Evolving therapeutic options for type 2 diabetes mellitus: an overview

Treatment of obesity-related diabetes: significance of thermogenic adipose tissue and targetable receptors

Diabetes mellitus is mainly classified into four types according to its pathogenesis, of which type 2 diabetes mellitus (T2DM) has the highest incidence rate and is most relevant to obesity. It is characterized by high blood glucose, which is primarily due to insulin resistance in tissues that are responsible for glucose homeostasis (such as the liver, skeletal muscle, and white adipose tissue (WAT)) combined with insufficiency of insulin secretion from pancreatic β-cells. Treatment of diabetes, especially treatment of diabetic complications (such as diabetic nephropathy), remains problematic. Obesity is one of the main causes of insulin resistance, which, however, could potentially be treated by activating thermogenic adipose tissues, like brown and beige adipose tissues, because they convert energy into heat through non-shivering thermogenesis and contribute to metabolic homeostasis. In this review, we summarize the function of certain anti-diabetic medications with known thermogenic mechanisms and focus on various receptor signaling pathways, such as previously well-known and recently discovered ones that are involved in adipose tissue-mediated thermogenesis and could be potentially targeted to combat obesity and its associated diabetes, for a better understanding of the molecular mechanisms of non-shivering thermogenesis and the development of novel therapeutic interventions for obesity-related diabetes and potentially diabetic complications.

Fucoidan from Ascophyllum nodosum Suppresses Postprandial Hyperglycemia by Inhibiting Na+/Glucose Cotransporter 1 Activity

We previously demonstrated that fucoidan with a type II structure inhibited postprandial hyperglycemia by suppressing glucose uptake, but the mechanism remains elusive. Here, we aimed to assess whether the effect of glucose absorption inhibition was related to the basic structure of fucoidans and preliminarily clarified the underlying mechanism. Fucoidans with type II structure and type I structure were prepared from Ascophyllumnodosum (AnF) or Laminariajaponica (LjF) and Kjellmaniellacrassifolia (KcF), respectively. The effects of various fucoidans on suppressing postprandial hyperglycemia were investigated using in vitro (Caco-2 monolayer model), semi-in vivo (everted gut sac model), and in vivo (oral glucose tolerance test, OGTT) assays. The results showed that only AnF with a type II structure, but not LjF or KcF with type I structure, could inhibit the glucose transport in the Caco-2 monolayer and everted gut sac models. A similar result was seen in the OGTT of Kunming mice and leptin receptor-deficient (db/db) mice, where only AnF could effectively inhibit glucose transport into the bloodstream. Furthermore, AnF (400 mg/kg/d) treatment decreased the fasting blood glucose, HbA1c, and fasting insulin levels, while increasing the serum glucagon-like peptide-1 (GLP-1) level in obese leptin receptor-deficient (db/db) mice. Furthermore, surface plasmon resonance (SPR) analysis revealed the specific binding of AnF to Na+/glucose cotransporter 1 (SGLT1), which indicated the effect of AnF on postprandial hyperglycemia could be due to its suppression on SGLT1 activity. Taken together, this study suggests that AnF with a type II structure can be a promising candidate for hyperglycemia treatment.

Characteristics of Patients with Diabetes Initiating Sodium Glucose Co-transporter-2 Inhibitors (SGLT2i): Real-World Results from Three Administrative Databases in Japan

INTRODUCTION

The aim of this study was to evaluate the characteristics of new users of sodium glucose co-transporter-2 inhibitors (SGLT2i) in comparison with those of new users of other oral antidiabetic drugs (OADs) using data retrieved from three administrative databases in Japan.

METHODS

This study included adult patients from each database who started an OAD between 2014 and 2017. Outpatients who started SGLT2i therapy were included in the SGLT2i cohort. The remaining outpatients were grouped according to the OAD class of their earliest initial prescription after no use of the index OAD during the 6-month pre-index period. Diabetes-related complications were evaluated using the Diabetes Complication Severity Index.

RESULTS

In total, 176,355 patients in the hospital-based administrative database (H-dataset), 98,361 in the pharmacy claims database (P-dataset) and 37,786 in the insurance claims database (I-dataset) were analyzed. In the H-dataset, SGLT2i users, compared with users of other OADs, tended to be younger (mean age at index: 57.7 vs. 60.3-69.2 years) and to have a higher prevalence of hypercholesterolemia (73.5 vs. 55.2-71.4%), a higher mean body weight (74.4 vs. 60.5-70.8 kg), a higher body mass index (27.6 vs. 23.5-26.4 kg/m²) and a higher glycated hemoglobin level (8.4 vs. 7.4-8.1%). There were no distinct differences in the prevalence of complications between SGLT2i users and users of other OADs in the H-dataset. Similar trends were noted in the other datasets.

CONCLUSION

Patients initiating SGLT2i therapy differed in several characteristics from new users of other OADs. SGLT2i were prescribed more frequently to younger patients, those at increased cardiovascular risk or those with poorer glycemic control.

FUNDING

Astellas Pharma Inc., Tokyo, Japan.

Kidney Disease End Points in a Pooled Analysis of Individual Patient-Level Data From a Large Clinical Trials Program of the Dipeptidyl Peptidase 4 Inhibitor Linagliptin in Type 2 Diabetes

BACKGROUND

Although assessment of cardiovascular safety is mandated by regulatory agencies for the development of new drugs to treat type 2 diabetes, evaluation of their renal safety has been relatively neglected.

STUDY DESIGN

Individual patient-level data pooled analysis of 13 phase 2 or 3 randomized, double-blind, placebo-controlled, clinical trials of the dipeptidyl peptidase 4 inhibitor linagliptin.

SETTING & PARTICIPANTS

Participants who participated in any of 13 randomized clinical trials and fulfilled predefined inclusion/exclusion criteria, such as being drug-naive (hemoglobin A1c, 7.0%-11.0% [53-97 mmol/mol]) or being on background glucose-lowering therapy (hemoglobin A1c, 6.5%-10.5% [48-91 mmol/mol]).

INTERVENTION

Of 5,466 consenting individuals with inadequately controlled type 2 diabetes, 3,505 received linagliptin, 5mg/d, and 1,961 received placebo.

OUTCOMES

The primary kidney disease outcome was defined as first occurrence during the study of 6 predefined safety end points: new onset of moderate elevation of albuminuria (urinary albumin-creatinine ratio [ACR] >30 mg/g with baseline values ≤ 30 mg/g), new onset of severe elevation of albuminuria (ACR > 300 mg/g with baseline values ≤ 300 mg/g), reduction in kidney function (serum creatinine increase to ≥250 μmol/L from a baseline value <250 μmol/L), halving of estimated glomerular filtration rate (loss of baseline eGFR >50%), acute renal failure (ascertained from diagnostic codes), or death from any cause.

MEASUREMENTS

Albuminuria was assessed using ACR. GFR was estimated using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation.

RESULTS

Cumulative exposure (person-years) was 1,751 for linagliptin and 1,055 for placebo. The primary composite outcome occurred in 448 (12.8%) and 306 (15.6%) participants in the linagliptin and placebo groups, respectively. Linagliptin treatment significantly reduced the hazard of kidney disease events by 16% compared with placebo (HR, 0.84; 95% CI, 0.72-0.97; P=0.02).

LIMITATIONS

Retrospective and hypothesis-generating study involving short- to midterm clinical trials.

CONCLUSIONS

Linagliptin was not associated with increased kidney disease risk in patients with type 2 diabetes. The potential of this drug to improve kidney disease outcomes warrants further investigation.

The impact of weight loss on weight-related quality of life and health satisfaction: results from a trial comparing canagliflozin with sitagliptin in triple therapy among people with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is primarily a self-managed disease in which self-care behaviors play an important role in achieving optimal outcomes. Because self-care does not result in immediate tangible or noticeable benefits, adherence to such a regimen can be confusing, difficult, and frustrating. People are more likely to adhere to treatment regimens that offer benefits from the patient perspective, such as convenience, avoidance of hypoglycemic episodes, and weight loss, compared with regimens that do not. In this study, we explored the impact of the average weight loss amount demonstrated with canagliflozin treatment on improvement in 3 patient-relevant outcomes that have been linked to performance of healthy behaviors and better outcomes in T2DM: weight-related quality of life, as measured by the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) questionnaire, and satisfaction with physical health and emotional health, as measured by the Current Health Satisfaction Questionnaire (CHES-Q), using data from a previously reported study. Weight loss of an amount demonstrated in clinical trials of canagliflozin was associated with improvements in weight-related quality of life and satisfaction with physical and emotional health, concepts shown to be important to the persistent and consistent performance of healthy behaviors.

Pharmacokinetic interactions between topiramate and pioglitazone and metformin

OBJECTIVE

To investigate potential drug-drug interactions between topiramate and metformin and pioglitazone at steady state.

METHODS

Two open-label studies were performed in healthy adult men and women. In Study 1, eligible participants were given metformin alone for 3 days (500 mg twice daily [BID]) followed by concomitant metformin and topiramate (titrated to 100mg BID) from days 4 to 10. In Study 2, eligible participants were randomly assigned to treatment with pioglitazone 30 mg once daily (QD) alone for 8 days followed by concomitant pioglitazone and topiramate (titrated to 96 mg BID) from days 9 to 22 (Group 1) or to topiramate (titrated to 96 mg BID) alone for 11 days followed by concomitant pioglitazone 30 mg QD and topiramate 96 mg BID from days 12 to 22 (Group 2). An analysis of variance was used to evaluate differences in pharmacokinetics with and without concomitant treatment; 90% confidence intervals (CI) for the ratio of the geometric least squares mean (LSM) estimates for maximum plasma concentration (Cmax), area under concentration-time curve for dosing interval (AUC12 or AUC24), and oral clearance (CL/F) with and without concomitant treatment were used to assess a drug interaction.

RESULTS

A comparison to historical data suggested a modest increase in topiramate oral clearance when given concomitantly with metformin. Coadministration with topiramate reduced metformin oral clearance at steady state, resulting in a modest increase in systemic metformin exposure. Geometric LSM ratios and 90% CI for metformin CL/F and AUC12 were 80% (75%, 85%) and 125% (117%, 134%), respectively. Pioglitazone had no effect on topiramate pharmacokinetics at steady state. Concomitant topiramate resulted in decreased systemic exposure to pioglitazone and its active metabolites, with geometric LSM ratios and 90% CI for AUC24 of 85.0% (75.7%, 95.6%) for pioglitazone, 40.5% (36.8%, 44.6%) for M-III, and 83.8% (76.1%, 91.2%) for M-IV, respectively. This effect appeared more pronounced in women than in men. Coadministration of topiramate with metformin or pioglitazone was generally well tolerated by healthy participants in these studies.

CONCLUSIONS

A modest increase in metformin exposure and decrease in topiramate exposure was observed at steady state following coadministration of metformin 500 mg BID and topiramate 100mg BID. The clinical significance of the observed interaction is unclear but is not likely to require a dose adjustment of either agent. Pioglitazone 30 mg QD did not affect the pharmacokinetics of topiramate at steady state, while coadministration of topiramate 96 mg BID with pioglitazone decreased steady-state systemic exposure to pioglitazone, M-III, and M-IV. While the clinical consequence of this interaction is unknown, careful attention should be given to the routine monitoring for adequate glycemic control of patients receiving this concomitant therapy. Concomitant administration of topiramate with metformin or pioglitazone was generally well tolerated and no new safety concerns were observed.

Diabetes mellitus and suicide

Relationship of diabetes mellitus (DM) with metal health disorders such as depression has been explored extensively in the published literatures. However, association of diabetes mellitus with suicidal tendencies has been evaluated less extensively. The present narrative review aimed to assess the literature relating to diabetes mellitus and suicide. As a part of the review, Pubmed and Google Scholar databases were searched for English language peer reviewed published studies with keywords relating to diabetes and suicide. Additional references were identified using cross-references. The available literature suggests that suicidal ideas and attempts are more frequent in patients with diabetes mellitus than healthy or medically ill controls. Although, a few studies report evidence to the contrary. Suicide accounts for a large proportion of deaths in patients with diabetes mellitus type I (T1DM), and their mortality rate is higher than that of age matched control population. Psychological morbidity, including depression, precedes suicidal ideas and attempts; though many other factors can be hypothesized to impact and modulate this association. A common method of suicide attempt in patients with diabetes includes uses of high doses of insulin and its congeners or medications to treat the disease. Regular screening and prompt treatment of depression and suicidality is suggested for patients with DM.

Glucose turnover after replacement of usual therapy by insulin in insulin-naive type 2 diabetes subjects

CONTEXT

Discontinuation of anti-hyperglycemic oral agents and initiation of insulin is recommended in certain clinical situations for inpatients with type 2 diabetes (T2D). The effects on glucose turnover when these agents are acutely withdrawn are poorly understood and may be of importance when insulin therapy is initiated.

OBJECTIVE

Our objective was to investigate alterations in glucose turnover after acute withdrawal of noninsulin therapy.

DESIGN AND SETTING

This was a randomized crossover study at a clinical research facility.

PARTICIPANTS

Participants included 12 insulin-naive subjects with T2D.

METHODS

Subjects attended two 24-hour visits. Standard therapy was discontinued and replaced by closed-loop insulin delivery during the intervention visit. Usual anti-hyperglycemic therapy was continued during the control visit. Systemic glucose appearance (Ra) and glucose disposal (Rd) were measured using a tracer dilution technique with iv [6,6-(2)H2]glucose.

RESULTS

Plasma glucose profiles during both visits were comparable (P = .48). Glucose Ra increased during the day (21.4 [19.5, 23.5] vs 18.6 [17.0, 21.6) μmol/kg/min, P = .019) and decreased overnight (9.7 [8.5, 11.4] vs 11.6 [10.3, 12.9] μmol/kg/min, P = .004) when the usual therapy was discontinued and replaced with insulin. Increased daytime glucose Rd (21.2 [19.4, 23.9] vs 18.8 [18.3, 21.7] μmol/kg/min, P = .002) and decreased overnight Rd (10.4 [9.1, 12.0] vs 11.8 [10.7, 13.7] μmol/kg/min, P = .005) were observed when the usual therapy was discontinued, whereas daytime peripheral insulin sensitivity was reduced (47.8 [24.8, 66.1] vs 62.5 [34.8, 75.8] nmol/kg/min per pmol/L, P = .034).

CONCLUSION

In T2D, acute discontinuation of anti-hyperglycemic therapy and replacement with insulin increases postprandial Ra and reduces peripheral insulin sensitivity. Insulin dose initiation may need to compensate for these alterations.

Periprocedural glycemic control in patients with diabetes mellitus undergoing coronary angiography with possible percutaneous coronary intervention

Periprocedural hyperglycemia is an independent predictor of mortality in patients who underwent percutaneous coronary intervention (PCI). However, periprocedural management of blood glucose is not standardized. The effects of routinely continuing long-acting glucose-lowering medications before coronary angiography with possible PCI on periprocedural glycemic control have not been investigated. Patients with diabetes mellitus (DM; n = 172) were randomized to continue (Continue group; n = 86) or hold (Hold group; n = 86) their clinically prescribed long-acting glucose-lowering medications before the procedure. The primary end point was glucose level on procedural access. In a subset of patients (no DM group: n = 25; Continue group: n = 25; and Hold group: n = 25), selected measures of platelet activity that change acutely were assessed. Patients with DM randomized to the Continue group had lower blood glucose levels on procedural access compared with those randomized to the Hold group (117 [97 to 151] vs 134 [117 to 172] mg/dl, p = 0.002). There were two hypoglycemic events in the Continue group and none in the Hold group, and no adverse events in either group. Selected markers of platelet activity differed across the no DM, Continue, and Hold groups (leukocyte platelet aggregates: 8.1% [7.2 to 10.4], 8.7% [6.9 to 11.4], 10.9% [8.6 to 14.7], p = 0.007; monocyte platelet aggregates: 14.0% [10.3 to 16.3], 20.8% [16.2 to 27.0], 22.5% [15.2 to 35.4], p <0.001; soluble p-selectin: 51.9 ng/ml [39.7 to 74.0], 59.1 ng/ml [46.8 to 73.2], 72.2 ng/ml [58.4 to 77.4], p = 0.014). In conclusion, routinely continuing clinically prescribed long-acting glucose-lowering medications before coronary angiography with possible PCI help achieve periprocedural euglycemia, appear safe, and should be considered as a strategy for achieving periprocedural glycemic control.

Hepatitis C virus infection and insulin resistance

Approximately 170 million people worldwide are chronically infected with hepatitis C virus (HCV). Chronic HCV infection is the leading cause for the development of liver fibrosis, cirrhosis, hepatocellular carcinoma (HCC) and is the primary cause for liver transplantation in the western world. Insulin resistance is one of the pathological features in patients with HCV infection and often leads to development of type II diabetes. Insulin resistance plays an important role in the development of various complications associated with HCV infection. Recent evidence indicates that HCV associated insulin resistance may result in hepatic fibrosis, steatosis, HCC and resistance to anti-viral treatment. Thus, HCV associated insulin resistance is a therapeutic target at any stage of HCV infection. HCV modulates normal cellular gene expression and interferes with the insulin signaling pathway. Various mechanisms have been proposed in regard to HCV mediated insulin resistance, involving up regulation of inflammatory cytokines, like tumor necrosis factor-α, phosphorylation of insulin-receptor substrate-1, Akt, up-regulation of gluconeogenic genes like glucose 6 phosphatase, phosphoenolpyruvate carboxykinase 2, and accumulation of lipid droplets. In this review, we summarize the available information on how HCV infection interferes with insulin signaling pathways resulting in insulin resistance.