Diabetes and bone: biological and environmental factors

Enzyme-delivery Metal-organic Framework Composite Coatings for Restoration of Hyperglycemia-damaged Osteoblast Differentiation

There is a significant clinical need to develop effective treatments for bone defects in patients with diabetes mellitus (DM), as they are at higher risk of fractures and impaired healing. Guided bone tissue engineering using biocompatible and biodegradable polymers is a promising approach. However, current diabetic bone regenerative therapies often fail due to the accumulation of advanced glycation products, which can affect the integration of traditional tissue engineering scaffolds with native bone. Therefore, novel approaches are needed to improve the efficacy of diabetic bone regeneration. This study presents a proof-of-concept development of a multifunctional polymer composite coating tailored towards restoring diabetes-related damage in osteoblast differentiation. Our composite system involves 3D-printed poly(caprolactone fumarate) (PCLF) and poly(caprolactone) (PCL) blend scaffolds coated with multifunctional chitosan methacrylate (chiMA). The chiMA coating is embedded with a sustained-release formulation of glucose oxidase (GOx) from MIL-127 metal-organic frameworks making the coating a stimuli-responsive biomolecule delivery system. The multifunctional coating is designed for the sustained release of GOx and sodium pyruvate for in vitro glucose modulation and oxidative stress reduction, respectively. We propose that sustained release of GOx from MIL-127 embedded chiMA coatings can modulate the high glucose (HG) cellular milieu towards normal glucose (NG), enhancing osteoblast (OB) differentiation via downstream effects. Our results show successful synthesis of MIL-127, encapsulation of GOx, and fabrication of composite coating on the PCLF/PCL scaffolds with effective enzyme activity measured as a function of lowering glucose concentration in HG media for 144 h to normal levels. In vitro evaluation of OB viability, attachment, proliferation, and differentiation showed an overall decrease in cellular activity in HG conditions, which was restored through the glucose-modulating functionality of the GOx-releasing MIL-127 coatings. Our results also presented preliminary evidence of a statistical correlation between DM-related gene markers and osteogenic markers in vitro that requires further exploration. Although this proof-of-concept study holds promise for advancing precision biomaterials development for diabetic tissue engineering and meeting the unmet clinical need for effective treatments and warrants future in vivo evaluation of the composite coating and molecular biology understanding of correlations between DM and osteogenic markers.

Alkaline Water Mitigates Bone Loss in Streptozotocin-Induced Type II Diabetic Rats

Background A decline in bone mineral density is a defining feature of osteoporosis, which is a prevalent bone complication associated with diabetes. This study aims to shed light on the protective effect of Zamzam water (ZW), a famous alkaline water, on diabetes-induced osteoporosis. Methodology Of a total of 40 male rats, 10 male rats each were divided into the following four groups: group I (normal control rats), group II (ZW group), group III (diabetic rats), and group IV (DM + ZW). Anteroposterior and lateral X-rays were taken of the rats in each group before the end of the experiment. The study assessed serum levels of inflammatory markers including interleukin 6, interleukin-1 beta, and tumor necrosis factor-alpha; bone formation markers including osteocalcin (OC); alkaline phosphatase (ALP); and bone resorption markers including the N-terminal telopeptide of collagen type I (NTX-1), bone deoxypyridinoline (DPD), and tartrate-resistant acid phosphatase 5b (TRAP-5b). Results Rats with diabetes who consumed ZW exhibited a significant (p < 0.001) increase in OC and ALP bone formation markers and a decrease in NTX-1, DPD, and TRAP-5b bone resorption markers, with improvements in the X-ray image of the vertebral column at the L6 vertebra level. Conclusions ZW improved diabetes-induced osteoporosis in rats by enhancing osteoblastic activity and downregulating osteoclastic activity.

Metformin enhances the osteogenic activity of rat bone marrow mesenchymal stem cells by inhibiting oxidative stress induced by diabetes mellitus: an in vitro and in vivo study

PURPOSE

The purpose of this study was to determine whether metformin (MF) could alleviate the expresssion of reactive oxygen species (ROS) and improve the osteogenic ability of bone marrow mesenchymal stem cells derived from diabetic rats (drBMSCs) in vitro, and to evaluate the effect of MF on the ectopic osteogenesis of drBMSCs in a nude mouse model in vivo.

METHODS

BMSCs were extracted from normal and diabetic rats. In vitro, a cell viability assay (Cell Counting Kit-8), tests of alkaline phosphatase (ALP) activity, and western blot analysis were first used to determine the cell proliferation and osteogenic differentiation of drBMSCs that were subjected to treatment with different concentrations of MF (0, 50, 100, 200, 500 μM). The cells were then divided into 5 groups: (1) normal rat BMSCs (the BMSCs derived from normal rats group), (2) the drBMSCs group, (3) the drBMSCs + Mito-TEMPO (10 μM, ROS scavenger) group, (4) the drBMSCs + MF (200 μM) group, and (5) the drBMSCs + MF (200 μM) + H₂O₂ (50 μM, ROS activator) group. Intracellular ROS detection, a senescence-associated β-galactosidase assay, ALP staining, alizarin red staining, western blotting, and immunofluorescence assays were performed to determine the effects of MF on oxidative stress and osteogenic differentiation in drBMSCs. In vivo, the effect of MF on the ectopic osteogenesis of drBMSCs was evaluated in a nude mouse model.

RESULTS

MF effectively reduced ROS levels in drBMSCs. The cell proliferation, ALP activity, mineral deposition, and osteogenic-related protein expression of drBMSCs were demonstrably higher in the MF-treated group than in the non-MF-treated group. H₂O₂ inhibited the effects of MF. In addition, ectopic osteogenesis was significantly increased in drBMSCs treated with MF.

CONCLUSIONS

MF promoted the proliferation and osteogenic differentiation of drBMSCs by inhibiting the oxidative stress induced by diabetes and enhenced the ectopic bone formation of drBMSCs in nude mice.

The Therapeutic Effects and Mechanisms of Salidroside on Cardiovascular and Metabolic Diseases: An Updated Review

The increasing incidence of metabolic and cardiovascular diseases has severely affected global human health and life safety. In recent years, some effective drugs with remarkable curative effects and few side effects found in natural compounds have attracted attention. Salidroside (SAL), a phenylpropane glycoside, is the main active ingredient of the plateau plant Rhodiola. So far, many animal experiments proved that SAL has good biological activity against some metabolic and cardiovascular diseases. However, most of these reports are scattered. This review systematically summarizes the pharmacological progress of SAL in the treatment of several metabolic (e. g., diabetes and non-alcoholic fatty liver disease) and cardiovascular (e. g., atherosclerosis) diseases in a timely manner to promote the clinical application and basic research of SAL. Accumulating evidence proves that SAL has beneficial effects on these diseases. It can improve glucose tolerance, insulin sensitivity, and β-cell and liver functions, and inhibit adipogenesis, inflammation and oxidative stress. Overall, SAL may be a valuable and potential drug candidate for the treatment of metabolic and cardiovascular diseases. However, more studies especially clinical trials are needed to further confirm its therapeutic effects and molecular mechanisms.

Zinc Supplementation Increased Bone Mineral Density, Improves Bone Histomorphology, and Prevents Bone Loss in Diabetic Rat

Diabetic osteoporosis (DOP) is a complication of diabetes, with the characteristics of bone mineral density (BMD) reduction and bone structure destruction. Zinc was reported has a benefit effect on postmenopausal osteoporosise, it was also has hypoglycemic effect, whether zinc was beneficial on diabetes-induced osteoporosis has not been reported. So in the present study, we established a diabetic rat model by streptozotocin injection (60 mg/kg), and administered zinc sulfate by oral gavage to investigate the protective effects of zinc on DOP and the underline possible mechanism. Thirty six Sprague Dawley rats were divided into T1DM group (diabetic rats), control group (vehicle treatment), and T1DM-Zinc group (diabetic rats administered zinc sulfate 0.25 mg/kg by oral gavage). The bone histomorphological parameters, serum bone metabolism markers (including ALP, OPG, RUNX 2, and RANKL), BMD, and bone marrow adipocyte numbers were detected after eight weeks of zinc sulfate treatment. The results showed zinc sulfate administration (0.25 mg/kg/d) decreased blood glucose, increased the BMD, decreased serum ALP, and RANKL, increased serum OPG and RUNX 2 levels, as well as OPG/RANKL ratio of T1DM rats. Meanwhile, the bone histomorphological parameters, bone marrow adipocytes numbers were returned to be normal. The RUNX 2, and OPG mRNA expression levels in bone tissues of T1DM-Zinc group rats were increased after zinc sulfate treatment compared with the diabetic rats (P < 0.05). Those indicating that zinc sulfate can prevent DOP, the protective mechanism were mainly related to its hypoglycemic effect, bone marrow lipogenesis inhibition effect, OPG/RANKL ratio and RUNX 2 up-regulation effect.

Linear and Non-linear Correlations Between Serum Phosphate Level and Bone Mineral Density in Type 2 Diabetes

Introduction: Serum phosphate plays an important role in bone mineralization and might be a risk factor for many bone diseases. Patients with T2D usually have low serum phosphate level due to diet control, osmotic diuresis, and insulin stimulation. Current studies have discussed the linear association between serum phosphate and bone mineral density (BMD). Objective: We aimed to analyze both the linear and non-linear correlations between serum phosphate and BMD in patients with type 2 diabetes (T2D). Methods: We included 1,469 patients with T2D and obtained their basic information, laboratory measurements, and BMD data. Multivariate adjusted linear regression was used to analyze the linear associations, and we applied a two-piecewise linear regression model using a smoothing function to examine the non-linear association. Results: No linear correlation was found between serum phosphate and BMD in patients with T2D. In women with T2D, we found a non-linear correlation between serum phosphate level and femur neck or total hip BMD. When serum phosphate was <1.3 mmol/L, it was positively associated with femur neck and total hip BMD, whereas when phosphate was >1.3 mmol/L, it was negatively associated with femur neck BMD. Conclusions: In men with T2D, serum phosphate level was not associated with BMD. However, in women with T2D, we found a non-linear correlation between serum phosphate and femur neck or total hip BMD.

Current Knowledge Regarding the Interaction Between Oral Bone Metabolic Disorders and Diabetes Mellitus

Diabetes mellitus, a major chronic disease affecting human health, has been increasing in prevalence in recent years. Diabetes mellitus can cause bone metabolic disorders in patients, leading to osteoporosis, a higher risk of traumatic fracture, and other bone diseases. Bone metabolic disorders in the oral cavity principally manifest as periodontitis, loss of alveolar bone, and failure of implant osseointegration. In recent years, numerous studies have shown that there is a complex interaction between bone metabolic disorders and diabetes mellitus. This paper reviews the adverse effects of diabetes on oral bone metabolism disorders such as alveolar osteoporosis and bone loss in patients with periodontitis, discusses the potential mechanisms of diabetic bone loss, and suggests potential ways to prevent and treat oral bone loss in patients with diabetes mellitus.

Icariin Prevents Diabetes-Induced Bone Loss in Rats by Reducing Blood Glucose and Suppressing Bone Turnover

Diabetic Osteoporosis (DOP) is a common metabolic bone disease, characterized by decreased bone mineral density (BMD) and destruction of bone microstructure. It has been reported that icariin is beneficial for estrogen deficiency-induced osteoporosis, and alcohol-induced osteoporosis; whether icariin has protective effects on diabetes-induced osteoporosis has not been reported. In this study, a rat model of diabetic osteoporosis was established by streptozotocin injection, the bone protective effects and potential mechanism of icariin on diabetes-induced bone loss was observed. Thirty 8-week-old female Sprague Dawley rats were divided into control group (vehicle treatment), T1DM (diabetic) group and T1DM-icariin (ICA) group (diabetic rats treated with icariin), 10 rats in each group. The bone histomorphometry parameters, bone mineral density (BMD), serum bone turnover markers, and bone marrow adipogenesis were analyzed after 8 weeks of icariin administration. The results showed consumption of icariin at a doses of 100 mg kg⁻¹ decreased blood glucose, and increased the BMD of diabetic rats. Icariin effectively decreased serum bone turnover marker levels, including CTX-1, ALP, TRACP 5b, osteocalcin, and PINP. Meanwhile, the bone histomorphometry parameters, the number of osteoclasts per bone perimeter were turned to be normal level, and the icariin treatment suppressed bone marrow adipogenesis. The runt-related transcription factor 2 (RUNX 2), as well as the osteoprotegerin (OPG)/receptor activator of nuclear factor-κ B ligand (RANKL) ratio in serum and bone tissues were increased significantly after icariin treatment in diabetic rats. All of the above indicate that oral administration of icariin can prevent diabetic osteoporosis; the effect is mainly related to its ability to reduce blood glucose, inhibit bone turnover and bone marrow adipogenesis, as well as up-regulate bone RUNX 2, and OPG expression.

Tetrahydroxy stilbene glucoside protected against diabetes-induced osteoporosis in mice with streptozotocin-induced hyperglycemia

Tetrahydroxy stilbene glucoside (TSG), an active component from medicinal herb Polygonum multiflorum Thunb, could block the activity of the tissue renin-angiotensin system (RAS), which plays a critical role in development of diabetic osteoporosis. This study aimed to determine if TSG therapy could alleviate bone deteriorations in diabetic mouse model induced by streptozotocin. The diabetic mice showed the loss of trabecular bone mass and the changes of trabecular bone microarchitectural parameters as well as the increase in amount of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts at the distal metaphysis of femur when compared with those of nondiabetic mice. Treatment with TSG significantly elevated calcium content in serum and bone and improved biological parameters of trabecular bone, accompanied by increasing messenger RNA (mRNA) expression of RUNX-2, COL-I, and OCN and protein expression of β-catenin as well as down-regulating protein expression of RAS components including renin and AT1R. In addition, TSG repressed diabetes-induced decrease in ratio of OPG/RANKL expression and increase in sclerostin expression in bone. The similar effects of TSG on osteoblasts-specific genes were found in MC3T3-E1 cells. Taken together, the present study demonstrated the osteopreserve effects of TSG in diabetic mice, and the underlying mechanism might be attributed to its regulation on osteogenesis and osteoclastogenesis.

Different bone sites-specific response to diabetes rat models: Bone density, histology and microarchitecture

BACKGROUND AND PURPOSE

Diabetes mellitus (DM) is the most common metabolic disorder that is characterized by hyperglycemia, it can be categorized by T1DM and T2DM. T1DM is also reported to cause bone loss. However, most reports regarding this aspect of T1DM have only investigated a single site; a comparison of bone loss from different areas of the body is still lacking.

METHODS

Thirty-five 12-week-old Sprague Dawley® (SD) rats were separated to seven groups. Five rats were euthanized without any surgery at 0 weeks for histological examination and determination of baseline characteristics. In 15 of the rats, DM was induced via Streptozotocin (STZ)-injection, and they were separated to 3 groups (4 weeks, 8 weeks and 12 weeks after STZ-injection). The remaining 15 rats were used as the control group (4 weeks, 8 weeks and 12 weeks after saline-injection). We tested bone-mass loss at four skeletal sites, the tibia, the femur greater trochanter, the spine, and the mandibular bones using micro-computed tomography (CT) and histological tests.

RESULTS

Tibia was influenced the most obvious(BV/TV decreased by 27.3%, 52.5%, and 81.2% at 4 weeks, 8 weeks, and 12 weeks, respectively. p<0.05). In contrast, the other three sites were influenced to a lesser extent and bone loss became prominent at a later time point according to the histological and micro-CT tests(Femur: BV/TV did not decrease significantly at the first month or second month. However, and decreased by 49.4% at the third month, P<0.05. Mandible: the BV/TV only decreased by 6.5% at 1 month after STZ-injection. There was still a significant difference between the second and third months. The BV/TV decreased by 47.0% and 68.1% at 2 months and 3 months, respectively, (p<0.05) Spine: the BV/TV only decreased by 6.7%. However, significant change was observed in the spine at the second month and third month after STZ injection. The BV/TV decreased by 45.4% and 64.3%, respectively, p<0.05).

CONCLUSION

The results indicate that T1DM can severely influence the bone structure of the 4 skeletal sites. Further, areas with dense trabecular bones were influenced less and at a later time point in comparison to the tibial region.

CLINICAL RELEVANCE

Our research can serve as a guide to help increase the success rate of implant treatment, and help decrease the fracture risk in different bone types with greater accuracy.

Salidroside Improves Bone Histomorphology and Prevents Bone Loss in Ovariectomized Diabetic Rats by Upregulating the OPG/RANKL Ratio

Postmenopausal diabetic women have a high risk of fractures. Salidroside has preventive effects on estrogen deficiency-induced osteoporosis and has hypoglycemic effects on diabetes in rats. However, whether salidroside inhibits bone loss in postmenopausal diabetic patients is still unknown. Here, we established a rat model of osteoporosis to investigate the protective effects of salidroside on bone loss induced by ovariectomy combined with diabetes, also investigating the underlying mechanisms. Two-month-old female Sprague-Dawley rats were divided into three equal groups (10 rats in each group): control group (with sham operation, treated with drug vehicle); OVX/T1DM group (ovariectomized diabetic rats); OVX/T1DM-SAL group, comprising ovariectomized diabetic rats treated with salidroside (20 mg/kg body weight) by gavage. The results showed that after 60 consecutive days of treatment, the bone mineral density (BMD) of OVX/T1DM-SAL increased significantly compared with the OVX/T1DM group (p < 0.01). The level of serum bone turnover markers, including alkaline phosphatase (ALP), cross linked c-telopeptide of type I collagen (CTX-1), osteocalcin, N-terminal propeptide of type I procollagen (PINP), and tartrate-resistant acid phosphatase 5b (TRACP 5b) were all increased in the OVX/T1DM group compared with the control (p < 0.01), and those were decreased by salidroside treatment. Meanwhile, the bone histopathological changes were also attenuated, and the bone marrow adipogenesis was inhibited in salidroside treated rats. Moreover, protein and mRNA ratio of bone osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL) was upregulated in ovariectomized diabetic rats by salidroside treatment. The results above indicated that the protective effect of salidroside on bone loss induced by ovariectomy and diabetes was mainly due to its ability to suppress bone turnover, inhibit bone marrow adipogenesis, and up-regulate the OPG/RANKL ratio.

Multiple fractures and impaired bone metabolism in Wolfram syndrome: a case report

Wolfram Syndrome (WS) is a rare and lethal disease characterized by optic atrophy, diabetes mellitus, diabetes insipidus, and hearing loss. To date, osteoporotic related fractures have not been reported in affected patients. Here, we describe the case of a man affected by WS complicated by several bone fragility fractures. A 50-year-old Caucasian man was hospitalized because of tibia and fibula fractures. His clinical features included diabetes mellitus, diabetes insipidus, optic atrophy and deafness that were consistent with an unrecognized WS diagnosis, which was confirmed by the identification of a specific mutation in gene WFS1 encoding wolframin. Bone mineral density by phalangeal quantitative ultrasound demonstrated severe osteoporosis, with high serum levels of surrogate markers of bone turn-over. Previously unidentified rib fractures were also detected. To the best of our knowledge, this is the first report of osteoporotic related fractures in a patient affected by WS. Although no effective treatments are currently available to delay the progression of the disease, this case report suggests to evaluate fracture risk in the diagnostic work-up of WS.

Diabetic Osteoporosis: A Review of Its Traditional Chinese Medicinal Use and Clinical and Preclinical Research

Aim. The incidence of diabetic osteoporosis (DOP) is increasing due to lack of effective management over the past few decades. This review aims to summarize traditional Chinese medicine (TCM) suitability in the pathogenesis and clinical and preclinical management of DOP. Methods. Literature sources used were from Medline (Pubmed), CNKI (China Knowledge Resource Integrated Database), and CSTJ (China Science and Technology Journal Database) online databases. For the consultation, keywords such as diabetic osteoporosis (DOP), TCM, clinical study, animal experiment, toxicity, and research progress were used in various combinations. Around 100 research papers and reviews were visited. Results. Liver-spleen-kidney insufficiency may result in development of DOP. 18 clinical trials are identified to use TCM compound prescriptions for management of patients with DOP. TCM herbs and their active ingredients are effective in preventing the development of DOP in streptozotocin (STZ) and alloxan as well as STZ combined with ovariectomy insulted rats. Among them, most frequently used TCM herbs in clinical trials are Radix Astragali, Radix et Rhizoma Salviae Miltiorrhizae, Radix Rehmanniae Preparata, and Herba Epimedii. Some of TCM herbs also exhibit toxicities in clinical and preclinical research. Conclusions. TCM herbs may act as the novel sources of anti-DOP drugs by improving bone and glucolipid metabolisms. However, the pathogenesis of DOP and the material base of TCM herbs still merit further study.