Prevalence and predictors of osteopenia and osteoporosis in adults with Type 1 diabetes

Bone Mineral Density in Adult Patients with Type 1 Diabetes Mellitus Assessed by Both DXA and QCT

Purpose

Bone mineral density (BMD) was measured in uncomplicated young adult patients with type 1 diabetes mellitus (T1DM) and sex- and age-matched controls, using both dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) to investigate their diagnostic ability in detecting abnormal values in these patients.

Methods

118 patients with T1DM (65 females, mean age 30.12 ± 8.78 years) and 94 sex- and age-matched controls were studied. BMD was assessed in all participants by DXA and QCT at lumbar spine (LS). Biochemical markers of bone metabolism were also measured.

Results

T1DM was associated with lower BMD at L1-L3 vertebrae measured by both DXA and QCT and lower bone turnover compared to sex- and age-matched controls. In T1DM subjects, QCT detected more patients with abnormal BMD values compared to DXA. BMI and HbA1c levels were the only determinants of BMD. Bone turnover markers were lower in patients with longer duration of diabetes.

Conclusion

QCT provides a higher sensitivity compared to DXA in detecting abnormal BMD values in patients with uncomplicated T1DM. In these patients, the diabetes-related decreased BMD may be present early, before it is detected by DXA, the clinical gold standard for BMD measurements, and before the presence of any other diabetes complications, stressing the importance of an early intervention for fracture prevention.

Bone mineral density progression following long-term simultaneous pancreas-kidney transplantation in type-1 diabetes

INTRODUCTION

Simultaneous pancreas-kidney transplantation (SPKT) has demonstrated favorable impact on the progression of chronic complications in type-1 diabetes (T1D) and terminal chronic kidney disease (CKD). However, some CKD mineral and bone disorders (CKD-MBD) may persist, even after transplantation. There are only a few studies addressing the long-term progression of bone mineral density (BMD) in these patients. Our aim was to assess baseline BMD and long-term progression and consequences in patients with T1D undergoing SPKT.

METHODS

A retrospective cohort included patients undergoing SPKT in our tertiary center between 2000 and 2017. BMD progression was assessed on dual X-ray absorptiometry (DXA). Only patients with baseline data and a minimum follow-up of 2 years were included.

RESULTS

Seventy-three patients were included, 53.4% male, with a median age at SPKT of 35 years (interquartile range [IQR] 31; 39). At transplantation, the median T-scores for the lumbar spine (LS) and femoral neck (FN) were -1.6 (IQR -2.6; -1.1) and --2.1 (IQR -2.7; -1.6), respectively. Seventy-five percent of patients presented low BMD (osteopenia or osteoporosis) in the LS and 90% in the FN, with 33% osteoporosis in the LS and 36% in the FN. On multivariate analysis, male gender (odds ratio [OR] 10.82, 95% confidence interval (CI) 2.88-40.70) and low body-mass index (BMI) (OR 0.73, 95% CI 0.55-0.97) were significantly associated with lumbar but not femoral osteoporosis. At long-term follow-up, BMD significantly improved in the LS (ΔT-score +0.41, P<0.001) and FN (ΔT-score +0.29, P=0.01), at a median 4 years after SPKT. Twelve (16.4%) and 9 (12.3%) patients showed persistent FN and LS osteoporosis, respectively. Multivariate linear regression showed that high BMI was predictive of improvement in BMD.

CONCLUSIONS

This study demonstrated severe skeletal fragility in T1D patients with terminal CKD undergoing SPKT, more than a quarter of whom showed osteoporosis. The significant improvement in BMD may result from metabolic correction by SPKT and from physiological skeleton mineralization, which continues in this age group. BMD progression was positively associated with BMI, due to improved nutritional balance after transplantation.

Role of nitric oxide in type 1 diabetes-induced osteoporosis

Type 1 diabetes (T1D)-induced osteoporosis is characterized by decreased bone mineral density, bone quality, rate of bone healing, bone formation, and increased bone resorption. Patients with T1D have a 2-7-fold higher risk of osteoporotic fracture. The mechanisms leading to increased risk of osteoporotic fracture in T1D include insulin deficiency, hyperglycemia, insulin resistance, lower insulin-like growth factor-1, hyperglycemia-induced oxidative stress, and inflammation. In addition, a higher probability of falling, kidney dysfunction, weakened vision, and neuropathy indirectly increase the risk of osteoporotic fracture in T1D patients. Decreased nitric oxide (NO) bioavailability contributes to the pathophysiology of T1D-induced osteoporotic fracture. This review discusses the role of NO in osteoblast-mediated bone formation and osteoclast-mediated bone resorption in T1D. In addition, the mechanisms involved in reduced NO bioavailability and activity in type 1 diabetic bones as well as NO-based therapy for T1D-induced osteoporosis are summarized. Available data indicates that lower NO bioavailability in diabetic bones is due to disruption of phosphatidylinositol 3‑kinase/protein kinase B/endothelial NO synthases and NO/cyclic guanosine monophosphate/protein kinase G signaling pathways. Thus, NO bioavailability may be boosted directly or indirectly by NO donors. As NO donors with NO-like effects in the bone, inorganic nitrate and nitrite can potentially be used as novel therapeutic agents for T1D-induced osteoporosis. Inorganic nitrites and nitrates can decrease the risk for osteoporotic fracture probably directly by decreasing osteoclast activity, decreasing fat accumulation in the marrow cavity, increasing osteoblast activity, and increasing bone perfusion or indirectly, by improving hyperglycemia, insulin resistance, and reducing body weight.

Lower bone mineral density and higher bone resorption marker levels in premenopausal women with type 1 diabetes in Japan

AIMS/INTRODUCTION

Type 1 diabetes is associated with poorer bone quality. Quantitative ultrasound provides an estimate of bone mineral density (BMD) and can also be used to evaluate bone quality, which is associated with an increased fracture risk in people with type 1 diabetes. The aim of this study was to evaluate the association between menopausal status and a bone turnover marker with heel BMD using quantitative ultrasound in women with type 1 diabetes and age- and body mass index-matched controls.

MATERIALS AND METHODS

A total of 124 individuals recruited in Kyoto and Osaka, Japan - 62 women with type 1 diabetes (mean age 47.2 ± 17.3 years) and 62 age-, menopausal status-, sex- and body mass index-matched non-diabetic control individuals (mean age 47.3 ± 16.3 years) - were enrolled in this study. Heel BMD in the calcaneus was evaluated using ultrasonography (AOS-100NW, Hitachi-Aloka Medical, Ltd., Tokyo, Japan). A bone turnover marker was also measured.

RESULTS

The heel BMD Z-score was significantly lower in premenopausal women with type 1 diabetes than in the premenopausal control group, but not in postmenopausal women with type 1 diabetes. Levels of tartrate-resistant acid phosphatase-5b, a bone resorption marker, were significantly higher in premenopausal women with type 1 diabetes than in the premenopausal control group, but not in postmenopausal women with type 1 diabetes. The whole parathyroid hormone level was significantly lower in both pre- and postmenopausal women with type 1 diabetes.

CONCLUSIONS

Lower heel BMD, higher tartrate-resistant acid phosphatase-5b level and lower parathyroid hormone were observed in premenopausal women with type 1 diabetes. Premenopausal women with type 1 diabetes require osteoporosis precautions for postmenopause.

Comparing the bone mineral density among male patients with latent autoimmune diabetes and classical type 1 and type 2 diabetes, and exploring risk factors for osteoporosis

AIMS

This study aimed to compare the bone mineral densities (BMDs) among male patients with latent autoimmune diabetes in adults (LADA), classical type 1 diabetes (T1DM), and type 2 diabetes (T2DM), and to examine the risk factors for developing low BMD in these patients.

PATIENTS AND METHODS

Between January 2017 and October 2020, a total of 57, 67, and 223 male patients with LADA, classical T1DM, and T2DM, respectively, were recruited from the endocrinology department of Shanghai Tenth People's Hospital. Hormonal markers of bone metabolism, lipid profiles, uric acid, glycosylated hemoglobin A1c (HbA1c), and beta-cell function were measured using blood samples. BMD was measured at the lumbar spine, femoral neck, and right hip by dual-energy X-ray absorptiometry.

RESULTS

The mean BMD values from all three skeletal sites in male patients with LADA were comparable to those with classical T1DM but were much lower than those with T2DM. After adjusting for confounding factors, multiple linear regression analysis demonstrated that in all male patients with diabetes, body mass index (BMI), uric acid, and fasting C-peptide showed significant positive associations with BMD at all three skeletal sites; however, osteocalcin showed a negative association at all three sites.

CONCLUSIONS

Compared with male patients with T2DM, lower BMDs were observed in patients with LADA and T1DM. Low BMI, uric acid, C-peptide levels, and high osteocalcin levels are risk factors for developing low BMD in male patients with diabetes.

Bone Mineral Density and Type 1 Diabetes in Children and Adolescents: A Meta-analysis

BACKGROUND

There is substantial evidence that adults with type 1 diabetes have reduced bone mineral density (BMD); however, findings in youth are inconsistent.

PURPOSE

To perform a systematic review and meta-analysis of BMD in youth with type 1 diabetes using multiple modalities: DXA, peripheral quantitative computed tomography (pQCT), and/or quantitative ultrasound (QUS).

DATA SOURCES

PubMed, Embase, Scopus, and Web of Science from 1 January 1990 to 31 December 2020, limited to humans, without language restriction.

STUDY SELECTION

Inclusion criteria were as follows: cross-sectional or cohort studies that included BMD measured by DXA, pQCT, or QUS in youth (aged <20 years) with type 1 diabetes and matched control subjects.

DATA EXTRACTION

We collected data for total body, lumbar spine, and femoral BMD (DXA); tibia, radius, and lumbar spine (pQCT); and phalanx and calcaneum (QUS). Weighted mean difference (WMD) or standardized mean difference was estimated and meta-regression was performed with age, diabetes duration, and HbA1c as covariates.

DATA SYNTHESIS

We identified 1,300 nonduplicate studies; 46 met the inclusion criteria, including 2,617 case and 3,851 control subjects. Mean ± SD age was 12.6 ± 2.3 years. Youth with type 1 diabetes had lower BMD: total body (WMD -0.04 g/cm2, 95% CI -0.06 to -0.02; P = 0.0006), lumbar spine (-0.02 g/cm2, -0.03 to -0.0; P = 0.01), femur (-0.04 g/cm2, -0.05 to -0.03; P < 0.00001), tibial trabecular (-11.32 g/cm3, -17.33 to -5.30; P = 0.0002), radial trabecular (-0.91 g/cm3, -1.55 to -0.27; P = 0.005); phalangeal (-0.32 g/cm3, -0.38 to -0.25; P < 0.00001), and calcaneal (standardized mean difference -0.69 g/cm3, -1.11 to -0.26; P = 0.001). With use of meta-regression, total body BMD was associated with older age (coefficient -0.0063, -0.0095 to -0.0031; P = 0.002) but not with longer diabetes duration or HbA1c.

LIMITATIONS

Meta-analysis was limited by the small number of studies with use of QUS and pQCT and by lack of use of BMD z scores in all studies.

CONCLUSIONS

Bone development is abnormal in youth with type 1 diabetes, assessed by multiple modalities. Routine assessment of BMD should be considered in all youth with type 1 diabetes.

Diabetes and Osteoporosis: Part I, Epidemiology and Pathophysiology

Both diabetes and osteoporosis are increasingly prevalent diseases, in part owing to aging populations worldwide. Epidemiologic data have shown that other organs may be adversely affected by diabetes, including the skeleton, in what has become known as diabetes-induced osteoporosis, which represents the combined impact of conventional osteoporosis with the additional fracture burden attributed to diabetes. There is an increased risk of fracture in patients with Type 1 and Type 2 diabetes, and some antidiabetic medications also may contribute to increased risk of fracture in diabetes.

Incidence of fractures in patients with type 1 diabetes mellitus-a retrospective study with 4420 patients

This retrospective study investigated the incidence of fracture in 4420 type 1 diabetes (T1DM) patients. Our findings indicate that patients with T1DM have an increased incidence of fractures. Further studies and preventive measures are urgently needed.

INTRODUCTION

The aim of this study was to investigate the incidence of fracture in patients with type 1 diabetes mellitus (T1DM).

METHODS

This study is based on the German Disease Analyzer database and included 4258 adult individuals with a T1DM diagnosis documented between January 2000 and December 2015 in 1203 general practices in Germany. Individual matching of T1DM and non-diabetic patients was performed. The cumulative incidence of new fractures was shown for up to 10 years after the index date using Kaplan-Meier curves. Cox proportional hazard models (dependent variable: incident fracture) were used to estimate the effect of T1DM on fracture incidence, as well as the effect of predefined variables on fracture incidence.

RESULTS

After 10 years of follow-up, the cumulative fracture incidence was 18.4% for T1DM patients and 9.9% for non-diabetic patients (p < 0.001). A strong association between T1DM and fractures was found (HR, 2.01 (95% CI, 1.70-2.38) p < 0.001) in both female and male patients. Significant differences between T1DM and non-diabetes patients were found in lower leg/ankle, foot and toe, shoulder/upper arm, and rib(s), sternum and thoracic spine fractures. A significant association between higher age and fracture incidence was observed in T1DM patients.

CONCLUSIONS

In summary, we found that patients with T1DM have a twofold increased fracture rate compared with healthy controls. Furthermore, fractures were associated with increased age and high HbA1c values.

Diabetes Mellitus and Osteoporosis Correlation: Challenges and Hopes

Diabetes and osteoporosis are two common diseases with different complications. Despite different therapeutic strategies, managing these diseases and reducing their burden have not been satisfactory, especially when they appear one after the other. In this review, we aimed to clarify the similarity, common etiology and possible common adjunctive therapies of these two major diseases and designate the known molecular pattern observed in them. Based on different experimental findings, we want to illuminate that interestingly similar pathways lead to diabetes and osteoporosis. Meanwhile, there are a few drugs involved in the treatment of both diseases, which most of the time act in the same line but sometimes with opposing results. Considering the correlation between diabetes and osteoporosis, more efficient management of both diseases, in conditions of concomitant incidence or cause and effect condition, is required.

Retrospective Analysis of Bone Metabolism in Patients on Waiting List for Simultaneous Pancreas-Kidney Transplantation

Posttransplant osteoporosis, which evolves from preexisting bone pathologies, represents a serious complication with deteriorating consequences. The aim of our study was to evaluate epidemiological data on bone mineral density (BMD) in subjects with type 1 diabetes (T1DM) in advanced stages of diabetic nephropathy indicated for simultaneous pancreas-kidney transplantation (SPK). We retrospectively compiled biochemical and densitometrical data from 177 patients with T1DM at CKD (chronic kidney disease) stages G4-G5 (115 men, 62 women, median age 40 yr, diabetes duration 23 yr) enrolled on waiting list for SPK for the first time between the years 2011 and 2016. Median Z-scores were as follows: lumbar spine (LS): -0.8 [interquartile range -1.75 to 0.1]; total hip (TH): -1.2 [-1.75 to -0.6]; femoral neck (FN): -1.2 [-1.9 to -0.7]; and distal radius (DR): -0.8 [-1.4 to -0.1]. We noted a gender difference in LS, with worse results for men (-1.1 vs. -0.3) even after adjusting for BMI (body mass index) and glomerular filtration (p < 0.001). Osteoporotic and osteopenic ranges (based on T-scores) for all major sites were 27.7% and 56.5%, respectively, with similar results across both genders. Women had a significantly higher proportion of normal BMD in LS than men (67.7 vs. 49.4%, p < 0.05). Patients with T1DM at CKD stages G4-G5 exhibited serious BMD impairment despite their young age. Men surprisingly displayed lower Z-scores and higher percentages of pathological BMD values in LS than women did. The introduction of adequate preventive measures during the advanced stages of diabetic nephropathy to prevent bone loss is recommended.

Determinants of fracture in adults with type 1 diabetes in the USA: Results from the T1D Exchange Clinic Registry

AIMS

To examine the prevalence/determinants of fracture in the T1D Exchange Clinic Registry.

RESEARCH DESIGN/METHODS

Adults (≥18 years) with T1D duration ≥5 years, diagnosed before age 45 years completed a fracture questionnaire. Additional characteristics were collected from registry data. Only fractures reported as occurring after T1D diagnosis were included. Characteristics were compared between those with and without fractures.

RESULTS

Respondents included 756 adults (mean age 39 ± 16 years, 28% ≥50 years, 63% female, 90% non-Hispanic White, diabetes duration 24 ± 14 years); 48% reported ≥1 fracture since diagnosis. Of the 659 reported fractures, 24% involved metatarsal/toe, 21% metacarpal/fingers, 14% fibula/tibia, 5% hip/pelvis/femur and 3% vertebrae. Those with fracture were more likely to be older (43 ± 16 vs. 36 ± 14 years), have longer T1D duration (28 ± 14 vs. 20 ± 12 years), been diagnosed with T1D before age 20 years (79% vs. 71%) compared to those without fracture (all p-values < 0.01).

CONCLUSIONS

Data from this national sample suggest fractures in adults with T1D are common at young age and frequently involve peripheral sites. Age, longer diabetes duration, and T1D diagnosis prior to peak bone mass accrual are notable risk factors. Further research is needed to examine the impact of these determinants on fracture risk in T1D.

A 10-Year Prospective Study of Bone Mineral Density and Bone Turnover in Males and Females With Type 1 Diabetes

CONTEXT

In a previous community-based, cross-sectional study, males with type 1 diabetes (T1D) had lower bone mineral density (BMD) than did matched people without diabetes but females with T1D had normal BMD.

OBJECTIVE

To determine whether BMD in the males continued to decline, the neutral effect of T1D on BMD in females persisted, and whether temporal BMD changes reflected changes in bone turnover markers.

DESIGN

Longitudinal observational study.

SETTING

Urban community.

PATIENTS

Forty-eight of the original 102 original cross-sectional study participants (20 males, 28 females) of mean age 42.0 years and median diabetes duration 14.6 years at baseline who were restudied a mean of 10.3 years later.

MAIN OUTCOME MEASURES

BMD at total hip, femoral neck, lumbar spine (L1 to L4), and distal forearm. Biochemical bone turnover markers.

RESULTS

After adjustment for age, body mass index (BMI), and renal function, there was no temporal change in BMD at the hip or forearm in the males (P ≥ 0.12), but lumbar spine BMD increased (P = 0.009). Females exhibited no statistically significant change in BMD in similar multivariable models that also included postmenopausal status, except a mild increase at the forearm (P = 0.046). Age- and sex-related changes in bone turnover markers paralleled those in general population studies.

CONCLUSIONS

There is a reduction in BMD in males with T1D that occurs early in the course of the disease but then stabilizes. BMD in females with T1D remains similar to that expected for age, BMI, and postmenopausal status.

Comparison of osteoporosis in US adults with type 1 and type 2 diabetes mellitus

PURPOSE

We examined bone mineral density (BMD) and osteoporosis prevalence in those with type 1 compared to type 2 diabetes derived from a nationally representative sample from the civilian community in the United States.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) for 2005-2006, 2007-2008, 2009-2010, and 2013-2014 were merged to obtain a large sample of diabetics at least 20 years of age with participation in the interview and medical examination. Osteoporosis status was defined by BMD at the total femur, femoral neck, or total lumbar spine. Self-reported diabetics that were prescribed insulin within the first year of diagnosis, are currently taking insulin, and reported no prescriptions for any diabetic pills were classified as type 1. Remaining self-reported diabetics were deemed as having type 2.

RESULTS

A total of 2050 diabetics were included in which 87 (4%) were classified as type 1. Type 1 diabetics were found to have a significantly lower BMD at the total femur and femoral neck, but not at the lumbar spine in the adjusted models. Diabetics with type 1 were 4.7 times more likely to have osteoporosis than those with type 2. There was no significant relationship between diabetes type and BMD or osteoporosis prior to adjustment for confounders.

CONCLUSIONS

Although our results show an increased likelihood of osteoporosis among those with type 1 diabetes, future studies including a larger sample from a community population are needed. It may benefit diabetics, especially those with type 1, to initiate osteoporosis screening methods including evaluation of fracture risk, bone quality, and BMD measurements at multiple sites earlier than recommended.

Assessment of bone quality in patients with diabetes mellitus

Substantial evidence exists that diabetes mellitus is associated with an increased risk of osteoporotic fractures. Low bone strength as well as bone extrinsic factors are probably contributing to the increased bone fragility in diabetes. Bone density and quality are important determinants of bone strength. Although bone mineral density (BMD) and the fracture risk assessment tool (FRAX) are very useful clinical tools in assessing bone strength, they may underestimate the fracture risk in diabetes mellitus. Through advances in new technologies such as trabecular bone score (TBS) and peripheral quantitative computed tomography (pQCT), we can better assess the bone quality and fracture risk of patients with diabetes mellitus. Invasive assessments such as microindentation and histomorphometry have been great complement to the existing bone analysis techniques. Bone turnover markers have been found to be altered in diabetes mellitus patients and may be associated with fractures. This review will give a brief summary of the current development and clinical uses of these assessments.

Bone mineral density at femoral neck and lumbar spine in adults with type 1 diabetes: a meta-analysis and review of the literature

We performed a meta-analysis to evaluate the femoral neck and lumbar spine bone mineral density (BMD) in adults with type 1 diabetes (T1D) compared with controls. Adults with T1D have modestly lower BMD at femoral neck and lumbar spine than adults without diabetes.

INTRODUCTION

Fracture risk is four to sixfold higher in adults with T1D. Since BMD is one of the major contributors for fracture risk, we performed a meta-analysis to evaluate differences in femoral neck and lumbar spine BMD between adults with T1D and controls.

METHODS

MEDLINE, Ovid, and the Cochrane library and abstracts from various scientific meetings were searched. Studies reporting the femoral neck and/or lumbar spine BMD in adults (age > 20 years) with T1D in comparison with people without diabetes were selected. General linear mixed models were used to assess differences in BMD at femoral neck and lumbar spine between subjects with T1D and controls adjusting for age, sex, and dual x-ray absorptiometry (DXA) instruments.

RESULTS

Sixteen studies met the inclusion criteria. The femoral neck BMD was modestly lower in adults with T1D compared to controls (-0.055 g/cm²; 95% CI: -0.065, -0.045). There were no differences in lumbar spine BMD between adults with T1D and controls (0.0062 g/cm²; 95% CI -0.04, 0.016). However, in a sensitivity analysis, lumbar spine BMD was modestly lower in adults with T1D compared to controls (-0.035 g/cm²; -0.049, -0.02). Studies using Lunar DXA instruments have reported higher lumbar spine and femoral neck BMD compared to studies using Hologic DXA instruments.

CONCLUSION

Femoral neck and lumbar spine BMD were modestly lower in adults with T1D compared to controls. However, this modest reduction in femoral neck and lumbar spine BMD cannot explain much higher observed fracture risk in adults with T1D.

Circulating osteocalcin is unrelated to glucose homoeostasis in adults with type 1 diabetes

AIMS

To assess the relationship between total osteocalcin (tOC), undercarboxylated osteocalcin (ucOC) and a range of markers of glucose homeostasis in type 1 diabetes.

METHODS

One hundred and eight community-based Caucasian adults (53 males, 55 females) without a history of osteoporosis and with a mean±SD age 39.1±15.1years and median [inter-quartile range] type 1 diabetes duration of 14.3 [6.6-20.4] years participated in a cross-sectional study of bone health. Fasting serum glucose and HbA_1c, and serum tOC, ucOC, total adiponectin and procollagen type 1N-terminal propeptide (P1NP) were measured using validated assays, and daily insulin dose and estimated glucose disposal rate (eGDR) were calculated. Multiple linear regression was used to determine independent associates of markers of glucose homoeostasis (HbA_1c, fasting serum glucose, daily insulin dose, eGDR and serum total adiponectin).

RESULTS

In sex-adjusted multivariable regression analyses, ln(serum P1NP) was independently and inversely associated with ln(HbA_1c) and ln(serum adiponectin) (P≤0.013). Other associations included those between ln(serum vitamin D) and ln(HbA_1c) (inversely), daily insulin dose (inversely) and eGDR (positively) (P≤0.035), as well as an inverse relationship between overweight by waist circumference and ln(serum adiponectin) (P<0.001). Ln(serum tOC) and ln(serum ucOC) were not independently associated with any glucose homoeostasis marker.

CONCLUSIONS

These data from well characterized community-based adults with type 1 diabetes do not suggest that there is a role for osteocalcin in the potentially complex interplay between the skeleton and energy homoeostasis in type 1 diabetes.

Diabetes and Bone Disease

The World Health Organization estimates that diabetes mellitus occurs in more than 415 million people; this number could double by the year 2040. Epidemiologic data have shown that the skeletal system may be a target of diabetes-mediated damage, leading to the development of diabetes-induced osteoporosis. T1D and T2D have been associated with an increased risk of fracture. Bone mineral density and fracture risk prediction tools developed for the general population capture some of the risk associated with diabetes. Recent adaptations to these tools have improved their efficacy in patients with diabetes.

Derangement of calcium metabolism in diabetes mellitus: negative outcome from the synergy between impaired bone turnover and intestinal calcium absorption

Both types 1 and 2 diabetes mellitus (T1DM and T2DM) are associated with profound deterioration of calcium and bone metabolism, partly from impaired intestinal calcium absorption, leading to a reduction in calcium uptake into the body. T1DM is associated with low bone mineral density (BMD) and osteoporosis, whereas the skeletal changes in T2DM are variable, ranging from normal to increased and to decreased BMD. However, both types of DM eventually compromise bone quality through production of advanced glycation end products and misalignment of collagen fibrils (so-called matrix failure), thereby culminating in a reduction of bone strength. The underlying cellular mechanisms (cellular failure) are related to suppression of osteoblast-induced bone formation and bone calcium accretion, as well as to enhancement of osteoclast-induced bone resorption. Several other T2DM-related pathophysiological changes, e.g., osteoblast insulin resistance, impaired productions of osteogenic growth factors (particularly insulin-like growth factor 1 and bone morphogenetic proteins), overproduction of pro-inflammatory cytokines, hyperglycemia, and dyslipidemia, also aggravate diabetic osteopathy. In the kidney, DM and the resultant hyperglycemia lead to calciuresis and hypercalciuria in both humans and rodents. Furthermore, DM causes deranged functions of endocrine factors related to mineral metabolism, e.g., parathyroid hormone, 1,25-dihydroxyvitamin D3, and fibroblast growth factor-23. Despite the wealth of information regarding impaired bone remodeling in DM, the long-lasting effects of DM on calcium metabolism in young growing individuals, pregnant women, and neonates born to women with gestational DM have received scant attention, and their underlying mechanisms are almost unknown and worth exploring.

Zinc Up-Regulates Insulin Secretion from β Cell-Like Cells Derived from Stem Cells from Human Exfoliated Deciduous Tooth (SHED)

Stem cells from human exfoliated deciduous tooth (SHED) offer several advantages over other stem cell sources. Using SHED, we examined the roles of zinc and the zinc uptake transporter ZIP8 (Zrt- and irt-like protein 8) while inducing SHED into insulin secreting β cell-like stem cells (i.e., SHED-β cells). We observed that ZIP8 expression increased as SHED differentiated into SHED-β cells, and that zinc supplementation at day 10 increased the levels of most pancreatic β cell markers-particularly Insulin and glucose transporter 2 (GLUT2). We confirmed that SHED-β cells produce insulin successfully. In addition, we note that zinc supplementation significantly increases insulin secretion with a significant elevation of ZIP8 transporters in SHED-β cells. We conclude that SHED can be converted into insulin-secreting β cell-like cells as zinc concentration in the cytosol is elevated. Insulin production by SHED-β cells can be regulated via modulation of zinc concentration in the media as ZIP8 expression in the SHED-β cells increases.

Epidemiology of Skeletal Health in Type 1 Diabetes

The skeleton is adversely affected by type 1 diabetes (T1D). Patients with T1D of both sexes have an increased risk of fracture that begins in childhood and extends across the entire lifespan. T1D is characterized by mild to modest deficits in bone density, structure, and microarchitecture. Current evidence suggests that the observed bone deficits in T1D are the result of impaired bone formation rather than increased bone resorption. There is emerging data that bone quality is impaired in T1D, which may explain the findings that fracture risk is elevated out of proportion to the degree of bone mineral deficit. In this review, we summarize the current knowledge regarding the epidemiology of skeletal health in T1D. Given the high individual and societal burden of osteoporotic fracture, there is an urgent need to better understand the etiology of T1D-related bone disease so that clinical strategies to prevent fracture can be developed.

Bone disease in cystic fibrosis: new pathogenic insights opening novel therapies

Mutations within the gene encoding for the chloride ion channel cystic fibrosis transmembrane conductance regulator (CFTR) results in cystic fibrosis (CF), the most common lethal autosomal recessive genetic disease that causes a number of long-term health problems, as the bone disease. Osteoporosis and increased vertebral fracture risk associated with CF disease are becoming more important as the life expectancy of patients continues to improve. The etiology of low bone density is multifactorial, most probably a combination of inadequate peak bone mass during puberty and increased bone losses in adults. Body mass index, male sex, advanced pulmonary disease, malnutrition and chronic therapies are established additional risk factors for CF-related bone disease (CFBD). Consistently, recent evidence has confirmed that CFTR plays a major role in the osteoprotegerin (OPG) and COX-2 metabolite prostaglandin E2 (PGE2) production, two key regulators in the bone formation and regeneration. Several others mechanisms were also recognized from animal and cell models contributing to malfunctions of osteoblast (cell that form bone) and indirectly of bone-resorpting osteoclasts. Understanding such mechanisms is crucial for the development of therapies in CFBD. Innovative therapeutic approaches using CFTR modulators such as C18 have recently shown in vitro capacity to enhance PGE2 production and normalized the RANKL-to-OPG ratio in human osteoblasts bearing the mutation F508del-CFTR and therefore potential clinical utility in CFBD. This review focuses on the recently identified pathogenic mechanisms leading to CFBD and potential future therapies for treating CFBD.

MECHANISMS IN ENDOCRINOLOGY: Mechanisms and evaluation of bone fragility in type 1 diabetes mellitus

Subjects with type 1 diabetes mellitus (T1DM) have decreased bone mineral density and an up to sixfold increase in fracture risk. Yet bone fragility is not commonly regarded as another unique complication of diabetes. Both animals with experimentally induced insulin deficiency syndromes and patients with T1DM have impaired osteoblastic bone formation, with or without increased bone resorption. Insulin/IGF1 deficiency appears to be a major pathogenetic mechanism involved, along with glucose toxicity, marrow adiposity, inflammation, adipokine and other metabolic alterations that may all play a role on altering bone turnover. In turn, increasing physical activity in children with diabetes as well as good glycaemic control appears to provide some improvement of bone parameters, although robust clinical studies are still lacking. In this context, the role of osteoporosis drugs remains unknown.

Sclerostin antibody treatment improves fracture outcomes in a Type I diabetic mouse model

Type 1 diabetes mellitus (T1DM) patients have osteopenia and impaired fracture healing due to decreased osteoblast activity. Further, no adequate treatments are currently available that can restore impaired healing in T1DM; hence a significant need exists to investigate new therapeutics for treatment of orthopedic complications. Sclerostin (SOST), a WNT antagonist, negatively regulates bone formation, and SostAb is a potent bone anabolic agent. To determine whether SOST antibody (SostAb) treatment improves fracture healing in streptozotocin (STZ) induced T1DM mice, we administered SostAb twice weekly for up to 21days post-fracture, and examined bone quality and callus outcomes at 21days and 42days post-fracture (11 and 14weeks of age, respectively). Here we show that SostAb treatment improves bone parameters; these improvements persist after cessation of antibody treatment. Markers of osteoblast differentiation such as Runx2, collagen I, osteocalcin, and DMP1 were reduced, while an abundant number of SP7/osterix-positive early osteoblasts were observed on the bone surface of STZ calluses. These results suggest that STZ calluses have poor osteogenesis resulting from failure of osteoblasts to fully differentiate and produce mineralized matrix, which produces a less mineralized callus. SostAb treatment enhanced fracture healing in both normal and STZ groups, and in STZ+SostAb mice, also reversed the lower mineralization seen in STZ calluses. Micro-CT analysis of calluses revealed improved bone parameters with SostAb treatment, and the mineralized bone was comparable to Controls. Additionally, we found sclerostin levels to be elevated in STZ mice and β-catenin activity to be reduced. Consistent with its function as a WNT antagonist, SostAb treatment enhanced β-catenin activity, but also increased the levels of SOST in the callus and in circulation. Our results indicate that SostAb treatment rescues the impaired osteogenesis seen in the STZ induced T1DM fracture model by facilitating osteoblast differentiation and mineralization of bone.

Bone Geometry, Volumetric Density, Microarchitecture, and Estimated Bone Strength Assessed by HR-pQCT in Adult Patients With Type 1 Diabetes Mellitus

The primary goal of this cross-sectional in vivo study was to assess peripheral bone microarchitecture, bone strength, and bone remodeling in adult type 1 diabetes (T1D) patients with and without diabetic microvascular disease (MVD+ and MVD-, respectively) and to compare them with age-, gender-, and height-matched healthy control subjects (CoMVD+ and CoMVD-, respectively). The secondary goal was to assess differences in MVD- and MVD+ patients. Fifty-five patients with T1DM (MVD+ group: n = 29) were recruited from the Funen Diabetes Database. Dual-energy X-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT) of the ultradistal radius and tibia, and biochemical markers of bone turnover were performed in all participants. There were no significant differences in HR-pQCT parameters between MVD- and CoMVD- subjects. In contrast, MVD+ patients had larger total and trabecular bone areas (p = 0.04 and p = 0.02, respectively), lower total, trabecular, and cortical volumetric bone mineral density (vBMD) (p < 0.01, p < 0.04, and p < 0.02, respectively), and thinner cortex (p = 0.03) at the radius, and lower total and trabecular vBMD (p = 0.01 and p = 0.02, respectively) at the tibia in comparison to CoMVD+. MVD+ patients also exhibited lower total and trabecular vBMD (radius p = 0.01, tibia p < 0.01), trabecular thickness (radius p = 0.01), estimated bone strength, and greater trabecular separation (radius p = 0.01, tibia p < 0.01) and network inhomogeneity (radius p = 0.01, tibia p < 0.01) in comparison to MVD- patients. These differences remained significant after adjustment for age, body mass index, gender, disease duration, and glycemic control (average glycated hemoglobin over the previous 3 years). Although biochemical markers of bone turnover were significantly lower in MVD+ and MVD- groups in comparison to controls, they were similar between the MVD+ and MVD- groups. The results of our study suggest that the presence of MVD was associated with deficits in cortical and trabecular bone vBMD and microarchitecture that could partly explain the excess skeletal fragility observed in these patients.

Bisphosphonate treatment of type I diabetic mice prevents early bone loss but accentuates suppression of bone formation

Type I (T1) diabetes is an autoimmune and metabolic disease associated with bone loss. Previous studies demonstrate that T1-diabetes decreases osteoblast activity and viability. Bisphosphonate therapy, commonly used to treat osteoporosis, is demonstrated to inhibit osteoclast activity as well as osteoblast apoptosis. Therefore, we examined the effect of weekly alendronate treatments on T1-diabetes induced osteoblast apoptosis and bone loss. Bone TUNEL assays identified that alendronate therapy prevents the diabetes-induced osteoblast death observed during early stages of diabetes development. Consistent with this, alendronate treatment for 40 days was able to prevent diabetes-induced trabecular bone loss. Alendronate was also able to reduce marrow adiposity in both control diabetic mice compared to untreated mice. Mechanical testing indicated that 40 days of alendronate treatment increased bone stiffness but decreased the work required for fracture in T1-diabetic and alendronate treated mice. Of concern at this later time point, bone formation rate and osteoblast markers, which were already decreased in diabetic mice, were further suppressed in alendronate-treated diabetic mice. Taken together, our results suggest that short-term alendronate treatment can prevent T1-diabetes-induced bone loss in mice, possibly in part by inhibiting diabetes onset associated osteoblast death, while longer treatment enhanced bone density but at the cost of further suppressing bone formation in diabetic mice.

Different health behaviours and clinical factors associated with bone mineral density and bone turnover in premenopausal women with and without type 1 diabetes

BACKGROUND

Women with type 1 diabetes (T1DM) have an elevated fracture risk. We therefore compared the associations of health behaviours and clinical factors with bone mineral density (BMD) and bone remodelling between premenopausal women with and without T1DM to inform potential interventions.

METHODS

Participants included women with T1DM (n = 89) from the Wisconsin Diabetes Registry Study and age-matched and race-matched controls without diabetes (n = 76). Peripheral (heel and forearm) and central (hip and spine) BMD, markers of bone resorption and formation, bone cell signalling, glycaemic control, and kidney function were assessed. Health behaviours and medical history were self-reported.

RESULTS

In controls, but not in women with T1DM, older age was associated with lower bone resorption (p ≤ 0.006) and formation (p = 0.0007). Body mass index was positively associated with heel and forearm BMD in both controls and T1DM women (all p < 0.0001), but with hip and spine BMD only in controls (p ≤ 0.005). Worse glycaemic control during the previous 10 years, greater alcohol intake, history of smoking, and lack of physical activity were associated with poorer bone outcomes only in women with T1DM (all p ≤ 0.002), whereas use of hormonal contraceptives was related to low bone formation in both women with and without T1DM (all p ≤ 0.006). Diabetes duration, insulin dose, residual C-peptide, and kidney function were not associated with bone in T1DM.

CONCLUSIONS

Age and body mass index may not predict bone health in T1DM women. However, modifiable behaviours such as optimizing glycaemic control, limiting substance and hormonal contraceptive use, and increasing physical activity may improve bone health in T1DM women.

An update on diabetes related skeletal fragility

There are several mechanisms by which diabetes could affect bone mass and strength. These mechanisms include insulin deficiency; hyperglycemia; the accumulation of advanced glycation end products that may influence collagen characteristics; marrow adiposity and bone inflammation. Furthermore, associated diabetic complications and treatment with thaizolidinediones may also increase risk of fracturing. The following article provides its readers with an update on the latest information pertaining to diabetes related bone skeletal fragility. In the authors' opinion, future studies are needed in order to clarify the impact of different aspects of diabetes metabolism, glycemic control, and specific treatments for diabetes on bone. Given that dual energy x-ray absorptiometry is a poor predictor of bone morbidity in this group of patients, there is a need to explore novel approaches for assessing bone quality. It is important that we develop a better understanding of how diabetes affects bone in order to improve our ability to protect bone health and prevent fractures in the growing population of adults with diabetes.

Type 1 diabetes and osteoporosis: from molecular pathways to bone phenotype

The link between type 1 diabetes mellitus (DM1) and osteoporosis, identified decades ago, has gained attention in recent years. While a number of cellular mechanisms have been postulated to mediate this association, it is now established that defects in osteoblast differentiation and activity are the main culprits underlying bone fragility in DM1. Other contributing factors include an accumulation of advanced glycation end products (AGEs) and the development of diabetes complications (such as neuropathy and hypoglycemia), which cause further decline in bone mineral density (BMD), worsening geometric properties within bone, and increased fall risk. As a result, patients with DM1 have a 6.9-fold increased incidence of hip fracture compared to controls. Despite this increased fracture risk, bone fragility remains an underappreciated complication of DM1 and is not addressed in most diabetes guidelines. There is also a lack of data regarding the efficacy of therapeutic strategies to treat osteoporosis in this patient population. Together, our current understanding of bone fragility in DM1 calls for an update of diabetes guidelines, better screening tools, and further research into the use of therapeutic strategies in this patient population.

Time dependent changes in the intestinal Ca²⁺ absorption in rats with type I diabetes mellitus are associated with alterations in the intestinal redox state

The aim was to determine the intestinal Ca²⁺ absorption in type I diabetic rats after different times of STZ induction, as well as the gene and protein expression of molecules involved in both the transcellular and paracellular Ca²⁺ pathways. The redox state and the antioxidant enzymes of the enterocytes were also evaluated in duodenum from either diabetic or insulin-treated diabetic rats as compared to control rats. Male Wistar rats (150-200 g) were divided into two groups: 1) controls and 2) STZ-induced diabetic rats (60 mg/kg b.w.). A group of diabetic rats received insulin for five days. The insulin was adjusted daily to maintain a normal blood glucose level. Five 5 d after STZ injection, there was a reduction in the intestinal Ca²⁺ absorption, which was maintained for 30 d and disappeared at 60 d. Similar changes occurred in the GSH and (˙)O(2)(-) levels. The protein expression of molecules involved in the transcellular pathway increased at 5 and 30 d returning to control values at 60 d. Their mRNA levels declined considerably at 60 d. The gene and protein expression of claudin 2 was upregulated at 30 d. Catalase activity increased at 5 and 30 d normalizing at 60 d. To conclude, type I D.m. inhibits the intestinal Ca²⁺ absorption, which is transient leading to a time dependent adaptation and returning the absorptive process to normal values. The inhibition is accompanied by oxidative stress. When insulin is administered, the duodenal redox state returns to control values and the intestinal Ca²⁺ absorption normalizes.

Association between bone mineral density and type 1 diabetes mellitus: a meta-analysis of cross-sectional studies

A few studies have investigated the relationship between type 1 diabetes mellitus (T1DM) and bone mineral density (BMD) values. This meta-analysis was performed to explore differences between T1DM and healthy individuals in BMD values measured at five bone sites.We searched the database of PubMed for cross-sectional studies about the association of T1DM and BMD, and a meta-analysis was conducted.The results suggested significant association between T1DM and decreased BMD values of total body. The pooled mean differences (MDs) were -0.06 [95% confidence interval (CI): -0.11, -0.01] for all people. As for the association between T1DM and spine BMD values, the pooled MDs were -0.04 (95% CI: -0.07, -0.01) for males and -0.03 (95% CI: -0.06, 0.00) for females <20 years old. As for femur BMD values, the pooled MDs were -0.06 (95% CI: -0.13, 0.00) for all people, -0.03 (95% CI: -0.06, -0.01) for females and -0.04(95% CI: -0.05, -0.02) for males. As for hip BMD values, the pooled MDs were -0.06 (95% CI: -0.08, -0.04) for females. As for forearm BMD values, the pooled MDs were -0.01 (95% CI: -0.02, 0.00) for females.The results of this meta-analysis suggest the overall association between T1DM and reduced BMD values. Notably, the influence of T1DM on BMD seems to depend on gender or patient's age. Reduced BMD values may occur early after T1DM diagnosis. Future clinical and basic research studies are needed to further understand the mechanisms of decreased BMD values in T1DM patients.

High dietary cholesterol masks type 2 diabetes-induced osteopenia and changes in bone microstructure in rats

Type 2 diabetes mellitus (T2DM) often occurs concurrently with high blood cholesterol or dyslipidemia. Although T2DM has been hypothesized to impair bone microstructure, several investigations showed that, when compared to age-matched healthy individuals, T2DM patients had normal or relatively high bone mineral density (BMD). Since cholesterol and lipids profoundly affect the function of osteoblasts and osteoclasts, it might be cholesterol that obscured the changes in BMD and bone microstructure in T2DM. The present study, therefore, aimed to determine bone elongation, epiphyseal histology, and bone microstructure in non-obese T2DM Goto-Kakizaki rats treated with normal (GK-ND) and high cholesterol diet. We found that volumetric BMD was lower in GK-ND rats than the age-matched wild-type controls. In histomorphometric study of tibial metaphysis, T2DM evidently suppressed osteoblast function as indicated by decreases in osteoblast surface, mineral apposition rate, and bone formation rate in GK-ND rats. Meanwhile, the osteoclast surface and eroded surface were increased in GK-ND rats, thus suggesting an activation of bone resorption. T2DM also impaired bone elongation, presumably by retaining the chondrogenic precursor cells in the epiphyseal resting zone. Interestingly, several bone changes in GK rats (e.g., increased osteoclast surface) disappeared after high cholesterol treatment as compared to wild-type rats fed high cholesterol diet. In conclusion, high cholesterol diet was capable of masking the T2DM-induced osteopenia and changes in several histomorphometric parameters that indicated bone microstructural defect. Cholesterol thus explained, in part, why a decrease in BMD was not observed in T2DM, and hence delayed diagnosis of the T2DM-associated bone disease.

Bone Health in Type 1 Diabetes: Where We Are Now and How We Should Proceed

Type 1 diabetes (T1D) is autoimmune disease with chronic hyperglycaemic state. Besides diabetic retinopathy, nephropathy, and neuropathy, T1D is characterized by poor bone health. The reduced bone mineralization and quality/strength, due to hyperglycemia, hypoinsulinemia, autoimmune inflammation, low levels of insulin growth factor-1 (IGF-1), and vitamin D, lead to vertebral/hip fractures. Young age of T1D manifestation, chronic poor glycemic control, high daily insulin dose, low BMI, reduced renal function, and the presence of complications can be helpful in identifying T1D patients at risk of reduced bone mineral density. Although risk factors for fracture risk are still unknown, chronic poor glycemic control and presence of diabetic complications might raise the suspicion of elevated fracture risk in T1D. In the presence of the risk factors, the assessment of bone mineral density by dual-energy X-ray absorptiometry and the search of asymptomatic vertebral fracture by lateral X-ray radiography of thorax-lumbar spine should be recommended. The improvement of glycemic control may have a beneficial effect on bone in T1D. Several experiments showed promising results on using anabolic pharmacological agents (recombinant IGF-1 and parathyroid hormone) in diabetic rodents with bone disorder. Randomized clinical trials are needed in order to test the possible use of bone anabolic therapies in humans with T1D.

Effects of type 1 diabetes, sprint training and sex on skeletal muscle sarcoplasmic reticulum Ca2+ uptake and Ca2+-ATPase activity

Calcium cycling is integral to muscle performance during the rapid muscle contraction and relaxation of high-intensity exercise. Ca(2+) handling is altered by diabetes mellitus, but has not previously been investigated in human skeletal muscle. We investigated effects of high-intensity exercise and sprint training on skeletal muscle Ca(2+) regulation among men and women with type 1 diabetes (T1D, n = 8, 3F, 5M) and matched non-diabetic controls (CON, n = 8, 3F, 5M). Secondarily, we examined sex differences in Ca(2+) regulation. Subjects undertook 7 weeks of three times-weekly cycle sprint training. Before and after training, performance was measured, and blood and muscle were sampled at rest and after high-intensity exercise. In T1D, higher Ca(2+)-ATPase activity (+28%) and Ca(2+) uptake (+21%) than in CON were evident across both times and days (P < 0.05), but performance was similar. In T1D, resting Ca(2+)-ATPase activity correlated with work performed until exhaustion (r = 0.7, P < 0.01). Ca(2+)-ATPase activity, but not Ca(2+) uptake, was lower (-24%, P < 0.05) among the women across both times and days. Intense exercise did not alter Ca(2+)-ATPase activity in T1D or CON. However, sex differences were evident: Ca(2+)-ATPase was reduced with exercise among men but increased among women across both days (time × sex interaction, P < 0.05). Sprint training reduced Ca(2+)-ATPase (-8%, P < 0.05), but not Ca(2+) uptake, in T1D and CON. In summary, skeletal muscle Ca(2+) resequestration capacity was increased in T1D, but performance was not greater than CON. Sprint training reduced Ca(2+)-ATPase in T1D and CON. Sex differences in Ca(2+)-ATPase activity were evident and may be linked with fibre type proportion differences.

Cystic fibrosis-related bone disease: insights into a growing problem

PURPOSE OF REVIEW

This review will describe the clinical significance, pathogenesis and treatment of cystic fibrosis related bone disease (CFBD).

RECENT FINDINGS

CFBD continues to increase as the life expectancy of individuals with cystic fibrosis increases. According to clinical guidelines, individuals with cystic fibrosis should be initially screened at the age of 18 years via dual-energy x-ray absorptiometry, if not done so previously. The underlying pathogenesis of CFBD appears to be multifactorial, but increasing data imply a direct impact by the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR deficiency and/or dysfunction impair osteoblast activity and differentiation, and indirectly promote osteoclast formation. Unfortunately, once diagnosed with CFBD, few cystic fibrosis tested medical therapies exist.

SUMMARY

CFBD is an increasingly recognized complication that has a significant impact on the overall health of the individual. Recommendations to identify patients with cystic fibrosis who are at risk for fracture using dual-energy x-ray absorptiometry have been established. Therapeutic agents directly studied in patients with cystic fibrosis are limited to bisphosphonates, although other potential treatment agents exist. Finally, an improved understanding of the pathologic mechanisms will aid in the study and development of therapies.

COMP-Ang1 inhibits apoptosis as well as improves the attenuated osteogenic differentiation of mesenchymal stem cells induced by advanced glycation end products

BACKGROUND

In the present study, we have investigated the possibility that cartilage oligomeric matrix protein angiopoietin1 (COMP-Ang1), important factor in angiogenesis, osteogenesis and the survival of mesenchymal stem cells (MSCs) through the Ang1/Tie2 pathway has beneficial effects on osteogenic differentiated cells (ODCs) from MSCs treated by advanced glycation end products (AGE), which are pathological factors of diabetes.

METHODS

Primary culture of MSCs was used. For comparison analysis of AGE and COMP-Ang1 effects, we performed cell viability assay with each treated variety concentration for 24h. Apoptosis rate and Caspase-3 activity were measured by each ELISA assay. To make sure with Ang1/Tie2 pathway, we performed small interfering RNA transfected to MSCs. Real-time RT-PCR was performed to identify ODCs marker genes. Immunoblotting was used to evaluate the expression of Tie2, AKT, p38 and ERK.

RESULTS

Our results clearly demonstrate that COMP-Ang1 upregulates the phosphorylation of AKT and p38 by activating the Ang1/Tie2 signaling pathway, indicating that COMP-Ang1 affects both AGE-induced apoptosis and the attenuated osteogenic differentiation of MSCs through the p38/MAPK and PI3K/AKT pathways.

CONCLUSIONS

COMP-Ang1 improves cell viability and differentiation function of ODCs against AGE via Ang/Tie2 signaling pathway.

GENERAL SIGNIFICANCE

Our results suggest the potential importance of COMP-Ang1 as a new therapy for impaired bone formation that is associated with diabetes and advanced age.

Prevalence of morphometric vertebral fractures in patients with type 1 diabetes

OBJECTIVE

Several studies showed low bone mineral density (BMD) and elevated risk of symptomatic fractures in patients with type 1 diabetes (T1D). To our knowledge, there has been no investigation on the prevalence of asymptomatic vertebral fractures (VFx) in T1D. In the current study, we assessed BMD and the prevalence of VFx in T1D.

RESEARCH DESIGN AND METHODS

We evaluated 82 T1D patients (26 males and 56 females, aged 31.1 ± 8.6 years, BMI 23.5 ± 3.3 kg/m(2), disease duration 12.8 ± 8.3 years) and 82 controls (22 females and 60 males, aged 32.9 ± 5.8 years, BMI 23.9 ± 4.8 kg/m(2)). Spinal and femoral BMD (as Z-score, Z-LS and Z-FN, respectively) and the prevalence of VFx were evaluated by dual X-ray absorptiometry.

RESULTS

T1D patients had lower Z-LS and Z-FN than controls (-0.55 ± 1.3 vs. 0.35 ± 1.0, P < 0.0001, and -0.64 ± 1.1 vs. 0.29 ± 0.9, P < 0.0001, respectively) and a higher prevalence of VFx (24.4 vs. 6.1%, P = 0.002). Age, diabetes duration, age at diabetes manifestation, glycosylated hemoglobin, Z-LS, Z-FN, and the prevalence of chronic complications were similar for patients with and without VFx. In the logistic regression analysis, the presence of VFx was associated with the presence of T1D but not with lumbar spine BMD. Whereas moderate or severe VFx was associated with low lumbar spine BMD in the whole combined group of T1D patients and controls, there was no association between moderate or severe VFx and lumbar spine BMD in the T1D group.

CONCLUSIONS

T1D patients have low BMD and elevated prevalence of asymptomatic VFx, which is associated with the presence of T1D independently of BMD.

A five-year prospective study of bone mineral density in men and women with diabetes: the Fremantle Diabetes Study

To examine longitudinally the effect of diabetes on bone structure and metabolism, we measured bone mineral density (BMD) and turnover markers in 26 type 1 (mean age 49 years) and 27 type 2 (mean age 65 years) diabetic patients without known osteoporosis from a community-based sample at baseline and 5 years later. In the 17 type 1 men, BMD fell at the femoral neck (0.804 ± 0.145 vs. 0.769 ± 0.129 g/cm(2); P = 0.003) with no change at lumbar spine or forearm. In the 11 type 2 women, BMD decreased at all sites except spine (femoral neck 0.779 ± 0.119 vs. 0.742 ± 0.090 g/cm(2); P = 0.019). BMD did not fall at any site in type 1 women or type 2 men. There was an increase in serum alkaline phosphatase and trend to higher serum beta carboxyl-terminal type I collagen telopeptide concentrations in the type 1 patients, and a decrease in free testosterone in the type 1 men. These data show that the rate of demineralization at the femoral neck in type 1 men is similar to that in older post-menopausal type 2 women. Changes in biochemical markers suggest that, in type 1 men, there is ineffective bone formation associated with accelerated bone resorption and lower sex steroid bioavailability. These findings may have implications for the clinical management of young male adults with diabetes.

Insulin resistance in type 2 diabetes mellitus may be related to bone mineral density

The mechanism of bone mineral density (BMD) changes in type 2 diabetes mellitus is not clear. We aimed to investigate the effect of insulin resistance in type 2 diabetics on BMD. Insulin resistance was determined using the homeostasis model assessment index (HOMA-IR). Nineteen type 2 diabetic patients with a HOMA-IR <2.7 (mean age, 51.5±9.6yr; body mass index [BMI], 27.3±5.1kg/m(2); duration of diabetes, 10.5±7.3yr) were included in Group A, and 30 BMI- and age-matched type 2 diabetic patients with a HOMA-IR ≥2.7 were included in Group B. The BMD was measured with dual-energy X-ray absorptiometry. Independent t-test was used for statistical analysis. The Group A values for mean fasting glucose and insulin levels were 160.1±77.0mg/dL and 4.79±2.89μU/L, respectively, whereas the Group B values were 195.1±58.9mg/dL (p>0.05) and 19.30±16.89μU/L (p=0.0001). Significantly higher total lumbar vertebra T-score (p=0.02) and total lumbar vertebra BMD in Group A were determined than Group B (p=0.033). The lumbar vertebra total Z-score was significantly lower in Group B (p=0.042). Marked insulin resistance may have a negative effect on BMD in type 2 diabetics, while the presence of hyperinsulinemia may be associated with the low BMD.

Oxidative stress and heme oxygenase-1 regulated human mesenchymal stem cells differentiation

This paper describes the effect of increased expression of HO-1 protein and increased levels of HO activity on differentiation of bone-marrow-derived human MSCs. MSCs are multipotent cells that proliferate and differentiate into many different cell types including adipocytes and osteoblasts. HO, the rate-limiting enzyme in heme catabolism, plays an important role during MSCs differentiation. HO catalyzes the stereospecific degradation of heme to biliverdin, with the concurrent release of iron and carbon monoxide. Upregulation of HO-1 expression and increased HO activity are essential for MSC growth and differentiation to the osteoblast lineage consistent with the role of HO-1 in hematopoietic stem cell differentiation. HO-1 participates in the MSC differentiation process shifting the balance of MSC differentiation in favor of the osteoblast lineage by decreasing PPARγ and increasing osteogenic markers such as alkaline phosphatase and BMP-2. In this paper, we define HO-1 as a target molecule in the modulation of adipogenesis and osteogenesis from MSCs and examine the role of the HO system in diabetes, inflammation, osteoporosis, hypertension, and other pathologies, a burgeoning area of research.

[Clinical practice guidelines for evaluation and treatment of osteoporosis associated to endocrine and nutritional conditions. Bone Metabolism Working Group of the Spanish Society of Endocrinology]

OBJECTIVE

To provide practical recommendations for evaluation and treatment of osteoporosis associated to endocrine diseases and nutritional conditions.

PARTICIPANTS

Members of the Bone Metabolism Working Group of the Spanish Society of Endocrinology, a methodologist, and a documentalist.

METHODS

Recommendations were formulated according to the GRADE system (Grading of Recommendations, Assessment, Development, and Evaluation) to describe both the strength of recommendations and the quality of evidence. A systematic search was made in MEDLINE (Pubmed), using the following terms associated to the name of each condition: AND "osteoporosis", "fractures", "bone mineral density", and "treatment". Papers in English with publication date before 18 October 2011 were included. Current evidence for each disease was reviewed by two group members, and doubts related to the review process or development of recommendations were resolved by the methodologist. Finally, recommendations were discussed in a meeting of the Working Group.

CONCLUSIONS

The document provides evidence-based practical recommendations for evaluation and management of endocrine and nutritional diseases associated to low bone mass or an increased risk of fracture. For each disease, the associated risk of low bone mass and fragility fractures is given, recommendations for bone mass assessment are provided, and treatment options that have shown to be effective for increasing bone mass and/or to decreasing fragility fractures are listed.

Highlights from the 37th Annual Meeting for ISPAD, Miami

The 37th Annual Meeting for the International Society of Pediatric and Adolescent Diabetes was held in Miami Beach, Florida, USA. The meeting, titled 'Possibilities for Prevention and Diabetes and its Complications', attracted over 1000 delegates from 52 countries. Fifty-six oral abstracts were presented, along with 294 posters, representing the diversity of research and clinical innovations in the field of pediatric and adolescent diabetes around the world. Abstracts to the Oral and Poster Sessions can be found in a recent supplement of Pediatric Diabetes. Here are some highlights from the plenary sessions, symposia, and oral presentations.

Human bone marrow adiposity is linked with serum lipid levels not T1-diabetes

Increased marrow adiposity is often associated with bone loss. Little is known about the regulation of marrow adiposity in humans. Marrow adiposity is increased in several mouse models including type I (T1)-diabetic mice, which also display bone loss. However, the impact of metabolic disease on marrow adiposity in humans has yet to be examined. This study measured bone marrow adiposity levels with iterative decomposition of water and fat with echo asymmetry and least-squares estimation magnetic resonance imaging and determined their relationship with T1-diabetes, bone mineral density (BMD), and serum lipid levels. Participants were adult T1-diabetic patients (glycosylated hemoglobin averaging 7.70%±0.4%) and age- and body-mass-index-matched nondiabetic subjects. Consistent with previous reports, serum osteocalcin levels were lower in subjects with T1-diabetes compared to controls (reaching statistical significance in females) and negatively correlated with disease duration (r=-0.50, P<.01). Furthermore, femur neck BMD inversely correlated with diabetes severity (r=-0.417, P<.05). While marrow adiposity was not altered by T1-diabetes, there was a striking positive correlation between vertebral, femur, and tibia marrow adiposity and serum lipid levels (low-density lipoprotein, total cholesterol, cholesterol:high-density lipoprotein ratio, and triglyceride; r≥0.383), reaching a significance of P<.001 in some comparisons. Marrow adiposity also displayed strong intrasubject correlations at multiple bone sites (r≥0.411, P<.05), increased with age (r=0.410, P<.05 at vertebral sites), and was reciprocally related to bone density (r≥-0.378, P<.05). Taken together, our data suggest that marrow adiposity may be an indicator of elevated serum lipid levels and decreased bone density.

Vitamin D receptor gene BsmI, FokI, ApaI, TaqI polymorphisms and bone mineral density in a group of Turkish type 1 diabetic patients

Previous studies have suggested an influence of vitamin D receptor alleles on bone metabolism and on susceptibility to type 1 diabetes mellitus in different ethnic populations. We aimed to investigate the distribution of vitamin D receptor (VDR) alleles in relation to biochemical bone turnover parameters and bone densitometry measurements in a group of Turkish type 1 diabetic patients. One hundred and seventeen patients (M/F 57/60, 27.6 ± 7.3 y duration of diabetes 8.1 ± 6.3 y) and 134 healthy controls (M/F 61/73, 26.2 ± 5.3 y) were included in the study. Bone mineral density (BMD) was evaluated by dual-energy X-ray absorptiometry (DEXA). The vitamin D receptor gene (VDR) polymorphisms FokI, Bsm1, Apa1, and Taq1 were examined using a PCR-based restriction analysis. Serum levels of calcium, phosphor osteocalcin, intact parathyroid hormone, and C telopeptide were measured. Vitamin D receptor Bsm1 Fok1, Apa1, and Taq1 genotype distributions were not different between patient with diabetes and control groups. BMD was 0.77 ± 0.2 g/cm(2) vs. 0.97 ± 0.2 g/cm(2) (P = 0.0001) for the femur, 1.0 ± 0.1 g/cm(2) vs. 1.13 ± 0.1 g/cm(2) (P = 0.001) for type 1 diabetic patients and controls. Bone turnover markers were significantly lower in type 1 diabetic group. BMD measurements and bone metabolic markers were not different between the genotypes in either the patient with diabetes or the controls. The VDR gene polymorphisms, Bsm1, Fok 1, Apa1, and Taq1 showed no influence on bone metabolism in our group of type 1 diabetic patients.

Metabolic control and bone health in adolescents with type 1 diabetes

Background

Adults with type 1 diabetes (T1D) have decreased bone mineral density (BMD) and increased fracture risk, yet the etiologies remain elusive. Early detection of derangements in bone biomarkers during adolescence could lead to timely recognition. In adolescents with T1D, we evaluated the relationships between metabolic control, BMD, and bone anabolic and turnover markers.

Methods

Cross-sectional study of 57 adolescent subjects with T1D who had HbA1c consistently ≥ 9% (Poor Control, PC n = 27) or < 9% (Favorable Control, FC n = 30) for two years prior to enrollment. Subjects had T1DM for at least three years and were without diabetes complications, known celiac disease, or other chronic diseases.

Results

There were no differences between HbA1c groups in BMD, components of the IGF system, or 25-hydroxyvitamin D status. The prevalence of 25-hydroxyvitamin D abnormalities was similar to that seen in the general adolescent population. Few patients met the recommended dietary allowance (RDA) for vitamin D or calcium.

Conclusions

These data provide no evidence of association between degree of metabolic control and BMD in adolescents with T1D. Adolescents with T1D have a high prevalence of serum 25-hydroxyvitamin D abnormalities. Longitudinal studies are needed to evaluate the predictive value of vitamin D abnormalities on fracture risk.

Osteoporosis in men with diabetes mellitus

Osteoporosis is more common in women than in men. The prevalence in men is not defined yet; however it is becoming much more recognized as its prevalence and impact have become explicable. It is estimated that around 1% of bone mineral density is lost in men every year. Studies show that secondary osteoporosis is the major cause thus, making it important to define the disorders associated with male osteoporosis. Diabetes is a risk factor for bone fractures. In male patients with diabetes measures should be undertaken such as encouraging exercise, assuring adequate calcium and vitamin D intake, and treating diabetic complications.

Osteoporosis in diabetes mellitus: Possible cellular and molecular mechanisms

Osteoporosis, a global age-related health problem in both male and female elderly, insidiously deteriorates the microstructure of bone, particularly at trabecular sites, such as vertebrae, ribs and hips, culminating in fragility fractures, pain and disability. Although osteoporosis is normally associated with senescence and estrogen deficiency, diabetes mellitus (DM), especially type 1 DM, also contributes to and/or aggravates bone loss in osteoporotic patients. This topic highlight article focuses on DM-induced osteoporosis and DM/osteoporosis comorbidity, covering alterations in bone metabolism as well as factors regulating bone growth under diabetic conditions including, insulin, insulin-like growth factor-1 and angiogenesis. Cellular and molecular mechanisms of DM-related bone loss are also discussed. This information provides a foundation for the better understanding of diabetic complications and for development of early screening and prevention of osteoporosis in diabetic patients.

Ultrasound bone measurement in an older population with metabolic syndrome

BACKGROUND AND AIMS

Metabolic syndrome and osteoporosis are recognized as major public health problems in many countries. This study investigated the association between bone quality and components of metabolic syndrome in an elderly population.

METHODS

The study included a population sample of 211 men and women, of mean age 77.9 ± 4.5 years. Anthropometry, blood pressure, serum levels of lipoproteins (HDL and LDL), triglycerides and glucose were measured, and ultrasound bone densitometry was performed in all subjects. Information on lifestyle habits, including physical activity, smoking and alcohol consumption, were obtained by a questionnaire.

RESULTS

Metabolic syndrome, defined by the criteria of the International Diabetes Federation, was determined in 59% of men and 65% of women. The quantitative ultrasound index (QUI) was significantly correlated with serum glucose in men (r=-0.31; p=0.005) and with body mass index (BMI) in women (r=0.39; p<0.0001). QUI was significantly lower in men with metabolic syndrome (F=7.57; p<0.007) and significantly higher in women with it (F=6.47; p=0.012) compared with controls. When QUI was adjusted for body mass index in women and for serum glucose in men, it was no longer significantly different from values for controls. Other covariates such as cholesterol, blood pressure, smoking, alcohol, and physical activity did not change the difference in QUI between patients with metabolic syndrome and controls. Diabetes in men (p=0.005) and obesity and waist circumference in women (p<0.05) were also significant predictors of QUI in regression analysis.

CONCLUSIONS

The association between metabolic syndrome and bone stiffness in elderly people may be explained by increased BMI in women and high serum glucose in men.