Plasma adiponectin levels are related to obesity, inflammation, blood lipids and insulin in type 2 diabetic and non-diabetic Trinidadians

Plasma Adiponectin and Its Correlation with Carotid Intima-Media Thickness in Obesity and in Type 2 Diabetes and Nonalcoholic Fatty Liver Disease

Methods and Results

The study included 200 Egyptian subjects. They were divided into four equal groups: group 1: obese patients with NAFLD and T2DM (O+/NAFLD+/DM+), group 2: nonobese patients with NAFLD and T2DM (O-/NAFLD+/DM+), group 3: obese nondiabetic patients with NAFLD (O+/NAFLD+/DM-), and group 4: nonobese healthy control subjects. Plasma adiponectin was measured using ELISA (enzyme-linked immunosorbent assay) technique. Ultrasonography was used to diagnose NAFLD. CIMT was assessed using Doppler ultrasonography. Plasma adiponectin was significantly lower and CIMT was significantly higher in O+/NAFLD+/DM+, as compared with O-/NAFLD+/DM+, O+/NAFLD+/DM-, and control subjects (p < 0.001 for all). A significant negative correlation was found between adiponectin and CIMT in obese patients with NAFLD (p < 0.05), but not in patients with NAFLD and T2DM. The significant independent predictors of CIMT were diabetes duration, BMI (body mass index), albumin/creatinine ratio, and cholesterol.

Conclusion

Plasma adiponectin is inversely correlated with CIMT in obese patients with NAFLD, but not in patients with NAFLD and T2DM. Hypoadiponectinemia could be a good indicator of cardiovascular risk in obese patients with NAFLD, with or without T2DM, but not in nonobese patients with NAFLD.

Circulating mir-21 and mir-146a are associated with increased cytokines and CD36 in Algerian obese male participants

BACKGROUND

The microRNAs have come up as crucial mediators of energy balance and metabolic control. CD36 is potential biomarker of obesity and metabolic syndrome. This study investigates the concentration of miR-146a and miR-21 and CD 36 in blood samples of obese and healthy young participants. We assessed the association of mir-146a and mir-21 with inflammatory states in Algerian young participants.

METHODS

Our study included male obese, without co-morbidities (n = 29), and healthy participants (n = 13). miRNA and CD36 expression was measured by real-time RT-PCR, respectively, in serum and blood.

RESULTS

miR-146a and miR-21 concentrations were significantly decreased; however, CD36 expression was increased in obese subjects. Interestingly, miR-146a and miR-21 concentrations were negatively correlated to IL-6, TNF-α, and CD36 in obese participants.

CONCLUSION

We demonstrate that the downregulation of miR-146a and miR-21 was associated with upregulation of inflammatory state and increased CD36 expression in obese participants.

Associations between maternal adiposity and appetite-regulating hormones in human milk are mediated through maternal circulating concentrations and might affect infant outcomes

Background

Appetite-regulating hormones (ARH) in human milk (HM) are suggested to affect infants’ milk intake and possibly infant growth. Maternal adiposity might contribute to higher levels of ARH in HM, either from the mammary gland or from raised circulating levels due to higher adiposity. Counterfactual-based mediation analysis can define indirect and direct effects between HM ARH and maternal and infant factors, and might be an important tool when investigating the mother-milk-infant triad.

Objective

We aim to investigate whether potential associations between (1) maternal adiposity and HM ARH and (2) HM ARH and infant milk intake and growth are mediated through maternal and infant plasma ARH, respectively.

Materials and methods

Maternal and infant anthropometry and body composition, HM and blood samples were collected from 223 mother-infant dyads participating in the Mother, Infant and Lactation Quality study at three postpartum visits from 1 to 8.49 months. Leptin, insulin and adiponectin were analyzed using immunoassays. Mediation analyses using linear mixed-effect models were applied to investigate the direct and indirect effects through maternal and infant plasma hormone concentrations.

Results

A positive association between maternal body-mass-index (BMI) and HM leptin was mediated by maternal plasma leptin by 29% when fixing BMI to < 25 kg/m², and through 51% when fixing BMI to ≥ 25 kg/m² (p_interaction < 0.01). There was no mediated effect through plasma insulin in the association between BMI and HM insulin (p = 0.068). We found negative and positive associations between HM insulin and total milk intake and infant weight, respectively, however, these diminished in mediation analyses with reduced sample sizes.

Conclusion

Our main results suggest that the association between maternal adiposity and HM leptin was mediated through circulating leptin to a stronger degree for mothers with overweight compared to mothers with normal-weight. This indicates that excess maternal adiposity, and the resulting rise of circulating leptin and possible concomitant low-grade inflammation, may be reflected in HM composition.

Clinical trials registry number

NCT03254329.

Body composition and serum levels of matrix metalloproteinase-9, adiponectin and AMP-activated protein kinase in breast cancer survivors

Background:

Available data suggest that obesity is related to changes in the several adipocyte-derived proteins levels, which are involved in cancer recurrence. The purpose of this work was to investigate the correlation between obesity with metalloproteinase-9 (MMP-9), adiponectin and adiponectin and AMP-activated protein kinase (AMPK) levels by comparing serum levels of MMP-9, AMPK in normal weight and obese breast cancer survivors.

Materials and Methods:

In this cross-sectional study, 30 normal weight breast cancer survivors (body mass index [BMI] 18.5-25 kg/m²) and 30 obese breast cancer survivors (BMI ≥30 kg/m²) were investigated. Anthropometric parameters and serum levels of MMP-9, adiponectin, and AMPK were compared between the two groups.

Results:

No differences were detected in the serum levels of MMP-9, adiponectin, and AMPK in obese patients and normal weight patients (P > 0.05). There were no correlations between MMP-9, adiponectin, and AMPK levels with anthropometric measurements in two groups (P > 0.05).

Conclusion:

We found that there was a lack of correlation between obesity measures and serum levels of MMP-9, adiponectin, and AMPK. In breast cancer survivors, it seems that circulating levels of adiponectin, AMPK, and MMP-9 do not change in obesity state.

ApoA-I Mimetic Peptide Reduces Vascular and White Matter Damage After Stroke in Type-2 Diabetic Mice

Diabetes leads to an elevated risk of stroke and worse functional outcome compared to the general population. We investigate whether L-4F, an economical ApoA-I mimetic peptide, reduces neurovascular and white-matter damage in db/db type-2 diabetic (T2DM) stroke mice. L-4F (16 mg/kg, subcutaneously administered initially 2 h after stroke and subsequently daily for 4 days) reduced hemorrhagic transformation, decreased infarct-volume and mortality, and treated mice exhibited increased cerebral arteriole diameter and smooth muscle cell number, decreased blood-brain barrier leakage and white-matter damage in the ischemic brain as well as improved neurological functional outcome after stroke compared with vehicle-control T2DM mice (p < 0.05, n = 11/group). Moreover, administration of L-4F mitigated macrophage infiltration, and reduced the level of proinflammatory mediators tumor necrosis factor alpha (TNFα), high-mobility group box-1 (HMGB-1)/advanced glycation end-product receptor (RAGE) and plasminogen activator inhibitor-1 (PAI-1) in the ischemic brain in T2DM mice (p < 0.05, n = 6/group). In vitro, L-4F treatment did not increase capillary-like tube formation in mouse-brain endothelial cells, but increased primary artery explant cell migration derived from C57BL/6-aorta 1 day after middle cerebral artery occlusion (MCAo), and enhanced neurite-outgrowth after 2 h of oxygen-glucose deprivation and axonal-outgrowth in primary cortical neurons derived from the C57BL/6-embryos subjected to high-glucose condition. This study suggests that early treatment with L-4F provides a potential strategy to reduce neuroinflammation and vascular and white-matter damage in the T2DM stroke population.

The relationship between serum adiponectin levels, cardiometabolic indices and metabolic syndrome in schizophrenia

BACKGROUND

Adiponectin is a hormone secreted by adipose tissues that is thought to influence lipid and glucose metabolism, and the development of metabolic derangements, including metabolic syndrome (MetS), in schizophrenia. We aim to determine the serum adiponectin levels in Chinese patients with schizophrenia, and explore the relationship between adiponectin levels and metabolic parameters, including MetS and its components. We hypothesized that serum adiponectin levels are similar in schizophrenia patients and controls, but decreased amongst patients on atypical antipsychotics.

METHODS

81 patients and 81 controls were recruited. Anthropometric parameters and fasted blood samples for metabolic measurements were obtained. Serum adiponectin levels were measured using Bioplex assays.

RESULTS

There was no difference in median adiponectin levels between schizophrenia patients and controls. Those taking typical antipsychotics alone had lower median adiponectin levels than those on mixed typical and atypical antipsychotics. Serum adiponectin level, controlled for age, gender and body mass index, was positively correlated with high-density lipoprotein cholesterol, and negatively correlated with diastolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels in schizophrenia patients. Patients with MetS had lower median adiponectin levels than those without MetS, and serum adiponectin levels decreased as the number of MetS components increased. After adjusting for variables thought to influence MetS, our logistic regression model did not reveal any significant association between adiponectin levels and MetS in schizophrenia patients.

CONCLUSION

Our findings highlight the need for more studies focusing on serum adiponectin level and its relationship with MetS in schizophrenia, particularly in those taking typical antipsychotics.

The role of adipokines in skeletal muscle inflammation and insulin sensitivity

Background

There is currently an unmet clinical need to develop better pharmacological treatments to improve glucose handling in Type II Diabetes patients with obesity. To this end, determining the effect of obesity-associated adipokines on skeletal muscle insulin sensitivity has emerged as an important area of drug discovery research. This review draws together the data on the functional role of adipokines on skeletal muscle insulin signalling, highlights several understudied novel adipokines and provides a perspective on the direction of future research.

Main body

The adipokines leptin, resistin, visfatin and adiponectin have all been shown to affect skeletal muscle insulin sensitivity by impacting on the activity of components within insulin signalling pathways, affecting GLUT4 translocation and modulating insulin-mediated skeletal muscle glucose uptake. Furthermore, proteomic analysis of the adipose tissue secretome has recently identified several novel adipokines including vaspin, chemerin and pref-1 that are associated with obesity and insulin resistance in humans and functionally impact on insulin signalling pathways. However, predominantly, these functional findings are the result of studies in rodents, with in vitro studies utilising either rat L6 or murine C2C12 myoblasts and/or myotubes. Despite the methodology to isolate and culture human myoblasts and to differentiate them into myotubes being established, the use of human muscle in vitro models for the functional validation of adipokines on skeletal muscle insulin sensitivity is limited.

Conclusion

Understanding the mechanism of action and function of adipokines in mediating insulin sensitivity in skeletal muscle may lead to the development of novel therapeutics for patients with type 2 diabetes. However, to date, studies conducted in human skeletal muscle cells and tissues are limited. Such human in vitro studies should be prioritised in order to reduce the risk of candidate drugs failing in the clinic due to the assumption that rodent skeletal muscle target validation studies will to translate to human.

Cross Talk between Adipose Tissue and Placenta in Obese and Gestational Diabetes Mellitus Pregnancies via Exosomes

Obesity is an important public health issue worldwide, where it is commonly associated with the development of metabolic disorders, especially insulin resistance (IR). Maternal obesity is associated with an increased risk of pregnancy complications, especially gestational diabetes mellitus (GDM). Metabolism is a vital process for energy production and the maintenance of essential cellular functions. Excess energy storage is predominantly regulated by the adipose tissue. Primarily made up of adipocytes, adipose tissue acts as the body's major energy reservoir. The role of adipose tissue, however, is not restricted to a "bag of fat." The adipose tissue is an endocrine organ, secreting various adipokines, enzymes, growth factors, and hormones that take part in glucose and lipid metabolism. In obesity, the greater portion of the adipose tissue comprises fat, and there is increased pro-inflammatory cytokine secretion, macrophage infiltration, and reduced insulin sensitivity. Obesity contributes to systemic IR and its associated metabolic complications. Similar to adipose tissue, the placenta is also an endocrine organ. During pregnancy, the placenta secretes various molecules to maintain pregnancy physiology. In addition, the placenta plays an important role in metabolism and exchange of nutrients between mother and fetus. Inflammation at the placenta may contribute to the severity of maternal IR and her likelihood of developing GDM and may also mediate the adverse consequences of obesity and GDM on the fetus. Interestingly, studies on maternal insulin sensitivity and secretion of placental hormones have not shown a positive correlation between these phenomena. Recently, a great interest in the field of extracellular vesicles (EVs) has been observed in the literature. EVs are produced by a wide range of cells and are present in all biological fluids. EVs are involved in cell-to-cell communication. Recent evidence points to an association between adipose tissue-derived EVs and metabolic syndrome in obesity. In this review, we will discuss the changes in human placenta and adipose tissue in GDM and obesity and summarize the findings regarding the role of adipose tissue and placenta-derived EVs, with an emphasis on exosomes in obesity, and the contribution of obesity to the development of GDM.

Effect of regular exercise training on changes in HbA1c, BMI and VO2max among patients with type 2 diabetes mellitus: an 8-year trial

OBJECTIVE

The effects of regular exercise on the health promotion of patients with type 2 diabetes mellitus (T2DM) have been well documented. The present study investigated the long-term effects of regular exercise training on biological indicators among these patients.

METHODS

In this quasi-experimental trial with pretest-post-test design, 65 patients with T2DM aged 33-69 years (experiment (35), control (30)) participated. After 8 years of conducting the program, the data on 30 patients (experiment (15), control (15)) were entered into analysis. The training program included aerobic exercise three sessions per week, 90 min, 50%-80% VO₂max. Before and after the intervention, the biological indicators (hemoglobin A1c (HbA1c), body mass index (BMI) and VO₂max) were measured. Data were analyzed using multivariate analysis of covariance.

RESULTS

Our long-term exercise training program had a significant effect on HbA1C, BMI and Vo₂max (P<0.05). Compared with patients in the control group, HbA1c was significantly reduced and BMI and VO₂max were significantly improved among the experiment group.

CONCLUSIONS

Long-term regular physical activity training was found to be helpful in improving glycemic control, body composition and cardiovascular fitness among patients with T2DM. Long-term continuous physical activity offsets the deteriorations of biological indicators found in the control group. Further research, with a particular focus on practical and real-world programming, is needed to determine the responsive health outcomes of such long-term programs on the patients.

Effects of basal insulin application on serum visfatin and adiponectin levels in type 2 diabetes

The aim of this study was to investigate the effects of basal insulin application on the serum visfatin and adiponectin (APN) levels of patients with type 2 diabetes mellitus (T2DM). A total of 200 patients with T2DM, who were diagnosed in The Third People's Hospital of Jinan (glycosylated hemoglobin ≥7%), were randomly divided into treatment and control groups. The patients used only oral hypoglycemic drugs and had never received insulin therapy. In the treatment group, basal insulin was administered in combination with the original application of oral hypoglycemic drugs, whereas the control group maintained the original use of oral hypoglycemic drugs or took other oral hypoglycemic agents. The body mass index and fasting blood glucose, postprandial blood glucose, glycosylated hemoglobin, visfatin, APN and blood lipid levels of the patients were examined prior to the treatment and six months later. The drug and insulin doses in the treatment group were adjusted according to the patients' blood glucose, which allowed the fasting and postprandial blood glucose levels to attain the standards. The fasting and postprandial blood glucose levels in the control group also achieved the standards. It was found that the six-month application of basal insulin could significantly decrease the glycosylated hemoglobin and significantly increase the serum APN levels; the serum visfatin levels, however, remained unchanged. The immediate application of basal insulin could facilitate the attainment of glycosylated hemoglobin standards in T2DM and could increase the plasma APN levels, preventing diabetic vascular complications.

Adipokines and biochemical changes in Egyptian obese subjects: possible variation with sex and degree of obesity

The purpose of this study was firstly to evaluate the adipokines and biochemical changes in obese subjects in relation to different grades of obesity and in relation to gender difference (males versus females) and secondly to evaluate the role of TNF-α in obesity. From January 2013 to February 2014, a total number of 120 non-diabetic subjects of both sexes were recruited and randomly selected from Dr. Abd-Elhamid Elsheikh center for physiotherapy and weight control, El-menofia-Egypt. Those subjects were classified according to their sex into two main groups; the female group and the male group. The female group (60 women) was distributed according to BMI into group 1 (15 lean women), group 2 (15 class I obese women), group 3 (15 class II obese women), and group 4 (15 class III obese women). The male group (60 men) was also distributed according to the BMI into group 1 (15 lean men), group 2 (15 class I obese men), group 3 (15 class II obese men), and group 4 (15 class III obese men). All individuals enrolled in the study were submitted to weight and height measurements with subsequent calculation of body mass index. Fasting blood samples were collected from all participants for quantitative determination of blood glucose, serum lipid, TNF-α, leptin, and adiponectin levels. One-way analysis of variance followed by LSD post hoc test was used for comparison of variables. In obese subjects of both sexes, it was found that circulating leptin and TNF-α levels were significantly high (P<0.05) and positively correlated to BMI. In contrast to leptin, adiponectin concentrations were significantly low (P<0.05) and inversely correlated to BMI. Regarding gender difference, although serum leptin and adiponectin levels were higher in women than men, men showed higher atherogenic parameters. We conclude that leptin, TNF-α, and adiponectin were related to both BMI and grades of obesity. Furthermore, TNF-α may play a role in obesity.

Adiponectin serum levels correlate with insulin resistance in type 2 diabetic patients

The adipose tissue is not only an inert storage depot for lipids, but also it secretes a variety of bioactive molecules, known as adipokines, which affect whole-body homeostasis. Adiponectin is the most abundant of these adipocytokines and is known to have a regulatory effect on the metabolism of glucose and lipid. The main objectives of this study were to evaluate the serum levels of adiponectin and to establish a correlation between adiponectin serum levels and the degree of insulin resistance in type 2 diabetic patients. Eighty participants were enrolled in this study; 61 type 2 diabetic patients and 19 apparently healthy subjects. Serum level of adiponectin was measured by enzyme-linked immunosorbent assay (ELISA) for each participant. Data collection sheet was filled with all required information for each participant. Adiponectin level in the diabetic patients (5.05 ± 2.61 μg/ml) was lower than in non-diabetic healthy controls (5.71 ± 2.35 μg/ml). When the results were compared according to gender, diabetic females showed significantly higher adiponectin levels (5.76 ± 2.64 μg/ml) than diabetic males (4.366 ± 2.43 μg/ml, P = 0.035). In addition, female diabetic patients with abdominal obesity (waist circumference (WC) ⩾ 88 cm) had lower adiponectin levels (5.58 ± 2.58 μg/ml) than diabetic females without abdominal obesity (6.96 ± 3.12 μg/ml). The correlation analysis indicated that adiponectin had a significant positive correlation with age (r = −0.450, P < 0.001). In conclusion, female diabetic patients had a statistically significant higher adiponectin level than male diabetic patients which could indicate a gender effect. Adiponectin levels were inversely related to insulin resistance; as patients with abdominal obesity had lower serum levels of adiponectin.

Adiponectin and interleukin-6 in inflammation-associated disease

Numerous lines of evidence implicate a role for adipose tissue in the development of a systemic inflammatory state that contributes to metabolic, cardiovascular, and autoimmune disorders. Serum levels of adiponectin, a cytokine that is mainly produced by adipocytes, are paradoxically decreased in individuals with obesity, type 2 diabetes, and cardiovascular disease compared with healthy individuals. Mounting experimental data have revealed that adiponectin exhibits beneficial effects on energy homeostasis and cardiovascular functions that are attributed to its direct modulation of a proinflammatory factor, interleukin-6. However, some recent studies indicate that adiponectin appears to function as an inducer of proinflammatory factors and the elevated adiponectin level aggravates inflammation response in autoimmune disease. In this review, we focus on the action of adiponectin in chronic inflammation-associated metabolic, cardiovascular, and autoimmune disorders. In particular, we discuss the interaction between adiponectin and interleukin-6 in adipocytes and cardiovascular cells.

Genetic variation in the adiponectin receptor 2 (ADIPOR2) gene is associated with coronary artery disease and increased ADIPOR2 expression in peripheral monocytes

Background

There is debate as to whether the association between C-reactive protein (CRP) and insulin resistance is independent of body fatness, particularly central obesity. Therefore, the association among CRP, insulin resistance and obesity was analyzed in Chinese patients with type 2 diabetes.

Methods

The study included 520 Chinese patients diagnosed with type 2 diabetes with CRP levels not exceeding 10 mg/L. The degree of insulin resistance was determined with the homeostasis model assessment of insulin resistance (HOMA-IR). The CRP levels were categorized into quartiles from the lowest to the highest concentrations (Q1-Q4).

Results

Body mass index (BMI) and waist circumference (WC) were both higher in Q4, Q3 and Q2 than those in Q1. HOMA-IR was higher in Q2, Q3 and Q4 than that in Q1 (Q1 vs Q4, P < 0.001; Q1 vs Q3, P < 0.001; Q1 vs Q2, P = 0.028). Log CRP was significantly correlated with log HOMA-IR (correlation coefficient: 0.230, P < 0.001) and BMI (correlation coefficient: 0.305, P < 0.001) and WC (correlation coefficient: 0.240, P < 0.001) by Spearman correlation analysis. Multiple linear regression analysis adjusting for age, gender and components of metabolic syndrome, log CRP was also independently associated with log HOMA-IR (β coefficient, 0.168; P < 0.001) and WC (β coefficient, 0.131; P = 0.006).

Conclusion

These findings showed that insulin resistance was associated with CRP levels independent of abdominal obesity in Chinese patients with type 2 diabetes, suggesting that abdominal obesity could only partly explain the link between subclinical inflammation and insulin resistance.

Cytokines in the Progression of Pancreatic β-Cell Dysfunction

The dysfunction of pancreatic β-cell and the reduction in β-cell mass are the decisive events in the progression of type 2 diabetes. There is increasing evidence that cytokines play important roles in the procedure of β-cell failure. Cytokines, such as IL-1β, IFN-γ, TNF-α, leptin, resistin, adiponectin, and visfatin, have been shown to diversely regulate pancreatic β-cell function. Recently, islet-derived cytokine PANcreatic DERived factor (PANDER or FAM3B) has also been demonstrated to be a regulator of islet β-cell function. The change in cytokine profile in islet and plasma is associated with pancreatic β-cell dysfunction and apoptosis. In this paper, we summarize and discuss the recent studies on the effects of certain important cytokines on pancreatic β-cell function. The imbalance in deleterious and protective cytokines plays pivotal roles in the development and progression of pancreatic β-cell dysfunction under insulin-resistant conditions.