Dapagliflozin Attenuates Hyperglycemia Related Osteoporosis in ZDF Rats by Alleviating Hypercalciuria

Relevance of Sugar Transport across the Cell Membrane

Sugar transport through the plasma membrane is one of the most critical events in the cellular transport of nutrients; for example, glucose has a central role in cellular metabolism and homeostasis. The way sugars enter the cell involves complex systems. Diverse protein systems participate in the membrane traffic of the sugars from the extracellular side to the cytoplasmic side. This diversity makes the phenomenon highly regulated and modulated to satisfy the different needs of each cell line. The beautiful thing about this process is how evolutionary processes have diversified a single function: to move glucose into the cell. The deregulation of these entrance systems causes some diseases. Hence, it is necessary to study them and search for a way to correct the alterations and utilize these mechanisms to promote health. This review will highlight the various mechanisms for importing the valuable sugars needed to create cellular homeostasis and survival in all kinds of cells.

The risk of all-cause death with dapagliflozin versus placebo: a systematic review and meta-analysis of phase III randomized controlled trials

BACKGROUND

Dapagliflozin has proven cardioprotective and nephroprotective effects. However, the risk of all-cause death with dapagliflozin remains unclear.

RESEARCH DESIGN AND METHODS

We performed a meta-analysis of phase III randomized controlled trials (RCTs) for the risk of all-cause death and safety events with dapagliflozin compared to placebo. PubMed and EMBASE were searched from inception to 20 September 2022.

RESULTS

Five trials were included in the final analysis. Compared with the placebo, dapagliflozin demonstrated an 11.2% reduction in the risk of all-cause death (OR 0.88, 95% CI 0.81-0.94). No statistically significant difference in urinary tract infection (OR: 0.95, 95% CI: 0.78 to 1.17), bone fracture (OR: 1.06, 95% CI: 0.94 to 1.20), and amputation (OR: 1.01, 95% CI: 0.82 to 1.23) was observed between patients treated with dapagliflozin and placebo. Compared with placebo, dapagliflozin was associated with a significant reduction in acute kidney injury (OR: 0.71, 95% CI: 0.60 to 0.83), and increased the risk of genital infection (OR: 8.21, 95% CI: 4.19 to 16.12).

CONCLUSIONS

Dapagliflozin was associated with significantly reduced all-cause death and increased genital infection. Dapagliflozin was safe concerning urinary tract infection, bone fracture, amputation, and acute kidney injury, compared with the placebo.

The miRNA-144-5p/IRS1/AKT axis regulates the migration, proliferation, and mineralization of osteoblasts: A mechanism of bone repair in diabetic osteoporosis

Diabetic osteoporosis (DOP) is a disorder of bone metabolism induced by multiple mechanisms. Previous studies have revealed that microRNAs (miRNAs) play crucial roles in bone metabolism. MiRNA-144-5p has been proven to participate in the regulation of osteoblast activities; however, its specific mechanism in DOP has not been elucidated. This study investigated whether high glucose (HG) inhibited osteoblasts by regulating miRNA-144-5p. Our results showed that HG inhibited bone formation not only in vivo but also in vitro. We observed that HG severely hindered the migration, proliferation and mineralization of osteoblasts, while miRNA-144-5p was upregulated by way of the cell counting kit-8 assay, wound healing assay, alkaline phosphatase (ALP) activity assay and alizarin red staining. Double luciferase reporter experiments showed that miRNA-144-5p directly targeted insulin receptor substrate 1 (IRS1). The IRS1/AKT signaling pathway is closely related to osteoblasts' migration, proliferation, and mineralization. Silencing miRNA-144-5p promoted the mRNA, and protein expression of IRS1, thereby letting the expression of total AKT down, and then preventing phosphorylation of AKT into the nucleus to regulate migration, proliferation, and mineralization genes of osteoblasts. In conclusion, this study indicated that HG regulated the migration, proliferation, and mineralization of osteoblasts via the miRNA-144-5p/IRS1/AKT axis, which suggested a possible mechanism for DOP pathology.

Unfavorable effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors on the skeletal system of nondiabetic rats

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of antidiabetic drugs, acting by inhibiting the reabsorption of glucose in the kidneys. They turned out to improve cardiovascular and renal outcomes not only in patients with type 2 diabetes but also in nondiabetic patients. At present, they are more and more widely used in patients without diabetes. Since there were concerns that SGLT2 inhibitors may increase fracture risk in diabetes, the aim of the study was to examine the effect of dapagliflozin and canagliflozin on the musculoskeletal system of nondiabetic, healthy rats. The experiments were carried out on mature female rats, divided into the control rats and rats treated with dapagliflozin (1.4 mg/kg p.o.) or canagliflozin (4.2 mg/kg p.o.) for 4 weeks. Serum bone turnover markers, skeletal muscle strength and mass, bone mass, density, histomorphometric parameters and mechanical properties were determined. Administration of the drugs did not affect the skeletal muscle mass and strength. There was no effect on serum bone turnover markers, and bone mass and composition. However, administration of both drugs resulted in disorders of cancellous bone microarchitecture and worsening of bone mechanical properties. In conclusion, both SGLT2 inhibitors unfavorably affected the skeletal system of healthy rats.

Mapping Knowledge Landscapes and Emerging Trends of the Links Between Bone Metabolism and Diabetes Mellitus: A Bibliometric Analysis From 2000 to 2021

Background

Diabetes mellitus (DM) have become seriously threatens to human health and life quality worldwide. As a systemic metabolic disease, multiple studies have revealed that DM is related to metabolic bone diseases and always induces higher risk of fracture. In view of this, the links between bone metabolism (BM) and DM (BMDM) have gained much attention and numerous related papers have been published. Nevertheless, no prior studies have yet been performed to analyze the field of BMDM research through bibliometric approach. To fill this knowledge gap, we performed a comprehensive bibliometric analysis of the global scientific publications in this field.

Methods

Articles and reviews regarding BMDM published between 2000 and 2021 were obtained from the Web of Science after manually screening. VOSviewer 1.6.16, CiteSpace V 5.8.R3, Bibliometrix, and two online analysis platforms were used to conduct the bibliometric and visualization analyses.

Results

A total of 2,525 documents including 2,255 articles and 270 reviews were retrieved. Our analysis demonstrated a steady increasing trend in the number of publications over the past 22 years (R2 = 0.989). The United States has occupied the leading position with the largest outputs and highest H-index. University of California San Francisco contributed the most publications, and Schwartz AV was the most influential author. Collaboration among institutions from different countries was relatively few. The journals that published the most BMDM-related papers were Bone and Osteoporosis International. Osteoporosis and related fractures are the main bone metabolic diseases of greatest concern in this field. According to co-cited references result, “high glucose environment,” “glycation end-product” and “sodium-glucose co-transporter” have been recognized as the current research focus in this domain. The keywords co-occurrence analysis indicated that “diabetic osteoporosis,” “osteoarthritis,” “fracture risk,” “meta-analysis,” “osteogenic differentiation,” “bone regeneration,” “osteogenesis,” and “trabecular bone score” might remain the research hotspots and frontiers in the near future.

Conclusion

As a cross-discipline research field, the links between bone metabolism and diabetes mellitus are attracting increased attention. Osteoporosis and related fractures are the main bone metabolic diseases of greatest concern in this field. These insights may be helpful for clinicians to recognize diabetic osteopenia and provide more attention and support to such patients.

Glucagon-like peptide-1 attenuates diabetes-associated osteoporosis in ZDF rat, possibly through the RAGE pathway

Background

Diabetes-associated osteoporosis are partly caused by accumulation of advanced glycation endproducts (AGEs). Glucagon-like peptide-1 (GLP-1) has been shown to regulate bone turnover. Here we explore whether GLP-1 receptor agonist (GLP1RA) can have a beneficial effect on bone in diabetes by ameliorating AGEs.

Methods

In the present study, we evaluated the effects of the GLP-1 receptor agonist liraglutide, insulin and dipeptidyl peptidase-4 inhibitor saxagliptin on Zucker diabetic fatty rats. Meanwhile, we observed the effect of GLP-1 on AGEs-mediated osteoblast proliferation and differentiation and the signal pathway.

Results

Liraglutide prevented the deterioration of trabecular microarchitecture and enhanced bone strength. Moreover, it increased serum Alpl, Ocn and P1NP levels and decreased serum CTX. In vitro we confirmed that GLP-1 could attenuate AGEs-mediated damage in osteogenic proliferation and differentiation. Besides, GLP-1 down-regulated the ROS that caused by AGEs and the mRNA and protein expression of Rage .

Conclusions

Altogether, our findings suggest that GLP-1 receptor agonist promotes osteoblastogenesis and suppresses bone resorption on obese type 2 diabetic rats to a certain degree. The mechanism of these effects may be partly mediated by AGEs-RAGE-ROS pathway via the interaction with GLP-1 receptor.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05396-5.

Formulation and evaluation of SGLT2 inhibitory effect of a polyherbal mixture inspired from Ayurvedic system of medicine

Background and aim

The ingredients viz., Artemisia roxburghiana, Cissampelos pareira, Stephania glabra, Drimia indica, Roylea cinerea, Tinospora sinensis and Curcuma longa of the present formulation are used to treat diabetes in the Indian traditional medical system. Adopting the concept of multiple herbal mixtures for better therapeutic effects from the ancient Ayurvedic text Sarangdhar Samhita, the present study aimed to develop a polyherbal formulation (PHF) of seven herbs and to evaluate its sodium-glucose cotransporter protein-2 (SGLT2) inhibitory effect on type 2 diabetic rats.

Experimental procedure

Streptozotocin (STZ) (60 mg/kg) and nicotinamide (NAM) (120 mg/kg) were intraperitoneally administered to induce type 2 diabetes in Wistar rats. The animals were divided into 5 groups viz. normal control, diabetic control, positive control (dapagliflozin at 0.1 mg/kg) and two test groups (PHF at 250 and 500 mg/kg). Various parameters including blood glucose, serum glutamic pyruvic transaminase (SGPT), serum glutamic-oxaloacetic transaminase (SGOT), bilirubin, triglycerides and creatinine were measured.

Results and conclusion

The treatment with PHF (250 and 500 mg/kg) showed a significant (p < 0.05) decrease in blood glucose levels by 56.37% and 58.17%, respectively. The levels of SGOT, SGPT and bilirubin were significantly reduced in PHF-fed diabetic rats. Histopathological examination revealed no major changes in the treated groups as compared to the normal control. The molecular docking study showed strong binding of β-sitosterol, insulanoline, warifteine, dehydrocorydalmine, taraxerol acetate, lupeol, corydalmine and luteolin to SGLT2 protein. The present study concludes that PHF has promising antidiabetic activity via inhibiting SGLT2 protein without showing any adverse effects.

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Polyherbal formulation is prepared with seven traditional herbs used in diabetes.

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It showed antihyperglycemic effect in streptozotocin-nicotinamide-induced diabetic rats.

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Liver and kidney functions were found normal in the treated diabetic rats.

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Histopathology of the liver, kidney and pancreas did not show any toxic sign after the treatment.

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Molecular docking study showed the SGLT2 inhibitory activity of bioactive compounds.

Canagliflozin, an SGLT2 inhibitor, corrects glycemic dysregulation in TallyHO model of T2D but only partially prevents bone deficits

Higher fracture risk in type 2 diabetes (T2D) is attributed to disease-specific deficits in micro-structural and material properties of bone, although the primary cause is not yet established. The TallyHO (TH) mouse is a polygenic model of early-onset T2D and obesity analogous to adolescent-onset T2D in humans. Due to incomplete penetrance of the phenotype, ~25% of male TH mice never develop hyperglycemia, providing a strain-matched, non-diabetic control. Utilizing this model of T2D, we examined the impact of glucose-lowering therapy with canagliflozin (CANA) on diabetic bone. Male TH mice with or without hyperglycemia (High BG, Low BG) were monitored from ~8 to 20 weeks of age, and compared to age-matched, male, TH mice treated with CANA from ~8 to 20 weeks of age. At 20 weeks, untreated TH mice with high BG [High BG: 687 ± 106 mg/dL] exhibited lower body mass, decrements in cortical bone of the femur (decreased cross-sectional area and thickness; increased porosity) and in trabecular bone of the femur metaphysis and L6 vertebra (decreased bone volume fraction, thickness, and tissue mineral density), as well as decrements in cortical and vertebral bone strength (decreased yield force and ultimate force) when compared to untreated TH mice with low BG [Low BG: 290 ± 98 mg/dL; p < 0.0001]. CANA treatment was metabolically advantageous, normalizing body mass, BG and HbA1c to values comparable to the Low BG group. With drug-induced glycemic improvement, cortical area and thickness were significantly higher in the CANA than in the High BG group, but deficits in strength persisted with lower yield force and yield stress (partially independent of bone geometry) in the CANA group. Additionally, CANA only partially prevented the T2D-related loss in trabecular bone volume fraction. Taken together, these findings suggest that the ability of CANA to lower glucose and normalized glycemic control ameliorates diabetic bone disease but not fully.

Update on: effects of anti-diabetic drugs on bone metabolism

INTRODUCTION

Preclinical, clinical, and population-based studies have provided evidence that anti-diabetic drugs affect bone metabolism and may affect the risk of fracture in diabetic patients.

AREAS COVERED

An overview of the skeletal effects of anti-diabetic drugs used in type 2 diabetes is provided. Searches on AdisInsight, PubMed, and Medline databases were conducted up to 1^st July 2020. The latest evidence from randomized clinical trials and population-based studies on the skeletal safety of the most recent drugs (DPP-4i, GLP-1RA, and SGLT-2i) is provided.

EXPERT OPINION

Diabetic patients present with a higher risk of fracture for a given bone mineral density suggesting a role of bone quality in the etiology of diabetic fracture. Bone quality is difficult to assess in human clinical practice and the use of preclinical models provides valuable information on diabetic bone alterations. As several links have been established between bone and energy homeostasis, it is interesting to study the safety of anti-diabetic drugs on the skeleton. So far, evidence for the newest molecules suggests a neutral fracture risk, but further studies, especially in different types of patient populations (patients at risk or with history of cardiovascular disease, renal impairment, neuropathy) are required to fully appreciate this matter.

The Hyperglycemia and Hyperketonemia Impaired Bone Microstructures: A Pilot Study in Rats

Though diabetes mellitus (DM) is one of the known causes of osteoporosis, it is also realized that ketogenic diet (KD), an effective regimen for epilepsy, impairs bone microstructures. However, the similarities and differences of effects between these two factors are still unknown. The purpose of this study is to identify different effects between hyperglycemia and hyperketonemia, which are manifestations of DM and KD, on bone in rats. Thirty male Sprague-Dawley rats were randomly divided into three groups: the sham, DM, and KD groups. Hyperglycemia was achieved by intravenous injection of streptozotocin in DM group, while hyperketonemia was induced by application of ketogenic diet (carbohydrates-to-fat as 1:3) in KD group. The body weight, blood ketone body, and blood glucose were recorded, and the bone turnover markers, bone length, bone microstructures, bone biomechanics and histomorphology were measured after 12 weeks intervention. Compared with the control and KD groups, a significant body weight loss was found in the DM group, and the bone lengths of tibia and femur of the group were shortened. The blood glucose and blood ketone were noticeably increased in the DM and KD rats, respectively. Microstructures and properties of cancellous bone were significantly deteriorated in both the DM and KD groups compared with the sham group, as the bone volumes were decreased and the bone trabecula structures were disturbed. Meanwhile, the thickness and strength of cortical bone was reduced more in the DM group than those in the sham and KD groups. The HE staining showed that bone trabecula was significantly decreased in both the DM and KD groups, and more adipose tissue was observed in the KD rats. The activity of osteoblasts was decreased more in both the KD and DM groups than that in the sham group, while the activity of osteoclasts of the two groups was remarkably increased. The present study indicates that both hyperglycemia and hyperketonemia have adverse effects on bone. Therefore, it is worth paying more attention to the bone status of patients with hyperglycemia and hyperketonemia in clinic.