Endothelial dysfunction, inflammation, and insulin resistance: a focus on subjects at risk for type 2 diabetes

Impact of different types of hypertensive disorders of pregnancy and their duration on incident post-partum risk of diabetes mellitus: Results from the French nationwide study CONCEPTION

AIMS

To evaluate the impact of onset time, duration, and severity of various types of hypertensive disorders of pregnancy (HDP) on the risk of incident DM.

METHODS

We used data from the ongoing French nationwide prospective cohort study CONCEPTION. We included all primiparous women in CONCEPTION who delivered between 2010 and 2018 (n = 2,816,793 women). Follow-up spanned from childbirth to 31 December 2021. HDP and incident DM onset during follow-up were identified using algorithms combining ICD-10 coded diagnoses during hospitalization and/or medication dispensing. We used Cox models to assess the associations between incident DM and preexisting chronic hypertension, gestational hypertension (GH), and various phenotypes of pre-eclampsia.

RESULTS

Pre-eclampsia and GH alone occurred in 2.6 % and 4.6 % of the population, respectively. During follow-up (mean = 4.5 years), 16,670 women had incident DM. The cumulative incidences of DM were 15.8 % and 1.8 % in women who had pre-eclampsia during pregnancy with and without concomitant gestational diabetes, respectively. The risk of DM was higher after HDP (all types) irrespective of gestational diabetes status during pregnancy. In women without gestational diabetes, compared with those who had no HDP, the risk of incident DM was higher in women who had GH (adjusted hazard ratio, aHR = 1.97 [1.81-2.16]), pre-eclampsia (aHR = 2.42 [2.21-2.65]), and preexisting chronic hypertension prior to pregnancy (aHR = 3.35 [3.03-3.70]). Pre-eclampsia duration was significantly associated with a higher risk of DM.

CONCLUSION

Women who experienced an HDP had twice the risk of developing DM. Early blood glucose assessment and blood pressure monitoring should be more widely recommended after HDP diagnosis.

Timing Matters: Effects of Early and Late Estrogen Replacement Therapy on Glucose Metabolism and Vascular Reactivity in Ovariectomized Aged Wistar Rats

Cardiovascular disease incidence increases after menopause due to the loss of estrogen cardioprotective effects. However, there are conflicting data regarding the timing of estrogen therapy (ERT) and its effect on vascular dysfunction associated with impaired glucose metabolism. The aim of this work was to evaluate the effect of early and late ERT on blood glucose/insulin balance and vascular reactivity in aged ovariectomized Wistar rats. Eighteen-month-old female Wistar rats were randomized as follows: (1) sham, (2) 10-week postovariectomy (10 w), (3) 10 w postovariectomy+early estradiol therapy (10 w-early E2), (4) 20-week postovariectomy (20 w), and (5) 20-week postovariectomy+late estradiol therapy (20 w-late E2). Early E2 was administered 3 days after ovariectomy and late therapy after 10 weeks, in both groups. 17β-Estradiol (E2) was administered daily for 10 weeks (5 μg/kg/day). Concentration-response curves to angiotensin II, KCl, and acetylcholine (ACh) were performed. Heart rate (HR), diastolic and systolic blood pressure (DBP and SBP), glucose, insulin, HOMA-IR, and nitric oxide (NO) levels were determined. Higher glucose levels were found in all groups compared to the sham group, except the 20 w-late E2 group. Insulin was increased in all ovariectomized groups compared to sham. The HOMA-IR index showed insulin resistance in all ovariectomized groups, except for the 10 w-early E2 group. The 10 w-early E2 group increased NO levels vs. the 10 w group. After 10 w postovariectomy, the vascular response to KCl and Ach increases, despite early E2 administration. Early and late E2 treatment decreased vascular reactivity to Ang II. At 20-week postovariectomy, DBP increased, even with E2 administration, while SBP and HR remained unchanged. The effects of E2 therapy on blood glucose/insulin balance and vascular reactivity depend on the timing of therapy. Early ERT may provide some protective effects on insulin resistance and vascular function, whereas late ERT may not have the same benefits.

Diabetes health care specific services readiness and availability in Kenya: Implications for Universal Health Coverage

Diabetes is a major cause of morbidity and mortality worldwide yet preventable. Complications of undetected and untreated diabetes result in serious human suffering and disability. It negatively impacts on individual's social economic status threatening economic prosperity. There is a scarcity of data on health system diabetes service readiness and availability in Kenya which necessitated an investigation into the specific availability and readiness of diabetes services. A cross sectional descriptive study was carried out using the Kenya service availability and readiness mapping tool in 598 randomly selected public health facilities in 12 purposively selected counties. Ethical standards outlined in the 1964 Declaration of Helsinki and its later amendments were upheld throughout the study. Health facilities were classified into primary and secondary level facilities prior to statistical analysis using IBM SPSS version 25. Exploratory data analysis techniques were employed to uncover the distribution structure of continuous study variables. For categorical variables, descriptive statistics in terms of proportions, frequency distributions and percentages were used. Of the 598 facilities visited, 83.3% were classified as primary while 16.6% as secondary. A variation in specific diabetes service availability and readiness was depicted in the 12 counties and between primary and secondary level facilities. Human resource for health reported a low mean availability (46%; 95% CI 44%-48%) with any NCDs specialist and nutritionist the least carder available. Basic equipment and diagnostic capacity reported a fairly high mean readiness (73%; 95% CI 71%-75%) and (64%; 95%CI 60%-68%) respectively. Generally, primary health facilities had low diabetic specific service availability and readiness compared to secondary facilities: capacity to cope with diabetes increased as the level of care ascended to higher levels. Significant gaps were identified in overall availability and readiness in both primary and secondary levels facilities particularly in terms of human resource for health specifically nutrition and laboratory profession.

Gender Differences and Cardiometabolic Risk: The Importance of the Risk Factors

Metabolic syndrome (Mets) is a clinical condition characterized by a cluster of major risk factors for cardiovascular disease (CVD) and type 2 diabetes: proatherogenic dyslipidemia, elevated blood pressure, dysglycemia, and abdominal obesity. Each risk factor has an independent effect, but, when aggregated, they become synergistic, doubling the risk of developing cardiovascular diseases and causing a 1.5-fold increase in all-cause mortality. We will highlight gender differences in the epidemiology, etiology, pathophysiology, and clinical expression of the aforementioned Mets components. Moreover, we will discuss gender differences in new biochemical markers of metabolic syndrome and cardiovascular risk.

PPARβ down-regulation is involved in high glucose-induced endothelial injury via acceleration of nitrative stress

Endothelial injury plays a vital role in vascular lesions from diabetes mellitus (DM). Therapeutic targets against endothelial damage may provide critical venues for the treatment of diabetic vascular diseases. Peroxisome proliferator-activated receptor β (PPARβ) is a crucial regulator in DM and its complications. However, the molecular signal mediating the roles of PPARβ in DM-induced endothelial dysfunction is not fully understood. The impaired endothelium-dependent relaxation and destruction of the endothelium structures appeared in high glucose incubated rat aortic rings. A high glucose level significantly decreased the expression of PPARβ and endothelial nitric oxide synthase (eNOS) at the mRNA and protein levels, and reduced the concentration of nitric oxide (NO), which occurred in parallel with an increase in the expression of inducible nitric oxide synthase (iNOS) and 3-nitrotyrosine. The effect of high glucose was inhibited by GW0742, a PPARβ agonist. Both GSK0660 (PPARβ antagonist) and NG-nitro-l-arginine-methyl ester (NOS inhibitor) could reverse the protective effects of GW0742. These results suggest that the activation of nitrative stress may, at least in part, mediate the down-regulation of PPARβ in high glucose-impaired endothelial function in rat aorta. PPARβ-nitrative stress may hold potential in treating vascular complications from DM.

Expression of Circulating MicroRNAs and Myokines and Interactions with Serum Osteopontin in Type 2 Diabetic Patients with Moderate and Poor Glycemic Control: A Biochemical and Molecular Study

BACKGROUND

Cellular miRNAs are expressed in tissue fluids with sufficient amounts and were identified as potential molecular targets for studying the physiological mechanisms and correlations with many human diseases particularly diabetes. However, molecular-based changes among older adults with diabetes mellitus (DM) are rarely fully elucidated.

AIM

This study is aimed at identifying circulating miRNAs, which hold the potential to serve as biomarkers for the immune-inflammatory changes in older T2D patients with moderate and poor glycemic control status. In addition, the association of both myokines and osteopontin (OPN) levels with circulating miRNAs was identified.

METHODS

A total of 80 subjects aged 20-80 years were invited during the period of October 2017-May 2018 to participate in this descriptive cross-sectional study. All subjects were diagnosed with T2D for more than 5 years. Subjects were grouped based on glycemic control (HbA1c values) into two groups: moderate glycemic control (>7-8% HbA1c, no = 30) and poor glycemic control (>8% HbA1c, no = 50), respectively. Diabetic control parameters, fasting blood sugar (FS), HbA1c, fasting insulin (IF), insulin resistance (IR), HOMA-IR, inflammatory cytokines (IL-6, IL-8, IL-18, IL-23, TNF-α, and CRP), osteopontin, and myokines (adropin and irisin) were estimated by colorimetric and immune ELISA assays, respectively. In addition, real-time RT-PCR analysis was performed to evaluate the expression of circulating miRNAs, miR-146a and miR-144, in the serum of all diabetic subjects.

RESULTS

In this study, T2D patients with poor glycemic control showed a significant increase in the serum levels of IL-6, IL-8, IL-18, IL-23, TNF-α, CRP, and OPN and a reduction in the levels of myokines, adropin and irisin, compared to patients with moderate glycemic control. The results obtained are significantly correlated with the severity of diabetes measured by HbA1c, FS, IF, and HOMA-IR. In addition, baseline expression of miR-146a is significantly reduced and miR-144 is significantly increased in T2D patients with poor glycemic control compared to those with moderate glycemic control. In all diabetic groups, the expression of miR-146a and miR-144 is significantly correlated with diabetic controls, inflammatory cytokines, myokines, and serum levels of OPN. Respective of gender, women with T2D showed more significant change in the expressed miRNAs, inflammatory cytokines, OPN, and serum myokine markers compared to men. ROC analysis identified AUC cutoff values of miR-146a, miR-144, adropin, irisin, and OPN expression levels with considerable specificity and sensitivity which recommends the potential use of adropin, irisin, and OPN as diagnostic biomarkers for diabetes with varying glycemic control status.

CONCLUSION

In this study, molecular expression of certain microRNA species, such as miR-146a and miR-144, was identified and significantly associated with parameters of disease severity, HbA1c, inflammatory cytokines, myokines, and serum osteopontin in T2D patients with moderate and poor glycemic control. The AUC cutoff values of circulating miRNAs, miR-146a and miR-144; myokines, adropin and irisin; and serum OPN were significantly identified by ROC analysis which additionally recommends the potential use of these biomarkers, miR-146a, miR-144, adropin, irisin, and OPN, as diagnostic biomarkers with considerable specificity and sensitivity for diabetes in patients with varying glycemic control status.

Nitazoxanide Exerts Immunomodulatory Effects on Peripheral Blood Mononuclear Cells from Type 2 Diabetes Patients

BACKGROUND

Type 2 diabetes (T2D) is a low-grade inflammatory condition with abnormalities in the immune response mediated by T lymphocytes and macrophages. Drug repositioning for immunomodulatory molecules is an attractive proposal for treating T2D. Nitazoxanide (NTZ) is a broad-spectrum drug with promising immunomodulatory effects. Thus, we investigated the immunomodulatory effect of NTZ on peripheral blood mononuclear cells (PBMCs) from patients with T2D.

METHODS

Fifty patients with T2D were selected, and the proliferative response of T lymphocytes and the M1/M2 ratio of macrophages post cell culture were evaluated by flow cytometry, as well as measuring the concentration of cytokines by ELISA and the relative expression of microRNAs (miRNAs) related to the immune response by real-time PCR.

RESULTS

NTZ exerts an inhibitory effect on the cell proliferation of T lymphocytes stimulated with anti-CD3 and anti-CD28 antibodies without modifying cell viability, and significant decreases in the supernatant concentrations of interleukin (IL)-1β, IL-2, IL-6, IL-10, and IL-12. Furthermore, NTZ negatively regulates the relative expression of miR-155-5p without changes in miR-146a-5p. The M1/M2 ratio of monocytes/macrophages decreased the M1 and increased the M2 subpopulation by NTZ.

CONCLUSIONS

Our results suggest that NTZ exerts immunomodulatory effects on PBMCs from T2D patients, and shows potential alternative therapeutic benefits.

A Critical Review of the Biochemical Mechanisms and Epigenetic Modifications in HIV- and Antiretroviral-Induced Metabolic Syndrome

Metabolic syndrome (MetS) is a non-communicable disease characterised by a cluster of metabolic irregularities. Alarmingly, the prevalence of MetS in people living with Human Immunodeficiency Virus (HIV) and antiretroviral (ARV) usage is increasing rapidly. This study aimed to look at biochemical mechanisms and epigenetic modifications associated with HIV, ARVs, and MetS. More specifically, emphasis was placed on mitochondrial dysfunction, insulin resistance, inflammation, lipodystrophy, and dyslipidaemia. We found that mitochondrial dysfunction was the most common mechanism that induced metabolic complications. Our findings suggest that protease inhibitors (PIs) are more commonly implicated in MetS-related effects than other classes of ARVs. Furthermore, we highlight epigenetic studies linking HIV and ARV usage to MetS and stress the need for more studies, as the current literature remains limited despite the advancement in and popularity of epigenetics.

Dipstick proteinuria and risk of type 2 diabetes mellitus: a nationwide population-based cohort study

Background

Proteinuria has been recognized as a marker of systemic inflammation and endothelial dysfunction associated with insulin resistance and β-cell impairment, which can contribute to the development of type 2 diabetes mellitus (T2DM). However, it is unknown whether the dipstick proteinuria test has a predictive value for new-onset T2DM.

Methods

This retrospective cohort study analyzed 239,287 non-diabetic participants who participated in the Korean nationwide health screening program in 2009–2010. Proteinuria was determined by the urine dipstick test at the baseline health screening. We performed multivariate Cox proportional regression analyses for the development of new-onset T2DM. Follow-up was performed until December 2015.

Results

During the mean follow-up period of 5.73 years, 22,215 participants were diagnosed with new-onset T2DM. The presence of proteinuria was significantly associated with an increased risk of T2DM (adjusted hazard ratio: 1.19, 95% confidence interval: 1.10, 1.29). There was a positive dose–response relationship between the degree of dipstick proteinuria and T2DM risk. This significant association between proteinuria and T2DM risk was consistent regardless of the fasting glucose level at baseline.

Conclusions

Dipstick proteinuria is a significant risk factor for new-onset T2DM. Therefore, proteinuria might be a useful biomarker to identify those at a high risk for developing T2DM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02934-y.

Effects of external counter-pulsation on endothelial function assessed by peripheral artery tonometry, levels of glycaemia and metabolic markers in individuals with type 2 diabetes mellitus

BACKGROUND AND AIMS

External counter-pulsation (ECP) generates sheer stress thereby improving endothelial function and anginal symptoms in coronary artery disease. Endothelial dysfunction is also involved in the pathogenesis of T2DM. The aim of this pilot study was to investigate the use of ECP at different doses in improving endothelial function and glycaemic markers in T2DM.

METHODS

This prospective study involved 46 subjects with T2DM randomly assigned to receive 35 sessions of ECP at different regimens (0.5 h versus 1 h) and duration (7 versus 12 weeks). Endothelial function was evaluated by reactive hyperaemia index (RHI) via peripheral arterial tonometry at the start, midpoint and end of study. Other secondary outcomes included fasting glucose, HOMA-IR, HbA1c, blood pressure, lipid profile, weight and vibration sense.

RESULTS

There was no change in RHI across all 3 regimens of ECP individually or collectively at the end of the study (ΔRHI +0.01%, p = 0.458). Glycaemic markers also remained unchanged at endpoint. Subgroup analysis showed an improvement in RHI (ΔRHI +20.6%, p = 0.0178) in subjects with more severe endothelial dysfunction at baseline.

CONCLUSION

ECP did not show a beneficial effect on endothelial function or glycemic control in this South-East Asian population with T2DM at any of the three regimens. This may partly be explained by less severe endothelial dysfunction and less insulin resistance in our population at baseline.

An update on metabolic syndrome: Metabolic risk markers and adipokines in the development of metabolic syndrome

Metabolic syndrome is a collection of physiological and biochemical abnormalities about 20-25% of adult population in developing countries is suffering from metabolic syndrome. Previous research demonstrated that adipose tissue plays an important role in energy regulation via endocrine, paracrine and autocrine signals as results of obesity due to accumulation of adipose tissue to excess that by time affects negatively both physical and psychological health and well being, it has been found that adipose tissues produces a variety of factors known as "adipokines" which play a key role in the development and progression of the disease and also hypothesized that adipokines are a possible link between obesity and the other risk components of the Metabolic syndrome. Many of the adipokines exert multiple actions in a variety of cellular processes leading to a complex array of abnormal characteristic of Metabolic syndrome. Abnormal production of these adipokines by expanded visceral fat during Adiposity contributes to a pro-inflammatory state. Increasing evidence suggests that aberrant production/release of adipokine from adipocyte i.e. adiponectin, leptin and resistin etc, may contribute to the health problems associated with Adiposity such as dyslipidemia, insulin resistance and atherosclerosis. This study conclusively have shown a significant role of adipokines secreted by adipose tissue and various metabolic risk markers play a important role in the development of Metabolic syndrome.

The "A to Z" of Managing Type 2 Diabetes in Culturally Diverse Populations

Type 2 diabetes affects racial/ethnic minorities at an alarming rate in the US and in many countries around the world. The quality of health care provided to these groups is often suboptimal, resulting in worse patient-related outcomes when compared to those in mainstream populations. Understanding the complex biological elements that influence the development and course of the disease in high-risk populations is extremely important but often insufficient to implement effective prevention and treatment plans. Multiple factors must be addressed in routine diabetes clinical care. This paper discusses various key factors, organized in alphabetical order. These are acculturation, biology, clinician's cultural awareness, depression and diabetes-specific emotional distress, educational level, fears, group integration, health literacy, intimacy and sexual dysfunction, judging, knowledge of the disease, language, medication adherence, nutritional preferences, other forms of medicine (alternative), perception of body image, quality of life, religion and faith, socio-economic status, technology, unconscious bias, vulnerable groups, asking why?, exercise, "you are in charge" and zip it! Considering these factors in the development of type 2 diabetes prevention and treatment programs will help improve diabetes-related outcomes in culturally diverse populations and reduce health care disparities.

Persistence of abnormalities in white matter in children with type 1 diabetes

AIMS/HYPOTHESIS

Prior studies suggest white matter growth is reduced and white matter microstructure is altered in the brains of young children with type 1 diabetes when compared with brains of non-diabetic children, due in part to adverse effects of hyperglycaemia. This longitudinal observational study examines whether dysglycaemia alters the developmental trajectory of white matter microstructure over time in young children with type 1 diabetes.

METHODS

One hundred and eighteen children, aged 4 to <10 years old with type 1 diabetes and 58 age-matched, non-diabetic children were studied at baseline and 18 months, at five Diabetes Research in Children Network clinical centres. We analysed longitudinal trajectories of white matter using diffusion tensor imaging. Continuous glucose monitoring profiles and HbA_1c levels were obtained every 3 months.

RESULTS

Axial diffusivity was lower in children with diabetes at baseline (p = 0.022) and at 18 months (p = 0.015), indicating that differences in white matter microstructure persist over time in children with diabetes. Within the diabetes group, lower exposure to hyperglycaemia, averaged over the time since diagnosis, was associated with higher fractional anisotropy (p = 0.037). Fractional anisotropy was positively correlated with performance (p < 0.002) and full-scale IQ (p < 0.02).

CONCLUSIONS/INTERPRETATION

These results suggest that hyperglycaemia is associated with altered white matter development, which may contribute to the mild cognitive deficits in this population.

Biochemical investigation of gender-specific association between insulin resistance and inflammatory biomarkers in types 2 diabetic patients

Inflammatory mediators play a key role in the pathogenesis of type 2 diabetes mellitus (T2DM) and development of insulin resistance (IR). The purpose of the present study was to investigate the gender-specific association between serum levels of inflammatory biomarkers and development of IR in type 2 diabetic patients. We recruited 90 study participants and collected their blood samples to measure the serum level of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), insulin and glucose. We found that the serum levels of IL-6 (< 0.0001), TNF-α (< 0.0001) and CRP (< 0.0001) in type 2 diabetic patients were significantly high as compared to control participants. Moreover, we also found that in female diabetic patients, a significant association was observed between the elevated levels of IL-6 (r = 0.8819, R² = 0.7778), TNF-α (r = 0.9833, R² = 0.9669) and CRP (r = 0.9529, R² = 0.9080) and increased risk of developing IR when compared with that of the serum levels of IL-6 (r = 0.7977, R² = 0.6364), TNF-α (r = 0.9445, R² = 0.8920) and CRP (r = 0.9051, R² = 0.8192) of male diabetic patients. Additionally, we also found that the Body mass index (BMI) of female diabetic patients was strongly correlated (r = 0.9694, R² = 0.9398) with the increased incidence of IR as compared to that of the BMI (r = 0.9188, R² = 0.8442) of male diabetic patients. The key findings of present study exhibit that gender differences significantly influence the association of inflammatory biomarkers with the development of IR in T2DM.

The Gut Microbiota and Alzheimer's Disease

The gut microbiota comprises a complex community of microorganism species that resides in our gastrointestinal ecosystem and whose alterations influence not only various gut disorders but also central nervous system disorders such as Alzheimer's disease (AD). AD, the most common form of dementia, is a neurodegenerative disorder associated with impaired cognition and cerebral accumulation of amyloid-β peptides (Aβ). Most notably, the microbiota-gut-brain axis is a bidirectional communication system that is not fully understood, but includes neural, immune, endocrine, and metabolic pathways. Studies in germ-free animals and in animals exposed to pathogenic microbial infections, antibiotics, probiotics, or fecal microbiota transplantation suggest a role for the gut microbiota in host cognition or AD-related pathogenesis. The increased permeability of the gut and blood-brain barrier induced by microbiota dysbiosis may mediate or affect AD pathogenesis and other neurodegenerative disorders, especially those associated with aging. In addition, bacteria populating the gut microbiota can secrete large amounts of amyloids and lipopolysaccharides, which might contribute to the modulation of signaling pathways and the production of proinflammatory cytokines associated with the pathogenesis of AD. Moreover, imbalances in the gut microbiota can induce inflammation that is associated with the pathogenesis of obesity, type 2 diabetes mellitus, and AD. The purpose of this review is to summarize and discuss the current findings that may elucidate the role of the gut microbiota in the development of AD. Understanding the underlying mechanisms may provide new insights into novel therapeutic strategies for AD.

Expression of intercellular adhesion molecule-1 in umbilical vascular of pregnant women with gestational diabetes mellitus and the clinical significance

The purpose of this study was to investigate the expression of intercellular adhesion molecule-1 (ICAM-1) in umbilical vascular of pregnant women with gestational diabetes mellitus (GDM) and the clinical significance. A total of 103 pregnant women with GDM were selected in the First Hospital of Lanzhou University and the Second Affiliated Hospital of Xi'an Jiaotong University from January 2016 to December 2016 as GDM group. At the same time, 106 normal pregnant women were selected as control group. i) General information of the two groups of pregnant women including age, gestational age, gravida, parity, BMI, systolic blood pressure and diastolic blood pressure were compared; ii) the laboratory indicators of the two groups of pregnant women including fasting blood glucose, glycosylated hemoglobin (HbA1c), umbilical cord arterial pH, partial pressure of oxygen (pO₂) and carbon dioxide (pCO₂) in umbilical artery were compared; iii) expression of ICAM-1 in umbilical vascular was detected by immunohistochemistry; iv) expression levels of ICAM-1 in umbilical vascular of the two groups of patients were compared. i) There was no significant difference in the age, smoking, gestational age, gravida, parity, BMI, systolic blood pressure and diastolic blood pressure between the two groups (p>0.05); ii) no significant differences in HbA1c, umbilical cord arterial pH, pO₂ and pCO₂ were found between the groups (p>0.05); iii) ICAM-1 was expressed in umbilical vessels of both groups of pregant women; iv) no significant differences in expression levels of ICAM-1 in umbilical artery and umbilical vein endothelial cells were found between the groups (p>0.05). Therefore, GDM patients with good blood glucose control have no umbilical cord endothelial cell damage.

DPP-4 inhibition protects human umbilical vein endothelial cells from hypoxia-induced vascular barrier impairment

Dipeptidyl peptidase-4 (DPP-4) inhibitors are relatively new class of anti-diabetic drugs. Some protective effects of DPP-4 on cardiovascular disease have been described independently from glucose-lowering effect. However, the detailed mechanisms by which DPP-4 inhibitors exert on endothelial cells remain elusive. The purpose of this research was to determine the effects of DPP-4 inhibitor on endothelial barrier function. Human umbilical vein endothelial cells (HUVECs) were cultured and exposed to hypoxia in the presence or absence of Diprotin A, a DPP-4 inhibitor. Immunocytochemistry of vascular endothelial (VE-) cadherin showed that jagged VE-cadherin staining pattern induced by hypoxia was restored by treatment with Diprotin A. The increased level of cleaved β-catenin in response to hypoxia was significantly attenuated by Diprotin A, suggesting that DPP-4 inhibition protects endothelial adherens junctions from hypoxia. Subsequently, we found that Diprotin A inhibited hypoxia-induced translocation of NF-κB from cytoplasm to nucleus through decreasing TNF-α expression level. Furthermore, the tube formation assay showed that Diprotin A significantly restored hypoxia-induced decrease in number of tubes by HUVECs. These results suggest that DPP-4 inhibitior protects HUVECs from hypoxia-induced barrier impairment.

SIRT3 Deficiency Induces Endothelial Insulin Resistance and Blunts Endothelial-Dependent Vasorelaxation in Mice and Human with Obesity

Recent evidence implicates the critical role of Sirtuin 3 (SIRT3) in the development of many metabolic diseases, but the contribution of SIRT3 to vascular homeostasis remains largely unknown. The aim of this study was to investigate the role of SIRT3 in endothelial insulin resistance and vascular dysfunction in obesity. We found an impaired insulin-induced mesenteric vasorelaxation and concomitant reduced vascular SIRT3 expression in morbid obese human subjects compared with the non-obese subjects. Downregulation of SIRT3 in cultured human endothelial cells increased mitochondrial reactive oxygen species (mtROS) and impaired insulin signaling as evidenced by decreased phosphorylation of Akt and endothelial nitric oxide synthase and subsequent reduced nitric oxide (NO) release. In addition, obese mice induced by 24-week high-fat diet (HFD) displayed an impaired endothelium-dependent vasorelaxation to both insulin and acetylcholine, which was further exacerbated by the gene deletion of Sirt3. Scavenging of mtROS not only restored insulin-stimulated NO production in SIRT3 knockdown cells, but also improved insulin-induced vasorelaxation in SIRT3 knockout mice fed with HFD. Taken together, our findings suggest that SIRT3 positively regulates endothelial insulin sensitivity and show that SIRT3 deficiency and resultant increased mtROS contribute to vascular dysfunction in obesity.

Insulin Therapy, Glycemic Control, and Cardiovascular Risk Factors in Young Latin Americans with Type 2 Diabetes Mellitus

BACKGROUND

Type 2 diabetes has been linked to an increased risk of cardiovascular (CV) disease, but this risk has not been well documented in young patients, especially of Latin American descent. Also, the potential CV benefits of insulin therapy have not been evaluated in young patients with type 2 diabetes. The objectives of this study were to determine any gender-related difference in the presence of CV risk factors in young Latin Americans with poorly controlled type 2 diabetes and the effect of intensive insulin therapy on these CV risk factors.

METHODS AND RESULTS

Fifty-seven Latin American patients with type 2 diabetes between the ages 18 and 45 years were evaluated at baseline. All women were premenopausal and had regular menstrual periods. The mean body mass index (BMI) was > 30 kg/m2 in both genders. Percent body fat, percent hemoglobin A1c, and lipoprotein profiles were similar between genders. Highly sensitive C-reactive protein (CRP) levels were elevated and similar between genders (p = .4). Leukocyte adhesion molecules (intercellular adhesion molecule 1, vascular adhesion molecule 1, E-selectin) and monocyte chemoattractant protein 1 were elevated, whereas adiponectin levels were below normal in both gender groups. Urinary albumin excretion was similar between genders and did not show any relationship with any of the variables. In women, there was a direct relationship between waist circumference and high-sensitivity CRP levels (rho = .53, p = .01). No other significant relationships were observed. Eighteen Latin American patients with type 2 diabetes completed up to 104 weeks of post-intervention with insulin monotherapy. In these patients, glycemic, lipoprotein, and anthropometric measurements were obtained every 12 weeks. Highly sensitive CRP, leukocyte adhesion molecules, and urinary albumin excretion, among other tests, were obtained every 52 weeks. At 52 and 104 weeks, body weight, BMI, waist circumference, and percent body fat increased in a parallel and significant manner. Despite a significant decrease in percent hemoglobin A1c (22.2%; p = < .0001), lipid and lipoprotein profiles, highly sensitive CRP, leukocyte adhesion molecules, and other nontraditional CV risk factors did not change significantly.

CONCLUSIONS

In young, obese, Latino type 2 diabetic patients, improvement in glycemic control with insulin monotherapy was not associated with a parallel improvement in markers of vascular inflammation. Premenopausal Latino women with uncontrolled type 2 diabetes have CV risks comparable to Latino diabetic men of the same age. Obesity and underlying insulin resistance may counteract the potential CV benefits associated with insulin therapy in lean diabetic patients. Weight loss could be a potential therapeutic modality to improve CV risk in Latino type 2 diabetic patients, especially women.

Cocoa, glucose tolerance, and insulin signaling: cardiometabolic protection

Experimental and clinical evidence reported that some polyphenol-rich natural products may offer opportunities for the prevention and treatment of type 2 diabetes, due to their biological properties. Natural products have been suggested to modulate carbohydrate metabolism by various mechanisms, such as restoring β-cell integrity and physiology and enhancing insulin-releasing activity and glucose uptake. Endothelium is fundamental in regulating arterial function, whereas insulin resistance plays a pivotal role in pathophysiological mechanisms of prediabetic and diabetic states. Glucose and insulin actions in the skeletal muscle are improved by insulin-dependent production of nitric oxide, favoring capillary recruitment, vasodilatation, and increased blood flow. Endothelial dysfunction, with decreased nitric oxide bioavailability, is a critical step in the development of atherosclerosis. Furthermore, insulin resistance has been described, at least in part, to negatively affect endothelial function. Consistent with this, conditions of insulin resistance are usually linked to endothelial dysfunction, and the exposure of the endothelial cells to cardiovascular risk factors such as hypertension, dyslipidemia, and hyperglycemia is associated with reduced nitric oxide bioavailability, resulting in impaired endothelial-dependent vasodilatation. Moreover, endothelial dysfunction has been described as an independent predictor of cardiovascular risk and events. Cocoa and cocoa flavonoids may positively affect the pathophysiological mechanisms involved in insulin resistance and endothelial dysfunction with possible benefits in the prevention of cardiometabolic diseases.

Co-activator binding protein PIMT mediates TNF-α induced insulin resistance in skeletal muscle via the transcriptional down-regulation of MEF2A and GLUT4

The mechanisms underlying inflammation induced insulin resistance are poorly understood. Here, we report that the expression of PIMT, a transcriptional co-activator binding protein, was up-regulated in the soleus muscle of high sucrose diet (HSD) induced insulin resistant rats and TNF-α exposed cultured myoblasts. Moreover, TNF-α induced phosphorylation of PIMT at the ERK1/2 target site Ser²⁹⁸. Wild type (WT) PIMT or phospho-mimic Ser298Asp mutant but not phospho-deficient Ser298Ala PIMT mutant abrogated insulin stimulated glucose uptake by L6 myotubes and neonatal rat skeletal myoblasts. Whereas, PIMT knock down relieved TNF-α inhibited insulin signaling. Mechanistic analysis revealed that PIMT differentially regulated the expression of GLUT4, MEF2A, PGC-1α and HDAC5 in cultured cells and skeletal muscle of Wistar rats. Further characterization showed that PIMT was recruited to GLUT4, MEF2A and HDAC5 promoters and overexpression of PIMT abolished the activity of WT but not MEF2A binding defective mutant GLUT4 promoter. Collectively, we conclude that PIMT mediates TNF-α induced insulin resistance at the skeletal muscle via the transcriptional modulation of GLUT4, MEF2A, PGC-1α and HDAC5 genes.

Insulin resistance is associated with lower acetylcholine-induced microvascular reactivity in nondiabetic women

BACKGROUND

The association between insulin resistance and microvascular dysfunction is well established in obese individuals with type 2 diabetes. It is unclear whether this relationship is dependent on obesity and body fat in insulin-resistant persons. This study investigated acetylcholine (ACh)-induced microvascular reactivity in apparently healthy women (n=37, 20-45 years), with and without insulin resistance.

METHODS

Body fat mass (dual X-ray absorptiometry), waist circumference (WC), blood pressure, fasting glucose, insulin, and free fatty acid concentrations were measured. Insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR), and subjects were divided into insulin-resistant (IR, n=16) and insulin-sensitive (IS, n=21) groups. ACh-induced forearm microvascular reactivity was measured by laser Doppler imagery using iontophoresis of ACh and compared between groups adjusting for WC and skin resistance (SR).

RESULTS

The IR group had a higher body mass index (BMI) (30.7 ± 6.4 vs. 22.9 ± 7.3 kg/m(2), P < 0.01), fat mass (34.7 ± 11.9 vs. 19.7 ± 9.6 kg, P < 0.01), WC (89.9 ± 13.6 vs. 74.4 ± 9.7 cm, P < 0.01), and a lower SR (0.24 ± 0.08 vs. 0.32 ± 0.08 Ω, P < 0.05) than the IS group. Microvascular reactivity, expressed as percentage increase in perfusion from baseline, was significantly lower in IR subjects after adjusting for differences in WC and SR (420.9 ± 166.5 vs. 511.6 ± 214.8%, P < 0.05). There were associations between microvascular reactivity and SR (r=-0.34, P < 0.05) and systolic blood pressure (r=-0.36, P < 0.05), but not BMI, body fat mass, WC, or HOMA-IR.

CONCLUSION

ACh-induced microvascular reactivity was different between IR and IS apparently healthy, nondiabetic women once differences in WC and SR were accounted for.

Precocious markers of cardiovascular risk and vascular damage in apparently healthy women with previous gestational diabetes

Previous gestational diabetes mellitus (pGDM) indicates future risk for type 2 diabetes (T2DM). Insulin resistance (IR) may precede T2DM in many years and is associated with an increased risk for cardiovascular diseases.

AIM

This study aims to identify endothelial dysfunction and cardiovascular risk factors in women with pGDM.

METHODS

This cross-sectional analysis included 45 non diabetic women, 20 pGDM and 25 controls, at least one year after delivery. Body mass index (BMI), abdominal circumference (AC), blood pressure, serum lipids, liver enzymes, uric acid, nonesterified fatty acids, C-reactive protein and plasma glucose, insulin, fibrinogen and plasminogen activator inhibitor 1 were measured. HOMA IR and β were calculated. Pre and post induced ischemia videocapillaroscopy was performed in hand nailfold to evaluate microvascular morphologic aspect and functional response.

RESULTS

AC and fasting glucose were significantly higher in pGDM (p = 0.01 and p = 0.002 respectively). Women with pGDM and BMI < 25 kg/m(2) had significantly higher levels of fasting insulin and HOMA IR than controls (p = 0.008 and 0.05 respectively). Abnormal morphologic findings were more frequent and papillae rectification were 3.3 times more prevalent in pGDM (p = 0.003). Other microvascular parameters did not differ between groups.

CONCLUSION

Cardiovascular risk factors and a microcirculation abnormality (papillae rectification) were significantly increased in young non-diabetic women with pGDM.

Young Hispanics at risk of type 2 diabetes display endothelial activation, subclinical inflammation and alterations of coagulation and fibrinolysis

BACKGROUND

Hispanics have a high rate of diabetes that exposes them to an increased risk of cardiovascular disease. We hypothesized that many of the pathophysiological mechanisms that cause atherosclerotic disease may be present in young Hispanics who do not have clinical diabetes but are at increased risk of developing it.

METHODS

We studied 36 young Hispanic adults without diabetes (ages 18-40). Seventeen participants were at increased risk of developing type 2 diabetes given by overweight and a family history of diabetes on one or both parents (at risk group). Nineteen participants with normal body-mass index and no parental history of diabetes constituted the control group. We measured and compared plasma markers of endothelial dysfunction, disturbed coagulation and fibrinolysis, subclinical inflammation and adipose tissue dysfunction in the at risk and control groups.

RESULTS

Participants at risk of diabetes were more insulin-resistant according to different indicators, and had significantly higher levels of soluble intercellular adhesion molecule-1 (sICAM-1), tissue plasminogen activator (tPA), inhibitor of plasminogen activator-1 (PAi-1), high sensitivity C-reactive protein and free fatty acids, signaling the presence of multiple proatherogenic alterations despite the absence of overt diabetes. Levels of the prothrombotic molecule PAi-1 were most elevated in participants who were not only at risk of diabetes by the study definition, but also abdominally obese.

CONCLUSIONS

Young adult Hispanics at risk of type 2 diabetes but without overt disease already bear considerably high levels of markers reflecting processes that lead to the development of atherosclerotic cardiovascular disease.

Preeclampsia as a risk factor for diabetes: a population-based cohort study

BACKGROUND

Women with preeclampsia (PEC) and gestational hypertension (GH) exhibit insulin resistance during pregnancy, independent of obesity and glucose intolerance. Our aim was to determine whether women with PEC or GH during pregnancy have an increased risk of developing diabetes after pregnancy, and whether the presence of PEC/GH in addition to gestational diabetes (GDM) increases the risk of future (postpartum) diabetes.

METHODS AND FINDINGS

We performed a population-based, retrospective cohort study for 1,010,068 pregnant women who delivered in Ontario, Canada between April 1994 and March 2008. Women were categorized as having PEC alone (n=22,933), GH alone (n=27,605), GDM alone (n=30,852), GDM+PEC (n=1,476), GDM+GH (n=2,100), or none of these conditions (n=925,102). Our main outcome was a new diagnosis of diabetes postpartum in the following years, up until March 2011, based on new records in the Ontario Diabetes Database. The incidence rate of diabetes per 1,000 person-years was 6.47 for women with PEC and 5.26 for GH compared with 2.81 in women with neither of these conditions. In the multivariable analysis, both PEC alone (hazard ratio [HR]=2.08; 95% CI 1.97-2.19) and GH alone (HR=1.95; 95% CI 1.83-2.07) were risk factors for subsequent diabetes. Women with GDM alone were at elevated risk of developing diabetes postpartum (HR=12.77; 95% CI 12.44-13.10); however, the co-presence of PEC or GH in addition to GDM further elevated this risk (HR=15.75; 95% CI 14.52-17.07, and HR=18.49; 95% CI 17.12-19.96, respectively). Data on obesity were not available.

CONCLUSIONS

Women with PEC/GH have a 2-fold increased risk of developing diabetes when followed up to 16.5 years after pregnancy, even in the absence of GDM. The presence of PEC/GH in the setting of GDM also raised the risk of diabetes significantly beyond that seen with GDM alone. A history of PEC/GH during pregnancy should alert clinicians to the need for preventative counseling and more vigilant screening for diabetes. Please see later in the article for the Editors' Summary.

Association of dietary vitamin C and e intake and antioxidant enzymes in type 2 diabetes mellitus patients

BACKGROUND

Diabetes mellitus consist of a various metabolic diseases such as hyperglycemia, increase glycosylated hemoglobin (HbA1c) and disorder in antioxidant enzymes activity, hence supplementing with antioxidant nutrients, mainly vitamin C and E seems to reduce oxidative injure in patients with type 2 diabetes mellitus (T2DM).

AIM

To evaluate outcome of vitamin C and E supplementation on type 2 DM patients.

SETTING AND DESIGN

The study was completed in 170 T2DM on consumption of vitamin C, E, combination of C & E and placebo.

MATERIALS AND METHODS

The cases groups of this study consist of two major groups, which were named supplementation and placebo group. The group of supplementation consisted of 3 sub-groups, which received three capsules per day for a phase of three months. The parameters such as HbA1c, glucose, superoxide dismutase (SOD) and glutathione peroxides (GSH) were evaluated in baseline and after three months with supplementation.

STATISTICAL ANALYSES

The statistical analyses were evaluated with the use of mean ± SD, ANOVA-test and paired-sample t-test.

RESULTS

Mean age of 170 patients, 84 male and 86 female were 53.82±5.26 in the range of 30-60 years. The blood pressure results showed significant differences between the all supplement groups in baseline as compared to after receiving supplements (p<0.05). Use of vitamin C, E, and E & C showed significant differences in concentration of plasma FBS and HbA1c (p<0.05 & <0.001), but there was no significant differences in placebo groups. SOD and GSH enzymes levels showed a significant increased after consumption of vitamins in supplementation groups (p<0.001).

CONCLUSION

This research confirmed that subjects with T2DM after three months supplementation of vitamins demonstrated significantly low level of hypertension, decrease levels of blood glucose, and increase SOD and GSH enzyme activity that can probably reduce insulin resistance by enhanced lowering oxidative stress parameters.

Obesity and metabolic syndrome as related to cardiovascular disease

The metabolic syndrome (MetS) constitutes a multifaceted disorder, including obesity, dyslipidemia, hyperglycemia and hypertension, associated with an increased propensity towards cardiovascular disease (CVD). Besides this, accumulating data suggest the involvement of nontraditional, novel, cardiovascular risk factors in MetS. Among them, insulin resistance seems to possess a predominant role in MetS-related CVD in obese patients. Furthermore, adipose tissue fatty acid metabolism, increased incidence of oxidative stress and endothelial dysfunction, and excessive production of adipocyte derivatives, known as adipokines, have all been proposed to contribute to the pathogenesis of CVD in obese patients with MetS. Lifestyle interventions, such as weight loss and increased physical activity, have long been the cornerstone for the treatment of obesity-related disorders. With the exception of obesity, pharmaceutical interventions targeting each disorder of MetS have yielded considerable improvement in cardiovascular morbidity and mortality. The long-term management of obesity and its complications seems promising but requires further investigation.

TNF-α induces endothelial dysfunction via PKC-ζ-dependent NADPH oxidase activation

Endothelial dysfunction is implicated in a variety of cardiovascular diseases although the detailed mechanisms are not yet completely understood. A relationship has been suggested to exist between inflammation and endothelial dysfunction. TNF-α serves as one of the most important pro-inflammatory cytokines. The main objectives of the present study were to explore the effect of PKC-ζ on TNF-α-impaired endothelial function as well as the underlying mechanisms. Acetylcholine-induced endothelium-dependent vasodilation of mouse thoracic aorta stimulated by TNF-α was initially determined. PKC-ζ deficient mice and the specific inhibitor of NADPH oxidase were respectively applied to elucidate their roles in TNF-α-induced endothelial dysfunction. In vitro superoxide generation in HAECs was detected by DHE staining after administration of TNF-α. Meanwhile, the regulatory p47(phox) subunit of NADPH oxidase was evaluated by Western blotting and RT-PCR. The results showed that TNF-α conspicuously impaired endothelium-dependent vasodilation and the impairment was attenuated by either depleting PKC-ζ or inhibiting NADPH oxidase. In vitro TNF-α increased superoxide production and p47(phox) expression in HAECs, and such increases could be ameliorated by the specific PKC-ζ inhibitor. Our findings suggest that superoxide over-production triggered by PKC-ζ-dependent NADPH oxidase activation contributes to TNF-α-induced endothelial dysfunction.

Perivascular Fat and the Microcirculation: Relevance to Insulin Resistance, Diabetes, and Cardiovascular Disease

Type 2 diabetes and its major risk factor, obesity, are a growing burden for public health. The mechanisms that connect obesity and its related disorders, such as insulin resistance, type 2 diabetes, and hypertension, are still undefined. Microvascular dysfunction may be a pathophysiologic link between insulin resistance and hypertension in obesity. Many studies have shown that adipose tissue-derived substances (adipokines) interact with (micro)vascular function and influence insulin sensitivity. In the past, research focused on adipokines from perivascular adipose tissue (PVAT). In this review, we focus on the interactions between adipokines, predominantly from PVAT, and microvascular function in relation to the development of insulin resistance, diabetes, and cardiovascular disease.

Serum C-reactive protein level and prediabetes in two Asian populations

AIMS/HYPOTHESIS

Prediabetes, an early stage in the hyperglycaemic continuum, increases the future risk of developing diabetes and cardiovascular disease (CVD). C-reactive protein (CRP), a marker of inflammation, is associated with diabetes and CVD. However, studies examining the association between CRP and prediabetes among participants without diabetes are limited.

METHODS

We analysed data from two large population-based studies in Singapore: the Singapore Prospective Study Programme (SP2, n = 4,252 Chinese, Malay and Indians aged ≥ 24 years) and the Singapore Malay Eye Study (SiMES, n = 2,337 Malays aged 40-80 years), participants of which were free of diabetes mellitus. Prediabetes was defined as glycated haemoglobin of 5.7-6.4% in SiMES (n = 1,231); fasting plasma glucose of 5.6-6.9 mmol/l in SP2 (n = 386).

RESULTS

Elevated high sensitivity CRP (hsCRP) levels were found to be associated with prediabetes after adjusting for age, sex, race-ethnicity, education, smoking, alcohol consumption, hypertension, BMI and total cholesterol. Comparing those with hsCRP <1 mg/l (referent), the OR (95% confidence interval) of prediabetes in persons with hsCRP 1-3 mg/l and >3 mg/l was 1.31 (0.99-1.74) and 2.17 (1.61-2.92), p (trend) < 0.0001 in SP2; 1.23 (1.00-1.52) and 1.31 (1.06-1.64), p (trend) = 0.02 in SiMES. In subgroup analysis, the association was stronger in women, Chinese and Malays, and participants with BMI < 25 kg/m(2).

CONCLUSIONS

Data from two population-based Asian cohorts suggest that elevated serum hsCRP levels are associated with prediabetes.

Dehydroepiandrosterone to induce murine models for the study of polycystic ovary syndrome

During the last decade a battery of animal models used for the study of polycystic ovary syndrome (PCOS) have allowed a focus on different aspects of the pathology. Since dehydroepiandrosterone (DHEA) was found to be one of the most abundant circulating androgens in women with PCOS, a rodent model showing the salient features found in women with PCOS was developed by the injection of DHEA. Although insulin-sensitizing agents, such as biguanides, are clinically used in the treatment of diabetes and PCOS, the complete understanding of their mechanisms of action remains unknown. The present review discusses the molecular mechanisms involved in the development of PCOS by using the DHEA-PCOS murine model and analyzes the role of the biguanide metformin as treatment.

Fenofibrate reduces systemic inflammation markers independent of its effects on lipid and glucose metabolism in patients with the metabolic syndrome

CONTEXT

Fenofibrate is a peroxisome proliferator-activated receptor alpha agonist widely used in clinical practice, but its mechanism of action is incompletely understood.

OBJECTIVE

The aim of the study was to assess whether improvement in subclinical inflammation or glucose metabolism contributes to its antiatherogenic effects in insulin-resistant subjects with the metabolic syndrome (MetS).

DESIGN AND SETTING

We conducted a randomized, double-blind, placebo-controlled study in the research unit at an academic center.

PATIENTS

We studied 25 nondiabetic insulin-resistant MetS subjects.

INTERVENTION(S)

We administered fenofibrate (200 mg/d) and placebo for 12 wk.

MAIN OUTCOME MEASURES

Before and after treatment, we measured plasma lipids/apolipoproteins, inflammatory markers (high-sensitivity C-reactive protein, IL-6, intercellular adhesion molecule/vascular cell adhesion molecule), adipocytokines (adiponectin, TNFalpha, leptin), and insulin secretion (oral glucose tolerance test). We also assessed adipose tissue, hepatic and peripheral (muscle) insulin resistance fasting and during a euglycemic insulin clamp with (3)H glucose and (14)C palmitate infusion combined with indirect calorimetry.

RESULTS

Subjects displayed severe insulin resistance and systemic inflammation. Fenofibrate significantly reduced plasma triglyceride, apolipoprotein (apo) CII, apo CIII, and apo E (all P < 0.01), with a modest increase in high-density lipoprotein-cholesterol (+12%; P = 0.06). Fenofibrate markedly decreased plasma high-sensitivity C-reactive protein by 49.5 +/- 8% (P = 0.005) and IL-6 by 29.8 +/- 7% (P = 0.03) vs. placebo. However, neither insulin secretion nor adipose tissue, hepatic or muscle insulin sensitivity or glucose/lipid oxidation improved with treatment. Adiponectin and TNF-alpha levels were also unchanged. Improvement in plasma markers of vascular/systemic inflammation was dissociated from changes in triglyceride/high-density lipoprotein-cholesterol, apo CII/CIII, or free fatty acid concentrations or insulin secretion/insulin sensitivity.

CONCLUSIONS

In subjects with the MetS, fenofibrate reduces systemic inflammation independent of improvements in lipoprotein metabolism and without changing insulin sensitivity. This suggests a direct peroxisome proliferator-activated receptor alpha-mediated effect of fenofibrate on inflammatory pathways, which may be important for the prevention of CVD in high-risk patients.

Long-term benefits of insulin therapy and glycemic control in overweight and obese adults with type 2 diabetes

PROBLEM

Obesity and type 2 diabetes have reached epidemic proportions in the United States. Obese patients are at especially high risk for the development of metabolic syndrome, a clustering of metabolic abnormalities associated with insulin resistance that usually precede the development of cardiovascular disease. Overweight or obesity, along with insulin resistance, is frequently present in people with type 2 diabetes.

METHODS

A literature search of the PubMed and MEDLINE databases, using the terms diabetes, obesity, metabolic syndrome, glycemic control, antidiabetic therapy, and insulin, was performed. Articles published between 1985 and 2006 that examined diabetes management in the obese population were selected and reviewed.

RESULTS

There is new evidence suggesting that tight glycemic control and earlier initiation of insulin therapy can improve outcomes in obese patients with type 2 diabetes, thereby reducing the risk for the development of both macrovascular and microvascular complications of the disease. Insulin also appears to exhibit anti-inflammatory effects, which may provide additional protection against the development of atherosclerosis. Despite the benefits of insulin therapy, many patients and physicians remain reluctant to start insulin due to concerns about weight gain.

CONCLUSION

Newer insulin formulations can effectively improve glycemic control without significant effects on patient weight and, therefore, may be particularly useful in patients who are overweight or obese. Implementation of comprehensive treatment regimens that emphasize dietary modification, physical activity, and exercise, and aggressive use of pharmacological agents to achieve tight glycemic control through physiological regimens offer the most promise for reducing long-term complications in obese patients with type 2 diabetes.

Efficacy of the dipeptidyl peptidase IV inhibitor isoleucine thiazolidide (P32/98) in fatty Zucker rats with incipient and manifest impaired glucose tolerance

AIM

Incretin enhancers are a new class of antidiabetic drugs with promising therapeutic potential for type 2 diabetes. Therapeutic intervention in prediabetes is an attractive strategy for preventing or delaying diabetes onset. The aim of the present study was to investigate the therapeutic effects of incretin enhancement on incipient impaired glucose tolerance (iIGT) and manifest IGT (mIGT) using the dipeptidyl peptidase IV (DPP-4) inhibitor P32/98- and fatty Zucker rat (ZR, fa/fa) as a model.

METHODS

ZRs were classified into groups with iIGT and mIGT (n = 10 per group). P32/98 (21.61 mg/kg body weight) was administered orally to ZR with iIGT and mIGT once daily for 6 and 3 weeks respectively. Assessments included body weight, morning blood glucose and insulin, oral glucose tolerance test (oGTT; 2 g glucose/kg), plasma parameters and blood glucose day-night profile (DNP). In addition, glucose responsiveness of isolated islets and islet morphology were analysed.

RESULTS

P32/98 decreased non-fasting morning blood glucose more effectively in ZR with iIGT than in ZR with mIGT. Compared with study entry, P32/98 improved DNP of blood glucose in ZR with mIGT and nearly normalized DNP in ZR with iIGT. An acute bolus of inhibitor reduced glucose load during oGTT in rats chronically treated with placebo or P32/98. In contrast to placebo-treated rats, rats receiving long-term treatment with P32/98 required less insulin during oGTT. This effect was larger in rats with iIGT vs. rats with mIGT. In isolated pancreatic islets of ZR with mIGT, treatment with P32/98 decreased pancreatic insulin content and increased glucose responsiveness, while the beta-cell volume density was unaffected. P32/98 significantly reduced triglycerides and non-esterified fatty acids. Intestinal growth was comparable between inhibitor- and placebo-treated fatty rats.

CONCLUSIONS

Enhancement of incretin with the DPP-4 inhibitor P32/98 has therapeutic effects in hyperinsulinaemia, hyperglycaemia and IGT in ZR with iIGT and mIGT. Apparently, administration of P32/98 in ZR with iIGT results in more efficient beta-cell function, which is associated with less need for insulin to cope with deterioration of glucose tolerance. Importantly, P32/98 has a strong effect on dyslipidaemia in mIGT. P32/98 has no side effect on intestinal growth. Daily intake of P32/98 is a promising strategy for treatment of glucose intolerance and has the potential to prevent type 2 diabetes.

Metabolic syndrome in Italian patients with bipolar disorder

OBJECTIVE

This study aimed to evaluate the prevalence of metabolic syndrome (MetS) in Italian patients with bipolar disorder (BD) and to determine the sociodemographic and clinical correlates of MetS in this patient population.

METHOD

Subjects with BD I and II were included. Sociodemographic and clinical characteristics, lifestyle information (alcohol and smoking habits and rate of physical exercise) and comorbidity for cardiovascular diseases and diabetes were collected. Patients were assessed for MetS according to both National Cholesterol Education Program Adult Treatment Panel III and International Diabetes Federation (IDF) criteria.

RESULTS

MetS was evaluated in 99 patients out of 108 who were enrolled. MetS was present in 25.3% of the sample. Abdominal obesity was present in 50%, hypertension in 40%, high triglycerides in 34.7%, low HDL-C levels in 32.3% and fasting hyperglycemia in 11% of the sample. Prevalence of MetS was 30% when IDF criteria were employed. Of the investigated variables, age, duration of illness, rate of obesity and cardiovascular disease were higher in patients with MetS. After the regression analysis, only age and obesity were associated to MetS.

CONCLUSIONS

MetS is highly prevalent in Italian patients with BD. Our 25.3% prevalence rate is consistent with the 21-22% reported in other European studies and lower than that in U.S. studies. Elderly and obese patients with BD are at particularly high risk for MetS.

Overweight Latino children and adolescents have marked endothelial dysfunction and subclinical vascular inflammation in association with excess body fat and insulin resistance

OBJECTIVE

We measured plasma markers of endothelial dysfunction, vascular inflammation, and pro-coagulation in obese Hispanic/Latino children and adolescents with normal glucose tolerance and determined their relationship to body composition and indexes of glucose and lipid metabolism.

RESEARCH DESIGN AND METHODS

A total of 38 lean or obese Hispanic children and adolescents (10-18 years of age) were selected. The overweight group (n = 21) had a BMI >85th percentile for their age and sex, and the lean group (n = 17) had a BMI between the 25th and 50th percentiles. Studies included an oral glucose tolerance test, measurements of plasma glucose and lipids, several markers of endothelial function and inflammation, and determination of body composition by dual X-ray absorptiometry.

RESULTS

The obese group had higher systolic blood pressure and plasma triglycerides and was more insulin resistant than the lean group. The obese group also had higher plasma soluble intercellular adhesion molecule (259.5 +/- 60.0 vs. 223.2 +/- 47.5 ng/ml, P = 0.047), tumor necrosis factor-alpha (2.57 +/- 1.1 vs. 1.74 +/- 0.6 pg/ml, P = 0.008), high-sensitivity C-reactive protein (2.0 vs. 0.13 mg/l, P < 0.0001), plasminogen-activated inhibitor-1 (47.0 +/- 35.7 vs. 12.0 +/- 5.2 ng/ml, P < 0.0001), tissue plasminogen activator (6.1 +/- 1.9 vs. 4.1 +/- 0.8 ng/ml, P = 0.001), and white blood cell count (6.9 vs. 5.3 x 10(3), P = 0.031) and lower levels of adiponectin (8.7 +/- 3.3 vs. 12.6 +/- 5.2 microg/ml, P = 0.022). No significant differences were observed for soluble vascular cell adhesion molecule or interleukin-6.

CONCLUSIONS

Overweight Hispanic children and adolescents with normal glucose tolerance exhibit increased plasma markers of endothelial dysfunction and subclinical inflammation in association with obesity and insulin resistance. These abnormalities may predispose them to the development of type 2 diabetes and cardiovascular disease.

The relationship between alcohol consumption and glycemic control among patients with diabetes: the Kaiser Permanente Northern California Diabetes Registry

BACKGROUND

Alcohol consumption is a common behavior. Little is known about the relationship between alcohol consumption and glycemic control among people with diabetes.

OBJECTIVE

To evaluate the association between alcohol consumption and glycemic control.

DESIGN

Survey follow-up study, 1994-1997, among Kaiser Permanente Northern California members.

PATIENTS

38,564 adult diabetes patients.

MEASUREMENTS

Self-reported alcohol consumption, and hemoglobin A1C (A1C), assessed within 1 year of survey date. Linear regression of A1C by alcohol consumption was performed, adjusted for sociodemographic variables, clinical variables, and diabetes disease severity. Least squares means estimates were derived.

RESULTS

In multivariate-adjusted models, A1C values were 8.88 (lifetime abstainers), 8.79 (former drinkers), 8.90 (<0.1 drink/day), 8.71 (0.1-0.9 drink/day), 8.51 (1-1.9 drinks/day), 8.39 (2-2.9 drinks/day), and 8.47 (>/=3 drinks/day). Alcohol consumption was linearly (p < 0.001) and inversely (p = 0.001) associated with A1C among diabetes patients.

CONCLUSIONS

Alcohol consumption is inversely associated with glycemic control among diabetes patients. This supports current clinical guidelines for moderate levels of alcohol consumption among diabetes patients. As glycemic control affects incidence of complications of diabetes, the lower A1C levels associated with moderate alcohol consumption may translate into lower risk for complications.

Improvement in endothelium dysfunction in diabetics treated with statins: a randomized comparison of atorvastatin 20 mg versus rosuvastatin 10 mg

AIM

To investigate the effect a 3-month treatment with atorvastatin 20 mg compared with rosuvastatin 10 mg on endothelium dysfunction in subjects with diabetes.

METHODS

A total of 22 consecutive subjects with diabetes who were not receiving statins were enrolled in the study. Endothelium function was assessed before treatment (T0), after 1 month (T1), and after 3 months of treatment (T2) with statins with brachial echo-Doppler test. Patients were randomized to receive atorvastatin 20 mg or rosuvastatin 10 mg. Blood samples were drawn in the meantime in order to evaluate C-reactive protein (CRP) plasmatic concentrations.

RESULTS

A total of 82% of patients enrolled showed endothelium dysfunction (hyperemic reserve <5%). Treatment with statins significantly improved endothelium function in diabetics. Subjects with endothelium dysfunction decreased from 82% (T0) to 44% (T2): mean hyperemic reserve values increased from 2.64% (T0) to 3.23% (T1) and 4% (T2) in patients treated with rosuvastatin (ANOVA P < 0.01), and from 2.74% (T0) to 2.75% (T1) and 4.40% (T2) in those treated with atorvastatin (ANOVA P < 0.01); differences were significant only comparing T2 with T0. Relative increase in endothelium reserve was 51.51% with rosuvastatin versus 60.58% with atorvastatin (P N.S.). Both statins significantly reduced plasmatic levels of CRP (3.18 +/- 2.43 mg/dL [T0] vs. 1.31 +/- 1.67 mg/dL [T2] with rosuvastatin [P < 0.01], 7.53 +/- 7.46 mg/dL [T0] vs. 2.92 +/- 2.06 mg/dL [T2] with atorvastatin [P < 0.01]). Relative reduction of CRP levels was -50.57% with rosuvastatin versus -36.28% with atorvastatin (P N.S.).

CONCLUSION

A 3-month treatment with either atorvastatin 20 mg or rosuvastatin 10 mg is effective in improving endothelium dysfunction in subjects with diabetes.

Development of multiple complications in type 2 diabetes is associated with the increase of multiple markers of chronic inflammation

Patients with type 2 diabetes (T2DM) are known at risk for developing cardiovascular disease (CVD), nephropathy, and cancer. We were interested to find out whether multiple markers associated with chronic inflammation are detectable in patients with T2DM and are increased in patients with T2DM who developed additional clinical complications. A sequence of multiple risk markers for atherogenesis, associated with chronic inflammation, was measured in patients with T2DM before and after the development of clinical complications. We found that multiple clinical complications frequently developed simultaneously in patients with T2DM. At the early stage of T2DM, only low levels and low percent elevations of multiple risk markers were detected. However, both the level and the percent elevation of these markers were found to increase with disease progression and the development of clinical complications. We believe that chronic inflammation not only contributes to the pathogenesis of T2DM but also continues to increase in T2DM patients who are developing additional clinical complications. It appears that these multiple markers are potentially useful not only for monitoring the progression of T2DM but also predicting the risk of developing macro- and microvascular disease, nephropathy, and cancer.

Microvascular dysfunction in obesity: a potential mechanism in the pathogenesis of obesity-associated insulin resistance and hypertension

Obesity is an important risk factor for insulin resistance and hypertension and plays a central role in the metabolic syndrome. Insight into the pathophysiology of this syndrome may lead to new treatments. This paper has reviewed the evidence for an important role for the microcirculation as a possible link between obesity, insulin resistance and hypertension.

Determinants of incident hyperglycemia 6 years after delivery in young rural Indian mothers: the Pune Maternal Nutrition Study (PMNS)

OBJECTIVE

To study determinants of incident hyperglycemia in rural Indian mothers 6 years after delivery.

RESEARCH DESIGN AND METHODS

The Pune Maternal Nutrition Study collected information in six villages near Pune on prepregnant characteristics and nutrition, physical activity, and glucose tolerance during pregnancy. An oral glucose tolerance test (OGTT) was repeated 6 years after delivery.

RESULTS

A total of 597 mothers had an OGTT at 28 weeks' gestation; 3 had gestational diabetes (by World Health Organization 1999 criteria). Six years later, 42 of 509 originally normal glucose-tolerant mothers were hyperglycemic (8 diabetic, 20 with impaired glucose tolerance, and 14 with impaired fasting glucose). The hyperglycemic women had shorter legs and thicker skinfolds before pregnancy (P < 0.01, both), were less active and more hyperglycemic (2-h plasma glucose 4.8 vs. 4.4 mmol/l, P < 0.001) during pregnancy, and gained more weight during follow-up (6.0 vs. 2.7 kg, P < 0.001). Multivariate analysis revealed that total leukocyte count and blood pressure during pregnancy were additional independent predictors of 2-h glucose concentration at follow-up.

CONCLUSIONS

Our results suggest that compromised linear growth, adiposity, inflammation, and less physical activity predispose to hyperglycemia in young rural Indian women. International cut points of diabetes risk factors are largely irrelevant in these women.

CB1 receptors: emerging evidence for central and peripheral mechanisms that regulate energy balance, metabolism, and cardiovascular health

Insulin resistance, dyslipidaemia and obesity are the major cardiometabolic risk factors contributing to the development of type 2 diabetes and cardiovascular disease (CVD). Owing to the increasing prevalence of obesity, type 2 diabetes, and CVD, new and effective pharmacologic therapies are urgently needed. In this regard, the endogenous cannabinoid system (ECS), a neuromodulatory system involved in the regulation of various aspects of energy balance and eating behaviour through central and peripheral mechanisms, may present the potential to meet this need. In the central nervous system (CNS), cannabinoid type 1 (CB1) receptors and their respective ligands, the endocannabinoids, have a significant role in the modulation of food intake and motivation to consume palatable food. CB1 receptors have also been found in organs involved in the regulation of metabolic homeostasis, such as liver, white adipose tissue, muscle and pancreas. Dysregulation of the ECS has been associated with the development of dyslipidaemia, glucose intolerance, and obesity, and CB1 receptor blockade may have a role in ameliorating these metabolic abnormalities. Thus, pharmacologic options targeting the ECS may provide a novel, effective approach to the prevention and management of CVD, type 2 diabetes and obesity.