Adiponectin in insulin resistance: lessons from translational research

Adiponectin: a pleiotropic hormone with multifaceted roles

Adipose tissue mostly composed of different types of fat is one of the largest endocrine organs in the body playing multiple intricate roles including but not limited to energy storage, metabolic homeostasis, generation of heat, participation in immune functions and secretion of a number of biologically active factors known as adipokines. The most abundant of them is adiponectin. This adipocite-derived hormone exerts pleiotropic actions and exhibits insulin-sensitizing, antidiabetic, anti-obesogenic, anti-inflammatory, antiatherogenic, cardio- and neuroprotective properties. Contrariwise to its protective effects against various pathological events in different cell types, adiponectin may have links to several systemic diseases and malignances. Reduction in adiponectin levels has an implication in COVID-19-associated respiratory failure, which is attributed mainly to a phenomenon called 'adiponectin paradox'. Ample evidence about multiple functions of adiponectin in the body was obtained from animal, mostly rodent studies. Our succinct review is entirely about multifaceted roles of adiponectin and mechanisms of its action in different physiological and pathological states.

Cord Blood IGF-I, Proinsulin, Leptin, HMW Adiponectin, and Ghrelin in Short or Skinny Small-for-Gestational-Age Infants

CONTEXT

Small-for-gestational-age (SGA) is an indicator of poor fetal growth "programming" an elevated risk of type 2 diabetes in adulthood. Little is known about early-life endocrine characteristics in SGA subtypes. Stunting (short) and wasting (skinny) are considered distinct SGA phenotypes in neonatal prognosis.

OBJECTIVES

This work aimed to assess whether SGA infants with stunting or wasting have similar alterations in neonatal endocrine metabolic health biomarkers.

METHODS

This was a nested case-control study based on the 3D (Design, Develop, and Discover) birth cohort in Canada. The study subjects were 146 SGA (birth weight < 10th percentile) and 155 optimal-for-gestational age (OGA, 25th-75th percentiles) infants. Stunting was defined as birth length less than the 10th percentile, and wasting as body mass index less than the 10th percentile for sex and gestational age, respectively. Main outcome measures included cord plasma concentrations of insulin-like growth factor I (IGF-I), proinsulin, leptin, high-molecular-weight (HMW) adiponectin, and ghrelin.

RESULTS

Comparing to OGA infants adjusted for maternal and neonatal characteristics, SGA infants with either stunting only or wasting only had lower cord plasma IGF-I and leptin concentrations. HMW adiponectin concentrations were lower in SGA infants with wasting only (P = .004), but similar in SGA infants with stunting only (P = .816). Only SGA infants with both stunting and wasting had substantially lower proinsulin (P < .001) and higher ghrelin concentrations (P < .001) than OGA infants.

CONCLUSION

This study is the first to demonstrate that SGA infants with wasting only are characterized by low HMW adiponectin concentrations, whereas those with stunting only are not. SGA with both stunting and wasting are characterized by low proinsulin and high ghrelin concentrations.

The effects of twenty-four nutrients and phytonutrients on immune system function and inflammation: A narrative review

BACKGROUND AND AIM

Recently, optimal immune function has become a primary focus of worldwide attention not only in the prevention of chronic disease but also as one strategy to reduce the severity of acute illness. Inflammation, a process largely controlled by the immune system, has long been studied and recognized for its role in chronic disease. Optimizing immune function or managing inflammation using individual nutrients and phytonutrients is not well understood by the average person. Thus, this narrative literature review summarizes many of the more recent findings about how certain nutrients and phytonutrients affect immune function and inflammation, and how they may best be utilized considering the growing worldwide interest in this topic.

METHODS

A comprehensive literature search of PubMed was performed to find clinical trials in humans that assessed the effect of nutrients and phytonutrients on immune function and inflammation, in individuals with acute and chronic health conditions, published in English between 2000 and 2020. Two independent reviewers evaluated the articles for their inclusion.

RESULTS

Eighty-seven articles were summarized in this narrative review. In total 24 nutrients and phytonutrients were included in the study, that is, acetyl-L-carnitine, Aloe vera polysaccharides, beta-glucans, bilberry, black seed oil, coenzyme Q10, curcumin (turmeric), frankincense, garlic, ginger, hydrolyzed rice bran, isoflavones, lipoic acid, mistletoe, N-acetyl cysteine, omega-3 fatty acids, resveratrol, selenium, shiitake mushroom and its derivatives, Vitamin B12, Vitamin C, Vitamin D3 (cholecalciferol), Vitamin E (d-alpha- and gamma-tocopherol), and zinc. Some of the noteworthy immune function and anti-inflammatory responses to these interventions included modulation of nuclear factor-Kappa B, tumor necrosis factor-a, interferon-g, interleukin-6, and CD4+ T cells, among others. These findings are not completely consistent or ubiquitous across all patient populations or health status.

CONCLUSIONS

Based on this review, many nutrients and phytonutrients are capable of significantly modulating immune function and reducing inflammation, according to multiple biomarkers in clinical trials in different populations of adults with varying health statuses. Thus, dietary supplementation may serve as an adjunct to conventional pharmaceutical or medical therapies, but evaluation of risks and benefits for each person and health status is necessary. Additional larger studies are also needed to investigate the safety and efficacy of nutritional compounds in various health conditions, with emphases on potential drug-supplement interactions and clinical endpoints.

RELEVANCE FOR PATIENTS

As demonstrated in the reviewed clinical trials, patients of various health challenges with a wide range of severity may benefit from select nutrients and phytonutrients to improve their immune function and reduce inflammation.

Impact of obesity on survival of patients with myelodysplastic syndromes

Background: Obesity has been associated with increased incidence of myelodysplastic syndromes (MDS). Recently intriguing data in mouse models suggested that obesity increases survival in animals with MDS.Methods: This was a retrospective analysis using the Moffitt MDS database. Obesity was defined by using body mass index (BMI), whereby a BMI ≥ 30 was regarded as obese.Results: Among 3089 MDS patients with known BMI, 963 patients (31%) were categorized as obese. There were no differences in baseline characteristics between patients with BMI ≥ 30 and those with <30. The median OS for patients with BMI ≥ 30 was 34 months compared to 37 months for those with BMI < 30 (p 0.04). For patients with lower-risk MDS median OS was 52 months versus 57 months, respectively, (p 0.08) while for higher-risk patients median OS was 17 months for both groups. The rate of AML transformation was 36% for patients with BMI ≥ 30 compared to 32% for those with BMI < 30 (p 0.009). There was no difference in response to azacitidine. In multivariable analysis, BMI was associated with inferior OS. For patients < 45 years old, the median OS was 25 months for patients with BMI ≥ 30 compared to 116 months for those with BMI < 30 (p 0.034).Conclusions: Obesity is associated with inferior overall survival (OS) in MDS patients in less than 65 years old and lower MDS risk. Impact of obesity on the outcome of MDS is being explored in both mice and human. Here we reported the impact of obesity on OS in MDS patients. Obesity is associated with inferior OS in MDS patients particularly younger age groups and lower MDS risk.

The Role of HIV Infection in the Pathophysiology of Gestational Diabetes Mellitus and Hypertensive Disorders of Pregnancy

Purpose of the Review: The main objective of this study is to investigate mechanisms associated with gestational diabetes mellitus (GDM) and hypertensive disorders of pregnancy (HDP) in HIV infected pregnant women by looking how placental hormones such as (progesterone and prolactin) and basic haemostatic parameters are regulated in HIV infected pregnancies.

Recent Findings: HIV/AIDS are a major global obstetric health burden that lead to increased rate of morbidity and mortality. HIV/AIDS has been associated with the pathophysiology of GDM and HDP. Increased risk of GDM due to highly active antiretroviral therapy (HAART) usage has been reported in HIV infected pregnancies, which causes insulin resistance in both pregnant and non-pregnant individuals. HAART is a medication used for lowering maternal antepartum viral load and pre-exposure and post-exposure prophylaxis of the infant. In pregnant women, HAART induces diabetogenic effect by causing dysregulation of placental hormones such as (progesterone and prolactin) and predispose HIV infected women to GDM. In addition to HIV/AIDS and GDM, Studies have indicated that HIV infection causes haemostatic abnormalities such as hematological disorder, deregulated haematopoiesis process and the coagulation process which results in HDP.

Summary: This study will help on improving therapeutic management and understanding of the pathophysiology of GDM and HDP in the absence as well as in the presence of HIV infection by reviewing studies reporting on these mechanism.

β-Sitosterol Circumvents Obesity Induced Inflammation and Insulin Resistance by down-Regulating IKKβ/NF-κB and JNK Signaling Pathway in Adipocytes of Type 2 Diabetic Rats

β-sitosterol (SIT), the most abundant bioactive component of vegetable oil and other plants, is a highly potent antidiabetic drug. Our previous studies show that SIT controls hyperglycemia and insulin resistance by activating insulin receptor and glucose transporter 4 (GLUT-4) in the adipocytes of obesity induced type 2 diabetic rats. The current research was undertaken to investigate if SIT could also exert its antidiabetic effects by circumventing adipocyte induced inflammation, a key driving factor for insulin resistance in obese individuals. Effective dose of SIT (20 mg/kg b.wt) was administered orally for 30 days to high fat diet and sucrose induced type-2 diabetic rats. Metformin, the conventionally used antidiabetic drug was used as a positive control. Interestingly, SIT treatment restores the elevated serum levels of proinflammatory cytokines including leptin, resistin, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) to normalcy and increases anti-inflammatory adipocytokines including adiponectin in type 2 diabetic rats. Furthermore, SIT decreases sterol regulatory element binding protein-1c (SREBP-1c) and enhances Peroxisome Proliferator–activated receptor-γ (PPAR-γ) gene expression in adipocytes of diabetic rats. The gene and protein expression of c-Jun-N-terminal kinase-1 (JNK1), inhibitor of nuclear factor kappa-B kinase subunit beta (IKKβ) and nuclear factor kappa B (NF-κB) were also significantly attenuated in SIT treated groups. More importantly, SIT acts very effectively as metformin to circumvent inflammation and insulin resistance in diabetic rats. Our results clearly show that SIT inhibits obesity induced insulin resistance by ameliorating the inflammatory events in the adipose tissue through the downregulation of IKKβ/NF-κB and c-Jun-N-terminal kinase (JNK) signaling pathway.

Dietary glycemic index, glycemic load, insulin index, insulin load and risk of diabetes-related cancers: A systematic review of cohort studies

BACKGROUND & AIMS

It is believed that diets high in glycemic index (GI), glycemic load (GL), Insulin index (II), and Insulin load (IL) are associated with the increased risks of certain cancers through increasing serum glucose or insulin levels.

METHODS

We conducted this systematic review of cohort studies to evaluate the possible relation between GI, GL, II, and IL with diabetes-related cancers, including colorectal, bladder, breast, endometrium, liver, pancreas, and prostate cancers. Two separate investigators conducted a literature search through PubMed/Medline, Scopus, and Web of Science databases up to February 2020, plus reference lists of relevant articles.

RESULTS

Fifty-three cohort studies with a total of 100 098 cancer cases were included in this systematic review. Fifteen out of eighteen studies among breast cancer cases reported no significant association between GI/GL and cancer risk. These numbers were 4 out of 13 for colorectal cancer, 7 out of 9 for endometrial cancer, 2 out of 3 for liver cancer, 8 out of 10 for pancreatic cancer, and 3 out of 3 for prostate cancer. Only one cohort investigated this association in terms of bladder cancer and reported a significant association. Also, five studies reported this relation in terms of II/IL, and only one cohort among endometrial cancer patients observed a significant positive association between the risk of cancer and IL.

CONCLUSION

We concluded a weak association between dietary GI/GL and no association between II/IL with diabetes-related cancer risk. More cohort studies are required to be performed regarding II/IL and the risk of cancer.

Hepatokines and adipokines in NASH-related hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) is increasing in industrialised societies; this is likely secondary to the increasing burden of non-alcoholic fatty liver disease (NAFLD), its progressive form non-alcoholic steatohepatitis (NASH), and the metabolic syndrome. Cumulative studies suggest that NAFLD-related HCC may also develop in non-cirrhotic livers. However, prognosis and survival do not differ between NAFLD- or virus-associated HCC. Thus, research has increasingly focused on NAFLD-related risk factors to better understand the biology of hepatocarcinogenesis and to develop new diagnostic, preventive, and therapeutic strategies. One important aspect thereof is the role of hepatokines and adipokines in NAFLD/NASH-related HCC. In this review, we compile current data supporting the use of hepatokines and adipokines as potential markers of disease progression in NAFLD or as early markers of NAFLD-related HCC. While much work must be done to elucidate the mechanisms and interactions underlying alterations to hepatokines and adipokines, current data support the possible utility of these factors - in particular, angiopoietin-like proteins, fibroblast growth factors, and apelin - for detection or even as therapeutic targets in NAFLD-related HCC.

Coffee consumption and risk of prostate cancer: a systematic review and meta-analysis

OBJECTIVES

To conduct a systematic review with meta-analysis of cohort studies to evaluate the association of coffee consumption with the risk of prostate cancer.

DATA SOURCES

PubMed, Web of Science and Embase were searched for eligible studies up to September 2020.

STUDY SELECTION

Cohort studies were included.

DATA EXTRACTION AND SYNTHESIS

Two researchers independently reviewed the studies and extracted the data. Data synthesis was performed via systematic review and meta-analysis of eligible cohort studies. Meta-analysis was performed with the "metan" and "glst" commands in Stata 14.0.

MAIN OUTCOMES AND MEASURES

Prostate cancer was the main outcome. It was classified as localised prostate cancer which included localised or non-aggressive cancers; advanced prostate cancer which included advanced or aggressive cancers; or fatal prostate cancer which included fatal/lethal cancers or prostate cancer-specific deaths.

RESULTS

Sixteen prospective cohort studies were finally included, with 57 732 cases of prostate cancer and 1 081 586 total cohort members. Higher coffee consumption was significantly associated with a lower risk of prostate cancer. Compared with the lowest category of coffee consumption, the pooled relative risk (RR) was 0.91 (95% CI 0.84 to 0.98), I²= 53.2%) for the highest category of coffee consumption. There was a significant linear trend for the association (p=0.006 for linear trend), with a pooled RR of 0.988 (95% CI 0.981 to 0.995) for each increment of one cup of coffee per day. For localised, advanced and fatal prostate cancer, the pooled RRs were 0.93 (95% CI 0.87 to 0.99), 0.88 (95% CI 0.71 to 1.09) and 0.84 (95% CI 0.66 to 1.08), respectively. No evidence of publication bias was indicated in this meta-analysis.

CONCLUSIONS

This study suggests that a higher intake of coffee may be associated with a lower risk of prostate cancer.

Emodin Improves Glucose and Lipid Metabolism Disorders in Obese Mice via Activating Brown Adipose Tissue and Inducing Browning of White Adipose Tissue

BACKGROUND

Adipose tissue (e.g. white, brown and brite) plays a critical role in modulating energy metabolism. Activating brown adipose tissue (BAT) and inducing browning in white adipose tissue (WAT) has been proposed to be a potential molecular target for obesity treatment. Emodin is a natural anthraquinone derivative that exhibits variety of pharmacologic effects including lowering lipids and regulating glucose utilization. However, the underlying mechanism of action is still unclear. In the present study, we investigated whether emodin could alleviate obesity via promoting browning process in adipose tissue.

METHODS

C57BL/6J mice were fed with high fat diet to induce obesity. Emodin at the doses of 40 and 80 mg/kg were orally given to obesity mice for consecutive 6 weeks. Parameters including fasting blood glucose, oral glucose tolerance, blood lipids, and the ratios of subcutaneous white adipose tissue (scWAT) or BAT mass to body weight, and morphology of adipose tissue were observed. Besides, the protein expression of uncoupling protein 1 (UCP1) and prohibitin in BAT and scWAT was determined by immunohistochemistry method. Relative mRNA expression of Cd137, transmembrane protein 26 (Tmem26) and Tbx1 in scWAT was analyzed using qRT-PCR. And the protein expression of UCP1, CD36, fatty acid transporter 4 (FATP4), peroxisome proliferator-activated receptor alpha (PPARα) and prohibitin of scWAT and BAT were analyzed using western blotting. In addition, ultra-high-performance liquid chromatography with electrospray ionization tandem mass spectrometry was utilized to detect the small lipid metabolites of scWAT and BAT.

RESULTS

Emodin decreased the body weight and food intake in HFD-induced obesity mice, and it also improved the glucose tolerance and reduced the blood lipids. Emodin treatment induced beiging of WAT, and more multilocular lipid droplets were found in scWAT. Also, emodin significantly increased markers of beige adipocytes, e.g. Cd137, Tmem26 and Tbx1 mRNA in scWAT, and UCP1, CD36, FATP4, PPARα and prohibitin protein expression in scWAT and BAT. Furthermore, emodin perturbed the lipidomic profiles in scWAT and BAT of obese mice. Emodin increased total ceramides (Cers), lysophosphatidylcholines (LPCs), lyso-phosphatidylcholines oxygen (LPCs-O), and phosphatidylethanolamines oxygen (PEs-O) species concentration in scWAT. Specifically, emodin significantly up-regulated levels of Cer (34:1), LPC (18:2), LPC-(O-20:2), PC (O-40:7), PE (O-36:3), PE (O-38:6), PE (O-40:6), and sphingolipid (41:0) [SM (41:0)], and down-regulated PC (O-38:0), PE (O-40:4), PE (O-40:5) in scWAT of obesity mice. In terms of lipid matabolites of BAT, the emodin remarkably increased the total PCs levels, which was driven by significant increase of PC (30:0), PC (32:1), PC (32:2), PC (33:4) and PC (38:0) species. In addition, it also increased species of LPCs, e.g. LPC (20:0), LPC (20:1), LPC (22:0), LPC (22:1), LPC (24:0), and LPC (24:1). Especially, emodin treatment could reverse the ratio of PC/PE in HFD-induced obese mice.

CONCLUSIONS

These results indicated that emodin could ameliorate adiposity and improve metabolic disorders in obese mice. Also, emodin could promote browning in scWAT and activate the BAT activities. In addition, emodin treatment-induced changes to the scWAT and BAT lipidome were highly specific to certain molecular lipid species, indicating that changes in tissue lipid content reflects selective remodeling in scWAT and BAT of both glycerophospholipids and sphingolipids in response to emodin treatment.

Positive association between dietary acid load and future insulin resistance risk: findings from the Korean Genome and Epidemiology Study

Background

Acid-base homeostasis is increasingly being recognized to play an important role in normal metabolic function. However, prospective studies on the relationship between diet-induced acid-base imbalance and insulin resistance among Asian populations have been limited. Thus, we investigated whether diet-induced metabolic acidosis was prospectively associated with insulin resistance risk in middle-aged and older Korean adults.

Methods

In total, 5406 participants from the Korean Genome and Epidemiology Study without type 2 diabetes, insulin resistance, cancer, or renal diseases at baseline examination were included in this study. To estimate diet-induced metabolic acidosis, we used potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores calculated from the usual dietary intake assessed by a validated 103-item food frequency questionnaire at baseline. Multivariable Cox proportional hazard models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of insulin resistance incidence.

Results

During a mean follow-up period of 7.4 years, we documented 3449 insulin resistance cases. In the fully adjusted model, the future insulin resistance risk was significantly higher among participants in the highest quartiles of PRAL (HR: 1.30, 95% CI: 1.13–1.48, P_trend = 0.0002) and NEAP (HR: 1.30, 95% CI: 1.14–1.49, P_trend = 0.0008) than among those in the lowest quartiles. Associations were slightly strengthened among men, adults < 50 years old, obese participants, or those with low physical activity levels.

Conclusions

Our findings suggested that diet-dependent acid load was positively associated with the future development of insulin resistance, suggesting effect modification by sex, age, the presence of obesity, and physical activity levels.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-020-00653-6.

The role of insulin resistance in the relation of visceral, abdominal subcutaneous and total body fat to cardiovascular function

BACKGROUND AND AIMS

The separate cardiovascular effects of type 2 diabetes and adiposity remain to be examined. This study aimed to investigate the role of insulin resistance in the relations of visceral (VAT), abdominal subcutaneous (aSAT) adipose tissue and total body fat (TBF) to cardiovascular remodeling.

METHODS AND RESULTS

In this cross-sectional analysis of the population-based Netherlands Epidemiology of Obesity study, 914 middle-aged individuals (46% men) were included. Participants underwent magnetic resonance imaging. Standardized linear regression coefficients (95%CI) were calculated, adjusted for potential confounding factors. All fat depots and insulin resistance (HOMA-IR), separate from VAT and TBF, were associated with lower mitral early and late peak filling rate ratios (E/A): -0.04 (-0.09;0.01) per SD (54 cm²) VAT; -0.05 (-0.10;0.00) per SD (94 cm²) aSAT; -0.09 (-0.16;-0.02) per SD (8%) TBF; -0.11 (-0.17;-0.05) per 10-fold increase in HOMA-IR, whereas VAT and TBF were differently associated with left ventricular (LV) end-diastolic volume: -8.9 (-11.7;-6.1) mL per SD VAT; +5.4 (1.1;9.7) mL per SD TBF. After adding HOMA-IR to the model to evaluate the mediating role of insulin resistance, change in E/A was -0.02 (-0.07;0.04) per SD VAT; -0.03 (-0.08;0.02) per SD aSAT; -0.06 (-0.13;0.01) per SD TBF, and change in LV end-diastolic volume was -7.0 (-9.7;-4.3) mL per SD VAT. In women, adiposity but not HOMA-IR was related to higher aortic arch pulse wave velocity.

CONCLUSION

Insulin resistance was associated with reduced diastolic function, separately from VAT and TBF, and partly mediated the associations between adiposity depots and lower diastolic function.

Anti-Obesity Effects of a Prunus persica and Nelumbo nucifera Mixture in Mice Fed a High-Fat Diet

Prunus persica and Nelumbo nucifera are major crops cultivated worldwide. In East Asia, both P. persica flowers and N. nucifera leaves are traditionally used for therapeutic purposes and consumed as teas for weight loss. Herein, we investigated the anti-obesity effects of an herbal extract mixture of P. persica and N. nucifera (HT077) and the underlying mechanism using a high-fat diet (HFD)-induced obesity model. Male C57BL/6 mice were fed a normal diet, HFD, HFD containing 0.02% orlistat (positive control), or HFD containing 0.1, 0.2, or 0.4% HT077 for 12 weeks. HT077 significantly reduced final body weights, weight gain, abdominal fat weights, liver weights, and hepatic levels of triglycerides and total cholesterol. HT077 also lowered glucose, cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and leptin levels and increased AST/ALT and adiponectin/leptin ratios and adiponectin levels. Real-time polymerase chain reaction analysis showed that HT077 decreased the expression of lipogenic genes and increased the expression of fatty acid oxidation-related genes in adipose tissue. Our results indicate that HT077 exerts anti-obesity effects and prevents the development of obesity-related metabolic disorders. These beneficial effects might be partially attributed to ameliorating adipokine imbalances and regulating lipid synthesis and fatty acid oxidation in adipose tissue.

Fufang-Zhenzhu-Tiaozhi capsule ameliorates rabbit's iliac artery restenosis by regulating adiponectin signaling pathway

BACKGROUND AND PURPOSE

Fufang-Zhenzhu-Tiaozhi Capsule (FTZ), a traditional Chinese medicine, has been shown obvious effects on the treatment of dyslipidemia and atherosclerosis. The aim of this study was to evaluate whether FTZ can ameliorate rabbit iliac artery restenosis after angioplasty by regulating adiponectin signaling pathway.

EXPERIMENTAL APPROACH

The rabbit iliac artery restenosis model was established through percutaneous iliac artery transluminal balloon angioplasty and a high-fat diet. Twenty eight male New Zealand rabbits (8-week-old) were divided into sham operation group (Group Ⅰ), model group (Group Ⅱ), atorvastatin group (Group Ⅲ) and FTZ group (Group Ⅳ), with 7 rabbits in each group. Vascular stenosis was analyzed with Digital Subtraction Angiography. Level of adiponectin (APN), and inflammatory factor including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) as well as monocyte chemoattractant protein-1 (MCP-1) was measured by Enzyme Linked Immunosorbent Assay; and injured iliac artery was collected for Hematoxylin-eosin staining and Western Blotting detection of expression of peroxisome proliferator-activated receptor-alpha (PPAR-α), adenosine 5'-monophosphate -activated protein kinase (AMPK) and phosphorylated adenosine 5'-monophosphate -activated protein kinase (p-AMPK). Besides, we evaluated FTZ's safety for the first time.

KEY RESULTS

Percutaneous iliac artery transluminal balloon angioplasty and high-fat diet result in inflammatory response and restenosis. Compared with Group Ⅱ, iliac artery restenosis was significantly ameliorated in Group Ⅳ (P < 0.05). Treated with FTZ, serum lipids were significantly decreased (P < 0.01), while the level of APN was elevated significantly (P < 0.01). Western blotting detection of the injured iliac artery showed that the expressions of PPAR-α, AMPK and p-AMPK were significantly increased in Group Ⅳ (P < 0.01) than that in Group Ⅱ. Besides, before and after taking drugs, liver and kidney function indicators, creatine kinase, as well as measurement of echocardiography were of no statistical difference in four groups(P > 0.05).

CONCLUSIONS AND IMPLICATIONS

FTZ could effectively reduce serum lipids and ameliorate rabbit's iliac artery restenosis after angioplasty, and its mechanism may be related to activation of APN signaling pathway.

Adiponectin in onset and progression of T2DM with cardiac dysfunction in rats

Cardiovascular disease and type 2 diabetes mellitus (T2DM) patients have low level of adiponectin, however, till now the role of adiponectin in progression of ‘T2DM with cardiac dysfunction’ in animal model has not been characterized. Therefore, the aim of the present study was to develop and characterize T2DM animal model with cardiac dysfunction and to study the role of cardiac adiponectin expression in cardiac dysfunction. For this, Wistar rats (M/F) were fed a high-fat diet for different time periods: 3, 4 and 5 weeks and given a single, low-dose streptozotocin (25mg/kg), intraperitoneal injection 1 week prior to the experiments. Rats in T2DM group (3 weeks) developed hyperglycaemia, hyperlipidaemia, oxidative stress with normoinsulinaemia and mild cardiac dysfunction suggesting onset of T2DM with cardiac dysfunction. Extended high-fat feeding, that is, 4 and 5 weeks induced insulin resistance accompanied with cardiac hypertrophy, cardiac dysfunction and reduced baroreflex sensitivity indicating development of T2DM with cardiac dysfunction. Cardiac adiponectin expression did not change in rats of T2DM group (3 weeks), however, it significantly decreased in rats of two T2DM groups (4 and 5 weeks) along with increased intracellular adhesion molecule-1 levels. Thus, the present study for the first time indicates that in the present T2DM animal model, as T2DM progresses cardiac adiponectin expression also decreases which might be the precipitating factor for cardiac hypertrophy and decrease in baroreflex sensitivity, which induces cardiac dysfunction.

Novel insights into adiponectin action in breast cancer: Evidence of its mechanistic effects mediated by ERα expression

This review describes the multifaceted effects of adiponectin on breast cancer cell signalling, tumour metabolism, and microenvironment. It is largely documented that low adiponectin levels are associated with an increased risk of breast cancer. However, it needs to be still clarified what are the extents of the decrease of local/intra-tumoural adiponectin concentrations, which promote breast tumour malignancy. Most of the anti-proliferative and pro-apoptotic effects induced by adiponectin have been obtained in breast cancer cells not expressing estrogen receptor alpha (ERα). Here, we will highlight recent findings demonstrating the mechanistic effects through which adiponectin is able to fuel genomic and non-genomic estrogen signalling, inhibiting LKB1/AMPK/mTOR/S6K pathway and switching energy balance. Therefore, it emerges that the reduced adiponectin levels in patients with obesity work to sustain tumour growth and progression in ERα-positive breast cancer cells. All this may contribute to remove the misleading paradigm that adiponectin univocally inhibits breast cancer cell growth and progression independently on ERα status. The latter concept, here clearly provided by pre-clinical studies, may have translational relevance adopting adiponectin as a potential therapeutic tool. Indeed, the interfering role of ERα on adiponectin action addresses how a separate assessment of adiponectin treatment needs to be considered in novel therapeutic strategies for ERα-positive and ERα-negative breast cancer.

Triphenyl phosphate causes a sexually dimorphic metabolism dysfunction associated with disordered adiponectin receptors in pubertal mice

The potential for triphenyl phosphate (TPhP) caused metabolic dysfunction has been documented. However, the relative mechanism of sexual dimorphic disruption on metabolism induced by TPhP remains unclear. Herein, we observed the insulin-sensitizing hormone (adiponectin) was inhibited in female serum while stimulated in males after oral administration of TPhP. Correspondingly, we found a high index of HOMA-IR in females. The primary receptors of adiponectin (AdipoR1 and AdipoR2) and the downstream: phosphorylation of AKT (pAKT) and PPAR⍺ signaling was attenuated in female liver. The disordered adiponectin/AdipoR signaling reduced hepatic glucose glycolysis and induced gluconeogenesis and finally led to the glucose intolerance in females. Also, the aberrant fatty acid β-oxidation and hepatic triacylglyceride (TG) deposition were found in female liver. Comparably, TPhP upregulated the AdipoR 1/2 and induced the downstream (pAMPK and PPAR⍺ signaling) in males. Thus, the serum glucose and hepatic TG level remained normal. However, modulation on AdipoR1/R2 and the genes related to glucose and lipid disposal in skeletal muscle has no gender-specific effect. Our research firstly revealed TPhP-induced hepatic nutrient metabolism was partially mediated by the adiponectin/AdipoR pathway in sexual-dependent manner during pubertal.

Characterization and Pharmacological Evaluation of Anti-Cellulite Herbal Product(s) Encapsulated in 3D-Fabricated Polymeric Microneedles

Skin health is vital for a healthy body. Herbal remedies have long been used for skin care, and their global use has tremendously increased over the past three decades. Although cellulite is seen as a normal condition by the medical community, it is considered a serious cosmetic concern for most affected women. Many topical anti-cellulite creams are available on the market, but unfortunately, their efficacy has not been proven scientifically. Microneedles (MNs) represent a new approach to enhance the permeation of loaded medication through the skin. In this study, the anti-cellulite effects of Vitex agnus-castus and Tamarindus indica extracts were compared using safe and effective polymeric MNs. This delivery system offers a painless alternative to the combined treatment strategy of microneedling devices and anti-cellulite products. The selected standardized extracts were evaluated for their mineral, phenolic and flavonoid contents, which are correlated to a promising antioxidant effect, as demonstrated by an in vitro radical scavenging activity assay. 3D-printing techniques were chosen for fabrication of a micromold, which is inexpensive for mass production. To ensure that MNs were sufficiently strong to perforate the skin without breaking, axial failure force was measured using a micro-mechanical test machine. The anticellulite effects of MNs were assessed using an in vivo diet-induced obesity guinea pig model. Skin properties, histopathology and inflammatory markers were examined. MNs loaded with plant extracts were statistically comparable in normalizing the oxidative state and reducing inflammation, while myeloperoxidase levels were more significantly reduced by T. indica than by V. agnus-castus. This novel delivery system opens the door for new transdermal strategies for cellulite management.

Adiponectin (ADIPOQ) gene variants and haplotypes in Saudi Arabian women with polycystic ovary syndrome (PCOS): a case-control study

The aim of this study is to assess the association of nine SNPs on ADIPOQ on the PCOS risk among Saudi Arabian Women. A case-control study, including 162 cases and 162 controls in Saudi Arabia, was enrolled. Genotyping was carried out by the allelic discrimination method. Estimated haplotype frequencies were assessed using the maximum likelihood method. Results showed that ADIPOQ SNPs were not associated with PCOS for allelic and genotypic frequencies (p > .05). In haplotype estimation analysis, a significant positive association was detected between 21211 haplotype (rs2241766/rs1501299/rs2241767/rs3774261/rs17366743) in additive model with increased risk of PCOS (p = .009, OR = 2.16 [1.22-3.82] CI 95%). None of the nine SNPs illustrated significant association with the quantitative traits after multiple test corrections. These results support a significant association of 21211 haplotype (rs2241766/rs1501299/rs2241767/rs3774261/rs17366743) of ADIPOQ gene in Saudi women with polycystic ovary syndrome.

Effects of two types of energy restriction on methylation levels of adiponectin receptor 1 and leptin receptor overlapping transcript in a mouse mammary tumour virus-transforming growth factor-α breast cancer mouse model

The role of adiponectin and leptin signalling pathways has been suggested to play important roles in the protective effects of energy restriction (ER) on mammary tumour (MT) development. To study the effects of ER on the methylation levels in adiponectin receptor 1 (AdipoR1) and leptin receptor overlapping transcript (Leprot) genes using the pyrosequencing method in mammary fat pad tissue, mouse mammary tumour virus-transforming growth factor-α (MMTV-TGF-α) female mice were randomly assigned to ad libitum (AL), chronic ER (CER, 15 % ER) or intermittent ER (3 weeks AL and 1 week 60 % ER in cyclic periods) groups at 10 weeks of age until 82 weeks of age. The methylation levels of AdipoR1 in the CER group were higher than those in the AL group at week 49/50 (P < 0·05), while the levels of methylation for AdipoR1 and Leprot genes were similar among the other groups. Also, the methylation levels at CpG2 and CpG3 regions of the promoter region of the AdipoR1 gene in the CER group were three times higher (P < 0·05), while CpG1 island of Leprot methylation was significantly lower compared with the other groups (P < 0·05). Adiponectin and leptin gene expression levels were consistent with the methylation levels. We also observed a change with ageing in methylation levels of these genes. These results indicate that different types of ER modify methylation levels of AdipoR1 and Leprot in different ways and CER had a more significant effect on methylation levels of both genes. Epigenetic regulation of these genes may play important roles in the preventive effects of ER against MT development and ageing processes.

Therapeutic Effect of Topical Adiponectin-Derived Short Peptides Compared with Globular Adiponectin in Experimental Dry Eye and Alkali Burn

Purpose: To evaluate the efficacy of adiponectin (APN)-derived short peptides (ADPs) 355 compared with globular APN in a mouse model of experimental dry eye (EDE) and corneal alkali burn. Methods: EDE and chemical burn were induced in C57BL/6 mice by desiccating stress and application of NaOH, respectively. Eye drops consisting of 0.01% globular APN, 0.01% ADPs, 0.1% ADPs, or balanced salt solution (BSS) were applied. Tear volume, tear film break-up time, and corneal staining scores were measured. Concentrations of interleukin (IL)-1β, interferon (IFN)-γ, IL-6, CXCL-9, and CXCL-10 using multiplex immunobead assay were evaluated, and flow cytometry were performed. Corneal epithelial defects and haze degree were analyzed, and enzyme-linked immunosorbent assay for IL-1β and transforming growth factor (TGF)-β levels were observed. Results: All treatment groups showed an improvement in clinical parameters and CD4+CCR5+ T cell and CD11b+ cell infiltrations in the conjunctiva (all P < 0.05). Both ADPs groups had significantly decreased concentrations of IL-1β, IFN-γ, IL-6, CXCL-9, and CXCL-10 in the conjunctiva than the EDE or BSS group. Significantly improved parameters of epithelial defect, degree of haze, and concentrations of IL-1β and TGF-β were observed in all treatment groups. However, no significant differences were noted in clinical or experimental parameters among treatment groups. Conclusion: Topical ADPs could effectively improve clinical signs and inflammation of ocular surface in the EDE or alkali burn, and its efficacy and potency were similar to those of globular APN.

Insulin resistance and body composition in cancer patients

Cancer cachexia, weight loss with altered body composition, is a multifactorial syndrome propagated by symptoms that impair caloric intake, tumor byproducts, chronic inflammation, altered metabolism, and hormonal abnormalities. Cachexia is associated with reduced performance status, decreased tolerance to chemotherapy, and increased mortality in cancer patients. Insulin resistance as a consequence of tumor byproducts, chronic inflammation, and endocrine dysfunction has been associated with weight loss in cancer patients. Insulin resistance in cancer patients is characterized by increased hepatic glucose production and gluconeogenesis, and unlike type 2 diabetes, normal fasting glucose with high, normal or low levels of insulin. Cancer cachexia results in altered body composition with the loss of lean muscle mass with or without the loss of adipose tissue. Alteration in visceral adiposity, accumulation of intramuscular adipose tissue, and secretion of adipocytokines from adipose cells may play a role in promoting the metabolic derangements associated with cachexia including a proinflammatory environment and insulin resistance. Increased production of ghrelin, testosterone deficiency, and low vitamin D levels may also contribute to altered metabolism of glucose. Cancer cachexia cannot be easily reversed by standard nutritional interventions and identifying and treating cachexia at the earliest stage of development is advocated. Experts advocate for multimodal therapy to address symptoms that impact caloric intake, reduce chronic inflammation, and treat metabolic and endocrine derangements, which propagate the loss of weight. Treatment of insulin resistance may be a critical component of multimodal therapy for cancer cachexia and more research is needed.

Interactions among moderate/severe periodontitis, ADIPOQ-rs1501299, and LEPR-rs1137100 polymorphisms on the risk of type 2 diabetes in a Chinese population

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is a complex disease influenced by genes and the environment. Periodontitis a demonstrated risk factor of T2DM. Previous studies related to gene-environment interactions on the risk of T2DM mainly focused on gene-obesity interactions. However, the impact of gene-periodontitis interaction on the risk of T2DM has not yet been investigated. This study aimed to investigate gene-environment interactions among moderate/severe periodontitis, polymorphisms of adiponectin (ADIPOQ)-rs1501299, and leptin receptor (LEPR)-rs1137100 on T2DM risk in Chinese subjects.

DESIGN

A case-control study was conducted in 239 Chinese participants from Beijing Hypertension Association Institute (BHAL). After full-mouth periodontal examinations, the participants underwent bilateral buccal swabs for DNA testing. ADIPOQ-rs1501299 and LEPR-rs1137100 were used for genotyping. Generalised multifactor dimensionality reduction (GMDR) and logistic regression were used to examine the interactions among single nucleotide polymorphisms (SNPs) and moderate/severe periodontitis on the risk of T2DM.

RESULTS

The risk of T2DM was higher in moderate/severe periodontitis [adjusted odds ratio (AOR) = 3.67, 95% confidence interval (95%CI): 1.26-10.71] in ADIPOQ-rs1501299 GG genotype (AOR = 3.42, 95%CI: 1.81-6.46) and LEPR-rs1137100 GG genotype (AOR = 3.16, 95%CI: 1.56-6.39). The GMDR model indicated that there was a significant three-factor model (p = 0.001) involving rs1501299, rs1137100, and moderate/severe periodontitis, demonstrating a potential gene-environment interaction among periodontitis, polymorphisms of rs1501299, and rs1137100 influencing the risk of T2DM. Moderate/severe periodontitis patients with rs1501299-GG and rs1137100-GG have the highest T2DM risk after adjusting for age, gender, BMI, WHR, smoking status, alcohol consumption, economic status, and hypertension (AOR = 20.39, 95%CI: 2.64-157.26).

CONCLUSIONS

Interactions among moderate/severe periodontitis, rs1501299-GG, and rs1137100-GG were associated with an increased risk of T2DM. This study may provide a new insight into the effect of gene-environment interactions on T2DM.

The Emerging Role of Adiponectin in Female Malignancies

Obesity, characterized by excess body weight, is now accepted as a hazardous health condition and an oncogenic factor. In different epidemiological studies obesity has been described as a risk factor in several malignancies. Some biological mechanisms that orchestrate obesity-cancer interaction have been discovered, although others are still not completely understood. The unbalanced secretion of biomolecules, called "adipokines", released by adipocytes strongly influences obesity-related cancer development. Among these adipokines, adiponectin exerts a critical role. Physiologically adiponectin governs glucose levels and lipid metabolism and is fundamental in the reproductive system. Low adiponectin circulating levels have been found in obese patients, in which its protective effects were lost. In this review, we summarize the epidemiological, in vivo and in vitro data in order to highlight how adiponectin may affect obesity-associated female cancers.

Serum levels of CTRP3 in diabetic nephropathy and its relationship with insulin resistance and kidney function

Background

C1q TNF related protein 3 (CTRP3) is an adipokine secreted from adipose tissue. Previous studies have suggested that CTRP3 improves insulin sensitivity and reduces inflammation. Human studies have evaluated circulating levels of this adipokine in patients with diabetes mellitus (DM), diabetic retinopathy, metabolic syndrome, and coronary artery diseases. However, circulating levels of this adipokine in patients with diabetic nephropathy have not been evaluated. The present study aimed to assess serum levels of CTRP3 in patients with type 2 diabetes mellitus (T2DM) and diabetic nephropathy (T2DM-NP) and its relationship with metabolic and inflammatory markers.

Methods

This cross-sectional study was performed on 55 controls, 54 patients with T2DM, and 55 patients with T2DM-NP. Serum levels of CTRP3, adiponectin, TNF-α, and IL-6 were measured by ELISA technique.

Results

Serum levels of CTRP3 were significantly lower in patients with T2DM (257.61 ± 69.79 ng/mL, p < 0.001) and T2DM-NP (222.03 ± 51.99 ng/mL, p < 0.001) compared to controls (328.17 ± 80.73 ng/mL), and those with T2DM-NP compared to T2DM group. CTRP3 was independently associated with HOMA-IR (r = -0.327, p < 0.05) and adiponectin (r = 0.436, p < 0.01) in T2DM group. In T2DM-NP patients, CTRP3 independently was associated with eGFR (r = 0.428, p < 0.01) and HOMA-IR (r = -0.436, p < 0.01). Furthermore, CTRP3 revealed a ability to differentiate T2DM-NP patients from controls (area under curve (95% confidence interval): 0.881 (0.820–0.943) and p < 0.001).

Conclusion

Decreased serum levels of CTRP3 in patients with T2DM and diabetic nephropathy and its association with pathologic mechanism in these patients suggested a possible role for CTRP3 in pathogenesis of diabetic nephropathy; nevertheless, further studies are required in this regard.

Association of serum adiponectin with breast cancer: A meta-analysis of 27 case-control studies

BACKGROUND

Emerging published studies have indicated that adiponectin is involved in tumorigenesis of breast cancer. However, the results of available studies were inconsistent. The aim of this updated meta-analysis was to assess the association of adiponectin with breast cancer.

MATERIALS AND METHODS

PubMed, EMBASE, Wanfang databases, and the China National Knowledge Infrastructure (CNKI) were systematically searched from inception to June 2018. The mean difference (MD) with 95% confidence interval (CI) were estimated and pooled to investigate the effect sizes.

RESULTS

Twenty-seven eligible articles that met the study criteria were included in the current meta-analysis. Overall, there was an evident inverse association between serum adiponectin levels and breast cancer (MD = -0.29, 95%CI = (-0.38, -0.21), P < .001). Asian subgroup showed a significant negative association between serum adiponectin concentrations and breast cancer in subgroup analysis by ethnicity (MD = -2.19, 95%CI = (-3.45, -0.94), P < .001). However, no statistical significance was found in Caucasian subgroup (MD = -0.65, 95%CI = (-1.47, 0.17), P = 0.12). Additionally, a further subgroup analysis of Asian stratified by menopausal status showed higher concentrations of adiponectin in healthy control group, whether they were premenopausal (MD = -0.85, 95%CI = (-1.50, -0.19), P = .01) or postmenopausal (MD = -2.17, 95%CI = (-4.17, -0.18), P = .03). No significant difference was observed concerning the association between serum adiponectin and breast cancer metastasis (MD = -1.56, 95%CI = (-4.90, 1.78), P = .36).

CONCLUSION

The current meta-analysis suggests that the serum adiponectin may be inversely associated with breast cancer. Decreased serum adiponectin levels in premenopausal women may also be inversely associated with breast cancer risk other than postmenopausal status. In addition, low serum adiponectin levels in Asian women were more likely to be associated with breast cancer risk than Caucasian women.

Long-Term Impact of Neonatal Intake of Oleanolic Acid on the Expression of AMP-Activated Protein Kinase, Adiponectin and Inflammatory Cytokines in Rats Fed with a High Fructose Diet

AMP-activated protein kinase (AMPK) is known to regulate both glucose and lipid metabolism, which play vital roles in the development of metabolic syndrome. One way of regulating AMPK is through hormonal activation using adiponectin. Patients diagnosed with type-2 diabetes (T2D) and obesity exhibit low adiponectin concentration levels in their blood. Moreover, studies have also shown that inflammatory processes play a significant role in the etiology of these metabolic diseases. In this study, the long-term effects of neonatal intake of oleanolic acid (OA) on the AMPK gene, genes associated with glucose transport and lipid metabolism, adiponectin levels, and inflammatory biomarkers in rats fed with a high fructose diet were investigated. Seven day old pups were randomly divided into five groups and treated as follows; 0.5% dimethylsulphoxide v/v in distilled water vehicle control (CON), oleanolic acid (OA, 60 mg/kg), high fructose diet (HF, 20% w/v), high fructose diet combined with oleanolic acid (HF+OA), and high fructose diet combined with metformin (HF+MET, 500 mg/kg). The treatments were administered once daily until day 14. The rats were then weaned at day 21 and fed standard rat chow and had ad libitum access to plain drinking water until day 112. The quantitative polymerase chain reaction (qPCR) was used to analyze the gene expressions of AMPK, Glut-4, Cpt-1, AdipoR1, AdipoR2, TNF-α, and IL-6 in the skeletal muscles. Bio-Plex Pro magnetic bead-based assay was used to measure plasma levels of inflammatory markers (TNF-α, IL-6, VEGF, and MCP-1) while ELISA kits were used to measure adiponectin concentration in blood plasma. The results obtained in this study showed that neonatal supplementation with OA significantly increased AMPK gene expression approximately ~4-fold in OA fed rats compared to those that were fed with HF alone. In addition, glut-4 gene expression was also significantly higher in the OA treatment group compared to all the other experimental groups except the CON group whereas Cpt-1 gene was more expressed when OA was administered alone. Together, these results indicated that OA can play a role in glucose and lipid metabolism gene regulation. Furthermore, the results showed that the OA group had ~1.5-fold increase in adiponectin concentration when comparedto the HF group. Moreover, HF increased levels of inflammatory cytokines, which was attenuated by neonatal administration of OA. Plasma concentration and gene expression in the skeletal muscle for TNF-α and IL-6 were significantly increased in rats that were treated with HF alone when compared to all the other groups. On the contrary, the high levels of TNF-α and IL-6 were reduced when OA was administered. These findings suggest that intake of oleanolic acid during the neonatal stage of development could be a potential strategic intervention for the long-term prevention of metabolic diseases such as T2D and obesity.

Potential Adiponectin Receptor Response Modifier Therapeutics

Many human diseases may benefit from adiponectin replacement therapy, but due to pharmacological disadvantages of the intact protein, druggable options focus on peptidic, and small molecule agonists of the adiponectin receptor. Peptide-based adiponectin replacement drug leads are derived from, or resemble, the active site of globular adiponectin. ADP355, the first-in-class such peptide, exhibits low nanomolar cellular activities, and clinically acceptable efficacies in a series of fibrotic and inflammation-derived diseases. The advantage of small molecule therapies, spearheaded by AdipoRon, is oral availability and extension of utility to a series of metabolic conditions. It is exactly the difficulties in the reliability and readout of the in vitro measures and the wealth of in vivo models that make comparison of the various drug classes complicated, if not impossible. While only a fewer number of maladies could take advantage of adiponectin receptor antagonists, the limited number of these available can be very useful tools in target validation studies. Alternative approaches to direct adiponectin signaling control use upstream adiponectin production inducing therapies but currently these offer relatively limited success compared to direct receptor agonists.

Correlation of Adiponectin With Testosterone in Patients With and Without Type 2 Diabetes and Erectile Dysfunction

The aim of this study was to evaluate the levels of adiponectin in diabetic patients with and without erectile dysfunction (ED). In addition, the correlations of adiponectin with the scores of international index of erectile function (IIEF) and total testosterone levels were explored in diabetic and nondiabetic patients with ED. The study included three groups: Type 2 Diabetic patients (T2DM) with and without ED and a third nondiabetics with ED group, each of 29 patients. Fasting blood glucose (FBG), fasting insulin (FI), homeostasis model assessments of insulin resistance (HOMA-IR index), testosterone and adiponectin levels were evaluated. IIEF was applied to diabetic and nondiabetic patients with ED. The results showed that adiponectin was lower in diabetic patients with ED than in both nondiabetics with ED and diabetics without ED groups (5.23 ± 1.05 vs. 11.38 ± 10.08 and 6.5 ± 2.13; p = .003 and .006 respectively). Testosterone was lower in diabetic patients with ED than in diabetics without ED group (2.52 ± 1.15 vs. 4.1 ± 1.46; p = .024). Testosterone had a direct correlation with adiponectin ( r = .371; p = .001). Both adiponectin and testosterone levels did not correlate with IIEF. In conclusion, the decreased adiponectin and testosterone are associated with ED in T2DM. Testosterone has a direct correlation with circulating adiponectin while both have no correlation with IIEF.

Classic and Novel Adipocytokines at the Intersection of Obesity and Cancer: Diagnostic and Therapeutic Strategies

PURPOSE OF REVIEW

In this review, we investigate the role of classic and novel adipocytokines in cancer pathogenesis synopsizing the mechanisms underlying the association between adipocytokines and malignancy. Special emphasis is given on novel adipocytokines as new evidence is emerging regarding their entanglement in neoplastic development.

RECENT FINDINGS

Recent data have emphasized the role of the triad of overweight/obesity, insulin resistance and adipocytokines in cancer. In the setting of obesity, classic and novel adipocytokines present independent and joint effects on activation of major intracellular signaling pathways implicated in cell proliferation, expansion, survival, adhesion, invasion, and metastasis. Until now, more than 15 adipocytokines have been associated with cancer, and this list continues to expand. While the plethora of circulating pro-inflammatory adipocytokines, such as leptin, resistin, extracellular nicotinamide phosphoribosyl transferase, and chemerin are elevated in malignancies, some adipocytokines such as adiponectin and omentin-1 are generally decreased in cancers and are considered protective against carcinogenesis. Elucidating the intertwining of inflammation, cellular bioenergetics, and adiposopathy is significant for the development of preventive, diagnostic, and therapeutic strategies against cancer. Novel more effective and safe adipocytokine-centered therapeutic interventions may pave the way for targeted oncotherapy.

Discriminatory performance of adiponectin and leptin in the identification of impaired glucose tolerance: The Guangzhou Biobank Cohort Study - Cardiovascular Disease Subcohort

Background

To evaluate the additional discriminatory performance of adiponectin, leptin, and their ratio in the identification of impaired glucose tolerance (IGT) in men and women without diabetes on top of conventional risk factors.

Methods & results

A total of 698 subjects underwent an oral glucose tolerance test (oGTT) and adipocytokine measurements. A comprehensive stepwise selection procedure was performed, followed by c-statistics and integrated discrimination improvement (IDI) analysis. In males, adiponectin levels were significantly lower in the IGT group compared to the non-IGT group (Whitney U test, p < 10–4), whereas leptin levels were significantly higher (p = 0.009) in IGT group. In females, adiponectin and leptin levels were not significantly different between groups (Mann-Whitney U test, p = 0.073 and p = 0.08, respectively). Adjusting for the most informative, sex-specific, clinical and biochemical factors, adiponectin, leptin and their ratio were not found to be significant predictors of the response to the glucose load, when modelled as continuous terms or tertiles. In males, the area-under-the-curve (AUC) for adiponectin was estimated at 0.620 (95% CI: 0.558–0.682) and the addition of adiponectin into the basic model provided a ΔAUC benefit of 0.004, showing no additional discriminatory benefit on top of conventional risk factors (IDI p-value: 0.27), nor did the addition of leptin or their ratio. The results were similar in females.

Conclusions

In Chinese individuals without diabetes, no significant evidence for the potential discriminatory value of adiponectin, leptin or their ratio in the identification of IGT on top of conventional risk factors was observed.

Cord blood insulin, IGF-I, IGF-II, leptin, adiponectin and ghrelin, and their associations with insulin sensitivity, β-cell function and adiposity in infancy

AIM

Vulnerability to insulin resistance and Type 2 diabetes may originate in early life, but little is known about whether any perinatal biomarkers are predictive of later metabolic health. We sought to assess whether cord blood insulin, insulin-like growth factor (IGF)-I, IGF-II, leptin, adiponectin and ghrelin are associated with metabolic health indicators in infancy.

METHODS

In a prospective singleton birth cohort, we assessed cord blood insulin, IGF-I, IGF-II, leptin, adiponectin and ghrelin concentrations in relation to the homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-β), fasting proinsulin-to-insulin ratio, BMIz-score, and the sum of triceps and subscapular skinfold thickness (an indicator of adiposity) in infants at age 1 year (n = 185).

RESULTS

Adjusting for maternal and infant characteristics, one standard deviation (sd) increase in cord blood adiponectin was associated with an 11.1% (95% confidence interval 1.8-19.5%) decrease in HOMA-β (P = 0.02) and a 13.6% (1.8-26.8%) increase in proinsulin-to-insulin ratio (P = 0.02), indicating worse β-cell function in infants at age 1 year. One sd increase in cord blood insulin was associated with a 0.5 (0.1-1.0) mm increase in skinfold thickness (P = 0.01). One sd increase in cord blood ghrelin was associated with a 0.2 (0.02-0.3) decrease in BMIz-score (P = 0.02) and a 0.5 (0.1-0.9) mm decrease (P = 0.02) in skinfold thickness. Cord blood IGF-I and IGF-II were not associated with the observed metabolic health indicators at age 1 year.

CONCLUSION

The study is the first to show that cord blood adiponectin may be negatively predictive of β-cell function, whereas cord blood ghrelin may be negatively predictive of adiposity in infancy.

Adipose tissue and reproductive health

The understanding of adipose tissue role has evolved from that of a depot energy storage organ to a dynamic endocrine organ. While genetics, sexual phenotype and sex steroids can impact the mass and distribution of adipose tissue, there is a counter-influence of white adipocytes on reproduction. This primarily occurs via the secretion of adipokines, the most studied of which- leptin and adiponectin- are highlighted in this article. Leptin, the "satiety hormone" primarily acts on the hypothalamus via pro-opiomelanocortin (POMC), neuropeptide Y (NPY), and agouti-related peptide (AgRP) neurons to translate acute changes in nutrition and energy expenditure, as well as chronic adipose accumulation into changes in appetite and potentially mediate insulin resistance via shared pathway and notably impacting reproductive health via influence on GnRH secreting neurons. Meanwhile, adiponectin is notable for its action in mediating insulin sensitivity, with receptors found at every level of the reproductive axis. Both have been examined in the context of physiologic and pathologic reproductive conditions. Leptin has been shown to influence puberty, pregnancy, hypothalamic amenorrhea, and lipodystrophy, and with a potential therapeutic role for both metabolic and reproductive health. Adiponectin mediates the relative state of insulin resistance in pregnancy, and has been implicated in conditions such as polycystic ovary syndrome and reproductive malignancies. There are numerous other adipokines, including resistin, visfatin, chemerin and retinol binding protein-4, which may also play roles in reproductive health and disease states. The continued examination of these and other adipokines in both normal reproduction and reproductive pathologies represents an important avenue for continued study. Here, we seek to provide a broad, yet comprehensive overview of many facets of these relationships and highlight areas of consideration for clinicians and future study.

High Dietary ω-6:ω-3 PUFA Ratio Is Positively Associated with Excessive Adiposity and Waist Circumference

OBJECTIVE

The aim of this study was to analyze dietary ω-6:ω-3 polyunsaturated fatty acid (PUFA) ratio and its association with adiposity and serum adiponectin levels in a Mexican population.

METHODS

In this cross-sectional study, individuals with a BMI ≥ 18.5 kg/m2, were classified using four methods to measure adiposity. Parameters of body composition were measured by InBody 3.0. Diet intake was evaluated prospectively using a 3-day written food record. Serum high-molecular weight adiponectin isoform was measured using an ELISA assay. Biochemical and adiposity variables were analyzed by tertiles of dietary ω-6:ω-3 PUFA ratio.

RESULTS

A total of 170 subjects were recruited with a mean age of 36.9 ± 11.8 years. The 73.5% of subjects were women. Subjects in the higher tertile of dietary ω-6:ω-3 PUFA ratio had more adiposity and higher levels of triglycerides, VLDL-c, glucose, insulin and HOMA-IR than those in the first tertile (p < 0.05). Adiponectin levels showed a trend according to dietary ω-6:ω-3 PUFA ratio (p = 0.06). A linear regression model showed that waist circumference, insulin, and HOMA-IR have positive associations with dietary ω-6:ω-3 PUFA ratio.

CONCLUSION

This study suggests that high dietary ω-6:ω-3 PUFA ratio is positively associated with excessive adiposity and worse metabolic profile.

Effect ofBifidobacterium lactisHN019 on inflammatory markers and oxidative stress in subjects with and without the metabolic syndrome

Beneficial effects of probiotics have been reported on body weight, lipid and carbohydrate metabolism, inflammatory state and oxidative stress in healthy subjects and in many metabolic and inflammatory diseases. The aim of this study was to evaluate the effects ofBifidobacterium lactisHN019 on inflammatory state and nitro-oxidative stress in patients with and without the metabolic syndrome (MetS). The usual diets of the thirty-three subjects were supplemented with probiotic milk for 90 d. Inflammatory markers and oxidative measurements were performed. In relation to the baseline values, subjects in both groups showed a decrease in homocysteine (P=0·02 andP=0·03, respectively), hydroperoxides (P=0·02 andP=0·01, respectively) and IL-6 levels (P=0·02). Increases in adiponectin (P=0·04) and nitric oxide metabolites (NOx,P=0·001) levels were only seen in the group with the MetS in relation to the baseline values, whereas only the individuals without the MetS had increases in total radical-trapping antioxidant parameter levels (P=0·002). In conclusion,B. lactisHN019 have several beneficial effects on inflammatory and oxidative biomarkers in healthy subjects and the MetS patients. Patients with the MetS showed a specific improvement in adiponectin and NOx levels, whereas a specific favourable effect was shown in the antioxidant defenses in healthy subjects. If the results obtained in the present study are confirmed, supplementation of fermented milk with probiotics in healthy subjects and patients with the MetS must be further discussed.

Serum vascular adhesion protein-1 is up-regulated in hyperglycemia and is associated with incident diabetes negatively

BACKGROUND/OBJECTIVES

Vascular adhesion protein-1 (VAP-1) can enhance tissue glucose uptake in cell studies and normalize hyperglycemia in animal studies. However, serum VAP-1 concentration (sVAP-1) is higher in subjects with diabetes in cross-sectional studies. In this cohort study, we test our hypothesis that sVAP-1 is increased in prediabetes to counteract hyperglycemia and is associated with incident diabetes negatively.

SUBJECTS/METHODS

From 2006 to 2012, 600 subjects without diabetes from Taiwan Lifestyle Study were included and followed regularly. Diabetes was diagnosed if FPG ≥ 126 mg/dL (7 mmol/L), 2-h plasma glucose (2hPG) during an oral glucose tolerance test (OGTT) ≥ 200 mg/dL (11.1 mmol/L), or hemoglobin A1c (HbA1c) ≥ 6.5%, or if the subject received anti-diabetic medications. Abdominal fat areas were measured by abdominal computed tomography and sVAP-1 was analyzed by ELISA.

RESULTS

sVAP-1 was higher in subjects with prediabetes (p < 0.05) and increased during an OGTT (p < 0.001). Fasting sVAP-1 was associated with the response of sVAP-1 during an OGTT (p < 0.001). Besides, sVAP-1 was associated negatively with body mass index (BMI, r = -0.1449, p = 0.003), waist circumference (r = -0.1425, p = 0.004), abdominal visceral (r = -0.1457, p = 0.003), and subcutaneous (r = -0.1025, p = 0.035) fat areas, and serum high-sensitivity C-reactive protein (hsCRP) concentration (r = -0.2035, p < 0.0001), and positively with plasma adiponectin concentration (r = 0.2086, p < 0.0001), adjusted for age and gender. After 4.7 ± 2.6 years, 73 subjects (12.2%) developed incident diabetes. High sVAP-1 predicted a lower incidence of diabetes, adjusted for age, gender, BMI, family history of diabetes, HbA1c, HOMA2-%B and HOMA2-IR (HR = 0.66, 95% CI = 0.50-0.88, p < 0.01).

CONCLUSIONS

sVAP-1 is increased in response to hyperglycemia. It is associated with obesity and serum hsCRP concentration negatively, and plasma adiponectin concentration positively. Besides, a high sVAP-1 is associated with a lower incidence of diabetes in human.

Adiponectin as a potential therapeutic target for the treatment of restenosis

Restenosis is a pathologic re-narrowing of a coronary artery lesion after mechanical injury. Its pathophysiological mechanisms have not been fully elucidated at present, but are thought to include inflammation, vascular smooth muscle cell (VSMC) proliferation, and matrix remodeling, beginning with insufficient endothelium healing. Restenosis presents with angina symptoms or acute coronary syndromes and lead to a revascularization, either with coronary artery bypass or repeat percutaneous coronary intervention. Some studies have reported that hypoadiponectinemia has been an independent risk factor for the onset of acute coronary syndromes and restenosis. Accumulating evidence shows that low concentrations of adiponectin may be involved in impairing endothelium functions, inflammation, and VSMC proliferation that lead to restenosis. Preclinical studies have proven that adiponectin promotes endothelium healing, effectively inhibits inflammation, and maintains contractile phenotypes of VSMCs, indicating that it may be developed as a new therapeutic target for the treatment of restenosis.

Obesity and High-Fat Diet Induce Distinct Changes in Placental Gene Expression and Pregnancy Outcome

Obese women are at high risk of pregnancy complications, including preeclampsia, miscarriage, preterm birth, stillbirth, and neonatal death. In the current study, we aimed to determine the effects of obesity on pregnancy outcome and placental gene expression in preclinical mouse models of genetic and nutritional obesity. The leptin receptor (LepR) null-reactivatable (LepRloxTB), LepR-deficient (Leprdb/+), and high-fat diet (HFD)-fed mice were assessed for fertility, pregnancy outcome, placental morphology, and placental transcriptome using standard quantitative polymerase chain reaction (qPCR) and qPCR arrays. The restoration of fertility of LepRloxTB was performed by stereotaxic delivery of adeno-associated virus-Cre into the hypothalamic ventral premammillary nucleus. Fertile LepRloxTB females were morbidly obese, whereas the wild-type mice-fed HFD showed only a mild increase in body weight. Approximately 80% of the LepRloxTB females had embryo resorptions (∼40% of the embryos). In HFD mice, the number of resorptions was not different from controls fed a regular diet. Placentas of resorbed embryos from obese mice displayed necrosis and inflammatory infiltrate in the labyrinth and changes in the expression of genes associated with angiogenesis and inflammation (e.g., Vegfa, Hif1a, Nfkbia, Tlr3, Tlr4). In contrast, placentas from embryos of females on HFD showed changes in a different set of genes, mostly associated with cellular growth and response to stress (e.g., Plg, Ang, Igf1, Igfbp1, Fgf2, Tgfb2, Serpinf1). Sexual dimorphism in gene expression was only apparent in placentas from obese LepRloxTB mice. Our findings indicate that an obese environment and HFD have distinct effects on pregnancy outcome and the placental transcriptome.

Relationship among adiponectin, insulin resistance and atherosclerosis in non-diabetic hypertensive patients and healthy adults

Adiponectin, which is secreted specifically by adipose tissue, has been shown to have anti-atherogenic and anti-inflammatory effects and to improve insulin resistance (IR). The aim of this study was to determine the correlations among adiponectin, IR and atherosclerosis in non-diabetic hypertensive patients and healthy volunteers. In this case control study, we collected complete demographic data from and measured several laboratory parameters in all enrolled subjects. The homeostasis model of assessment for insulin resistance (HOMA-IR) was calculated as an insulin sensitivity index. The atherogenic index of plasma (AIP), which is calculated as log (triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C)), was a significant predictor of atherosclerosis and was a better predictor of atherosclerosis than low-density lipoprotein cholesterol (LDL-C). Plasma adiponectin, interleukin (IL)-6, monocyte chemoattractant protein-1 (MCP-1) and matrix metalloprotein-9 (MMP-9) concentrations were determined using enzyme-linked immunosorbent assay (ELISA). All data were analyzed using Statistical Product and Service Solutions for Windows (SPSS) 13.0 software. A total of 309 participants were enrolled in the study. Hypertensive patients with IR (n = 93) displayed significantly higher HOMA-IR values and AIPs and lower adiponectin levels than hypertensive patients without IR (n = 121) and healthy adults (n = 95) (P < 0.05). Furthermore, circulating IL-6, MCP-1 and MMP-9 concentrations differed significantly between hypertensive patients and healthy adults (P < 0.05). Additionally, adiponectin levels were found to be inversely correlated with IL-6, MCP-1, and MMP-9 levels; HOMA-IR values; and AIPs in the clinical study. HOMA-IR values and adiponectin and creatinine (Cr) concentrations remained independently associated with AIPs in all participants after adjustment for confounders via multivariate linear regression. Low adiponectin levels are positively correlated with decreased insulin sensitivity, increased pro-inflammatory cytokine production and worsening atherosclerosis in hypertensive patients and healthy adults.

Obesity as a Disease

Obesity is a complex disease with many causal factors, associated with multiple comorbidities that contribute to significant morbidity and mortality. It is a highly prevalent disease that poses an enormous health and economic burden to society. This article reviews the mechanisms of obesity and its related comorbidities.

C1q/TNF-Related Protein5 (CTRP5) as a Biomarker to Predict Metabolic Syndrome and Each of Its Components

OBJECTIVE

C1q/TNF-related protein5 (CTRP5) is a member of the C1q/tumor necrosis factor α- (TNF-α-) related protein family and has been reported to be associated with the regulation of glucose and lipid metabolism. However, the clinical association between CTRP5 and metabolic syndrome (MetS) has not been reported. The aim of the current study is to investigate the association between CTRP5 and MetS by a cross-sectional study.

METHODS

We performed a cross-sectional study in a Chinese population including 89 controls and 88 MetS individuals. Serum CTRP5 concentrations were determined by ELISA. The relationship between circulating CTRP5 and MetS and insulin resistance (IR) was assessed by Spearman's correlation and multiple stepwise regression analysis.

RESULTS

Circulating CTRP5 concentrations were markedly decreased in MetS individuals relative to normal adults. Overweight/obese individuals (BMI ≥ 25 kg/m²) showed a lower serum CTRP5 level than lean subjects (BMI < 25 kg/m²) in the study population (124.1 (99.12-147.37) vs. 103.9 (79.15-124.25) μg/L; P < 0.01). Circulating CTRP5 was found to be correlated negatively with BMI, FAT%, FBG, WHR, SBP, HbA1c, TG, 2-hour blood glucose after glucose overload (2-hOGTT), FIns, and HOMA-IR and positively with HDL-C (P < 0.05 or P < 0.01). Binary logistic regression revealed that serum CTRP5 levels were associated with MetS. In addition, serum CTRP5 levels gradually decreased with the increase in MetS components.

CONCLUSIONS

Circulating CTRP5 is relative to the elevated risk of MetS in humans and may be in part through the effect of insulin resistance. This trial is registered with ChiCTR-OCS-13003185.

Dietaryα-lactalbumin induced fatty liver by enhancing nuclear liver X receptorαβ/sterol regulatory element-binding protein-1c/PPARγexpression and minimising PPARα/carnitine palmitoyltransferase-1 expression and AMP-activated protein kinaseαphosphorylation associated with atherogenic dyslipidaemia, insulin resistance and oxidative stress in Balb/c mice

The effect and the role played by dietaryα-lactalbumin (α-LAC) on hepatic fat metabolism are yet to be fully elucidated. We reported previously thatα-LAC intake induced atherogenic dyslipidaemia in Balb/c mice. The aim of the present study was to investigate if this atherogenic effect could be due to a possibleα-LAC-induced hepatic steatosis. We examine the ability of dietaryα-LAC to induce liver steatosis, identifying the molecular mechanisms underlying hepatic lipid metabolism in association with the lipid profile, peripheral insulin resistance (IR) and changes in the hepatic oxidative environment. Male Balb/c mice (n6) were fed with diets containing either chow or 14 %α-LAC for 4 weeks. Theα-LAC-fed mice developed abdominal adiposity and IR. Moderate liver steatosis with increased TAG and NEFA contents was correlated with atherogenic dyslipidaemia. There was increased nuclear expression of liver X receptorαβ(LXRαβ), sterol regulatory element-binding protein-1c (SREBP-1c) and PPARγtranscription factors and of the cytosolic enzymes acetyl-CoA carboxylase 1 (ACC1) and fatty acid synthase involved in the hepaticde novolipogenesis. The opposite was found for the nuclear receptor PPARαand the mitochondrial enzyme carnitine palmitoyltransferase-1 (CPT-1), leading to reduced fatty acidβ-oxidation (FAO). These changes were associated with a significant decrease in both p-Thr172-AMP-activated protein kinaseα(AMPKα) (inactivation) and p-Ser79-ACC1 (activation) and with a more oxidative liver environment increasing lipid peroxidation and protein oxidation and reducing GSH:GSSG ratio in theα-LAC-fed mice. In conclusion, 4 weeks of 14 %α-LAC feeding induced liver steatosis associated with atherogenic dyslipidaemia, IR and oxidative stress by enhancing nuclear LXRαβ/SREBP-1c/PPARγexpression and diminishing PPARα/CPT-1 expression and AMPKαphosphorylation shifting the hepatic FAO toward fatty acid synthesis in Balb/c mice.

Synthetic peptides designed to modulate adiponectin assembly improve obesity-related metabolic disorders

BACKGROUND AND PURPOSE

Adiponectin, an adipokine possessing profound insulin-sensitizing and anti-inflammatory properties, is a potent biotherapeutic agent . The trimeric adiponectin subunit assembles into hexameric and functionally important higher molecular weight (HMW) forms, controlled by the endoplasmic reticulum protein 44 (ERp44). Obesity-induced ER stress decreases the HMW form in serum, contributing to the development of insulin resistance and Type 2 diabetes. In this study, a panel of synthetic peptides, designed to target ERp44-adiponectin interactions, were tested for their effects on circulating levels of HMW adiponectin.

EXPERIMENTAL APPROACH

Peptides derived from the ERp44 binding region of adiponectin and immunoglobulin IgM were synthesized with or without a cell-penetrating sequence. Cultures of 3T3-L1 adipocytes were incubated with the peptides for assessing the assembly and secretion of HMW adiponectin. Mice given standard chow or a high-fat diet were treated acutely or chronically, with the peptides to investigate the therapeutic effects on insulin sensitivity and energy metabolism.

RESULTS

The designed peptides interfered with ERp44-adiponectin interactions and modulated adiponectin assembly and release from adipocytes. In particular, IgM-derived peptides facilitated the release of endogenous adiponectin (especially the HMW form) from adipose tissue, enhanced its circulating level and the ratio of HMW-to-total-adiponectin in obese mice. Long-term treatment of mice fed with high-fat diet by IgM-derived peptides reduced the circulating lipid levels and improved insulin sensitivity.

CONCLUSIONS AND IMPLICATIONS

Targeting ERp44-adiponectin interactions with short peptides represents an effective strategy to treat of obesity-related metabolic disorders, such as insulin resistance and Type 2 diabetes.

Positive association between the changes in chemerin and adiponectin levels after weight reduction

PURPOSE

Adiponectin and chemerin have been reported their associations with insulin resistance and chronic inflammation. However, the relationship between adiponectin and chemerin themselves has not been fully elucidated. Therefore, we investigated the effects of changes in adiponectin and chemerin levels after a weight intervention.

MATERIALS AND METHODS

We recruited 136 healthy overweight or obese subjects from 2006 to 2009 and provided all participants lifestyle modification therapy with diet consultations over 16 weeks. We assigned the participants to take orlistat or sibutramine or to a no prescription group. We analyzed the data using paired t-tests, Pearson's partial correlation analysis, and stepwise multiple linear regression analysis.

RESULTS

∆ in chemerin was positively correlated with ∆ in adiponectin (r = 0.29, p < 0.01), and these trends were similar in the insulin-resistant (r = 0.35, p = 0.03) and insulin-sensitive (r = 0.27, p < 0.01) groups. In multiple regression analyses, Δadiponectin, ΔQUICKI (quantitative insulin-sensitivity check index), Δglucose, and ΔDBP were significantly associated with Δchemerin in the insulin-resistant group, and initial chemerin level, ΔQUICKI, ΔBMI (body mass index), and taking orlistat were associated with Δchemerin in the insulin-sensitive group.

CONCLUSIONS

Changes in chemerin levels were positively associated with changes in adiponectin levels. The association between these changes might be related to chemerin's dual inflammatory and anti-inflammatory effects or insulin resistance and insulin sensitivity enhancing effects, depending on the metabolic conditions. Additional studies are needed to clarify the mechanisms that underlie the effects of adiponectin and chemerin.

The polymorphism of rs266729 in adiponectin gene and type 2 diabetes mellitus: A Meta-Analysis

Genome-wide association studies and meta-analyses indicate that the polymorphism of rs266729 in adiponectin gene increases the risk of type 2 diabetes mellitus (T2DM); however, these study methods have not been able to identify the underlying genetic effect on the development of T2DM. A genetic model-free approach was conducted to determine the underlying genetic model of inheritance of T2DM because of rs266729 in adiponectin gene.We searched available studies on the association between the rs266729 in adiponectin gene and T2DM in accordance with the inclusion and exclusion criteria. Based on the information extracted from the studies, generalized odds ratio value (GOR) was used to evaluate whether the rs266729 polymorphism was a risk factor for T2DM. The parameter λ was calculated to estimate the genetic model, which was defined as the quotient of natural logarithm odds ratio of GC to CC divided by the natural logarithm odds ratio of GG to CC. Finally, binary logistic regression analysis was used to calculate the genetic effect of rs266729 on T2DM.Data from 7 studies were included in this meta-analysis. The total number of subjects was 12,323, comprising 5,948 cases and 6,395 controls. Mean (standard deviation) age of cases was 59.50 (11.53), and that of the controls was 53.80 (11.65), whereas the proportion of male was 40.9 and 50.0%, respectively. GOR was 1.13 (1.02, 1.25) and λ was 0.47 (0.29, 0.64). The result of logistic regression indicated that the G allele influenced the development of T2DM in the additive model, whereas the genetic effect was 1.13 (1.06, 1.19). Sources of control populations were the cause of between-study heterogeneity; nonetheless, there was no publication bias among studies.The G allele of rs266729 in adiponectin gene increases the risk of T2DM through an additive genetic model with an effect of 1.13 (1.06, 1.19).

A Functional Interplay between IGF-1 and Adiponectin

A functional relationship is suggested between two well-known protein hormones, insulin-like growth factor 1 (IGF-1) and adiponectin. In the last two decades in fact, different experimental evidence has indicated a non-random link between them. Here, we describe briefly the IGF-1 and adiponectin systems, and we then focus on their putative interplay in relation to several pathological conditions, including obesity, diabetes, insulin resistance, cardiovascular disease, and cancer. Although the existing studies are hardly comparable, they definitely indicate a functional connection between these two protein hormones. In conclusion, the current knowledge strongly encourages further research into the common, as well as novel, mechanisms through which IGF-1 and adiponectin exert their concerted action.

Development of metabolic syndrome in high-sucrose diet fed rats is not associated with decrease in adiponectin levels

PURPOSE

Association of circulating adiponectin levels with metabolic syndrome has been controversial, with studies reporting low as well as high circulating adiponectin levels in metabolic syndrome. Present study aims to examine prospectively the course of circulating adiponectin levels during development of metabolic syndrome in a diet-induced rat model of metabolic syndrome.

METHODS

In a prospective study, eight-week-old male wistar rats were randomized into two groups (n = 24 each). Group A: standard chow diet and group B: high sucrose diet. Body weight, total and high molecular weight (HMW) adiponectin and insulin levels were measured during the study. Oral fat and glucose tolerance tests were done during the study at various time points from weeks 2 to 26. Visceral fat, subcutaneous fat, and adiponectin levels were also measured at week 48 in some of the rats.

RESULTS

Significantly higher total adiponectin levels were found from week 2 to 26 in group B compared to group A (P = <0.05), whereas HMW adiponectin levels were similar in both the groups. Postprandial triglycerides, obesity, insulin resistance, and glucose intolerance were also found to be significantly higher in group B compared to group A during this period (P = <0.05). Total adiponectin levels of week 26 showed significant positive correlation with preceding postprandial triglyceride burden in group B (r = 0.60, P = 0.002).

CONCLUSION

In conclusion, the present study finds that development of metabolic syndrome in high-sucrose diet fed rats is not associated with decrease in circulating adiponectin levels.

THE EFFECT OF SHORT TERM ALPHA LIPOIC ACID ADMINISTRATION ON ADIPONECTIN AND BODY WEIGHT IN TYPE 2 DIABETES MELLITUS PATIENTS

Background

Alpha lipoic acid (ALA) acts as essential co-factor for mitochondrion respiratory enzymes. It has an increasing importance in diabetic neuropathy treatment. Its positive effects on weight gain and metabolic parameters have also been discussed. In this study, we aimed to search for the effect of ALA on weight, appetite, adiponectin and metabolic parameters in type 2 diabetes mellitus patients.

Methods

This study is designed as a randomised, double-blind, placebo controlled, prospective study. 23 type 2 diabetes mellitus patients with peripheral neuropathy (6 normal weight, 17 obese) and 21 normal weight control group were included in the study. Patients were given 600mg/day oral ALA for 6 weeks, added to their routine therapy. Body mass index (BMI), adiponectin, fasting plasma glucose, HbA1C, lipid parameters and CRP levels were tested before and after ALA treatment. Results were evaluated using SPSS 15.0 for Windows.

Results

Adiponectin levels were statistically significantly lower and CRP levels were higher in diabetes group when compared to control group. Although ALA treatment caused a slight weight loss, it was not statistically significant. Appetite scores were decreased in the diabetes group but it did not cause statistically significant weight loss. There was no significant change in metabolic parameters or adiponectin after the treatment.

Conclusions

600mg/dL ALA treatment for 6 weeks did not favor for metabolic parameters in type 2 diabetes patients. This result might be due to the dose or the duration of the treatment, genetic predisposition or dietery habits. Trial of higher doses for long terms might be needed for recovery.