Can Adipokine FAM19A5 Be a Biomarker of Metabolic Disorders?

Aim: One of the most critical functions of adipose tissue is the production of adipokines, ie, numerous active substances that regulate metabolism. One is the newly discovered FAM19A5, whose older name is TAFA-5. Purpose: The study aimed to review the literature on the FAM19A5 protein. Methods: The review was conducted in December 2023 using the PubMed (Medline) search engine. Sixty-four papers were included in the review. Results: This protein exhibits the characteristics of an adipokine with positive features for maintaining homeostasis. The results showed that FAM19A5 was highly expressed in adipose tissue, with mild to moderate expression in the brain and ovary. FAM19A5 may also inhibit vascular smooth muscle cell proliferation and migration through the perivascular adipose tissue paracrine pathway. Serum levels of FAM19A5 were decreased in obese children compared with healthy controls. There are negative correlations between FAM19A5, body mass index, and fasting insulin. Serum FAM19A5 level is correlated with type 2 diabetes, waist circumference, waist-to-hip ratio, glutamic pyruvic transferase, fasting plasma glucose, HbA1c, and mean shoulder pulse wave velocity. FAM19A5 expression was reduced in mice with obesity. However, the data available needs to be clarified or contradictory. Conclusion: Considering today's knowledge about FAM19A5, we cannot consider this protein as a biomarker of the metabolic syndrome. According to current knowledge, FAM19A5 cannot be considered a marker of metabolic disorders because the results of studies conducted in this area are unclear.

The sex-dependent impact of adipose tissue and inflammation on chronic pain - A cross-sectional study from the all of us research program.

Emerging evidence suggests an association between chronic pain and elevated body fat. We sought to determine if individuals with higher body fat, measured by hip circumference (HC) and waist circumference (WC), are at risk for chronic pain when they demonstrate higher expression of inflammatory markers. We investigated the incidence and severity of pain in patients with varying WC/HC and inflammatory markers (C-Reactive Protein, IL-6, leptin) using the NIH-sponsored All of Us Database. For each inflammatory marker and sex, participants were divided into four groups based on combinations of normal/high marker levels and small/large WC/HC. We used statistical analysis to compare WC/HC and pain severity (mean NRS pain score) between groups of the same sex. In females, but not males, combinations of elevated CRP with large WC/HC exerted additive effects on the incidence of chronic pain (p < 0.01) and severe pain (p < 0.001), as well as on the severity of pain evaluated by the mean NRS pain score (p < 0.01). This relationship held true for females with high IL-6 or leptin and large WC or HC (p < 0.001 for chronic pain and severe pain incidence, and p < 0.05 for pain severity). Neither IL-6 nor leptin showed any significant impact on pain in males. Obesity status and CRP exert additive prognostic effects for chronic pain in females, but not in males. The concomitant evaluation of other inflammatory factors, such as IL-6 or leptin in females, may further augment the prediction of chronic pain. PERSPECTIVE: This article investigates the relationship between chronic pain, obesity, and inflammatory markers. It could help elucidating sex difference in pain mechanisms, as well as the risk factors for chronic pain, potentially improving patient diagnosis, follow-up and treatment.

Gestational Diabetes Mellitus and Colostral Appetite-Regulating Adipokines.

Gestational diabetes mellitus (GDM) is a complex metabolic disorder that has short- and long-term effects on maternal and offspring health. This study aimed to assess the impact of maternal hyperglycemia severity, classified as GDM-G1 (diet treatment) and GDM-G2 (insulin treatment) on colostral appetite-regulating molecules. Colostrum samples were collected from hyperglycemic (N = 30) and normoglycemic (N = 21) mothers, and the concentrations of milk hormones were determined by immunoenzymatic assay. A difference was found for milk ghrelin, but not for molecules such as adiponectin, leptin, resistin, or IGF-I levels, in relation to maternal hyperglycemia. The colostral ghrelin in the GDM-G1 cohort (0.21 ng/mL) was significantly lower than for GDM-G2 (0.38 ng/mL) and non-GDM groups (0.36 ng/mL). However, colostral resistin was higher, but not significantly, for GDM-G1 (13.33 ng/mL) and GDM-G2 (12.81 ng/mL) cohorts than for normoglycemic mothers (7.89 ng/mL). The lack of difference in relation to hyperglycemia for milk leptin, adiponectin, leptin-adiponectin ratio, resistin, and IGF-I levels might be the outcome of effective treatment of GDM during pregnancy. The shift between ghrelin and other appetite-regulating hormones might translate into altered ability to regulate energy balance, affecting offspring's metabolic homeostasis.

A Narrative Review on Adipose Tissue and Overtraining: Shedding Light on the Interplay among Adipokines, Exercise and Overtraining.

Lifestyle factors, particularly physical inactivity, are closely linked to the onset of numerous metabolic diseases. Adipose tissue (AT) has been extensively studied for various metabolic diseases such as obesity, type 2 diabetes, and immune system dysregulation due to its role in energy metabolism and regulation of inflammation. Physical activity is increasingly recognized as a powerful non-pharmacological tool for the treatment of various disorders, as it helps to improve metabolic, immune, and inflammatory functions. However, chronic excessive training has been associated with increased inflammatory markers and oxidative stress, so much so that excessive training overload, combined with inadequate recovery, can lead to the development of overtraining syndrome (OTS). OTS negatively impacts an athlete's performance capabilities and significantly affects both physical health and mental well-being. However, diagnosing OTS remains challenging as the contributing factors, signs/symptoms, and underlying maladaptive mechanisms are individualized, sport-specific, and unclear. Therefore, identifying potential biomarkers that could assist in preventing and/or diagnosing OTS is an important objective. In this review, we focus on the possibility that the endocrine functions of AT may have significant implications in the etiopathogenesis of OTS. During physical exercise, AT responds dynamically, undergoing remodeling of endocrine functions that influence the production of adipokines involved in regulating major energy and inflammatory processes. In this scenario, we will discuss exercise about its effects on AT activity and metabolism and its relevance to the prevention and/or development of OTS. Furthermore, we will highlight adipokines as potential markers for diagnosing OTS.

Biomarkers in Systemic Lupus Erythematosus along with Metabolic Syndrome.

Metabolic syndrome (MetS) is a group of physiological abnormalities characterized by obesity, insulin resistance (IR), and hypertriglyceridemia, which carry the risk of developing cardiovascular disease (CVD) and type 2 diabetes (T2D). Immune and metabolic alterations have been observed in MetS and are associated with autoimmune development. Systemic lupus erythematosus (SLE) is an autoimmune disease caused by a complex interaction of environmental, hormonal, and genetic factors and hyperactivation of immune cells. Patients with SLE have a high prevalence of MetS, in which elevated CVD is observed. Among the efforts of multidisciplinary healthcare teams to make an early diagnosis, a wide variety of factors have been considered and associated with the generation of biomarkers. This review aimed to elucidate some primary biomarkers and propose a set of assessments to improve the projection of the diagnosis and evolution of patients. These biomarkers include metabolic profiles, cytokines, cardiovascular tests, and microRNAs (miRs), which have been observed to be dysregulated in these patients and associated with outcomes.

Obesity and Inflammatory Factors in the Progression of Early-Onset Colorectal Cancer.

Metabolic dysfunction associated with obesity leads to a chronic pro-inflammatory state with systemic effects, including the alteration of macrophage metabolism. Tumor-associated macrophages have been linked to the formation of cancer through the production of metabolites such as itaconate. Itaconate downregulates peroxisome proliferator-activated receptor gamma as a tumor-suppressing factor and upregulates anti-inflammatory cytokines in M2-like macrophages. Similarly, leptin and adiponectin also influence macrophage cytokine expression and contribute to the progression of colorectal cancer via changes in gene expression within the PI3K/AKT pathway. This pathway influences cell proliferation, differentiation, and tumorigenesis. This work provides a review of obesity-related hormones and inflammatory mechanisms leading to the development and progression of early-onset colorectal cancer (EOCRC). A literature search was performed using the PubMed and Cochrane databases to identify studies related to obesity and EOCRC, with keywords including 'EOCRC', 'obesity', 'obesity-related hormones', 'itaconate', 'adiponectin', 'leptin', 'M2a macrophage', and 'microbiome'. With this concept of pro-inflammatory markers contributing to EOCRC, increased use of chemo-preventative agents such as aspirin may have a protective effect. Elucidating this association between obesity-related, hormone/cytokine-driven inflammatory effects with EOCRC may help lead to new therapeutic targets in preventing and treating EOCRC.

Bone marrow adipocytes and lung cancer bone metastasis: unraveling the role of adipokines in the tumor microenvironment.

Bone is a common site of metastasis for lung cancer. The "seed and soil" hypothesis suggests that the bone marrow microenvironment ("soil") may provide a conducive survival environment for metastasizing tumor cells ("seeds"). The bone marrow microenvironment, comprising a complex array of cells, includes bone marrow adipocytes (BMAs), which constitute about 70% of the adult bone marrow volume and may play a significant role in tumor bone metastasis. BMAs can directly provide energy for tumor cells, promoting their proliferation and migration. Furthermore, BMAs participate in the tumor microenvironment's osteogenesis regulation, osteoclast(OC) regulation, and immune response through the secretion of adipokines, cytokines, and inflammatory factors. However, the precise mechanisms of BMAs in lung cancer bone metastasis remain largely unclear. This review primarily explores the role of BMAs and their secreted adipokines (leptin, adiponectin, Nesfatin-1, Resistin, chemerin, visfatin) in lung cancer bone metastasis, aiming to provide new insights into the mechanisms and clinical treatment of lung cancer bone metastasis.

Understanding wound healing in obesity.

Obesity has become more prevalent in the global population. It is associated with the development of several diseases including diabetes mellitus, coronary heart disease, and metabolic syndrome. There are a multitude of factors impacted by obesity that may contribute to poor wound healing outcomes. With millions worldwide classified as obese, it is imperative to understand wound healing in these patients. Despite advances in the understanding of wound healing in both healthy and diabetic populations, much is unknown about wound healing in obese patients. This review examines the impact of obesity on wound healing and several animal models that may be used to broaden our understanding in this area. As a growing portion of the population identifies as obese, understanding the underlying mechanisms and how to overcome poor wound healing is of the utmost importance.

Characterization of circulating leptin-receptor levels following acute sleep restriction: A pilot study on healthy adult females.

BACKGROUND: Insufficient sleep adversely affects energy homeostasis by decreasing leptin levels. The underlying physiological mechanisms; however, remain unclear. Circulating leptin is well described to be regulated by its soluble receptor (sOB-R). Intriguingly, the impact of short sleep duration on sOB-R levels has never been characterized. AIM: In this study, we investigated, for the first time, the variation of sOB-R levels and its temporal relationship with circulating leptin upon acute sleep restriction. METHODS: Five adult females were maintained on an 8-hour sleep schedule (bedtime at 00:00) for 1 week before restricting their sleep to 4.5 h (bedtime at 03:30) on 2 consecutive nights. Balanced meals were scheduled to specific hours and sleep was objectively measured. Four-hour blood samples were regularly collected during waking hours between 08:00 and 00:00. RESULTS: Sleep restriction resulted in lower leptin (20.9 ± 1.7 vs 25.7 ± 1.7 ng/ml) and higher sOB-R concentrations (24.4 ± 1.2 vs 19.8 ± 1.6 ng/ml). Neither the discordant temporal relationship nor the pattern of leptin and sOB-R were altered in response to sleep restriction. CONCLUSION: Our results suggest that sleep restriction may modulate circulating leptin levels and possibly metabolism via upregulating its soluble receptor. This observation may have valuable therapeutic implications when considering sOB-R as a potential target during the management of metabolic disturbances.

Molecular and pathophysiological relationship between obesity and chronic inflammation in the manifestation of metabolic dysfunctions and their inflammation­mediating treatment options (Review).

Obesity reaches up to epidemic proportions globally and increases the risk for a wide spectrum of co­morbidities, including type­2 diabetes mellitus (T2DM), hypertension, dyslipidemia, cardiovascular diseases, non­alcoholic fatty liver disease, kidney diseases, respiratory disorders, sleep apnea, musculoskeletal disorders and osteoarthritis, subfertility, psychosocial problems and certain types of cancers. The underlying inflammatory mechanisms interconnecting obesity with metabolic dysfunction are not completely understood. Increased adiposity promotes pro­inflammatory polarization of macrophages toward the M1 phenotype, in adipose tissue (AT), with subsequent increased production of pro­inflammatory cytokines and adipokines, inducing therefore an overall, systemic, low­grade inflammation, which contributes to metabolic syndrome (MetS), insulin resistance (IR) and T2DM. Targeting inflammatory mediators could be alternative therapies to treat obesity, but their safety and efficacy remains to be studied further and confirmed in future clinical trials. The present review highlights the molecular and pathophysiological mechanisms by which the chronic low­grade inflammation in AT and the production of reactive oxygen species lead to MetS, IR and T2DM. In addition, focus is given on the role of anti­inflammatory agents, in the resolution of chronic inflammation, through the blockade of chemotactic factors, such as monocytes chemotractant protein­1, and/or the blockade of pro­inflammatory mediators, such as IL­1ß, TNF­α, visfatin, and plasminogen activator inhibitor­1, and/or the increased synthesis of adipokines, such as adiponectin and apelin, in obesity­associated metabolic dysfunction.

Biological markers of adipose tissue: Adipokines.

We currently have a large sum of clinical and experimental data documenting the involvement of numerous adipokines in the maintenance of energy homeostasis in healthy individuals and their dysregulation in diseases such as obesity, metabolic syndrome or type 2 diabetes. Despite the impressive discoveries made in this field over many years, much remains to be done before understanding all the physiological and pathological implications, and hoping for the development of other effective and safe therapeutic strategies. Two original adipokines will be taken as examples to illustrate these remarks, chemerin and neuregulin 4.

Increased serum adipokines are associated with sarcopenia in non-obese women with rheumatoid arthritis.

Large cohort studies have disclosed the association between obesity and rheumatoid arthritis (RA) risk. The sarcopenia prevalence in RA patients can be up to 31%. However, there is little information linking adipokines to sarcopenia in RA, so this study aimed to investigate whether adipokines were indeed involved in secondary sarcopenia in RA with a focus on non-obese females. Sixty-four female patients and 36 controls were included in this study. The serum adipokine levels (leptin and adiponectin) were determined by ELISA kits. The impacts of adipokines on muscle atrophy and potential autophagy were examined in mouse myoblasts, C2C12, upon treatment with recombinant leptin and adiponectin agonist (AdipoRan). Interestingly, serum adiponectin was significantly increased but the ratio of leptin/adiponectin was dramatically decreased in the RA patients with sarcopenia. After normalization by body mass, serum leptin was positively associated but adiponectin was negatively associated with muscle mass respectively, even after adjustment for fat mass. Treating C2C12 cells with leptin and AdipoRan inhibited proliferation of mature myotube respectively, as did treatment with the serum from RA patients. A combination of low leptin and high AdipoRan greatly decreased myogenin, but instead increased MAFbx and MuRF-1 as well as increased Beclin 1, Atg5, and LC3ß. Taken together, our study reveals that secondary sarcopenia of RA females may be an imbalance of RA-related, but not obesity-related, increase in adipokine production; additionally, the reduced leptin/adiponectin ratio could be a better indicator in monitoring sarcopenia in non-obese RA females. Moreover, adipokine imbalance may promote muscle atrophy through inducing autophagy.

Importance of circulating leptin and adiponectin in the causal pathways between obesity and the development of colorectal cancer in Japanese men.

BACKGROUND: The mechanistic associations between obesity and risk of colorectal cancer (CRC) remain unclear. Here, using body mass index (BMI) as an obesity indicator, we decomposed the total effects of obesity on the risk of CRC into: (1) direct effects, which are possibly mediated by unmeasured or currently unknown factors; (2) indirect effects mediated by circulating leptin and adiponectin; and (3) indirect effects that are not mediated by circulating leptin and adiponectin but by hyperinsulinemia and chronic inflammation (assessed via circulating connecting peptide and C-reactive protein, respectively). METHODS: We adopted a causal mediation framework, using data from a large prospective cohort study of 44,271 Japanese men. RESULTS: BMI was not associated with the risk of CRC due to direct and indirect effects that were not mediated by circulating leptin and adiponectin. By contrast, individuals with BMIs of 25.0-27.4 kg/m2 (risk ratio, 1.29; 95% confidence interval, 0.98-1.69) and ≥27.5 kg/m2 (risk ratio, 1.28; 95% confidence interval, 0.98-1.68) had a higher risk of CRC due to indirect effects of circulating leptin and adiponectin. CONCLUSIONS: Our mediation analyses suggest that the association between BMI and CRC risk may be largely mediated by a pathway involving circulating leptin and adiponectin.

White adipose tissue, a novel antirheumatic target: Clues from its secretory capability and adipectomy-based therapy.

BACKGROUND AND PURPOSE: White adipose tissue (WAT) is involved in rheumatoid arthritis (RA). This study explored its potential as an antirheumatic target. EXPERIMENTAL APPROACH: WAT status of healthy and adjuvant-induced arthritis (AIA) rats were compared. The contribution of WAT to RA pathology was evaluated by pre-adipocyte transplant experiments and by dissecting perirenal fat pads of AIA rats. The impact of RA on WAT was investigated by culturing pre-adipocytes. Proteins differentially expressed in WAT of healthy and AIA rats were identified by the UPLC/MS2 method. These together with PPARγ siRNA and agonist were used to treat pre-adipocytes in vitro. The medium was used for THP-1 monocyte culture. KEY RESULTS: Compared with healthy controls, AIA WAT was smaller but secreted more leptin, eNAMPT, MCP-1, TNF-α, and IL-6. AIA rat pre-adipocytes increased the levels of these adipokines in healthy recipients. RA patients' serum induced a similar secretion change and impaired differentiation of pre-adipocytes. Adipectomy eased AIA-related immune abnormalities and arthritic manifestations. Hepatokines PON1, IGFBP4, and GPIHBP1 were among the differential proteins in high levels in RA blood, and induced inflammatory secretions by pre-adipocytes. GPIHBP1 inhibited PPARγ expression and caused differentiation impairment and inflammatory secretion by pre-adipocytes, a similar outcome to PPARγ-silencing. This endowed the cells with an ability to activate monocytes, which can be abrogated by rosiglitazone. CONCLUSION AND IMPLICATIONS: Certain hepatokines potentiate inflammatory secretions by pre-adipocytes and expedite RA progression by inhibiting PPARγ. Targeting this signalling or abnormal WAT secretion by various approaches may reduce RA severity.

The role of adipokines in osteoporosis management: a mini review.

The prevalence of osteoporosis has been on the rise globally. With ageing populations, research has sought therapeutic solutions in novel areas. One such area is that of the adipokines. Current literature points to an important role for these chemical mediators in relation to bone metabolism. Well-established adipokines have been broadly reported upon. These include adiponectin and leptin. However, other novel adipokines such as visfatin, nesfatin-1, meteorin-like protein (Metrnl), apelin and lipocalin-2 are starting to be addressed pre-clinically and clinically. Adipokines hold pro-inflammatory and anti-inflammatory properties that influence the pathophysiology of various bone diseases. Omentin-1 and vaspin, two novel adipokines, share cardioprotective effects and play essential roles in bone metabolism. Studies have reported bone-protective effects of omentin-1, whilst others report negative associations between omentin-1 and bone mineral density. Lipocalin-2 is linked to poor bone microarchitecture in mice and is even suggested to mediate osteoporosis development from prolonged disuse. Nesfatin-1, an anorexigenic adipokine, has been known to preserve bone density. Animal studies have demonstrated that nesfatin-1 treatment limits bone loss and increases bone strength, suggesting exogenous use as a potential treatment for osteopenic disorders. Pre-clinical studies have shown adipokine apelin to have a role in bone metabolism, mediated by the enhancement of osteoblast genesis and the inhibition of programmed cell death. Although many investigations have reported conflicting findings, sufficient literature supports the notion that adipokines have a significant influence on the metabolism of bone. This review aims at highlighting the role of novel adipokines in osteoporosis while also discussing their potential for treating osteoporosis.

Maternal Blood Adipokines and Their Association with Fetal Growth: A Meta-Analysis of the Current Literature.

Background: Assessing fetal growth constitutes a fundamental aim within the realm of prenatal care. Impaired prenatal growth increases the risk of perinatal mortality, morbidity, and poor newborn outcomes. Growth restriction increases the risk of premature birth problems, as well as the risk of poor neurodevelopmental outcomes and future non-communicable disorders such as hypertension and metabolic syndrome as adults. The objective of this systematic review is to accumulate current literature evidence to assess the patterns of serum adipokine levels among women with growth-restricted fetuses and assess their potential alterations in those high-risk pregnancies. Methods: Medline, Scopus, CENTRAL, Clinicaltrials.gov, and Google Scholar databases were systematically searched from inception until 31 March 2023. All observational studies reporting serum adipokine values among women with appropriately grown and growth-restricted fetuses were held eligible. Results: The current systematic review encompassed a total of 20 studies, incorporating a patient population of 1850 individuals. Maternal blood leptin emerged as the adipokine most investigated, as evidenced by 13 studies encompassing a collective sample size of 1081 patients, all of which explored its potential correlation with intrauterine growth restriction. Elevated levels of leptin were detected in fetuses with intrauterine growth restriction, although the observed difference did not reach statistical significance. Furthermore, regarding adiponectin, the meta-analysis conducted indicated that there were not any statistically significant differences observed in the mean values of adiponectin. The available data on the remaining three adipokines were extremely limited, making it difficult for any solid conclusions to be extracted. Conclusions: Though limited and inconsistent, the existing data suggest that fetal growth restriction is not linked to leptin, adiponectin, visfatin, resistin, or RBP4. More substantial prospective studies are needed to comprehend the importance of established and novel adipokines.

Plasma adiponectin/leptin ratio associates with subcutaneous abdominal and omental adipose tissue characteristics in women.

BACKGROUND: A better understanding of adipose tissue (AT) dysfunction, which includes morphological and functional changes such as adipocyte hypertrophy as well as impaired adipogenesis, lipid storage/mobilization, endocrine and inflammatory responses, is needed in the context of obesity. One dimension of AT dysfunction, secretory adiposopathy, often assessed as a low plasma adiponectin (A)/leptin (L) ratio, is commonly observed in obesity. The aim of this study was to examine markers of AT development and metabolism in 67 women of varying age and adiposity (age: 40-62 years; body mass index, BMI: 17-41 kg/m2) according to levels of adiponectinemia, leptinemia or the plasma A/L ratio. METHODS: Body composition, regional AT distribution and circulating adipokines were determined. Lipolysis was measured from glycerol release in subcutaneous abdominal (SCABD) and omental (OME) adipocytes under basal, isoproterenol-, forskolin (FSK)- and dibutyryl-cyclic AMP (DcAMP)-stimulated conditions. Adipogenesis (C/EBP-α/ß/δ, PPAR-γ2 and SREBP-1c) and lipid metabolism (ß2-ARs, HSL, FABP4, LPL and GLUT4) gene expression (RT-qPCR) was assessed in both fat depots. Participants in the upper versus lower tertile of adiponectin, leptin or the A/L ratio were compared. RESULTS: Basal lipolysis was similar between groups. Women with a low plasma A/L ratio were characterized by higher adiposity and larger SCABD and OME adipocytes (p<0.01) compared to those with a high ratio. In OME adipocytes, women in the low adiponectinemia tertile showed higher isoproterenol-stimulated lipolysis (0.01

Omentin associates with serum metabolite profiles indicating lower diabetes risk: KORA F4 Study.

INTRODUCTION: Circulating omentin levels have been positively associated with insulin sensitivity. Although a role for adiponectin in this relationship has been suggested, underlying mechanisms remain elusive. In order to reveal the relationship between omentin and systemic metabolism, this study aimed to investigate associations of serum concentrations of omentin and metabolites. RESEARCH DESIGN AND METHODS: This study is based on 1124 participants aged 61-82 years from the population-based KORA (Cooperative Health Research in the Region of Augsburg) F4 Study, for whom both serum omentin levels and metabolite concentration profiles were available. Associations were assessed with five multivariable regression models, which were stepwise adjusted for multiple potential confounders, including age, sex, body mass index, waist-to-hip ratio, lifestyle markers (physical activity, smoking behavior and alcohol consumption), serum adiponectin levels, high-density lipoprotein cholesterol, use of lipid-lowering or anti-inflammatory medication, history of myocardial infarction and stroke, homeostasis model assessment 2 of insulin resistance, diabetes status, and use of oral glucose-lowering medication and insulin. RESULTS: Omentin levels significantly associated with multiple metabolites including amino acids, acylcarnitines, and lipids (eg, sphingomyelins and phosphatidylcholines (PCs)). Positive associations for several PCs, such as diacyl (PC aa C32:1) and alkyl-alkyl (PC ae C32:2), were significant in models 1-4, whereas those with hydroxytetradecenoylcarnitine (C14:1-OH) were significant in all five models. Omentin concentrations were negatively associated with several metabolite ratios, such as the valine-to-PC ae C32:2 and the serine-to-PC ae C32:2 ratios in most models. CONCLUSIONS: Our results suggest that omentin may influence insulin sensitivity and diabetes risk by changing systemic lipid metabolism, but further mechanistic studies investigating effects of omentin on metabolism of insulin-sensitive tissues are needed.

Exercise Alleviates Aging of Adipose Tissue through Adipokine Regulation.

Adipose tissue undergoes changes with aging, leading to increased adiposity, inflammatory cell infiltration, reduced angiogenesis, heightened oxidative stress, and alterations in its metabolic function. Regular exercise has been recognized as a powerful intervention that can positively influence adipose tissue health and mitigate the effects of aging. However, the molecular mechanisms underlying the benefits of regular exercise on aging adipose tissue function remain poorly understood. Adipokines released through regular exercise play a potential role in mitigating adipose tissue aging, enhancing the metabolism of glucose and lipids, reducing inflammation and fibrosis, and promoting fat browning and thermogenesis. This review comprehensively summarizes the benefits of regular exercise in addressing the age-related decline in adipose tissue function. Utilizing relevant examples of this approach, we address the possibility of designing therapeutic interventions based on these molecular mechanisms.

The role of novel adipokines and adipose-derived extracellular vesicles (ADEVs): Connections and interactions in liver diseases.

Adipose tissues (AT) are an important endocrine organ that secretes various functional adipokines, peptides, non-coding RNAs, and acts on AT themselves or other distant tissues or organs through autocrine, paracrine, or endocrine manners. An accumulating body of evidence has suggested that many adipokines play an important role in liver metabolism. Besides the traditional adipokines such as adiponectin and leptin, many novel adipokines have recently been identified to have regulatory effects on the liver. Additionally, AT can produce extracellular vesicles (EVs) that act on peripheral tissues. However, under pathological conditions, such as obesity and diabetes, dysregulation of adipokines is associated with functional changes in AT, which may cause liver diseases. In this review, we focus on the newly discovered adipokines and EVs secreted by AT and highlight their actions on the liver under the context of obesity, nonalcoholic fatty liver diseases (NAFLD), and some other liver diseases. Clarifying the action of adipokines and adipose tissue-derived EVs on the liver would help to identify novel therapeutic targets or biomarkers for metabolic diseases.