Causal relationship between the AHSG gene and BMD through fetuin-A and BMI: multiple mediation analysis

Simple prediction model for vitamin D deficiency in women with osteoporosis or risk factors for osteoporosis in Thailand

Introduction

In Thailand, the assessment of vitamin D status by measuring 25-hydroxyvitamin D[25(OH)D] levels in individuals at risk for osteoporosis is constrained by limited facilities and high costs. This study aimed to create a clinical model for predicting vitamin D deficiency in women with osteoporosis or risk factors for osteoporosis.

Materials and Methods

This was a cross-sectional study of 490 women. All participants had 25(OH)D levels measured. A questionnaire was used to assess factors related to vitamin D status. Vitamin D deficiency was defined as 25(OH)D levels < 30 ng/mL. Logistic regression analyses were conducted to investigate predictors of vitamin D deficiency. In the model, odds ratios (ORs) were converted into simple scores. The optimal cutoff for women at a high risk of vitamin D deficiency was established. Internal validation was assessed using a Bootstrap.

Results

Sixty percent had vitamin D deficiency. The final model for predicting vitamin D deficiency consisted of a body mass index ≥ 25 kg/m2 (OR:1.15), lack of exercise (OR:1.59), exercise 1-2 times/week (OR:1.40), sunlight exposure < 15 min/day (OR:1.70), no vitamin D supplementation (OR:8.76), and vitamin D supplementation of 1-20,000 IU/week (OR:2.31). The area under the curve was 0.747. At a cutoff of 6.6 in total risk score (range 4-13.6), the model predicted vitamin D deficiency with a sensitivity of 71.9 % and a specificity of 65.3 %. The internal validation by Bootstrap revealed a ROC of 0.737.

Conclusions

In women at risk of osteoporosis, a simple risk score can identify individuals with a high risk of vitamin D deficiency. These women could benefit from vitamin D supplementation without requiring 25(OH)D measurements.

Current issues in evaluation and management of osteoporosis in Thailand

Osteoporosis is a major public health issue in Thailand, which increased morbidity, mortality, and health-care utilization. The objective of this review is to provide current perspectives on epidemiology, evaluation and management of osteoporosis in Thailand. According to epidemiologic data, the prevalence of osteoporosis and the incidence of hip fracture were comparable to the rest of the world. However, among Thai postmenopausal women, the prevalence of asymptomatic vertebral fracture was disproportionately high. In addition to established risk factors, conditions that may affect the risk of osteoporosis in the Thai population include certain genetic variants, thalassemia, vitamin D deficiency, and low dietary calcium intake, which requires further investigations to draw conclusions. In 2021, the Thai Osteoporosis Foundation released a new Clinical Practice Guideline that provides up-to-date evidence-based recommendations for evaluation and management of osteoporosis. Nonetheless, more research is required to provide local evidence in a variety of areas to guide management of osteoporosis in Thailand. These include epidemiology of distal radial fracture, the optimal intervention threshold of the Thai-specific Fracture Risk Assessment Tool model, screening for asymptomatic vertebral fracture, and the economic evaluation of osteoporosis management options, including fracture liaison service.

The roles of hepatokine and osteokine in liver-bone crosstalk: Advance in basic and clinical aspects

Both the liver and bone are important secretory organs in the endocrine system. By secreting organ factors (hepatokines), the liver regulates the activity of other organs. Similarly, bone-derived factors, osteokines, are created during bone metabolism and act in an endocrine manner. Generally, the dysregulation of hepatokines is frequently accompanied by changes in bone mass, and osteokines can also disrupt liver metabolism. The crosstalk between the liver and bone, particularly the function and mechanism of hepatokines and osteokines, has increasingly gained notoriety as a topic of interest in recent years. Here, based on preclinical and clinical evidence, we summarize the potential roles of hepatokines and osteokines in liver-bone interaction, discuss the current shortcomings and contradictions, and make recommendations for future research.

A Comparison of Bone Mineral Density and Its Predictors in HIV-Infected and HIV-Uninfected Older Men

OBJECTIVE

Bone health in older individuals with HIV infection has not been well studied. This study aimed to compare bone mineral density (BMD), trabecular bone score (TBS), and bone markers between HIV-infected men and age- and body mass index (BMI)-matched HIV-uninfected men aged ≥60 years. We investigated the associations of risk factors related to fracture with BMD, TBS, and bone markers in HIV-infected men.

METHODS

This cross-sectional study included 45 HIV-infected men receiving antiretroviral therapy and 42 HIV-uninfected men. Medical history, BMD and TBS measurements, and laboratory tests related to bone health were assessed in all the participants. HIV-related factors known to be associated with bone loss were assessed in the HIV-infected men.

RESULTS

The mean BMD, TBS, and osteopenia or osteoporosis prevalence were similar among the cases and controls. The HIV-infected men had significantly higher mean N-terminal propeptide of type 1 procollagen and C-terminal cross-linking telopeptide of type I collagen levels. Stepwise multiple linear regression analysis demonstrated that low BMI (lumbar spine, P = .015; femoral neck, P = .018; and total hip, P = .005), high C-terminal cross-linking telopeptide of type I collagen concentration (total hip, P = .042; and TBS, P = .010), and low vitamin D supplementation (TBS, P = .035) were independently associated with low BMD and TBS.

CONCLUSION

In older HIV-infected men with a low fracture risk, the mean BMD and TBS were similar to those of the age- and BMI-matched controls. The mean bone marker levels were higher in the HIV group. Traditional risk factors for fracture, including low BMI, high C-terminal cross-linking telopeptide of type I collagen level, and low vitamin D supplementation, were significant predictors of low BMD and TBS.

Vitamin D and Calcium Supplement Attenuate Bone Loss among HIVInfected Patients Receiving Tenofovir Disoproxil Fumarate/Emtricitabine/ Efavirenz: An Open-Label, Randomized Controlled Trial

BACKGROUND

Antiretroviral therapy (ART), especially with tenofovir disoproxil fumarate (TDF), has been associated with accelerated bone turnover and leads to significant bone loss.

OBJECTIVE

We aimed to determine the effect of vitamin D2 and calcium on bone mineral density (BMD) in HIV-infected patients receiving TDF/emtricitabine (FTC)/efavirenz (EFV).

METHODS

A prospective, open-label, randomized controlled study was conducted. Eligible patients were ART naïve HIV individuals who initiated TDF/FTC/EFV. The study group received supplementation with vitamin D2 and calcium carbonate, whereas the control group was administered only ART. The primary outcome was the percentage change in total hip BMD at week 24 compared with baseline.

RESULTS

A total of 18 patients were randomized (9 in each group). The mean (standard deviation; SD) total hip BMD significantly decreased from baseline in both groups, from 0.96 (0.14) g/cm2 to 0.93 (0.13) g/cm2 in the study group (p = 0.006) and from 0.87 (0.11) g/cm2 to 0.84 (0.11) g/cm2 in the control group (p = 0.004). The mean (SD) lumbar spine BMD significantly decreased from baseline in both groups, from 1.00 (0.13) g/cm2 to 0.97 (0.13) g/cm2 (p = 0.004) in the study group and from 0.90 (0.09) g/cm3 to 0.86 (0.08) g/cm2 in the control group (p = 0.006). At week 24, the mean (SD) lumbar spine BMD was significantly greater in the study group than in the control group (p = 0.042). However, there were no significant differences in the percentage change of total hip, lumbar spine, and femoral neck BMD between both groups. No adverse events were reported. In conclusion, as early as 24 weeks after TDF initiation, a significant decline in BMD was detected.

CONCLUSION

Vitamin D2 and calcium supplements should be considered for HIV-infected patients receiving TDF/FTC/EFV in a resource-limited setting where there are limited ART options (Clinicaltrials. gov NCT0287643).

The differences in the relationship between obstructive sleep apnea severity and trabecular bone score in men and women with type 2 diabetes

Aims

Type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA) may adversely affect bone. Gender is a well-established factor influencing bone health. We investigated the impact of OSA on bone mineral density (BMD) and trabecular bone score (TBS) in T2DM.

Methods

Eighty-one T2DM patients [33 men and 48 women] participated. OSA was diagnosed using an overnight monitor, with its severity assessed by an apnea hypopnia index (pAHI). The measurements of hypoxia, including the percentage of total sleep time in which oxygen saturation remains below 90% (pT90), the oxygen desaturation index (pODI) and minimum O₂ (min O₂), were reported. Lumbar spine (L1-4) and femoral neck (FN) BMD were measured using dual-energy X-ray absorptiometry (DXA). TBS was computed from DXA images.

Results

Sixty-five patients (80.2%) had OSA. pAHI, pT90, pODI and min O₂ were not correlated to L1-4 BMD, FN BMD or TBS in all participants by multiple regression analyses adjusting for age, gender and BMI. However, an interaction between gender and pAHI, and gender and pODI were significantly associated with TBS (b = 0.003, p = 0.034 and b = 0.004, p = 0.046, respectively). We therefore reassessed an association between pAHI or pODI and TBS separately between men and women. After adjusting for age and BMI, more severe OSA (higher pAHI) and higher pODI significantly associated with lower TBS (b = -0.002, p = 0.034 and b = -0.003, p = 0.021, respectively) in men. On the other hand, higher pAHI non-significantly associated with better trabecular microarchitecture as indicated by higher TBS (b = 0.002, p = 0.059) in women. When considered only postmenopausal (n = 33), higher pAHI and higher pODI were significantly associated with higher TBS (b = 0.004, p = 0.003 and b = 0.004, p = 0.008, respectively).

Conclusions

In T2DM patients, there is a complex interrelationship among OSA severity, gender and TBS. More severe OSA predicted lower TBS in men, but predicted higher TBS in postmenopausal women.

A genetic stochastic process model for genome-wide joint analysis of biomarker dynamics and disease susceptibility with longitudinal data

Unraveling the underlying biological mechanisms or pathways behind the effects of genetic variations on complex diseases remains one of the major challenges in the post-GWAS (where GWAS is genome-wide association study) era. To further explore the relationship between genetic variations, biomarkers, and diseases for elucidating underlying pathological mechanism, a huge effort has been placed on examining pleiotropic and gene-environmental interaction effects. We propose a novel genetic stochastic process model (GSPM) that can be applied to GWAS and jointly investigate the genetic effects on longitudinally measured biomarkers and risks of diseases. This model is characterized by more profound biological interpretation and takes into account the dynamics of biomarkers during follow-up when investigating the hazards of a disease. We illustrate the rationale and evaluate the performance of the proposed model through two GWAS. One is to detect single nucleotide polymorphisms (SNPs) having interaction effects on type 2 diabetes (T2D) with body mass index (BMI) and the other is to detect SNPs affecting the optimal BMI level for protecting from T2D. We identified multiple SNPs that showed interaction effects with BMI on T2D, including a novel SNP rs11757677 in the CDKAL1 gene (P = 5.77 × 10-7 ). We also found a SNP rs1551133 located on 2q14.2 that reversed the effect of BMI on T2D (P = 6.70 × 10-7 ). In conclusion, the proposed GSPM provides a promising and useful tool in GWAS of longitudinal data for interrogating pleiotropic and interaction effects to gain more insights into the relationship between genes, quantitative biomarkers, and risks of complex diseases.

Age-Adjusted Dual X-ray Absorptiometry-Derived Trabecular Bone Score Curve for the Lumbar Spine in Thai Females and Males

Trabecular bone score (TBS), which has been shown to discriminate patients with fractures from healthy individuals, decreases with age. This study was conducted to derive an age-adjusted normative TBS curve for each gender aged 30-80 + years to serve as reference data for Thai males and females. A cross-sectional study was conducted among employees from the Electricity Generating Authority of Thailand cohorts, after excluding those with conditions potentially affecting bone metabolism and analysis. The values of TBS at L1-L4 vertebrae were analyzed using a commercial software. Age-adjusted TBS curves were constructed using segmental linear regression analysis for each gender. Additional analysis was also performed on TBS with age, body mass index, and body mineral density (BMD) at L1-L4 vertebrae as covariates. A database of 848 healthy subjects (341 females and 507 males) aged 30-80+ years was created. The BMDs of both male and female subjects in the youngest decade were not statistically different from previous reports (p = 0.31 and 0.22 for females and males, respectively). In this age group, the mean TBS was higher in females, albeit not statistically significant (p = 0.12). Between the ages of 30-80+ years, female and male TBS dropped by 19.8% (0.40% per year) and 10.1% (0.20% per year), respectively. The association with TBS was weak for body mass index and moderate for BMD (coefficients of about -0.01 and 0.4-0.5, respectively). The age-adjusted reference curves for healthy Thai females and males aged 30-80+ years have been established.

Allelic Imbalance of mRNA Associated with α2-HS Glycoprotein (Fetuin-A) Polymorphism

Alpha 2-HS glycoprotein (AHSG), also designated as fetuin-A, exhibits polymorphism in population genetics consisting of two major alleles of AHSG^∗1 and AHSG^∗2. The serum level in the AHSG^∗1 homozygote is significantly higher than that of the AHSG^∗2 homozygote. This study examined the molecular mechanism for the cis-regulatory expression. To quantitate allele-specific mRNA in intra-assays of the heterozygote, RT-PCR method employing primers that were incorporated to the two closely located SNPs was developed. The respective magnitudes of AHSG^∗1 to AHSG^∗2 in the liver tissues and hepatic culture cells of PLC/PRF/5 were determined quantitatively as 2.5-fold and 6.2-fold. The mRNA expressional difference of two major alleles was observed, which is consistent with that in the serum level. The culture cells carried heterozygous genotypes in rs4917 and rs4918, but homozygous one in rs2248690. It was unlikely that the imbalance was derived from the SNP located in the promotor site. Furthermore, to investigate the effect of mRNA degradation, RNA synthesis in the cell culture was inhibited potently by the addition of actinomycin-D. No marked change was apparent between the two alleles. The results indicated that the cis-regulatory expressional difference is expected to occur at the level of transcription or splicing of mRNA.

The role of fetuin-A in mineral trafficking and deposition

Calcium and phosphate are the principle ions involved in the deposition of mineral in the human body. Inhibitors of mineralisation are essential for the prevention of ectopic mineral precipitation and deposition. In the past decade, through in vitro, in vivo and clinical observation studies, we have come to appreciate the importance of fetuin-A (Fet-A), a circulating glycoprotein, in preventing ectopic calcium phosphate mineralisation. Moreover, the detection of Fet-A-containing mineral complex, termed calciprotein particles (CPPs), has provided new ways to assess an individual's calcific risk. The pathophysiological significance of CPPs in disease states is yet to be defined, but it provides an exciting avenue to further our understanding of the development of ectopic mineralisation.

Proteomic analysis of cerebrospinal fluid in canine cervical spondylomyelopathy

STUDY DESIGN

Prospective study.

OBJECTIVE

To identify proteins with differential expression in the cerebrospinal fluid (CSF) from 15 clinically normal (control) dogs and 15 dogs with cervical spondylomyelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Canine CSM is a spontaneous, chronic, compressive cervical myelopathy similar to human cervical spondylotic myelopathy. There is a limited knowledge of the molecular mechanisms underlying these conditions. Differentially expressed CSF proteins may contribute with novel information about the disease pathogenesis in both dogs and humans.

METHODS

Protein separation was performed with 2-dimensional electrophoresis. A Student t test was used to detect significant differences between groups (P < 0.05). Three comparisons were made: (1) control versus CSM-affected dogs, (2) control versus non-corticosteroid-treated CSM-affected dogs, and (3) non-corticosteroid-treated CSM-affected versus corticosteroid-treated CSM-affected dogs. Protein spots exhibiting at least a statistically significant 1.25-fold change between groups were selected for subsequent identification with capillary-liquid chromatography tandem mass spectrometry.

RESULTS

A total of 96 spots had a significant average change of at least 1.25-fold in 1 of the 3 comparisons. Compared with the CSF of control dogs, CSM-affected dogs demonstrated increased CSF expression of 8 proteins including vitamin D-binding protein, gelsolin, creatine kinase B-type, angiotensinogen, α-2-HS-glycoprotein, SPARC (secreted protein, acidic, rich in cysteine), calsyntenin-1, and complement C3, and decreased expression of pigment epithelium-derived factor, prostaglandin-H2 D-isomerase, apolipoprotein E, and clusterin. In the CSF of CSM-affected dogs, corticosteroid treatment increased the expression of haptoglobin, transthyretin isoform 2, cystatin C-like, apolipoprotein E, and clusterin, and decreased the expression of angiotensinogen, α-2-HS-glycoprotein, and gelsolin.

CONCLUSION

Many of the differentially expressed proteins are associated with damaged neural tissue, bone turnover, and/or compromised blood-spinal cord barrier. The knowledge of the protein changes that occur in CSM and upon corticosteroid treatment of CSM-affected patients will aid in further understanding the pathomechanisms underlying this disease.

LEVEL OF EVIDENCE

N/A.

Serum fetuin-A levels in subjects with and without choroid plexus calcification

Choroid plexus is an intraventricular plexus of tissue which is responsible for secretion of cerebrospinal fluid. Calcification of choroid plexus is found to be associated with age and gender. One of novel and popular glycoprotein that involves in inhibition of mineralization is human fetuin-A. In our study, we investigated plasma levels of fetuin-A in subjects with and without choroid plexus calcification. For this purpose, 41 subjects with choroid plexus calcification and 41 age and gender matched subjects with normal appearing choroid plexus were recruited. Calcified and normal choroid plexus tissue identified on computed tomography images. Overnight fasting venous blood samples were collected to measure serum fetuin-A levels using a human fetuin-A enzyme-linked immunosorbent assay kit. Statistically significant difference concerning the median concentration of fetuin-A was found between subjects with and without choroid plexus calcification (p: 0.040). Significance was also present between male subgroups (p: 0.017) and 18-27 years age subgroups (p: 0.025). Our results suggest that fetuin-A has an potent role in calcification process of choroid plexus.