Mechanisms involved in altered bone metabolism in diabetes: a narrative review

An investigation of composition, morphology, mechanical properties, and microdamage accumulation of human type 2 diabetic bone

This study investigates the biomechanics of type 2 diabetic bone fragility through a multiscale experimental strategy that considers structural, mechanical, and compositional components of ex vivo human trabecular and cortical bone. Human tissue samples were obtained from the femoral heads of patients undergoing total hip replacement. Mechanical testing was carried out on isolated trabecular cores using monotonic and cyclic compression loading and nanoindentation experiments, with bone microdamage analysed using micro-computed tomography (CT) imaging. Bone composition was evaluated using Raman spectroscopy, high-performance liquid chromatography, and fluorometric spectroscopy. It was found that human type 2 diabetic bone had altered mechanical, compositional, and morphological properties compared to non-type 2 diabetic bone. High-resolution micro-CT imaging showed that cores taken from the central trabecular region of the femoral head had higher bone mineral density (BMD), bone volume, trabecular thickness, and reduced trabecular separation. Type 2 diabetic bone also had enhanced macro-mechanical compressive properties under mechanical loading compared to non-diabetic controls, with significantly higher apparent modulus, yield stress, and pre-yield toughness evident, even when properties were normalised against the bone volume. Using nanoindentation, there were no significant differences in the tissue-level mechanical properties of cortical or trabecular bone in type 2 diabetic samples compared to controls. Through compositional analysis, higher levels of furosine were found in type 2 diabetic trabecular bone, and an increase in both furosine and carboxymethyl-lysine (an advanced glycation end-product) was found in cortical bone. Raman spectroscopy showed that type 2 diabetic bone had a higher mineral-to-matrix ratio, carbonate substitution, and reduced crystallinity compared to the controls. Together, this study shows that type 2 diabetes leads to distinct changes in both organic and mineral phases of the bone tissue matrix, but these changes did not coincide with any reduction in the micro- or macro-mechanical properties of the tissue under monotonic or cyclic loading.

Links among Obesity, Type 2 Diabetes Mellitus, and Osteoporosis: Bone as a Target

Obesity, type 2 diabetes mellitus (T2DM) and osteoporosis are serious diseases with an ever-increasing incidence that quite often coexist, especially in the elderly. Individuals with obesity and T2DM have impaired bone quality and an elevated risk of fragility fractures, despite higher and/or unchanged bone mineral density (BMD). The effect of obesity on fracture risk is site-specific, with reduced risk for several fractures (e.g., hip, pelvis, and wrist) and increased risk for others (e.g., humerus, ankle, upper leg, elbow, vertebrae, and rib). Patients with T2DM have a greater risk of hip, upper leg, foot, humerus, and total fractures. A chronic pro-inflammatory state, increased risk of falls, secondary complications, and pharmacotherapy can contribute to the pathophysiology of aforementioned fractures. Bisphosphonates and denosumab significantly reduced the risk of vertebral fractures in patients with both obesity and T2DM. Teriparatide significantly lowered non-vertebral fracture risk in T2DM subjects. It is important to recognize elevated fracture risk and osteoporosis in obese and T2DM patients, as they are currently considered low risk and tend to be underdiagnosed and undertreated. The implementation of better diagnostic tools, including trabecular bone score, lumbar spine BMD/body mass index (BMI) ratio, and microRNAs to predict bone fragility, could improve fracture prevention in this patient group.

La osteocalcina se asocia con la densidad mineral ósea y los polimorfismos del gen VDR en la diabetes tipo 1 y 2

Objetivos

El metabolismo óseo se encuentra alterado en la diabetes mellitus (DM). El objetivo de este estudio es evaluar la relación entre los marcadores de remodelado óseo (MRO), los polimorfismos en el gen receptor de la vitamina D (VDR) y la densidad mineral ósea (DMO) en la DM tipo 1 (T1D) y tipo 2 (T2D).

Métodos

Se incluyó a 165 pacientes (53 T1D y 112 T2D). La DMO se midió mediante absorciometría de rayos X de energía dual (DEXA). Se realizó un análisis de la osteocalcina (OC) en plasma, beta-CrossLaps (β-CTX), propéptido aminoterminal del procolágeno tipo 1 (P1NP) y los polimorfismos en el gen VDR.

Resultados

Se incluyó a 53 pacientes con T1D (41 años (31–48)) y 112 con T2D (60 años [51–66]). No se observaron diferencias estadísticamente significativas en relación a la DMO. Los pacientes con T1D presentaron niveles superiores de OC (p<0,001) y P1NP (p<0,001). Las áreas bajo la curva para la predicción de patología ósea para la OC fueron 0,732 (p=0,038) en T1D y 0,697 (p=0,007) en T2D. Se observó una relación estadísticamente significativa entre el alelo A de BsmI (p=0,03), el alelo A de ApaI (p=0,04) y el alelo C de Taql (p=0,046) y una menor DMO. Así mismo, se encontró una correlación significativa entre los niveles elevados de OC y el alelo G de BsmI (p=0,044), el alelo C de ApaI (p=0,011), el alelo T de Taql (p=0,006) y el alelo C de FokI (p=0,004).

Conclusiones

El elevado valor predictivo negativo del punto de corte de la OC indica que la OC podría ser útil a la hora de descartar el riesgo de pérdida ósea, lo que permitiría diseñar un tratamiento personalizado para prevenir dicha patología.

Osteocalcin associates with bone mineral density and VDR gene polymorphisms in type 1 and type 2 diabetes

Objectives

Bone metabolism is impaired in diabetes mellitus (DM). Our objective is to evaluate the association of bone turnover markers (BTM) and vitamin D receptor (VDR) gene polymorphisms with bone mineral density (BMD) in DM type 1 (T1D) and DM type 2 (T2D).

Methods

A total of 165 patients (53 T1D and 112 T2D) were enrolled. BMD was measured by dual-energy X-ray absorptiometry (DEXA). Plasma osteocalcin (OC), beta-CrossLaps (β-CTX) and N-amino terminal propeptide of type I collagen (P1NP) and VDR gene polymorphisms were evaluated.

Results

Participants were 53 T1D (41 years [31-48]) and 112 T2D (60 years [51-66]). BMD were not statistically different between the groups. OC (p<0.001) and P1NP levels (p<0.001) were higher in patients with T1D. The areas under the curve for the prediction of bone pathology were 0.732 (p=0.038) for OC in T1D and 0.697 (p=0.007) in T2D. A significant association was found between lower lumbar BMD and the A allele of BsmI (p=0.03), the A allele of ApaI (p=0.04) and the allele C of the Taql (p=0.046). Also, a significant correlation was found with higher OC levels and the G allele of BsmI (p=0.044), C allele of ApaI (p=0.011), T allele of Taql (p=0.006) and with C allele of FokI (p=0.004).

Conclusions

The high negative predictive value of the cut-off point for OC suggests that could be useful in excluding the risk suffering bone loss, allowing offering a personalized clinical approach to prevent this pathology.

Association of dietary carbohydrate and fiber ratio with postmenopausal bone mineral density and prevalence of osteoporosis: A cross-sectional study

BACKGROUND

This study aimed to investigate the associations of carbohydrate to dietary fiber ratio with bone mineral density (BMD) and the prevalence of osteoporosis in postmenopausal women.

METHODS

This cross-sectional study retrieved the data of 2829 postmenopausal women from the National Health and Nutrition Examination Survey (NHANES) database. Weighted univariable logistic regression models were used to investigate the correlations of carbohydrate, dietary fiber, or carbohydrate to fiber ratio with osteoporosis.

RESULTS

Higher dietary fiber intake was correlated with decreased odds ratio of osteoporosis [odds ratio(OR) = 0.96, 95% confidence interval (CI): 0.93 to 0.99]. The odds ratio of osteoporosis in postmenopausal women was elevated as the increase of carbohydrate to fiber ratio (OR = 1.80, 95%CI: 1.10 to 2.96). Carbohydrate to fiber ratio >17.09 was related to increased odds ratio of osteoporosis (OR = 1.63, 95%CI: 1.04 to 2.56). Compared to the carbohydrate to fiber ratio ≤11.59 group, carbohydrate to fiber ratio >17.09 was associated with decreased total femur BMD (β = -0.015, 95%CI: -0.028 to -0.001) and femur neck BMD (β = -0.020, 95%CI: -0.033 to -0.006) in postmenopausal women. The femur neck BMD in postmenopausal women was decreased with the increase of carbohydrate to fiber ratio (β = -0.015, 95%CI: -0.028 to -0.001).

CONCLUSION

In postmenopausal women, a high carbohydrate/fiber ratio >17.09 is associated with an increased risk of osteoporosis and lower hip BMD and high fiber intake is associated with less osteoporosis and higher hip BMD.

Effect of calcium plus Vitamin-D combined with calcitriol in the treatment of patients with Type-2 diabetes and osteoporosis: A retrospective observational analysis

Objective

To explore the clinical effect of calcium plus Vitamin-D combined with calcitriol in the treatment of patients with type-2 diabetes mellitus (T2DM) patients and osteoporosis.

Methods

In this retrospective observational study clinical records of 90 patients with T2DM combined with osteoporosis, treated in The Quzhou Affiliated Hospital of Wenzhou Medical University from October 2019 to April 2022 were incuded. All patients received basic hypoglycemic treatment. Of 90 patients, 43 received calcium plus Vitamin-D adjuvant therapy (Control-group), and 47 patients received calcium plus Vitamin-D combined with calcitriol adjuvant therapy (Observation-group). Clinical efficacy, adverse reactions, bone metabolism levels, and changes in bone density levels were compared between the two groups.

Results

The clinical efficacy of the treatment was significantly higher in the Observation-group (93.6%) compared to the Control-group (83.7%; p<0.05). There was no statistically significant difference in the incidence of adverse reactions between the two groups (p>0.05). After treatment, bone metabolism and bone density indicators in both groups improved, and were significantly better in the Observation-group compared to the Control-group (p<0.05).

Conclusions

Combination of calcium plus Vitamin-D and calcitriol adjuvant therapy in patients with T2DM and osteoporosis is safe and associated with better treatment efficacy, improved bone metabolism and bone density parameters than calcium plus Vitamin-D treatment alone.

Effects of 4-hexylresorcinol on facial skeletal development in growing rats: Considerations for diabetes

Objective

: To investigate the long-term effects of 4-hexylresorcinol (4HR) on facial skeletal growth in growing male rats, with a focus on diabetic animal models.

Methods

: Forty male rats were used. Of them, type 1 diabetes mellitus was induced in 20 animals by administering 40 mg/kg streptozotocin (STZ), and they were assigned to either the STZ or 4HR-injected group (STZ/4HR group). The remaining 20 healthy rats were divided into control and 4HR groups. We administered 4HR subcutaneously at a weekly dose of 10 mg/kg until the rats were euthanized. At 16 weeks of age, whole blood was collected, and micro-computed tomography of the skull and femur was performed.

Results

: All craniofacial linear measurements were smaller in the STZ group than in the control group. The mandibular molar width was significantly smaller in the 4HR group than in the control group (P = 0.031) but larger in the STZ/4HR group than in the STZ group (P = 0.011). Among the diabetic animals, the STZ/4HR group exhibited significantly greater cortical bone thickness, bone mineral density, and bone volume than the STZ group. Serum testosterone levels were also significantly higher in the STZ/4HR group than in the STZ group.

Conclusions

: 4HR administration may have divergent effects on mandibular growth and bone mass in healthy and diabetic rats. In the context of diabetes, 4HR appears to have beneficial effects, potentially through the modulation of mitochondrial respiration.

Causal relationship between body mass index, type 2 diabetes and bone mineral density: Mendelian randomization

OBJECTIVE

To reveal the relationship between Body Mass Index(BMI), type 2 diabetes, and bone mineral density(BMD) using a mendelian randomization (MR) approach.

METHODS

GWAS data on BMI, type 2 diabetes, and BMD were selected from the IEU GWAS database at the University of Bristol.Univariable, multivariable, and mediated MR analyses were used to explore the relationship between BMI, type 2 diabetes, and BMD. beta(β) values were given, and three methods, including inverse variance weighting, MR-Egger regression, and weighted median, were used in this analysis.

RESULTS

Univariable mendelian randomization (UVMR) results showed that BMI and type 2 diabetes were positively associated with BMD. However, the association between BMI and BMD was insignificant in the multivariable Mendelian randomization (MVMR) analysis, while that between type 2 diabetes and BMD remained significant. Mediated MR analysis indicated that type 2 diabetes mediated the regulation of BMD by BMI.

CONCLUSION

This study provides evidence supporting a positive causal association between BMI, type 2 diabetes, and BMD. Type 2 diabetes acts as a mediator in the regulation of BMD by BMI, indicating that both BMI and type 2 diabetes exert a protective influence on BMD.

The metabolic score of insulin resistance is positively correlated with bone mineral density in postmenopausal patients with type 2 diabetes mellitus

The prevalence of type 2 diabetes mellitus (T2DM) complicated with osteoporosis (OP) is increasing yearly. Early prevention, detection and treatment of OP are important in postmenopausal patients with T2DM. This study aimed to explore the correlation between insulin resistance and bone mineral density (BMD), and OP in postmenopausal patients with T2DM. In this study, postmenopausal patients with T2DM who visited our hospital from January 2021 to March 2022 were divided into the OP group (n = 91) and non-OP group (n = 119) according to whether they were complicated with OP or not. The general data of patients, BMD, blood routine, glucose metabolism, lipid metabolism, liver and kidney function indexes were collected, and the homeostatic model assessment for IR (HOMA-IR), the triglyceride-glucose (TyG) index and the metabolic score for IR (METS-IR) were calculated. A weighted multivariate linear regression model assessed the correlation between insulin resistance (IR) related indexes and lumbar spine, femoral neck, and hip BMD. A weighted logistic regression model assessed the odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association between the IR-related indexes and OP risk. The nonlinear relationship was also evaluated by smooth curve fitting (SCF) and a weighted generalized additive model (GAM). Moreover, the Receiver-operating characteristics (ROC) curve was used to analyze the predictive efficiency of METS-IR in postmenopausal patients with T2DM with OP. HOMA-IR, TyG, and METS-IR in the OP group were lower than those in the non-OP group (all P < 0.05). Weighted multiple linear regression after adjusting covariates showed that METS-IR was positively correlated with the lumbar spine, femoral neck, and hip BMD (β_METS-IR = 0.006,0.005,0.005, all P < 0.001). The results of weighted Logistic regression and GAM showed that when METS-IR < 44.5, each unit of increased METS-IR value was associated with a decreased OP risk of 12% (P = 0.002). When METS-IR ≥ 44.5, there was no significant correlation between METS-IR and the risk of OP (OR = 1.00, P = 0.934). Similar trends were not observed in HOMA-IR and TyG. The ROC suggested helpful discriminative power of the METS-IR index for T2DM. We confirmed that METS-IR, as a novel alternative marker of IR, had a positive association with BMD in postmenopausal patients with T2DM, and METS-IR was a protective factor for OP in a specific range.

Biochemical Markers of Bone Fragility in Patients with Diabetes. A Narrative Review by the IOF and the ECTS

CONTEXT

The risk of fragility fractures is increased in both type 1 and type 2 diabetes. Numerous biochemical markers reflecting bone and/or glucose metabolism have been evaluated in this context. This review summarizes current data on biochemical markers in relation to bone fragility and fracture risk in diabetes.

METHODS

Literature review by a group of experts from the International Osteoporosis Foundation (IOF) and European Calcified Tissue Society (ECTS) focusing on biochemical markers, diabetes, diabetes treatments and bone in adults.

RESULTS

Although bone resorption and bone formation markers are low and poorly predictive of fracture risk in diabetes, osteoporosis drugs seem to change bone turnover markers in diabetics similarly to non-diabetics, with similar reductions in fracture risk. Several other biochemical markers related to bone and glucose metabolism have been correlated with BMD and/or fracture risk in diabetes, including osteocyte-related markers such as sclerostin, HbA1c and advanced glycation end products (AGEs), inflammatory markers and adipokines, as well as IGF-1 and calciotropic hormones.

CONCLUSION

Several biochemical markers and hormonal levels related to bone and/or glucose metabolism have been associated with skeletal parameters in diabetes. Currently, only HbA1c levels seem to provide a reliable estimate of fracture risk, while bone turnover markers could be used to monitor the effects of anti-osteoporosis therapy.

How do carbohydrate quality indices influence on bone mass density in postmenopausal women? A case-control study

BACKGROUND

Carbohydrates are the primary energy source in Asian countries, including Iran. An emerging method can be used to measure the quality of carbohydrates, including the carbohydrate quality index (CQI), which includes a variety of components. Low-carbohydrate diet score (LCDS) has been proposed as a new method of scoring micronutrient intake that could provide a reasonable explanation for the link between diet and the risk of chronic diseases.

OBJECTIVE

This study aimed to investigate the relationship between CQI, LCDS, glycemic index (GI), glycemic load (GL), insulin load (IL), and insulin index (II) with bone mass density (BMD) in postmenopausal women.

METHOD

In this case-control study, 131 postmenopausal women with osteoporosis/osteopenia and 131 healthy postmenopausal women aged 45-65 participated. The dual-energy X-ray absorptiometry (DEXA) method measured the BMD of the lumbar vertebrae and femoral neck. A validated semi-quantitative food frequency questionnaire was used to assess dietary intake. Logistic regression were used to evaluate the relation between GI, GL, II, IL, CQI, and LCDS with BMD.

RESULTS

Diets with higher GI increased the risk of osteopenia and osteoporosis, but LCDS and CQI decreased the risk of osteopenia and osteoporosis.

CONCLUSION

These findings suggest that a higher intake of fruits and vegetables and receiving various dietary vitamins, minerals, and antioxidant compounds may be a useful way to prevent osteopenia in Iranian women.

Morphometric Changes of Osteocyte Lacunar in Diabetic Pig Mandibular Cancellous Bone

Osteocytes play an important role in bone metabolism. The interactions of osteocytes with the surrounding microenvironment can alter cellular and lacunar morphological changes. However, objective quantification of osteocyte lacunae is challenging due to their deep location in the bone matrix. This project established a novel method for the analytical study of osteocytes/lacunae, which was then used to evaluate the osteocyte morphological changes in diabetic pig mandibular bone. Eight miniature pigs were sourced, and diabetes was randomly induced in four animals using streptozotocin (STZ) administration. The mandibular tissues were collected and processed. The jawbone density was evaluated with micro-CT. Osteocyte lacunae were effectively acquired and identified using backscattered electron scanning microscopy (BSE). A significantly decreased osteocyte lacunae size was found in the diabetic group. Using the acid etching method, it was demonstrated that the area of osteocyte and lacunae, and the pericellular areas were both significantly reduced in the diabetes group. In conclusion, a standard and relatively reliable method for analyzing osteocyte/lacunae morphological changes under compromised conditions has been successfully established. This method demonstrates that diabetes can significantly decrease osteocyte/lacunae size in a pig's mandibular cancellous bone.

Organokines, Sarcopenia, and Metabolic Repercussions: The Vicious Cycle and the Interplay with Exercise

Sarcopenia is a disease that becomes more prevalent as the population ages, since it is directly linked to the process of senility, which courses with muscle atrophy and loss of muscle strength. Over time, sarcopenia is linked to obesity, being known as sarcopenic obesity, and leads to other metabolic changes. At the molecular level, organokines act on different tissues and can improve or harm sarcopenia. It all depends on their production process, which is associated with factors such as physical exercise, the aging process, and metabolic diseases. Because of the seriousness of these repercussions, the aim of this literature review is to conduct a review on the relationship between organokines, sarcopenia, diabetes, and other metabolic repercussions, as well the role of physical exercise. To build this review, PubMed-Medline, Embase, and COCHRANE databases were searched, and only studies written in English were included. It was observed that myokines, adipokines, hepatokines, and osteokines had direct impacts on the pathophysiology of sarcopenia and its metabolic repercussions. Therefore, knowing how organokines act is very important to know their impacts on age, disease prevention, and how they can be related to the prevention of muscle loss.

The association of nonalcoholic fatty liver disease with bone mineral density in type 2 diabetes

Objective

We examined the association between nonalcoholic fatty liver disease and lumbar spine bone mineral density in individuals with and without type 2 diabetes.

Methods

The lumbar BMD of 1088 subjects was measured using dual-energy X-ray absorptiometry (DXA). Liver fat content was quantified via B-mode ultrasound. Multivariable linear regression was used to study the association between NAFLD and lumbar BMD in participants with and without T2DM.

Results

The lumbar BMD in the T2DM group and the non-diabetes group was higher in the NAFLD group than in the non-NAFLD group (P < 0.001). Multivariate regression analysis in the T2DM group showed that after adjusting for confounders, the positive association between lumbar spine BMD and NAFLD remained (P = 0.027). In the non-diabetes group, after adjusting for confounders, the association between NAFLD and lumbar spine BMD disappeared.

Conclusions

The relationship between nonalcoholic fatty liver disease and lumbar bone mineral density may differ in individuals with and without diabetes. The effect of nonalcoholic fatty liver disease on bone mineral density needs to be evaluated in different clinical contexts.

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.

Contribution of diabetes to amputations in sub-Sahara Africa: A systematic review and meta-analysis

Diabetes related amputations remain a major global problem, with devastating complications. We critically appraised relevant literature to quantify the prevalence of diabetes related amputations in sub-Saharan Africa (SSA). An electronic search was performed using the EMBASE and PubMed databases until 2020. Twenty-four out of 834 studies retrieved were included. The pooled prevalence of diabetic-related amputations was 36.9% (95%CI: 32.9%-40.8%). Complications of diabetes related amputations included infection, anaemia, foot deformity and mortality. The study revealed a substantial contribution of diabetes to the burden of amputations in SSA and suggests the need for further studies to assess how to reduce the incidence of diabetes, reduce the incidence of and or delay the progression of macro and microvascular complications of diabetes in SSA.

Regenerative approaches to preserve pancreatic β-cell mass and function in diabetes pathogenesis

In both type 1 diabetes (T1D) and type 2 diabetes (T2D), there is a substantial β-cell mass loss. Residual β-cell mass is susceptible to cellular damage because of specific pancreatic β-cell characteristics. β cells have a low proliferation rate, being in human adults almost zero and a low antioxidant system that makes β cells susceptible to oxidative stress and increases their vulnerability to cell destruction. Different strategies have been addressed to preserve pancreatic β-cell residual mass and function in patients with diabetes. However, the effect of many compounds proposed in rodent models to trigger β-cell replication has different results in human β cells. In this review, scientific evidence of β-cell of two major regenerative approaches has been gathered. Regeneration proceedings for pancreatic β cells are promising and could improve β-cell proliferation capacity and contribute to the conservation of mature β-cell phenotypic characteristics. This evidence supports the notion that regenerative medicine could be a helpful strategy to yield amelioration of T1D and T2D pathogenesis.

Inflammatory potential of diet and bone mineral density in a senior Mediterranean population: a cross-sectional analysis of PREDIMED-Plus study

PURPOSE

Inflammation could play a key role in tissue damage and bone metabolism. The modified dietary inflammatory score (M-DIS) is a validated tool to estimate the inflammatory potential of the diet. In the present study, we evaluate the associations between the M-DIS and bone mineral density (BMD) in a senior Mediterranean population with overweight/obesity and metabolic syndrome.

METHODS

Baseline cross-sectional association between the M-DIS and bone mineral density was assessed in 1134 participants of the multicenter PREDIMED-Plus trial (aged 55-75 with overweight/obesity and metabolic syndrome). BMD was measured using Dual-energy X-ray Absorptiometry scans and participants answered a food frequency questionnaire to determine the M-DIS. BMD was categorized as low BMD when T score was equal or lower than -1 and normal BMD in another case. Associations between BMD and M-DIS were evaluated by using linear and logistic regressions adjusted by other co-variates.

RESULTS

Participants in the top tertile of the M-DIS had a lower BMD at total femur [β (95% CI) - 0.02 (- 0.04, - 0.01)], trochanter areas [β (95% CI) - 0.03 (- 0.05, - 0.01)] and lumbar spine area [β (95% CI) - 0.03 (- 0.07, 0.01)] (but in the last case, measures were less precise and hence not statistically significant) compared to those in the lower M-DIS tertile. Multiple logistic regression analyses showed that the odds of the total femur and femoral trochanter osteopenia/osteoporosis were higher in participants in the top tertile compared to those in the lowest tertile of M-DIS [OR (95% CI) 1.71 (1.12, 2.64), P for trend 0.015; 2.02 (1.29, 3.21), P for trend 0.002, respectively].

CONCLUSION

A high pro-inflammatory diet, measured by the M-DIS, is associated with lower BMD in a senior Mediterranean population with metabolic syndrome.

OUP accepted manuscript

Type 2 diabetes is a complex, systemic disease affected by both genetic and environmental factors. Previous research has identified genetic variants associated with type 2 diabetes risk; however, gene regulatory changes underlying progression to metabolic dysfunction are still largely unknown. We investigated RNA expression changes that occur during diabetes progression using a two-stage approach. In our discovery stage, we compared changes in gene expression using two longitudinally collected blood samples from subjects whose fasting blood glucose transitioned to a level consistent with type 2 diabetes diagnosis between the time points against those who did not with a novel analytical network approach. Our network methodology identified 17 networks, one of which was significantly associated with transition status. This 822-gene network harbors many genes novel to the type 2 diabetes literature but is also significantly enriched for genes previously associated with type 2 diabetes. In the validation stage, we queried associations of genetically determined expression with diabetes-related traits in a large biobank with linked electronic health records. We observed a significant enrichment of genes in our identified network whose genetically determined expression is associated with type 2 diabetes and other metabolic traits and validated 31 genes that are not near previously reported type 2 diabetes loci. Finally, we provide additional functional support, which suggests that the genes in this network are regulated by enhancers that operate in human pancreatic islet cells. We present an innovative and systematic approach that identified and validated key gene expression changes associated with type 2 diabetes transition status and demonstrated their translational relevance in a large clinical resource.

Correlation between urinary contents of some metals and fasting plasma glucose levels: A cross-sectional study in China

Many metals are involved in the pathogenesis of diabetes, but most of existing studies focused on single metals. The study of mixtures represents real-life exposure scenarios and deserves attention. This study aimed to explore the potential relationship of urinary copper (Cu), zinc (Zn), arsenic (As), selenium (Se), and strontium (Sr) contents with fasting plasma glucose (FPG) levels in 2766 participants. The levels of metals in urine were determined by inductively coupled plasma-mass spectrometry. We used linear regression models and the Bayesian kernel machine regression (BKMR) to evaluate the association between metals and FPG levels. In the multiple metals linear regression, Zn (β = 0.434), Se (β = 0.172), and Sr (β = -0.143) showed significant association with FPG levels (all P < 0.05). The BKMR model analysis showed that the results of single metal association were consistent with the multiple metals linear regression. The mixture of five metals had a positive over-all effect on FPG levels, and Zn (PIP = 1.000) contributed the most to the FPG levels. Cu and As were negatively correlated with FPG levels in women. The potential interaction effect between Cu and Sr was observed in participants aged ≥ 60 years old (Pinteraction = 0.035). In summary, our results suggested that multiple metals in urine are associated with FPG levels. Further studies are needed to confirm these findings and clarify the underlying mechanisms.

Comparison of insulin-like growth factor-1 and sclerostin levels between premenopausal women with and without diabetes mellitus

OBJECTIVES

This study assesses the serum levels of insulin-like growth factor-1 (IGF-1) and sclerostin as markers of decreased bone formation in premenopausal women with type 2 diabetes mellitus.

METHODS

A cross-sectional study was conducted to measure serum levels of IGF-1 and sclerostin in 40 premenopausal women with and without diabetes mellitus using an enzyme-linked immunosorbent assay. The levels of IGF-1 and sclerostin were compared between the groups using the Mann Whitney test and unpaired t-test, respectively.

RESULTS

The median IGF-1 serum levels were 40.60 ng/mL and 42.7 ng/mL in the diabetic and non-diabetic groups, respectively, with no significant difference. The serum levels of sclerostin were significantly higher in the diabetic group than in the non-diabetic group (132.1 pg/mL and 96.0 pg/mL, respectively; p < 0.001).

CONCLUSION

The levels of sclerostin were significantly higher in premenopausal women with diabetes mellitus than in the non-diabetic group. Since sclerostin influences the differentiation and maturation of osteoblasts, serum sclerostin might potentially be useful as a marker of decreased bone formation in premenopausal women with diabetes.

Characteristics of bone metabolism in postmenopausal women with newly diagnosed type 2 diabetes mellitus

OBJECTIVE

The characteristics of bone metabolism in T2DM are still controversial. This study aims to recognize bone turnover features in patients with newly diagnosed T2DM who have never been treated with anti-diabetic drugs and further explore the possible factors contributing to their impaired bone turnover.

MATERIALS AND METHODS

An analytic sample of 88 patients with newly diagnosed T2DM and 152 non-diabetic control individuals were studied. All the participants were postmenopausal women. Demographics variables and clinical history were recorded. We measured lipid profile, glucose metabolism, bone turnover markers indices as well as their related hormones, serum calcium and phosphorus. Bone mineral density was detected by dual-energy X-ray absorptiometry. We compared the differences in bone turnover markers and their regulating hormones between two groups and further analysed the factors related to bone turnover in T2DM.

RESULTS

Compared with the control group, patients with T2DM had a higher level of bone alkaline phosphatase (BALP), lower levels of procollagen type I intact N-terminal (P1NP), osteocalcin (OC) and parathyroid hormone (PTH). Multiple linear regression analysis showed that in patients with T2DM, HbA1c was negatively correlated with P1NP and OC. For patients without diabetes, HbA1c was negatively related to BALP and OC.

CONCLUSIONS

Patients with newly diagnosed T2DM may have impaired osteoblastic maturation and bone formation, which may be mainly attributed to hyperglycaemia.

Pharmaceutical Drugs and Natural Therapeutic Products for the Treatment of Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is the most widespread form of diabetes, characterized by chronic hyperglycaemia, insulin resistance, and inefficient insulin secretion and action. Primary care in T2DM is pharmacological, using drugs of several groups that include insulin sensitisers (e.g., biguanides, thiazolidinediones), insulin secretagogues (e.g., sulphonylureas, meglinides), alpha-glucosidase inhibitors, and the newest incretin-based therapies and sodium-glucose co-transporter 2 inhibitors. However, their long-term application can cause many harmful side effects, emphasising the importance of the using natural therapeutic products. Natural health substances including non-flavonoid polyphenols (e.g., resveratrol, curcumin, tannins, and lignans), flavonoids (e.g., anthocyanins, epigallocatechin gallate, quercetin, naringin, rutin, and kaempferol), plant fruits, vegetables and other products (e.g., garlic, green tea, blackcurrant, rowanberry, bilberry, strawberry, cornelian cherry, olive oil, sesame oil, and carrot) may be a safer alternative to primary pharmacological therapy. They are recommended as food supplements to prevent and/or ameliorate T2DM-related complications. In the advanced stage of T2DM, the combination therapy of synthetic agents and natural compounds with synergistic interactions makes the treatment more efficient. In this review, both pharmaceutical drugs and selected natural products, as well as combination therapies, are characterized. Mechanisms of their action and possible negative side effects are also provided.

Increasing fasting glucose and fasting insulin associated with elevated bone mineral density-evidence from cross-sectional and MR studies

We performed a cross-sectional study using the National Health Examination and Nutrition Survey (NHANES) data and a Mendelian randomisation (MR) study using the GWAS summary statistics from European populations. The T2D-related indices (fasting plasma glucose (FPG), fasting insulin (FI), and insulin resistance (IR)) were found to associate with elevated bone mineral density (BMD).

INTRODUCTION

The known associations amongst FPG, FI, IR, and BMD remain inconsistent. This study aims to explore the abovementioned associations by using cross-sectional and MR designs.

METHODS

Data from adults aged ≥ 20 years (n = 7170) in four rounds of the U.S. NHANES (2005-2010 and 2013-2014) were analysed in this cross-sectional study. Multiple linear and logistic regression models were used for statistical analyses. A two-sample MR study was performed using the genome-wide association study summary statistics obtained from the Meta-analyses of Glucose and Insulin-related traits Consortium (n = 108,557) and Genetic Factors for Osteoporosis Consortium (n = 32,735) to examine the causality of the FI-BMD association.

RESULTS

Multiple linear regression revealed that FPG was positively associated with the BMDs at the hip, femur neck, and 1st lumbar spine (L1). Multiple logistic regressions revealed that FPG levels were associated with elevated BMDs at the hip and L1, and FI and IR levels were associated with elevated BMD at the hip. Patients with type 2 diabetes had higher hip BMD than those without diabetes. In the MR study, the lumbar spine BMD increased by 0.49 g/cm² (95% confidence interval: 0.01, 0.97) in response to per unit increase in log-transformed FI.

CONCLUSION

Findings from our cross-sectional and MR studies revealed the associations between the studied diabetic indices and BMD measurements in the US and European adults.

Insulin Signaling in Arthritis

Inflammatory arthritis is burdened by an increased risk of metabolic disorders. Cytokines and other mediators in inflammatory diseases lead to insulin resistance, diabetes and hyperlipidemia. Accumulating evidence in the field of immunometabolism suggests that the cause-effect relationship between arthritis and metabolic abnormalities might be bidirectional. Indeed, the immune response can be modulated by various factors such as environmental agents, bacterial products and hormones. Insulin is produced by pancreatic cells and regulates glucose, fat metabolism and cell growth. The action of insulin is mediated through the insulin receptor (IR), localized on the cellular membrane of hepatocytes, myocytes and adipocytes but also on the surface of T cells, macrophages, and dendritic cells. In murine models, the absence of IR in T-cells coincided with reduced cytokine production, proliferation, and migration. In macrophages, defective insulin signaling resulted in enhanced glycolysis affecting the responses to pathogens. In this review, we focalize on the bidirectional cause-effect relationship between impaired insulin signaling and arthritis analyzing how insulin signaling may be involved in the aberrant immune response implicated in arthritis and how inflammatory mediators affect insulin signaling. Finally, the effect of glucose-lowering agents on arthritis was summarized.

Bee Bread Can Alleviate Lipid Abnormalities and Impaired Bone Morphology in Obese Zucker Diabetic Rats

This study examined for the first time whether bee bread (BB, consisting of monofloral rape bee pollen) could alleviate lipid derangements and reduced bone quality in Zucker diabetic fatty (ZDF) rats, which are considered an appropriate animal model for type 2 diabetes mellitus (T2DM) investigation. Adult ZDF rats were segregated into four groups: lean non-diabetic rats (L group), obese diabetic rats untreated (C group), and those treated with the BB at two doses (500 and 700 mg/kg body weight, respectively, B1 and B2 groups) for 10 weeks. Significantly reduced levels of total cholesterol and triglyceride were recorded in the B2 group versus the C group. In both BB-treated groups, significantly increased relative volume of trabecular bone and trabecular thickness, enhanced density of secondary osteons, accelerated periosteal bone apposition, and improved blood flow were observed. A positive effect of higher dose of BB on femoral weight and cortical bone thickness was also demonstrated. Our results suggest a promising potential of BB to ameliorate T2DM-related complications associated with lipid and bone damages.

Diabetes and Bone Involvement in Primary Hyperparathyroidism: Literature Review and Our Personal Experience

BACKGROUND

Primary hyperparathyroidism (PHPT) and type 2 diabetes mellitus (T2DM) are common endocrine disorders impacting on skeletal health, whose concomitant occurrence is becoming more frequent.

PATIENTS AND METHODS

We searched the PubMed database from the National Library of Medicine about the relationship between T2DM and its treatment and bone manifestations of PHPT. Thereafter, we retrospectively evaluated a consecutive series of 472 PHPT patients. Among them 55 were also affected by T2DM. At the diagnosis of PHPT we compared bone turnover markers and bone densitometry between 55 patients with and 417 without T2DM and in the former group according to antidiabetic treatment.

RESULTS

Few data are available about T2DM and PHPT bone involvement, studies about T2DM treatments and PHPT bone manifestations are lacking. Among patients with PHPT of our series, those with T2DM were older, had a lower prevalence of osteitis fibrosa cystica, higher lumbar and femoral T-scores than the remaining patients. No difference was disclosed among the diabetic patients according to ongoing antidiabetic treatment, even though modern treatments were under-represented.

CONCLUSIONS

No clinical study specifically evaluated the impact of T2DM on bone involvement in PHPT. In our experience, diabetic patients resulted more frequently "mild asymptomatic" than non-diabetic patients and showed a lower prevalence of radiological PHPT bone manifestations. The treatment of T2DM does not seem to affect the biochemical or clinical features of PHPT in our series. Further studies are needed to fully disclose the influence of T2DM and antidiabetic treatment on bone health in patients with PHPT.

Cornelian Cherry Pulp Has Beneficial Impact on Dyslipidemia and Reduced Bone Quality in Zucker Diabetic Fatty Rats

Cornelian cherry (Cornus mas L.) is a medicinal plant with a range of biological features. It is often used as a nutritional supplement in the treatment of diabetes mellitus. Our study was aimed to first investigate the effects of Cornelian cherry pulp on bone quality parameters in Zucker diabetic fatty (ZDF) rats. Moreover, lipid-lowering properties of this fruit were also evaluated. Adult rats (n = 28) were assigned into four groups of seven individuals each: L group (non-diabetic lean rats), C group (diabetic obese rats), and E1 and E2 groups (diabetic obese rats receiving 500 and 1000 mg/kg body weight of Cornelian cherry pulp, respectively, for 10 weeks). Significantly lower levels of triglyceride, total cholesterol and alkaline phosphatase activity were determined in the E2 group versus the C group. A higher dose of Cornus mas also had a beneficial impact on femoral weight, cortical bone thickness, relative volume of trabecular bone and trabecular thickness. We observed elevated density of Haversian systems and accelerated periosteal bone apposition in both treated groups (E1 and E2). Our results clearly demonstrate that Cornelian cherry pulp has a favorable effect on lipid disorder and impaired bone quality consistent with type 2 diabetes mellitus in a suitable animal model.

Fracture Risk Assessment Tool May Not Indicate Bone Fragility in Women With Type 2 Diabetes

BACKGROUND

Diabetes carries a known risk of bone fracture despite high bone mineral density (BMD). The fracture risk assessment tool (FRAX) predicts the 10-year major osteoporotic fracture risk and hip fracture risk. We investigated the effects of clinical parameters on the FRAX score and evaluated the validity of FRAX for evaluating current bone fragility in diabetes subjects.

MATERIALS AND METHODS

Forty-seven thousand, three hundred eighty-nine Japanese women participated in the Chiba bone survey, a population-based, multicenter, cross-sectional study of postmenopausal osteoporosis; we estimated FRAX scores without BMD and compared scores between subjects with and without type 2 diabetes.

RESULTS

Mean FRAX major osteoporotic fracture risk was significantly higher in the diabetes group. A multiple regression model demonstrated some clinical parameters that affected the FRAX score and, after adjusting for such parameters, the FRAX score was not significantly different between the diabetes and nondiabetes groups, although the type 2 diabetes rate was significantly higher in subjects with a fracture in the past 5 years, which reflected current bone fragility. After adjusting for clinical parameters, the diabetes rate remained significantly higher in subjects with a fracture in the past 5 years, confirming that type 2 diabetes influences current bone fragility. Our study demonstrated that type 2 diabetes truly carries a risk of bone fracture, but adjusted FRAX major osteoporotic fracture risk is not significantly different between subjects with and without type 2 diabetes.

CONCLUSIONS

The FRAX major osteoporotic fracture risk without BMD does not correctly indicate current bone fragility in Japanese middle-aged women with type 2 diabetes.

Improvement of osteogenic differentiation of human mesenchymal stem cells on composite poly l-lactic acid/nano-hydroxyapatite scaffolds for bone defect repair

Tissue engineering offers new approaches to repair bone defects, which cannot be repaired physiologically, developing scaffolds that mimic bone tissue architecture. Furthermore, biomechanical stimulation induced by bioreactor, provides biomechanical cues that regulate a wide range of cellular events especially required for cellular differentiation and function. The improvement of human mesenchymal stem cells (hMSCs) colonization in poly-l-lactic-acid (PLLA)/nano-hydroxyapatite (nHA) composite scaffold was evaluated in terms of cell proliferation (dsDNA content), bone differentiation (gene expression and protein synthesis) and ultrastructural analysis by comparing static (s3D) and dynamic (d3D) 3D culture conditions at 7 and 21 days. The colonization rate of hMSCs and osteogenic differentiation were amplified by d3D when physical stimulation was provided by a perfusion bioreactor. Increase in dsDNA content (p < 0.0005), up-regulation of RUNX2, ALPL, SPP1 (p < 0.0005) and SOX9 (p < 0.005) gene expression, and more calcium nodule formation (p < 0.0005) were observed in d3D cultures in comparison to s3D ones over time. Dynamic 3D culture, mimicking the mechanical signals of bone environment, improved significantly osteogenic differentiation of hMSCs on PLLA/nHA scaffold, without the addition of growth factors, confirming this composite scaffold suitable for bone regeneration.

Rehmannia glutinosa Libosch Extracts Prevent Bone Loss and Architectural Deterioration and Enhance Osteoblastic Bone Formation by Regulating the IGF-1/PI3K/mTOR Pathway in Streptozotocin-Induced Diabetic Rats

Rehmanniae Radix Praeparata (RR, named as Shudihuang in traditional Chinese medicine), the steamed roots of Rehmannia glutinosa Libosch (Scrophulariaceae), has been demonstrated to have anti-diabetic and anti-osteoporotic activities. This study aimed to explore the protective effect and underlying mechanism of RR on diabetes-induced bone loss. It was found that RR regulated the alkaline phosphatase activity and osteocalcin level, enhanced bone mineral density, and improved the bone microarchitecture in diabetic rats. The catalpol (CAT), acteoside (ACT), and echinacoside (ECH) from RR increased the proliferation and differentiation of osteoblastic MC3T3-E1 cells injured by high glucose and promoted the production of IGF-1 and expression of related proteins in BMP and IGF-1/PI3K/mammalian target of rapamycin complex 1 (mTOR) signaling pathways. The verifying tests of inhibitors of BMP pathway (noggin) and IGF-1/PI3K/mTOR pathway (picropodophyllin) and molecular docking of IGF-1R further indicated that CAT, ACT, and ECH extracted from RR enhanced bone formation by regulating IGF-1/PI3K/mTOR signaling pathways. These findings suggest that RR may prove to be a promising candidate drug for the prevention and treatment of diabetes-induced osteoporosis.

Glycemic control and 10-year odds of all-cause fractures in elderly veterans with type 2 diabetes

AIMS

To investigate the relationship of average level of glycemic control and fractures in elderly Veterans.

METHODS

Retrospective cohort of Veterans (age ≥65) grouped as follows: no diabetes, HbA1c ≤7.0% [≤53 mmol/mol], HbA1c 7.1-8.0% [54-64 mmol/mol], HbA1c 8.1-9.0% [65-75 mmol/mol], and HbA1c >9% [>75 mmol/mol]. Data from January 1, 2010 - January 1, 2017 from the Veteran's Affairs Corporate Data Warehouse was analyzed using Chi-square and Cox regression analysis.

RESULTS

3434 fractures occurred from the 36,744 Veterans included. The fracture incidences were 14.4, 11.7, 7.9, 8.2, and 10.8 events per 1000 patient years and the hazard ratios were 1.233 (1.130-1.345); p < 0.0001, 0.718 (0.626-0.825); p < 0.0001, 0.682 (0.545-0.854); p = 0.0009, and 0.887 (0.633-1.245); p = 0.4915 in the no diabetes, HA1c ≤7% [≤53 mmol/mol], 7.1-8% [54-64 mmol/mol], 8.1-9% [65-75 mmol/mol], and >9% [>75 mmol/mol] groups after accounting for covariates in the final model.

CONCLUSION

In elderly Veterans with type 2 diabetes the average HbA1c 7.1-8.0% [54-64 mmol/mol], and 8.1-9% [65-75 mmol/mol] have the lowest fracture incidence and those without diabetes showing the highest incidence rate; however, due to the overall low rate of fracture, the absolute difference in incidence of fracture was very small at 2-5 per 1000 patient years. Beyond limiting the risk factors identified these results don't support altering diabetes treatment goals to reduce fracture risk.

Effects of Milk and Dairy Products on the Prevention of Osteoporosis and Osteoporotic Fractures in Europeans and Non-Hispanic Whites from North America: A Systematic Review and Updated Meta-Analysis

Nutrition plays an important role in bone health. The aim of our study was to update the evidence regarding dairy intake, osteoporotic fracture (OF) risk, and prospective bone mass density (BMD) evolution assessed by dual-energy X-ray absorptiometry in Europeans and non-Hispanic whites from North America. A systematic search was conducted in MEDLINE, EMBASE, and Scopus for papers published from 1 January, 2000 to 30 April, 2018. The eligibility criteria were as follows: healthy adults; measurable dairy exposure; hip, vertebral, wrist or OF as outcomes; and cohort or case-control studies. Two independent investigators conducted the search and the data extraction. A pooled analysis was conducted with random-effects models. Publication bias and meta-regression were considered. Ten cohort studies relating to OF risk were selected for meta-analysis. Three papers reporting BMD changes associated with dairy intake could not be aggregated in the meta-analysis. The pooled HRs of the highest compared with the lowest levels of dairy intake were 0.95 (95% CI: 0.87, 1.03; I2 = 82.9%; P-heterogeneity < 0.001) for OF at any site; 0.87 (95% CI: 0.75, 1.01; I2 = 86.7%; P-heterogeneity < 0.001) for hip fractures; and 0.82 (95% CI: 0.68, 0.99; I2 = 0.0%; P-heterogeneity = 0.512) for vertebral fractures. Concerning BMD, the selected studies described a 1.7-3% lower hip BMD in young and postmenopausal women with poor intake of milk in their youth, a positive relationship between baseline milk ingestion and the percentage of trochanter BMD change in elderly people, and a positive correlation between milk consumption and BMD change at the radius in women aged >65 y. In conclusion, in the studied population, the highest consumption of dairy products did not show a clear association with the total OF or hip fracture risks; however, a diminished risk of vertebral fracture could be described. The results regarding BMD change were heterogeneous and did not allow for a definitive conclusion.

Relationship between Body Mass Index and T-Scores of Bone Mineral Density in the Hip and Spine Regions among Older Adults with Diabetes: A Retrospective Review

Diabetes mellitus (DM) cases are increasing worldwide, especially in Saudi Arabia. Previous studies suggested a positive relationship between body mass index (BMI) and bone mineral density (BMD) levels. Generally, patients with low BMI (<18.5 kg/m2) have reduced BMD levels and, thus, low T-scores; hence, they are categorized as osteopenic or osteoporotic. In this study, we aimed to determine whether a relationship between BMI and BMD T-scores in the hip and spine regions of patients with diabetes exists. This retrospective record review investigated older adult patients with diabetes in King Abdulaziz University Hospital (n=198; age 50-90 years) who underwent BMD scan between January 1, 2016, and June 25, 2018, regardless of their sex but limited to type 2 DM. The height and weight of all subjects were recorded, and BMI was calculated and categorized. We used SPSS version 21 for data analysis; measures of central tendencies, Pearson's correlations, chi-square tests, and independent t-tests were employed. We found positive relationships between BMI and BMD T-scores in the hip and spine regions (right femoral neck: R=+0.214, P ≤ 0.002; total right hip: R=+0.912, P ≤ 0.001; left femoral neck: R=+0.939, P ≤ 0.001; total left hip: R=+0.885, P ≤ 0.001; and total lumbar region: R=+0.607, P ≤ 0.001). Low BMI (<18.5 kg/m2) could be a risk factor for osteoporosis, whereas normal/high BMI could be protective against osteoporosis among adults with diabetes.

Insulin use and fracture risk in patients with type 2 diabetes: A meta-analysis of 138,690 patients

Patients with type 2 diabetes mellitus (T2DM) have been reported to have an enhanced risk of bone fracture, however the association between insulin treatment and risk of fracture in patients with T2DM remains to be fully elucidated. The aim of the present meta-analysis was to examine the possible association between insulin treatment and risk of fracture in patients with T2DM. Relevant studies published prior to and including April 2018 were identified by literature searches in PubMed, Embase and Cochrane Library databases. A meta-analysis was performed, which included relevant trials of patients with T2DM comparing insulin to oral anti-diabetic drugs. The combined effect was expressed as a pooled risk ratio (RR) with 95% confidence interval (CI), using a random-effects model. Subgroup analysis was performed to consolidate the results. A total of 7 studies comprising 138,690 patients were eligible for inclusion in the present meta-analysis. After exclusion of one study that introduced major heterogeneity, treatment with, insulin was associated with a significantly increased risk of fracture among patients with T2DM (RR=1.24, 95% CI, 1.07–1.44; P=0.004). Subgroup analysis by sex indicated that the RR for men was 1.04 (95% CI, 0.76–1.44, P=0.801) and that for women was 1.22 (95% CI, 0.92–1.62, P=0.175). Subgroup analysis by fracture site indicated that the RR for hip was 1.18 (95% CI, 0.83–1.68, P=0.363), that for vertebrae was 1.28 (95% CI, 0.90–1.81, P=0.169) and that for non-vertebrae was 1.06 (95% CI, 0.80–1.41, P=0.686). Subgroup analysis by study design suggested that the RR for prospective and retrospective studies was 1.35 (95% CI, 1.06–1.71, P=0.014) and 1.16 (95% CI, 0.99–1.35, P=0.059), respectively. Subgroup analysis by region indicated that the RR for Europe was 1.16 (95% CI, 0.91–1.48, P=0.220), that for North America was 1.24 (95% CI, 0.81–1.90, P=0.333) and that for Asia was 1.34 (95% CI, 0.91–1.98, P=0.141). In conclusion, treatment with insulin increased the risk of fractures among patients with T2DM compared with oral anti-diabetic drugs; however, the association was influenced by various factors, including sex, fracture site, study design and geographical region.

Increased frequency of impaired fasting glucose and isolated systolic hypertension in Paget's disease of bone

PURPOSE

Scanty data about glucose metabolism and hypertension have been reported in Paget's disease of bone (PDB) to be related with increased cardiovascular mortality. The aim of the present study was to evaluate glucose and blood pressure levels in PDB, looking for their association with disease severity.

METHODS

We performed an observational cross-sectional study in 54 patients with PDB and 54 age, sex and BMI-matched controls. Glucose and blood pressure levels and parameters of bone and mineral metabolism were assessed.

RESULTS

Patients with PDB showed increased glucose levels (6.3 ± 1.7 vs 5.3 ± 1.4 mmol/l, p < 0.001) and prevalence of impaired fasting glucose (14.8%, 5.3-24.3 vs 1.9%, 0-5.4, p < 0.02) as well as enhanced systolic blood pressure (145.9 ± 21.3 vs 132.9 ± 18.9 mmHg, p < 0.005), pulse pressure (69.6 ± 20.0 vs 56.0 ± 16.9 mmHg, p < 0.01) and prevalence of isolated systolic hypertension (46.3%, 33.0-59.6 vs 16.7%, 6.7-26.6, p < 0.003) in comparison to controls. Moreover, we found a positive association of (1) glucose levels with ionized calcium and bone alkaline phosphatase; (2) both systolic and pulse pressure with total and bone alkaline phosphatase (p < 0.05). By multiple linear regression analysis (R² = 0.26; p < 0.05) serum ionized calcium correlated with glucose levels (β = 0.44; p < 0.04), after adjusting for age and BMI.

CONCLUSIONS

Our study shows increased fasting glucose, systolic and pulse pressure levels as well as enhanced prevalence of impaired fasting glucose and isolated systolic hypertension in PDB, potentially accounting for increased cardiovascular mortality. Furthermore, our findings suggest high serum calcium and/or increased bone alkaline phosphatase as a link between PDB and cardio-metabolic disorders.

Higher dietary glycemic index and glycemic load values increase the risk of osteoporotic fracture in the PREvención con DIeta MEDiterránea (PREDIMED)-Reus trial

Background

High glucose and insulin concentrations seem to have a negative impact on bone health. However, the relation between the dietary glycemic index (DGI) and the dietary glycemic load (DGL), which has proved to be effective at modulating blood glucose concentrations after carbohydrate consumption, has yet to be explored in relation to bone health.

Objective

The aim of the study was to examine the associations between the DGI or DGL and the risk of osteoporotic-related fractures in an elderly Mediterranean population.

Design

The study was conducted in 870 subjects aged 55-80 y at high cardiovascular disease risk participating in the PREvención con DIeta MEDiterránea (PREDIMED)-Reus study. The DGI and DGL were estimated from validated food-frequency questionnaires with the use of the international glycemic index and glycemic load values, with glucose as reference. Data on osteoporotic fractures were acquired from a systematic review of medical records. We used Cox proportional hazard models to assess the risk of osteoporotic fracture according to tertiles of average DGI and DGL.

Results

A total of 114 new cases of osteoporotic-related fractures were documented after a mean follow-up of 8.9 y. Participants in the highest tertile of DGI and DGL had a significantly higher risk of osteoporotic fractures than those in the lowest tertile after adjusting for potential confounders (HR: 1.80; 95% CI: 1.03, 3.15 and HR: 3.20; 95% CI: 1.25, 8.18, respectively).

Conclusions

A high DGI and DGL are associated with a higher risk of osteoporosis-related fractures in an elderly Mediterranean population at high cardiovascular disease risk. This trial was registered at isrctn.com as ISRCTN35739639.

Role of nutritional vitamin D in osteoporosis treatment

Osteoporosis is a systemic skeletal disorder characterized by a decrease in bone mass and microarchitectural deterioration of bone tissue. The World Health Organization has defined osteoporosis as a decrease in bone mass (50%) and bony quality (50%). Vitamin D, a steroid hormone, is crucial for skeletal health and in mineral metabolism. Its direct action on osteoblasts and osteoclasts and interaction with nonskeletal tissues help in maintaining a balance between bone turnover and bone growth. Vitamin D affects the activity of osteoblasts, osteoclasts, and osteocytes, suggesting that it affects bone formation, bone resorption, and bone quality. At physiological concentrations, active vitamin D maintains a normal rate of bone resorption and formation through the RANKL/OPG signal. However, active vitamin D at pharmacological concentration inhibits bone resorption at a higher rate than that of bone formation, which influences the bone quality and quantity. Nutritional vitamin D rather than active vitamin D activates osteoblasts and maintains serum 25(OH)D₃ concentration. Despite many unanswered questions, much data support nutritional vitamin D use in osteoporosis patients. This article emphasizes the role of nutritional vitamin D replacement in different turnover status (high or low bone turnover disorders) of osteoporosis together with either anti-resorptive (Bisphosphonate, Denosumab et.) or anabolic (Teriparatide) agents when osteoporosis persists.

The effect of insulin on bone mineral density among women with type 2 diabetes: a SWAN Pharmacoepidemiology study

This was a longitudinal study examining the effects of insulin use on bone mineral density loss. Insulin use was found to be associated with greater bone mineral density loss at the femoral neck among women with diabetes mellitus.

INTRODUCTION

Women with diabetes mellitus (DM) have higher bone mineral density (BMD) and experience slower BMD loss but have an increased risk of fracture. The data regarding the effect of insulin treatment on BMD remains conflicted. We examined the impact of insulin initiation on BMD.

METHODS

We investigated the annual changes in BMD associated with the new use of insulin among women with DM in the Study of Women's Health Across the Nation (SWAN). Propensity score (PS) matching, which is a statistical method that helps balance the baseline characteristics of women who did and did not initiate insulin, was used. Covariates with a potential impact on bone health were included in all models. Mixed model regression was used to test the change in BMD between the two groups. Median follow-up time was 5.4 years.

RESULTS

The cohort consisted of 110 women, mean age, 53.6 years; 49% white and 51% black. Women using insulin (n = 55) were similar on most relevant characteristics to the 55 not using insulin. Median diabetes duration for the user group was 10 vs. 5.0 years for the non-user group. There was a greater loss of BMD at the femoral neck among insulin users (- 1.1%) vs non-users (- 0.77%) (p = 0.04). There were no differences in BMD loss at the spine - 0.30% vs - 0.32% (p = 0.85) or at the total hip - 0.31% vs - 0.25 (p = 0.71), respectively.

CONCLUSIONS

Women with T2DM who initiated insulin experienced a more rapid BMD loss at the femoral neck as compared to women who did use insulin.

1α,25-Dihydroxyvitamin D3 promotes bone formation by promoting nuclear exclusion of the FoxO1 transcription factor in diabetic mice

1α,25-Dihydroxyvitamin D3 (1,25(OH)2D3) is the active form of vitamin D, which is responsible for reducing the risk for diabetes mellitus (DM), decreasing insulin resistance, and improving insulin secretion. Previous studies have shown that 1,25(OH)2D3 inhibited the activity of FoxO1, which has been implicated in the regulation of glucose metabolism. However, its function and mechanism of action in DM-induced energy disorders and also in bone development remains unclear. Here, using in vitro and in vivo approaches including osteoblast-specific, conditional FoxO1-knock-out mice, we demonstrate that 1,25(OH)2D3 ameliorates abnormal osteoblast proliferation in DM-induced oxidative stress conditions and rescues the impaired glucose and bone metabolism through FoxO1 nuclear exclusion resulting from the activation of PI3K/Akt signaling. Using alizarin red staining, alkaline phosphatase assay, Western blot, and real-time qPCR techniques, we found that 1,25(OH)2D3 promotes osteoblast differentiation and expression of osteogenic phenotypic markers (i.e. alkaline phosphatase (1), collagen 1 (COL-1), osteocalcin (OCN), and osteopontin (OPN)) in a high-glucose environment. Moreover, 1,25(OH)2D3 increased both total OCN secretion and levels of uncarboxylated OCN (GluOC) by phosphorylating FoxO1 and promoting its nuclear exclusion, indicated by Western blot and cell immunofluorescence analyses. Taken together, our findings confirm that FoxO1 is a key mediator involved in glucose homeostasis and indicate that 1,25(OH)2D3 improves glucose metabolism and bone development via regulation of PI3K/Akt/FoxO1/OCN pathway.

Clinical utility of serum 25-hydroxyvitamin D in the diagnosis of insulin resistance and estimation of optimal 25-hydroxyvitamin D in U.S. adults

AIMS

To assess the clinical utility of measuring serum 25-hydroxyvitamin-D [25(OH)D] along with traditional risk factors in the diagnosis of insulin resistance (IR) and to estimate the optimal 25(OH)D level associated with normal glucose and insulin homeostasis.

METHODS

A cross-sectional analysis of 6868 adults aged≥20years without diagnosed diabetes in the National Health and Nutrition Examination Survey, with available standardized 25(OH)D data (2001-2010). IR was defined by the homeostatic-model-assessment of insulin resistance (HOMA-IR; ≥75th percentile, sex-specific: 3.9 in men or 3.6 in women). Using logistic regression, two risk models were developed to estimate the risk of IR: Model 1 included established risk factors, and Model 2 additionally included serum 25(OH)D. Predictiveness curves and decision-curve analysis were used to assess differences in IR detection among models. Receiver-operating-characteristic curves were used to estimate the lower threshold for 25(OH)D. Results were validated in a testing sample.

RESULTS

Model 2 marginally improved detection of IR: at a risk threshold of 0.2, adding 25(OH)D would identify an additional 2 to 4 cases per 1000 people. Overall, the lower 25(OH)D threshold was estimated at 60nmol/L, however, the threshold differed by ethnicity (Mexican-Americans: 54nmo/L, non-Hispanic whites: 68nmol/L, and non-Hispanic blacks: 41nmol/L).

CONCLUSION

Addition of serum 25(OH)D to traditional risk factors provided small incremental improvement in detection of IR in asymptomatic adults. The optimal 25(OH)D threshold was estimated to be at least 60nmol/L, however, the threshold may differ by ethnic-background. Further research is needed to validate these results in other populations.

1α,25-Dihydroxyvitamin D3 promotes osteogenesis by promoting Wnt signaling pathway

Diabetes mellitus (DM) remarkably affects bone metabolism and causes multiple skeletal disorders, which are associated with the increased oxidative stress that activates Forkhead family of transcription factors (FoxOs). 1α,25-Dihydroxy vitamin D₃ (1,25(OH)₂D₃), the hormonally active form of vitamin D, plays a potential role in the prevention of glucose tolerance. However, its mechanism of action in high glucose-induced energy disorders remains unclear. In vitro study shows that 1,25(OH)₂D₃ promotes osteogenesis in high glucose-induced oxidative stress mainly results from increased osteoblasts proliferation and decreased apoptosis. Cells treated with 1,25(OH)₂D₃ exhibit an increased osteogenic differentiation capacity and an elevated level of osteogenic phenotype (i.e. alkaline phosphatase, collagen 1, osteocalcin, and osteopontin). We also found that the effect of 1,25(OH)₂D₃ on osteogenesis is achieved by FoxO1 inactivation and nuclear exclusion through PI3K/Akt pathway in a time- and dose-dependent manner. Moreover, the diversion of β-catenin from FoxO1- to Wnt/TCF4-mediated transcription was indirectly promoted by the inactivation of FoxO1. These data together reveals that the activated Wnt/β-catenin signaling is involved in the regulatory action of 1,25(OH)₂D₃ on osteogenesis in oxidative stress. This study also provides a novel understanding of the effect of 1,25(OH)₂D₃ on skeleton in oxidative stress condition.

Fructus Ligustri Lucidi in Osteoporosis: A Review of its Pharmacology, Phytochemistry, Pharmacokinetics and Safety

Background: Fructus Ligustri Lucidi (FLL) has now attracted increasing attention as an alternative medicine in the prevention and treatment of osteoporosis. This study aimed to provide a general review of traditional interpretation of the actions of FLL in osteoporosis, main phytochemical constituents, pharmacokinetics, pharmacology in bone improving effect, and safety. Materials and Methods: Several databases, including PubMed, China National Knowledge Infrastructure, National Science and Technology Library, China Science and Technology Journal Database, and Web of Science were consulted to locate publications pertaining to FLL. The initial inquiry was conducted for the presence of the following keywords combinations in the abstracts: Fructus Ligustri Lucidi, osteoporosis, phytochemistry, pharmacokinetics, pharmacology, osteoblasts, osteoclasts, salidroside. About 150 research papers and reviews were consulted. Results: FLL is assumed to exhibit anti-osteoporotic effects by improving liver and kidney deficiencies and reducing lower back soreness in Traditional Chinese Medicine (TCM). The data from animal and cell experiments demonstrate that FLL is able to improve bone metabolism and bone quality in ovariectomized, growing, aged and diabetic rats through the regulation of PTH/FGF-23/1,25-(OH)₂D₃/CaSR, Nox4/ROS/NF-κB, and OPG/RANKL/cathepsin K signaling pathways. More than 100 individual compounds have been isolated from this plant. Oleanolic acid, ursolic acid, salidroside, and nuzhenide have been reported to exhibit the anti-osteoporosis effect. The pharmacokinetics data reveals that salidroside is one of the active constituents, and that tyrosol is hard to detect under physiological conditions. Acute and subacute toxicity studies show that FLL is well tolerated and presents no safety concerns. Conclusions: FLL provides a new option for the prevention and treatment of osteoporosis, which attracts rising interests in identifying potential anti-osteoporotic compounds and fractions from this plant. Further scientific evidences are expected from well-designed clinical trials on its bone protective effects and safety.