Statins decrease leptin expression in human white adipocytes

The effect of hydrophilic statins on adiponectin, leptin, visfatin, and vaspin levels in streptozocin-induced diabetic rats

Statins may affect glucose metabolism through adipokines. The aim of this study was to measure the effects of hydrophilic statins on the levels of several adipokines in diabetic rats. Wistar albino rats were divided into four groups: healthy control, untreated diabetic, diabetic treated with pravastatin, and diabetic treated with rosuvastatin. Diabetes was induced by intraperitoneal injection of STZ. Thereafter, 20 mg/kg/day doses of either pravastatin or rosuvastatin were administered to the treated diabetic rats for 8 weeks. At the end of the experiment, the body weights, fasting blood glucose levels, serum insulin levels, and insulin resistance, as well as the serum adiponectin, leptin, visfatin, and vaspin levels, were measured. Fasting blood glucose and insulin resistance levels were significantly higher, whereas insulin levels and body weight were significantly lower in the untreated diabetic group than in the control group. Diabetes caused significant decreases in adiponectin, leptin, and vaspin levels but a significant increase in visfatin levels. Pravastatin treatment significantly increased body weight and decreased fasting blood glucose levels, whereas rosuvastatin decreased body weight but did not affect fasting blood glucose levels. Pravastatin caused significant increases in both adiponectin and vaspin levels. However, rosuvastatin did not affect the adiponectin level but caused a significant decrease in the vaspin levels. Both pravastatin and rosuvastatin treatments decreased the leptin and visfatin levels. In conclusion, pravastatin is more effective at improving fasting blood glucose levels and body weight in diabetic rats, probably by increasing adiponectin and vaspin levels.

Unraveling the metabolic heterogeneity and commonality in senescent cells using systems modeling

Cellular senescence is a key contributor to aging and aging-related diseases, but its metabolic profiles are not well understood. Here, we performed a systematic analysis of the metabolic features of four types of cellular senescence (replication, irradiation, reactive oxygen species [ROS], and oncogene) in 12 cell lines using genome-wide metabolic modeling and meta-analysis. We discovered that replicative and ROS-induced senescence share a common metabolic signature, marked by decreased lipid metabolism and downregulated mevalonate pathway, while irradiation and oncogene-induced senescence exhibit more heterogeneity and divergence. Our genome-wide knockout simulations showed that enhancing the mevalonate pathway, by administrating mevalonate for instance, could reverse the metabolic alterations associated with senescence and human tissue aging, suggesting a potential anti-aging or lifespan-extending effect. Indeed, the experiment in Caenorhabditis elegans showed that administrating mevalonate significantly increased the lifespan. Our study provides a new insight into the metabolic landscape of cell senescence and identifies potential targets for anti-aging interventions.

Bempedoic Acid for Prevention of Cardiovascular Events in People With Obesity: A CLEAR Outcomes Subset Analysis

BACKGROUND

Obesity and hypercholesterolemia independently increase cardiovascular disease risk. This analysis evaluated the efficacy and safety of bempedoic acid in people with obesity participating in the CLEAR (Cholesterol Lowering via Bempedoic Acid [ECT1002], an ACL-Inhibiting Regimen) Outcomes trial.

METHODS

CLEAR Outcomes randomized 13 970 patients to daily bempedoic acid 180 mg or placebo. Exploratory outcomes including major adverse cardiovascular events-4 (cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or coronary revascularization), low-density lipoprotein cholesterol, hs-CRP (high-sensitivity C-reactive protein), weight change, and safety were assessed over a median of 40.7 months in 6177 patients with baseline body mass index ≥30 kg/m2.

RESULTS

In people with obesity, bempedoic acid resulted in placebo-corrected reductions in low-density lipoprotein cholesterol of -22.5% and hs-CRP of -23.2% at 6 months. Bempedoic acid treatment resulted in a major adverse cardiovascular events-4 reduction of 23% (hazard ratio [HR], 0.77 [95% CI, 0.67-0.89]) versus placebo. Nonfatal and fatal MI were reduced by 32% (HR, 0.68 [95% CI, 0.53-0.86]), coronary revascularization was reduced by 24% (HR, 0.76 [95% CI, 0.63-0.92]), and fatal and nonfatal stroke were reduced by 36% (HR, 0.64 [95% CI, 0.45-0.89]) compared with placebo. At month 36, mean±SD change in weight from baseline was -2.3 (6.3) kg for bempedoic acid and -1.4 (6.1) kg for placebo. Adverse events were reported in 87.4% of bempedoic acid patients and 86.7% of placebo patients. The mean±SD change in uric acid at 6 months was 0.81 (1.26) mg/dL for bempedoic acid versus -0.04 (1.05) mg/dL for placebo.

CONCLUSIONS

Among people with obesity, bempedoic acid reduced major adverse cardiovascular events, low-density lipoprotein cholesterol, and hs-CRP, with a safety profile consistent with previous reports.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique Identifier: NCT02993406.

Effect of Nuts on Anthropometric and Glycemic Indexes and Blood Pressure in Secondary Cardiovascular Prevention: A Systematic Review and Meta-analysis of Randomized Controlled Trials

CONTEXT

Nut-enriched diets have a positive impact on cardiovascular risk factors, such as body mass, blood pressure, and fasting blood glucose. However, studies in individuals undergoing secondary cardiovascular prevention show controversial results.

OBJECTIVE

This systematic review with meta-analysis assessed the effect of nut supplementation on anthropometric, glycemic, and blood pressure indices in patients with atherosclerotic cardiovascular disease, as well as the frequency of adverse events.

DATA SOURCES

Six databases were used for the search-PubMed, Cochrane Library, EMBASE, BVS (Biblioteca Virtual da Saude), Web of Science, and ClinicalTrials.gov-until February 2023, with no language restrictions.

DATA EXTRACTION

The Cochrane Handbook for Systematic Reviews of Interventions methodology and the PICOS (Population, Intervention, Comparison, Outcome, Setting/design) strategy were used. Seven independent reviewers were involved in data extraction and resolution of disagreements. Certainty of the evidence was evaluated using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system.

DATA ANALYSIS

From 5187 records identified, 6 publications containing data referring to 5 randomized clinical trials (n = 436) were included in the final analyses. The nuts evaluated were almonds, pecans, Brazil nuts, and mixed nuts, with portions that varied between 5 g and 85 g (median: 30 g/day). The intervention period varied between 6 and 12 weeks. The nuts had no effect on fasting glucose and anthropometric indices, although the certainty of the evidence for most of these outcomes was low or very low. They also had no effect on systolic (mean difference [MD]: -1.16 mmHg [95% CI, -5.68 to 3.35], I2 = 0%-moderate certainty of evidence) or diastolic (MD: 0.10 mmHg [95% CI, -2.30 to 2.51], I2 = 0%-high certainty of evidence) blood pressure. It was not possible to aggregate data on adverse events.

CONCLUSION

Nut supplementation had no effect on blood pressure, fasting glucose, or anthropometric profile in the context of atherosclerotic cardiovascular disease.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020163456.

Mitochondrial respiration in white adipose tissue is dependent on body mass index and tissue location in patients undergoing oncological or parietal digestive surgery

Adipose tissue (AT), is a major endocrine organ that plays a key role in health and disease. However, adipose dysfunctions, especially altered energy metabolism, have been under-investigated as white adipocytes have relatively low mitochondrial density. Nevertheless, recent studies suggest that mitochondria could play a major role in AT disorders and that AT mitochondrial activity could depend on adiposity level and location. This clinical study aimed to evaluate mitochondrial respiration and metabolism in human visceral (vAT) and subcutaneous (scAT) AT and their relationship with body mass index (BMI). This clinical study enrolled 67 patients (30 females/37 males) scheduled for digestive surgery without chemotherapy and parietal infection. BMI ranged from 15.4 to 51.9 kg·m-2 and body composition was estimated by computed tomographic images. Mitochondrial respiration was measured in situ in digitonin-permeabilized AT using high-resolution respirometry and a substrate/inhibitor titration approach. Protein levels of mitochondrial and lipid metabolism key elements were evaluated by Western blot. Maximal mitochondrial respiration correlated negatively with BMI (p < .01) and AT area (p < .001) regardless of the anatomical location. However, oxidative phosphorylation respiration was significantly higher in vAT (2.22 ± 0.15 pmol·sec-1·mg-1) than scAT (1.79 ± 0.17 pmol·sec-1·mg-1) (p < 0.001). In line with oxygraphy results, there were higher levels of mitochondrial respiratory chain complexes in low-BMI patients and vAT. Mitochondrial respiration decreased with increasing BMI in both scAT and vAT, without sex-associated difference. Mitochondrial respiration appeared to be higher in vAT than scAT. These differences were both qualitative and quantitative. Clinical Trials Registration IDNCT05417581.

Regulatory effects of statins on CCL2/CCR2 axis in cardiovascular diseases: new insight into pleiotropic effects of statins

BACKGROUND

HMG-CoA reductase inhibitors are well-known medications in the treatment of cardiovascular disorders due to their pleiotropic and lipid-lowering properties. Herein, we reviewed the effects of statins on the CCL2/CCR2 axis.

METHOD

Scopus and Pubmed databases were systematically searched using the following keywords:" Hydroxymethylglutaryl CoA Reductase Inhibitors"," HMG-CoA Reductase Inhibitors"," Statins", "CCL2, Chemokine", "Monocyte Chemoattractant Protein-1" and "Chemokine (C-C Motif) Ligand 2". Evidence investigating the role of statin on MCP-1 in CVD was identified and bibliographies were completely evaluated to gather further related studies.

RESULTS

The anti-inflammatory effects of statins on the CCL2/CCR2 pathway have been widely investigated. Despite inconclusive results, a great body of research supports the regulatory roles of statins on this pathway due to their pleiotropic effects. By disrupting the CCL2/CCR2 axis, statins attenuate the infiltration of monocytes and macrophages into the zone of inflammation and hence down-regulate the inflammatory cascades in various CVDs including atherosclerosis, cardiac remodeling, and stroke, among others.

CONCLUSION

CCL2 plays a major role in the pathogenesis of cardiovascular disorders. Down-regulation of CCL2 is proposed as one of the pleiotropic properties of statins. However, more investigations are required to elucidate which statin in what dose exerts a more potent effect on CCL2/CCR2 pathway.

Effects of mixed nuts as part of a Brazilian Cardioprotective diet on LDL-cholesterol in adult patients after myocardial infarction: a multicenter randomized controlled clinical trial

BACKGROUND

Nuts consumption is related to cardioprotective effects on primary cardiovascular prevention, but studies conducted in secondary prevention are small, scarce and controversial. The objective of this trial was to evaluate the effects of a regional and sustainable cardioprotective diet added or not with an affordable mixed nuts on cardiometabolic features in patients with previous myocardial infarction.

METHODS

DICA-NUTS study is a national, multi-center, and superiority-parallel randomized clinical trial. Males and females over 40 years old diagnosed with previous myocardial infarction in the last 2 to 6 months were included. Patients were allocated into two groups: the Brazilian Cardioprotective diet (DICA Br) supplemented with 30 g/day of mixed nuts (10 g of peanuts; 10 g of cashew; 10 g of Brazil nuts) (intervention group, n = 193); or only DICA Br prescription (control group, n = 195). The primary outcome was low-density lipoprotein cholesterol means (in mg/dL) after 16 weeks. Secondary outcomes were other lipid biomarkers, glycemic and anthropometric data and diet quality.

RESULTS

After adjustment for baseline values, participating study site, time since myocardial infarction and statin treatment regimen (high potency, moderate and low potency/no statins), no significant difference was found between the groups in low-density lipoprotein cholesterol concentrations (intervention-control difference: 3.48 mg/dL [-3.45 to 10.41], P = 0.32). Both groups improved their overall diet quality at the end of the study without differences between them after 16 weeks (intervention-control difference: 1.05 (-0.9 to 2.99); P = 0.29). Other lipids, glycemic profile and anthropometrics were also not different between study groups at the end of the study.

CONCLUSION

Adding 30 g/day of mixed nuts to the DICA Br for 16 weeks did not change lipid, glycemic and anthropometric features in the post-myocardial infarction setting.

TRIAL REGISTRATION

This study is registered on ClinicalTrials.gov website under number NCT03728127 and its World Health Organization Universal Trial Number (WHO-UTN) is U1111-1259-8105.

The Role of Adiponectin and Leptin in Fibro-Calcific Aortic Valve Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Fibro-calcific aortic valve disease (FCAVD) is a progressive disorder characterized by the thickening and calcification of the aortic valve, eventually leading to aortic stenosis. Adiponectin and leptin, known for their anti-inflammatory and proinflammatory properties, respectively, have been implicated in cardiovascular diseases, but their associations with FCAVD are controversial. This meta-analysis aims to evaluate the relationships between adiponectin and leptin levels and FCAVD, particularly in patients with severe aortic stenosis (AS).

METHODS

A systematic search was conducted across the PubMed, Scopus, and Web of Science databases to identify studies on adiponectin and leptin levels in FCAVD. The methodological quality of each study was assessed using the Newcastle-Ottawa Scale. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated, and publication bias was evaluated using Egger's test and funnel plots.

RESULTS

Out of 191 articles identified, 10 studies involving 2360 patients (989 with FCAVD and 1371 controls) were included. The analysis suggested trends in the associations of lower adiponectin levels (SMD = -0.143, 95% CI: -0.344, 0.057, p = 0.161) and higher leptin levels (SMD = 0.175, 95% CI: -0.045, 0.395, p = 0.119) with FCAVD. The association remained a trend for low adiponectin but showed a significant correlation with high leptin in severe AS patients (SMD = 0.29, 95% CI: 0.036, 0.543, p = 0.025).

CONCLUSION

This meta-analysis indicates a potential association between elevated leptin levels and severe aortic stenosis, while the relationship with adiponectin levels remains inconclusive. These findings highlight the need for further and dedicated research to clarify the roles of these adipokines in the pathogenesis of FCAVD and their potential roles as biomarkers for disease progression.

The effects of Garcinia cambogia (hydroxycitric acid) on serum leptin concentrations: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The observed impacts of Garcinia cambogia (GC) on serum leptin indicate inconsistency. We performed a systematic review and meta-analysis on randomized controlled trials (RCTs) to evaluate the effectiveness of GC on leptin levels.

METHODS

A thorough literature search was carried out using different online databases, including Scopus, Web of Science, PubMed, and Google Scholar, until May 25, 2024. Using random effects, weighted mean differences (WMDs) and corresponding 95 % confidence intervals (CIs) were computed. Standard procedures were followed to account for publication bias, study quality, and statistical heterogeneity.

RESULTS

In this meta-analysis, a total of eight eligible trials with 330 participants were ultimately included. Quality assessment showed that half of the included trials were considered to have fair quality, while the other half were deemed to have poor quality. Our analysis, with no indication of publication bias, showed a significantly decreased effect of GC on leptin compared with the placebo (WMD: -5.01 ng/ml; 95 % CI: -9.22 to -0.80, p = 0.02). However, significant heterogeneity was detected between studies (I2 =93.5 %, p < 0.001). The Hartung-Knapp adjustment did not affect our results. Subgroup analysis revealed that GC consumption represents the most effects in trials with sample size ≥ 50 (WMD: -3.63 ng/ml; 95 % CI [-5.51, -1.76], p < 0.001), and mean age of participants ≥ 30 years (WMD: -7.43 ng/ml; 95 % CI [-9.31, -5.56], p < 0.001).

CONCLUSIONS

The findings of the present study showed that leptin levels might decline following GC administration.

REGISTRATION NUMBER

CRD42023486370.

Characterising the genetic architecture of changes in adiposity during adulthood using electronic health records

Obesity is a heritable disease, characterised by excess adiposity that is measured by body mass index (BMI). While over 1,000 genetic loci are associated with BMI, less is known about the genetic contribution to adiposity trajectories over adulthood. We derive adiposity-change phenotypes from 24.5 million primary-care health records in over 740,000 individuals in the UK Biobank, Million Veteran Program USA, and Estonian Biobank, to discover and validate the genetic architecture of adiposity trajectories. Using multiple BMI measurements over time increases power to identify genetic factors affecting baseline BMI by 14%. In the largest reported genome-wide study of adiposity-change in adulthood, we identify novel associations with BMI-change at six independent loci, including rs429358 (APOE missense variant). The SNP-based heritability of BMI-change (1.98%) is 9-fold lower than that of BMI. The modest genetic correlation between BMI-change and BMI (45.2%) indicates that genetic studies of longitudinal trajectories could uncover novel biology of quantitative traits in adulthood.

Relationship between leptin and white blood cells: a potential role in infection susceptibility and severity-the Olivetti Heart Study

A number of evidence showed an emerging role of leptin on immune system, involving inflammation, and innate and adaptive immunity. Few observational studies have evaluated the relationship between leptin and immunity, albeit with low statistical power and methodological differences. Therefore, the aim of this study was to evaluate the potential role of leptin on the immunity, expressed as white blood cells (WBC)-and its subpopulations, by comprehensive multivariate models in a sample of adult men. A cross-sectional evaluation of a general population comprised 939 subjects participating in the Olivetti Heart Study, with available leptin levels and WBC-and its subpopulations. WBC were significantly and positively associated with leptin, C-reactive protein and HOMA index (p < 0.05), but not with age and anthropometric indices (p > 0.05). The multivariate analysis confirmed the association between leptin and WBC, after accounting for main confounders (p < 0.05). Additional analysis on WBC subpopulations showed a positive and significant correlation between leptin and lymphocytes, monocytes and eosinophils (p < 0.05), but not with neutrophils and basophils (p > 0.05). After stratification by body weight, the positive and significant association between leptin and WBC-and its subpopulations-was found in excess body weight participants. The results of this study indicate a direct relationship between leptin levels and WBC-and its subpopulations-in excess body weight participants. These results support the hypothesis that leptin has modulatory functions on immunity and role in the pathophysiology of immune-related diseases, in particular in those associated with excess body weight.

Maternal prenatal cholesterol levels predict offspring weight trajectories during childhood in the Norwegian Mother, Father and Child Cohort Study

BACKGROUND

Numerous intrauterine factors may affect the offspring's growth during childhood. We aimed to explore if maternal and paternal prenatal lipid, apolipoprotein (apo)B and apoA1 levels are associated with offspring weight, length, and body mass index from 6 weeks to eight years of age. This has previously been studied to a limited extent.

METHODS

This parental negative control study is based on the Norwegian Mother, Father and Child Cohort Study and uses data from the Medical Birth Registry of Norway. We included 713 mothers and fathers with or without self-reported hypercholesterolemia and their offspring. Seven parental metabolites were measured by nuclear magnetic resonance spectroscopy, and offspring weight and length were measured at 12 time points. Data were analyzed by linear spline mixed models, and the results are presented as the interaction between parental metabolite levels and offspring spline (age).

RESULTS

Higher maternal total cholesterol (TC) level was associated with a larger increase in offspring body weight up to 8 years of age (0.03 ≤ P_interaction ≤ 0.04). Paternal TC level was not associated with change in offspring body weight (0.17 ≤ P_interaction ≤ 0.25). Higher maternal high-density lipoprotein cholesterol (HDL-C) and apoA1 levels were associated with a lower increase in offspring body weight up to 8 years of age (0.001 ≤ P_interaction ≤ 0.005). Higher paternal HDL-C and apoA1 levels were associated with a lower increase in offspring body weight up to 5 years of age but a larger increase in offspring body weight from 5 to 8 years of age (0.01 ≤ P_interaction ≤ 0.03). Parental metabolites were not associated with change in offspring height or body mass index up to 8 years of age (0.07 ≤ P_interaction ≤ 0.99).

CONCLUSIONS

Maternal compared to paternal TC, HDL-C, and apoA1 levels were more strongly and consistently associated with offspring body weight during childhood, supporting a direct intrauterine effect.

Scytosiphon lomentaria Extract Ameliorates Obesity and Modulates Gut Microbiota in High-Fat-Diet-Fed Mice

Scytosiphon lomentaria (SL) is a brown seaweed with antioxidant and anti-inflammatory properties; however, its effects on obesity are unknown. In this research, we investigated the anti-obesity properties and underlying mechanisms of the SL extract in vitro and in vivo. In 3T3-L1 preadipocytes, SL extract inhibited lipid accumulation, decreased the expression of Acc1, C/ebpa, Pparg mRNA and p-ACC1, and increased the expression of Ucp1 mRNA, UCP1 and p-AMPK. In animal experiments, mice were fed a chow diet, a high-fat diet (HF; 60% of calories as fat), and high-fat diet with SL extract (150 and 300 mg/kg body weight) for eight weeks (n = 10/group). SL extract reduced HF-induced weight gain, epididymal fat weight, fat cell size, LDL-C, leptin, fasting glucose, and glucose tolerance. In addition, SL extract had comparable effects on mRNA expression in WAT and liver to those observed in vitro, thereby inhibiting p-ACC1/ACC1 and increasing p-AMPK/AMPK and UCP1 expression. Furthermore, SL extract decreased HF-induced Firmicutes/Bacteroidetes ratio and reversed HF-reduced Bacteroides spp., Bacteroides vulgatus, and Faecalibacterium prausnitzii. These findings suggest that SL extract can aid in weight loss in mice fed a high-fat diet by altering adipogenic and thermogenic pathways, as well as gut microbiota composition.

From Beneath the Skin to the Airway Wall: Understanding the Pathological Role of Adipose Tissue in Comorbid Asthma-Obesity

This article provides a contemporary report on the role of adipose tissue in respiratory dysfunction. Adipose tissue is distributed throughout the body, accumulating beneath the skin (subcutaneous), around organs (visceral), and importantly in the context of respiratory disease, has recently been shown to accumulate within the airway wall: "airway-associated adipose tissue." Excessive adipose tissue deposition compromises respiratory function and increases the severity of diseases such as asthma. The mechanisms of respiratory impairment are inflammatory, structural, and mechanical in nature, vary depending on the anatomical site of deposition and adipose tissue subtype, and likely contribute to different phenotypes of comorbid asthma-obesity. An understanding of adipose tissue-driven pathophysiology provides an opportunity for diagnostic advancement and patient-specific treatment. As an exemplar, the potential impact of airway-associated adipose tissue is highlighted, and how this may change the management of a patient with asthma who is also obese. © 2023 American Physiological Society. Compr Physiol 13:4321-4353, 2023.

The genetic architecture of changes in adiposity during adulthood

Obesity is a heritable disease, characterised by excess adiposity that is measured by body mass index (BMI). While over 1,000 genetic loci are associated with BMI, less is known about the genetic contribution to adiposity trajectories over adulthood. We derive adiposity-change phenotypes from 1.5 million primary-care health records in over 177,000 individuals in UK Biobank to study the genetic architecture of weight-change. Using multiple BMI measurements over time increases power to identify genetic factors affecting baseline BMI. In the largest reported genome-wide study of adiposity-change in adulthood, we identify novel associations with BMI-change at six independent loci, including rs429358 (a missense variant in APOE). The SNP-based heritability of BMI-change (1.98%) is 9-fold lower than that of BMI, and higher in women than in men. The modest genetic correlation between BMI-change and BMI (45.2%) indicates that genetic studies of longitudinal trajectories could uncover novel biology driving quantitative trait values in adulthood.

Correlation between Medications Used during COVID Infection and Post-conditions after the Acute Phase of Infection: A Cross-sectional Study

Background:

During the COVID-19 pandemic, off-label medication prescribing and utilizing herbal products and multiple vitamins in the treatment, prevention, and symptom management of COVID-19 was an urgently needed practice to halt the SARS-CoV-2 infection crisis and progression.

Objectives:

This study aimed to determine the correlation between medications used during the pandemic and SARS-CoV-2 infection post-recovery symptoms.

Methods:

A cross-sectional questionnaire-based study was conducted on recovered COVID-19 patients. There were 20 multiple-choice questions, including patient demographics, treatment, and post-recovery symptoms. Chi-square and Fisher’s exact tests were used to investigate significant relationships. In addition, Binary logistic regression was performed to determine confounders. Data were analyzed using SPSS version 22.

Results:

Medications and supplements varied in their therapeutic effects on SARS-CoV-2 post-recovery symptoms. Patients who took vitamin D and calcium experienced increased symptom frequency, and patients taking ACE inhibitors experienced more headaches and coughs. Furthermore, patients receiving azithromycin were asymptomatic after recovery. Patients who took H2 antagonists reported persistent headaches and muscle pain.

Conclusion:

Patients infected with SARS-CoV-2 have responded differently to medications, multivitamins, and herbal supplements. Patients reported resolution of some symptoms and persistence of others post-recovery. Therefore, expert opinion should be considered in COVID-19 management until randomized controlled trials answer many questions and determine medications' safety and efficacy in prevention, treatment strategies, and symptoms of SARS-CoV-2 infection post-recovery.

Fenofibrate for COVID-19 and related complications as an approach to improve treatment outcomes: the missed key for Holy Grail

INTRODUCTION

Fenofibrate is an agonist of peroxisome proliferator activated receptor alpha (PPAR-α), that possesses anti-inflammatory, antioxidant, and anti-thrombotic properties. Fenofibrate is effective against a variety of viral infections and different inflammatory disorders. Therefore, the aim of critical review was to overview the potential role of fenofibrate in the pathogenesis of SARS-CoV-2 and related complications.

RESULTS

By destabilizing SARS-CoV-2 spike protein and preventing it from binding angiotensin-converting enzyme 2 (ACE2), a receptor for SARS-CoV-2 entry, fenofibrate can reduce SARS-CoV-2 entry in human cells Fenofibrate also suppresses inflammatory signaling pathways, which decreases SARS-CoV-2 infection-related inflammatory alterations. In conclusion, fenofibrate anti-inflammatory, antioxidant, and antithrombotic capabilities may help to minimize the inflammatory and thrombotic consequences associated with SARSCoV-2 infection. Through attenuating the interaction between SARS-CoV-2 and ACE2, fenofibrate can directly reduce the risk of SARS-CoV-2 infection.

CONCLUSIONS

As a result, fenofibrate could be a potential treatment approach for COVID-19 control.

The potential molecular implications of adiponectin in the evolution of SARS-CoV-2: Inbuilt tendency

Adiponectin (APN) is an adipokine concerned in the regulation of glucose metabolism, insulin sensitivity and fatty acid oxidation. APN plays a critical role in viral infections by regulating the immune response through its anti-inflammatory/pro-inflammatory axis. Reduction of APN may augment the severity of viral infections because APN inhibits immune cells’ response via suppression of inflammatory signaling pathways and stimulation of adenosine monophosphate protein kinase (AMPK). Moreover, APN inhibits the stimulation of nuclear factor kappa B (NF-κB) and regulates the release of pro-inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukins (IL-18, IL-6). In COVID-19, abnormalities of the fatty tissue due to oxidative stress (OS) and hyperinflammation may inhibit the production and release of APN. APN has lung-protective effect and can prevent SARS-CoV-2-induced acute lung injury (ALI) through the amelioration of endoplasmic reticulum (ER) stress, endothelial dysfunction (ED) and stimulation of peroxisome proliferator-activated receptor-alpha (PPAR-α). It has been established that there is a potential correlation between inflammatory signal transduction pathways and APN that contributes to the development of SARS-CoV-2 infections. Deregulation of these molecular pathways affects the expression of APN and vice versa. In addition, the reduction of APN effect in SARS-CoV-2 infection could be a potential cause of the exacerbation of pro-inflammatory effects which are associated with the disease severity. In this context, exploratory, developmental, and extensive prospective studies are necessary.

Roles of Simvastatin and Sildenafil in Modulation of Cranial Irradiation-Induced Bystander Multiple Organs Injury in Rats

In radiobiology and radiation oncology fields, the observation of a phenomenon called radiation-induced bystander effect (RIBE) has introduced the prospect of remotely located tissues' affection. This phenomenon has been broadly developed to involve the concept of RIBE, which are relevant to the radiation-induced response of a distant tissue other than the irradiated one. The current study aimed at investigating each of the RIBE of cranial irradiation on oxidative and inflammatory status in different organs such as liver, kidney, heart, lung, and spleen. Being a vital target of the cholinergic anti-inflammatory response to an inflammatory stimulus, the splenic α-7-nicotinic acetylcholine receptor (α-7nAchR) was evaluated and the hepatic contents of thioredoxin, peroxisome proliferator-activated receptor-alpha and paraoxinase-1 (Trx/PPAR-α/PON) were also assessed as indicators for the liver oxidative stress and inflammatory responses. Being reported to act as antioxidant and anti-inflammatory agents, simvastatin (SV) and/or sildenafil (SD) were investigated for their effects against RIBE on these organs. These objectives were achieved via the biochemical assessments and the histopathological tissues examinations. Five experimental groups, one sham irradiated and four irradiated groups, were exposed to cranial irradiation at dose level of 25 Gy using an experimental irradiator with a Cobalt (Co60) source, RIBE, RIBE + SV (20 mg.(kg.bw)-1 day-1), RIBE + SD (75 mg.(kg.bw)-1 day-1), and RIBE + SV + SD. Cranial irradiation induced structural, biochemical, and functional dys-regulations in non-targeted organs. RIBE-induced organs' injuries have been significantly corrected by the administration of SV and/or SD. Our results suggest the possibility of a potentiated interaction between SV and SD in the modulation of the RIBE associated with head and neck radiotherapy.

Effect of Metformin and Simvastatin in Inhibiting Proadipogenic Transcription Factors

Obesity is a multifactorial chronic disease characterized by the excessive accumulation of fat in adipose tissue driven by hypertrophy and hyperplasia of adipocytes through adipogenesis. Adipogenesis plays a key role in the development of obesity and related metabolic disorders, which makes it potential target for the therapeutic approach to obesity. An increasing number of studies confirm the pleiotropic action of the combined treatment with metformin and statins, suggesting their anti-hypertensive, anti-inflammatory, and anti-adipogenic effect. The aim of this study was to analyze the effect of different doses of metformin (MET) and simvastatin (SIM) on the expression of key transcription factors of adipogenesis. Mouse 3T3-L1 preadipocytes were induced to differentiation in adipogenic medium with sustained MET and SIM treatment to assess the effect on adipogenesis. Nine days after initiating adipogenesis, the cells were prepared for further experiments, including Oil Red O staining, RT-PCR, Western blotting, and immunocytochemistry. Treating the cells with the combination of MET and SIM slightly reduced the intensity of Oil Red O staining compared with the control group, and down-regulated mRNA and protein expression of PPARγ, C/EBPα, and SREBP-1C. In conclusion, the inhibitory effect of MET and SIM on adipocyte differentiation, as indicated by decreased lipid accumulation, appears to be mediated through the down-regulation of adipogenic transcription factors, peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding pro-tein α (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP-1C).

New Insights on the Relationship between Leptin, Ghrelin, and Leptin/Ghrelin Ratio Enforced by Body Mass Index in Obesity and Diabetes

Currently, adipose tissue is considered an endocrine organ, however, there are still many questions regarding the roles of adipokines—leptin and ghrelin being two adipokines. The purpose of the study was to assess the relationship between the adipokines and their ratio with obesity and diabetes. Methods: Sixty patients (mean age 61.88 ± 10.08) were evaluated. Cardiovascular risk factors, leptin, ghrelin, and insulin resistance score values were assessed. The patients were classified according to their body mass index (BMI) as normal weight, overweight, and obese. Results: 20% normal weight, 51.7% overweight, 28.3% obese, and 23.3% diabetic. Obese patients had higher leptin values (in obese 34,360 pg/mL vs. overweight 18,000 pg/mL vs. normal weight 14,350 pg/mL, p = 0.0049) and leptin/ghrelin ratio (1055 ± 641 vs. 771.36 ± 921 vs. 370.7 ± 257, p = 0.0228). Stratifying the analyses according to the presence of obesity and patients’ gender, differences were found for leptin (p = 0.0020 in women, p = 0.0055 in men) and leptin/ghrelin ratio (p = 0.048 in women, p = 0.004 in men). Mean leptin/BMI and leptin/ghrelin/BMI ratios were significantly higher, and the ghrelin/BMI ratio was significantly lower in obese and diabetic patients. In conclusion, obesity and diabetes are associated with changes not only in the total amount but also in the level of adipokines/kg/m². Changes appear even in overweight subjects, offering a basis for early intervention in diabetic and obese patients.

Meteorin-Like Protein (Metrnl) in Obesity, during Weight Loss and in Adipocyte Differentiation

Meteorin-like protein (Metrnl) is an adipo-myokine with pleiotropic effects in adipose tissue (AT). Its systemic regulation in obesity and under weight loss is unclear. Circulating Metrnl concentrations were analyzed by ELISA in severely obese patients undergoing bariatric surgery (BS) or low calorie diet (LCD). Metrnl mRNA expression was analyzed in human and murine tissues and cell lines by quantitative real-time PCR. About 312 morbidly obese individuals underwent BS (n = 181; BMI 53.4 + 6.8 kg/m²) or LCD (n = 131; BMI 43.5 + 6.7 kg/m²). Serum samples were obtained at baseline and 3, 6, and 12 months after intervention. AT specimen from subcutaneous and visceral adipose tissue were resected during BS. Serum Metrnl levels were lower in type 2 diabetic patients and negatively correlated with HbA1c. In BS and LCD patients, Metrnl concentrations significantly increased after 3 months and returned to baseline levels after 12 months. There was no gender-specific effect. Metrnl mRNA expression did not differ between visceral and subcutaneous AT in n = 130 patients. In contrast, Metrnl gene expression in mice was highest in intra-abdominal AT followed by subcutaneous, peri-renal, and brown AT. In the murine 3T3-L1 cell line, Metrnl expression was high in pre-adipocytes and mature adipocytes with a transient downregulation during adipocyte differentiation. Metrnl expression remained unaffected upon treatment with glucose, insulin, fatty acids, bile acids, and incretins. Polyunsaturated omega-3 and omega-6 fatty acids downregulated Metrnl expression. Systemic Metrnl is transiently upregulated during massive weight loss and gene expression in adipocytes is differentially regulated.

The interplay between statins and adipokines. Is this another explanation of statins' 'pleiotropic' effects?

Statin therapy comprises an integral part of secondary and to a lesser extent of primary cardiovascular disease prevention. This is attributed not only to their lipid-lowering properties, but as well to a plethora of pleiotropic actions. Recently, the cytokines secreted by adipose tissue, the so-called adipokines, have been proved to play a critical role in various pathophysiological functions, among which inflammation and atherosclerosis development and vulnerability. The aim of this literature review was to summarize the effects of statins and the underlying mechanisms on the circulating levels of the most common adipokines regulating atherosclerosis process, as a part of their pleiotropic function. Up to now, robust evidence implicates a significant statin-induced reduction of pro-inflammatory adipokines IL-6, TNF-a and visfatin. Weak evidence from limited, small and mostly non-randomized studies suggest increased levels of anti-inflammatory adipokines apelin, vaspin and omentin-1 after statin therapy. In the rest of most known adipokines, statins have shown either controversial (adiponectin, retinol binding protein-4 and fetuin-A) or negligible effects (leptin and resistin) on their circulating levels. Therefore, statins may favourably alter the balance of inflammatory/anti-inflammatory adipokines, implicating a novel atheroprotective mechanism. However, the interplay between statins and adipokines is still not fully elucidated and its potential clinical relevance is warranted.

Serum Levels and Adipose Tissue Gene Expression of Cathelicidin Antimicrobial Peptide (CAMP) in Obesity and During Weight Loss

CAMP (Cathelicidin antimicrobial peptide) is synthesized and secreted by adipocytes and involved in adipose tissue (AT) innate immune response and host defense of subcutaneous AT against Gram positive bacteria. Data on the regulation of CAMP in obesity and during weight loss are scarce and reference values do not exist. Serum CAMP levels (ELISA) and AT gene expression levels (quantitative real time PCR) were investigated in two large and longitudinal (12 months) cohorts of severely obese patients undergoing either a low calorie diet (LCD; n=79) or bariatric surgery (BS; n=156). The impact of metabolic factors on CAMP expression in vitro was investigated in differentiated 3T3-L1 adipocytes. CAMP serum levels significantly increased after BS but not during LCD. Females had lower CAMP serum levels and lower gene expression levels in subcutaneous AT. CAMP was positively correlated to unfavorable metabolic factors/adipokines and negatively to favorable factors/adipokines. CAMP gene expression was higher in subcutaneous than in visceral AT but serum CAMP levels were not correlated to levels of AT gene expression. While certain bile acids upregulated CAMP expression in vitro, high glucose/insulin as well as GLP-1 had an inhibitory effect. There exist gender-specific and AT compartment-specific effects on the regulation of CAMP gene expression. Weight loss induced by BS (but not by LCD) upregulated CAMP serum levels suggesting the involvement of weight loss-independent mechanisms in CAMP regulation such as bile acids, incretins and metabolic factors. CAMP might represent an adipokine at the interface between metabolism and innate immune response.

Regulation of CAMP (cathelicidin antimicrobial peptide) expression in adipocytes by TLR 2 and 4

Recent data argue for a pro-inflammatory role of CAMP (cathelicidin antimicrobial peptide) in adipocytes and adipose tissue (AT) and for regulatory circuits involving TLRs. In order to investigate regulatory effects of TLR2 and TLR4, 3T3-L1 adipocytes were stimulated with TLR2 agonistic lipopeptide MALP-2 and with TLR4 agonist LPS in presence or absence of signal transduction inhibitors. CAMP gene expression was analysed by quantitative real-time PCR in adipocytes and in murine AT compartments and cellular subfractions. CAMP expression was higher in gonadal than in subcutaneous AT and there was a gender-specific effect with higher levels in males. Adipocytes had higher CAMP expression than the stroma-vascular cell (SVC) fraction. MALP-2 up-regulated CAMP expression significantly, mediated by STAT3 and PI3K and potentially (non-significant trend) by NF-κB and MAPK, but not by raf-activated MEK-1/-2. Moreover, LPS proved to act as a potent inducer of CAMP via NF-κB, PI3K and STAT3, whereas specific inhibition of MAPK and MEK-1/-2 had no effect. In conclusion, activation of TLR2 and TLR4 by classical ligands up-regulates adipocyte CAMP expression involving classical signal transduction elements. These might represent future drug targets for pharmacological modulation of CAMP expression in adipocytes, especially in the context of metabolic and infectious diseases.

Adiponectin, Leptin and Cardiovascular Disorders

The landmark discoveries of leptin and adiponectin firmly established adipose tissue as a sophisticated and highly active endocrine organ, opening a new era of investigating adipose-mediated tissue crosstalk. Both obesity-associated hyperleptinemia and hypoadiponectinemia are important biomarkers to predict cardiovascular outcomes, suggesting a crucial role for adiponectin and leptin in obesity-associated cardiovascular disorders. Normal physiological levels of adiponectin and leptin are indeed essential to maintain proper cardiovascular function. Insufficient adiponectin and leptin signaling results in cardiovascular dysfunction. However, a paradox of high levels of both leptin and adiponectin is emerging in the pathogenesis of cardiovascular disorders. Here, we (1) summarize the recent progress in the field of adiponectin and leptin and its association with cardiovascular disorders, (2) further discuss the underlying mechanisms for this new paradox of leptin and adiponectin action, and (3) explore the possible application of partial leptin reduction, in addition to increasing the adiponectin/leptin ratio as a means to prevent or reverse cardiovascular disorders.

Effect of atorvastatin versus rosuvastatin on inflammatory biomarkers and LV function in type 2 diabetic patients with dyslipidemia

BACKGROUND

Statins are potential drugs for decreasing risk of atherosclerotic cardiovascular complications in type 2 diabetic (T2D) patients.

PURPOSE

To examine the efficacy of both rosuvastatin (ROSUVA) and atorvastatin (ATORVA) on LV function and markers of inflammation in T2D patients with dyslipidemia.

METHODS

One hundred-sixty T2D patients were assigned to receive either atorvastatin (ATORVA group, n = 80, 40 mg) or rosuvastatin (ROSUVA group, n = 80, 10 mg), daily for 6 months. Blood was collected for biochemical analysis. The prevalence of left ventricular abnormalities was determined by echocardiography and two-dimensional Speckle-Strain to assess Global Longitudinal Strain (GLS).

RESULTS

ROSUVA vs. ATORVA resulted in significant (p < 0.001) reduction in HbA1c % (9.13 vs 2.35%), LDL-C (22.23% vs. 14.75%), triglycerides (13.56 % vs. 8.21 %), total cholesterol (16.10 % vs. 10.81 %), atherogenic index (18.08. % vs. 10.97%), hs-CRP (23.51 % vs.18.96%), sortilin (33.33 % % vs. 15.08 %), and leptin (31.81 % vs. 23.17 %) but increased adiponectin (97.99 % vs.76.47.1 %) and HDL-C (76.47 % vs. 0.21 %) compared with baseline, respectively. Negative correlations between adiponectin and each of hs-CRP, HbA1c%, total cholesterol, LDL-C, atherogenic index and leptin were found. Also, left ventricular functions were correlated with adiponectin, lipids, HbA1c% and hs-CRP. The areas under receiver operating characteristic curve (AUC) showed that hs-CRP, leptin, sortlin, leptin, and adiponectin were good predictors for cardiovascular events.

CONCLUSION

ROSUVA is more efficacious in improving lipid profile, atherogenic index and modulation of inflammatory biomarkers in dyslipidemic T2D patients compared with ATROVA. However, both statins are equivalent as cardioprotective agents in dyslipidemic T2D patients.

Serum leptin is associated with increased pulse pressure and the development of arterial stiffening in adult men: results of an eight-year follow-up study

High leptin levels are associated with an unfavorable cardiometabolic risk profile. A number of studies found a positive association between leptin and vascular damage, but to date, no observational study has evaluated a potential predictive role of leptin for arterial stiffening. Therefore, the aim of this study was to estimate the role of leptin in the incidence of arterial stiffening (pulse pressure >60 mmHg) and changes in pulse pressure in an 8-year follow-up of a sample of adult men (The Olivetti Heart Study). The analysis included 460 men without baseline arterial stiffening and antihypertensive treatment at baseline and at follow-up (age: 50.0 years, BMI: 26.5 kg/m²). At the end of the follow-up period, the incidence of arterial stiffening was 8%. Baseline leptin was significantly greater in the group that developed arterial stiffening and was significantly correlated with pulse pressure changes over time (p < 0.05). According to the median plasma leptin distribution of the whole population, the sample was stratified into two groups: one with leptin levels above the median and the other with leptin levels below the median. Those who had baseline leptin levels above the median had a greater risk of developing arterial stiffening (odds ratio: 2.5, p < 0.05) and a greater increase in pulse pressure over time (beta: 2.1, p < 0.05), also after adjustment for confounders. The results of this prospective study indicate a predictive role of circulating leptin levels for vascular damage, independent of body weight and blood pressure.

Parathyroid Hormone and 25-Hydroxyvitamin D Do Not Mediate the Association between Dietary Calcium, Protein and Vitamin D Intake and Adiposity and Lipid Profile in Patients with Type 2 Diabetes: a Structural Equation Modeling Approach

This study aimed to utilize structural equation modeling (SEM) techniques to determine the effects of dietary calcium, protein and vitamin D on adiposity and lipidemia and to assess mediatory effects of parathyroid hormone (PTH) and 25-hydroxyvitamin D (25(OH)D) in patients with type 2 diabetes. In this cross-sectional study, a total of 150 diabetic patients (93 females and 57 males) were randomly selected. Anthropometric measures, biochemical analyses, and fat mass percent were recorded. Nutritional data were collected. SEM was performed. Based on the primary hypothesis, adiposity and lipidemia were fitted in a model. The direct effects of dietary calcium (λ = -0.165, p value = 0.002) and PTH (λ = -0.143, p value = 0.011) were significantly associated with lipidemia. There were no significant effects for dietary protein on PTH (λ = -0.270, p value = 0.057), 25(OH)D (λ = -0.071, p value = 0.613), lipidemia (λ = -0.044; p value = 0.638) or adiposity (λ = -0.009, p value = 0.949) as well as for dietary vitamin D on PTH (λ = -0.119, p value = 0.194), 25(OH)D (λ = 0.023, p value = 0.806), lipidemia (λ = 0.034, p value = 0.587) or adiposity (λ = -0.221, p value = 0.118). The correlation between calcium intake and lipidemia, and adiposity are not mediated by 25(OH)D and PTH. There were the direct effects of dietary calcium on adiposity in patients with type 2 diabetes. The model can be tested in future longitudinal and intervention studies to identify the predictors of obesity.

Leptin levels predict the development of left ventricular hypertrophy in a sample of adult men: the Olivetti Heart Study

OBJECTIVE

A higher leptin (LPT) is associated with a greater cardiometabolic risk. Some studies also showed a positive association between LPT and cardiovascular organ damage but no consistent data are available about a predictive role of LPT on cardiac remodelling. Hence, the aim of this study was to evaluate the potential role of LPT on the incidence of left ventricular hypertrophy (LVH) in a sample of adult men.

METHODS

The study population was made up of 439 individuals (age: 51 years) without LVH at baseline, participating in The Olivetti Heart Study. The ECG criteria were adopted to exclude LVH at baseline and echocardiogram criteria for diagnosis of LVH at follow-up were considered.

RESULTS

At baseline, LPT was significantly and positively correlated with BMI, waist circumference, ECG indices, SBP and DBP but not with age and renal function. At the end of the 8-year follow-up period, there was an incidence of 23% in LVH by echocardiography. Individuals who developed LVH had higher baseline age, LPT, BMI, waist circumference, blood pressure and ECG indices (P < 0.05). Furthermore, those that had LPT above the median had greater risk to develop LVH (odds ratio: 1.7; P < 0.05). This association was also confirmed after adjustment for main confounders, among which changes in blood pressure and anthropometric indices.

CONCLUSION

The results of this study suggest a predictive role of circulating LPT levels on cardiac remodelling expressed by echocardiographic LVH, independently of body weight and blood pressure changes over the years.

Circulating leptin is associated with serum uric acid level and its tubular reabsorption in a sample of adult middle-aged men

PURPOSE

Leptin is associated with cardiovascular risk factors (e.g. hypertension, insulin resistance, kidney disease and excess body weight). Experimental studies showed that leptin might affect serum uric acid, by modulation of the uric acid excretion. However, there are few observational data on the relationship between leptin and uric acid in the general population. Therefore, the aim of the present study was to evaluate the relationship between leptin and uric acid and its excretion in a large middle-aged male general population.

METHODS

A sample of 930 adult male individuals (mean age: 52 years) without therapy for high uric acid was included in the analysis (the Olivetti Heart Study).

RESULTS

Uric acid was significantly and positively associated with blood pressure, BMI, waist circumference, insulin resistance, C-reactive protein and leptin (p < 0.01), while inversely with renal function (p = 0.01). The multivariate analysis confirmed the association between leptin and uric acid after adjustment for potential confounders (p < 0.01). After division for adiposity, this trend was confirmed separately for normal weight and excess body weight participants. Moreover, leptin was inversely associated with excretion of uric acid (p < 0.01), also in multivariate analysis (p = 0.03).

CONCLUSION

The results of this study indicate a positive association between circulating leptin levels and uric acid, independently of potential confounders, both in normal and excess body weight men. Furthermore, an inverse association between leptin and uric acid excretion was detected.

Pravastatin alleviates allergic airway inflammation in obesity-related asthma mouse model

Background: Obesity is one of the factors associated with severe, uncontrolled asthma. The effect of pravastatin on asthmatic airway inflammation in obesity has not been evaluated. Methods: C57BL/6 mice were fed a high-fat diet (HFD) to induce obesity with or without ovalbumin (OVA) sensitization and challenge. Pravastatin was administered intraperitoneally during the OVA treatment. Airway inflammation and airway hyper-responsiveness (AHR) were analyzed and lung tissues were examined. The changes in mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/Akt signaling pathways were measured in the lung tissues. Results: HFD with OVA sensitization and challenge exacerbated eosinophilic and neutrophilic airway inflammation and increased AHR compared to lean asthma mice. The levels of cytokines examined in bronchoalveolar lavage fluid (BALF) revealed that the expressions of IL-4, 5, and 17 were elevated in the obese asthmatic group and decreased after pravastatin treatment, indicating that both the Th2 and Th17 pathways were stimulated by HFD-induced obesity and OVA challenge and suppressed by pravastatin treatment. Moreover, the serum leptin and adiponectin ratio was elevated only in obese asthmatic mice and decreased with pravastatin administration. Pravastatin successfully alleviated the airway inflammation of lung tissues and AHR in both obese and lean asthmatic mice, however, treatment with pravastatin had no effects on BALF cell counts and cytokines in lean asthma mice. In lung tissues, the phosphorylation of p38 MAPK was significantly decreased in lean as well as obese asthmatic mice. Conclusions: Pravastatin treatment in obese asthmatic mice suppressed allergic airway infiltration and AHR by inhibition of Th2 and Th17-associated signaling pathways, decreasing the leptin expression and downstream p38 MAPK signaling pathways. The effect on lean asthmatic mice was different, independent of airway cell counts and cytokines.

Evidence of functional bile acid signaling pathways in adipocytes

BACKGROUND AND AIM

Bile acids (BA) are increasingly recognized as pleiotropic and hormone-like signaling molecules with metabolic and endocrine functions. However, the role of BA in white adipocyte physiology remains somewhat obscure. It was the aim to investigate the BA receptors (FXR, TGR5) and FGFR1 (Fibroblast growth factor receptor 1) as well as Bsep (bile salt export pump) in white adipocytes and in murine and human adipose tissue (AT) and to investigate effects of different BA species in adipocyte physiology.

PATIENTS, MATERIAL AND METHODS

Receptor mRNA expression was quantified by real-time PCR in mice, humans and during 3T3-L1 pre-adipocyte differentiation. Adipokines were measured by ELISA upon stimulation by several BA. Effects of BA on TNF- and LPS-induced MCP-1 secretion and lipolysis were analyzed. TNF-induced lipolysis was investigated by glycerol assay.

RESULTS

The present data provide for the first time a detailed expression profile of FXR, TGR5, FGFR1, and Bsep during adipocyte differentiation and in murine and human AT. FGFR1 expression is upregulated in adipose tissue of LPS-injected animals. Several BA regulate secretion of adipokines such as adiponectin and resistin differentially. Importantly, TNF- and LPS-induced MCP-1 release from adipocytes as well as TNF-induced lipolysis can be antagonized by cholic acid (CA) and deoxycholic acid (DCA).

CONCLUSIONS

The present data provide evidence of functional BA signaling pathways in adipocytes and argue for certain MCP-1 related anti-inflammatory effects of BA in TNF- and LPS-induced inflammation, whereas pro-inflammatory resistin is induced by CA and glycocholic acid (GCA). Systemic bile acids might represent a hormonal network regulating white adipocyte physiology including lipolysis.

Statins decrease leptin expression in human white adipocytes

Statin use is associated with increased calorie intake and consequent weight gain. It is speculated that statin‐dependent improvements in lipid profile may undermine the perceived need to follow lipid‐lowering and other dietary recommendations leading consequently to increased calorie intake. However, increases in calorie intake in statin users may also be related to statin‐dependent decreases in satiety factors such as leptin, an adipocyte‐derived adipokine. The objective of our study was to examine the direct effects of statins on leptin expression. Adipocytes are the main source of circulating leptin. Therefore, we examined the effects of atorvastatin and simvastatin on leptin expression in cultured human white adipocytes. We show that treatment of white adipocytes with simvastatin and atorvastatin decreases leptin mRNA expression (simvastatin: P = 0.008, atorvastatin: P = 0.03) and leptin secretion (simvastatin: P = 0.0001, atorvastatin: P = 0.0001). Both simvastatin and atorvastatin mediate decreases in leptin expression via extracellular‐signal‐regulated kinases 1/2 and peroxisome proliferator‐activated receptor gamma pathways (simvastatin: P = 0.01, atorvastatin: P = 0.026). Additionally, statin treatment also induced expected increases in adiponectin, while decreasing monocyte chemoattractant protein 1 (MCP1) mRNA. Furthermore, statins increased secretion of both total as well as high molecular weight adiponectin while decreasing MCP1 secretion. To conclude, statins act directly on human white adipocytes to regulate adipokine secretion and decrease leptin expression. Leptin is an important satiety factor. Hence, statin‐dependent decreases in leptin may contribute, at least in part, to increases in food intake in statin users.

Leptin levels predict the development of insulin resistance in a sample of adult men-The Olivetti Heart Study

BACKGROUND AND AIMS

Leptin (LPT) is associated with unfavourable cardio-metabolic risk profile. Although a number of studies have found a positive association between LPT and insulin resistance (IR), no observational study has evaluated a prospective association to detect a predictive role of LPT in IR. Therefore, the aim of this study was to estimate the role of LPT on the incidence of IR in an 8-year follow-up of a sample of adult men (The Olivetti Heart Study).

METHODS AND RESULTS

The study included 527 not diabetic men without IR (homeostasis model assessment - HOMA index < 2.77 UI) at baseline. Baseline LPT was significantly and positively associated with HOMA index, body mass index (BMI), waist circumference and blood pressure. At the end of the 8-year follow-up period, a positive and significant association was detected between baseline LPT and changes in HOMA index (r = 0.25, p < 0.01) and incidence of IR (OR: 2.6, 95%CI: 1.9-3.4). This trend was also confirmed after adjustment for potential confounders. In addition, the predictive value of LPT was found in subjects who had not experienced any weight increase over the years, and for normal weight and excess body weight participants, separately.

CONCLUSIONS

The results of this prospective study suggest a predictive role of circulating LPT levels on a reduction of insulin sensitivity over time, independently of main potential confounders, in non-diabetic men without IR at baseline. In addition, in normal weight individuals, LPT levels were associated with development of IR.

Functional Implications of HMG-CoA Reductase Inhibition on Glucose Metabolism

HMG-CoA reductase inhibitors, i.e. statins, are effective in reducing cardiovascular disease events but also in cardiac-related and overall mortality. Statins are in general well-tolerated, but currently the concerns are raised if statins may increase the risk of new-onset diabetes mellitus (NOD). In this review, the possible effects of statins on organs/tissues being involved in glucose metabolism, i.e. liver, pancreas, adipose tissue, and muscles, had been discussed. The net outcome seems to be inconsistent and often contradictory, which may be largely affected by in vitro experimental settings or/and in vivo animal conditions. The majority of studies point out statin-induced changes of regulations of isoprenoid metabolites and cell-associated cholesterol contents as predisposing factors related to the statin-induced NOD. On the other hand, it should be considered that dysfunctions of isoprenoid pathway and mitochondrial ATP production and the cholesterol homeostasis are already developed under (pre)diabetic and hypercholesterolemic conditions. In order to connect the basic findings with the clinical manifestation more clearly, further research efforts are needed.