a significant mediating effect on the association between body fat percentage and FLD (b = 0.0290, p = 0.0201, mediation ratio: 13.6%) in the female group independent of potential covariates (age, smoking, alcohol drinking and physical activity). TNF-α was not significantly associated with body fat percentage or FLD, with no mediating effect on the association between body fat percentage and FLD in either gender. In conclusion, there is a gender-specific mediation role of hsCRP in the association between body fat and FLD. HsCRP was a potential mediator on the association between adiposity and FLD in the female gender, but not in the male gender. Higher body fat was associated with a higher risk of FLD, and the inflammation level might play a potential mediating role in the association between body fat and FLD among female overweight and obese adults.

Antidyslipidemic Potential of Water-Soluble Polysaccharides of Ganoderma applanatum in MACAPOS-2-Induced Obese Rats

Increased consumption of high-calorie foods leads to obesity usually associated with metabolic disorders including diabetes, hyperglycemia, and dyslipidemia. Ganoderma applanatum is a nonedible mushroom traditionally used in West Cameroon for the treatment of many diseases including hypertension, diabetes, and hepatitis. This study was designed to investigate the antidyslipidemic potential of water-soluble polysaccharides of G. applanatum in MACAPOS-2- (maize, cassava, palm oil, and sugar) induced obese rats. For this purpose, obesity was induced on 6–8-week-old male Wistar rats with a local high-fat diet for four months. G. applanatum polysaccharides (GAPs) obtained by hot water extraction were orally administered to obese rats for two months at different dose levels (50, 100, and 150 mg/kg bodyweight), and its potential was investigated on food consumption, bodyweight gain, serum, and tissue lipids parameters. GAP extract increased the bodyweight gain by raising the food intake of obese rats. Furthermore, the administration of GAP extract at different dose levels significantly decreased the total cholesterol, triglyceride, low-density lipoprotein cholesterol levels, and the atherogenic index from 50 to 150 mg/kg bodyweight. Conversely, GAP extract improved the high-density lipoprotein cholesterol level in obese rats compared with untreated rats after two months' study period. These results indicated that GAP extract may be considered as a novel bioactive compound against dyslipidemia and its associated complications.

Deletion of Seipin Attenuates Vascular Function and the Anticontractile Effect of Perivascular Adipose Tissue

Seipin locates in endoplasmic reticulum (ER) and regulates adipogenesis and lipid droplet formation. Deletion of Seipin has been well-demonstrated to cause severe general lipodystrophy, however, its role in maintaining perivascular adipose tissue (PVAT) and vascular homeostasis has not been directly assessed. In the present study, we investigated the role of Seipin in mediating the anticontractile effect of PVAT and vascular function. Seipin expression in PVAT and associated vessels were detected by qPCR and western-blot. Seipin is highly expressed in PVAT, but hardly in vessels. Structural and functional alterations of PVAT and associated vessels were compared between Seipin^−/− mice and WT mice. In Seipin^−/− mice, aortic and mesenteric PVAT were significantly reduced in mass and adipose-derived relaxing factors (ADRFs) secretion, but increased in macrophage infiltration and ER stress, as compared with those in WT mice. Aortic and mesenteric artery rings from WT and Seipin^−/− mice were mounted on a wire myograph. Vasoconstriction and vasodilation were studied in vessels with and without PVAT. WT PVAT augmented relaxation but not Seipin^−/− PVAT, which suggest impaired anticontractile function in PVAT of Seipin^−/− mice. Thoracic aorta and mesenteric artery from Seipin^−/− mice had impaired contractility in response to phenylephrine (PHE) and relaxation to acetylcholine (Ach). In conclusion, Seipin deficiency caused abnormalities in PVAT morphology and vascular functions. Our data demonstrated for the first time that Seipin plays a critical role in maintaining PVAT function and vascular homeostasis.

Prolonged Chronic Consumption of a High Fat with Sucrose Diet Alters the Morphology of the Small Intestine

(1) The high-fat diet (HFD) of western countries has dramatic effect on the health of several organs, including the digestive tract, leading to the accumulation of fats that can also trigger a chronic inflammatory process, such as that which occurs in non-alcohol steatohepatitis. The effects of a HFD on the small intestine, the organ involved in the absorption of this class of nutrients, are still poorly investigated. (2) To address this aspect, we administered a combined HFD with sucrose (HFD w/Suc, fat: 58% Kcal) regimen (18 months) to mice and investigated the morphological and molecular changes that occurred in the wall of proximal tract of the small intestine compared to the intestine of mice fed with a standard diet (SD) (fat: 18% Kcal). (3) We found an accumulation of lipid droplets in the mucosa of HFD w/Suc-fed mice that led to a disarrangement of mucosa architecture. Furthermore, we assessed the expression of several key players involved in lipid metabolism and inflammation, such as perilipin, leptin, leptin receptor, PI3K, p-mTOR, p-Akt, and TNF-α. All these molecules were increased in HFD mice compared to the SD group. We also evaluated anti-inflammatory molecules like adiponectin, adiponectin receptor, and PPAR-γ, and observed their significant reduction in the HFD w/Suc group compared to the control. Our data are in line with the knowledge that improper eating habits present a primary harmful assault on the bowel and the entire body's health. (4) These results represent a promising starting point for future studies, helping to better understand the complex and not fully elucidated spectrum of intestinal alterations induced by the overconsumption of fat.

CT-based determination of excessive visceral adipose tissue is associated with an impaired survival in critically ill patients

Objective

Obesity is a negative prognostic factor for various clinical conditions. In this observational cohort study, we evaluated a CT-based assessment of the adipose tissue distribution as a potential non-invasive prognostic parameter in critical illness.

Methods

Routine CT-scans upon admission to the intensive care unit (ICU) were used to analyze the visceral and subcutaneous adipose tissue areas at the 3^rd lumbar vertebra in 155 patients. Results were correlated with various prognostic markers and both short-term- and overall survival. Multiple statistical tools were used for data analysis.

Results

We observed a significantly larger visceral adipose tissue area in septic patients compared to non-sepsis patients. Interestingly, patients requiring mechanical ventilation had a significantly higher amount of visceral adipose tissue correlating with the duration of mechanical ventilation. Moreover, both visceral and subcutaneous adipose tissue area significantly correlated with several laboratory markers. While neither the visceral nor the subcutaneous adipose tissue area was predictive for short-term ICU survival, patients with a visceral adipose tissue area above the optimal cut-off (241.4 cm²) had a significantly impaired overall survival compared to patients with a lower visceral adipose tissue area.

Conclusions

Our study supports a prognostic role of the individual adipose tissue distribution in critically ill patients. However, additional investigations need to confirm our suggestion that routine CT-based assessment of adipose tissue distribution can be used to yield further information on the patients’ clinical course. Moreover, future studies should address functional and metabolic analysis of different adipose tissue compartments in critical illness.

A review of the role of inositols in conditions of insulin dysregulation and in uncomplicated and pathological pregnancy

Inositols, a group of 6-carbon polyols, are highly bioactive molecules derived from diet and endogenous synthesis. Inositols and their derivatives are involved in glucose and lipid metabolism and participate in insulin-signaling, with perturbations in inositol processing being associated with conditions involving insulin resistance, dysglycemia and dyslipidemia such as polycystic ovary syndrome and diabetes. Pregnancy is similarly characterized by substantial and complex changes in glycemic and lipidomic regulation as part of maternal adaptation and is also associated with physiological alterations in inositol processing. Disruptions in maternal adaptation are postulated to have a critical pathophysiological role in pregnancy complications such as gestational diabetes and pre-eclampsia. Inositol supplementation has shown promise as an intervention for the alleviation of symptoms in conditions of insulin resistance and for gestational diabetes prevention. However, the mechanisms behind these affects are not fully understood. In this review, we explore the role of inositols in conditions of insulin dysregulation and in pregnancy, and identify priority areas for research. We particularly examine the role and function of inositols within the maternal-placental-fetal axis in both uncomplicated and pathological pregnancies. We also discuss how inositols may mediate maternal-placental-fetal cross-talk, and regulate fetal growth and development, and suggest that inositols play a vital role in promoting healthy pregnancy.

Perivascular Adipose Tissue Regulates Vascular Function by Targeting Vascular Smooth Muscle Cells

Adipose tissues are present at multiple locations in the body. Most blood vessels are surrounded with adipose tissue which is referred to as perivascular adipose tissue (PVAT). Similarly to adipose tissues at other locations, PVAT harbors many types of cells which produce and secrete adipokines and other undetermined factors which locally modulate PVAT metabolism and vascular function. Uncoupling protein-1, which is considered as a brown fat marker, is also expressed in PVAT of rodents and humans. Thus, compared with other adipose tissues in the visceral area, PVAT displays brown-like characteristics. PVAT shows a distinct function in the cardiovascular system compared with adipose tissues in other depots which are not adjacent to the vascular tree. Growing and extensive studies have demonstrated that presence of normal PVAT is required to maintain the vasculature in a functional status. However, excessive accumulation of dysfunctional PVAT leads to vascular disorders, partially through alteration of its secretome which, in turn, affects vascular smooth muscle cells and endothelial cells. In this review, we highlight the cross talk between PVAT and vascular smooth muscle cells and its roles in vascular remodeling and blood pressure regulation.

Targeting Abdominal Obesity and Its Complications with Dietary Phytoestrogens

In the assessment of the health risk of an obese individual, both the amount of adipose tissue and its distribution and metabolic activity are essential. In adults, the distribution of adipose tissue differs in a gender-dependent manner and is regulated by sex steroids, especially estrogens. Estrogens affect adipocyte differentiation but are also involved in the regulation of the lipid metabolism, insulin resistance, and inflammatory activity of the adipose tissue. Their deficiency results in unfavorable changes in body composition and increases the risk of metabolic complications, which can be partially reversed by hormone replacement therapy. Therefore, the idea of the supplementation of estrogen-like compounds to counteract obesity and related complications is compelling. Phytoestrogens are natural plant-derived dietary compounds that resemble human estrogens in their chemical structure and biological activity. Supplementation with phytoestrogens may confer a range of beneficial effects. However, results of studies on the influence of phytoestrogens on body composition and prevalence of obesity are inconsistent. In this review, we present data from in vitro, animal, and human studies regarding the role of phytoestrogens in adipose tissue development and function in the context of their potential application in the prevention of visceral obesity and related complications.

Review: the Roles and Mechanisms of Glycoprotein 130 Cytokines in the Regulation of Adipocyte Biological Function

Chronic low-grade inflammation is now widely accepted as one of the most important contributors to metabolic disorders. Glycoprotein 130 (gp130) cytokines are involved in the regulation of metabolic activity. Studies have shown that several gp130 cytokines, such as interleukin-6 (IL-6), leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor (CNTF), and cardiotrophin-1 (CT-1), have divergent effects on adipogenesis, lipolysis, and insulin sensitivity as well as food intake. In this review, we will summarize the present knowledge about gp130 cytokines, including IL-6, LIF, CNTF, CT-1, and OSM, in adipocyte biology and metabolic activities in conditions such as obesity, cachexia, and type 2 diabetes. It is valuable to explore the diverse actions of these gp130 cytokines on the regulation of the biological functions of adipocytes, which will provide potential therapeutic targets for the treatment of obesity and cachexia.

Relationship of para- and perirenal fat and epicardial fat with metabolic parameters in overweight and obese subjects

BACKGROUND

The accumulation of visceral body fat, has been shown to be associated with higher risk of metabolic and cardiovascular disease. This study was addressed to examine whether para- and perirenal fat thickness and epicardial fat thickness were correlated with anthropometric- and cardiometabolic risk factors.

METHODS

A cohort of 102 uncomplicated overweight and obese patients was examined. BMI, waist circumference, blood pressure, fasting insulin, glucose, triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol serum levels, and insulin resistance (assessed by HOMA_IR) were measured. Para- and perirenal fat thickness (PUFT) and epicardial fat thickness (EUFT) were measured by ultrasounds.

RESULTS

PUFT was positively correlated with BMI (p < 0.001), waist circumference (p < 0.001), insulin (p < 0.001), HOMA_IR (p < 0.001), triglycerides (p < 0.05), systolic (p < 0.05) and diastolic (p < 0.05) blood pressure, and negatively correlated with HDL-cholesterol (p < 0.01). EUFT was positively associated with age (p < 0.01), BMI (p < 0.001), waist circumference (p < 0.001), systolic (p < 0.01) and diastolic (p < 0.001) blood pressure, and LDL-cholesterol (p < 0.05). A multivariate analysis by multiple linear regression was performed, and the final model showed a direct association of waist circumference with both PUFT and EUFT, a correlation of PUFT with HOMA_IR (positive) and HDL-cholesterol (negative), and a direct association of EUFT (both long axis and short axis) with LDL-cholesterol. All these correlations were independent of other anthropometric, metabolic and hemodynamic parameters.

CONCLUSIONS

This study shows that accumulation of central fat in apparently healthy overweight and obese subjects is associated to a simultaneous increase of pararenal, perirenal and epicardial fat. Moreover, it shows that only para- and perirenal fat is independently associated to insulin resistance and lower HDL-cholesterol, and only epicardial fat is independently associated to higher LDL cholesterol. Level of evidence Level V, cross-sectional descriptive study.

Exercise training improves intramuscular triglyceride lipolysis sensitivity in high-fat diet induced obese mice

Background

The purpose of this study was to determine whether regular exercise training enhances intramuscular triglyceride (IMTG) lipolysis sensitivity during consumption of a continued high-fat diet by exploring changes in biochemical factors activated by IMTG lipolysis.

Methods

Male C57BL/6 mice aged 4 weeks were randomly divided into a high-fat diet group (HF) to induce obesity for 6 weeks and a control (CO) group. Thereafter, the HF group was divided into a high-fat diet group (HF) and high-fat diet + training group (HFT). The HFT group was trained on an animal treadmill 40 min/day, 5 days/week for 8 weeks. PKA, Plin5, p-Plin5, CGI-58, ATGL, and HSL were analyzed to investigate IMTG sensitivity by western blotting.

Results

PKA, CGI-58, and HSL protein levels in the HF group were significantly lower than those in the CO group (p < 0.05). However, PKA, CGI-58, and HSL protein levels in the HFT group were significantly higher than those in the HF group, and ATGL and p-Plin5 protein levels as well as the p-Plin5/Plin5 ratio in the HFT group were significantly higher than those in the HF group (p < 0.05). In addition, the HF group showed a significantly higher IMTG volume than the CO and HFT groups (p < 0.05).

Conclusions

These results suggest that in an obese mouse model, 8 weeks of treadmill exercise contributes to decreased IMTG volume by activating lipolysis factors, such as PKA, PLIN5, CGI-58, and lipases. Therefore, regular exercise training may play an important role in obesity treatment by increasing IMTG lipolysis sensitivity.

The Fat of the Matter: Obesity and Visceral Adiposity in Treated HIV Infection

PURPOSE OF REVIEW

The aim of this review is to summarize knowledge of the prevalence, relevant physiology, and consequences of obesity and visceral adiposity in HIV-infected adults, including highlighting gaps in current knowledge and future research directions.

RECENT FINDINGS

Similar to the general population, obesity prevalence is increasing among HIV-infected persons, and obesity and visceral adiposity are associated with numerous metabolic and inflammatory sequelae. However, HIV- and antiretroviral therapy (ART)-specific factors may contribute to fat gain and fat quality in treated HIV infection, particularly to the development of visceral adiposity, and sex differences may exist. Obesity and visceral adiposity commonly occur in HIV-infected persons and have significant implications for morbidity and mortality. Future research should aim to better elucidate the HIV- and ART-specific contributors to obesity and visceral adiposity in treated HIV infection, with the goal of developing targeted therapies for the prevention and treatment of obesity and visceral adiposity in the modern ART era.

Deciphering adipose tissue heterogeneity

Obesity is an excess accumulation of adipose tissue mass, and, together with its sequelae, in particular type II diabetes and metabolic syndrome, obesity presents a major health crisis. Although obesity is simply caused by increased adipose mass, the heterogeneity of adipose tissue in humans means that the response to increased energy balance is highly complex. Individual subjects with similar phenotypes may respond very differently to the same treatments; therefore, obesity may benefit from a personalized precision medicine approach. The variability in the development of obesity is indeed driven by differences in sex, genetics, and environment, but also by the various types of adipose tissue as well as the different cell types that compose it. By describing the distinct cell populations that reside in different fat depots, we can interpret the complex effect of these various players in the maintenance of whole-body energy homeostasis. To further understand adipose tissue, adipogenic differentiation and the transcriptional program of lipid accumulation must be investigated. As the cell- and depot-specific functions are described, they can be placed in the context of energy excess to understand how the heterogeneity of adipose tissue shapes individual metabolic status and condition.

Lipid metabolism in patients with chronic hyperglycemia after an episode of acute pancreatitis

BACKGROUND

The importance of dyslipidemia is well recognized in the context of both risk factor for acute pancreatitis and prognostic factor for its in-hospital outcomes. With a growing appreciation of post-pancreatitis diabetes mellitus, there is a need to catalogue changes in lipid metabolism after hospitalization due to an acute pancreatitis attack and their associations with glucose metabolism.

OBJECTIVE

To investigate lipid metabolism in patients with impaired glucose homeostasis following acute pancreatitis.

METHODS

There were two study groups: newly diagnosed chronic hyperglycemia or normoglycemia after acute pancreatitis. During the fasting state, venous blood samples were collected to analyse markers of lipid metabolism (triglycerides, glycerol, low density lipoprotein, high density lipoprotein, total cholesterol, free fatty acids, and apolipoprotein-B) and glucose metabolism (HbA1c, insulin, index of adipose tissue insulin resistance (Adipo-IR), and HOMA-IR). Binary logistic and linear regression analyses were conducted, and potential confounders were adjusted for in multivariate analyses.

RESULTS

The study included 64 patients with normoglycemia and 19 - with chronic hyperglycemia. Glycerol was significantly associated with the development of chronic hyperglycemia in both unadjusted (p=0.02) and adjusted (p=0.006) models. Triglycerides were significantly associated with the development of chronic hyperglycemia in adjusted (p=0.019) model. Other markers of lipid metabolism did not differ significantly between the two groups. None of the markers of lipid metabolism was significantly associated with Adipo-IR or HOMA-IR.

CONCLUSION

Overall, patients with chronic hyperglycemia after acute pancreatitis appear to have a lipid profile indicative of an up-regulation of lipolysis, which is not significantly affected by either general or adipose tissue-specific insulin resistance.

Cardiac Autonomic Modulation and the Kinetics of Heart Rate Responses in the On- and Off-Transient during Exercise in Women with Metabolic Syndrome

Objective: To test whether women with metabolic syndrome (MS) have impairments in the on- and off-transients during an incremental test and to study whether any of the MS components are independently associated with the observed responses.

Research Design and Methods: Thirty-six women aged 35–55 years were divided into a group with MS (MSG, n = 19) and a control group (CG, n = 17). R-R intervals (RRi) and heart rate variability (HRV) were calculated on a beat-to-beat basis and the heart rate (HR) at the on- and off-transient were analyzed during an incremental cardiopulmonary exercise test (CPET).

Results: MSG showed lower aerobic capacity and lower parasympathetic cardiac modulation at rest compared with CG. HR values in on-transient phase were significantly lower in MSG compared with CG. The exponential amplitudes “amp” and the parameters “τ” [speed of heart rate recovery (HRR)] were lower in MSG. MSG exhibited higher HR values in comparison to CG during the off-transient indicating a slower HRR. In MSG, there was an inverse and significant correlation between fasting plasma vs. ΔF and glucose vs. exponential “τ” of HRR dynamics.

Conclusion: MS is associated with poor heart rate kinetics. The altered HR kinetics seems to be related to alterations in cardiac parasympathetic modulation, and glucose metabolism seems to be the major determinant.

The why, when and how of lipid droplet diversity

Lipid droplets are the universal cellular organelles for the transient or long-term storage of lipids. The number, size and composition of lipid droplets vary greatly within cells in a homogenous population as well as in different cell types. The variability of intracellular lipid-storage organelles reflects the diversification of lipid droplet composition and function. Lipid droplet diversification results, for example, in two cellular lipid droplet populations that are prone to diminish and grow, respectively. The aberrant accumulation or depletion of lipids are hallmarks or causes of various human pathologies. Thus, a better understanding of the origins of lipid droplet diversification is not only a fascinating cell biology question but also potentially serves to improve comprehension of pathologies that entail the accumulation of lipids. This Commentary covers the lipid droplet life cycle and highlights the early steps during lipid droplet biogenesis, which we propose to be the potential driving forces of lipid droplet diversification.

Differential Role of Adipose Tissues in Obesity and Related Metabolic and Vascular Complications

This review focuses on the contribution of white, brown, and perivascular adipose tissues to the pathophysiology of obesity and its associated metabolic and vascular complications. Weight gain in obesity generates excess of fat, usually visceral fat, and activates the inflammatory response in the adipocytes and then in other tissues such as liver. Therefore, low systemic inflammation responsible for insulin resistance contributes to atherosclerotic process. Furthermore, an inverse relationship between body mass index and brown adipose tissue activity has been described. For these reasons, in recent years, in order to combat obesity and its related complications, as a complement to conventional treatments, a new insight is focusing on the role of the thermogenic function of brown and perivascular adipose tissues as a promising therapy in humans. These lines of knowledge are focused on the design of new drugs, or other approaches, in order to increase the mass and/or activity of brown adipose tissue or the browning process of beige cells from white adipose tissue. These new treatments may contribute not only to reduce obesity but also to prevent highly prevalent complications such as type 2 diabetes and other vascular alterations, such as hypertension or atherosclerosis.

Diverse properties of the mesothelial cells in health and disease

Mesothelial cells (MCs) form the superficial anatomic layer of serosal membranes, including pleura, pericardium, peritoneum, and the tunica of the reproductive organs. MCs produce a protective, non-adhesive barrier against physical and biochemical damages. MCs express a wide range of phenotypic markers, including vimentin and cytokeratins. MCs play key roles in fluid transport and inflammation, as reflected by the modulation of biochemical markers such as transporters, adhesion molecules, cytokines, growth factors, reactive oxygen species and their scavengers. MCs synthesize extracellular matrix related molecules, and the surface of MC microvilli secretes a highly hydrophilic protective barrier, "glycocalyx", consisting mainly of glycosaminoglycans. MCs maintain a balance between procoagulant and fibrinolytic activation by producing a whole range of regulators, can synthetize fibrin and therefore form adhesions. Synthesis and recognition of hyaluronan and sialic acids might be a new insight to explain immunoactive and immunoregulatory properties of MCs. Epithelial to mesenchymal transition of MCs may involve serosal repair and remodeling. MCs might also play a role in the development and remodeling of visceral adipose tissue. Taken together, MCs play important roles in health and disease in serosal cavities of the body. The mesothelium is not just a membrane and should be considered as an organ.

The Subtle Balance between Lipolysis and Lipogenesis: A Critical Point in Metabolic Homeostasis

Excessive accumulation of lipids can lead to lipotoxicity, cell dysfunction and alteration in metabolic pathways, both in adipose tissue and peripheral organs, like liver, heart, pancreas and muscle. This is now a recognized risk factor for the development of metabolic disorders, such as obesity, diabetes, fatty liver disease (NAFLD), cardiovascular diseases (CVD) and hepatocellular carcinoma (HCC). The causes for lipotoxicity are not only a high fat diet but also excessive lipolysis, adipogenesis and adipose tissue insulin resistance. The aims of this review are to investigate the subtle balances that underlie lipolytic, lipogenic and oxidative pathways, to evaluate critical points and the complexities of these processes and to better understand which are the metabolic derangements resulting from their imbalance, such as type 2 diabetes and non alcoholic fatty liver disease.