Exploring treatment strategies for type 2 diabetes

V(v)-Schiff base species induce adipogenesis through structure-specific influence of genetic targets

Appropriately designed Schiff-base substrates enhance V(v)-bioavailability and insulin-mimetic biomolecular gene profiling, inducing adipogenesis in a structure-specific manner.

Diabetes and its link with cancer: providing the fuel and spark to launch an aggressive growth regime

Diabetes is a disease involving metabolic derangements in multiple organs. While the spectrum of diabetic complications has been known for years, recent evidence suggests that diabetes could also contribute to the initiation and propagation of certain cancers. The mechanism(s) underlying this relationship are not completely resolved but likely involve changes in hormone and nutrient levels, as well as activation of inflammatory and stress-related pathways. Interestingly, some of the drugs used clinically to treat diabetes also appear to have antitumour effects, further highlighting the interaction between these two conditions. In this contribution we review recent literature on this emerging relationship and explore the potential mechanisms that may promote cancer in diabetic patients.

Current role of short-term intensive insulin strategies in newly diagnosed type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a progressive disease characterized by worsening insulin resistance and a decline in β-cell function. Achieving good glycemic control becomes more challenging as β-cell function continues to deteriorate throughout the disease process. The traditional management paradigm emphasizes a stepwise approach, and insulin has generally been reserved as a final armament. However, mounting evidence indicates that short-term intensive insulin therapy used in the early stages of type 2 diabetes could improve β-cell function, resulting in better glucose control and more extended glycemic remission than oral antidiabetic agents. Improvements in insulin sensitivity and lipid profile were also seen after the early initiation of short-term intensive insulin therapy. Thus, administering short-term intensive insulin therapy to patients with newly diagnosed T2DM has the potential to delay the natural process of this disease, and should be considered when clinicians initiate treatment. Although the early use of insulin is advocated by some guidelines, the optimal time to initiate insulin therapy is not clearly defined or easily recognized, and a pragmatic approach is lacking. Herein we summarize the current understanding of early intensive insulin therapy in patients with newly diagnosed T2DM, focusing on its clinical benefit and problems, as well as possible biological mechanisms of action, and discuss our perspective.

Initial combination with linagliptin and metformin in newly diagnosed type 2 diabetes and severe hyperglycemia

Making appropriate treatment decisions for patients newly diagnosed with type 2 diabetes mellitus (T2DM) and severe hyperglycemia (glycated hemoglobin [HbA1c]>10% or fasting plasma glucose≥250 mg/dL) presents a formidable challenge to primary care physicians. Extreme defects in insulin secretion make it unlikely that these patients will achieve glycemic targets with metformin monotherapy. Additionally, uncontrolled hyperglycemia is associated with an increased risk of short-term acute complications, such as hyperosmolar coma, and long-term complications affecting the micro- and macrovasculature. Thus, severely hyperglycemic patients require prompt, intensive treatment to re-establish glycemic control. Current guidelines indicate that either initial insulin therapy or initial combination therapy with metformin plus non-insulin drug(s) are the treatments of choice for these challenging-to-treat patients. This mini-review examines the clinical evidence supporting these two treatment options, with particular reference to the findings of a phase 3 study of treatment with an initial combination of metformin plus the dipeptidyl peptidase-4 inhibitor, linagliptin. Intensive insulin therapy can induce sustained euglycemia and improve beta-cell function in newly diagnosed patients. However, insulin use is associated with an increased risk of adverse events, such as hypoglycemia and weight gain. These potentially serious side effects cause concern among patients and physicians, and are a major barrier to initiating and maintaining adherence to insulin treatment. In the phase 3 study, open-label treatment of severely hyperglycemic patients (HbA1c≥11.0%) with linagliptin plus metformin resulted in a mean change in HbA1c of -3.7%±1.7%. This combination therapy was generally well tolerated with most adverse events being of mild or moderate intensity; asymptomatic hypoglycemia was reported by just 1 of 66 (1.5%) patients. These findings provide evidence in support of linagliptin plus metformin as a well-tolerated and effective treatment alternative to insulin for new-onset patients with T2DM and severe hyperglycemia.

Plasma profiles of glucose, insulin and lipids in the male WBN/Kob-Lepr(fa) rat, a new model of type 2 diabetes with obesity

Plasma profiles of glucose, insulin and lipids were examined in the male WBN/Kob-Lepr(fa) (fa/fa) rat, a new model of type 2 diabetes (T2D), in comparison with age-matched original male WBN/Kob (lean) rats. The fa/fa rats developed hypertriglycemia, obesity and hyperglycemia from 5, 7, and 9 weeks of age, respectively. Plasma insulin levels in fa/fa rats were significantly higher than those in lean rats at 5 weeks of age, but after 11 weeks of age gradually declined to the levels in lean rats. HOMA-IR, a measure of insulin resistance status, showed that fa/fa rats had insulin resistance. The fa/fa rat has the potential to become an important animal model of T2D with obesity.

Recovery of β-cell functions with low-dose insulin therapy: study in newly diagnosed type 2 diabetes mellitus patients

AIM

Insulin therapy induces remission in subjects with newly diagnosed type 2 diabetes mellitus (T2DM). This study assessed the insulin and C-peptide levels in newly diagnosed T2DM subjects during low-dose insulin therapy.

SUBJECTS AND METHODS

Twenty newly diagnosed, drug-naive, T2DM patients without acute or chronic complications were the subjects for this study. Premixed insulin (70/30), 16 units, as two divided doses, was started for all subjects after preliminary investigations. The same dose of insulin was continued until normoglycemia was achieved. Subsequently the insulin dose was down-titrated. Plasma insulin, C-peptide, and blood glucose (both fasting and after breakfast) were measured at baseline and monthly for 6 months. Body weight and glycosylated hemoglobin (HbA1c) were measured every 3 months and the lipid profile was obtained at baseline and at 6 months.

RESULTS

Blood glucose levels showed a rapid decreasing trend and reached the near-normoglycemic range by 3 months, whereas plasma insulin and C-peptide showed a slow and steady increase until the fourth month and remained the same during the next 2 months of follow-up. HbA1c was 11.3 ± 1.4% (range, 8.6-13.5%) and 7.05 ± 0.54% (range, 6.3-8.1%) at the time of diagnosis and at the end of 6 months, respectively. The mean weights of the study subjects at baseline and 3 and 6 months were 70 ± 16 kg (range, 44-95 kg), 68 ± 13 kg, and 68 ± 13 kg (P = 0.083), respectively. Total cholesterol, low-density lipoprotein-cholesterol, and triglycerides decreased, whereas high-density lipoprotein-cholesterol was higher at 6 months.

CONCLUSION

Low-dose insulin therapy in newly diagnosed T2DM leads to β-cell recovery (as documented by plasma insulin and C-peptide levels) by 3-4 months.

Glycemic variability correlates strongly with postprandial beta-cell dysfunction in a segment of type 2 diabetic patients using oral hypoglycemic agents

OBJECTIVE

Glucose fluctuations trigger activation of oxidative stress, a main mechanism leading to secondary diabetes complications. We evaluated the relationship between glycemic variability and beta-cell dysfunction.

RESEARCH DESIGN AND METHODS

We conducted a cross-sectional study in 59 patients with type 2 diabetes (aged 64.2 +/- 8.6 years, A1C 6.5 +/- 1.0%, and BMI 29.8 +/- 3.8 kg/m(2)[mean +/- SD]) using either oral hypoglycemic agents (OHAs) (n = 34) or diet alone (nonusers). As a measure of glycemic variability, the mean amplitude of glycemic excursions (MAGE) was computed from continuous glucose monitoring data recorded over 3 consecutive days. The relationships between MAGE, beta-cell function, and clinical parameters were assessed by including postprandial beta-cell function (PBCF) and basal beta-cell function (BBCF) obtained by a model-based method from plasma C-peptide and plasma glucose during a mixed-meal test as well as homeostasis model assessment of insulin sensitivity, clinical factors, carbohydrate intake, and type of OHA.

RESULTS

MAGE was nonlinearly correlated with PBCF (r = 0.54, P < 0.001) and with BBCF (r = 0.31, P = 0.025) in OHA users but failed to correlate with these parameters in nonusers (PBCF P = 0.21 and BBCF P = 0.07). The stepwise multiple regression analysis demonstrated that PBCF and OHA combination treatment were independent contributors to MAGE (R(2) = 0.50, P < 0.010), whereas insulin sensitivity, carbohydrate intake, and nonglycemic parameters failed to contribute.

CONCLUSIONS

PBCF appears to be an important target to reduce glucose fluctuations in OHA-treated type 2 diabetes.

Beneficial effects of insulin on glycemic control and beta-cell function in newly diagnosed type 2 diabetes with severe hyperglycemia after short-term intensive insulin therapy

OBJECTIVE

To evaluate whether treatment with insulin is advantageous compared with oral antidiabetes agents in newly diagnosed type 2 diabetes with severe hyperglycemia after short-term intensive insulin therapy.

RESEARCH DESIGN AND METHODS

Newly diagnosed type 2 diabetic patients with severe hyperglycemia were hospitalized and treated with intensive insulin injections for 10-14 days. The oral glucose tolerance test (OGTT) was performed after intensive insulin treatment. After discharge, the patients were randomized to receive either insulin injections or oral antidiabetes drugs (OADs) for further management. The OGTT was repeated 6 months later, and beta-cell function and insulin sensitivity were evaluated again. These subjects were continually followed up for another 6 months to evaluate their long-term glycemic control.

RESULTS

At the 6th month of the study, the A1C level was significantly lower in the insulin group than in the OAD group (6.33 +/- 0.70% vs. 7.50 +/- 1.50%; P = 0.002). During the follow-up visit, the A1C level was still better in the insulin group (6.78 +/- 1.21% vs. 7.84 +/- 1.74%; P = 0.009). All parameters regarding beta-cell function measured in the OGTT were improved significantly in both groups after 6 months of treatment. Compared with the OAD group, the homeostasis model assessment of beta-cell function index, insulin area under the curve, and insulinogenic index were better in the insulin group.

CONCLUSIONS

A 6-month course of insulin therapy, compared with OAD treatment, could more effectively achieve adequate glycemic control and significant improvement of beta-cell function in new-onset type 2 diabetic patients with severe hyperglycemia.

Effect of intensive insulin therapy on beta-cell function and glycaemic control in patients with newly diagnosed type 2 diabetes: a multicentre randomised parallel-group trial

BACKGROUND

Early intensive insulin therapy in patients with newly diagnosed type 2 diabetes might improve beta-cell function and result in extended glycaemic remissions. We did a multicentre, randomised trial to compare the effects of transient intensive insulin therapy (continuous subcutaneous insulin infusion [CSII] or multiple daily insulin injections [MDI]) with oral hypoglycaemic agents on beta-cell function and diabetes remission rate.

METHODS

382 patients, aged 25-70 years, were enrolled from nine centres in China between September, 2004, and October, 2006. The patients, with fasting plasma glucose of 7.0-16.7 mmol/L, were randomly assigned to therapy with insulin (CSII or MDI) or oral hypoglycaemic agents for initial rapid correction of hyperglycaemia. Treatment was stopped after normoglycaemia was maintained for 2 weeks. Patients were then followed-up on diet and exercise alone. Intravenous glucose tolerance tests were done and blood glucose, insulin, and proinsulin were measured before and after therapy withdrawal and at 1-year follow-up. Primary endpoint was time of glycaemic remission and remission rate at 1 year after short-term intensive therapy. Analysis was per protocol. This study was registered with ClinicalTrials.gov, number NCT00147836.

FINDINGS

More patients achieved target glycaemic control in the insulin groups (97.1% [133 of 137] in CSII and 95.2% [118 of 124] in MDI) in less time (4.0 days [SD 2.5] in CSII and 5.6 days [SD 3.8] in MDI) than those treated with oral hypoglycaemic agents (83.5% [101 of 121] and 9.3 days [SD 5.3]). Remission rates after 1 year were significantly higher in the insulin groups (51.1% in CSII and 44.9% in MDI) than in the oral hypoglycaemic agents group (26.7%; p=0.0012). beta-cell function represented by HOMA B and acute insulin response improved significantly after intensive interventions. The increase in acute insulin response was sustained in the insulin groups but significantly declined in the oral hypoglycaemic agents group at 1 year in all patients in the remission group.

INTERPRETATION

Early intensive insulin therapy in patients with newly diagnosed type 2 diabetes has favourable outcomes on recovery and maintenance of beta-cell function and protracted glycaemic remission compared with treatment with oral hypoglycaemic agents.