Metabolic dysfunction-associated fatty liver disease increases the risk of type 2 diabetes mellitus in young Korean adults

AIMS

To investigate the impact of Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD) on the risk of type 2 diabetes mellitus in young Korean adults.

METHODS

Data were sourced from the Korean National Health Insurance Service-Health Screening Cohort, comprising adults aged 20-39 who underwent health examinations between 2009 and 2012. Participants were grouped based on the presence of MAFLD and nonalcoholic fatty liver disease (NAFLD), both individually and in combination. The categorizations included Neither-FLD, NAFLD-only, MAFLD-only, or Both-FLD. Incident diabetes was identified through claims data during the follow-up period.

RESULTS

Among 6,232,656 participants, 676,747 (10.8 %) had MAFLD. During a median follow-up of 9.5 years, 182,291 incident diabetes cases were identified. Multivariate analysis revealed a significantly higher diabetes risk in the MAFLD group compared to those in the Non-MAFLD group (HR = 6.148, 95 % CI, 6.084-6.212). Notably, diabetes incidence was highest in FLI ≥ 60 subgroup with BMI ≥ 23 and metabolic syndrome.

CONCLUSIONS

MAFLD is associated with a 6.1-fold increased diabetes risk in young adults, underscoring the urgent need for early intervention to mitigate this risk.

Cumulative exposure to metabolic syndrome in a national population-based cohort of young adults and sex-specific risk for type 2 diabetes

BACKGROUND

Metabolic syndrome is associated with type 2 diabetes and its prevalence is increasing worldwide in young adults. We aimed to determine whether cumulative exposure to metabolic syndrome is associated with type 2 diabetes risk in young adults.

METHODS

Data of 1,376,540 participants aged 20-39 years without a history of type 2 diabetes and who underwent four annual health check-ups were collected. In this large-scale prospective cohort study, we evaluated the incidence rates and hazard ratios (HRs) of diabetes according to cumulative frequencies of metabolic syndrome over 4 years of consecutive annual health check-ups (burden score 0-4). Subgroup analyses were performed by sex and age.

RESULTS

During 5.18 years of follow-up, 18,155 young adults developed type 2 diabetes. The incidence of type 2 diabetes increased with burden score (P < 0.0001). The multivariable-adjusted HRs for type 2 diabetes were 4.757, 10.511, 18.288, and 31.749 in participants with a burden score of 1 to 4, respectively, compared to those with 0. In subgroup analyses, the risk of incident diabetes was greater in women than men and in the 20-29 years age group than the 30-39 years age group. The HRs were 47.473 in women and 27.852 in men with four burden scores.

CONCLUSION

The risk of type 2 diabetes significantly increased with an increase in the cumulative burden of metabolic syndrome in young adults. Additionally, the association between cumulative burden and diabetes risk was stronger in women and the 20s age group.

Alcohol-induced increase in BMP levels promotes fatty liver disease in male prediabetic stage Otsuka Long-Evans Tokushima Fatty rats

Alcohol consumption exacerbates liver abnormalities in animal models, but whether it increases the severity of liver disease in early diabetic or prediabetic rats is unclear. To investigate the molecular mechanisms underlying alcohol-induced liver steatosis or hepatitis, we used a prediabetic animal model. Otsuka Long-Evans Tokushima Fatty (OLETF) and Long-Evans Tokushima Fatty (LETO) rats were pair-fed with an ethanol-containing liquid diet for 6 weeks. Compared with controls, OLETF and LETO rats displayed more pronounced liver steatosis and higher plasma levels of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamate pyruvate transaminase (SPGT), indicating liver injury. Ethanol-fed LETO (Pd-L-E) rats showed mild liver steatosis and no inflammation compared with ethanol-fed OLETF (Pd-O-E) rats. Although precursor and active SREBP-1 levels in the liver of ethanol-fed OLETF rats significantly increased compared with control diet-fed OLETF rats (Pd-O-C), those of Pd-L-E rats did not. Bone morphogenetic protein (BMP) and TGF-β1 balance in Pd-O-E rats was significantly altered because BMP signaling was upregulated by inducing BMP2, BMP4, BMP7, BMP9, Smad1, and Smad4, whereas TGF-β1, Smad3, and Erk were downregulated. Activation of TGF-β/Smad signaling inhibited BMP2 and BMP9 expression and increased epithelial-mesenchymal transition (EMT) marker levels (Hepcidin, Snail, and Twist) in the liver of LETO rats. Livers of ethanol-fed OLETF rats showed increased levels of vimentin, FSP-1, α-SMA, MMP1, MMP13, and collagen III compared with rats of other groups, whereas EMT marker levels did not change. Thus, BMP exerted anti- and/or pro-fibrotic effects in ethanol-fed rats. Therefore, BMP and TGF-β, two key members of the TGF-β superfamily, play important but diverse roles in liver steatosis in young LETO and OLETF rats.

Inflammatory potential of diet and risk of mortality in normal-weight adults with central obesity

BACKGROUND & AIMS

Inflammatory potential of diet may contribute to poor health outcomes in individuals with metabolic disorders. In a representative sample of the U.S. population, we investigated the association between consuming a pro-inflammatory diet and mortality risk in adults with normal range of body mass index (BMI) but with central obesity.

METHODS

This prospective cohort study included 3521 adults 20-90 years of age with normal BMI who participated in the National Health and Nutrition Examination Survey III, 1988-1994 and did not have a history of cardiovascular disease (CVD) or cancer and did not change their dietary intake in the year preceding baseline measurements. Mortality from all causes, CVD, and cancer was ascertained from the National Death Index. Normal-weight central obesity (NWCO, n = 1777) was defined as those with BMI 18.5 to <25 kg/m2 and waist-to-hip ratio (WHR) ≥0.85 in women and ≥0.90 in men. Severe central obesity was defined as WHR ≥0.92 in women and ≥1.00 in men. The dietary inflammatory index (DII®) was computed based on baseline dietary intake using 24-h dietary recalls, and associations with mortality were estimated using multivariable Cox proportional hazards regression.

RESULTS

In individuals with NWCO, DII score (i.e., more pro-inflammatory diet) was associated with increased risk of CVD mortality (HRT3 vs T1, 1.89 [95% CI, 1.01-3.53], P trend = 0.04; HR 1 SD increase 1.29 [95% CI, 1.06-1.57]). This association was stronger with more severe central obesity (HRT3 vs T1, 2.79 [95% CI, 1.10-7.03], P trend = 0.03; HR 1 SD increase 1.52 [95% CI, 1.05-2.21]). DII score was not associated with increased risk of mortality in normal-weight individuals without central obesity or with risk of cancer mortality in either group.

CONCLUSION

Among individuals in the normal-weight range of BMI, a pro-inflammatory diet assessed by high DII scores was associated with increased risk of CVD mortality in those with central obesity.

Cumulative exposure to impaired fasting glucose and future risk of type 2 diabetes mellitus

AIMS

The status of metabolic abnormalities including impaired fasting glucose (IFG) can change over time, yet little is known about how exposure duration to IFG is related to diabetes risk.

METHODS

Using nationally representative data from the Korean National Health Insurance system, 2,513,127 people who were free of diabetes and who received four consecutive annual health examinations commencing in 2006 or 2007 were followed up at the end of 2016. IFG was defined as fasting blood glucose levels of 100-125 mg/dL. Participants were classified numerically according to the cumulative number of IFG diagnoses.

RESULTS

Over 4 years, 53% of the population participants remained normoglycemic, while 3% had persistent IFG and 44% had intermittent IFG. The risk of type 2 diabetes mellitus (DM) increased gradually with increasing IFG exposure score. Subjects with an IFG exposure score of 2, 3, or 4 had a 3.75- to 9.77-fold increased hazard ratio (HR) for incident diabetes (IFG exposure score 0 reference; score 2, HR 3.75, 95% confidence interval [CI] 3.67-3.83; score 3, HR 6.21, 95% CI 6.08-6.36; score 4, HR 9.77, 95% CI 9.53-10.02).

CONCLUSIONS

Cumulative IFG exposure was associated with a higher risk of type 2 DM in a dose-response fashion.

Combinations of metabolic syndrome components and the risk of type 2 diabetes mellitus: A nationwide cohort study

OBJECTIVE

It remains unclear which specific combinations of metabolic syndrome (MetS) components confer a higher risk of type 2 diabetes mellitus (T2DM). This study examined the relation of each and combinations of MetS components with the risk of T2DM.

METHODS

We studied the records of 19,475,643 adults aged ≥ 20 years with no history of T2DM from the database of the Korean National Health Insurance Service covering 2009 to 2012. The hazard ratios (HRs) and confidence intervals (CIs) of T2DM were estimated using Cox proportional hazards models.

RESULTS

During a median follow-up of 5.13 years, 1,906,963 individuals were diagnosed with T2DM. The multivariable-adjusted HRs for T2DM were 1.86 for MetS, 1.821 for elevated fasting plasma glucose (FPG), 1.484 for elevated triglycerides, 1.415 for reduced high-density lipoprotein (HDL) cholesterol, 1.413 for elevated blood pressure (BP), and 1.17 for abdominal obesity compared with those without. In the combinations of two components excluding elevated FPG, subjects with elevated triglycerides and reduced HDL cholesterol had the highest risk of T2DM (HR 1.71; 95% CI, 1.695-1.725). In three components, the highest risk combination was elevated FPG, elevated triglycerides, and reduced HDL cholesterol (HR 3.342; 95% CI, 3.308-3.376).

CONCLUSIONS

The combination of elevated triglycerides and reduced HDL cholesterol were more strongly associated with an increased risk of T2DM than other combinations except for elevated FPG.

Gemigliptin Inhibits Interleukin-1β-Induced Endothelial-Mesenchymal Transition via Canonical-Bone Morphogenetic Protein Pathway

BACKGROUND

Endothelial-to-mesenchymal transition (EndMT) contributes to inflammatory conditions inducing conversion of endothelial cells (ECs) into activated fibroblasts, promoting fibrotic diseases. Pro-inflammatory cytokine is the most potent inducer of EndMT. We investigated inhibition of interleukin-1β (IL-1β)-induced EndMT by gemigliptin, a dipeptidyl peptidase-IV inhibitor.

METHODS

We exposed human umbilical vein endothelial cells (HUVECs) to 10 ng/mL IL-1β/20 μM gemigliptin and analyzed the expression of endothelial, smooth muscle, mesenchymal, and osteoblastic markers, bone morphogenetic protein (BMP), Smad, and non-Smad signaling pathway proteins.

RESULTS

Morphological changes showed gemigliptin blocked IL-1β-induced EndMT, upregulated EC markers, and downregulated smooth muscle and mesenchymal markers. IL-1β activation of HUVECs is initiated by the BMP/Smad and non-smad BMP signaling pathways. Gemigliptin inhibited IL-1β induction of BMP2 and 7, activin receptor type IA, BMP receptor type IA, and BMP receptor type II. Reversal of IL-1β-mediated inhibition of BMP-induced Smad1/5/8, Smad2, and Smad3 phosphorylation by gemigliptin suggests involvement of the Smad pathway in gemigliptin action. In the non-Smad BMP pathway, gemigliptin treatment significantly increased the deactivation of extracellular regulated protein kinase (ERK), p38, and JNK by IL-1β. Gemigliptin treatment suppressed BMP-2-induced expression of key osteoblastic markers including osterix, runt-related transcription factor 2, and hepcidin during IL-1β-induced EndMT.

CONCLUSION

We demonstrated a novel protective mechanism of gemigliptin against fibrosis by suppressing IL-1β-induced EndMT.

Metabolic profiling of serum and tissue from the rotator interval and anterior capsule in shoulder stiffness: a preliminary study

Background

Using mass spectrometry, we evaluated the metabolic profiles of patients who had rotator cuff tears with shoulder stiffness, or shoulder stiffness only, and compared these with samples from a control group.

Methods

This study enrolled 28 patients, including 10 patients with shoulder stiffness only (group I), nine patients with rotator cuff tear and stiffness (group II), and nine controls selected from patients diagnosed with impingement syndrome or long head of the biceps lesions without evident limitation of joint motion or rotator cuff tears. Serum and tissue from the rotator interval and anterior capsule were collected. In all, 82 samples were analyzed for metabolite profiling using the AbsoluteIDQ™p180 Kit.

Results

Comparison of 186 metabolites revealed that groups I and II had significantly higher concentrations of sphingolipids in serum (SM C24:1; group I = 65.16 μm, group II = 68.07 μm) than controls (55.37 μm, p = 0.005 & 0.015, respectively). Higher concentrations of sphingolipids were also present in the rotator interval tissue (SM C22:3) of groups 1 (0.0197 μm) and 2 (0.0144 μm) than controls (0.0081 μm, p = 0.012 & 0.014, respectively). The concentration of glycerophospholipid (PC aa C30:0) was higher in the anterior capsule tissue of groups I (0.850 μm) and II (1.164 μm) than controls (0.572 μm; p = 0.007) Total cholesterol was positively correlated with sphingolipid concentration in serum (SM C24:1, rho = 0.782, p = 0.008) and rotator interval tissue (SM C22:3, rho = 0.750, p = 0.017). There was no significant difference in the metabolites evaluated in groups I and II.

Conclusion

Metabolic profiling showed that levels of lipid-related metabolites were increased in the anterior capsule tissue and rotator interval tissue of patients with shoulder stiffness. Sphingomyelin (SM C22:3) in the tissue of the rotator interval was positively correlated with the serum level of total cholesterol in patients with shoulder stiffness only. The level of glycerophospholipid (PC30:0) in the anterior capsule was positively correlated with the serum level of total cholesterol in patients who had rotator cuff tear with shoulder stiffness. The results indicate that serum total cholesterol may be related to shoulder stiffness. Future studies are needed to evaluate the role of serum cholesterol in the pathogenesis of shoulder stiffness.

Trial registration

KC12OISI0532. Registered Nov 15, 2012. approval by the Institutional Review Board of Seoul St. Mary’s Hospital, the Catholic University of Korea.

BMI, Weight Change, and Dementia Risk in Patients With New-Onset Type 2 Diabetes: A Nationwide Cohort Study

OBJECTIVE

This study examined the association between baseline BMI, percentage weight change, and the risk of dementia in patients newly diagnosed with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Using the South Korean National Health Insurance Service-National Health Screening Cohort database, we identified 167,876 subjects aged ≥40 years diagnosed with new-onset type 2 diabetes between 2007 and 2012. Their weight changes were monitored for ∼2 years after diagnosis, with follow-up assessments occurring for an average of 3.5 years. The hazard ratios (HRs) and Bonferroni-adjusted 95% CIs of all-cause dementia, Alzheimer disease (AD), and vascular dementia were estimated using multivariable Cox proportional hazards regression models.

RESULTS

We identified 2,563 incident dementia cases during follow-up. Baseline BMI among patients with new-onset type 2 diabetes was inversely associated with the risk of all-cause dementia and AD, independent of confounding variables (P for trend <0.001). The percentage weight change during the 2 years after a diagnosis of type 2 diabetes showed significant U-shaped associations with the risk of all-cause dementia development (P < 0.001); the HRs of the disease increased significantly when weight loss or gain was >10% (1.34 [95% CI 1.11-1.63] and 1.38 [1.08-1.76], respectively). Additionally, weight loss >10% was associated with an increased risk of AD (HR 1.26 [95% CI 1.01-1.59]).

CONCLUSIONS

A lower baseline BMI was associated with increased risks of all-cause dementia and AD in patients with new-onset type 2 diabetes. Weight loss or weight gain after the diagnosis of diabetes was associated with an increased risk of all-cause dementia. Weight loss was associated with an increased risk of AD.

Long-term insulin treatment leads to a change in myosin heavy chain fiber distribution in OLETF rat skeletal muscle

The objective of this study was to investigate molecular and physiological changes in response to long-term insulin glargine treatment in the skeletal muscle of OLETF rats. Male Otsuka Long-Evans Tokushima Fatty (OLETF) and Long-Evans Tokushima Otsuka (LETO) rats aged 24 weeks were randomly allocated to either treatment with insulin for 24 weeks or no treatment, resulting in three groups. Insulin glargine treatment in OLETF rats (OLETF-G) for 24 weeks resulted in changes in blood glucose levels in intraperitoneal glucose tolerance tests compared with age-matched, untreated OLETF rats (OLETF-C), and the area under the curve was significantly decreased for OLETF-G rats compared with OLETF-C rats (P < 0.05). The protein levels of MHC isoforms were altered in gastrocnemius muscle of OLETF rats, and the proportions of myosin heavy chain type I and II fibers were lower and higher, respectively, in OLETF-G compared with OLETF-C rats. Activation of myokines (IL-6, IL-15, FNDC5, and myostatin) in gastrocnemius muscle was significantly inhibited in OLETF-G compared with OLETF-C rats ( P < 0.05). MyoD and myogenin levels were decreased, while IGF-I and GLUT4 levels were increased, in the skeletal muscle of OLETF-G rats ( P < 0.05). Insulin glargine treatment significantly increased the phosphorylation levels of AMPK, SIRT1, and PGC-1α. Together, our results suggested that changes in the distribution of fiber types by insulin glargine could result in downregulation of myokines and muscle regulatory proteins. The effects were likely associated with activation of the AMPK/SIRT1/PGC-1α signaling pathway. Changes in these proteins may at least partly explain the effect of insulin in skeletal muscle of diabetes mellitus.

Alpha-lipoic acid preserves skeletal muscle mass in type 2 diabetic OLETF rats

Background

Increased oxidative stress and impaired antioxidant defense are important mechanisms in the pathogenesis of diabetic myopathy. Alpha-lipoic acid (ALA) has been indicated as a weight-loss treatment in rodents and humans, but studies are limited. In the present study, we aimed to determine the influence of ALA, a potent biological antioxidant, on metabolic and growth processes in diabetic rat skeletal muscle.

Methods

Male 25-week-old type 2 diabetic rats (OLETF) were randomly divided into two groups, a control group (OLETF-C) and an ALA-treated group (OLETF-ALA) supplemented with 100 mg/kg ALA for 8 weeks. Age-matched, healthy, nondiabetic LETO (LETO-C) rats were used as controls.

Results

At 32 weeks of age, body weight was decreased by 6.8%, and the areas under the curve of IP-GTT, fasting glucose, and insulin were less in OLETF-ALA rats compared with OLETF-C rats. ALA significantly preserved muscle mass and enhanced muscle fiber cross-sectional area and fiber frequency percentage in the skeletal muscle of OLETF rats. Although the activation of myoD, myogenin, and myostatin in gastrocnemius muscle was significantly inhibited in OLETF-ALA rats relative to OLETF-C rats, there were no differences in the expression levels of muscle atrogin-1 and MuRF1 between the two groups. ALA treatment significantly increased the levels of phosphorylated 5'-AMPK, SIRT1, and PGC-1α, as well as the levels of phosphorylated AKT, mTOR, and p70S6 kinase in OLETF-ALA rats compared with OLETF-C rats. In contrast, the levels of phosphorylated p38 MAPK, IRS-1, and FOXO1 were decreased in OLETF-ALA rats compared with OLETF-C rats.

Conclusions

ALA treatment preserved mass in the gastrocnemius muscles of OLETF rats. ALA significantly upregulated the AMPK/SIRT1/PGC-1α and AKT/mTOR/p70S6K signaling pathways in OLETF rat skeletal muscle. Therefore, ALA may be a potential therapeutic intervention for skeletal muscle loss in animal models of insulin resistance.

Normal-to-mildly increased albuminuria predicts the risk for diabetic retinopathy in patients with type 2 diabetes

Albuminuria is closely associated with diabetic retinopathy (DR), but the precise role of the albumin-to-creatinine ratio (ACR) in screening for DR remains to be determined. This study aimed to investigate an ACR threshold for predicting DR in patients with type 2 diabetes. A cross-sectional study was conducted on 1,102 type 2 diabetes patients, aged ≥30 years and recruited from the Korea National Health and Nutrition Examination Survey, 2010–2011. Participants were grouped by stage of DR: mild-to-moderate nonproliferative DR (NPDR), severe NPDR, and proliferative diabetic retinopathy (PDR). An early morning spot urine sample was obtained for ACR measurement. ROC curve analysis revealed that the optimal cut-off value of ACR for predicting DR was 2.26 mg/mmol (20 μg/mg). The prevalence of ACR ≥ 2.26 mg/mmol tended to increase with severity of DR. The risk for DR in patients with ACR ≥ 2.26 mg/mmol was higher than in those with ACR < 2.26 mg/mmol. The risk for severe NPDR and PDR also increased at ACR ≥ 2.26 mg/mmol. Normal-to-mildly increased albuminuria (an ACR of 2.26 mg/mmol) may predict the risk for DR development and progression in patients with type 2 diabetes.

High glucose and palmitate increases bone morphogenic protein 4 expression in human endothelial cells

Here, we investigated whether hyperglycemia and/or free fatty acids (palmitate, PAL) aff ect the expression level of bone morphogenic protein 4 (BMP4), a proatherogenic marker, in endothelial cells and the potential role of BMP4 in diabetic vascular complications. To measure BMP4 expression, human umbilical vein endothelial cells (HUVECs) were exposed to high glucose concentrations and/or PAL for 24 or 72 h, and the effects of these treatments on the expression levels of adhesion molecules and reactive oxygen species (ROS) were examined. BMP4 loss-of-function status was achieved via transfection of a BMP4-specific siRNA. High glucose levels increased BMP4 expression in HUVECs in a dose-dependent manner. PAL potentiated such expression. The levels of adhesion molecules and ROS production increased upon treatment with high glucose and/or PAL, but this eff ect was negated when BMP4 was knocked down via siRNA. Signaling of BMP4, a proinflammatory and pro-atherogenic cytokine marker, was increased by hyperglycemia and PAL. BMP4 induced the expression of infl ammatory adhesion molecules and ROS production. Our work suggests that BMP4 plays a role in atherogenesis induced by high glucose levels and/or PAL.

Serum Bone Morphogenic Protein-4 Contributes to Discriminating Coronary Artery Disease Severity

Bone morphogenic protein 4 (BMP-4) is a known pro-inflammatory and pro-atherogenic cytokine. Here, we investigated whether the serum BMP-4 level predicts coronary artery disease (CAD) severity in humans. We measured serum BMP-4 concentrations in 1044 consecutive patients who underwent elective coronary angiography and percutaneous coronary intervention. CAD severity was estimated by the number of diseased vessels showing ≥ 50% diameter stenosis. Among males, the serum BMP-4 level was significantly lower in patients with multivessel disease (MVD) compared with those with single-vessel disease (SVD) (16.3 ± 22.6 vs. 22.0 ± 28.4 pg/mL, P < 0.01). After adjustment for other cardiovascular risk factors, a high serum BMP-4 level was an independent predictor for a decreased risk of MVD (odds ratio, 0.992; 95% confidence interval [CI], 0.985-0.998; P =  .01) and patients in the lower tertile were 1.55-fold more likely to have MVD compared with upper tertile patients. Receiver-operating characteristic curve analysis demonstrated that the serum BMP-4 level had a 54% sensitivity and 54% specificity for predicting MVD (area under the curve [AUC], 56.5%; 95% CI, 51.9-61.0%; P < 0.01). Serum BMP-4 improved the predictive capability of risk factors for MVD (AUC with and without BMP-4: 64.9 and 63.6%, respectively). Considering the likelihood ratio and number of parameters, adding the serum BMP-4 level provided a better-fit model for predicting MVD compared with the model consisting of conventional risk factors (likelihood ratio χ2 = 6.20, P =  .01). However, an association between serum BMP-4 and CAD was not observed in females.Serum BMP-4 levels are independently associated with CAD severity and contribute to discriminating CAD severity in males.

Chronic Alcohol Consumption Results in Greater Damage to the Pancreas Than to the Liver in the Rats

Alcohol consumption increases the risk of type 2 diabetes. However, its effects on prediabetes or early diabetes have not been studied. We investigated endoplasmic reticulum (ER) stress in the pancreas and liver resulting from chronic alcohol consumption in the prediabetes and early stages of diabetes. We separated Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a type-2 diabetic animal model, into two groups based on diabetic stage: prediabetes and early diabetes were defined as occurrence between the ages of 11 to 16 weeks and 17 to 22 weeks, respectively. The experimental group received an ethanol-containing liquid diet for 6 weeks. An intraperitoneal glucose tolerance test was conducted after 16 and 22 weeks for the prediabetic and early diabetes groups, respectively. There were no significant differences in body weight between the control and ethanol groups. Fasting and 120-min glucose levels were lower and higher, respectively, in the ethanol group than in the control group. In prediabetes rats, alcohol induced significant expression of ER stress markers in the pancreas; however, alcohol did not affect the liver. In early diabetes rats, alcohol significantly increased most ER stress-marker levels in both the pancreas and liver. These results indicate that chronic alcohol consumption increased the risk of diabetes in prediabetic and early diabetic OLETF rats; the pancreas was more susceptible to damage than was the liver in the early diabetic stages, and the adaptive and proapoptotic pathway of ER stress may play key roles in the development and progression of diabetes affected by chronic alcohol ingestion.

Intercellular adhesion molecule-1 (ICAM-1, CD54) is increased in adhesive capsulitis

BACKGROUND

The purpose of this study was to investigate the presence of intercellular adhesion molecule-1 (ICAM-1) in shoulders with adhesive capsulitis ("frozen shoulder").

METHODS

Glenohumeral capsular tissue was obtained from twenty-six patients (seventeen with adhesive capsulitis and nine controls), and ICAM-1 was evaluated with use of oligonucleotide arrays, real-time reverse transcription-polymerase chain reaction (RT-PCR), and immunohistochemistry. ICAM-1 was also evaluated in synovial fluid with use of western blotting (six patients with adhesive capsulitis and two controls) and in peripheral blood with use of an enzyme-linked immunosorbent assay (ELISA) (thirty-two patients with adhesive capsulitis, twenty with diabetes mellitus, and fourteen controls). The effect of ICAM-1 treatment on gene expression of cytokines related to inflammation and fibrosis was evaluated in cultured normal human synovial cells.

RESULTS

The level of ICAM-1 was significantly greater in capsular tissue from the glenohumeral joint of patients with adhesive capsulitis compared with controls as measured by oligonucleotide array analysis (0.12 ± 0.01 compared with 0.09 ± 0.00 arbitrary units) (p = 0.001), real-time RT-PCR (1.70 ± 0.19 compared with 0.67 ± 0.24 arbitrary units) (p < 0.05), and immunohistochemical staining. ICAM-1 was also significantly increased in the synovial fluid of patients with adhesive capsulitis (1.70 ± 0.18 arbitrary units) compared with normal controls (0.48 ± 0.17) (p < 0.05) and in serum of patients with adhesive capsulitis (633.22 ± 59.14 ng/mL) and patients with diabetes mellitus (671.25 ± 27.08 ng/mL) compared with controls (359.86 ± 44.29 ng/mL) (p < 0.05). Gene expression of cytokines related to inflammation and fibrosis in synoviocytes cultured in vitro was greater after three days of treatment with ICAM-1 and with ICAM-1 with glucose compared with untreated cells.

CONCLUSIONS

ICAM-1 was increased in patients with adhesive capsulitis, similar to the increase that has been reported in patients with diabetes mellitus.

Changes in serum levels of bone morphogenic protein 4 and inflammatory cytokines after bariatric surgery in severely obese korean patients with type 2 diabetes

Serum bone morphogenic protein- (BMP-) 4 levels are associated with human adiposity. The aim of this study was to investigate changes in serum levels of BMP-4 and inflammatory cytokines after Roux-en-Y gastric bypass (RYGB). Fifty-seven patients with type 2 diabetes underwent RYGB. Serum levels of BMP-4 and various inflammatory markers, including high-sensitivity C-reactive protein (hsCRP), free fatty acids (FFAs), and plasminogen activator inhibitor- (PAI-) 1, were measured before and 12 months after RYGB. Remission was defined as glycated hemoglobin <6.5% for at least 1 year in the absence of medications. Levels of PAI-1, hsCRP, and FFAs were significantly decreased at 1 year after RYGB. BMP-4 levels were also significantly lower at 1 year after RYGB than at baseline (P = 0.024). Of the 57 patients, 40 (70%) had diabetes remission at 1 year after surgery (remission group). Compared with patients in the nonremission group, patients in the remission group had lower PAI-1 levels and smaller visceral fat areas at baseline. There was a difference in the change in the BMP-4 level according to remission status. Our data demonstrate a significant beneficial effect of bariatric surgery on established cardiovascular risk factors and a reduction in chronic nonspecific inflammation after surgery.

Transforming growth factor-β induces epithelial to mesenchymal transition and suppresses the proliferation and transdifferentiation of cultured human pancreatic duct cells

Pancreatic duct cells are considered a potential source of β-cell regeneration, and transforming growth factor-β (TGF-β) has been suggested to perform an important role in these processes, but the underlying mechanism of the signal pathways, especially in humans, remains poorly understood. To evaluate the role of TGF-β1, pancreatic duct cells were isolated from three brain-dead organ donors. Pancreatic cell clusters harvested after islet isolation were dispersed to single cells and cultured in monolayers, then treated with TGF-β1. We analyzed the characteristics of the cultured cells, the TGF-β1 intracellular signaling pathway, the proliferation, and transdifferentiation rates of the duct cells. We also evaluated the genes and protein expression patterns after TGF-β1 treatment. After TGF-β1 treatment, typical morphologic changes representative of EMT were observed and Erk1/2, JNK, and AKT phosphorylation, Ras downstream effectors, were increased. β cell-specific transcription factors including PDX-1, Beta2/NeuroD, Ist-1, and NGN3 were markedly suppressed and the rate of transdifferentiation into β cells was also suppressed. Genomic and proteomic analyses suggested that TGF-β1 induces marked changes in a variety of structural genes and proteins associated with EMT. In conclusion, TGF-β1 induces EMT in cultured human pancreatic duct cells, but suppresses its proliferation and transdifferentiation into β cells. Our results are the first report of TGF-β1 effects for EMT and ductal cell transdifferentiation and proliferation at the protein level in human pancreatic duct cells.

Angiotensin II Inhibits Insulin Binding to Endothelial Cells

BACKGROUND

Insulin-mediated glucose uptake in insulin target tissues is correlated with interstitial insulin concentration, rather than plasma insulin concentration. Therefore, insulin delivery to the interstitium of target tissues is very important, and the endothelium may also play an important role in the development of insulin resistance.

METHODS

After treating bovine aortic endothelial cells with angiotensin II (ATII), we observed the changes in insulin binding capacity and the amounts of insulin receptor (IR) on the cell membranes and in the cytosol.

RESULTS

After treatment of 10(-7)M ATII, insulin binding was decreased progressively, up to 60% at 60 minutes (P<0.05). ATII receptor blocker (eprosartan) dose dependently improved the insulin binding capacity which was reduced by ATII (P<0.05). At 200 µM, eprosartan fully restored insulin binding capacity, althogh it resulted in only a 20% to 30% restoration at the therapeutic concentration. ATII did not affect the total amount of IR, but it did reduce the amount of IR on the plasma membrane and increased that in the cytosol.

CONCLUSION

ATII decreased the insulin binding capacity of the tested cells. ATII did not affect the total amount of IR but did decrease the amount of IR on the plasma membrane. Our data indicate that ATII decreases insulin binding by translocating IR from the plasma membrane to the cytosol. The binding of insulin to IR is important for insulin-induced vasodilation and transendothelial insulin transport. Therefore, ATII may cause insulin resistance through this endothelium-based mechanism.

The relationship between adipokines, metabolic parameters and insulin resistance in patients with metabolic syndrome and type 2 diabetes

This study was designed to investigate the relationship between adipokines in metabolic syndrome and insulin resistance. Sixty male and female subjects with or without metabolic syndrome and type 2 diabetes were included. The homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Compared with lean control subjects, patients with metabolic syndrome and type 2 diabetes had lower circulating levels of total adiponectin and high molecular weight (HMW) adiponectin, and higher levels of leptin and interleukin-6 (IL-6). Total and HMW adiponectin and the adiponectin/leptin (A/L) ratio were negatively correlated with HOMA-IR. After adjusting for age and sex, leptin, IL-6 and tumour necrosis factor-alpha (TNF-alpha) were positively correlated with HOMA-IR. After also adjusting for body mass index, HOMA-IR was found to be independently associated with leptin, A/L ratio and TNF-alpha levels. In conclusion, decreased total adiponectin and HMW adiponectin and increased leptin and IL-6 levels are characteristic of patients with metabolic syndrome and type 2 diabetes.

Hyperglycemia and hyperinsulinemia have additive effects on activation and proliferation of pancreatic stellate cells: possible explanation of islet-specific fibrosis in type 2 diabetes mellitus

Pancreatic islet fibrosis observed in Type 2 diabetes is one of the major factors leading to progressive beta-cell loss and dysfunction. Despite its importance, the mechanism of islet-restricted fibrogenesis associated with pancreatic stellate cell (PSC) activation and proliferation remains to be defined. Therefore, we studied whether the islet-specific environment represented by hyperglycemia and hyperinsulinemia had additive effects on the activation and proliferation of cultured rat PSCs. Cells were stimulated to activate and proliferate with glucose and insulin, either individually or concomitantly. Both stimuli promoted PSC proliferation and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation independently, but an additive effect was also demonstrated. Blockade of ERK signaling by the mitogen-activated protein kinase kinase (MEK) inhibitor, U0126, suppressed both glucose- and insulin-induced ERK 1/2 phosphorylation and PSC proliferation. Glucose and insulin-induced ERK 1/2 phosphorylation also stimulated connective tissue growth factor gene expression. Thus, hyperglycemia and hyperinsulinemia are two crucial mitogenic factors that activate and proliferate PSCs, and the presence of both states will amplify this response.

High glucose increases extracellular matrix production in pancreatic stellate cells by activating the renin-angiotensin system

Pancreatic stellate cells (PSCs) are involved in pancreatic inflammation and fibrosis. Recent studies have shown that blocking the renin-angiotensin system (RAS) attenuates pancreatic inflammation and fibrosis. However, there are few data about the direct effects of high glucose on extracellular matrix (ECM) protein synthesis and angiotensin II (Ang II) induction in PSCs. PSCs were isolated from male Sprague-Dawley rats and cultured in medium containing 5.5 mM (LG group) or 27 mM D-glucose (HG group). Levels of Ang II and transforming growth factor-beta (TGF-beta) in culture media were measured and Ang II-positive cells were counted. We used real-time polymerase chain reaction (PCR) to detect Ang II receptor expression and Western blot analysis for the expression of ECM proteins such as connective-tissue growth factor (CTGF) and collagen type IV. Cells were also treated with an Ang II-receptor antagonist (candesartan, 10 microM) or angiotensin-converting enzyme (ACE) inhibitor (ramiprilat, 100 nM). Thymidine uptake by PSCs increased fourfold with high glucose treatment. Ang II levels and the proportion of Ang II-positive PSCs were significantly increased after 6 h under high-glucose conditions. TGF-beta concentrations also increased significantly with high glucose. After 72 h, the expression of CTGF and collagen type IV proteins in high-glucose cultures increased significantly and this increase was effectively attenuated by the candesartan or the ramiprilat. All together, high glucose induced PSCs proliferation and ECM protein synthesis, and these effects were attenuated by an Ang II-receptor antagonist. The data suggest that pancreatic inflammation and fibrosis aggravated by hyperglycemia, and Ang II play an important role in this pathogenesis.

Proteomic analysis of differential protein expression in response to epidermal growth factor in neonatal porcine pancreatic cell monolayers

We have proposed that porcine neonatal pancreatic cell clusters (NPCCs) may be a useful alternative source of cells for islet transplantation, and that monolayer cultures might provide an opportunity to manipulate the cells before transplantation. In addition we previously identified 10 genes up-regulated by epidermal growth factor (EGF) in cultured porcine NPCC monolayers. We have now analyzed the intracellular signaling pathways activated by EGF and searched for proteins differentially expressed following EGF treatment of the monolayers, using two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). EGF treatment resulted in phosphorylation of both Erk 1/2 and Akt, as well as increased cell proliferation. Five unknown and 13 previously identified proteins were differentially expressed in response to EGF. EGF treatment increased the expression of several structural proteins of epithelial cells, such as cytokeratin 19 and plakoglobin, whereas vimentin, the intermediate filament protein of mesenchymal cells, and non-muscle myosin alkali chain isoform 1, decreased. Heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 factor, which promotes epithelial cell proliferation, and hemoglobin alpha I & II also increased, whereas cyclin A1, immunoglobulin heavy chain, apolipoprotein A1, 5,10-ethylenetetrahydrofolated reductase (5,10-MTHFR), angiotensin-converting enzyme 2 (ACE2), co-lipase II precursor, and NAD+ isocitrate dehydrogenase (NAD+ IDH) alpha chain proteins decreased. Our results show that EGF stimulates proliferation of pancreatic epithelial cells by simultaneously activating the MAPK and PI-3K pathways. HnRNP A2/B1, hemoglobin, cyclin A1, and ACE2 may play roles in the proliferation of epithelial cells in response to EGF.