Comparison of the Effects of Various Antidiabetic Medication on Bone Mineral Density in Patients with Type 2 Diabetes Mellitus

The effect of antidiabetic drugs on bone metabolism: a concise review

Diabetes mellitus (DM) is a complex metabolic disorder characterized by chronic hyperglycemia, which derives from either insufficient insulin production [type 1 diabetes mellitus (T1DM)] or both impaired insulin sensitivity along with inadequate insulin production [type 2 diabetes mellitus (T2DM)] and affects millions of people worldwide. In addition to the adverse effects of DM on classical target organs and tissues, skeletal health can also be adversely affected. There is considerable evidence linking DM with osteoporosis. The fracture risk in patients with DM differs upon the type of diabetes, and it appears to be related to the type of anti-diabetic treatment. Antidiabetic drugs may have various effects on bone health. Most of them have neutral or even favorable effects on bone metabolism with the exception of thiazolidinediones (TZDs). Some studies suggest that TZDs may have negative impact on bone health by decreasing bone formation and increasing the fracture risk. There are also limited studies linking the use of canagliflozin, a Sodium-glucose contransporter-2 inhibitor (SGLT2i), with increased fracture risk. On the other hand, therapies that are based on incretin effect, like Dipeptidyl peptidase-4 inhibitors (DPP-4i) and Glucagon-like peptide-1 receptor agonizts (GLP-1RAs) might have positive effects on bone health by promoting bone formation. Herein we review the impact of antidiabetic drugs on bone health, highlighting the potential benefits and risks associated with these medications in an attempt to contribute to the development of personalized treatment strategies for individuals with DM.

Dapagliflozin Improves High-Fat Diet-Induced Cognitive Impairment in Female Mice

BACKGROUND

High fat consumption is a known risk factor for the development of type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD). Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have been found to possess anti-inflammatory and neuroprotective properties. However, the cognitive effects and mechanisms of SGLT2is on female mice fed with a high-fat diet remain unknown.

OBJECTIVE

This study aimed to investigate the impacts of dapagliflozin on metabolism, cognition, neuroinflammation, insulin resistance, and microglial activation in female mice fed a HFD.

METHODS

Dapagliflozin (1 mg/kg) was administered to HFD-fed mice for 24 weeks. Body weight, glucose tolerance, and insulin resistance were assessed. Additionally, all mice were subjected to the Morris water maze (MWM) and one-trial Y-maze tests. The levels of metabolic hormones and cytokines were analyzed using ELISA kits. The levels of phosphorylated tau (p-tau) protein in the hippocampus were measured. Microglia, insulin receptors, NLRP3, and IL-1β in the hippocampus of mice were evaluated by immunofluorescence or immunohistochemical staining.

RESULTS

As anticipated, dapagliflozin improved insulin resistance and glucose metabolism and reduced cognitive impairment in female mice fed with a HFD. In the hippocampus, dapagliflozin alleviated microglial activation yet did not reduce the secretion of inflammatory chemokines. Furthermore, it increased the expression of insulin receptor in the hippocampus of HFD-fed mice and decreased the expression of p-tau.

CONCLUSIONS

Our results provide a foundation for the clinical application of SGLT2is as an adjuvant to slow down the progression of central degenerative diseases related to metabolic disorders, such as AD.

The multiple actions of dipeptidyl peptidase 4 (DPP-4) and its pharmacological inhibition on bone metabolism: a review

BACKGROUND

Dipeptidyl peptidase 4 (DPP-4) plays a crucial role in breaking down various substrates. It also has effects on the insulin signaling pathway, contributing to insulin resistance, and involvement in inflammatory processes like obesity and type 2 diabetes mellitus. Emerging effects of DPP-4 on bone metabolism include an inverse relationship between DPP-4 activity levels and bone mineral density, along with an increased risk of fractures.

MAIN BODY

The influence of DPP-4 on bone metabolism occurs through two axes. The entero-endocrine-osseous axis involves gastrointestinal substrates for DPP-4, including glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptides 1 (GLP-1) and 2 (GLP-2). Studies suggest that supraphysiological doses of exogenous GLP-2 has a significant inhibitory effect on bone resorption, however the specific mechanism by which GLP-2 influences bone metabolism remains unknown. Of these, GIP stands out for its role in bone formation. Other gastrointestinal DPP-4 substrates are pancreatic peptide YY and neuropeptide Y-both bind to the same receptors and appear to increase bone resorption and decrease bone formation. Adipokines (e.g., leptin and adiponectin) are regulated by DPP-4 and may influence bone remodeling and energy metabolism in a paracrine manner. The pancreatic-endocrine-osseous axis involves a potential link between DPP-4, bone, and energy metabolism through the receptor activator of nuclear factor kappa B ligand (RANKL), which induces DPP-4 expression in osteoclasts, leading to decreased GLP-1 levels and increased blood glucose levels. Inhibitors of DPP-4 participate in the pancreatic-endocrine-osseous axis by increasing endogenous GLP-1. In addition to their glycemic effects, DPP-4 inhibitors have the potential to decrease bone resorption, increase bone formation, and reduce the incidence of osteoporosis and fractures. Still, many questions on the interactions between DPP-4 and bone remain unanswered, particularly regarding the effects of DPP-4 inhibition on the skeleton of older individuals.

CONCLUSION

The elucidation of the intricate interactions and impact of DPP-4 on bone is paramount for a proper understanding of the body's mechanisms in regulating bone homeostasis and responses to internal stimuli. This understanding bears significant implications in the investigation of conditions like osteoporosis, in which disruptions to these signaling pathways occur. Further research is essential to uncover the full extent of DPP-4's effects on bone metabolism and energy regulation, paving the way for novel therapeutic interventions targeting these pathways, particularly in older individuals.

Bone Loss in Diabetes Mellitus: Diaporosis

The objective of this review is to examine the connection between osteoporosis and diabetes, compare the underlying causes of osteoporosis in various forms of diabetes, and suggest optimal methods for diagnosing and assessing fracture risk in diabetic patients. This narrative review discusses the key factors contributing to the heightened risk of fractures in individuals with diabetes, as well as the shared elements impacting the treatment of both diabetes mellitus and osteoporosis. Understanding the close link between diabetes and a heightened risk of fractures is crucial in effectively managing both conditions. There are several review articles of meta-analysis regarding diaporosis. Nevertheless, no review articles showed collected and well-organized medications of antidiabetics and made for inconvenient reading for those who were interested in details of drug mechanisms. In this article, we presented collected and comprehensive charts of every antidiabetic medication which was linked to fracture risk and indicated plausible descriptions according to research articles.

A multicentre, double-blind, placebo-controlled, randomized, parallel comparison, phase 3 trial to evaluate the efficacy and safety of pioglitazone add-on therapy in type 2 diabetic patients treated with metformin and dapagliflozin

AIM

To investigate the efficacy and safety of pioglitazone compared to placebo when added to metformin plus dapagliflozin, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, for patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

In a multicentre study, with a randomized, double-blind, placebo-controlled design, 249 Korean patients with T2DM suboptimally managed on metformin and dapagliflozin were assigned to receive either pioglitazone (15 mg daily) or placebo for 24 weeks, followed by a 24-week pioglitazone extension. Primary outcomes included changes in glycated haemoglobin (HbA1c), with secondary outcomes assessing insulin resistance, adiponectin levels, lipid profiles, liver enzymes, body weight and waist circumference.

RESULTS

Pioglitazone administration resulted in a significant reduction in HbA1c levels (from 7.80% ± 0.72% to 7.27% ± 0.82%) compared with placebo (from 7.79% ± 0.76% to 7.69% ± 0.86%, corrected mean difference: -0.42% ± 0.08%; p < 0.01) at 24 weeks. Additional benefits from pioglitazone treatment included enhanced insulin sensitivity, increased adiponectin levels, raised high-density lipoprotein cholesterol levels and reduced liver enzyme levels, resulting in improvement in nonalcoholic fatty liver disease liver fat score. Despite no serious adverse events in either group, pioglitazone therapy was modestly but significantly associated with weight gain and increased waist circumference.

CONCLUSIONS

Adjunctive pioglitazone treatment in T2DM inadequately controlled with metformin and dapagliflozin demonstrates considerable glycaemic improvement, metabolic benefits, and a low risk of hypoglycaemia. These advantages must be weighed against the potential for weight gain and increased waist circumference.

Meta-Analysis on the Association Between DPP-4 Inhibitors and Bone Mineral Density and Osteoporosis

Background Type 2 Diabetes Mellitus (T2DM) frequently coexists with osteoporosis and reduced bone mineral density (BMD). Dipeptidyl peptidase-4 inhibitors (DPP-4i), a class of antihyperglycemic agents, are commonly employed in T2DM treatment. However, the influence of DPP-4i on bone health remains unclear and debated. This meta-analysis is conducted to explore the relationship between the use of DPP-4i and changes in BMD, as well as the prevalence of osteoporosis among T2DM patients. Methods We conducted a comprehensive search in PubMed, Embase, and Cochrane Library and Web of Science databases for relevant studies published up until June 2023. Studies included in the meta-analysis were those investigating T2DM patients under DPP-4i treatment, and examining the effects on BMD and osteoporosis. Random-effects models and fixed-effect models were utilized to compute the pooled effects. Heterogeneity among the included studies was evaluated using I² statistics. Results This meta-analysis incorporated a total of 10 studies, encompassing a combined population of 214,541 individuals. The results from this meta-analysis indicated an increase in BMD following DPP-4i usage (SMD 0.15, 95 % confidence interval 0.03-0.26). Additionally, the risk of osteoporosis was significantly reduced (OR 0.90, 95 % confidence interval 0.86-0.94) with very low heterogeneity, recorded at 0 % and 53.0 % respectively. No publication bias was detected in the funnel plot, and sensitivity analyses affirmed the stability of the study's conclusions. Conclusion Our results offer valuable insights into the positive impact of DPP-4i on bone health in T2DM patients, contributing to informed clinical decision-making. These findings may inform the development of more comprehensive T2DM management strategies that account for bone health.

Complementary effects of dapagliflozin and lobeglitazone on metabolism in a diet-induced obese mouse model

Thiazolidinedione, an insulin sensitizer, has beneficial effects on glucose metabolism; however, there are concerns regarding weight gain and heart failure. Sodium-glucose co-transporter 2 (SGLT2) inhibitors can reduce body weight, increase diuresis, and play a protective role in heart failure. We examined the complementary effects of dapagliflozin, an SGLT2 inhibitor, and lobeglitazone, a thiazolidinedione, in high-fat diet (HFD)-induced obese mice. We treated HFD-induced obese mice with vehicle, dapagliflozin, lobeglitazone, and their combination for 12 weeks. Oral glucose tolerance and insulin tolerance tests were performed after 12-week treatment, and body composition was measured by dual-energy X-ray absorptiometry before and after treatment. We analyzed oxygen consumption rate (OCR) using 3T3-L1 cells after treatment of β-hydroxybutyrate and/or lobeglitazone. Treatment with a combination of dapagliflozin and lobeglitazone resulted in a significant decrease in postprandial hyperglycemia compared with dapagliflozin monotherapy, but not compared with lobeglitazone monotherapy. The addition of dapagliflozin to lobeglitazone treatment did not attenuate weight gain compared with lobeglitazone monotherapy in this study. However, this combination prevented the increase of organ weight of liver and heart, and OCR in 3T3-L1 cells was increased after treatment with a combination of β-hydroxybutyrate and lobeglitazone compared to lobeglitazone monotherapy. We confirmed the beneficial effect of lobeglitazone on glucose metabolism; however, we did not find any beneficial effect of dapagliflozin on body weight in HFD-induced obese mice. However, the protective effects of dapagliflozin and lobeglitazone combined therapy on the liver, heart, energy consumption, and β-cell senescence are worth investigating in clinical trials.

Association of Bone Turnover Markers with Type 2 Diabetes Mellitus and Microvascular Complications: A Matched Case-Control Study

Purpose

The aim of this study was to evaluate the association of bone turnover markers (BTMs) with type 2 diabetes mellitus (T2DM) and microvascular complications.

Methods

A total of 166 T2DM patients and 166 non-diabetic controls matched by gender and age were enrolled. T2DM patients were sub-classified into groups based on whether they had diabetic peripheral neuropathy (DPN), diabetic retinopathy (DR), and diabetic kidney disease (DKD). Clinical data including demographic characteristics and blood test results [serum levels of osteocalcin (OC), N-terminal propeptide of type 1 procollagen (P1NP), and β-crosslaps (β-CTX)] were collected. Logistic regression and restrictive cubic spline curves were performed to examine the association of BTMs with the risk of T2DM and microvascular complications.

Results

After adjusting for family history of diabetes, sex and age, an inverse association was observed between elevated serum OC levels [O, p < 0.001] and increased serum P1NP levels , p < 0.001] with the risk of T2DM. Moreover, there was an inverse linear association of serum OC and P1NP levels with the risk of T2DM. However, β-CTX was not associated with T2DM. Further analysis showed a nonlinear association between OC and the risk of DR, while P1NP and β-CTX were not correlated with DR. Serum concentrations of BTMs were not associated with the risks of DPN and DKD.

Conclusion

Serum OC and P1NP levels were negatively correlated with T2DM risk. Particularly, serum OC levels were associated with DR risk. Given that BTMs are widely used as markers of bone remodeling, the present finding provides a new perspective for estimating the risk of diabetic microvascular complications.