Effect of anti-diabetic drugs on bone metabolism: Evidence from preclinical and clinical studies

A comprehensive meta-analysis on the association of SGLT2is and GLP-1RAs with vascular diseases, digestive diseases and fractures

AIM

Sodium-glucose cotransporter-2 inhibitors (SGLT2is) and glucagon-like peptide 1 receptor agonists (GLP-1RAs) are two new classes of antidiabetic agents. We aimed to evaluate the association between these two drug classes and risk of various vascular diseases, digestive diseases and fractures.

METHODS

Large randomized trials of SGLT2is and GLP-1RAs were included. Outcomes of interest were the various serious adverse events related to vascular diseases, digestive diseases and fractures. We performed meta-analyses using synthesize risk ratio (RR) and 95% confidence interval (CI) as effect size.

RESULTS

We included 27 large trials. SGLT2is had significant association with less hypertension (RR 0.70, 95% CI 0.54-0.91), hypertensive crisis (RR 0.63, 95% CI 0.47-0.84), varicose vein (RR 0.34, 95% CI 0.13-0.92), and vomiting (RR 0.55, 95% CI 0.31-0.97); but more spinal compression fracture (RR 1.73, 95% CI 1.02-2.92) and tibia fracture. GLP-1RAs had significant association with more deep vein thrombosis (RR 1.92, 95% CI 1.23-3.00), pancreatitis (RR 1.54, 95% CI 1.07-2.22), and cholecystitis acute (RR 1.51, 95% CI 1.08-2.09); but less rib fracture (RR 0.59, 95% CI 0.35-0.97). Sensitivity analyses suggested that our findings were robust.

CONCLUSIONS

SGLT2is may have protective effects against specific vascular and digestive diseases, whereas they may increase the incidence of site-specific fractures (e.g., spinal compression fracture). GLP-1RAs may have protective effects against site-specific fractures (i.e., rib fracture), whereas they may increase the incidence of specific vascular and digestive diseases. These findings may help to make a choice between SGLT2is and GLP-1RAs in clinical practice.

Exploration of the Shared Hub Genes and Biological Mechanism in Osteoporosis and Type 2 Diabetes Mellitus based on Machine Learning

A substantial amount of evidence suggests a close relationship between osteoporosis (OP) and Type 2 Diabetes Mellitus (T2DM), but the mechanisms involved remain unknown. Therefore, we conducted this study with the aim of screening for hub genes common to both diseases and conducting a preliminary exploration of common regulatory mechanisms. In the present study, we first screened genes significantly associated with OP and T2DM by the univariate logistic regression algorithm. And then, based on cross-analysis and random forest algorithm, we obtained three hub genes (ACAA2, GATAD2A, and VPS35) and validated the critical roles and predictive performance of the three genes in both diseases by differential expression analysis, receiver operating characteristic (ROC) curves, and genome wide association study (GWAS) analysis. Finally, based on gene set enrichment analysis (GSEA) and the construction of the miRNA-mRNA regulatory network, we conducted a preliminary exploration of the co-regulatory mechanisms of three hub genes in two diseases. In conclusion, this study provides promising biomarkers for predicting and treating both diseases and offers novel directions for exploring the common regulatory mechanisms of both diseases.

Unlocking the Full Potential of SGLT2 Inhibitors: Expanding Applications beyond Glycemic Control

The number of diabetic patients has risen dramatically in recent decades, owing mostly to the rising incidence of type 2 diabetes mellitus (T2DM). Several oral antidiabetic medications are used for the treatment of T2DM including, α-glucosidases inhibitors, biguanides, sulfonylureas, meglitinides, GLP-1 receptor agonists, PPAR-γ agonists, DDP4 inhibitors, and SGLT2 inhibitors. In this review we focus on the possible effects of SGLT2 inhibitors on different body systems. Beyond the diabetic state, SGLT2 inhibitors have revealed a demonstrable ability to ameliorate cardiac remodeling, enhance myocardial function, and lower heart failure mortality. Additionally, SGLT2 inhibitors can modify adipocytes and their production of cytokines, such as adipokines and adiponectin, which enhances insulin sensitivity and delays diabetes onset. On the other hand, SGLT2 inhibitors have been linked to decreased total hip bone mineral deposition and increased hip bone resorption in T2DM patients. More data are needed to evaluate the role of SGLT2 inhibitors on cancer. Finally, the effects of SGLT2 inhibitors on neuroprotection appear to be both direct and indirect, according to scientific investigations utilizing various experimental models. SGLT2 inhibitors improve vascular tone, elasticity, and contractility by reducing oxidative stress, inflammation, insulin signaling pathways, and endothelial cell proliferation. They also improve brain function, synaptic plasticity, acetylcholinesterase activity, and reduce amyloid plaque formation, as well as regulation of the mTOR pathway in the brain, which reduces brain damage and cognitive decline.

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.

Diabetic bone regeneration with nanoceria-tailored scaffolds by recapitulating cellular microenvironment: Activating integrin/TGF-β co-signaling of MSCs while relieving oxidative stress

Regenerating defective bone in patients with diabetes mellitus remains a significant challenge due to high blood glucose level and oxidative stress. Here we aim to tackle this issue by means of a drug- and cell-free scaffolding approach. We found the nanoceria decorated on various types of scaffolds (fibrous or 3D-printed one; named nCe-scaffold) could render a therapeutic surface that can recapitulate the microenvironment: modulating oxidative stress while offering a nanotopological cue to regenerating cells. Mesenchymal stem cells (MSCs) recognized the nanoscale (tens of nm) topology of nCe-scaffolds, presenting highly upregulated curvature-sensing membrane protein, integrin set, and adhesion-related molecules. Osteogenic differentiation and mineralization were further significantly enhanced by the nCe-scaffolds. Of note, the stimulated osteogenic potential was identified to be through integrin-mediated TGF-β co-signaling activation. Such MSC-regulatory effects were proven in vivo by the accelerated bone formation in rat calvarium defect model. The nCe-scaffolds further exhibited profound enzymatic and catalytic potential, leading to effectively scavenging reactive oxygen species in vivo. When implanted in diabetic calvarium defect, nCe-scaffolds significantly enhanced early bone regeneration. We consider the currently-exploited nCe-scaffolds can be a promising drug- and cell-free therapeutic means to treat defective tissues like bone in diabetic conditions.

Dipeptidyl peptidase-4 inhibitors attenuates osteoporosis in patients with diabetes: A nationwide, retrospective, matched-cohort study in Taiwan

BACKGROUND

Patients with diabetes have a relatively high risk of fracture due to osteoporosis. However, the risk of osteoporosis associated with the use of oral hypoglycemic drugs and dipeptidyl peptidase-4 inhibitor (DPP-4i) by patients with diabetes is unclear. This study aimed to explore the effect of DPP-4i on the risk of osteoporosis in Taiwanese patients with type 2 diabetes mellitus (T2DM).

METHODS

This study enrolled 6339 patients on DPP-4i (DPP-4i group) and 25 356 patients without DPP-4i (non-DPP-4i group). They were matched by 1:4 propensity score matching, using confounding variables including sex, age, comorbidities, medication, and index year. Cox proportional hazards analysis was used to compare hospitalization and mortality during an average follow-up period of 7 years.

RESULTS

The mean age of patients in the two groups was 66 years. Men were slightly higher in number (51.79%) than women. At the end of the follow-up period, 113 (0.36%) patients had osteoporosis, of which 15 (0.24%) were in the case group and 98 (0.39%) in the control group. The risk of all-cause osteoporosis was significantly lower in the DPP-4i group than in the non-DPP-4i group (adjusted hazard ratio [HR] 0.616; 95% confidence interval [CI] 0.358-0.961; p = 0.011). Kaplan-Meier analysis showed that the preventive effect on osteoporosis was positively correlated with the cumulative dose of DPP-4i (log-rank, p = 0.039) with the class effect.

CONCLUSION

Compared with not using DPP-4i, the use of DPP-4i in Taiwanese T2DM patients was associated with a lower risk of osteoporosis due to the class effect, and the preventive effect was dose-dependent. However, larger prospective studies are needed to validate this finding and to explore the possible mechanism of the preventive effect of DPP-4i.

Angiogenic and Osteogenic Effects of Flavonoids in Bone Regeneration

Bone is a highly vascularised tissue that relies on a close spatial and temporal interaction between blood vessels and bone cells. As a result, angiogenesis is critical for bone formation and healing. The vascular system supports bone regeneration by delivering oxygen, nutrients, and growth factors, as well as facilitating efficient cell-cell contact. Most clinical applications of engineered bone grafts are hampered by insufficient vascularization after implantation. Over the last decade, a number of flavonoids have been reported to have osteogenic-angiogenic potential in bone regeneration because of their excellent bioactivity, low cost, availability, and minimal in vivo toxicity. During new bone formation, the osteoinductive nature of certain flavonoids is involved in regulating multiple signaling pathways contributing toward the osteogenic-angiogenic coupling. This review briefly outlines the osteogenic-angiogenic potential of those flavonoids and the mechanisms of their action in promoting bone regeneration. However, further studies are needed to investigate their delivery strategies and establish their clinical efficacy. This article is protected by copyright. All rights reserved.

How Do Drugs Affect the Skeleton? Implications for Forensic Anthropology

Simple Summary

Forensic anthropologists analyze human remains to assist in the identification of the deceased, predominantly by assessing age-at-death, sex, stature, ancestry and any unique identifying features. Whilst methods have been established to create this biological profile of the skeleton, these may be influenced by a number of factors. This paper, for the first time, provides an overview from a reading of the clinical and pharmacological literature to explore whether the intake of drugs can affect the skeleton and whether these may have implications for forensic anthropology casework. In effect, drugs such as tobacco, heroin, and prescription medications can alter bone mineral density, can increase the risk of fractures, destroy bone and changes to the dentition. By considering how drugs can affect the skeleton, forensic anthropologists can be aware of this when attempting to identify the deceased.

Abstract

Forensic anthropologists rely on a number of parameters when analyzing human skeletal remains to assist in the identification of the deceased, predominantly age-at-death, sex, stature, ancestry or population affinity, and any unique identifying features. During the examination of human remains, it is important to be aware that the skeletal features considered when applying anthropological methods may be influenced and modified by a number of factors, and particular to this article, prescription drugs (including medical and non-medical use) and other commonly used drugs. In view of this, this paper aims to review the medical, clinical and pharmacological literature to enable an assessment of those drug groups that as side effects have the potential to have an adverse effect on the skeleton, and explore whether or not they can influence the estimation of age-at-death, sex and other indicators of the biological profile. Moreover, it may be that the observation of certain alterations or inconsistencies in the skeleton may relate to the use of drugs or medication, and this in turn may help narrow down the list of missing persons to which a set of human remains could belong. The information gathered from the clinical and medical literature has been extracted with a forensic anthropological perspective and provides an awareness on how several drugs, such as opioids, cocaine, corticosteroids, non-steroidal anti-inflammatory drugs, alcohol, tobacco and others have notable effects on bone. Through different mechanisms, drugs can alter bone mineral density, causing osteopenia, osteoporosis, increase the risk of fractures, osteonecrosis, and oral changes. Not much has been written on the influence of drugs on the skeleton from the forensic anthropological practitioner perspective; and this review, in spite of its limitations and the requirement of further research, aims to investigate the current knowledge of the possible effects of both prescription and recreational drugs on bones, contributing to providing a better awareness in forensic anthropological practice and assisting in the identification process of the deceased.

Unmasking Fracture Risk in Type 2 Diabetes: The Association of Longitudinal Glycemic Hemoglobin Level and Medications

CONTEXT

Fracture risk is underestimated in people with type 2 diabetes (T2D).

OBJECTIVE

To investigate the longitudinal relationship of glycated hemoglobin (HbA1c) and common medications on fracture risk in people with T2D.

METHODS

This retrospective population-based cohort study was conducted using de-identified claims and electronic health record data obtained from the OptumLabs Data Warehouse for the period January 1, 2007, to September 30, 2015. For each individual, the study was conducted within a 2-year HbA1c observation period and a 2-year fracture follow-up period. A cohort of 157 439 individuals with T2D [age ≥ 55 years with mean HbA1c value ≥ 6%] were selected from 4 018 250 US Medicare Advantage/Commercial enrollees with a T2D diagnosis. All fractures and fragility fractures were measured.

RESULTS

With covariates adjusted, poor glycemic control in T2D individuals was associated with an 29% increase of all fracture risk, compared with T2D individuals who had adequate glycemic control (HR: 1.29; 95% CI, 1.22-1.36). Treatment with metformin (HR: 0.88; 95% CI, 0.85-0.92) and DPP4 inhibitors (HR: 0.93; 95% CI, 0.88-0.98) was associated with a reduced all fracture risk, while insulin (HR: 1.26; 95% CI, 1.21-1.32), thiazolidinediones (HR: 1.23; 95% CI, 1.18-1.29), and meglitinides (HR: 1.12; 95% CI, 1.00-1.26) were associated with an increased all fracture risk (All P value < 0.05). Bisphosphonates were associated similarly with increased fracture risk in the T2D and nondiabetic groups.

CONCLUSION

Longitudinal 2-year HbA1c is independently associated with elevated all fracture risk in T2D individuals during a 2-year follow-up period. Metformin and DPP4 inhibitors can be used for management of T2D fracture risk.

The Impact of GLP1 Agonists on Bone Metabolism: A Systematic Review

Background and Objectives: The association between diabetes mellitus and increased risk of bone fractures has led to the investigation of the impact of antidiabetic drugs on bone metabolism. Glucagon-like peptide-1 receptor agonists (GLP1RAs) are a relatively novel and promising class of anti-hyperglycemic drugs. In addition to their blood glucose lowering action, GLP1RAs seem to have additional pleiotropic properties such as a beneficial skeletal effect; although the underlying mechanisms are not completely understood. The present systematic review summarizes current evidence about GLP1RAs and their effects on bone metabolism and fracture. Methods: An extensive literature search was conducted based on electronic databases namely, PubMed, Google Scholar and Cochrane Central Register of Controlled Trials (CENTRAL) through October 2019 to January 2020 for articles related to bone mineral density, diabetes mellitus and GLP1RAs. We included articles published in English. Finally, we included four randomized controlled trials, three meta-analyses, a case-control study and a population-based cohort analysis. Results: Based on the articles included, the animal studies indicated the salutary skeletal effects of GLP1RAs in opposition to what has been commonly observed in human studies, showing that these agents have no impact on bone mineral density (BMD) and the turnover markers. Moreover, it was demonstrated that GLP1 was not associated with fracture risk as compared to other anti-hyperglycemic drugs. Conclusions: Findings from this systematic review have demonstrated the neutral impact of GLP1RAs on BMD. Moreover, further double-blind randomized controlled trials are needed to draw more meaningful and significant conclusions on the efficacy of GLP1RAs on BMD.

Cardiovascular benefits from SGLT2 inhibition in type 2 diabetes mellitus patients is not impaired with phosphate flux related to pharmacotherapy

The beneficial cardiorenal outcomes of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in patients with type 2 diabetes mellitus (T2DM) have been substantiated by multiple clinical trials, resulting in increased interest in the multifarious pathways by which their mechanisms act. The principal effect of SGLT2i (-flozin drugs) can be appreciated in their ability to block the SGLT2 protein within the kidneys, inhibiting glucose reabsorption, and causing an associated osmotic diuresis. This ameliorates plasma glucose elevations and the negative cardiorenal sequelae associated with the latter. These include aberrant mitochondrial metabolism and oxidative stress burden, endothelial cell dysfunction, pernicious neurohormonal activation, and the development of inimical hemodynamics. Positive outcomes within these domains have been validated with SGLT2i administration. However, by modulating the sodium-glucose cotransporter in the proximal tubule (PT), SGLT2i consequently promotes sodium-phosphate cotransporter activity with phosphate retention. Phosphatemia, even at physiologic levels, poses a risk in cardiovascular disease burden, more so in patients with type 2 diabetes mellitus (T2DM). There also exists an association between phosphatemia and renal impairment, the latter hampering cardiovascular function through an array of physiologic roles, such as fluid regulation, hormonal tone, and neuromodulation. Moreover, increased phosphate flux is associated with an associated increase in fibroblast growth factor 23 levels, also detrimental to homeostatic cardiometabolic function. A contemporary commentary concerning this notion unifying cardiovascular outcome trial data with the translational biology of phosphate is scant within the literature. Given the apparent beneficial outcomes associated with SGLT2i administration notwithstanding negative effects of phosphatemia, we discuss in this review the effects of phosphate on the cardiometabolic status in patients with T2DM and cardiorenal disease, as well as the mechanisms by which SGLT2i counteract or overcome them to achieve their net effects. Content drawn to develop this conversation begins with proceedings in the basic sciences and works towards clinical trial data.

Efficacy / safety balance of DPP-4 inhibitors versus SGLT2 inhibitors in elderly patients with type 2 diabetes

Dipeptidyl peptidase-4 inhibitors (DPP-4is) and sodium-glucose cotransporter type 2 inhibitors (SGLT2is) offer new options for the oral management of type 2 diabetes mellitus (T2DM), with the advantage in the elderly population to be devoid of a high risk of hypoglycaemia. SGLT2is have also shown benefits regarding cardiovascular (heart failure) and renal protection, including in patients with T2DM aged ≥ 65 years while DPP-4is have only proved cardiovascular and renal safety without superiority compared with placebo. The glucose-lowering efficacy of the two pharmacological classes is almost similar including in older patients with T2DM. However, the tolerance and safety profile may be highly different and overall more favourable with DPP-4is than with SGLT2is. Some adverse events have been reported with SGLT2is which may be more prevalent or severe in older patients than in younger patients. The present comprehensive review focuses on the benefit/risk balance in the elderly population with T2DM by comparing the profile of DPP-4is and SGLT2is regarding the following potential issues: metabolic disorders (hypoglycaemia and diabetic ketoacidosis); cardiac and vascular issues (atheromatous cardiovascular disease, heart failure, volume reduction hypotension, and lower limb amputations); renal endpoints including acute renal injury; risk of infections; digestive disorders; bone and skin adverse events; and cancer risk. Both DPP-4is and SGLT2is have their own advantages and disadvantages. Personalised treatment is recommended based upon the efficacy/safety profile of each drug class and individual patient characteristics that may be markedly different among the heterogeneous population of older individuals with T2DM.

Baicalin regulates mRNA expression of VEGF-c, Ang-1/Tie2, TGF-β and Smad2/3 to inhibit wound healing in streptozotocin-induced diabetic foot ulcer rats

Diabetic foot ulcer (DFU) is biggest life threats globally and increases their severity increases health complications for health of patients. The present study was investigated to recover the wound healing activity of baicalin in STZ-induced DFU rats by evaluating biochemical and molecular markers. The experimental animals induced with diabetes and excision wounds were treated with different doses of baicalin (25, 50, and 100 mg/kg). The serum glucose level, body weight and food intake were measured. In addition, DFU rat groups showed decreased food intake and increased body weight. The tissue was subjected to biochemical evaluation, histopathology, quantitative polymerase chain reaction and Western blot analysis. Histopathology reports revealed that diabetic wound control (DWC) + baicalin (100 mg/kg) treated group showed more than 90% recovery with more epithelization and remarkably improved angiogenesis and infiltration of the inflammatory cells. In this study we also proved that upregulated the p-ERK, ERK, HSP27, and p-HSP27 protein expression and mRNA expression of Ang-1, VEGF-c, TGF-β, Tie-2, and SMAD2/3 implicating the potential antidiabetic and wound healing property of baicalin. Thus, baicalin is a potential therapeutic candidate for a diabetic foot ulcer and chronic wounds treatment.

Vitexin, a fenugreek glycoside, ameliorated obesity-induced diabetic nephropathy via modulation of NF-κB/IkBα and AMPK/ACC pathways in mice

Obesity is one of the most critical risk factors for diabetes mellitus and plays a significant role in diabetic nephropathy (DN). The present investigation aimed to evaluate the possible mechanism of action of vitexin on obesity-induced DN in a high-fat diet (HFD)-fed experimental C57BL/6 mice model. Obesity was induced in male C57BL/6 mice by chronic administration of HFD, and mice were concomitantly treated with vitexin (15, 30, and 60 mg/kg, p.o.). HFD-induced increased renal oxido-nitrosative stress and proinflammatory cytokine levels were significantly inhibited by vitexin. The Western blot analysis suggested that alteration in renal NF-κB, IκBα, nephrin, AMPK, and ACC phosphorylation levels was effectively restored by vitexin treatment. Histological aberration induced in renal tissue after chronic administration of HFD was also reduced by vitexin. In conclusion, vitexin suppressed the progression of obesity-induced DN via modulation of NF-κB/IkBα and AMPK/ACC pathways in an experimental model of HFD-induced DN in C57BL/6J mice.

Spirulina supplementation improves bone structural strength and stiffness in streptozocin-induced diabetic rats

Spirulina (blue-green algae) contains a wide range of nutrients with medicinal properties which include β-carotene, chromium, and moderate amounts of vitamins B₁₂. This study aims to determine the preventive effect of spirulina against bone fragility linked to type 2 diabetes mellitus. Thirty Sprague-Dawley rats were divided into five groups (n = 6) and diabetes was induced using streptozocin. Rats with a plasma glucose level of 10 mmol/L and above were orally treated for twelve weeks with either a single dose of spirulina, metformin, or a combined dose of spirulina + metformin per day. After the treatment, blood and bones were taken for biochemical analysis, three-dimensional imaging, 3-point biomechanical analysis, histology imaging and gene expression using qPCR. Results showed that diabetes induction and treatment with metformin caused destruction in the trabecular microarchitecture of the femur bone, reduction in serum bone marker and expression of bone formation marker genes in the experimental rats. Spirulina supplementation showed improved trabecular microarchitecture with a denser trabecular network, increased 25-OH vitamin D levels, and lowered the level of phosphate and calcium in the serum. Biomechanical tests revealed increased maximum force, stress strain, young modulus and histology images showed improvement in regular mesh and an increase in osteoblasts and osteocytes. There was an increase in the expression of bone formation marker osteocalcin. The results suggest that spirulina supplementation was more effective at improving bone structural strength and stiffness in diabetic rats compared to metformin. Spirulina may be able to prevent T2DM-related brittle bone, lowering the risk of fracture.

Supplementation of Morin Restores the Altered Bone Histomorphometry in Hyperglycemic Rodents via Regulation of Insulin/IGF-1 Signaling

Pathological mechanisms underlining diabetic bone defects include oxidative damage and insulin/IGF-1 imbalance. Morin is a bioflavonoid with antioxidant and anti-diabetic effects. This study evaluates morin's protective effects against altered bone histomorphometry in diabetic rats through assessing insulin/IGF-1 pathway as a potential mechanism. Diabetic animals were administered two morin doses (15 and 30 mg/kg) for 5 weeks. Different serum hepatic and renal functions tests were assessed. Bone density and histomorphometry in cortical and trabecular tissues were evaluated histologically. The expressions of insulin, c-peptide and IGF-1 were estimated. In addition, the enzymatic activities of the major antioxidant enzymes were determined. Diabetic-associated alterations in serum glucose, aminotransferases, urea and creatinine were attenuated by morin. Diabetic bone cortical and trabecular histomorphometry were impaired with increased fibrosis, osteoclastic functions, osteoid formation and reduced mineralization, which was reversed by morin; particularly the 30 mg/kg dose. Insulin/IGF-1 levels were diminished in diabetic animals, while morin treatment enhanced their levels significantly. Diabetes also triggered systemic oxidative stress noticeably. The higher dose (30 mg/kg) of morin corrected the endogenous antioxidant enzymatic activities in diabetic rats. Findings indicate the potential value of morin supplementation against hyperglycemia-induced skeletal impairments. Activation of insulin/IGF-1 signaling could be the underlining mechanism behind these effects.

Hydroxycoumarin Scopoletin Inhibits Bone Loss through Enhancing Induction of Bone Turnover Markers in a Mouse Model of Type 2 Diabetes

Diabetes induces bone deterioration, which leads to increased risk of fracture, osteopenia, and osteoporosis. Thus, diabetes-associated bone fragility has been recognized as a diabetic complication. However, the pathophysiological effects of hyperglycemia on bone turnover remain unclear. Literature evidence demonstrates that anti-diabetic medications increase the risk of fractures in individuals with type 2 diabetes. Scopoletin is a naturally occurring hydroxycoumarin potentially exhibiting anti-inflammatory and antioxidant activities and ameliorating insulin resistance as an anti-diabetic agent. However, little is known regarding the effects of scopoletin on the impairment of bone remodeling that is caused by diabetes. The aim of this study was to identify that scopoletin was capable of inhibiting the impairment of bone remodeling and turnover in a mouse model of type 2 diabetes. Submicromolar scopoletin accelerated the formation TRAP-positive multinucleated osteoclasts (40.0 vs. 105.1%) and actin ring structures impaired by 33 mM glucose. Further, 1–20 μM scopoletin enhanced bone resorption and the induction of matrix-degrading enzymes in diabetic osteoclasts. The oral administration of 10 mg/kg scopoletin elevated serum RANKL/OPG ratio and osteocalcin level reduced in db/db mice along with an increase in BMD by ~6–14%; however, it was not effective in lowering blood glucose and hemoglobin glycation. In addition, the supplementation of scopoletin elevated the formation of trabecular bones and collagen fibers in femoral epiphysis and metaphysis with a thicker epiphyseal plate and cortical bones. Furthermore, 1–20 μM scopoletin enhanced ALP activity (4.39 vs. 7.02 nmol p-nitrophenyl phosphate/min/mg protein) and deposits of mineralized bone nodules in cultured osteoblasts reduced by 33 mM glucose. The treatment of diabetic osteoblasts with scopoletin stimulated the cellular induction of BMP-2 and osteopontin and Runx2 transcription. Accordingly, the administration of scopoletin protected mice from type 2 diabetes-associated bone loss through boosting bone remodeling via the robust induction of bone turnover markers of both osteoclasts and osteoblasts. These findings suggest that scopoletin could be a potential osteoprotective agent for the treatment of diabetes-associated bone loss and fractures.

Type 2 diabetes and bone fragility- An under-recognized association

BACKGROUND AND AIMS

Diabetes and osteoporosis are common chronic disorders with growing prevalence in the aging population. Skeletal fragility secondary to diabetes increases the risk of fractures and is underestimated by currently available diagnostic tools like fracture risk assessment (FRAX) and dual-energy X-ray absorptiometry (DXA). In this narrative review we describe the relationship and pathophysiology of skeletal fragility and fractures in Type 2 diabetes (T2DM), effect of glucose lowering medications on bone metabolism and the approach to diagnosing and managing osteoporosis and bone fragility in people with diabetes (PWD).

METHODS

A literature search was conducted on PubMed for articles in English that focused on T2DM and osteoporosis or bone/skeletal fragility. Articles considered to be of direct clinical relevance to physicians practicing diabetes were included.

RESULTS

T2DM is associated with skeletal fragility secondary to compromised bone remodeling and bone turnover. Long duration, poor glycemic control, presence of chronic complications, impaired muscle function, and anti-diabetic medications like thiazolidinediones (TZD) are risk factors for fractures among PWD. Conventional diagnostic tools like DXA and FRAX tool underestimate fracture risk in diabetes. Presence of diabetes does not alter response to anti-osteoporotic treatment in post-menopausal women.

CONCLUSION

Estimation of fragility fracture risk should be included in standard of care for T2DM along with screening for traditional complications. Physicians should proactively screen for and manage osteoporosis in people with diabetes. It is important to consider effects on bone health when selecting glucose lowering agents in people at risk for fragility fractures.

Effects of ipragliflozin versus metformin in combination with sitagliptin on bone and muscle in Japanese patients with type 2 diabetes mellitus: Subanalysis of a prospective, randomized, controlled study (PRIME-V study)

AIMS/INTRODUCTION

Recent randomized clinical trials have suggested that sodium-glucose cotransporter 2 inhibitors might reduce cardiovascular events and heart failure, and have renal protective effects. Despite these remarkable benefits, the effects of sodium-glucose cotransporter 2 inhibitors on bone and muscle are unclear.

MATERIALS AND METHODS

A subanalysis of a randomized controlled study was carried out to evaluate the effects of the sodium-glucose cotransporter 2 inhibitor, ipragliflozin, versus metformin on bone and muscle in Japanese patients with type 2 diabetes mellitus (baseline body mass index ≥22 kg/m2 and hemoglobin A1c 7-10%) who were already receiving sitagliptin. These patients were randomly administered ipragliflozin 50 mg or metformin 1,000-1,500 mg daily. The effects of these medications on the bone formation marker, bone alkali phosphatase; the bone resorption marker, tartrate-resistant acid phosphatase 5b (TRACP-5b); handgrip strength; abdominal cross-sectional muscle area; and bone density of the fourth lumbar vertebra were evaluated.

RESULTS

After 24 weeks of treatment, the changes in bone density of the fourth lumbar vertebra, handgrip strength and abdominal cross-sectional muscle area were not significantly different between the two groups. However, TRACP-5b levels increased in patients treated with ipragliflozin compared with patients treated with metformin (median 11.94 vs -10.30%, P < 0.0001), showing that ipragliflozin can promote bone resorption.

CONCLUSIONS

There were no adverse effects on bone or muscle when sitagliptin was used in combination with either ipragliflozin or metformin. However, ipragliflozin combination increased the levels of TRACP-5b. A long-term study is required to further understand the effects of this TRACP-5b increase caused by ipragliflozin.

Correlation of Osteoporosis in Patients With Newly Diagnosed Type 2 Diabetes: A Retrospective Study in Chinese Population

This study aimed to explore the risk factors attributed to osteoporosis in newly type 2 diabetes mellitus (T2DM) patients. This study aimed to recruit 244 T2DM patients and 218 non-diabetic controls. We collected demographic characteristics, medical history, bone mineral density and biomarkers including bone specific alkaline phosphatase (BALP), osteocalcin, N-terminal peptide of type I procollagen (P1NP), tartrate-resistant acid phosphatase 5b (TRCAP-5b), β-Cross Laps of type I collagen-containing cross-linked C-telopeptide (β-CTX), 25-hydroxyvitamin D, parathyroid hormone were recorded or detected. Bone mineral density (BMD) was our primary outcome. Based on the result of BMD, we divided both the control group and T2DM group into three subgroups: normal bone mass, osteopenia and osteoporosis. In control group, we found age, sex, menopausal status, BMI, P1NP, BALP, TRACP-5b, osteocalcin, and corrected serum calcium are differential among three subgroups. In T2DM group, we found age, sex, menopausal status, drinking status, BMI, HbA1c, TRACP-5b and OC were differential among three subgroups. In T2DM and control groups, age, female, postmenopausal status, BALP, TRACP-5b and osteocalcin were positively correlated while BMI was negatively correlated with osteoporosis. In control group, β-CTX was positively correlated with osteoporosis. In T2DM group, HbA1c and corrected serum calcium concentration were positively correlated with osteoporosis. After further adjustment of age, BMI in male, TRACP-5b was positively correlated with the risk of osteoporosis in newly diagnosed T2DM. After adjusted of age, BMI and menopausal status in female, OC was positively correlated with the risk of osteoporosis in newly diagnosed T2DM and controls. In female T2DM, BALP and P1NP were positively correlated with the risk of osteoporosis. In conclusion, age, BMI and menopausal status are common risk factors for osteoporosis in diabetic and non-diabetic patients, however TRACP-5b, BALP and osteocalcin are special risk factors for osteoporosis in newly diagnosed T2DM patients but not non-diabetic patients, which may be applied to identify osteoporosis risk in T2DM patients, but this result needs to be proven with fracture data.

Effects of Anti-Diabetic Drugs on Fracture Risk: A Systematic Review and Network Meta-Analysis

PURPOSE

Available data on the effects of anti-diabetic drugs on fracture risk are contradictory. Therefore, our study aimed to analyze all available data on the effects of anti-diabetic drugs on fracture risk in type 2 diabetes mellitus (T2DM) patients.

METHODS

Embase, Medline, ClinicalTrials.gov, and Cochrane CENTRAL were searched for relevant trials. All data analyses were performed with STATA (12.0) and R language (3.6.0). Risk ratio (RR) with its 95% confidence interval (CI) was calculated by combining data for the fracture effects of anti-diabetic drugs, including sodium-glucose co-transporter 2 (SGLT2) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, meglitinides, α-glucosidase inhibitors, thiazolidinediones, biguanides, insulin, and sulfonylureas.

RESULTS

One hundred seventeen eligible randomized controlled trials (RCTs) with 221,364 participants were included in this study. Compared with placebo, trelagliptin (RR 3.51; 1.58-13.70) increased the risk of fracture, whereas albiglutide (RR 0.29; 0.04-0.93) and voglibose (RR 0.03; 0-0.11) decreased the risk of fracture. Other medications were comparable in terms of their effects on fracture risk, and no statistical significance was observed. In terms of fractures, voglibose (0.01%) may be the safest option, and trelagliptin (13.64%) may be the worst. Sensitivity analysis results were consistent with those of the main analysis. No statistically significant differences were observed in the regression coefficients of age (1.03; 0.32-2.1), follow-up duration (0.79; 0.27-1.64), and sex distribution (0.63; 0.15-1.56).

CONCLUSIONS

We found varied results on the association between the use of anti-diabetic drugs and fracture risk. Specifically, trelagliptin raised the risk of fracture, whereas voglibose and albiglutide showed benefit with statistical difference. Other drugs were comparable in terms of their effects on fracture risk. Some drugs (omarigliptin, sitagliptin, vildagliptin, saxagliptin, empagliflozin, ertugliflozin, rosiglitazone, pioglitazone, and nateglinide) may increase the risk of fracture, while others (such as dulaglutide, exenatide, liraglutide, semaglutide, lixisenatide, linagliptin, alogliptin, canagliflozin, dapagliflozin, glipizide, gliclazide, glibenclamide, glimepiride, metformin, and insulin) may show benefits. The risk of fracture was independent of age, sex distribution, and the duration of exposure to anti-diabetic drugs. When developing individualized treatment strategies, the clinical efficacy of anti-diabetic drugs must be weighed against their benefits and risks brought about by individual differences of patients.

SYSTEMATIC REVIEW REGISTRATION

This Systematic Review was prospectively registered on the PROSPERO (https://www.crd.york.ac.uk/PROSPERO/, registration number CRD42020189464).

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

Use of in vitro bone models to screen for altered bone metabolism, osteopathies, and fracture healing: challenges of complex models

Approx. every third hospitalized patient in Europe suffers from musculoskeletal injuries or diseases. Up to 20% of these patients need costly surgical revisions after delayed or impaired fracture healing. Reasons for this are the severity of the trauma, individual factors, e.g, the patients’ age, individual lifestyle, chronic diseases, medication, and, over 70 diseases that negatively affect the bone quality. To investigate the various disease constellations and/or develop new treatment strategies, many in vivo, ex vivo, and in vitro models can be applied. Analyzing these various models more closely, it is obvious that many of them have limits and/or restrictions. Undoubtedly, in vivo models most completely represent the biological situation. Besides possible species-specific differences, ethical concerns may question the use of in vivo models especially for large screening approaches. Challenging whether ex vivo or in vitro bone models can be used as an adequate replacement for such screenings, we here summarize the advantages and challenges of frequently used ex vivo and in vitro bone models to study disturbed bone metabolism and fracture healing. Using own examples, we discuss the common challenge of cell-specific normalization of data obtained from more complex in vitro models as one example of the analytical limits which lower the full potential of these complex model systems.

Peroxisome proliferator activated receptor γ promotes mineralization and differentiation in cementoblasts via inhibiting Wnt/β-catenin signaling pathway

Peroxisome proliferator activated receptor γ (PPARγ) is a member of the nuclear receptor family of transcription factors, which involved in inflammation regulating and bone remodeling. Rare studies explored the effects of PPARγ on mineralization and differentiation in cementoblasts. To explore the potential approaches to repair the damaged periodontal tissues especially for cementum, the present study aims to investigate the effects and the regulating mechanism of PPARγ on mineralization and differentiation in cementoblasts. Murine cementoblast cell lines (OCCM-30) were cultured in basic medium for 24 hours/48 hours or in mineralization medium for 3/7/10 days, respectively at addition of dimethyl sulphoxide, rosiglitazone (PPARγ agonist), GW9662 (PPARγ antagonist), lithium chloride (LiCl), tumor necrosis factor-α (TNF-α), or respective combination. Expression of mineralization genes alkaline phosphatase (ALP), runt related transcription factors 2 (RUNX2), and osteocalcin (OCN) were detected by quantitative real-time polymerase chain reaction or/and Western blot. ALP staining and alizarin red staining were used to evaluate the mineralization in OCCM-30 cells. The change of β-catenin expression and translocation in cytoplasm/nucleus was analyzed by Western blot and immunofluorescence. The results showed that PPARγ agonist rosiglitazone improved the expression of ALP, RUNX2, and OCN, deepened ALP staining, increased mineralized nodules formation, and decreased β-catenin expression in the nucleus. LiCl, an activator of the Wnt signaling pathway, inhibited the expression of mineralization genes and reversed the upregulated expression of mineralization genes resulted from rosiglitazone. Under inflammatory microenvironment, rosiglitazone not only suppressed the expression of interleukin-1β caused by TNF-α, but improved the expression of mineralization genes in OCCM-30 cells. In conclusion, PPARγ could promote mineralization and differentiation in cementoblasts via inhibiting the Wnt/β-catenin signaling pathway, which would shed new light on the treatment of periodontitis and periodontal tissue regeneration.

Chondroitin Sulfate Prevents STZ Induced Diabetic Osteoporosis through Decreasing Blood Glucose, AntiOxidative Stress, Anti-Inflammation and OPG/RANKL Expression Regulation

Chondroitin sulfate (CS) has antioxidative, anti-inflammatory, anti-osteoarthritic and hypoglycemic effects. However, whether it has antidiabetic osteoporosis effects has not been reported. Therefore, in this study, we established a STZ-induced diabetic rat model; CS (500 mg kg⁻¹ d⁻¹) was orally administrated for eight weeks to study its preventive effects on diabetic osteoporosis. The results showed that eight weeks of CS treatment improved the symptoms of diabetes; the CS-treated group has increased body weight, decreased water or food intake, decreased blood glucose, increased bone-mineral density, repaired bone morphology and decreased femoral osteoclasts and tibia adipocytes numbers. After CS treatment, bone histomorphometric parameters returned to normal, the levels of serum inflammatory cytokines (IL-1β, IL-6 and TNF-α) decreased significantly, serum SOD, GPX and CAT activities increased and MDA level increased. In the CS-treated group, the levels of serum ALP, CTX-1, TRACP 5b, osteocalcin and RANKL decreased and the serum RUNX 2 and OPG levels increased. Bone immunohistochemistry results showed that CS can effectively increase the expression of OPG and RUNX2 and reduce the expression of RANKL in diabetic rats. All of these indicate that CS could prevent STZ induced diabetic osteoporosis—mainly through decreasing blood glucose, antioxidative stress, anti-inflammation and regulation of OPG/RANKL expression. CS can therefore effectively prevent bone loss caused by diabetes.

DPP4 Activities Are Associated with Osteopenia/Osteoporosis and Fracture Risk in Newly Diagnosed Type 2 Diabetes

BACKGROUND

Recent studies have shown the beneficial effect of dipeptidyl peptidase-4 (DPP4) inhibitor on bone turnover in diabetes mellitus. However, little clinical evidence for DPP4 activity in newly diagnosed type 2 diabetes is available. This study was designed to investigate the relationship between plasma DPP4 activity and osteoporosis/osteopenia and fracture risk in newly diagnosed type 2 diabetes.

METHODS

A total of 147 subjects with newly diagnosed type 2 diabetes were enrolled for this cross-sectional study. The bone mineral density (BMD) at the lumbar spine (L1-4) and femoral neck (FN) was measured by dual-energy X-ray absorptiometry (DXA). The 10-year probability of major osteoporotic fracture (MOF) and hip fracture (HF) was assessed by a modified fracture risk algorithm (FRAX) tool. The plasma DPP4 activity and clinical variables were measured. Correlation analyses between DPP4 activity and osteoporosis/osteopenia and fracture risk were performed.

RESULTS

Elevated plasma DPP activities were significantly associated with a higher proportion of osteoporosis/osteopenia (50% for quartile-1, 56.4% for quartile-2, 65.8% for quartile-3 and 72.2% for quartile-4). With increasing plasma DPP activities, the incidence rate of osteoporosis/osteopenia is gradually increasing (P for the trend between quartiles = 0.04). Of note, a statistically significant linear correlation was found between plasma DPP4 activities and modified FRAX MOF (r = 0.20, P=0.02). Moreover, plasma DPP4 activities were also positively related to modified FRAX HF in newly diagnosed type 2 diabetic patients (r = 0.21, P=0.01).

CONCLUSIONS

Elevated plasma DPP4 activity tended to be associated with a higher proportion of osteoporosis/osteopenia and increased the fracture risk in newly diagnosed type 2 diabetes.

Relationship Between Metabolic Syndrome and Bone Health - An Evaluation of Epidemiological Studies and Mechanisms Involved

Metabolic syndrome (MetS) and osteoporosis are two medical problems plaguing the ageing populations worldwide. Though seemingly distinctive to each other, metabolic derangements are shown to influence bone health. This review summarises the relationship between MetS and bone health derived from epidemiological studies and explains the mechanistic basis of this relationship. The discourse focuses on the link between MetS and bone mineral density, quantitative sonometric indices, geometry and fracture risk in humans. The interesting sex-specific trend in the relationship, probably due to factors related to body composition and hormonal status, is discussed. Mechanistically, each component of MetS affects the bone distinctly, forming a complex interacting network influencing the skeleton. Lastly, the effects of MetS management, such as pharmacotherapies, exercise and bariatric surgery, on bone, are presented. This review aims to highlight the significant relationship between MetS and bone, and proper management of MetS with the skeletal system in mind could prevent cardiovascular and bone complications.

Mineral and Electrolyte Disorders With SGLT2i Therapy

The newly developed sodium‐glucose cotransporter 2 inhibitors (SGLT2is) effectively modulate glucose metabolism in diabetes. Although clinical data suggest that SGLT2is (empagliflozin, dapagliflozin, ertugliflozin, canagliflozin, ipragliflozin) are safe and protect against renal and cardiovascular events, very little attention has been dedicated to the effects of these compounds on different electrolytes. As with other antidiabetic compounds, some effects on water and electrolytes balance have been documented. Although the natriuretic effect and osmotic diuresis are expected with SGLT2is, these compounds may also modulate urinary potassium, magnesium, phosphate, and calcium excretion. Notably, they have had no effect on plasma sodium levels and promoted only small increases in serum potassium and magnesium concentrations in clinical trials. Moreover, SGLT2is may induce an increase in serum phosphate, FGF‐23, and PTH; reduce 1,25‐dihydroxyvitamin D; and generate normal serum calcium. Some published and preliminary reports, as well as unconfirmed reports have suggested an association with bone fractures. Some homeostasis perturbations are transient, whereas others may persist, suggesting that the administration of SGLT2is may affect electrolyte balances in exposed subjects. Although current evidence supports their safety, additional efforts are needed to elucidate the long‐term impact of these compounds on chronic kidney disease, mineral metabolism, and bone health. Indeed, the limited follow‐up studies and the heterogeneity of the case‐mix of different randomized controlled trials preclude a definitive answer on the impact of these compounds on long‐term outcomes such as the risk of bone fracture. Here we review the current understanding of the mechanisms involved in electrolyte handling and the available data on the clinical implications of electrolytes and mineral metabolism perturbations induced by SGLT2i administration. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Bone mineral density in patients with longstanding type 1 diabetes: Results from the Canadian Study of Longevity in Type 1 Diabetes

AIM

It is currently unclear if longstanding type 1 diabetes (T1D) affects bone mineral density (BMD).

METHODS

BMD measured by dual-energy X-ray absorptiometry and history of fragility fracture was determined in 75 T1D participants with ≥50 years of diabetes duration and 75 age- and sex-matched non-diabetic controls. BMD T-scores were determined for the lumbar spine (LS), total hip (TH) and femoral neck (FN).

RESULTS

T1D participants had median diabetes duration of 54 [52, 58] years, 41 (55%) were females, and mean A_1c was 7.3 ± 0.8%. T1D females had higher LS T-scores compared to female controls (-0.3 ± 1.2 vs. -1.1 ± 1.4, p = 0.014), lower FN T-scores (-1.5 ± 1.0 vs. -1.2 ± 0.9, p = 0.042) and more fragility fractures (7 (17%) vs. 1 (2%), p = 0.021). In T1D, higher A1c was associated with higher adjusted odds of fragility fracture (p = 0.006). T1D males and controls showed no difference in BMD or fractures.

CONCLUSIONS

There were no substantial differences in T-score between T1D and matched controls; however, T1D females showed higher BMD at the LS and possibly paradoxically higher fragility fractures compared to matched controls. These findings suggest that lower T-scores may not be associated with a history of fragility fracture in females with longstanding T1D and that other factors should be investigated.

The use of metformin, insulin, sulphonylureas, and thiazolidinediones and the risk of fracture: Systematic review and meta-analysis of observational studies

Certain glucose-lowering medications have been implicated in the risk of fracture. While there is convincing evidence from randomized controlled trials (RCTs) that thiazolidinedione use is associated with a higher risk of fracture, the effects of metformin, insulin, and sulphonylureas on the risk of fracture remain equivocal because these medications are not generally investigated in RCTs. A meta-analysis of observational studies to provide further insights into the association between the use of metformin, insulin, sulphonylureas, or thiazolidinediones and the risk of fracture was performed. PubMed and Web of Science databases were searched to identify relevant observational studies. A random effects model was used to estimate the summary relative risks (RRs) with 95% confidence intervals (CIs). The use of insulin (RR 1.49, 95% CI 1.29, 1.73; n = 23 studies), sulphonylureas (RR 1.30, 95% CI 1.18, 1.43; n = 10), and thiazolidinediones (RR 1.24, 95% CI 1.13, 1.35; n = 14) was associated with an increased risk of fracture, whereas the use of metformin was associated with a reduced risk of fracture (RR 0.86, 95% CI 0.75, 0.99; n = 12). Regarding types of thiazolidinediones, both pioglitazone (RR 1.38, 95% CI 1.23, 1.54; n = 5) and rosiglitazone (RR 1.34, 95% CI 1.14, 1.58; n = 5) were positively associated with the risk of fracture. In summary, there is compelling evidence to discourage the use of thiazolidinediones in individuals with an increased risk of fracture, whereas metformin appears to have a good safety profile for the risk of fracture. The reduced risk of fracture with metformin could possibly be due to the reduced overall risk of fracture among metformin users, as this medication is typically prescribed in the early stages of type 2 diabetes mellitus. The use of insulin or sulphonylureas may increase fracture risk; this risk is most likely attributed to an increased risk of hypoglycaemia-induced falls. Further confirmation by additional RCTs is required to determine whether the observed association between the use of metformin, insulin, or sulphonylureas and the risk of fracture is due to treatment with these medications or confounding factors.

Risk of Fractures Associated with Dipeptidyl Peptidase-4 Inhibitor Treatment: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

More and more studies suggest that type 2 diabetes mellitus (T2DM) can lead to an increased fracture risk. Some previous clinical studies and experimental data have shown that some antidiabetic drugs can increase or decrease the incidence of fractures.

METHODS

We searched Medline, Embase, Cochrane Library, and the ClinicalTrials.gov website ( https://www.clinicaltrials.gov ) for published or unpublished randomized controlled trials (RCTs) from inception through 2 December 2018 to compare the effects of dipeptidyl peptidase-4 (DDP-4) inhibitors with active control drugs or placebo in T2DM patients. All RCTs had a duration of at least 12 weeks, and the ultimate measure was whether a fracture occurs or not. We calculated odds ratios and their 95% confidence intervals by the fixed effect Mantel-Haenszel model. Publication bias was investigated firstly through visual observation of funnel plot asymmetry and then through Begg's test or Egger's test. The Cochrane bias risk tools were used to assess the quality of included studies.

RESULTS

Eighty-seven eligible RCTs were included in this study. Of 93,772 participants, 49,270 patients received therapy and 44,502 were control patients. Five kinds of DDP-4 inhibitors were included: sitagliptin, saxagliptin, alogliptin, linagliptin and vildagliptin. There were 676 fractures in the DDP-4 inhibitor treatment group and 646 in the control group. The median average glycosylated hemoglobin level was 8.2%. DDP-4 inhibitor treatment did not seem to influence the fracture risk, no matter whether compared with placebo or active comparators in T2DM patients (Mantel-Haenszel odds ratio (MH-OR) = 1.01, 95% CI 0.90-1.12, P = 0.92). After three subgroup analyses which were defined by drug type, control regimen and duration, the results were still stable.

CONCLUSION

This systematic review and meta-analysis shows that DDP-4 inhibitors do not affect the fracture risk when compared with antidiabetic drugs or placebo in T2DM patients.

Risk of fracture with dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists, or sodium-glucose cotransporter-2 inhibitors in real-world use: systematic review and meta-analysis of observational studies

In the present meta-analysis based on real-world data, the use of dipeptidyl peptidase-4 inhibitors (DPP-4i), glucagon-like peptide-1 receptor agonists (GLP-1ra), or sodium-glucose cotransporter-2 inhibitors (SGLT2i) was not associated with the risk of fracture.

INTRODUCTION

Cumulative evidence from randomized control trials (RCTs) with limited fracture events showed that the use of DPP-4i, GLP-1ra, or SGLT2i may not affect the risk of fracture. However, additional insights from large population-based studies with routinely collected data on fracture events and an adequate amount of fracture events are necessary to draw firm conclusions. To refine and complement the results from RCTs, a systematic review and meta-analysis of observational studies were performed to investigate the association between the use of DPP-4i, GLP-1ra, or SGLT2i and the risk of fracture in real-world settings.

METHODS

The PubMed and Web of Science databases were searched to identify relevant observational studies. A random-effect model was used to estimate the summary relative risks (RRs).

RESULTS

The use of DPP-4i (RR 0.83, 95% CI [confidence interval] 0.60, 1.14; n = 11), GLP-1ra (RR 0.65, 95% CI 0.24, 1.74; n = 4), or SGLT2i (RR 1.02, 95% CI 0.91, 1.16; n = 4) was not associated with the risk of fracture. In general, there was a consistent lack of association between the use of DPP-4i or GLP-1ra and the risk of fracture across nearly all subgroups, except for a significantly reduced risk of hip fracture with the use of GLP-1ra (RR 0.21, 95% CI 0.04, 0.98).

CONCLUSIONS

Cumulative real-world evidence does not support an association between the use of DPP-4i, GLP-1ra, or SGLT2i and the risk of fracture. Our findings, together with the cumulative evidence from RCTs, should reassure policy makers and medical practitioners that the use of these medications is unlikely to increase the risk of fracture among type 2 diabetes mellitus patients in general. Further studies need to investigate the long-term impact of these drugs on the fracture risk, particularly in high-risk populations.

Lean Women on Metformin and Oral Contraceptives for Polycystic Ovary Syndrome Demonstrate a Dehydrated Osteosarcopenic Phenotype: A Pilot Study

Scarce data exist on the body composition of lean women with polycystic ovary syndrome (PCOS) on treatment with metformin and oral contraceptives (OCs). Thirty-four lean (body mass index 18.5–24.9 kg/m²) women (17 with PCOS on metformin and OCs treatment for six months and 17 controls) aged 18–40 years were assessed for body composition parameters (fat, muscle, glycogen, protein masses, bone masses, and body water compartments) and phase angles. PCOS patients demonstrated lower muscle, glycogen and protein masses (U = 60, p = 0.003), along with a lower bone mineral content and mass (U = 78, p = 0.021; U = 74, p = 0.014) than their healthy counterparts, while total and abdominal fat masses were similar between the two groups. PCOS patients also exhibited increased extracellular body water (U = 10, p < 0.001) and decreased intracellular water, compatible with low-grade inflammation and cellular dehydration. Key differences in body composition between women with PCOS and controls demonstrated an osteosarcopenic body composition phenotype in PCOS patients. A confirmation of these findings in larger studies may render osteosarcopenia management a targeted adjunct therapy in women with PCOS.

Effects of GLP-1 receptor analogue liraglutide and DPP-4 inhibitor vildagliptin on the bone metabolism in ApoE-/- mice

Background

It has been reported that glucagon-like peptide-1 (GLP-1) can alleviate diabetic osteoporosis (DOP). This study was to investigate the effects of GLP-1RA liraglutide and dipeptidyl peptdase-4 (DPP-4) inhibitor vildagliptin on the advanced glycation end products (AGEs)-induced bone injury in ApoE^-/- mice with euglycemia.

Methods

The bone markers OC, PINP, PTH, TRACP and CTX, the mRNA and protein expressions of RAGE in the femur, and the femoral morphology index were determined to evaluate whether the osteoporosis was improved by liraglutide or vildagliptin.

Results

AGEs adversely affected the bone metabolism, characterized by reduced OC and increased CTX. However, vildagliptin reduced AGEs and increased OC, and liraglutide significantly decreased AGEs and PTH. Both vildagliptin and liraglutide had no effects on the bone metrology and RAGE expression in the femurs of ApoE^-/- mice.

Conclusions

The elevated AGEs may exacerbate osteogenesis and increase bone resorption, and vildagliptin/liraglutide may improve bone metabolism.

The anti-diabetic activities, gut microbiota composition, the anti-inflammatory effects of Scutellaria-coptis herb couple against insulin resistance-model of diabetes involving the toll-like receptor 4 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellaria-coptis herb couple (SC) is one of the well-known herb couples in many traditional Chinese compound formulas used for the treatment of diabetes mellitus (DM), which has been used to treat DM for thousands of years in China.

AIM OF THE STUDY

Few studies have confirmed in detail the anti-diabetic activities of SC in vivo and in vitro. The present investigations aimed to evaluate the anti-diabetic activity of SC in type 2 diabetic KK-Ay mice and in RAW264.7 macrophages to understand its possible mechanism.

MATERIALS AND METHODS

High-performance liquid chromatography with ultraviolet detection (HPLC-UV) and LC-LTQ-Orbitrap Pro mass spectrometry were used to analyze the active ingredients of SC extracts and control the quality. A type 2 diabetic KK-Ay mice model was established by high-fat diet. Body weight, fasting blood glucose levels, fasting blood insulin levels, glycosylated hemoglobin and glycosylated serum protein were measured. The effects of SC on total cholesterol (TC), high-density lipoprotein (HDL) and triglyceride (TG) levels were examined. The lipopolysaccharide (LPS), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-α) levels were measured. Gut microbial communities were assayed by polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis (PCR-DGGE) methods. The expressions of Toll-like receptor 4 (TLR4) and MyD88 protein in the colons were measured by western blot. In RAW264.7 macrophages, IL-6, TNF-α, TLR4 and MyD88 protein levels were measured by enzyme-linked immunosorbent assay (ELISA) kits or western blot, and the mRNA expression of IL-6, TNF-α and TLR4 was examined by the real time PCR.

RESULTS

The present results showed that the SC significantly increased blood HDL and significantly reduced fasting blood glucose, fasting blood insulin, glycosylated hemoglobin, glycosylated serum protein, TC, TG, LPS, IL-6 and TNF-α levels (P < 0.05 or P < 0.01) in type-2 diabetic KK-Ay mice. Furthermore, SC could regulate the structure of intestinal flora. Additionally, the expressions of TLR4 and MyD88 protein in the colons were significantly decreased in the model group (P < 0.05 or P < 0.01). However, SC had no significant effect on weight gain. In RAW264.7 macrophages, SC containing serum (SC-CS) (5%, 10% and 20%) significantly decreased IL-6, TNF-α, TLR4 and MyD88 protein levels and the mRNA expression of IL-6, TNF-α and TLR4 (P < 0.05 or P < 0.01).

CONCLUSIONS

The anti-diabetic effects of SC were attributed to its regulation of intestinal flora and anti-inflammation involving the TLR4 signaling pathway. These findings provide a new insight into the anti-diabetic application for SC in clinical settings and display the potential of SC in the treatment of DM.

An update on therapies for the treatment of diabetes-induced osteoporosis

Introduction: Currently, 424 million people aged between 20 and 79 years worldwide are diabetic. More than 25% of adults aged over 65 years in North America have Type 2 diabetes mellitus (DM). Diabetes-induced osteoporosis (DM-OS) is caused by chronic hyperglycemia, advanced glycated end products and oxidative stress. The increase in the prevalence of DM-OS has prompted researchers to develop new biological therapies for the management of DM-OS. Areas covered: This review covered the current and novel biological agents used in the management of DM-OS. Data were retrieved from PubMed, Scopus, American Diabetes Association and International Osteoporosis Foundation websites, and ClinicalTrials.gov. The keywords for the search included: DM, osteoporosis, and management. Expert opinion: Several biological molecules have been examined in order to find efficient drugs for the treatment of DM-OS. These biological agents include anti-osteoporosis drugs: net anabolics (parathyroid hormone/analogs, androgens, calcilytics, anti-sclerostin antibody), net anti-resorptive osteoporosis drugs (calcitonin, estrogen, selective estrogen receptor modulators, bisphosphonates, RANKL antibody) and anti-diabetic drugs (alpha glucosidase inhibitors, sulfonylureas, biguanides, meglitinides, thiazolidinediones, GLP-1 receptor agonists, dipeptidylpeptidase-4 inhibitors, sodium glucose co-transporter-2 inhibitors, insulin). Biological medications that effectively decrease hyperglycemia and, at the same time, maintain bone health would be an ideal drug/drug combination for the treatment of DM-OS.

Long-term efficacy and safety of ertugliflozin in patients with type 2 diabetes mellitus inadequately controlled with metformin monotherapy: 104-week VERTIS MET trial

AIM

To evaluate the long-term efficacy and safety of ertugliflozin in adults with type 2 diabetes mellitus inadequately controlled on metformin.

MATERIALS AND METHODS

A 104-week Phase III, randomized double-blind study with a 26-week placebo-controlled period (Phase A) and a 78-week period (Phase B) where blinded glimepiride was added to non-rescued placebo participants with fasting fingerstick glucose ≥6.1 mmol/L. Results through week 104 are reported.

RESULTS

Mean (standard error) change in HbA1c from baseline was -0.7% (0.07) and -1.0% (0.07) at week 52; -0.6% (0.08) and -0.9% (0.08) at week 104 for ertugliflozin 5 and 15 mg. At week 52, 34.8% and 36.6% participants had HbA1c <7.0%, and 24.6% and 33.7% at week 104, for ertugliflozin 5 and 15 mg. Ertugliflozin reduced fasting plasma glucose (FPG), body weight and systolic blood pressure (SBP) from baseline through week 104. The incidence of female genital mycotic infections (GMIs) was higher with ertugliflozin, and symptomatic hypoglycaemia was lower for ertugliflozin versus placebo/glimepiride. Minimal bone mineral density (BMD) changes were observed, similar to placebo/glimepiride, except at total hip where reduction in BMD was greater with ertugliflozin 15 mg versus placebo/glimepiride: difference in least squares means (95% CI) -0.50% (-0.95, -0.04) at week 52 and -0.84% (-1.44, -0.24) at week 104.

CONCLUSIONS

Ertugliflozin maintained improvements from baseline in HbA1c, FPG, body weight and SBP through week 104. Ertugliflozin was well tolerated, with non-clinically relevant changes in BMD. Compared with placebo/glimepiride, ertugliflozin increased female GMIs, but reduced the incidence of symptomatic hypoglycaemia. ClinicalTrials.gov Identifier: NCT02033889.

Diabetes pharmacotherapy and effects on the musculoskeletal system

Persons with type 1 or type 2 diabetes have a significantly higher fracture risk than age-matched persons without diabetes, attributed to disease-specific deficits in the microarchitecture and material properties of bone tissue. Therefore, independent effects of diabetes drugs on skeletal integrity are vitally important. Studies of incretin-based therapies have shown divergent effects of different agents on fracture risk, including detrimental, beneficial, and neutral effects. The sulfonylurea class of drugs, owing to its hypoglycemic potential, is thought to amplify the risk of fall-related fractures, particularly in the elderly. Other agents such as the biguanides may, in fact, be osteo-anabolic. In contrast, despite similarly expected anabolic properties of insulin, data suggests that insulin pharmacotherapy itself, particularly in type 2 diabetes, may be a risk factor for fracture, negatively associated with determinants of bone quality and bone strength. Finally, sodium-dependent glucose co-transporter 2 inhibitors have been associated with an increased risk of atypical fractures in select populations, and possibly with an increase in lower extremity amputation with specific SGLT2I drugs. The role of skeletal muscle, as a potential mediator and determinant of bone quality, is also a relevant area of exploration. Currently, data regarding the impact of glucose lowering medications on diabetes-related muscle atrophy is more limited, although preclinical studies suggest that various hypoglycemic agents may have either aggravating (sulfonylureas, glinides) or repairing (thiazolidinediones, biguanides, incretins) effects on skeletal muscle atrophy, thereby influencing bone quality. Hence, the therapeutic efficacy of each hypoglycemic agent must also be evaluated in light of its impact, alone or in combination, on musculoskeletal health, when determining an individualized treatment approach. Moreover, the effect of newer medications (potentially seeking expanded clinical indication into the pediatric age range) on the growing skeleton is largely unknown. Herein, we review the available literature regarding effects of diabetes pharmacotherapy, by drug class and/or by clinical indication, on the musculoskeletal health of persons with diabetes.

Diabetes Mellitus-induced Bone Fragility

Accumulating evidence has shown that the risk of osteoporotic fractures is increased in patients with diabetes mellitus (DM). Thus, DM-induced bone fragility has been recently recognized as a diabetic complication. Because the fracture risk is independent of the reduction in bone mineral density, deterioration of the bone quality may be the main cause of bone fragility. Although its mechanism remains poorly understood, accumulated collagen cross-links of advanced glycation end-products (AGEs) and dysfunctions of osteoblast and osteocyte may be involved. Previous studies have suggested that various diabetes-related factors, such as chronic hyperglycemia, insulin, insulin-like growth factor-I, AGEs, and homocysteine, are associated with the risk of bone fragility caused by impaired bone formation and bone remodeling. Furthermore, several anti-diabetic drugs are known to affect bone metabolism and fracture risk. We herein review the association between DM and fracture risk as well as the mechanism of DM-induced bone fragility based on recent evidence.

A model of calcium transport and regulation in the proximal tubule

The objective of this study was to examine theoretically how Ca²⁺ reabsorption in the proximal tubule (PT) is modulated by Na⁺ and water fluxes, parathyroid hormone (PTH), Na⁺-glucose cotransporter (SGLT2) inhibitors, and acetazolamide. We expanded a previously published mathematical model of water and solute transport in the rat PT (Layton AT, Vallon V, Edwards A. Am J Physiol Renal Physiol 308: F1343–F1357, 2015) that did not include Ca²⁺. Our results indicate that Ca²⁺ reabsorption in the PT is primarily driven by the transepithelial Ca²⁺ concentration gradient that stems from water reabsorption, which is itself coupled to Na⁺ reabsorption. Simulated variations in permeability or transporter activity elicit opposite changes in paracellular and transcellular Ca²⁺ fluxes, whereas a simulated decrease in filtration rate lowers both fluxes. The model predicts that PTH-mediated inhibition of the apical Na⁺/H⁺ exchanger NHE3 reduces Na⁺ and Ca²⁺ transport to a similar extent. It also suggests that acetazolamide- and SGLT2 inhibitor-induced calciuria at least partly stems from reduced Ca²⁺ reabsorption in the PT. In addition, backleak of phosphate (PO₄) across tight junctions is predicted to reduce net PO₄ reabsorption by ~20% under normal conditions. When transcellular PO₄ transport is substantially reduced by PTH, paracellular PO₄ flux is reversed and contributes significantly to PO₄ reabsorption. Furthermore, PTH is predicted to exert an indirect impact on PO₄ reabsorption via its inhibitory action on NHE3. This model thus provides greater insight into the mechanisms that modulate Ca²⁺ and PO₄ reabsorption in the PT.

Hesperidin, a plant flavonoid accelerated the cutaneous wound healing in streptozotocin-induced diabetic rats: Role of TGF-ß/Smads and Ang-1/Tie-2 signaling pathways

Background: Delayed wound healing is a diverse, multifactorial, complex and inter-related complication of diabetes resulting in significant clinical morbidity. Hesperidin possesses potent antidiabetic and wound healing activity.

Aim: To evaluate the potential of hesperidin against experimentally induced diabetes foot ulcers.

Methods: Diabetes was induced experimentally by streptozotocin (STZ, 55 mg/kg, i.p.) in Sprague Dawley rats (180-220 g) and wounds were created on the dorsal surface of the hind paw of rats. Hesperidin (25, 50 and 100 mg/kg, p.o.) was administered for 21 days after wound stabilization. Various biochemical, molecular and histopathological parameters were evaluated in wound tissue.

Results: STZ-induced decrease in body weight and increase in blood glucose, food, and water intake was significantly (p < 0.05) inhibited by hesperidin (50 and 100 mg/kg) treatment. It showed a significant increase (p < 0.05) in percent wound closure and serum insulin level. The STZ-induced decrease in SOD and GSH level, as well as elevated MDA and NO levels, were significantly (p < 0.05) attenuated by hesperidin (50 and 100 mg/kg) treatment. Intraperitoneal administration of STZ caused significant down-regulation in VEGF-c, Ang-1, Tie-2, TGF-β and Smad 2/3 mRNA expression in wound tissues whereas hesperidin (50 and 100 mg/kg) treatment showed significant up-regulation in these mRNA expressions. STZ-induced alteration in would architecture was also attenuated by hesperidin (50 and 100 mg/kg) treatment.

Conclusion: Together, treatment with hesperidin accelerate angiogenesis and vasculogenesis via up-regulation of VEGF-c, Ang-1/Tie-2, TGF-β and Smad-2/3 mRNA expression to enhance wound healing in chronic diabetic foot ulcers.

The safety of gliptins : updated data in 2018

INTRODUCTION

Dipeptidyl peptidase-4 inhibitors (DPP-4is) are generally considered as glucose-lowering agents with a safe profile in type 2 diabetes.

AREAS COVERED

An updated review of recent safety data from randomised controlled trials, observational studies, meta-analyses, pharmacovigilance reports regarding alogliptin, linagliptin, saxagliptin, sitagliptin, and vildagliptin, with a special focus on risks of hypoglycemia, pancreatitis and pancreatic cancer, major cardiovascular events, hospitalisation for heart failure and other new safety issues, such as bone fractures and arthralgia. The safety of DPP-4i use in special populations, elderly patients, patients with renal impairment, liver disease or heart failure, will also be discussed.

EXPERT OPINION

The good tolerance/safety profile of DPP-4is has been largely confirmed, including in more fragile populations, with no gastrointestinal adverse effects and a minimal risk of hypoglycemia. DPP-4is appear to be associated with a small increased incidence of acute pancreatitis in placebo-controlled trials, although most observational studies are reassuring. Most recent studies with DPP-4is do not confirm the increased risk of hospitalisation for heart failure reported with saxagliptin in SAVOR-TIMI 53, but further post-marketing surveillance is still recommended. New adverse events have been reported such as arthralgia, yet a causal relationship remains unclear.