Leptin, An Adipokine With Central Importance in the Global Obesity Problem

Appetite- and Weight-Regulating Neuroendocrine Circuitry in Hypothalamic Obesity

Since hypothalamic obesity (HyOb) was first described over 120 years ago by Joseph Babinski and Alfred Fröhlich, advances in molecular genetic laboratory techniques have allowed us to elucidate various components of the intricate neurocircuitry governing appetite and weight regulation connecting the hypothalamus, pituitary gland, brainstem, adipose tissue, pancreas, and gastrointestinal tract. On a background of an increasing prevalence of population-level common obesity, the number of survivors of congenital (eg, septo-optic dysplasia, Prader-Willi syndrome) and acquired (eg, central nervous system tumors) hypothalamic disorders is increasing, thanks to earlier diagnosis and management as well as better oncological therapies. Although to date the discovery of several appetite-regulating peptides has led to the development of a range of targeted molecular therapies for monogenic obesity syndromes, outside of these disorders these discoveries have not translated into the development of efficacious treatments for other forms of HyOb. This review aims to summarize our current understanding of the neuroendocrine physiology of appetite and weight regulation, and explore our current understanding of the pathophysiology of HyOb.

Impact of Helicobacter pylori and metabolic syndrome on mast cell activation-related pathophysiology and neurodegeneration

Both Helicobacter pylori (H. pylori) infection and metabolic syndrome (MetS) are highly prevalent worldwide. The emergence of relevant research suggesting a pathogenic linkage between H. pylori infection and MetS-related cardio-cerebrovascular diseases and neurodegenerative disorders, particularly through mechanisms involving brain pericyte deficiency, hyperhomocysteinemia, hyperfibrinogenemia, elevated lipoprotein-a, galectin-3 overexpression, atrial fibrillation, and gut dysbiosis, has raised stimulating questions regarding their pathophysiology and its translational implications for clinicians. An additional stimulating aspect refers to H. pylori and MetS-related activation of innate immune cells, mast cells (MC), which is an important, often early, event in systemic inflammatory pathologies and related brain disorders. Synoptically, MC degranulation may play a role in the pathogenesis of H. pylori and MetS-related obesity, adipokine effects, dyslipidemia, diabetes mellitus, insulin resistance, arterial hypertension, vascular dysfunction and arterial stiffness, an early indicator of atherosclerosis associated with cardio-cerebrovascular and neurodegenerative disorders. Meningeal MC can be activated by triggers including stress and toxins resulting in vascular changes and neurodegeneration. Likewise, H.pylori and MetS-related MC activation is linked with: (a) vasculitis and thromboembolic events that increase the risk of cardio-cerebrovascular and neurodegenerative disorders, and (b) gut dysbiosis-associated neurodegeneration, whereas modulation of gut microbiota and MC activation may promote neuroprotection. This narrative review investigates the intricate relationship between H. pylori infection, MetS, MC activation, and their collective impact on pathophysiological processes linked to neurodegeneration. Through a comprehensive search of current literature, we elucidate the mechanisms through which H. pylori and MetS contribute to MC activation, subsequently triggering cascades of inflammatory responses. This highlights the role of MC as key mediators in the pathogenesis of cardio-cerebrovascular and neurodegenerative disorders, emphasizing their involvement in neuroinflammation, vascular dysfunction and, ultimately, neuronal damage. Although further research is warranted, we provide a novel perspective on the pathophysiology and management of brain disorders by exploring potential therapeutic strategies targeting H. pylori eradication, MetS management, and modulation of MC to mitigate neurodegeneration risk while promoting neuroprotection.

Aging adipose tissue, insulin resistance, and type 2 diabetes

With the increase of population aging, the prevalence of type 2 diabetes (T2D) is also rising. Aging affects the tissues and organs of the whole body, which is the result of various physiological and pathological processes. Adipose tissue has a high degree of plasticity and changes with aging. Aging changes the distribution of adipose tissue, affects adipogenesis, browning characteristics, inflammatory status and adipokine secretion, and increases lipotoxicity. These age-dependent changes in adipose tissue are an important cause of insulin resistance and T2D. Understanding adipose tissue changes can help promote healthy aging process. This review summarizes changes in adipose tissue ascribable to aging, with a focus on the role of aging adipose tissue in insulin resistance and T2D.

ITIH5 inhibits proliferation, adipogenic differentiation, and secretion of inflammatory cytokines of human adipose stem cells-A new key in treating obesity?

Inter-α-trypsin inhibitor heavy chain 5 (ITIH5) is widely expressed in the human body, and it is detected to be particularly abundant in adipose tissue. ITIH5 expression is increased in people with obesity compared to lean persons and is decreased by diet-induced weight loss. This suggests that ITIH5 may be involved in the development of adiposity and clinical metabolic variables, although its exact function remains unknown. We measured the protein concentration of ITIH5 in adipose samples from patients undergoing abdominoplasty and tested for correlation with the subjects' BMI as well as inflammatory mediators. We stimulated human adipose stem cells (ASCs) with recombinant (r)ITIH5 protein and tested for an effect on proliferation, differentiation, and immunosuppressive properties when the cells were exposed to an artificial inflammatory environment. We found positive correlations between ITIH5 levels and the BMI (p < .001) as well as concentrations of inflammatory cytokines (TNF-α, IL-6, and MCP-1) in adipose tissue (p < .01). Application of the rITIH5 protein inhibited both proliferation (p < .001) and differentiation of ASCs. Especially, the development of mature adipocytes was reduced by over 50%. Moreover, rITIH5 decreased the release of IL-6 and MCP-1 when the cells were exposed to TNF-α and IL-1β (p < .001). Our data suggest that ITIH5 is an adipokine that is increasingly released during human adipose tissue development, acting as a regulator that inhibits proliferation and adipogenic differentiation of ASCs. ITIH5 thus presents itself as a positive regulator of adipose tissue homeostasis, possibly protecting against both hyperplasia and hypertrophy of adipose tissue and the associated chronic inflammation.

Natural Bioactive Compounds from Marine Invertebrates That Modulate Key Targets Implicated in the Onset of Type 2 Diabetes Mellitus (T2DM) and Its Complications

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an ongoing, risky, and costly health problem that therefore always requires new treatment options. Moreover, although several drugs are available, only 36% of patients achieve glycaemic control, and patient adherence is a major obstacle. With monotherapy, T2DM and its comorbidities/complications often cannot be managed, and the concurrent administration of several hypoglycaemic drugs is required, which increases the risk of side effects. In fact, despite the efficacy of the drugs currently on the market, they generally come with serious side effects. Therefore, scientific research must always be active in the discovery of new therapeutic agents.

DISCUSSION

The present review highlights some of the recent discoveries regarding marine natural products that can modulate the various targets that have been identified as crucial in the establishment of T2DM disease and its complications, with a focus on the compounds isolated from marine invertebrates. The activities of these metabolites are illustrated and discussed.

OBJECTIVES

The paper aims to capture the relevant evidence of the great chemical diversity of marine natural products as a key tool that can advance understanding in the T2DM research field, as well as in antidiabetic drug discovery. The variety of chemical scaffolds highlighted by the natural hits provides not only a source of chemical probes for the study of specific targets involved in the onset of T2DM, but is also a helpful tool for the development of drugs that are capable of acting via novel mechanisms. Thus, it lays the foundation for the design of multiple ligands that can overcome the drawbacks of polypharmacology.

Beneficial Short-Term Effects of Bariatric Surgery on Nutritional Inflammatory Profile and Metabolic Biomarkers

PURPOSE

Bariatric surgery (BS) has several potential metabolic benefits. However, little is known about its impact on changes in the inflammatory potential of diet and its effect on inflammatory and metabolic markers. This study aimed to assess the short-term beneficial effects of BS on dietary inflammatory potential and inflammatory and metabolic markers.

MATERIALS AND METHODS

Participants (n = 20) were evaluated 3 months before and after BS. Body mass, body mass index, anthropometric measurements, fat mass, fat-free mass, visceral fat, skeletal muscle mass, basal metabolic rate, serum lipids, HOMA-IR, QUICKI and inflammatory markers, including leptin, adiponectin, adiponectin/leptin ratio and plasminogen activator inhibitor-1 (PAI-1), were evaluated. Diet data were collected using a 3-day diet record and the dietary inflammatory index (DII®) and energy-adjusted dietary inflammatory index (E-DIITM) scores were computed.

RESULTS

There was a reduction in DII® (2.56 vs 2.13) and E-DIITM (2.18 vs 0.45) indicating an improvement in inflammatory nutritional profile. Moreover, there were increases in the adiponectin/leptin ratio (0.08 vs 0.21) and QUICKI scores (0.31 vs 0.37), and reductions in leptin (36.66 vs 11.41 ng/ml) and HOMA-IR scores (3.93 vs 1.50). There were also improvements in body composition and anthropometric parameters.

CONCLUSIONS

BS promotes changes in metabolic profile, inflammatory state and food intake and these modifications appeared to be associated with improvements in diet-related inflammation, an increase in the adiponectin/leptin ratio and a reduction in leptin. These results contribute to knowledge on the contribution bariatric surgery can make to the treatment of obesity and the reduction of related comorbidities.

A long-term anti-inflammation markedly alleviated high-fat diet-induced obesity by repeated administrations of overexpressing IL10 human umbilical cord-derived mesenchymal stromal cells

Objectives

Obesity is a chronic process and could activate various inflammatory responses, which in turn aggravates obesity and related metabolic syndrome. Here we explored whether long-term inhibition of inflammation could successfully alleviate high-fat diet (HFD)-induced obesity.

Methods

We constructed stable overexpressing interleukin 10 (IL10) human umbilical cord-derived mesenchymal stromal cells (HUCMSCs) which repeatedly were applied to obesity mice with HFD feeding to obtain a long-term anti-inflammation based on the prominent anti-inflammation effects of IL10 and immunomodulatery effects of HUCMSCs. Then we monitored the features of obesity including body weight, serum ALT, AST, and lipids. In addition, glucose homeostasis was determined by glucose tolerance and insulin sensitivity tests. The infiltrated macrophages in adipose tissues and hepatic lipid accumulation were detected, and the expressions of adipogenesis and inflammatory genes in adipose tissues were examined by real-time (RT) PCR and western blot analysis.

Results

Compared with HUCMSCs, IL10-HUCMSCs treatment had much better anti-obesity effects including body weight reduction, less hepatic lipids accumulation, lower amount and size of adipocyte, greater glucose tolerance, less systemic insulin resistance, and less adipose tissue inflammation in HFD feeding mice. Finally, IL10-HUCMSCs could decrease the activation of MAPK JNK of adipose tissue induced by HFD. The inhibition of MAPK JNK signal pathway by a small chemical molecule SP600125 in 3T3-L1 cells, a preadipocyte line, reduced the differentiation of adipocytes and lipid droplet accumulation.

Conclusion

A lasting anti-inflammation based on gene modified stem cell therapy is an effective strategy in preventing diet-induced obesity and obesity-related metabolic syndrome.

The impact of uremic toxins on Alzheimer's disease

Alzheimer's disease (AD) is the most common type of dementia, pathologically characterized by accumulation of senile plaques and neurofibrillary tangles. Chronic kidney disease (CKD) is highly prevalent in elderly population closely associated with occurrence of dementia. Recent epidemiological and experimental studies suggest a potential association of CKD with AD. Both diseases share a panel of identical risk factors, such as type 2 diabetes; and hypertension. However, the relationship between CKD and AD is unclear. Lower clearance of a panel of uremic toxin including cystatin-C, guanidine, and adiponectin due to CKD is implied to contribute to AD pathogenesis. In this review we summarize the current evidence from epidemiological, experimental and clinical studies on the potential contribution of uremic toxins to AD pathogenesis. We describe outstanding questions and propose an outlook on the link between uremic toxins and AD.

Simultaneous exposure to electromagnetic field from mobile phone and unimpeded fructose drinking during pre-, peri-, and post-pubertal stages perturbs the hypothalamic and hepatic regulation of energy homeostasis by early adulthood: experimental evidence

The present-day children-adolescents ubiquitously use the mobile phones and unrestrictedly consume fructose-laden diet. Unfortunately, a rise in the incidence of insulin resistance and fatty liver syndrome in young adults has also been recorded. To delineate a possible correlate, the effect of exposure to electromagnetic field (EMF) from the mobile phone and unrestricted fructose intake during pre-, peri-, and post-pubertal stages of development on orexigenic and anorexigenic signals arising from the hypothalamus and liver of rats is investigated here. The study design included four arms, i.e., "Normal", "Exposure Only (ExpO)", "Fructose Only (FruO)", and "Exposure with Fructose (EF)", wherein weaned rats received either "normal chow and drinking water" or "normal chow and fructose (15%) drinking solution" in presence and absence of EMF exposure (2 h/day) for 8 weeks. The results indicate that the total calories consumed by the EF were higher by early adulthood than normal, possibly under the influence of the raised levels of the orexigenic hormone, i.e., ghrelin, and it reflected as raised rate of weight gain. At early adulthood, the EF recorded mitigated response and sensitivity of insulin. Despite EF being a "fed-state", both centrally and peripherally, the glycolysis was restrained, but the gluconeogenesis was raised. Additionally, the altered lipid profile and the glycogen levels indicate that the EF developed fatty liver. The energy homeostasis of the EF was compromised as evidenced by (a) reduced expression of the glucosensors-GLUT2 and glucokinase in the hypothalamus and liver and (b) reduced expression of the cellular energy regulator-AMPK, orexigenic peptide-NPY, and anorexigenic peptide-POMC in the hypothalamus. Taken together, the present study evidences that the exposure to EMFfrom the mobile phone and unrestricted fructose intake during childhood-adolescence impairs the central and peripheral pathways that mediate the glucosensing, glucoregulation, feeding, and satiety behavior by early adulthood.

The relation between obesity, kisspeptin, leptin, and male fertility

Over the past decades, obesity and infertility in men increased in parallel, and the association between both phenomena have been examined by several researchers. despite the fact that there is no agreement, obesity appears to affect the reproductive potential of men through various mechanisms, such as changes in the hypothalamic-pituitary-testicular (HPT) axis, spermatogenesis, sperm quality and/or alteration of sexual health. Leptin is a hormone produced by the adipose tissue, and its production elevates with increasing body fat. Many studies have supported the relationship between raised leptin production and reproductive function regulation. In fact, Leptin acts on the HPT axis in men at all levels. However, most obese men are insensitive to increased production of endogenous leptin and functional leptin resistance development. Recently, it has been recommended that Kisspeptin neurons mediate the leptin's effects on the reproductive system. Kisspeptin binding to its receptor on gonadotropin-releasing hormone (GnRH) neurons, activates the mammal's reproductive axis and stimulates GnRH release. Increasing infertility associated with obesity is probably mediated by the Kisspeptin-GnRH pathway. In this review, the link between obesity, kisspeptin, leptin, and male fertility will be discussed.

Metformin for Cardiovascular Protection, Inflammatory Bowel Disease, Osteoporosis, Periodontitis, Polycystic Ovarian Syndrome, Neurodegeneration, Cancer, Inflammation and Senescence: What Is Next?

Diabetes is accompanied by several complications. Higher prevalence of cancers, cardiovascular diseases, chronic kidney disease (CKD), obesity, osteoporosis, and neurodegenerative diseases has been reported among patients with diabetes. Metformin is the oldest oral antidiabetic drug and can improve coexisting complications of diabetes. Clinical trials and observational studies uncovered that metformin can remarkably prevent or alleviate cardiovascular diseases, obesity, polycystic ovarian syndrome (PCOS), osteoporosis, cancer, periodontitis, neuronal damage and neurodegenerative diseases, inflammation, inflammatory bowel disease (IBD), tuberculosis, and COVID-19. In addition, metformin has been proposed as an antiaging agent. Numerous mechanisms were shown to be involved in the protective effects of metformin. Metformin activates the LKB1/AMPK pathway to interact with several intracellular signaling pathways and molecular mechanisms. The drug modifies the biologic function of NF-κB, PI3K/AKT/mTOR, SIRT1/PGC-1α, NLRP3, ERK, P38 MAPK, Wnt/β-catenin, Nrf2, JNK, and other major molecules in the intracellular signaling network. It also regulates the expression of noncoding RNAs. Thereby, metformin can regulate metabolism, growth, proliferation, inflammation, tumorigenesis, and senescence. Additionally, metformin modulates immune response, autophagy, mitophagy, endoplasmic reticulum (ER) stress, and apoptosis and exerts epigenetic effects. Furthermore, metformin protects against oxidative stress and genomic instability, preserves telomere length, and prevents stem cell exhaustion. In this review, the protective effects of metformin on each disease will be discussed using the results of recent meta-analyses, clinical trials, and observational studies. Thereafter, it will be meticulously explained how metformin reprograms intracellular signaling pathways and alters molecular and cellular interactions to modify the clinical presentations of several diseases.

Dual Targeting of PTP1B and Aldose Reductase with Marine Drug Phosphoeleganin: A Promising Strategy for Treatment of Type 2 Diabetes

An in-depth study on the inhibitory mechanism on protein tyrosine phosphatase 1B (PTP1B) and aldose reductase (AR) enzymes, including analysis of the insulin signalling pathway, of phosphoeleganin, a marine-derived phosphorylated polyketide, was achieved. Phosphoeleganin was demonstrated to inhibit both enzymes, acting respectively as a pure non-competitive inhibitor of PTP1B and a mixed-type inhibitor of AR. In addition, in silico docking analyses to evaluate the interaction mode of phosphoeleganin with both enzymes were performed. Interestingly, this study showed that phosphoeleganin is the first example of a dual inhibitor polyketide extracted from a marine invertebrate, and it could be used as a versatile scaffold structure for the synthesis of new designed multiple ligands.

Assessment of Acute Pancreatitis Severity and Prognosis with CT-Measured Body Composition

Objective

The aim of this study was to investigate the possible association of muscle and adipose parameters with the severity and prognosis of patients hospitalized with acute pancreatitis (AP).

Methods

A total of 392 hospitalized patients and 309 controls were enrolled in the study analysis from April 1, 2016, to February 1, 2021. The computed tomography scans of each population were evaluated for muscle and adipose parameters. The effects of parameters on developing moderately severe acute pancreatitis (MSAP) or severe acute pancreatitis (SAP) were evaluated using univariate and multivariate logistic regression analyses. Associations with disease recurrence and death were analyzed through Cox regression analysis.

Results

The AP patients had higher levels of visceral adipose tissue (144.25 vs 97.81 cm², p < 0.001) and subcutaneous adipose tissue (135 vs 120 cm², p < 0.001) but lower levels of adipose tissue attenuation (visceral and subcutaneous) and skeletal muscle attenuation (SMA) than the controls (p < 0.05, respectively). Visceral adipose tissue (VAT) and SMA differed significantly with p-values of 0.014 and 0.003 in the different severity groups of AP. In multivariate analysis, VAT and SMA were associated with MSAP or SAP, with odds ratios of 1.003 and 0.973, respectively (95% CI 1.000-1.006, p = 0.041; 95% CI 0.953-0.993, p = 0.010). Cox regression analysis showed that low SMA was strongly associated with an increased mortality in MSAP and SAP patients (HR 10.500, 95% CI 1.344-82.025, p = 0.025). Regression analysis also showed an association of VAT loss of more than 17% with reduced 1-year recurrence of acute pancreatitis (HR 0.427, 95% CI 0.189-0.967, p = 0.041).

Conclusion

VAT and SMA were influential factors for the severity and prognosis of patients with AP. Patients should proper diet and exercise after discharge to reduce VAT and strengthen muscle function to improve prognosis.

High-fat diet and caffeine interact to modulate bone microstructure and biomechanics in mice

AIMS

Although excessive fat and caffeine intake are independent risk factors for bone microstructural and functional disturbances, their association remains overlooked. Thus, we investigated the impact of high-fat diet (HFD) and caffeine alone and combined on serum lipid profile, bone microstructure, micromineral distribution and biomechanical properties.

METHODS

Forty female C57BL/6 mice were randomized into 4 groups daily treated for seventeen weeks with standard diet (SD) or HFD (cafeteria diet) alone or combined with 50 mg/kg caffeine.

KEY FINDINGS

The association between HFD and caffeine reduced the weight gain compared to animals receiving HFD alone. Caffeine alone or combined with HFD increases total and HDL cholesterol circulating levels. HFD also reduced calcium, phosphorus and magnesium bone levels compared to the groups receiving SD, and this reduction was aggravated by caffeine coadministration. From biomechanical assays, HFD combined with caffeine increased bending strength and stiffness of tibia, a finding aligned with the marked microstructural remodeling of the cortical and cancellous bone in animals receiving this combination.

SIGNIFICANCE

Our findings indicated that HFD and caffeine interact to induce metabolic changes and bone microstructural remodeling, which are potentially related to bone biomechanical adaptations in response to HFD and caffeine coadministration.

Maternal waterpipe tobacco smoke exposure during lactation induces hormonal and biochemical changes in rat dams and offspring

Waterpipe smoking is common among pregnant and breastfeeding women. Herein, the effects of waterpipe tobacco smoke (WTS) exposure during lactation on milk composition, hormonal levels and biochemical profile in dams and pups were investigated. Lactating Wistar rats were randomly assigned to receive either WTS (2 hours per day) or fresh air (control group). Milk was collected on day 21 and analysed for protein, lactose and total fat. Blood, from dams and pups, was analysed for insulin, glucose, lipid profile, leptin, prolactin and corticosterone. WTS exposure during lactation increased the blood level of HDL and corticosterone in dams (P < .05). However, the level of milk lactose and blood glucose was reduced in dams after the exposure to WTS during lactation (P < .05). WTS during lactation significantly increased levels of triglycerides, LDL and leptin (P < .05), and a trend of increase in blood level of nicotine and prolactin in pups. Levels of other parameters were not affected by WTS exposure in dams and pups. In conclusion, WTS exposure during lactation altered the milk composition and altered lipid profile, glucose homeostasis and hormonal levels in dams and pups. It is necessary to adopt strategies to enhance tobacco cessation during breastfeeding.

The Mechanisms Involved in Obesity-Induced Male Infertility

BACKGROUND

Obesity resulted by imbalance between the intake of energy and energy consumption can lead to growth and metabolic disease development in people. Both in obese men and animal models, several studies indicate that obesity leads to male infertility.

OBJECTIVE

This review has discussed some mechanisms involved in obesity-induced male infertility.

METHODS

Online documents were searched through Science Direct, Pubmed, Scopus, and Google Scholar websites dating from 1959 to recognize studies on obesity, kisspeptin, leptin, and infertility.

RESULTS

Obesity induced elevated inflammatory cytokines and oxidative stress can affect male reproductive functions, including spermatogenesis disorders, reduced male fertility power and hormones involved in the hypothalamus-pituitary-gonadal axis.

CONCLUSION

There is significant evidence that obesity resulted in male infertility. Obesity has a negative effect on male reproductive function via several mechanisms such as inflammation and oxidative stress.

Depression and Cardiovascular Disease: The Viewpoint of Platelets

Depression is a major cause of morbidity and low quality of life among patients with cardiovascular disease (CVD), and it is now considered as an independent risk factor for major adverse cardiovascular events. Increasing evidence indicates not only that depression worsens the prognosis of cardiac events, but also that a cross-vulnerability between the two conditions occurs. Among the several mechanisms proposed to explain this interplay, platelet activation is the more attractive, seeing platelets as potential mirror of the brain function. In this review, we dissected the mechanisms linking depression and CVD highlighting the critical role of platelet behavior during depression as trigger of cardiovascular complication. In particular, we will discuss the relationship between depression and molecules involved in the CVD (e.g., catecholamines, adipokines, lipids, reactive oxygen species, and chemokines), emphasizing their impact on platelet activation and related mechanisms.

Using proximity extension proteomics assay to discover novel biomarkers associated with circulating leptin levels in patients with type 2 diabetes

We aimed to discover novel associations between leptin and circulating proteins which could link leptin to the development of cardiovascular disease in patients with type 2 diabetes (T2DM). In a discovery phase, we investigated associations between 88 plasma proteins, assessed with a proximity extension assay, and plasma leptin in a cohort of middle-aged patients with T2DM. Associations passing the significance threshold of a False discovery rate of 5% (corresponding to p < 0.0017) were replicated in patients with T2DM in an independent cohort. We also investigated if proteins mediated the longitudinal association between plasma leptin and the incidence of major cardiovascular events (MACE). One protein, adipocyte fatty acid binding protein (A-FABP), was significantly associated with leptin in both the discovery phase [95% CI (0.06, 0.17) p = 0.00002] and the replication cohort [95% CI (0.12, 0.39) p = 0.0003]. Multiplicative interaction analyses in the two cohorts suggest a stronger association between A-FABP and leptin in men than in women. In longitudinal analyses, the association between leptin and MACE was slightly attenuated after adding A-FABP to the multivariate model. Our analysis identified a consistent association between leptin and A-FABP in two independent cohorts of patients with T2DM, particularly in men.Trial registration: ClinicalTrials.gov identifier NCT01049737.

Mealtime: A circadian disruptor and determinant of energy balance?

Circadian rhythms play a critical role in the physiological processes involved in energy metabolism and energy balance (EB). A large array of metabolic processes, including the expression of many energy-regulating endocrine hormones, display temporal rhythms that are driven by both the circadian clock and food intake. Mealtime has been shown to be a compelling zeitgeber in peripheral tissue rhythms. Inconsistent signalling to the periphery, because of mismatched input from the central clock vs time of eating, results in circadian disruption in which central and/or peripheral rhythms are asynchronously time shifted or their amplitudes reduced. A growing body of evidence supports the negative health effects of circadian disruption, with strong evidence in murine models that mealtime-induced circadian disruption results in various metabolic consequences, including energy imbalance and weight gain. Increased weight gain has been reported to occur even without differences in energy intake, indicating an effect of circadian disruption on energy expenditure. However, the translation of these findings to humans is not well established because the ability to undertake rigorously controlled dietary studies that explore the chronic effects on energy regulation is challenging. Establishing the neuroendocrine changes in response to both acute and chronic variations in mealtime, along with observations in populations with routinely abnormal mealtimes, may provide greater insight into underlying mechanisms that influence long-term weight management under different meal patterns. Human studies should explore mechanisms through relevant biomarkers; for example, cortisol, leptin, ghrelin and other energy-regulating neuroendocrine factors. Mistiming between aggregate hormonal signals, or between hormones with their receptors, may cause reduced signalling intensity and hormonal resistance. Understanding how mealtimes may impact on the coordination of endocrine factors is essential for untangling the complex regulation of EB. Here a review is provided on current evidence of the impacts of mealtime on energy metabolism and the underlying neuroendocrine mechanisms, with a specific focus on human research.

Cardioprotective properties of leptin in patients with excessive body mass

Background

Adipose tissue is producing adipokines that play different roles in the pathophysiology of cardiovascular disease.

Aims

The study aimed to assess the role of selected biomarkers in hypertensive patients with overweight and obesity compared with those with normal body-mass index (BMI).

Methods

A total of 62 patients with BMI < 25 kg/m² (median age 54 (46–58) yrs., 57% males) and 51 with BMI ≥ 25 kg/m² (median age 53 (48–59) yrs., 37% males) were enrolled. Biochemical parameters, leptin, adiponectin, and resistin; asymmetric dimethylarginine; interleukin 6; and N-terminal propeptide of type III procollagen, were assessed in plasma. The evaluation of hemodynamic parameters was performed using SphygmoCor 9.0 tonometer. Echocardiography was performed using AlokaAlpha 10 Premier device.

Results

Overweight and obese patients had significantly higher concentration of leptin (34 vs 18 ng/ml; p = 0.03), ADMA (0.43 vs 0.38 μmol/l, p = 0.04), and lower concentration of adiponectin (5.3 vs 7 μg/ml, p = 0.01). The only significant difference in tonometry analysis was higher aortic pulse pressure (mmHg) in patients with BMI ≥ 25 kg/m² group (34 vs 30; p = 0.03). These patients had also significantly lower peak systolic velocity and early diastolic velocity in tissue Doppler imaging of the right ventricle free wall at the level of the tricuspid annulus compared with controls (p = 0.02 and p = 0.001, respectively). The level of leptin is correlated negatively with the left ventricular mass index (LVMI) (R Spearman = − 0.5; p = 0.002) and PWV (R = − 0.4; p = 0.01) and ADMA with total and LDL cholesterol (R = − 0.42; p = 0.008), and adiponectin is correlated positively with HDL cholesterol (R = 0.67; p = 0.0001).

Conclusions

Leptin concentrations were inversely proportional to LVMI and PWV in patients with BMI < 25 kg/m².

Trial registration

Clinicaltrials.gov study ID: NCT04175080.

Cardiometabolic-Based Chronic Disease, Addressing Knowledge and Clinical Practice Gaps: JACC State-of-the-Art Review

In the second part of this JACC State-of-the-Art Review, an early and sustainable preventive care plan is described for cardiometabolic-based chronic disease. This plan can improve cardiometabolic health by targeting early mechanistic events to decrease the risk for certain cardiovascular diseases (e.g., coronary heart disease, heart failure, and atrial fibrillation). Included are various prevention modalities, intensive lifestyle interventions, pharmacotherapy and cardiovascular outcome trial evidence, and bariatric/metabolic procedures. A tactical approach of implementing published clinical practice guidelines/algorithms for early behavioral, adiposity, and dysglycemia targeting is emphasized, as well as relevant educational and research implications.

Nutritional Status as a Mediator of Fatigue and Its Underlying Mechanisms in Older People

Fatigue is an often-neglected symptom but frequently complained of by older people, leading to the inability to continue functioning at a normal level of activity. Fatigue is frequently associated with disease conditions and impacts health status and quality of life. Yet, fatigue cannot generally be completely explained as a consequence of a single disease or pathogenetic mechanism. Indeed, fatigue mirrors the exhaustion of the physiological reserves of an older individual. Despite its clinical relevance, fatigue is typically underestimated by healthcare professionals, mainly because reduced stamina is considered to be an unavoidable corollary of aging. The incomplete knowledge of pathophysiological mechanisms of fatigue and the lack of a gold standard tool for its assessment contribute to the poor appreciation of fatigue in clinical practice. Inadequate nutrition is invoked as one of the mechanisms underlying fatigue. Modifications in food intake and body composition changes seem to influence the perception of fatigue, probably through the mechanisms of inflammation and/or mitochondrial dysfunction. Here, we present an overview on the mechanisms that may mediate fatigue levels in old age, with a special focus on nutrition.

Correlations of serum leptin and leptin resistance with depression and anxiety in patients with type 2 diabetes

AIM

The associations of serum leptin/soluble leptin receptor (sObR) and leptin resistance with symptoms of depression and anxiety were investigated in patients with type 2 diabetes (T2D).

METHODS

We report the results of two cross-sectional studies, performed 2 years apart, that included 216 and 237 T2D patients, respectively. Symptoms of depression and anxiety were assessed with specific questionnaires (Patient Health Questionnaire-9, Center for Epidemiologic Studies Depression Scale, and Generalized Anxiety Disorder-7, respectively). Laboratory data (including leptin and sObR) were collected, and free leptin index (FLI), as an estimate of leptin resistance, was calculated. One hundred forty patients had laboratory data available on both occasions, and were evaluated longitudinally. Simple and multiple correlations between depression/anxiety and parameters of interest were performed.

RESULTS

In both studies, serum leptin levels were higher, whereas resting energy expenditure/leptin ratios were lower in T2D patients with depressive and moderate-severe anxiety symptoms. In the second study, patients with depressive symptoms had higher FLI and lower sObR levels, while those with moderate-severe anxiety only had higher FLI. Depression scores correlated with serum leptin (r = 0.29, [95%CI: 0.14-0.42]; r = 0.32, [95%CI: 0.18-0.45]) and FLI (r = 0.30, [95%CI: 0.15-0.43]; r = 0.32, [95%CI: 0.17-0.45]; P < 0.0001 for all). Multiple regression analyses identified leptin (β = 0.167; t ratio = 1.98) and FLI (β = 2.935, t ratio = 2.44) (P < 0.05 for both) as variables that significantly contributed to depressive symptoms. Depressive symptoms were present in significantly more patients with leptin levels in the highest versus the lowest quartiles on both evaluations (odds ratio: 5.98, 95%CI [1.76-20.32], P < 0.01).

CONCLUSION

Depressive and moderate-severe anxiety symptoms were associated with high leptin concentrations and leptin resistance in T2D patients.

Whey Protein Supplementation Compared to Collagen Increases Blood Nesfatin Concentrations and Decreases Android Fat in Overweight Women: A Randomized Double-Blind Study

Protein supplements are usually used to control body weight, however, the impact of protein quality on body fat attenuation is unknown. We investigated the effects of isocaloric isoproteic supplementation of either whey protein (WG) or hydrolysed collagen supplementation (CG) on dietary intake, adiposity and biochemical markers in overweight women. Methods: In this randomized double-blind study, 37 women, [mean ± SE, age 40.6 ± 1.7 year; BMI (kg/m²) 30.9 ± 0.6], consumed sachets containing 40 g/day of concentrated whey protein (25 g total protein, 2.4 leucine, 1.0 valine, 1.5 isoleucine, n = 17) or 38 g/day of hydrolysed collagen (26 g total protein, 1.02 leucine, 0.91 valine, 0.53 isoleucine, n = 20) in the afternoon snack. The compliance was set at >70% of the total theoretical doses. The dietary intake was evaluated by a 6-day food record questionnaire. At the beginning and after eight weeks of follow-up, body composition was evaluated by using dual-energy X-ray absorptiometry and lipid profile, insulin resistance, C-reactive protein, adiponectin, leptin and nesfastin plasma concentrations were analyzed. Results: Supplements were isocaloric and isoproteic. There were no differences in caloric intake (p = 0.103), protein (p = 0.085), carbohydrate (p = 0.797) and lipids (p = 0.109) intakes. The branched chain amino acids (BCAA) (GC: 1.8 ± 0.1 g vs. WG: 5.5 ± 0.3 g, p < 0.001) and leucine intake (CG: 0.1 ± 0.1 g vs. WG: 2.6 ± 0.1 g, p < 0.001) were higher in WG compared to CG. BMI increased in the CG (0.2 ± 1.1 kg/m², p = 0.044) but did not change in WG. WG decreased the android fat (−0.1 ± 0.3 kg, p = 0.031) and increased nesfatin concentrations (4.9 ± 3.2 ng/mL, p = 0.014) compared to CG. Conclusions: Whey protein supplementation in overweight women increased nesfatin concentrations and could promote increase of resting metabolic rate as part of body composition improvement programs compared to collagen supplementation for 8 weeks. Additionally, our findings suggest that collagen may not be an effective supplement for overweight women who are attempting to alter body composition.

Antioxidant Versus Pro-Apoptotic Effects of Mushroom-Enriched Diets on Mitochondria in Liver Disease

Mitochondria play a central role in non-alcoholic fatty liver disease (NAFLD) progression and in the control of cell death signalling during the progression to hepatocellular carcinoma (HCC). Associated with the metabolic syndrome, NAFLD is mostly driven by insulin-resistant white adipose tissue lipolysis that results in an increased hepatic fatty acid influx and the ectopic accumulation of fat in the liver. Upregulation of beta-oxidation as one compensatory mechanism leads to an increase in mitochondrial tricarboxylic acid cycle flux and ATP generation. The progression of NAFLD is associated with alterations in the mitochondrial molecular composition and respiratory capacity, which increases their vulnerability to different stressors, including calcium and pro-inflammatory molecules, which result in an increased generation of reactive oxygen species (ROS) that, altogether, may ultimately lead to mitochondrial dysfunction. This may activate further pro-inflammatory pathways involved in the progression from steatosis to steatohepatitis (NASH). Mushroom-enriched diets, or the administration of their isolated bioactive compounds, have been shown to display beneficial effects on insulin resistance, hepatic steatosis, oxidative stress, and inflammation by regulating nutrient uptake and lipid metabolism as well as modulating the antioxidant activity of the cell. In addition, the gut microbiota has also been described to be modulated by mushroom bioactive molecules, with implications in reducing liver inflammation during NAFLD progression. Dietary mushroom extracts have been reported to have anti-tumorigenic properties and to induce cell-death via the mitochondrial apoptosis pathway. This calls for particular attention to the potential therapeutic properties of these natural compounds which may push the development of novel pharmacological options to treat NASH and HCC. We here review the diverse effects of mushroom-enriched diets in liver disease, emphasizing those effects that are dependent on mitochondria.

Association of plasma leptin, pro-inflammatory adipokines and cancer-related fatigue in early-stage breast cancer patients: A prospective cohort study

Cancer‐related fatigue (CRF) is subjective and has wide inter‐individual variability. Given that leptin is commonly associated with fatigue syndrome, its use as a potential biomarker for CRF is being investigated. The primary objective of this study was to evaluate the association between leptin and CRF in early‐stage breast cancer patients receiving chemotherapy. In a prospective cohort study, patients completed assessments at baseline (T1), during chemotherapy (T2) and after chemotherapy (T3). Levels of plasma leptin and adipokines were measured using a Luminex bead‐immunoassay and CRF was measured using the Multi‐Dimensional Fatigue Symptom Inventory‐Short Form (MFSI‐SF). Data were analysed longitudinally using a generalised estimating equation incorporating clinically relevant parameters and pro‐inflammatory adipokines. The analysis included 136 patients (mean age ± SD = 51.5 ± 8.8 years; 69.1% receiving anthracycline‐based chemotherapy). More patients experienced CRF at T3 (23.8%) than at T2 (13.8%) compared to baseline. An increase was observed in the median plasma leptin level at T2, followed by a decrease at T3 (T1: 4.07 ng/mL, T2: 4.95 ng/mL and T3: 3.96 ng/mL). In the multivariate model, the change in leptin levels over time was significantly associated with the total MFSI‐SF score (β = −0.15, P = 0.003) after adjusting for the tumour necrosis factor‐α (TNF‐α) level, anxiety, depression, insomnia, age, menopausal status and type of chemotherapy. This is the first study to report leptin as a biomarker that predicts the onset of CRF over time. Future studies are required to validate the findings.

Do Third Molars Contribute to Systemic Inflammation? Results From a Population-Based Study From Northeast Germany

PURPOSE

Erupted and impacted third molars have been reported to contribute to systemic inflammation. This study investigated the systemic effect of third molars on serum levels of inflammatory parameters and on inflammatory messenger peptide hormones in a general population sample.

MATERIALS AND METHODS

Data of 2,151 participants from the Study of Health in Pomerania were included in this study. Erupted or impacted third molars were assessed with whole-body magnetic resonance imaging at 1.5 T and associated with biomarkers of inflammation, lipid metabolism, glucose metabolism, and peptide hormones by linear regression. Models were adjusted for age, gender, smoking status, education, and type 2 diabetes mellitus.

RESULTS

Neither erupted nor impacted third molars were associated with high-sensitivity C-reactive protein, white blood cell count, or fibrinogen as markers for systemic inflammation. Participants with erupted third molars had markedly lower serum levels of leptin (β coefficient, -2.47; 95% confidence interval [CI], -4.47 to -0.48), angiopoietin-2 (β coefficient, -135.1; 95% CI, 248.6 to -21.5), and ratio of angiopoietin-2 to tyrosine kinase with immunoglobulin-like loop epidermal growth factor homology domain 2 (β coefficient, -6.57; 95% CI, -13.06 to -00.7) than participants without third molars. No such associations were observed for impacted third molars.

CONCLUSION

The present results did not substantiate a relation between third molars and an increase in systemic inflammatory markers. Therefore, dental practitioners should be careful when considering this as the only indication for removal of third molars, especially in medically compromised patients. The results of this study showed that participants with erupted third molars had lower levels of messenger peptide hormones, such as leptin and angiopoetin-2.

Are serum leptin levels predicted by lipoproteins, vitamin D and body composition?

BACKGROUND

Both obesity and vitamin D deficiency are important health issues in Pakistan. The connection between body composition, Vitamin D and leptin in young adults is important to be studied as body composition may affect bone health and therefore the possibility of osteoporosis in later life. Few studies have attempted to investigate the effect of body composition and leptin with vitamin D in adolescence.

AIM

To investigate the association of serum leptin with body composition, lipids and 25-hydroxyvitamin D (25OHD) in adults.

METHODS

This cross-sectional study was conducted on 167 apparently healthy adults. Demographics were recorded, bioelectrical impedance analysis was performed and clinical history noted. Serum leptin was measured using DIA source kit on ELISA and total 25OHD was measured on ADVIA-Centaur; Siemens. Total cholesterol and high density lipoprotein cholesterol were quantified using Enzymatic Endpoint Method and Cholesterol Oxidase-Phenol Aminophenazone method respectively. Biochemical analysis was done in the Departments of Pathology and Laboratory Medicine and Biological and Biomedical Sciences, Aga Khan University Hospital Karachi Pakistan.

RESULTS

Median age of the group (n = 167) was 20 years (IQR 27-20); 55.7% were females. Majority (89.2%, n = 149) of the study group was 25OHD deficient, 6% (n = 10) had insufficient serum 25OHD levels and 4.8% (n = 8) had sufficient D levels. Females, had higher median leptin levels [2.71 (IQR 4.76-1.66 ng/mL)] compared to their counterparts [1.3 (3.60-0.54 ng/mL), P < 0.01]. Multiple regression analysis suggested that basal metabolic rate, muscle mass, body fat percent, bone mass and serum 25OHD were the most contributing factors to serum leptin levels. Bone mass and serum 25OHD in fact bore a negative correlation with leptin.

CONCLUSION

The results indicate that basal metabolic rate, muscle mass, body fat percent, bone mass and serum 25OHD have an impact on serum leptin. Being a cross sectional study causal relationship between leptin and other variables could not be determined.

Psoriasis in obesity: comparison of serum levels of leptin and adiponectin in obese subjects - cases and controls

BACKGROUND

Psoriasis and obesity are somewhat related to a low-grade systemic inflammatory response.

OBJECTIVES

To determine leptin and adiponectin levels in psoriasis patients compared to control patients matched for weight.

METHODS

A case-control study was performed, evaluating 113 psoriasis patients and 41 controls with other dermatologic diseases.

RESULTS

The prevalence of obesity was 33% in cases and 21.9% in controls. All evaluated comorbidities were more prevalent among cases. When stratified by weight, the comorbidities were more frequent in overweight patients. We found no correlation between being overweight (p=0.25), leptin (p=0.18) or adiponectin (p=0.762) levels and psoriasis severity. When overweight cases and controls were compared, we found differences in the adiponectin values (p= 0.04). The overweight cases had lower adiponectin levels than the overweight controls. We found no differences in the leptin dosage between cases and controls. The overweight cases had higher leptin values than the normal weight cases (p<0.001).

STUDY LIMITATIONS

Several patients used systemic anti-inflammatory medication.

CONCLUSIONS

The prevalence of obesity among psoriasis cases (33%) was higher than in the general population (17.4%). We did not find any correlation between severity of psoriasis and inflammatory cytokines and the condition of being overweight. The overweight cases had lower values of adiponectin than the overweight controls. It seems, therefore, that there is a relationship between adiponectin and psoriasis, but this relationship depends on the presence of obesity.

Fatty Liver and Autoimmune Hepatitis: Two Forms of Liver Involvement in Lipodystrophies

Introduction

Lipodystrophies are a heterogeneous group of rare diseases (genetic or acquired) characterized by a partial or generalized deficit of adipose tissue, resulting in less energy storage capacity. They are associated with severe endocrine-metabolic complications with significant morbidity and mortality. In the pathogenesis of the acquired forms, immunological disorders may be involved.

Case 1

A 13-year-old female was diagnosed with acquired generalized lipodystrophy and observed for suspicion of portal hypertension. She presented with generalized absence of adipose tissue, cervical and axillary acanthosis nigricans, and massive hepatosplenomegaly. Laboratory tests revealed AST 116 IU/L, ALT 238 IU/L, GGT 114 IU/L, HOMA-IR 28.2, triglycerides 491 mg/L, and leptin < 0.05 ng/mL. Upper gastrointestinal endoscopy saw no signs of portal hypertension. Hepatic histology showed macrovesicular fatty infiltration (60% of hepatocytes) and advanced fibrosis/cirrhosis. Her clinical condition worsened progressively to diabetes requiring treatment with subcutaneous insulin and hepatopulmonary syndrome.

Case 2

A 15-year-old female, diagnosed with acquired partial lipodystrophy, Parkinson syndrome, autoimmune thyroiditis, and autoimmune thrombocytopenia was observed for hypertransaminasemia since the age of 8 years. She had absence of subcutaneous adipose tissue in the upper and lower limbs and ataxia. Laboratory tests showed AST 461 IU/L, ALT 921 IU/L, GGT 145 IU/L, HOMA-IR 32.6, triglycerides 298 mg/dL, normal leptin levels, platelets 84,000/μL, IgG 1,894 mg/dL, positive anti-LKM and anti-LC-1. Hepatic histology was suggestive of autoimmune hepatitis, without steatosis. She progressed favorably under metformin and immunosuppressive treatment.

Conclusion

Early recognition and adequate characterization of liver disease in lipodystrophies is essential for a correct treatment approach. In acquired generalized lipodystrophy, the severe endocrine-metabolic disorder, which leads to steatohepatitis with cirrhotic progression, may benefit from recombinant leptin treatment.

Effects of telmisartan on TNFα induced PPARγ phosphorylation and insulin resistance in adipocytes

BACKGROUND

Telmisartan is an angiotensin II receptor blocker (ARB) and a partial agonist of peroxisome proliferator activated receptor γ (PPARγ). It has been shown to significantly enhance insulin sensitivity in clinical studies and in vitro experiments. However, the effect of telmisartan on PPARγ in adipocytes remains unknown.

METHODS

3T3-L1 adipocytes were incubated with tumor necrosis factor α (TNFα) to simulate growth under an inflammatory condition. On this basis, adipocytes were treated with telmisartan at different concentrations for 1 h. Then, the phosphorylation level of PPARγ, glucose uptake, mRNA levels of PPARγ downstream genes and adiponectin secretion of adipocytes were analyzed.

RESULTS

Telmisartan reduced the phosphorylation level of PPARγ, altered mRNA expressions of adiponectin, adipsin, leptin, FABP4, GLUT4 and CAP, and promoted the secretion of adiponectin. Furthermore, telmisartan treatment restored the decrease of cellular glucose uptake due to TNFα stimulation.

CONCLUSIONS

Telmisartan regulated PPARγ phosphorylation and its downstream gene expressions, promoted glucose uptake and acted as an overall insulin sensitizing agent in adipocytes. The specific phosphorylation site of PPARγ affected by telmisartan, the mechanism of telmisartan in regulating PPARγ phosphorylation, and whether the effects of telmisartan in adipocytes is responsible for its whole-body insulin sensitizing effect require further exploration.

Leptin, cardiovascular diseases and type 2 diabetes mellitus

Leptin, an adipokine that is implicated in the control of food intake via appetite suppression, may also stimulate oxidative stress, inflammation, thrombosis, arterial stiffness, angiogenesis and atherogenesis. These leptin-induced effects may predispose to the development of cardiovascular diseases. In the present review we discuss the evidence linking leptin levels with the presence, severity and/or prognosis of both coronary artery disease and non-cardiac vascular diseases such as stroke, carotid artery disease, peripheral artery disease (PAD) and abdominal aortic aneurysms (AAA) as well as with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). Leptin levels have been positively associated with the presence, severity, extent and lesion complexity of coronary atherosclerosis as well as with the presence, severity and poor clinical outcomes of both ischemic and hemorrhagic strokes. But conflicting results also exist. Furthermore, leptin was reported to independently predict common carotid intima-media thickness and carotid plaque instability. A link between hyperleptinemia and PAD has been reported, whereas limited data were available on the potential association between leptin and AAA. Elevated leptin concentrations have also been related to CKD incidence and progression as well as with insulin resistance, T2DM, micro- and macrovascular diabetic complications. Statins and antidiabetic drugs (including sitagliptin, metformin, pioglitazone, liraglutide and empagliflozin) may affect leptin levels. Further research is needed to establish the potential use (if any) of leptin as a therapeutic target in these diseases.