Increased low-density lipoprotein cholesterol level is associated with non-vertebral fractures in postmenopausal women

Evaluation of mandibular trabecular and cortical structure by fractal analysis in hyperlipidemia and hypertension patients

INTRODUCTION

This study aimed to evaluate the mandibular trabecular and cortical changes in patients with hyperlipidemia (HL) and/or hypertension (HT) using fractal dimension (FD) analysis, mandibular cortical width (MCW), panoramic mandibular index (PMI) and mandibular cortical index (MCI).

MATERIALS AND METHODS

Panoramic radiographs of 100 patients were evaluated. FD measurement of three region of interest (ROI) including the angulus, corpus and interdental bone area were made. MCW, PMI and MCI were also measured and noted.

RESULTS

Angulus, corpus and interdental FD values were significantly lower in three disease groups than the control group. Angulus, corpus, and interdental FD values were significantly lower in the HL+HT group than in the HL group and HT group. MCW value was significantly lower in the HL group, HT group, and HL+HT group than the control group. The cortical index C1 was more common in the control group while C2 was more common in the HT, HL and HL+HT group.

CONCLUSION

The fact that FD was significantly lower in the HL+HT group compared to the HL and HT groups indicates the positive effect of their association on bone loss and quality. FD measurements on images obtained using a direct digital panoramic system can be used for treatment planning and follow-up of patients with HL and/or HT.

Association of nuclear magnetic resonance-based metabolomics with bone health in the UK Biobank

OBJECTIVES

The study aimed to explore associations of metabolomic data based on nuclear magnetic resonance (NMR) with the risk of fractures and bone mineral density (BMD).

METHODS

We included 69,963 participants without fractures at baseline in the UK Biobank. Cox proportional hazard models were used to estimate the associations of metabolomic biomarkers measured by NMR technology with the risk of all fractures and hip fracture. We used principal component analysis (PCA) to obtain uncorrelated principal components (PC), which were further used to estimate the associations of each PC with BMD, all fractures, and hip fracture separately.

RESULTS

During a median follow-up of 12.6 years, 3840 incidents of all fractures and 666 incidents of hip fracture were documented. Ninety-four of the 143 metabolomic biomarkers were significantly associated with incident all fractures, and 81 were significantly associated with incident hip fracture. The very low-density lipoprotein (VLDL) subclasses in different lipid constituents were associated with increased BMD at multiple sites, whereas high-density lipoprotein (HDL) subclasses were associated with decreased BMD. Higher concentrations of small (HR per SD increment: 0.92; 95 % CI: 0.88-0.97), medium (HR per SD increment: 0.91; 95 % CI: 0.88-0.94), and large (HR per SD increment: 0.93; 95 % CI: 0.90-0.96) low-density lipoprotein (LDL) particles were associated with a lower risk of all fractures. Similarly, higher VLDL subclasses (excluding very small VLDL particles) were associated with a lower risk of all fractures. Besides, higher levels of lipid constituents (including total lipids, cholesteryl esters, cholesterol, and free cholesterol) of very large and large HDL were associated with an increased risk of all fractures. PC1 (mainly contributed by lipid subclasses of LDL and VLDL), which explained the most variance of individual biomarkers, showed a negative association with the risk of all fractures (P = 7.80E-08). Similar associations were observed for hip fracture.

CONCLUSIONS

Higher levels of large and very large HDL were associated with an increased risk of fractures, whereas higher lipid subclasses of LDL and VLDL were associated with a lower risk of fracture. Higher levels of VLDL subclasses in different lipid constituents were associated with increased BMD at multiple sites, while higher level of HDL was associated with decreased BMD.

Decreased sirtuin 1 in type 2 diabetes patients with abnormal BMD

Introduction

Sirtuin 1, a class III histone deacetylase, plays a critical role in the pathophysiology of both diabetes mellitus and bone metabolism by promoting osteoblast differentiation and inhibiting osteoclast maturation. However, its exact impact on bone mineral density (BMD) and bone metabolism in type 2 diabetes mellitus (T2DM) remains unclear. This study investigates the relationship between Sirtuin 1 levels, BMD, and bone metabolism in newly diagnosed T2DM patients, specifically examining alterations in Sirtuin 1 levels in those with concomitant osteoporosis or osteopenia.

Methods

A total of 69 newly diagnosed T2DM patients and 82 control subjects with normal glucose tolerance (NGT) were enrolled. Serum Sirtuin 1 levels and bone turnover markers, including osteocalcin (OC), procollagen type 1 N-terminal propeptide (P1NP), and β-C-terminal telopeptide of type I collagen (β-CTX), were measured using enzyme-linked immunosorbent assay (ELISA). BMD was assessed via dual-energy X-ray absorptiometry (DXA). Comparisons of these parameters were made between the T2DM and NGT groups.

Results

T2DM patients were further categorized into a normal BMD group (DMn) and an osteopenia or osteoporosis group (DMo), and differences in Sirtuin 1 levels between these subgroups were analyzed. Risk factors for osteoporosis/osteopenia in T2DM patients were also evaluated. Serum Sirtuin 1 levels were found to be significantly diminished in the T2DM group relative to the control group (P < 0.05), with no significant differences in lumbar spine BMD, OC, 25(OH)D, and β-CTX between groups (P > 0.05). Osteoporosis incidence was higher in T2DM subjects compared to controls (34.8% vs. 18.3%, P = 0.026). Subgroup analysis revealed that SIRT1 levels in T2DM patients with osteoporosis or osteopenia exhibited a significant reduction compared to those with normal BMD (P < 0.05). Logistic regression indicated that Sirtuin 1, age, HDL-C, P1NP, and β-CTX were independent risk factors for osteoporosis in T2DM patients.

Discussion

In conclusion, decreased serum Sirtuin 1 levels are associated with bone turnover markers in T2DM patients and may serve as an independent risk factor and potential biomarker for diagnosing bone metabolism disorders in newly diagnosed T2DM patients.

Lipid metabolites are associated with the risk of osteoporotic fractures

We conducted this cross-sectional study to investigate the independent associations between lipid metabolites and osteoporotic fractures among participants aged 40-69 years from the UK Biobank. Serum lipid, lipoprotein levels and nuclear magnetic resonance (NMR) based metabolic biomarkers were measured at the baseline. We conducted multivariable logistic analyses to investigate potential independent associations between concentrations of lipid metabolites and osteoporotic fractures in both men and women. The odds ratios (ORs) for lipid metabolites were calculated based on their lowest tertile. Over a median follow-up period of 15 years, a total of 978 men and 4515 women were diagnosed with osteoporosis, whereas 138 men and 327 women encountered incident fractures. Statistically significant disparities were identified in NMR-based metabolic biomarkers among men and women with incident fractures compared to those without. Out of the 144 distinct lipid metabolites known, 35 exhibited significant associations with incident fractures in patients diagnosed with osteoporosis. Following the adjustment for confounding factors, degree of unsaturation (p = 0.0066) and docosahexaenoic acids (p = 0.0011) in male patients increased the risk of incident fractures. And high level of different metabolites of HDL (p = 0.0153), 3-Hydroxybutyrate (p = 0.0012) and Sphingomyelins (p = 0.0036) decreased the risk of incident fractures in female patients. This outcome indicates that these identified lipid metabolites may potentially have unique roles in independently contributing to the occurrence of osteoporotic fractures.

Novel Associations of Dyslipidaemia with Vitamin D and Bone Metabolism in Elderly Patients with Diabetes: A Cross-Sectional Study

Objective

Little is known about whether diabetic dyslipidaemia contributes to increased bone fragility in patients with diabetes. This study aimed to explore the potential effects of dyslipidaemia on vitamin D and bone metabolism in elderly subjects with type 2 diabetes (T2D).

Methods

A total of 1479 male patients and 1356 female patients 50 years or older with T2D were included in Shanghai, China. Lipid profiles, 25-hydroxyvitamin D (25(OH)D), serum procollagen type I N-terminal propeptide (P1NP), β-C-terminal telopeptide (β-CTX) and other parameters were measured. Principal component regression (PCR) and mediation analysis were used to estimate the associations of lipid profile, 25(OH)D and bone turnover levels.

Results

Female patients presented with higher blood lipids, lower 25(OH)D, and higher P1NP and β-CTX levels than male patients with T2D. TC was associated with P1NP in males and females (β=0.056, P<0.05; β=0.095, P<0.01, respectively), and 25(OH)D fully mediated the associations in males and mediated approximately 17.89% of the effects in females. LDL-C was associated with P1NP in males and females (β=0.072 and 0.105 respectively, all P<0.01), and 25(OH)D mediated the relationships approximately 20.83% in males and 14.29% in females. TG was negatively associated with P1NP (in males, β= -0.063, P<0.05; in females, β= -0.100, P<0.01) and β-CTX (in males, β= -0.108; in females, β= -0.128, all P<0.01) independent of 25(OH)D, while HDL-C was not associated with P1NP or β-CTX in diabetic patients.

Conclusion

Hypercholesterolemia and hypertriglyceridaemia might affect bone metabolism by distinguishing pathways in diabetes patients. Ameliorating lipid control in elderly diabetes patients, especially female patients, will benefit both vitamin D and bone metabolism.

Influence of Cholesterol on the Regulation of Osteoblast Function

Bone is a dynamic tissue composed of cells, an extracellular matrix, and mineralized portion. Osteoblasts are responsible for proper bone formation and remodeling, and function. These processes are endergonic and require cellular energy in the form of adenosine triphosphate (ATP), which is derived from various sources such as glucose, fatty acids, and amino acids. However, other lipids such as cholesterol have also been found to play a critical role in bone homeostasis and can also contribute to the overall bioenergetic capacity of osteoblasts. In addition, several epidemiological studies have found a link between elevated cholesterol, cardiovascular disease, an enhanced risk of osteoporosis, and increased bone metastasis in cancer patients. This review focuses on how cholesterol, its derivatives, and cholesterol-lowering medications (statins) regulate osteoblast function and bone formation. It also highlights the molecular mechanisms underlying the cholesterol-osteoblast crosstalk.

Total Cholesterol Variability and the Risk of Osteoporotic Fractures: A Nationwide Population-Based Cohort Study

Several risk factors for osteoporotic fractures have been identified but reports of the association of lipid parameters with the occurrence of osteoporotic fractures have been limited. We aimed to examine whether serum total cholesterol (TC) variability is associated with osteoporotic fractures. The study included 3,00,326 subjects who had undergone three or more health examinations between 2003 and 2008. The primary endpoint was the incidence of osteoporotic fractures, including vertebral, hip, distal radius, and humerus fractures. TC variability was evaluated based on the following three parameters: coefficient of variation (CV), standard deviation (SD), and variability independent of the mean (VIM). A total of 29,044 osteoporotic fracture events (9.67%) were identified during a median of 11.6 years of follow-up. The risk of osteoporotic fractures in the highest quartile was significantly higher compared with the lowest quartile according to the three indices of TC variability with adjusted hazard ratios (HR) and 95% confidence intervals (CI) as follows: CV (HR 1.11, 95% CI [1.08–1.15]), SD (HR 1.07, 95% CI [1.04–1.11]) and VIM (HR 1.07, 95% CI [1.04–1.11]). The Kaplan–Meier curves showed a significantly positive relationship between the higher quartile of TC variability and overall osteoporotic fractures. The association remained significant in subgroup analyses of vertebral and hip fractures, regardless of the indices of TC variability. Our study showed that visit-to-visit TC variability was found to be associated with osteoporotic fracture risk. Maintaining TC levels stable may help attenuate the osteoporotic fracture risk in the future.

Metabolomic patterns, redox-related genes and metals, and bone fragility endpoints in the Hortega Study

BACKGROUND

The potential joint influence of metabolites on bone fragility has been rarely evaluated. We assessed the association of plasma metabolic patterns with bone fragility endpoints (primarily, incident osteoporosis-related bone fractures, and, secondarily, bone mineral density BMD) in the Hortega Study participants. Redox balance plays a key role in bone metabolism. We also assessed differential associations in participant subgroups by redox-related metal exposure levels and candidate genetic variants.

MATERIAL AND METHODS

In 467 participants older than 50 years from the Hortega Study, a representative sample from a region in Spain, we estimated metabolic principal components (mPC) for 54 plasma metabolites from NMR-spectrometry. Metals biomarkers were measured in plasma by AAS and in urine by HPLC-ICPMS. Redox-related SNPs (N = 341) were measured by oligo-ligation assay.

RESULTS

The prospective association with incident bone fractures was inverse for mPC1 (non-essential and essential amino acids, including branched-chain, and bacterial co-metabolites, including isobutyrate, trimethylamines and phenylpropionate, versus fatty acids and VLDL) and mPC4 (HDL), but positive for mPC2 (essential amino acids, including aromatic, and bacterial co-metabolites, including isopropanol and methanol). Findings from BMD models were consistent. Participants with decreased selenium and increased antimony, arsenic and, suggestively, cadmium exposures showed higher mPC2-associated bone fractures risk. Genetic variants annotated to 19 genes, with the strongest evidence for NCF4, NOX4 and XDH, showed differential metabolic-related bone fractures risk.

CONCLUSIONS

Metabolic patterns reflecting amino acids, microbiota co-metabolism and lipid metabolism were associated with bone fragility endpoints. Carriers of redox-related variants may benefit from metabolic interventions to prevent the consequences of bone fragility depending on their antimony, arsenic, selenium, and, possibly, cadmium, exposure levels.

Associations between bone mineral density and subclinical peripheral arterial disease in elderly men with type 2 diabetes mellitus

The association between peripheral arterial disease (PAD) and osteoporosis in elderly men with type 2 diabetes mellitus (T2DM) remains unclear. We demonstrated the association between subclinical PAD and decreased total hip bone mineral density (BMD) in men aged ≥ 55 years with T2DM, providing clinical clues for the early detection of decreased bone density in total hip.

PURPOSE

To investigate the association between subclinical peripheral arterial disease (PAD) and bone mineral density (BMD) at total hip, femoral neck, and lumbar spine (L_1-4) in elderly men with type 2 diabetes mellitus (T2DM).

METHODS

We identified 2,466 patients with confirmed diabetes in this retrospective cross-sectional study. A total of 272 men aged ≥ 55 years with T2DM (50 with subclinical PAD and 222 without PAD) were analyzed. Partial correlation analysis was conducted to explore the associations between ankle-brachial index (ABI) and BMD. Multivariate logistic regression analysis was performed to analyze the contributor for low bone density (T-score <  - 1.0).

RESULTS

Patients with T2DM and subclinical PAD (ABI ≤ 0.9) had significantly lower total hip BMD and T-score (BMD, 0.87 ± 0.14 vs. 0.92 ± 0.15 g/cm², P = 0.014; T-score, -1.30 [-1.70 to -0.45] vs. -0.80 [-1.40 to 0.00], P = 0.009) than those in the control group. The partial correlation analyses indicated that ABI significantly correlated with the total hip T-score (adjusted r = 0.166, P = 0.009). The logistic regression analysis indicated that subclinical PAD was an independent risk factor for the risk of decreased bone density in total hip (adjusted odds ratio [95% CI]: 8.933 [1.075-74.222], P = 0.043).  CONCLUSION: Subclinical PAD (ABI ≤ 0.9) could be used as a risk factor for decreased total hip BMD in men aged ≥ 55 years with T2DM, which provides clinical clues for the early detection of low bone density in total hip in such populations.

Safety of ezetimibe in lipid-lowering treatment: systematic review and meta-analysis of randomised controlled trials and cohort studies

OBJECTIVE

To determine the harms of ezetimibe in people who need lipid-lowering treatment.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Randomised controlled trials and cohort studies.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies comparing ezetimibe with placebo, standard care, or other lipid-lowering agents in people who need lipid-lowering treatment with a follow-up duration of at least six months (or 24 weeks). The relative effects for potential harms of ezetimibe were pooled by use of random effect pairwise meta-analyses for randomised controlled trials and the evidence from observational studies was narratively summarised. The certainty of evidence was assessed using the Grading of Recommendation Assessment, Development, and Evaluation.

RESULTS

48 randomised controlled trials with 28 444 participants (median follow-up 34 weeks, range 24-312 weeks) and four observational studies with 1667 participants (median follow-up 282 weeks, range 72-400 weeks) were included. The meta-analyses of randomised trials showed moderate to high certainty that ezetimibe was not associated with cancer (relative risk 1.01; 95% confidence interval 0.92 to 1.11), fractures (0.90; 0.74 to 1.10), discontinuation due to any adverse event (0.87; 0.74 to 1.03), gastrointestinal adverse events leading to discontinuation (1.34; 0.58 to 3.08), myalgia or muscular pain leading to discontinuation (0.82; 0.51 to 1.33), neurocognitive events (1.48; 0.58 to 3.81), or new-onset diabetes (0.88; 0.61 to 1.28). The narrative analysis of observational studies provided consistent findings. No credible subgroup effects were identified for the harm outcomes, including shorter versus longer follow-up duration of trials.

CONCLUSIONS

Ezetimibe results in little to no difference in adverse events or other undesirable effects compared with placebo, usual care or other lipid-lowering agents.

REVIEW REGISTRATION

PROSPERO CRD42020187437.

The levels of 25-hydroxy vitamin D, parathyroid hormone, calcitonin and lipid profiles in patients with calcaneal spur

Objectives

The aim of this study was to investigate the 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), and calcitonin levels and lipid profiles in patients with calcaneal spurs.

Patients and methods

Between March 2018 and June 2019, a total of 50 patients (30 males, 20 females; mean age: 39.8±8.1 years; range, 24 to 54 years) admitted to our clinic with heel pain and diagnosed with heel spurs based on radiographic images were included. The control group consisted of 50 age- and sex-matched healthy volunteers (32 males, 18 females; mean age: 35.7±9.6 years; range, 20 to 56 years). Blood samples were collected from all participants. Total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride, phosphate, and calcium levels were measured using the colorimetric method. The PTH and 25(OH)D levels were measured using the chemiluminescent microparticle immunoassay. Calcitonin levels were detected using the chemiluminescent immunometric assay.

Results

In the patients with calcaneal spurs, 25(OH)D and HDL-C levels were significantly lower (p<0.001), while LDL-C, triglyceride, and PTH levels were significantly higher (p<0.05, p<0.002 and p<0.001, respectively). There was no significant difference in the calcium, phosphate, body mass index, and calcitonin levels between the groups.

Conclusion

Our study results suggest that calcaneal spur formation is associated not only with weight-related pressure, but also with lipid levels and hormonal alterations involved in calcium metabolism. Based on these findings, hormonal alterations and lipids should be considered in patients with calcaneal spurs.

Effects of hyperlipidemia on trabecular and cortical structures of the mandible

OBJECTIVES

To evaluate the mandibular bone structure of patients with hyperlipidemia by fractal dimension (FD) analysis and panoramic radiomorphometric indices including mandibular cortical thickness measurement, panoramic mandibular index (PMI), mandibular cortical index (MCI) and to compare with the healthy group.

METHODS

In total, 60 panoramic radiographs were included, including panoramic radiographs of 30 individuals with hyperlipidemia and 30 individuals with systemically healthy. FD analysis in the mandibular condyle, angle of the mandible, the distal side of the second premolar and anterior to mental foramen, PMI, MCI, and mandibular cortical thickness measurements were evaluated on radiographs. Independent samples t-test was used for differences between healthy and hyperlipidemia groups with regard to age and PMI. Repeated measurement of variance with one within and one between factors in the comparison of four regions and two groups in terms of FD and cortical thickness measurements. Following this analysis, significant differences were detected by post-hoc Sidak test. Fisher-Freeman-Halton analysis was applied to determine the relationship between categorical variables.

RESULTS

FD values of the hyperlipidemic patients were found to be lower than the healthy group. Between the hyperlipidemic and healthy groups, there was a difference in the angle of the mandible FD values (p = 0.020). There were no differences in the cortical thickness measurements and PMI between the groups (p > 0.05). There was a difference in MCI values between the groups (p < 0.05).

CONCLUSION

The trabecular structure of the angle of the mandible and the cortical bone structure of the mandible were found to be negatively affected by hyperlipidemia.

Lipid metabolism within the bone micro-environment is closely associated with bone metabolism in physiological and pathophysiological stages

Recent advances in society have resulted in the emergence of both hyperlipidemia and obesity as life-threatening conditions in people with implications for various types of diseases, such as cardiovascular diseases and cancer. This is further complicated by a global rise in the aging population, especially menopausal women, who mostly suffer from overweight and bone loss simultaneously. Interestingly, clinical observations in these women suggest that osteoarthritis may be linked to a higher body mass index (BMI), which has led many to believe that there may be some degree of bone dysfunction associated with conditions such as obesity. It is also common practice in many outpatient settings to encourage patients to control their BMI and lose weight in an attempt to mitigate mechanical stress and thus reduce bone pain and joint dysfunction. Together, studies show that bone is not only a mechanical organ but also a critical component of metabolism, and various endocrine functions, such as calcium metabolism. Numerous studies have demonstrated a relationship between metabolic dysfunction in bone and abnormal lipid metabolism. Previous studies have also regarded obesity as a metabolic disorder. However, the relationship between lipid metabolism and bone metabolism has not been fully elucidated. In this narrative review, the data describing the close relationship between bone and lipid metabolism was summarized and the impact on both the normal physiology and pathophysiology of these tissues was discussed at both the molecular and cellular levels.

The Positive Relationship Between the Low-Density Lipoprotein Cholesterol/Apoprotein B Ratio and Bone Turnover Markers in Patients With Type 2 Diabetes

BACKGROUND

Dyslipidemia may contribute to low bone turnover in patients with type 2 diabetes (T2D) through mediating oxidative stress and atherosclerosis. The low-density lipoprotein cholesterol/apoprotein B (LDL-C/Apo B) ratio is a surrogate marker of small and density low-density lipoprotein cholesterol (sd-LDL-C), a most harmful group of LDL-Cs. The present study aimed to investigate the association between the LDL-C/Apo B ratio and bone turnover in patients with T2D.

METHODS

This study was a cross-sectional study enrolled patients with T2D from January 2021 to December 2021. Each participant was assessed for lipid profiles, bone turnover markers (BTMs), lumbar spine (L1-L4) and hip dual-energy X-ray absorptiometry (DXA) scans. Osteoporosis was diagnosed as a T-score lower than or equal to -2.5 at the spine or hip.

RESULTS

A total of 335 patients with T2D were enrolled in the study, and the LDL-C/Apo B ratio ranged from 0.78 to 4.00. Along with the LDL-C/Apo B ratio tertile ascending, osteocalcin (OC), C-terminal telopeptide (CTx) and N-terminal propeptide of type-I procollagen (PINP) levels gradually increased (all p < 0.05). There were no differences in lumbar spine and hip T-score, proportion of osteoporosis (all p > 0.05) among the three subgroups. The LDL-C/Apo B ratio was positively correlated with lnOC (r = 0.244, p < 0.001), lnCTx (r = 0.226, p < 0.01) and lnPINP (r = 0.211, p < 0.001). These significant positive correlations persisted even when divided into male and female subgroups. Furthermore, three multiple linear regression analyses were constructed to investigate the independent association of the LDL-C/Apo B ratio with the BTMs levels. After adjusting for other clinical parameters, the LDL-C/Apo B ratio was still significantly associated with OC level (β = 0.199, t = 3.348, p < 0.01), CTx level (β = 0.238, t = 4.084, p < 0.001) and PINP level (β = 0.162, t = 2.741, p < 0.01).

CONCLUSION

The LDL-C/Apo B ratio was significantly and positively associated with BTMs in patients with T2D. In clinical practice, more attention should be paid to the patients with T2D whose LDL-C/Apo B ratio is relatively low for the purpose of maintaining bone health.

Low dose hydrophilic statins are the preferred agents for females at risk of osteoporosis

Objectives

The correlation between atherosclerosis and osteoporosis, independent of age, is clear. Multifactorial co-dependence between bone mineral density (BMD) and statin dose has been proposed. It is hypothesised that inhibition of the synthesis of cholesterol will also inhibit the synthesis of sex hormones and Vitamin D, negatively affecting BMD. This study aims to evaluate hydrophilic and non-hydrophilic statins effect on osteoporosis and analyse any possible superiority of one agent over the other within the group.

Methods

We identified 538 caucasian females who had a DEXA scan performed between 2002 and 2016 (age 60-89) in one DEXA center in Mid-West Ireland. A DEXA T-score results were analysed in the current study. Two hundred fifty females were not on statin therapy, and 323 females were on statin therapy. Females on therapy were separated into the atorvastatin group (N = 190), rosuvastatin group (N = 97), and pravastatin group (N = 36), comprising low dose and high dose groups. All anonymised data were analysed with SPSS statistical. To test the hypothesis that lower bone density is associated with high dose statins, an independent sample t-test was performed. The one-way between-groups ANOVA test was used to test the hypothesis that the BMD level depended on the statin's potency.

Results

Statin-naïve females have a statistically higher bone mineral density in the lumbar spine, t (538) = 3.42, p < 0.05 and in hip t (538) = 4.99, p < 0.05 than females on statin therapy. There was a significant difference in patient's age between the group, and no significant correlation was found between the patient's age and type of statin or bone density. In the atorvastatin group statistically, significant results were obtained both for spine and hip bone mineral density, t (188) = -5.61, p < 0.05 and t (188) = -3.62, p < 0.05, respectively. In the rosuvastatin group, statistically, a significant result was noted for bone mineral density of hip t (95) = -3.52, p < 0.05. This demonstrates a dose-dependency between bone mineral density and the dose of the statin. The independent between-group ANOVA yielded a statistically significant effect, F (2, 59) = 6.69, p < 0.05, η2 = 0.21 in the spine. Thus, patients on lipophilic statins had statistically lower BMD than females on hydrophilic statins. Multilinear regression analysis identified that age is not a statistically significant contributor in our analysis; however, the trend of decrease in bone mineral density with women's age is acknowledged by authors.

Conclusions

The study results support the theory that bone mineral density decreases with an increase in a statin dose, and hydrophilic statins, like pravastatin, have a better metabolic profile in the lumbar spine than lipophilic agents.

Association of hip fractures with cardiometabolic-renal risk factors in Southern Chinese patients with type 2 diabetes - the Hong Kong Diabetes Register

INTRODUCTION

Diabetes and bone health are closely related. We examined the incidence and risk factors of hip fractures in Chinese patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

In this prospective cohort, we consecutively enrolled 22,325 adults with T2D above the age of 40 years in the Hong Kong Diabetes Register between 1994 and 2015 with crude hip fracture incidence rate censored in 2017.

RESULTS

At baseline, the mean age of this cohort was 60.9 ± 10.5 years (mean duration of diabetes 6 years, 52.4% male). During a mean ± standard deviation (SD) follow-up period of 8.7 ± 5.2 years with 193,553 person-years, 603 patients were hospitalized due to hip fractures with an incidence (95% confidence interval, CI) of 315.1 (290.4-341.3) per 100,000 person-years. On multivariable analysis with competing death risk adjusted, the independent hazard ratios (95% CI) for hip fractures in T2D were 2.01 (1.61-2.51) for female sex, 1.08 (1.07-1.09) for age, 0.93 (0.90-0.95) for body mass index, 1.52 (1.25-1.85) for albuminuria and 1.12 (1.02-1.23) for low density lipoprotein-cholesterol. In men, the 30-day, 1-year and 5-year post-hip fracture mortality rate (95% CI) were 5.8 (2.4-9.1) %, 29.2 (22.3-35.5) % and 65.9 (57.3-72.8) % respectively. The corresponding rates in women were 3.4 (1.6-5.1) %, 18.6 (14.7-22.4) %, and 46.8 (40.9-52.1) %.

CONCLUSIONS

Southern Chinese patients with T2D have a high risk of hip fracture associated with suboptimal cardiometabolic-renal risk factors and a high post-fracture mortality rate. The effects of improving modifiable risk factors on bone health warrants further evaluation.

Effect of Multimorbidity on Fragility Fractures in Community-Dwelling Older Adults: Shimane CoHRE Study

Fragility fractures (FFxs), which are a common musculoskeletal injury in older adults, is associated with an increased frequency of falls. Both FFxs and falls may result from drugs, habits, and co-occurring diseases. We aimed to evaluate the effects of various diseases on the risk of FFx. This retrospective study included 1420 individuals aged ≥60 years. We evaluated the history of clinical FFx and diseases using a detailed questionnaire and a health examination. The risk of comorbidities was assessed using the Age-Adjusted Charlson Comorbidity (AAC) Index. We performed binary logistic regression analysis to determine the risk of FFx and falls after adjusting for covariates. In elderly men, the incidence of FFx positively correlated with rheumatoid arthritis and parent's hip fracture. For elderly women, the incidence of FFx positively correlated with rheumatoid arthritis and antihypertensive drugs but was inversely associated with dyslipidemia and antilipidemic drugs. The FFX risk of older adults with an AAC Index ≥6 was higher than those with an AAC Index of 1-3. In addition, the AAC Index and falls were independently and strongly associated with a higher risk of FFx. Taken together, multimorbidity increases the risk of clinical FFx independent of falls in the community-dwelling elderly population.

Association Between Bone Mineral Density and Lipid Profile in Chinese Women

Purpose

Atherosclerotic cardiovascular disease may share the risk factors for low bone mineral density (BMD), one of which is dyslipidemia. The association between serum cholesterol and BMD remains controversial. Thus, the correlation between serum lipids and BMD in women was explored in the current study.

Materials and Methods

This cross-sectional study included 1116 Chinese female participants. Serum samples were collected to evaluate total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and other laboratory markers. Dual-energy X-ray absorptiometry was used to assess lumbar spine, femoral neck, and total hip BMD.

Results

In the postmenopausal women, a non-linear relationship was detected between TC, LDL-C, HDL-C, and lumbar spine BMD. Using segmented linear regression, the inflection points were 5.86 mmol/L, 3.52 mmol/L, and 2.37 mmol/L, respectively. To the left of the inflection point, the higher the serum lipid level, the lower the value for lumbar spine BMD. To the right of the inflection point, the higher the serum level of TC and LDL-C, the higher the value for lumbar spine BMD. In the premenopausal women, the association between HDL-C and femoral neck BMD was non-linear. In addition, LDL-C had a positive association with BMD of the femoral neck and HDL-C had an inverse association with BMD of the femoral neck in postmenopausal women.

Conclusion

In postmenopausal women, the relationship between TC, LDL-C, HDL-C, and lumbar spine BMD was non-linear. TC, LDL-C, and HDL-C were negatively associated with lumbar spine BMD when the values were less than 5.86 mmol/L, 3.52 mmol/L, and 2.37 mmol/L, respectively. The mechanisms of the association were unclear, and further research is warranted to clarify the relationship.

Effects of lipid metabolism on mouse incisor dentinogenesis

Tooth formation can be affected by various factors, such as oral disease, drug administration, and systemic illness, as well as internal conditions including dentin formation. Dyslipidemia is an important lifestyle disease, though the relationship of aberrant lipid metabolism with tooth formation has not been clarified. This study was performed to examine the effects of dyslipidemia on tooth formation and tooth development. Dyslipidemia was induced in mice by giving a high-fat diet (HFD) for 12 weeks. Additionally, LDL receptor-deficient (Ldlr^−/−) strain mice were used to analyze the effects of dyslipidemia and lipid metabolism in greater detail. In the HFD-fed mice, incisor elongation was decreased and pulp was significantly narrowed, while histological findings revealed disappearance of predentin. In Ldlr^−/− mice fed regular chow, incisor elongation showed a decreasing trend and pulp a narrowing trend, while predentin changes were unclear. Serum lipid levels were increased in the HFD-fed wild-type (WT) mice, while Ldlr^−/− mice given the HFD showed the greatest increase. These results show important effects of lipid metabolism, especially via the LDL receptor, on tooth homeostasis maintenance. In addition, they suggest a different mechanism for WT and Ldlr^−/− mice, though the LDL receptor pathway may not be the only factor involved.

Dual Effects of Lipid Metabolism on Osteoblast Function

The skeleton is a dynamic and metabolically active organ with the capacity to influence whole body metabolism. This newly recognized function has propagated interest in the connection between bone health and metabolic dysfunction. Osteoblasts, the specialized mesenchymal cells responsible for the production of bone matrix and mineralization, rely on multiple fuel sources. The utilization of glucose by osteoblasts has long been a focus of research, however, lipids and their derivatives, are increasingly recognized as a vital energy source. Osteoblasts possess the necessary receptors and catabolic enzymes for internalization and utilization of circulating lipids. Disruption of these processes can impair osteoblast function, resulting in skeletal deficits while simultaneously altering whole body lipid homeostasis. This article provides an overview of the metabolism of postprandial and stored lipids and the osteoblast's ability to acquire and utilize these molecules. We focus on the requirement for fatty acid oxidation and the pathways regulating this function as well as the negative impact of dyslipidemia on the osteoblast and skeletal health. These findings provide key insights into the nuances of lipid metabolism in influencing skeletal homeostasis which are critical to appreciate the extent of the osteoblast's role in metabolic homeostasis.

Lipid Profile and Risk of Bone Fracture: A Systematic Review and Meta-Analysis of Observational Studies

Purpose: Earlier studies have linked lipid profile to osteoporotic fractures; however, to our knowledge, no study had summarized available data on this relationship. We aimed to summarize the current evidence on the association between lipid profile and bone fractures. Material and Methods: A systematic search of PubMed and Scopus was done to find relevant published studies until March 2018. To combine effect sizes, we applied fixed- or random-effects analysis, where appropriate. Cochran's Q test and I² were used to assess between-study heterogeneity. Results: Overall, 11 studies (seven prospective, three cross-sectional and one case-control studies) were included in the current systematic review. Out of them, 10 studies with a total sample size of 60,484 individuals, aged 25 years or more, were used in the meta-analysis. The results showed that total cholesterol concentration was positively associated with risk of bone fracture; such that a 50-mg/dl increase in plasma level of TC was associated with 15% greater odds of bone fracture (combined effect size: 1.15, 95% CI: 1.02-1.30, P = .02). Furthermore, we found that individuals with a decreased level of HDL (<40 mg/dl) had a lower risk of bone fracture compared with those with a normal level (≥40 mg/dl) (combined effect size: 0.82, 95% CI: 0.71-0.96, P = .01). No significant association was found between plasma level of TG and LDL with the risk of bone fractures either in prospective or cross-sectional studies. Conclusions: We found that plasma levels of total cholesterol were positively associated with bone fractures. In addition, decreased levels of HDL were associated with an increased risk of osteoporotic fractures. Abbreviations: TG: triglycerides, TC: total cholesterol, HDL: high-density lipoprotein, LDL: low-density lipoprotein, OR: odds ratio, RR: relative risk, HR: hazard ratio, DXA: dual-energy X-ray absorptiometry, ICD: International Classification of Diseases, SD: standard deviation.

Causal link between lipid profile and bone mineral density: A Mendelian randomization study

The level of serum lipids is associated with bone mineral density (BMD), an important skeletal trait. Yet the causality has not been determined. Here we performed a Mendelian randomization (MR) analysis to test potential causal links between BMD and lipid profile, i.e., low-density lipoprotein cholesterol (LDC-c), total cholesterol (TC), triglyceride (TG) and high-density lipoprotein cholesterol (HDL-c). We observed causal effect of LDL-c, TC and TG to BMD, and reversely the effect of BMD to HDL-c. We further explored the effect of body mass index (BMI) in these causalities and found that the effect of LDL-c, TC and TG to BMD is independent of BMI. Our findings provided useful information in the clinical relevance of blood lipids on BMD variation and osteoporosis risk.

A community-based study of the relationship between calcaneal bone mineral density and systemic parameters of blood glucose and lipids

Osteoporosis (OP) is a disease characterized by decreased bone mineral density (BMD) and an increased risk of osteoporotic fractures. Nutritional factors (including glucose and fats lipids), have been implicated in OP.We hypothesized that the levels of blood glucose and lipids could be biomarkers for predicting the risk of OP. To test this hypothesis, we evaluated the potential relationship between BMD and levels of blood glucose and lipids via a community-based study in China.This was a community-based cross-section analysis, and a total of 8584 cases were investigated. The BMD of the left calcaneus was measured using an ultrasonic bone densitometer. The levels of blood glucose (fasting blood glucose [FBG], 2-h blood glucose [2hBG], and glycosylated hemoglobin [HbAlc]), and lipids (triglyceride [TG], total cholesterol [TC], low-density lipoprotein cholesterol [LDL-C], and high-density lipoprotein cholesterol [HDL-C]) were measured and analyzed.In our study population, the levels of FBG, 2hBG, HbAlc, TC, LDL-C and HDL-C were higher in the OP group than in the low bone density and the normal bone density groups, while the levels of HbAlc, TC, and LDL-C in the low bone density group were higher than those in the normal bone density group. In males, the level of blood LDL-C in the low bone density group was higher than that in the normal bone density group. In postmenopausal subjects, the levels of FBG, 2hBG and HbA1C were higher than those in the normal bone density groups, and the level of HbA1C in the low bone density group was higher than that in the normal bone density group. Pearson linear trend analysis demonstrated that BMD was positively associated with TC and LDL-C in males and negatively associated with FBG, 2hBG and HbA1C in postmenopausal females. Moreover, logistic analysis showed that BMD was correlated with TC in premenopausal females and HbA1C in postmenopausal females.OP is generally associated with abnormal levels of blood glucose and/or lipids; nevertheless, the relationship between OP and abnormal levels of blood glucose and/or lipids is complicate and different subpopulations may have different susceptibilities. Therefore, further detailed studies are warranted.

Modulation of Bone and Marrow Niche by Cholesterol

Bone is a complex tissue composing of mineralized bone, bone cells, hematopoietic cells, marrow adipocytes, and supportive stromal cells. The homeostasis of bone and marrow niche is dynamically regulated by nutrients. The positive correlation between cardiovascular disease and osteoporosis risk suggests a close relationship between hyperlipidemia and/or hypercholesterolemia and the bone metabolism. Cholesterol and its metabolites influence the bone homeostasis through modulating the differentiation and activation of osteoblasts and osteoclasts. The effects of cholesterol on hematopoietic stem cells, including proliferation, migration, and differentiation, are also well-documented and further relate to atherosclerotic lesions. Correlation between circulating cholesterol and bone marrow adipocytes remains elusive, which seems opposite to its effects on osteoblasts. Epidemiological evidence has demonstrated that cholesterol deteriorates or benefits bone metabolism depending on the types, such as low-density lipoprotein (LDL) or high-density lipoprotein (HDL) cholesterol. In this review, we will summarize the latest progress of how cholesterol regulates bone metabolism and bone marrow microenvironment, including the hematopoiesis and marrow adiposity. Elucidation of these association and factors is of great importance in developing therapeutic options for bone related diseases under hypercholesterolemic conditions.

Intraoperative hemorrhage in revision total hip arthroplasty: a retrospective single-center study

PURPOSE

The amount of intraoperative hemorrhages and factors associated with hemorrhages and transfusions during revision total hip arthroplasty (reTHA) have not been identified for Japanese patients. We aimed to clarify the amount of intraoperative hemorrhages, and to elucidate the factors associated with hemorrhages and transfusions during reTHA in Japanese patients.

METHODS

We retrospectively reviewed patients who underwent reTHA (n = 48) and primary total hip arthroplasty (pTHA) (n = 615) in a single hospital and extracted data regarding hemorrhage, transfusion, patient comorbidities, and surgical anesthesia. We defined massive blood loss (MBL) as a hemorrhage comprising more than half of the circulating blood volume within 3 h. The odds ratio (OR) and 95% confidence interval (CI) were estimated using a multivariate logistic regression analysis.

RESULTS

There was a significant difference in hemorrhages between reTHA and pTHA patients (1790 g versus 625 g; p < 0.001). Among patients with reTHA, MBL was significantly associated with younger age (OR 0.91; 95% CI 0.84-1.00; p = 0.04) and lower body mass index (BMI) (OR 0.69; 95% CI 0.53-0.91; p = 0.01). Although not significant, the incidence of MBL tended to be higher for patients with hyperlipidemia (OR 4.88; 95% CI 0.99-24.1; p = 0.051). Furthermore, the need for allogeneic transfusion was significantly associated with the number of prepared autologous blood packs (OR 0.15; 95% CI 0.07-0.55; p = 0.002).

CONCLUSION

Although this study was limited by its small population and a possibility of underestimating the hemorrhage, hemorrhages in reTHA patients was two times greater than that in pTHA patients. Younger age and lower BMI increased the risk of MBL in reTHA. Preparing autologous blood decreased the risk of intraoperative allogeneic transfusion.

Lipoprotein(a) plasma levels, bone mineral density and risk of hip fracture: a post hoc analysis of the Women's Health Initiative, USA

OBJECTIVES

Elevated Lipoprotein(a) (Lp[a]) is a well-known risk factor for cardiovascular disease. However, its roles in bone metabolism and fracture risk are unclear. We therefore investigated whether plasma Lp(a) levels were associated with bone mineral density (BMD) and incident hip fractures in a large cohort of postmenopausal women.

DESIGN

Post hoc analysis of data from the Women's Health Initiative (WHI), USA.

SETTING

40 clinical centres in the USA.

PARTICIPANTS

The current analytical cohort consisted of 9698 white, postmenopausal women enrolled in the WHI, a national prospective study investigating determinants of chronic diseases including heart disease, breast and colorectal cancers and osteoporotic fractures among postmenopausal women. Recruitment for WHI took place from 1 October 1993 to 31 December 1998.

EXPOSURES

Plasma Lp(a) levels were measured at baseline.

OUTCOME MEASURES

Incident hip fractures were ascertained annually and confirmed by medical records with follow-up through 29 August 2014. BMD at the femoral neck was measured by dual X-ray absorptiometry in a subset of participants at baseline.

STATISTICAL ANALYSES

Cox proportional hazards and logistic regression models were used to evaluate associations of quartiles of plasma Lp(a) levels with hip fracture events and hip BMD T-score, respectively.

RESULTS

During a mean follow-up of 13.8 years, 454 incident cases of hip fracture were observed. In analyses adjusting for confounding variables including age, body mass index, history of hysterectomy, smoking, physical activity, diabetes mellitus, general health status, cardiovascular disease, use of menopausal hormone therapy, use of bisphosphonates, calcitonin or selective-oestrogen receptor modulators, baseline dietary and supplemental calcium and vitamin D intake and history of fracture, no significant association of plasma Lp(a) levels with low hip BMD T-score or hip fracture risk was detected.

CONCLUSIONS

These findings suggest that plasma Lp(a) levels are not related to hip BMD T-score or hip fracture events in postmenopausal women.

TRIAL REGISTRATION NUMBER

NCT00000611; Post-results.

Osteoporosis is inversely associated with arterial stiffness in the elderly: An investigation using the Osteoporosis Self-assessment Tool for Asians index in an elderly Chinese cohort

Although the association of arterial stiffness and osteoporosis has been reported, the relation of arterial stiffness with risk of osteoporosis and bone fracture is not established. The authors investigated the correlation between arterial stiffness (brachial-ankle pulse wave velocity [baPWV]), including a cutoff value, and risk of osteoporosis as assessed by the Osteoporosis Self-assessment Tool for Asia (OSTA) index in 129 elderly Chinese community-dwelling individuals (age 83.2 ± 12.8 years, 63 females). OSTA was negatively correlated with baPWV (r = -0.326, P = 0.023) after adjusting for confounding factors such as gender, body mass index, low-density lipoprotein, triglycerides, estimated glomerular filtration rate, absence or presence of diabetes, absence or presence of hypertension, and uric acid. baPWV was an independent factor for changes in OSTA (β = -0.001, P = 0.002). ROC curve analysis confirmed association between baPWV and OSTA index (AUC = 0.742 [CI: 0.660, 0.824]; P < 0.001) with a baPWV cutoff value of 1676 cm/s (sensitivity, 80.7%; specificity, 60%) for prediction of high OSTA index. The study showed a significant correlation between OSTA index and baPWV, suggesting a potential predictive value of baPWV in elderly patient at high risk of osteoporosis.

Western-type diet differentially modulates osteoblast, osteoclast, and lipoblast differentiation and activation in a background of APOE deficiency

During the past few years, considerable evidence has uncovered a strong relationship between fat and bone metabolism. Consequently, alterations in plasma lipid metabolic pathways strongly affect bone mass and quality. We recently showed that the deficiency of apolipoprotein A-1 (APOA1), a central regulator of high-density lipoprotein cholesterol (HDL-C) metabolism, results in reduced bone mass in C57BL/6 mice. It is documented that apolipoprotein E (APOE), a lipoprotein know for its atheroprotective functions and de novo biogenesis of HDL-C, is associated with the accumulation of fat in the liver and other organs and regulates bone mass in mice. We further studied the mechanism of APOE in bone metabolism using well-characterized APOE knockout mice. We found that bone mass was remarkably reduced in APOE deficient mice fed Western-type diet (WTD) compared to wild type counterparts. Static (microCT-based) and dynamic histomorphometry showed that the reduced bone mass in APOΕ^-/- mice is attributed to both decreased osteoblastic bone synthesis and elevated osteoclastic bone resorption. Interestingly, histologic analysis of femoral sections revealed a significant reduction in the number of bone marrow lipoblasts in APOΕ^-/- compared to wild type mice under WTD. Analyses of whole bone marrow cells obtained from femora of both animal groups showed that APOE null mice had significantly reduced levels of the osteoblastic (RUNX2 and Osterix) and lipoblastic (PPARγ and CEBPα) cardinal regulators. Additionally, the modulators of bone remodeling RANK, RANKL, and cathepsin K were greatly increased, while OPG and the OPG/RANKL ratio were remarkably decreased in APOΕ^-/- mice fed WTD, compared to their wild-type counterparts. These findings suggest that APOE deficiency challenged with WTD reduces osteoblastic and lipoblastic differentiation and activity, whereas it enhances osteoclastic function, ultimately resulting in reduced bone mass, in mice.

Association Between Bone Mineral Density, Bone Turnover Markers, and Serum Cholesterol Levels in Type 2 Diabetes

Purpose: The association between bone mineral density (BMD), bone turnover markers, and serum cholesterol in healthy population has already been proved. However, in patients with type 2 diabetes mellitus (T2D), it has not been adequately analyzed. In this study, we investigated the correlation between BMD, bone turnover markers, and serum cholesterol levels in people with T2D. Methods: We enrolled 1,040 men and 735 women with T2D from Zhongshan Hospital between October 2009 and January 2013. Their general condition, history of diseases and medication, serum markers, and BMD data were collected. We used logistic regression analysis to identify the association between serum cholesterol levels and BMD as well as bone turnover markers. Results: In multivariate regression analysis, we observed that in men with T2D, high high-density lipoprotein-cholesterol and total cholesterol levels were significantly associated with low total lumbar, femur neck, and total hip BMD, while low-density lipoprotein-cholesterol level was only inversely associated with total lumbar and femur neck BMD. Total cholesterol and low-density lipoprotein-cholesterol levels were also negatively associated with osteocalcin, procollagen type I N-terminal propeptide, and β-crosslaps. In women with T2D, high-density lipoprotein-cholesterol level was observed to be negatively correlated with total lumbar, femur neck, and total hip BMD, while total cholesterol and low-density lipoprotein-cholesterol levels were only associated with BMD at the total lumbar. Furthermore, total cholesterol was also negatively associated with osteocalcin, procollagen type I N-terminal propeptide, and β-crosslaps; high-density lipoprotein-cholesterol was only related to osteocalcin and parathyroid hormone, while low-density lipoprotein-cholesterol was only related to β-crosslaps in women. Conclusion: Our study suggests a significantly negative correlation between serum cholesterol levels and BMD in both men and women with T2D. The associations between serum cholesterol levels and bone turnover markers were also observed in T2D patients.

Oxidized phospholipids are ligands for LRP6

Low-density lipoprotein receptor-related protein 6 (LRP6) is a co-receptor for Wnt signaling and can be recruited by multiple growth factors/hormones to their receptors facilitating intracellular signaling activation. The ligands that bind directly to LRP6 have not been identified. Here, we report that bioactive oxidized phospholipids (oxPLs) are native ligands of LRP6, but not the closely related LRP5. oxPLs are products of lipid oxidation involving in pathological conditions such as hyperlipidemia, atherosclerosis, and inflammation. We found that cell surface LRP6 in bone marrow mesenchymal stromal cells (MSCs) decreased rapidly in response to increased oxPLs in marrow microenvironment. LRP6 directly bound and mediated the uptake of oxPLs by MSCs. oxPL-LRP6 binding induced LRP6 endocytosis through a clathrin-mediated pathway, decreasing responses of MSCs to osteogenic factors and diminishing osteoblast differentiation ability. Thus, LRP6 functions as a receptor and molecular target of oxPLs for their adverse effect on MSCs, revealing a potential mechanism underlying atherosclerosis-associated bone loss.

Soy protein improves tibial whole-bone and tissue-level biomechanical properties in ovariectomized and ovary-intact, low-fit female rats

BACKGROUND

Osteoporosis and related fractures, decreased physical activity, and metabolic dysfunction are serious health concerns for postmenopausal women. Soy protein might counter the negative effects of menopause on bone and metabolic health due to the additive or synergistic effects of its bioactive components.

OBJECTIVE

To evaluate the effects of ovariectomy (OVX) and a soy-protein diet (SOY) on bone outcomes in female, low-capacity running (LCR) rats selectively bred for low aerobic fitness as a model of menopause.

METHODS

At 27 weeks of age, LCR rats (N = 40) underwent OVX or sham (SHAM) surgery and were randomized to one of two isocaloric and isonitrogenous plant-protein-based dietary treatments: 1) soy-protein (SOY; soybean meal); or, 2) control (CON, corn-gluten meal), resulting in four treatment groups. During the 30-week dietary intervention, animals were provided ad libitum access to food and water; body weight and food intake were measured weekly. At completion of the 30-week intervention, body composition was measured using EchoMRI; animals were fasted overnight, euthanized, and blood and hindlimbs collected. Plasma markers of bone formation (osteocalcin, OC; N-terminal propeptide of type I procollagen, P1NP) and resorption (tartrate-resistant acid phosphatase, TRAP5b; C-terminal telopeptide of type I collagen, CTx) were measured using ELISA. Tibial trabecular microarchitecture and cortical geometry were evaluated using μCT; and torsional loading to failure was used to assess cortical biomechanical properties. Advanced glycation end-product (AGE) content of the femur was measured using a fluorimetric assay, and was expressed relative to collagen content measured by a colorimetric OH-proline assay. Two-factor ANOVA or ANOVCA was used to test for significant main and interactive effects of ovarian status (OV STAT: OVX vs. SHAM) and DIET (SOY vs. CON); final body weight was included as a covariate for body-weight-dependent cortical geometry and biomechanical properties.

RESULTS

OVX had significantly greater CTx than SHAM; SOY did not affect bone turnover markers. OVX adversely affected trabecular microarchitecture as evidenced by reduced BV/TV, trabecular thickness (Tb.Th), trabecular number (Tb.N), and connectivity density (Conn.D), and by increased trabecular separation (Tb.Sp) and structural model index (SMI). SOY increased BV/TV only in ovary-intact animals. There was no effect of OVX or SOY on tibial cortical geometry. In SHAM and OVX rats, SOY significantly improved whole-bone strength and stiffness; SOY also increased tissue-level stiffness and tended to increase tissue-level strength (p = 0.067). There was no effect of OVX or SOY on AGE content.

CONCLUSION

Soy protein improved cortical bone biomechanical properties in female low-fit rats, regardless of ovarian hormone status.

Study of microRNAs targeted Dvl2 on the osteoblasts differentiation of rat BMSCs in hyperlipidemia environment

Dishevelled 2 (Dvl-2), a key mediator of the wnt/β-catenin signaling pathway, plays critical roles in osteoblasts differentiation in hyperlipidemia environment. In our previous study, we observed a strong correlation between increased dvl2 expression and decreased new bone formation around implants in a rat hyperlipidemia implant surgery model. However, transcriptional regulation of Dvl2 by microRNAs in this process remains unknown. In the current study, we searched in online database and identified four significantly up-regulated miRNAs, miR-21-5p, miR-29c-3p, miR-138-5p, and miR-351-5p that could potentially regulate Dvl2. Using Western blot and dual-luciferase assays, we confirmed that miR29c-3p suppresses Dvl2 expression by binding to its 3'-UTR. Our results suggest a novel transcriptional regulation mechanism of Dvl2 by miR-29c-3p in osteoblasts differentiation of BMSCs.

Comparative impact of systemic delivery of atorvastatin, simvastatin, and lovastatin on bone mineral density of the ovariectomized rats

PURPOSE

In addition to lipid-lowering properties, statins have been suggested to affect bone turnover by increasing the osteoblastic bone formation and blocking the osteoclastogenesis. However, there are many controversial reports regarding the beneficial effect of statins on osteoporosis. In this study, we investigated the therapeutic effects of the most important lipophilic statins administered orally for 60 days to the ovariectomized (OVX) female Sprague-Dawley rats and compared the effects on different harvested trabecular and compact bones.

METHODS

Thirty female rats were divided into five equal groups including the normal rats, untreated OVX rats (negative control), and the OVX rats treated with atorvastatin (20 mg/kg/day), simvastatin (25 mg/kg/day), and lovastatin (20 mg/kg/day). The osteoporotic animals were treated daily for 60 days and euthanized at the end of experiments. The effectiveness of these treatments was evaluated by biomechanical testing, histopathologic, histomorphometric, micro-CT scan, real-time PCR, and serum biochemical analysis. Moreover, the hepatotoxicity and rhabdomyolysis related with these treatments were assessed by biochemistry analysis and histopathological evaluation.

RESULTS

The results and statistical analysis showed that systemic delivery of simvastatin and lovastatin significantly increased serum calcium level, expression of osteogenic genes, bone mineral density (BMD), and biomechanical properties in comparison to the untreated OVX rats, especially in trabecular bones (P < 0.05). The results of different analysis also indicated that there was no statistical difference between the atorvastatin-treated animals and the negative control. Among all treatments, only atorvastatin showed an evident hepatotoxicity and myopathy.

CONCLUSIONS

It was concluded that the lovastatin and simvastatin efficiently ameliorated the OVX-induced osteoporosis. Moreover, the simvastatin-treated animals showed more resemblance to the normal group in terms of BMD, expression of osteogenic genes, serum biochemical parameters, histomorphometric findings, and biomechanical performance with no significant side-effects.

Association between Serum Cholesterol Level and Osteoporotic Fractures

OBJECTIVE

Previous epidemiological studies have found an association between serum cholesterol level and bone mineral density. However, epidemiological studies evaluating the association between serum cholesterol level and the incidence of osteoporotic fracture are scant. Therefore, the objective of this study was to investigate whether serum cholesterol levels in Chinese participants aged 55 years or older was associated with an increased risk of osteoporotic fracture.

MATERIALS AND METHODS

We performed a cross-sectional study, including 1,791 participants (62.1% postmenopausal women and 213 fractures). Standardized self-administered questionnaires, physical examination, laboratory tests, and dual-energy X-ray absorptiometry examination were performed. Multivariate-adjusted logistic regression models were used to evaluate associations between serum cholesterol [total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL-C), and low-density lipoprotein (LDL-C)] levels and the osteoporotic fracture risk.

RESULTS

After adjusting for potential confounding factors, there were no associations between per SD increase in TC and LDL level and an increased risk of osteoporotic fracture in total participants, and in men and women as individual groups. There was a significant association between per SD increase in HDL-C level and an increased risk of osteoporotic fracture in total participants [odds ratios (OR) 1.20, 95% confidence interval (CI) 1.03, 1.40, P = 0.023] and in women (OR 1.37, 95% CI 1.12, 1.68, P = 0.003), whereas no association was observed in men (OR 1.01, 95% CI 0.73, 1.40, P = 0.951). Additionally, we found a significant association between per SD increase in TG level and an increased risk of osteoporotic fracture in total participants (OR 1.20, 95% CI 1.04, 1.38, P = 0.015). In women, a nonlinear relationship was observed between per SD increase in TG level and an increased risk of osteoporotic fracture. The risk of osteoporotic fracture in women increased with TG level >1.64 mmol/L (OR 1.93, 95% CI 1.24, 3.00, P = 0.004).

CONCLUSION

Among Chinese older adults, serum HDL-C level is significantly associated with a risk of osteoporotic fractures in women, and serum TG level is significantly associated with a risk of osteoporotic fractures in total participants and in women with TG >1.64 mmol/L.

Low-density lipoprotein receptor deficiency impaired mice osteoblastogenesis in vitro

Postmenopausal osteoporosis affected most elderly women with co-existence of lipid and bone metabolism disorders. However, the cellular and molecular mechanisms underlying the parallel progression and cross-talk of these systems remained unclear. In the present study, low-density lipoprotein receptor knockout (LDLR^-/-) mice were chosen to elucidate the effect of LDLR in regulating the differentiation of osteoblasts, which were responsible for bone formation and modulation of osteoclastogenesis. Primary osteoblasts were isolated from the calvarium of newborn LDLR^-/- or wild-type mice followed by osteoblastic differentiation culture in vitro. Alkaline phosphatase activity was significantly decreased in LDLR^-/- osteoblasts compared to wild-type controls, combined with calcium deposit formation delay, implying impaired osteoblastogenesis in vitro. Consistent with these findings, the expression of runt-related transcription factor 2 (Runx2) was decreased 3 days after differentiation in LDLR^-/- osteoblasts compared to wild-type controls. Moreover, the expression of Osterix was decreased 7 days after differentiation in LDLR^-/- osteoblasts compared to wild-type controls, later than Runx2.However, the osteoclastogenesis modulation role of osteoblasts was unaffected by the LDLR deficiency, evidenced by the same level of osteoprotegerin (OPG)/receptor activator of nuclear factor-κ B ligand (RANKL) axis between LDLR^-/- and wild-type control osteoblasts. Our results provide a novel insight into the role of LDLR during osteoblastic differentiation and improve understanding of cross-talk between bone and lipid metabolisms.

27-Hydroxycholesterol, an endogenous selective estrogen receptor modulator

Estrogen receptors (ERs) mediate the actions of the steroidal estrogens, and are important for the regulation of several physiological and pathophysiological processes, including reproduction, bone physiology, cardiovascular physiology and breast cancer. The unique pharmacology of the ERs allows for certain ligands, such as tamoxifen, to elicit tissue- and context-specific responses, ligands now referred to as selective estrogen receptor modulators (SERMs). Recently, the cholesterol metabolite 27-hydroxychoelsterol (27HC) has been defined as an endogenous SERM, with activities in atherosclerosis, osteoporosis, breast and prostate cancers, and neural degenerative diseases. Since 27HC concentrations closely mirror those of cholesterol, it is possible that 27HC mediates many of the biological effects of cholesterol. This paper provides an overview of ER pharmacology and summarizes the work to date implicating 27HC in various diseases. Wherever possible, we highlight clinical data in support of a role for 27HC in the diseases discussed.

Reduced femoral bone mass in both diet-induced and genetic hyperlipidemia mice

Growing evidence argues for a relationship between lipid and bone metabolisms with inconsistent conclusions. Sphingosine-1-phosphate (S1P) has been recognized as a suitable candidate for possible link between lipid metabolism and bone metabolism. This study was designed to investigate the effects of hyperlipidemia on bone metabolism using diet-induced and genetic-induced hyperlipidemia animal models and to explore whether S1P is involved. Wild-type mice and low-density lipoprotein receptor gene deficient (LDLR^-/-) mice at age of 8weeks were placed on either control diet or high-fat diet (HFD) for 12weeks. Bone structural parameters were determined using microCT. Cross-linked type I collagen (CTx) and S1P levels in plasma were measured by ELISA methods. Bone marrow cells from wild type and LDLR^-/- mice were induced to differentiate into osteoblasts, osteoclasts and adipocytes respectively. Gene expressions in distal femur metaphyses and cultured cells were studied by qRT-PCR. Moderate hypercholesterolemia was found in HFD-feeding mice; severe hypercholesterolemia and moderate hypertriglyceridemia were present in LDLR^-/- mice. Femoral trabecular bone mass was reduced in both diet-induced and genetic hyperlipidemia mice. Mice feeding on HFD showed higher CTx levels, and mice with hyperlipidemia had elevated S1P levels. Correlation analysis found a positive correlation between CTx and S1P levels. Lower Runx2 expression and higher TRAP expression were found in both diet-induced and genetic hyperlipidemia mice, indicating decreased osteoblastic functions and increased osteoclastic functions in these mice. Bone marrow cells from LDLR^-/- mice also showed increased adipogenesis and inhibited osteogenesis accompanied by enhanced PPARγ expression. In conclusion, our study found decreased bone mass in both diet-induced and genetic hyperlipidemia mice.

Hyperlipidemia induced by high-fat diet enhances dentin formation and delays dentin mineralization in mouse incisor

Dyslipidemia has become a serious health problem in children and adolescents worldwide for its high prevalence. Since hard tissues of permanent teeth form mainly during this period and lipids are actively involved in tooth development, the effects of hyperlipidemia on dental tissue formation and mineralization need to be illustrated. In this study, hyperlipidemia model was established in mice fed with high-fat diet (HFD). Micro-CT and histomorphological analyses were performed on the mandibular bones to assess the morphological changes of the mandibular incisor and first molar. After 4 weeks of HFD feeding, mice had significantly elevated serum lipid levels compared with mice fed with control diet. After 8 weeks, the mandibular incisor presented significantly increased dentin thickness and decreased diameter of pulp cavity in HFD-fed mice compared with control diet-fed mice, while its gross morphology and enamel thickness were not altered. In the mandibular first molar, dentin thickness of root did not show difference between the two groups. Histological section showed that mandibular incisor of HFD-fed mice manifested a wider predentin region and a lower mineral apposition rate compared with that of the control mice. In conclusion, hyperlipidemia induced by HFD feeding enhances dentin formation and delays dentin mineralization in the developing mouse incisor.

Apolipoprotein A-1 regulates osteoblast and lipoblast precursor cells in mice

Imbalances in lipid metabolism affect bone homeostasis, altering bone mass and quality. A link between bone mass and high-density lipoprotein (HDL) has been proposed. Indeed, it has been recently shown that absence of the HDL receptor scavenger receptor class B type I (SR-B1) causes dense bone mediated by increased adrenocorticotropic hormone (ACTH). In the present study we aimed at further expanding the current knowledge as regards the fascinating bone-HDL connection studying bone turnover in apoA-1-deficient mice. Interestingly, we found that bone mass was greatly reduced in the apoA-1-deficient mice compared with their wild-type counterparts. More specifically, static and dynamic histomorphometry showed that the reduced bone mass in apoA-1(-/-) mice reflect decreased bone formation. Biochemical composition and biomechanical properties of ApoA-1(-/-) femora were significantly impaired. Mesenchymal stem cell (MSC) differentiation from the apoA-1(-/-) mice showed reduced osteoblasts, and increased adipocytes, relative to wild type, in identical differentiation conditions. This suggests a shift in MSC subtypes toward adipocyte precursors, a result that is in line with our finding of increased bone marrow adiposity in apoA-1(-/-) mouse femora. Notably, osteoclast differentiation in vitro and osteoclast surface in vivo were unaffected in the knock-out mice. In whole bone marrow, PPARγ was greatly increased, consistent with increased adipocytes and committed precursors. Further, in the apoA-1(-/-) mice marrow, CXCL12 and ANXA2 levels were significantly decreased, whereas CXCR4 were increased, consistent with reduced signaling in a pathway that supports MSC homing and osteoblast generation. In keeping, in the apoA-1(-/-) animals the osteoblast-related factors Runx2, osterix, and Col1a1 were also decreased. The apoA-1(-/-) phenotype also included augmented CEPBa levels, suggesting complex changes in growth and differentiation that deserve further investigation. We conclude that the apoA-1 deficiency generates changes in the bone cell precursor population that increase adipoblast, and decrease osteoblast production resulting in reduced bone mass and impaired bone quality in mice.

Bone mineral density and intervertebral disc height in type 2 diabetes

BACKGROUND

Studies of the effect of type 2 diabetes (T2D) on bone mineral density (BMD have produced conflicting results, possibly due to failure to adjust for potential confounding factors. Nonetheless, T2D has consistently been associated with increased fracture risk, suggesting that other factors might play a role.

OBJECTIVE

This study assesses the relationship between T2D and BMD at the femoral neck and spine in diabetic and non-diabetic subjects, after adjusting for multiple covariates which may affect BMD. Intervertebral disc height was also investigated in view of its possible relation to fracture risk.

METHODS

A cross-sectional study of 100 patients with T2DM of at least 5 years duration and 86 non-diabetic subjects was carried out.

RESULTS

There were no significant differences in T scores in either the spine or femoral neck after adjustment for potential confounding variables between T2D subjects and controls. Diabetic patients had a statistically lower intervertebral disc height between the 2nd and 3rd lumbar vertebrae (D3) after adjustment for potential confounders (p=0.004). Urinary albumin:creatinine ratio, total cholesterol, LDL-cholesterol and cigarette smoking were independently associated with lower height of D3 in diabetic subjects.

CONCLUSIONS

There is no significant independent association between T2D and BMD. However we found a novel association of significantly lower disc height in patients with T2D. This may contribute to the increased vertebral fracture risk in subjects with T2D. Further studies are needed to investigate the relationship of disc height, T2D and fracture risk.

Advances in high-density lipoprotein physiology: surprises, overturns, and promises

Emerging evidence strongly supports that changes in the HDL metabolic pathway, which result in changes in HDL proteome and function, appear to have a causative impact on a number of metabolic disorders. Here, we provide a critical review of the most recent and novel findings correlating HDL properties and functionality with various pathophysiological processes and disease states, such as obesity, type 2 diabetes mellitus, nonalcoholic fatty liver disease, inflammation and sepsis, bone and obstructive pulmonary diseases, and brain disorders.

Prevalence and possible risk factors of low bone mineral density in untreated female patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by chronic inflammation. Different studies have shown decreased bone mineral density (BMD) in patients with SLE. The objective of this study was to investigate the prevalence and possible risk factors of low BMD in untreated female patients with SLE in Chinese population. A total of 119 untreated female patients with SLE were included. BMD was measured at lumbar spine and at total hip by dual-energy X-ray absorptiometry. The associations between decreased BMD and demographic variables, clinical variables, and bone metabolism variables were analyzed. These SLE patients had the following characteristics: mean age was 32.6 ± 11.9 years, mean disease duration was 22.1 ± 34.5 months, and mean SLEDAI was 11.4 ± 5.4. Osteopenia was present in 31.1% of the patients and osteoporosis in 8.5%. A significant negative association between low density lipoprotein cholesterol (LDL-c) and BMD at the lumbar spine (correlation coefficient = −0.242; P = 0.023) and total hip (correlation coefficient = −0.259; P = 0.019) was shown. These results seem to indicate that increased LDL-c may be an important risk factor for low BMD at lumbar spine and total hip in untreated female SLE patients.