Serum Chemerin Concentrations Associate with Beta-Cell Function, but Not with Insulin Resistance in Individuals with Non-Alcoholic Fatty Liver Disease (NAFLD)

Inter-organ crosstalk during development and progression of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is characterized by tissue-specific insulin resistance and pancreatic β-cell dysfunction, which result from the interplay of local abnormalities within different tissues and systemic dysregulation of tissue crosstalk. The main local mechanisms comprise metabolic (lipid) signalling, altered mitochondrial metabolism with oxidative stress, endoplasmic reticulum stress and local inflammation. While the role of endocrine dysregulation in T2DM pathogenesis is well established, other forms of inter-organ crosstalk deserve closer investigation to better understand the multifactorial transition from normoglycaemia to hyperglycaemia. This narrative Review addresses the impact of certain tissue-specific messenger systems, such as metabolites, peptides and proteins and microRNAs, their secretion patterns and possible alternative transport mechanisms, such as extracellular vesicles (exosomes). The focus is on the effects of these messengers on distant organs during the development of T2DM and progression to its complications. Starting from the adipose tissue as a major organ relevant to T2DM pathophysiology, the discussion is expanded to other key tissues, such as skeletal muscle, liver, the endocrine pancreas and the intestine. Subsequently, this Review also sheds light on the potential of multimarker panels derived from these biomarkers and related multi-omics for the prediction of risk and progression of T2DM, novel diabetes mellitus subtypes and/or endotypes and T2DM-related complications.

The Role of Chemerin in Metabolic and Cardiovascular Disease: A Literature Review of Its Physiology and Pathology from a Nutritional Perspective

Chemerin is a novel adipokine that plays a major role in adipogenesis and lipid metabolism. It also induces inflammation and affects insulin signaling, steroidogenesis and thermogenesis. Consequently, it likely contributes to a variety of metabolic and cardiovascular diseases, including atherosclerosis, diabetes, hypertension and pre-eclampsia. This review describes its origin and receptors, as well as its role in various diseases, and subsequently summarizes how nutrition affects its levels. It concludes that vitamin A, fat, glucose and alcohol generally upregulate chemerin, while omega-3, salt and vitamin D suppress it. Dietary measures rather than drugs acting as chemerin receptor antagonists might become a novel tool to suppress chemerin effects, thereby potentially improving the aforementioned diseases. However, more detailed studies are required to fully understand chemerin regulation.

A healthy lifestyle during adolescence was inversely associated with fatty liver indices in early adulthood: findings from the DONALD cohort study

A healthy lifestyle during adolescence is associated with insulin sensitivity or liver enzyme levels and thus might contribute to the prevention of non-alcoholic fatty liver disease (NAFLD). Therefore, we examined the association between adherence to a hypothesis-based lifestyle score including dietary intake, physical activity, sedentary behaviour, sleep duration and BMI in adolescence and fatty liver indices in early adulthood. Overall, 240 participants of the DOrtmund Nutritional and Anthropometric Longitudinally Designed study completed repeated measurements of lifestyle score factors during adolescence (females: 8·5-15·5 years, males: 9·5-16·5 years). Multivariable linear regression models were used to investigate the association between adolescent lifestyle scores and NAFLD risk (hepatic steatosis index (HSI) and fatty liver index (FLI)) in early adulthood (18-30 years). Participants visited the study centre 4·9 times during adolescence and achieved on average 2·8 (min: 0·6, max: 5) out of five lifestyle score points. Inverse associations were observed between the lifestyle score and fatty liver indices (HSI: ß=-5·8 % (95 % CI -8·3, -3·1), P < 0·0001, FLI: ß=-32·4 % (95 % CI -42·9, -20·0), P < 0·0001) in the overall study population. Sex-stratified analysis confirmed these results in men, while inverse but non-significant associations were observed in women (P > 0·05). A higher lifestyle score was associated with lower HSI and FLI values, suggesting that a healthy lifestyle during adolescence might contribute to NAFLD prevention, predominantly in men. Our findings on repeatedly measured lifestyle scores in adolescents and their association with NAFLD risk in early adulthood warrant confirmation in larger study populations.

A lifestyle pattern during adolescence is associated with cardiovascular risk markers in young adults: results from the DONALD cohort study

Lifestyle score approaches combining individual lifestyle factors, e.g. favourable diet, physical activity or normal body weight, showed inverse associations with cardiovascular disease (CVD) risk. However, research mainly focussed on adult behaviour and is scarce for vulnerable time windows for adult health like adolescence. We investigated associations between an adolescent lifestyle score and CVD risk markers in young adulthood. Overall, we analysed 270 participants of the open DONALD cohort study with 1–6 complete measurements of five lifestyle factors (healthy diet, moderate-to-vigorous physical activity, sedentary behaviour, sleep duration and BMI standard deviation score) during adolescence (females: 8⋅5–15⋅5 years and males: 9⋅5–16⋅5 years). Multivariable linear regression models were used to investigate the prospective association between the adolescent lifestyle score (0–5 points) and CVD risk markers in young adulthood (18–30 years). On average, participants obtained a mean adolescent lifestyle score of 2⋅9 (0–5) points. Inverse associations between the adolescent lifestyle score and waist circumference, waist-to-height ratio and percentage of body fat were observed (4⋅1, 4⋅1 and 9⋅2 % decrease per 1 point increase in adolescent lifestyle score, respectively, P < 0⋅05). For the remaining CVD risk markers (glucose, blood lipids, blood pressure and a proinflammatory score), no associations were observed. A healthy adolescent lifestyle is particularly associated with CVD risk-related favourable anthropometric markers in adulthood. A more comprehensive understanding of lifestyle patterns in the life course might enable earlier, targeted preventive measures to assist vulnerable groups in prevention of chronic diseases.

Relevance of fructose intake in adolescence for fatty liver indices in young adulthood

PURPOSE

To examine the association between fructose intake in adolescence and fatty liver indices (hepatic steatosis index (HSI), fatty liver index (FLI)) in young adulthood.

METHODS

Overall, 246 participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study who had a fasting blood sample in adulthood (18-36 years), at least two 3-day weighed dietary records for calculating fructose intakes and other fructose-containing sugars (total (TS), free (FS), added sugar (AS)) as well as two complete 24-h urine samples for calculating sugar excretion (fructose excretion (FE), fructose + sucrose excretion (FE + SE)) in adolescence (males: 9.5-16.5 years; females: 8.5-15.5 years) were analysed using multivariable linear regression analyses.

RESULTS

On the level of dietary intake, no prospective associations were observed between adolescent fructose intake and both adult fatty liver indices, whereas higher FS intakes were associated with lower levels of HSI (Ptrend = 0.02) and FLI (Ptrend = 0.03). On the urinary excretion level, however, a higher FE (Ptrend = 0.03) and FE + SE (Ptrend = 0.01) in adolescence were prospectively related to higher adult FLI values. No associations were observed between adolescent sugar excretion and adult HSI.

CONCLUSION

The present study does not provide unambiguous support for a detrimental impact of adolescent fructose intake on adult liver health. Nonetheless, further examinations estimating exposure by means of urinary excretion as well as dietary intake levels appear warranted.

Early life factors and their relevance for markers of cardiometabolic risk in early adulthood

BACKGROUND AND AIMS

Early life exposures could be pertinent risk factors of cardiometabolic diseases in adulthood. We assessed the prospective associations of early life factors with markers of cardiometabolic risk among healthy German adults.

METHODS AND RESULTS

We examined 348 term-born DONALD Study participants with measurement of fasting blood at the age of 18-24 years to assess metabolic indices: fatty liver index (FLI), hepatic steatosis index (HSI), pro-inflammatory score and insulin sensitivity (HOMA2-%S). Early life factors (maternal weight in early pregnancy, maternal early pregnancy BMI, gestational weight gain (GWG), maternal age, birth weight and full breastfeeding (>17 weeks)) were assessed at enrolment of the offspring into the study. Multivariable linear regression models were used to analyze associations between early life factors and markers of cardiometabolic risk in early adulthood with adjustment for potential confounders. A higher early pregnancy BMI was related to notably higher levels of offspring FLI, HSI, pro-inflammatory score and a lower HOMA2-%S (all p < 0.0001). Similarly, a higher gestational weight gain was associated with a higher FLI (p = 0.044), HSI (p = 0.016), pro-inflammatory score (p = 0.032) and a lower HOMA2-%S among females (p = 0.034). Full breastfeeding was associated with a lower adult FLI (p = 0.037). A casual mediation analysis showed that these associations were mediated by offspring adult waist circumference (WC).

CONCLUSION

This study suggests that early pregnancy BMI, gestational weight gain, and full breastfeeding are relevant for offspring markers of cardiometabolic risk which seems to be mediated by body composition in young adulthood.

Association of selected adipokines with metabolic syndrome and cardio-metabolic risk factors in young males

The study aimed to investigate association of circulating leptin, adiponectin, chemerin, and omentin-1 with metabolic syndrome (MetS) and cardio-metabolic risk factors in youths. Thirty eight young males were enrolled. Participants underwent anthropometric and blood pressure measures, and fasting blood sampling. Plasma leptin, adiponectin, chemerin, omentin-1 and insulin were measured by ELISA methods. Multiple linear regression models, adjusting for age, MetS traits, C-reactive protein (CRP) and homeostasis model assessment of insulin resistance (HOMA-IR), were applied to determine correlates for each adipokine. Eleven participants meet criteria of MetS. These individuals had higher leptin and chemerin and lower adiponectin plasma concentrations than those without MetS. Plasma leptin and chemerin were positively related, and adiponectin and omentin-1 were inversely related to cardio-metabolic traits. In multivariate models, predictors of leptin were age (β, 0.20, P = 0.01), abdominal obesity (β, 0.24, P = 0.06), raised blood pressure (β, 0.40, P = 0.01), raised triglycerides (β, 0.19, P = 0.01) and CRP (β, 0.31, P = 0.01). Chemerin was associated with abdominal obesity (β, 0.33, P = 0.09) and CRP (β, 0.29, P = 0.04), and adiponectin was associated with raised triglycerides (β, -0.26, P = 0.05), decreased HDL-C (β, -0.28, P = 0.06) and CRP (β, -0.48, P = 0.01). HOMA-IR (β, -0.39, P = 0.09) was the only predictor for omentin. MetS is associated with an altered plasma adipokines profile, with increased leptin and chemerin and decreased adiponectin circulating levels. These findings suggest a beneficial potential of adiponectin and omentin, but a detrimental potential of leptin and chemerin. Further research is needed to lighten the role of adipose tissue-derived adipokines in cardio-metabolic health.

New Biomarkers as Prognostic Factors for Cardiovascular Complications in Type 2 Diabetic Patients

This study was initiated to explore some novel biomarkers like pro-inflammatory markers (chemerin and visfatin) and anti-inflammatory marker (omentin-1) as prognostic factors for cardiovascular complications in type 2 diabetic patients. Forty diabetic patients without cardiovascular disease, 40 diabetic patients with cardiovascular disease and twenty healthy control counterparts were included in this study. Serum chemerin, omentin-1 and visfatin levels were quantified. Receiver operating characteristic curve analysis was done to identify the cut off value for each marker. The mean serum level of chemerin was 57.65 ± 15.69 ng/l in diabetic patients versus 93.97 ± 26.62 ng/l for the cardio-diabetic ones (P < 0.0001). The mean serum level of omentin-1 was 8.77 ± 1.53 ng/ml in diabetic patients versus 1.76 ± 0.96 ng/ml for the cardio-diabetic ones (P < 0.0001). The mean level of visfatin was 1.44 ± 0.71 ug/l in diabetic patients versus 3.92 ± 3.32 ug/l for the cardio-diabetic ones (P < 0.0001). Chemerin and Visfatin levels were significantly enhanced in the cardio-diabetic patients with increasing C-reactive protein (CRP), triglycerides (TG), fasting blood glucose (FBG), micro-albumin and cholesterol. Omentin-1 level was significantly reduced in the cardio-diabetic patients with increasing CRP, TG, FBG, and cholesterol. It was observed that the area under curve for chemerin, omentin-1and visfatin was 0.877, 0.998 and 0.735, respectively. In conclusion, this study evidences that the measuring serum levels of chemerin, omentin-1 and visfatin may help in the prognosis of cardiovascular complications in type 2 diabetic patients.

Association of serum chemerin and inflammatory factors with type 2 diabetes macroangiopathy and waist-to-stature ratio

Chemerin is an adipocytokine that participates in glycolipid metabolism; however, its association with type 2 diabetes (T2DM) with lower extremity macroangiopathy (T2DM-V) has rarely been reported. This study explored the association of chemerin and inflammatory factors with body fat parameters, glucolipid metabolism, and insulin resistance (IR) in T2DM and T2DM-V. Patients were classified into normal glucose regulation (NGR), T2DM, and T2DM-V groups. Serum chemerin, glucolipid metabolic parameters, transforming growth factor (TGF)-β, interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, and fasting insulin levels were measured along with HOMA-IR, body mass index (BMI), and waist-to-stature ratio (WSR). Serum chemerin, TGF-β, IL-6, and MCP-1 levels were significantly higher in T2DM groups than in NGR group, and BMI, WSR, fasting plasma glucose (FPG), 2hPG, glycated hemoglobin (HbA1c), triglycerides (TG), and HOMA-IR were higher in T2DM-V subgroups with moderate or severe lower extremity macroangiopathy than in NGR group, simple T2DM group, and T2DM-V subgroup with mild macroangiopathy. FPG, 2hPG, HbA1c, TG, and HOMA-IR were higher in T2DM-V subgroup with severe macroangiopathy than in T2DM-V with moderate macroangiopathy (p < 0.05). In all groups, serum chemerin levels were positively correlated with BMI, WSR, FPG, 2hPG, HbA1c, fasting insulin, aspartate transaminase, TG, TGF-β, IL-6, and HOMA-IR (p < 0.05) and negatively correlated with high-density lipoprotein cholesterol [HDL-c] (p < 0.05). Multiple stepwise regression analysis showed that 2hPG, HbA1c, and HDL-c were independent predictors of serum chemerin levels (β = -0.768, -0.122, -0.115, and 3.261, respectively; p < 0.01). Collectively, chemerin, factors associated with obesity, pathological and physiological changes in glucolipid metabolism, and inflammatory factors may promote the development of T2DM macroangiopathy.

Associations of circulating chemerin and adiponectin concentrations with hepatic steatosis

OBJECTIVE

Chemerin and adiponectin are adipokines assumed to be involved in the development of metabolic syndrome-related phenotypes like hepatic steatosis. We aimed to evaluate the associations of circulating chemerin and adiponectin concentrations with liver enzymes, liver fat content, and hepatic steatosis in the general population.

METHODS

Data of 3951 subjects from the population-based Study of Health in Pomerania (SHIP-TREND) were used. Hepatic steatosis was assumed when either a hyperechogenic liver (assessed via ultrasound) or a magnetic resonance imaging (MRI)-quantified liver fat content >5% was present. Adjusted sex-specific quantile and logistic regression models were applied to analyze the associations of chemerin and adiponectin with liver enzymes, liver fat content and hepatic steatosis.

RESULTS

The observed associations of chemerin and adiponectin with liver enzymes were very divergent depending on sex, fasting status and the specific enzyme. More consistent results were seen in the analyses of these adipokines in relation to MRI-quantified liver fat content. Here, we observed inverse associations to adiponectin in both sexes as well as a positive (men) or U-shaped (women) association to chemerin. Similarly, the MRI-based definition of hepatic steatosis revealed strongly consistent results: in both sexes, high chemerin concentrations were associated with higher odds of hepatic steatosis, whereas high adiponectin concentrations were associated with lower odds.

CONCLUSION

Our results suggest a role of these adipokines in the pathogenesis of hepatic steatosis independent of metabolic or inflammatory disorders. However, experimental studies are needed to further clarify the underlying mechanisms and the inter-play between adipokine concentrations and hepatic steatosis.

Smoking during pregnancy increases chemerin expression in neonatal tissue

NEW FINDINGS

What is the central question of this study? Is chemerin, an adipokine implicated in obesity, increased in neonates following in utero cigarette smoke exposure. What is the main finding and its importance? Chemerin mRNA expression was increased and chemerin DNA methylation was decreased in babies born to mothers who smoked during pregnancy. These data provide a potential mechanism that may be mediating the increased obesity risk in individuals that are born to mothers who smoked during pregnancy.

ABSTRACT

It has been shown that in utero tobacco exposure increases offspring risk for obesity, but the mechanisms responsible for this increased risk are not well understood. Chemerin is an adipokine that regulates adipocyte differentiation. This chemokine is elevated in obese individuals and with smoke exposure, but its levels have not been measured in neonates exposed to cigarette smoke in utero. We examined chemerin gene expression [n = 31 non-smoker (NS) and 15 smoker (S)] and DNA methylation (n = 28 NS and n = 11 S) in skin collected from babies born to mothers who smoked during pregnancy as compared to non-smoking controls. Quality RNA and DNA were isolated from foreskin tissue following circumcision, and chemerin gene expression and DNA methylation were assessed. Further, in a second cohort, we utilized primary dermal foreskin fibroblasts as a functional measure of adipogenesis in living cells (n = 11 NS and n = 8 S). Cells were stimulated with an adipogenic cocktail, mRNA was isolated from cells after 14 days, and chemerin gene expression assessed via real-time PCR. Chemerin mRNA was elevated in both whole tissue (NS: 2409.20 ± 555.28 counts and S: 2966.72 ± 636.84 counts; P < 0.01) and primary fibroblasts (NS: 1.12 ± <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>0.55</mml:mn> <mml:mspace/> <mml:msup><mml:mn>2</mml:mn> <mml:mrow><mml:mi>Δ</mml:mi> <mml:mi>Δ</mml:mi> <mml:msub><mml:mi>C</mml:mi> <mml:mi>T</mml:mi></mml:msub> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> and S: 2.13 ± <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>1.34</mml:mn> <mml:mspace/> <mml:msup><mml:mn>2</mml:mn> <mml:mrow><mml:mi>Δ</mml:mi> <mml:mi>Δ</mml:mi> <mml:msub><mml:mi>C</mml:mi> <mml:mi>T</mml:mi></mml:msub> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> ; P = 0.04) collected from infants born to smoking mothers. Chemerin DNA methylation was reduced in whole tissue of offspring born to smokers (NS: 4.18 ± 1.28 and S: 3.07 ± 1.31%; P = 0.02), which may contribute to the increased gene expression. Neonates born to mothers who smoke during pregnancy exhibit distinct changes in chemerin gene expression in response to in utero tobacco smoke exposure which are regulated in part by epigenetic alterations.

Inflammation Markers in Type 2 Diabetes and the Metabolic Syndrome in the Pediatric Population

PURPOSE OF REVIEW

Chronic inflammation, adipokines, and hepatokines have been identified as basis of insulin resistance and β cell failure in animal models. We present our current knowledge concerning the potential relationship between these cytokines, inflammation, metabolic syndrome (MetS), and type 2 diabetes mellitus (T2DM) in the pediatric population.

RECENT FINDINGS

Pro-inflammatory cytokines related to insulin resistance and MetS in children are tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-1β, interferon gamma, pigment epithelium-derived factor, chemerin, vaspin, and fetuin A. Anti-inflammatory cytokines associated with insulin resistance and MetS in children are leptin, adiponectin, omentin, fibroblast growth factor (FGF)-21, osteocalcin, and irisin. These anti-inflammatory cytokines are decreased (adiponectin, omentin, and osteocalcin) or increased (leptin, FGF-21, and irisin) in obesity suggesting a resistance state. TNF-α, fetuin A, and FGF-21 are altered in obese children with T2DM suggesting an involvement in β cell failure. These cytokines, adipokines, and hepatokines may be able to predict development of MetS and T2DM and have a potential therapeutic target ameliorating insulin resistance.

Circulating adipokines and mRNA expression in adipose tissue and the placenta in women with gestational diabetes mellitus

Maternal adipose tissue and the placenta secrete various molecules commonly called adipokines such as chemerin, omentin-1, visfatin, adiponectin, and leptin that are important players in the pathogenesis of insulin resistance. Gestational diabetes mellitus (GDM) is defined as a state of glucose intolerance characterized by β-cell dysfunction and insulin resistance. To examine whether circulating adipokines and their mRNA expression in the adipose tissue and the placenta are altered in GDM pregnancy, we compared 15 GDM women [obese (BMI > 30) and non-obese (BMI < 30)] to 23 NGT (normal glucose tolerance) women [obese and non-obese], at the time of the Cesarean section. Circulating chemerin and leptin were higher (p = 0.009 and p = 0.005, respectively) and circulating omentin-1, visfatin, as well as the adiponectin/leptin ratio were lower (p = 0.039, p = 0.007 and p = 0.011, respectively) in GDM-obese compared to NGT-non-obese women. Chemerin and leptin correlated positively with BMI and HOMA-IR and omentin-1 correlated negatively with BMI. Serum TNF-α was significantly elevated in all obese compared to non-obese pregnant women and correlated positively with BMI. Adiponectin levels were reduced -although not significantly- in GDM- and NGT-obese women compared to their non-obese counterparts. Resistin, RPB4 and IL-6 levels did not differ significantly between groups. Chemerin mRNA expression in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) was significantly higher compared to placenta in all women (6-to 24-times, p < 0.05). Chemerin-VAT mRNA expression in GDM-obese tended to be significantly higher compared to NGT-non-obese women (3-times, p = 0.005). Omentin-1 mRNA expression was significantly higher in VAT compared to SAT (50- to 100-times, p < 0.01) and its expression in placenta was negligible in all women. Although, leptin was expressed significantly higher in SAT compared to VAT and the placenta in all women (5- to 46-times, p < 0.05), only its mRNA expression in VAT of obese (GDM and NGT) differed significantly when compared to NGT-non-obese women (3-times higher, p < 0.02). Visfatin mRNA expression was comparable in all tissues. In conclusion, chemerin and leptin are elevated and omentin-1 and visfatin levels are decreased in GDM women complicated by obesity. This finding together with the positive association of chemerin and leptin with markers of insulin resistance, suggests that these adipokines and more especially chemerin and leptin accompanied by their adipose tissue expression could contribute to the increased insulin resistance and low grade inflammation that characterizes GDM-obese women.

Carbohydrates from Sources with a Higher Glycemic Index during Adolescence: Is Evening Rather than Morning Intake Relevant for Risk Markers of Type 2 Diabetes in Young Adulthood?

Background: This study investigated whether glycemic index (GI) or glycemic load (GL) of morning or evening intake and morning or evening carbohydrate intake from low- or higher-GI food sources (low-GI-CHO, higher-GI-CHO) during adolescence are relevant for risk markers of type 2 diabetes in young adulthood. Methods: Analyses included DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study participants who had provided at least two 3-day weighed dietary records (median: 7 records) during adolescence and one blood sample in young adulthood. Using multivariable linear regression analyses, estimated morning and evening GI, GL, low-GI-CHO (GI < 55) and higher-GI-CHO (GI ≥ 55) were related to insulin sensitivity (N = 252), hepatic steatosis index (HSI), fatty liver index (FLI) (both N = 253), and a pro-inflammatory-score (N = 249). Results: Morning intakes during adolescence were not associated with any of the adult risk markers. A higher evening GI during adolescence was related to an increased HSI in young adulthood (p = 0.003). A higher consumption of higher-GI-CHO in the evening was associated with lower insulin sensitivity (p = 0.046) and an increased HSI (p = 0.006), while a higher evening intake of low-GI-CHO was related to a lower HSI (p = 0.009). Evening intakes were not related to FLI or the pro-inflammatory-score (all p > 0.1). Conclusion: Avoidance of large amounts of carbohydrates from higher-GI sources in the evening should be considered in preventive strategies to reduce the risk of type 2 diabetes in adulthood.

Serum omentin-1, vaspin, and apelin levels and central obesity in patients with nonalcoholic fatty liver disease

Background:

Omentin-1, vaspin, and apelin are novel adipokines which closely associate with obesity, nonalcoholic fatty liver disease (NAFLD), and inflammation. The aim of this study was to investigate the circulating levels of omentin-1, vaspin, and apelin in NAFLD patients and to clarify their relationship with biochemical parameters, abdominal obesity, and high sensitive C-reactive protein.

Materials and Methods:

In a case–control study, serum levels of omentin-1, vaspin, and apelin were measured in 41 NAFLD patients and 41 healthy volunteers. The study was performed in the outpatients’ clinic of Imam-Ali Hospital in Zahedan, Iran, during February to July 2015. Fatty liver was confirmed by ultrasonography. The association of the adipokines with lipid profile and anthropometric parameters was assessed using multivariable linear regression models. In this model, those variables that showed P < 0.05 were included in the study.

Results:

NAFLD patients presented a significantly higher apelin levels compared to the controls (P < 0.01), whereas serum omentin-1 and vaspin levels did not differ between two groups (both P > 0.05). Multiple regression analysis showed that the serum levels of apelin and vaspin correlated positively with waist circumference (WC) (P < 0.01 and P < 0.05, respectively) and low-density lipoprotein (P < 0.05 and P < 0.01, respectively) while serum omentin-1 was inversely correlated with WC (P < 0.01) and positively corrected with high-density lipoprotein (P < 0.05).

Conclusion:

The findings showed that among the analyzed adipokines only apelin was different in patients with NAFLD when compared to controls. Considering the multivariate regression analysis, apelin seems be more suitable diagnostic marker in predicting of NAFLD and omentin might be considered as a protective factor in occurrence of NAFLD, particularly in those with central obesity.

Metabolic aspects of adult patients with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease and it encompasses a spectrum from simple steatosis to steatohepatitis, fibrosis, or cirrhosis. The mechanisms involved in the occurrence of NAFLD and its progression are probably due to a metabolic profile expressed within the context of a genetic predisposition and is associated with a higher energy intake. The metabolic syndrome (MS) is a cluster of metabolic alterations associated with an increased risk for the development of cardiovascular diseases and diabetes. NAFLD patients have more than one feature of the MS, and now they are considered the hepatic components of the MS. Several scientific advances in understanding the association between NAFLD and MS have identified insulin resistance (IR) as the key aspect in the pathophysiology of both diseases. In the multi parallel hits theory of NAFLD pathogenesis, IR was described to be central in the predisposition of hepatocytes to be susceptible to other multiple pathogenetic factors. The recent knowledge gained from these advances can be applied clinically in the prevention and management of NAFLD and its associated metabolic changes. The present review analyses the current literature and highlights the new evidence on the metabolic aspects in the adult patients with NAFLD.

Sfrp5 associates with beta-cell function in humans

BACKGROUND

Secreted frizzled-related protein (Sfrp)5 improves insulin sensitivity, but impairs beta-cell function in rodents. However, the relationship between Sfrp5, insulin sensitivity and secretion in humans is currently unclear. Therefore, the aim of the study was to characterize the associations between serum Sfrp5 and indices of insulin sensitivity and beta-cell function from dynamic measurements using oral glucose tolerance tests (OGTT) in humans.

MATERIAL AND METHODS

This study enrolled 194 individuals with nonalcoholic fatty liver disease (NAFLD), who were diagnosed based on ultrasound and liver transaminases and underwent a frequent sampling 75-g OGTT. Fasting serum Sfrp5 was measured by ELISA. Associations were assessed with several indices of insulin sensitivity and beta-cell function derived from glucose, insulin and C-peptide concentrations during the OGTT.

RESULTS

Circulating Sfrp5 associated inversely with the insulinogenic index based on C-peptide (rs = -0·244, P = 0·001), but not with the insulinogenic index based on insulin levels (rs = -0·007, P = 0·926) after adjustment for age, sex and body mass index. Sfrp5 inversely correlated only with QUICKI as a marker of insulin sensitivity in the model adjusted for age and sex (rs = -0·149, P = 0·039). These associations were not influenced by the additional adjustment for hepatic steatosis index.

CONCLUSIONS

The inverse association of serum Sfrp5 with beta-cell function suggests a detrimental role of Sfrp5 for insulin secretion also in humans. The severity of NAFLD does not appear to affect this relationship. The weak association between serum Sfrp5 and insulin sensitivity was partially explained by body mass.