Improved skeletal muscle oxidative enzyme activity and restoration of PGC-1α and PPARß/δ gene expression upon rosiglitazone treatment in obese patients with type 2 diabetes mellitus

Objective: To examine whether rosiglitazone alters gene expression of some key genes involved in mitochondrial biogenesis and oxidative capacity in skeletal muscle of type 2 diabetic patients, and whether this is associated with alterations in skeletal muscle oxidative capacity and lipid content.

Design: Skeletal muscle gene expression, mitochondrial protein content, oxidative capacity and lipid accumulation were measured in muscle biopsies obtained from diabetic patients, before and after 8 weeks of rosiglitazone treatment, and matched controls. Furthermore, whole-body insulin sensitivity and substrate utilization were assessed.

Subjects: Ten obese type 2 diabetic patients and 10 obese normoglycemic controls matched for age and BMI.

Methods: Gene expression and mitochondrial protein content of complexes I–V of the respiratory chain were measured by quantitative polymerase chain reaction and Western blotting, respectively. Histochemical staining was used to quantify lipid accumulation and complex II succinate dehydrogenase (SDH) activity. Insulin sensitivity and substrate utilization were measured during a hyperinsulinemic–euglycemic clamp with indirect calorimetry.

Results: Skeletal-muscle mRNA of PGC-1a and PPARb/d – but not of other genes involved in glucose, fat and oxidative metabolism – was significantly lower in diabetic patients (Po0.01). Rosiglitazone significantly increased PGC-1a (B2.2-fold, Po0.01) and PPARb/d (B2.6-fold, Po0.01), in parallel with an increase in insulin sensitivity, SDH activity and metabolic flexibility (Po0.01). Surprisingly, none of the measured mitochondrial proteins was reduced in type 2 diabetic patients, nor affected by rosiglitazone treatment. No alterations were seen in muscular fat accumulation upon treatment.

Conclusion: These results suggest that the insulin-sensitizing effect of rosiglitazone may involve an effect on muscular oxidative capacity, via PGC-1a and PPARb/d, independent of mitochondrial protein content and/or changes in intramyocellular lipid.

Aerobic exercise and resistance training for the management of type 2 diabetes mellitus

BACKGROUND
Implementation of a structured physical exercise program can improve glycemic control in patients with type 2 diabetes mellitus.

OBJECTIVE
To evaluate the efficacy of aerobic exercise and resistance training (either alone or in combination) in the management of type 2 diabetes mellitus.

DESIGN AND INTERVENTION
DARE (Diabetes Aerobic and Resistance Exercise) was a 26-week, single-center, parallel-group, randomized, controlled trial of patients with type 2 diabetes mellitus of >6 months' duration. Participants were aged 39-70 years with a baseline [HbA.sub.1c] level 6.6-9.9%. Exclusion criteria included current insulin therapy, regular exercise regime and blood pressure >160/95 mmHg. All participants underwent a 4-week run-in period that comprised 12 sessions of combined aerobic exercise and resistance training; participants who attended [greater than or equal to] 10 sessions were eligible to enter the study. Eligible participants were randomly allocated to one of four groups: aerobic exercise alone; resistance training alone; combined aerobic exercise and resistance training; and no intervention (control group). Exercise was performed three times weekly. The aerobic exercise group progressed from 15-20 min on a treadmill or bicycle ergometer per session at 60% of the maximum heart rate to 45 min per session at 75% of the maximum heart rate. The resistance training group performed 7 different exercises on weight machines per 45 min session, and progressed to 2-3 sets of each exercise at the maximum weight that could be lifted 7-9 times. The combined exercise group performed the full aerobic exercise program plus the full resistance training program. Participants in the control group reverted to their pre-study exercise levels.

OUTCOME MEASURES
The primary outcome measure was the change in [HbA.sub.1c] from baseline. Secondary outcome measures included changes in blood pressure, lipid profile, and body composition.

RESULTS
A total of 251 participants were eligible for intervention. The median session attendance was 80% (aerobic exercise), 85% (resistance training) and 86% (combined exercise). When compared with the control group, the HbA1c levels were reduced by 0.50% in the aerobic exercise group (P = 0.007) and by 0.38% in the resistance training group (P = 0.038). The combined exercise group had an additional reduction of 0.46% when compared with the aerobic exercise group (P = 0.014) and of 0.59% when compared with the resistance training group (P = 0.001). Decreases in [HbA.sub.1c] levels were greatest for participants with a baseline [HbA.sub.1c] level = 7.5% (P <0.001). For participants with a baseline level [HbA.sub.1c] <7.5%, significant improvements in glycemic control were observed in the combined exercise group only (P = 0.002). Changes in blood pressure and lipid profiles did not differ between the groups. By contrast, participation in a structured exercise program improved body composition.

CONCLUSION
Although aerobic exercise or resistance training alone improved glycemic control, additional improvements were observed with the combined exercise regimen.

Patient-reported outcomes in trials of incretin-based therapies in patients with type 2 diabetes mellitus

Incretin-based therapies have a glucose-dependent mode of action that results in excellent glucose-lowering efficacy with very low risk of hypoglycaemia, and weight neutrality [dipeptidyl peptidase-4 (DPP-4) inhibitors] or weight loss [glucagon-like peptide-1 (GLP-1) receptor agonists], in people with type 2 diabetes mellitus (T2DM). Patient-reported outcomes (PROs) complement physician evaluations of efficacy and tolerability and offer insights into the subjective experience of using modern diabetes treatments. We conducted a systematic search of clinical trials of the GLP-1 receptor agonists liraglutide, exenatide and long-acting exenatide, one of which included the oral DPP-4 inhibitor sitagliptin as a comparator. No other PRO data for DPP-4 inhibitors were identified. This review summarizes PRO data from eight clinical trials, the majority of which used the Diabetes Treatment Satisfaction Questionnaire (DTSQ) and/or Impact of Weight on Quality of Life-Lite (IWQOL-Lite) to evaluate patient experience. People with T2DM were highly satisfied with modern incretin-based therapies compared with traditional therapies. Treatment satisfaction (including perceptions of convenience and flexibility) was high and generally higher with GLP-1 agonists in association with their greater glucose-lowering efficacy and tendency to facilitate weight loss. Weight-related quality of life (QoL) also improved in people using incretin therapies. The glycaemic improvements achieved with GLP-1 receptor agonists, coupled with the low incidence of hypoglycaemia and ability to cause weight loss, seemed to offset potential concern about injections. It is plausible that superior patient-reported benefits found in clinical trials may translate into improved, clinically meaningful, long-term outcomes through increased treatment acceptability. Long-term, prospective data are needed to ascertain whether this is the case in practice.

Shining the light on sunshine: a systematic review of the influence of sun exposure on type 2 diabetes mellitus-related outcomes

Prospective observational studies uniformly link vitamin D deficiency with the incidence of type 2 diabetes mellitus (T2DM), yet trials supplementing participants at risk of T2DM with vitamin D to reduce progression to T2DM have yielded inconsistent results. Inconsistencies between supplementation trials may be due to insufficient dosing or small sample sizes. Observational studies may also have reported spurious associations due to uncontrolled confounding by lifestyle or genetic factors. Alternatively, observational and intervention studies may not be entirely comparable. Observational studies show an association between higher vitamin D status, which is predominantly derived from sun exposure, and decreased incidence of T2DM. Trials intervene with vitamin D supplementation, and therefore may be missing alternate causes of the effect of sun exposure, as seen in observational studies. We propose that sun exposure may be the driving force behind the associations seen in observational studies; sun exposure may have additional benefits beyond increasing serum 25-hydroxyvitamin D (25OHD) levels. We performed an electronic literature search to identify articles that examined associations between sun exposure and T2DM and/or glucose metabolism. A best evidence synthesis was then conducted using outcomes from analyses deemed to have high methodological quality. Ten eligible full-text articles were identified, yielding 19 T2DM-related outcomes. The best evidence analysis considered 11 outcomes which were grouped into six outcome types: T2DM, fasting glucose, glucose tolerance, fasting insulin, insulin secretion and insulin sensitivity. There was moderate evidence to support a role of recreational sun exposure in reducing odds of T2DM incidence. High-level evidence was lacking; evidence presented for other outcomes was of low or insufficient level. This review highlights significant gaps in research pertaining to sun exposure and T2DM-related outcomes. Further research is encouraged as we aim to identify novel preventative strategies for T2DM.

Barriers and enablers to healthcare access and use among Arabic-speaking and Caucasian English-speaking patients with type 2 diabetes mellitus: a qualitative comparative study

OBJECTIVE: The objective of this study was to explore the decision-making processes and associated barriers and enablers that determine access and use of healthcare services in Arabic-speaking and English-speaking Caucasian patients with diabetes in Australia. STUDY SETTING AND DESIGN: Face-to-face semistructured individual interviews and group interviews were conducted at various healthcare settings-diabetes outpatient clinics in 2 tertiary referral hospitals, 6 primary care practices and 10 community centres in Melbourne, Australia. PARTICIPANTS: A total of 100 participants with type 2 diabetes mellitus were recruited into 2 groups: 60 Arabic-speaking and 40 English-speaking Caucasian. DATA COLLECTION: Interviews were audio-taped, translated into English when necessary, transcribed and coded thematically. Sociodemographic and clinical information was gathered using a self-completed questionnaire and medical records. PRINCIPAL FINDINGS: Only Arabic-speaking migrants intentionally delayed access to healthcare services when obvious signs of diabetes were experienced, missing opportunities to detect diabetes at an early stage. Four major barriers and enablers to healthcare access and use were identified: influence of significant other(s), unique sociocultural and religious beliefs, experiences with healthcare providers and lack of knowledge about healthcare services. Compared with Arabic-speaking migrants, English-speaking participants had no reluctance to access and use medical services when signs of ill-health appeared; their treatment-seeking behaviours were straightforward. CONCLUSIONS: Arabic-speaking migrants appear to intentionally delay access to medical services even when symptomatic. Four barriers to health services access have been identified. Tailored interventions must be developed for Arabic-speaking migrants to improve access to available health services, facilitate timely diagnosis of diabetes and ultimately to improve glycaemic control.

Clinical pharmacology of dipeptidyl peptidase 4 inhibitors indicated for the treatment of type 2 diabetes mellitus

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral antidiabetic drugs that improve glycaemic control without causing weight gain or increasing hypoglycaemic risk in patients with type 2 diabetes mellitus (T2DM). The eight available DPP-4 inhibitors, including alogliptin, anagliptin, gemigliptin, linagliptin, saxagliptin, sitagliptin, teneligliptin, and vildagliptin, are small molecules used orally with identical mechanism of action and similar safety profiles in patients with T2DM. DPP-4 inhibitors may be used as monotherapy or in double or triple combination with other oral glucose-lowering agents such as metformin, thiazolidinediones, or sulfonylureas. Although DPP-4 inhibitors have the same mode of action, they differ by some important pharmacokinetic and pharmacodynamic properties that may be clinically relevant in some patients. The main differences between the eight gliptins include: potency, target selectivity, oral bioavailability, elimination half-life, binding to plasma proteins, metabolic pathways, formation of active metabolite(s), main excretion routes, dosage adjustment for renal and liver insufficiency, and potential drug-drug interactions. The off-target inhibition of selective DPP-4 inhibitors is responsible for multiorgan toxicities such as immune dysfunction, impaired healing, and skin reactions. As a drug class, the DPP-4 inhibitors have become accepted in clinical practice due to their excellent tolerability profile, with a low risk of hypoglycaemia, a neutral effect on body weight, and once-daily dosing. It is unknown if DPP-4 inhibitors can prevent disease progression. More clinical studies are needed to validate the optimal regimens of DPP-4 inhibitors for the management of T2DM when their potential toxicities are closely monitored.

An update on the clinical pharmacology of the dipeptidyl peptidase 4 inhibitor alogliptin used for the treatment of type 2 diabetes mellitus.

Alogliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor that is a class of relatively new oral hypoglycaemic drugs used in patients with type 2 diabetes (T2DM), can be used as monotherapy or in combination with other anti-diabetic agents, including metformin, pioglitazone, sulfonylureas and insulin with a considerable therapeutic effect. Alogliptin exhibits favorable pharmacokinetic and pharmacodynamic profiles in humans. Alogliptin is mainly metabolized by cytochrome P450 (CYP2D6) and CYP3A4. Dose reduction is recommended for patients with moderate or worse renal impairment. Side effects of alogliptin include nasopharyngitis, upper-respiratory tract infections and headache. Hypoglycaemia is seen in about 1.5% of the T2DM patients. Rare but severe adverse reactions such as acute pancreatitis, serious hypersensitivity including anaphylaxis, angioedema and severe cutaneous reactions such as Stevens-Johnson syndrome have been reported from post-marketing monitoring. Pharmacokinetic interactions have not been observed between alogliptin and other drugs including glyburide, metformin, pioglitazone, insulin and warfarin. The present review aimed to update the clinical information on pharmacodynamics, pharmacokinetics, adverse effects and drug interactions, and to discuss the future directions of alogliptin.

Prevention of type 2 diabetes in a primary health care setting interim results from the Greater Green Triangle (GGT) Diabetes Prevention Project

Although clinical trials have shown that lifestyle modifications reduce the risk of type 2 diabetes, translating lessons from trials to primary care remains a challenge. The aim of the study was to evaluate efficacy and feasibility of primary care-based diabetes prevention model with modest resource requirements in rural Australia. Three hundred and eleven subjects with at least a moderate risk of type 2 diabetes participated in a combined dietary and physical activity intervention. Clinical measurements and fasting blood samples were taken at the baseline and after intervention. After 3 months intervention, total (change −3.5%, p < 0.001) and LDL cholesterol (−4.8%, p < 0.001) plasma levels as well as body mass index (−2.5%, p < 0.001), weight (−2.5%, p < 0.001), and waist (−1.6%, p < 0.001) and hip (−2.7%, p < 0.001) circumferences reduced significantly. A borderline reduction was found in triglyceride levels (−4.8%, p = 0.058) while no changes were observed in HDL cholesterol (+0.6%, p = 0.525), glucose (+0.06%, p = 0.386), or systolic (−0.98%, p = 0.095) or diastolic (−1.06%, p = 0.134) blood pressure levels. In conclusion, a lifestyle intervention improved health outcomes – especially obesity and blood lipids – in a population at high risk of developing type 2 diabetes. Our results suggest that the present model is effective and feasible to carry out in primary care settings.

Does self monitoring of blood blucose as opposed to urinalysis provide additional benefit in patients newly diagnosed with type 2 diabetes receiving structured education? The DESMOND SMBG randomised controlled trial protocol

Background
The benefit of self-monitoring of blood glucose (SMBG) in people with type 2 diabetes on diet or oral agents other than sulphonylureas remains uncertain. Trials of interventions incorporating education about self-monitoring of blood glucose have reported mixed results. A recent systematic review concluded that SMBG was not cost-effective. However, what was unclear was whether a cheaper method of self-monitoring (such as urine glucose monitoring) could produce comparable benefit and patient acceptability for less cost.

Methods/Design
The DESMOND SMBG trial is comparing two monitoring strategies (blood glucose monitoring and urine testing) over 18 months when incorporated into a comprehensive self-management structured education programme. It is a multi-site cluster randomised controlled trial, conducted across 8 sites (7 primary care trusts) in England, UK involving individuals with newly diagnosed Type 2 diabetes.

The trial has 80% power to demonstrate equivalence in mean HbA1c (the primary end-point) at 18 months of within ± 0.5% assuming 20% drop out and 20% non-consent. Secondary end-points include blood pressure, lipids, body weight and psychosocial measures as well as a qualitative sub-study.

Practices were randomised to one of two arms: participants attend a DESMOND programme incorporating a module on self-monitoring of either urine or blood glucose. The programme is delivered by accredited educators who received specific training about equipoise. Biomedical data are collected and psychosocial scales completed at baseline, and 6, 12, and 18 months post programme. Qualitative research with participants and educators will explore views and experiences of the trial and preferences for methods of monitoring.

Discussion
The DESMOND SMBG trial is designed to provide evidence to inform the debate about the value of self-monitoring of blood glucose in people with newly diagnosed type 2 diabetes. Strengths include a setting in primary care, a cluster design, a health economic analysis, a comparison of different methods of monitoring while controlling for other components of training within the context of a quality assured structured education programme and a qualitative sub-study.

B-cell loss and B-cell apoptosis in human type 2 diabetes are related to islet amyloid deposition

Amyloid deposition and reduced β-cell mass are pathological hallmarks of the pancreatic islet in type 2 diabetes; however, whether the extent of amyloid deposition is associated with decreased β-cell mass is debated. We investigated the possible relationship and, for the first time, determined whether increased islet amyloid and/or decreased β-cell area quantified on histological sections is correlated with increased β-cell apoptosis. Formalin-fixed, paraffin-embedded human pancreas sections from subjects with (n = 29) and without (n = 39) diabetes were obtained at autopsy (64 ± 2 and 70 ± 4 islets/subject, respectively). Amyloid and β cells were visualized by thioflavin S and insulin immunolabeling. Apoptotic β cells were detected by colabeling for insulin and by TUNEL. Diabetes was associated with increased amyloid deposition, decreased -cell area, and increased β-cell βapoptosis, as expected. There was a strong inverse correlation between β-cell area and amyloid deposition (r=0.42, P < 0.001). β-Cell area was selectively reduced in individual amyloid-containing islets from diabetic subjects, compared with control subjects, but amyloid-free islets had β-cell area equivalent to islets from control subjects. Increased amyloid deposition was associated with β-cell apoptosis (r= 0.56, P < 0.01). Thus, islet amyloid is associated with decreased β-cell area and increased β-cell apoptosis, suggesting that islet myloid deposition contributes to the decreased β-cell mass that characterizes type 2 diabetes.

The needs, concerns and characteristics of younger Australian adults with Type 2 diabetes

Aims : The mean age of onset of Type 2 diabetes mellitus is decreasing in Australia and internationally. We conducted an internet-based survey to improve our understanding of the emotional well-being and unmet needs of younger adults with Type 2 diabetes, and to inform service provision for this group.

Methods : A random sample of National Diabetes Services Scheme registrants (n = 1,417) with Type 2 diabetes, aged 18–39 years, living in the Australian state of Victoria received an invitation to complete the online survey. The study was also advertised state-wide. The survey included validated scales (PAID-5: diabetes-related distress; WHO-5: general emotional well-being) and study-specific items. A total of 149 eligible respondents participated.

Results : Almost two-thirds (63%) of respondents reported severe-diabetes related distress; more than a quarter (27%) had impaired general emotional well-being. Most (82%) were overweight or obese (BMI ≥ 25); most (77%) had at least one other co-morbidity. Lack of motivation, feeling burned out, and being time-poor were identified as top barriers to self-management. More than half (59%) of respondents had not participated in structured diabetes education. Respondents perceived that younger adults with Type 2 diabetes had different health-care needs than their older counterparts (68%), and that most Type 2 diabetes information/services were aimed at older adults (62%). Of a range of potential new services, respondents indicated greatest interest in an online forum specifically for younger adults with Type 2 diabetes.

Conclusions : Younger adults with Type 2 diabetes have impaired emotional well-being and physical health. Population-based research is needed to confirm the current findings, to further inform service delivery and optimise outcomes for this group.

Type 2 diabetes prevalence varies by socio-economic status within and between migrant groups: analysis and implications for Australia

Background:
Ethnic diversity is increasing through migration in many developed countries. Evidence indicates that type 2 diabetes mellitus (T2DM) prevalence varies by ethnicity and socio- economic status (SES), and that in many settings, migrants experience a disproportionate burden of disease compared with locally-born groups. Given Australia’s multicultural demography, we sought to identify groups at high risk of T2DM in Victoria, Australia.

“I call it the blame and shame disease”: a qualitative study about perceptions of social stigma surrounding type 2 diabetes

Abstract
Objectives While health-related stigma has been the subject of considerable research in other conditions (obesity and HIV/AIDS), it has not received substantial attention in diabetes. The aim of the current study was to explore the social experiences of Australian adults living with type 2 diabetes mellitus (T2DM), with a particular focus on the perception and experience of diabetes-related stigma.

Design A qualitative study using semistructured interviews, which were audio recorded, transcribed and subject to thematic analysis.

Setting This study was conducted in non-clinical settings in metropolitan and regional areas in the Australian state of Victoria. Participants were recruited primarily through the state consumer organisation representing people with diabetes.

Participants All adults aged ≥18 years with T2DM living in Victoria were eligible to take part. Twenty-five adults with T2DM participated (12 women; median age 61 years; median diabetes duration 5 years).

Results A total of 21 (84%) participants indicated that they believed T2DM was stigmatised, or reported evidence of stigmatisation. Specific themes about the experience of stigma were feeling blamed by others for causing their own condition, being subject to negative stereotyping, being discriminated against or having restricted opportunities in life. Other themes focused on sources of stigma, which included the media, healthcare professionals, friends, family and colleagues. Themes relating to the consequences of this stigma were also evident, including participants’ unwillingness to disclose their condition to others and psychological distress. Participants believed that people with type 1 diabetes do not experience similar stigmatisation.

Conclusions Our study found evidence of people with T2DM experiencing and perceiving diabetes-related social stigma. Further research is needed to explore ways to measure and minimise diabetes-related stigma at the individual and societal levels, and also to explore perceptions and experiences of stigma in people with type 1 diabetes