Role of APOE Gene in Bone Mineral Density and Incidence of Bone Fractures in Brazilian Postmenopausal Women

Network Analysis of Brain and Bone Tissue Transcripts Reveals Shared Molecular Mechanisms Underlying Alzheimer's Disease and Related Dementias and Osteoporosis

BACKGROUND

Alzheimer's disease and related dementias (ADRD) and osteoporosis (OP) are 2 prevalent diseases of aging with demonstrated epidemiological association, but the underlying molecular mechanisms contributing to this association are unknown.

METHODS

We used network analysis of bone and brain transcriptomes to discover common molecular mechanisms underlying these 2 diseases. Our study included RNA-sequencing data from the dorsolateral prefrontal cortex tissue of autopsied brains in 629 participants from ROSMAP (Religious Orders Study and the Rush Memory and Aging Project), with a subgroup of 298 meeting criteria for inclusion in 5 ADRD categories, and RNA array data from transiliac bone biopsies in 84 participants from the Oslo study of postmenopausal women. After developing each network within each tissue, we analyzed associations between modules (groups of coexpressed genes) with multiple bone and neurological traits, examined overlap in modules between networks, and performed pathway enrichment analysis to discover conserved mechanisms.

RESULTS

We discovered 3 modules in ROSMAP that showed significant associations with ADRD and bone-related traits and 4 modules in Oslo that showed significant associations with multiple bone outcomes. We found significant module overlap between the 2 networks in modules linked to signaling, tissue homeostasis, and development, and Wingless-related integration site (Wnt) signaling was found to be highly enriched in OP and ADRD modules of interest.

CONCLUSIONS

These results provide translational opportunities in the development of treatments and biomarkers for ADRD and OP.

Causal relationships of familial hypercholesterolemia with the risk of multiple vitamin deficiencies: a Mendelian randomization study

Background

The causal relationship between familial hypercholesterolemia (FH) and various vitamin deficiencies has not yet been elucidated. Therefore, this study investigated the cause-and-effect relationship between FH and the risk of multiple vitamin deficiencies in humans.

Methods

Mendelian randomization (MR) analysis was performed by extracting six datasets for FH, FH with ischemic heart disease (IHD), and vitamin deficiency (vitamin A, thiamine, other B-group vitamins, and vitamin D) from the FinnGen study, covering a total of 329,115; 316,290; 354,932; 354,949; 355,411 and 355,238 individuals, respectively.

Results

FH was suggestively associated with higher odds of thiamine deficiency [inverse variance weighted odds ratio (ORIVW) 95% confidence interval (CI): 1.62 (1.03, 2.55), P = 0.036] and vitamin D deficiencies [ORIVW CI: 1.35 (1.04, 1.75), P = 0.024], low-density lipoprotein receptor (LDLR) rs112898275 variant, rs11591147 and rs499883 in proprotein convertase subtilisin/kexin 9 (PCSK9), rs9644862 in cyclin-dependent kinase inhibitor 2 B antisense RNA1 (CDKN2B-AS1), and rs142834163 in dedicator of cytokinesis 6 (DOCK6) and rs115478735 in ABO blood group (ABO) strongly influenced the risk of thiamine deficiency, while the rs7412 variant in apolipoprotein E (APOE) mostly influenced the risk of vitamin D deficiency. FH with IHD was suggestively associated with higher odds of vitamin D deficiency (ORIVW, weighted median [WM][95%CI]: 1.31 [1.05, 1.64]; 1.47 [1.10, 1.97]) (P = 0.018; 0.010) without any single significant SNPs observed.

Conclusion

FH was positively associated with increased risks of thiamine and vitamin D deficiencies, revealing a prospective and unfortunate complication of FH.

Crosstalk between bone and brain in Alzheimer's disease: Mechanisms, applications, and perspectives

Alzheimer's disease (AD) is a neurodegenerative disease that involves multiple systems in the body. Numerous recent studies have revealed bidirectional crosstalk between the brain and bone, but the interaction between bone and brain in AD remains unclear. In this review, we summarize human studies of the association between bone and brain and provide an overview of their interactions and the underlying mechanisms in AD. We review the effects of AD on bone from the aspects of AD pathogenic proteins, AD risk genes, neurohormones, neuropeptides, neurotransmitters, brain-derived extracellular vesicles (EVs), and the autonomic nervous system. Correspondingly, we elucidate the underlying mechanisms of the involvement of bone in the pathogenesis of AD, including bone-derived hormones, bone marrow-derived cells, bone-derived EVs, and inflammation. On the basis of the crosstalk between bone and the brain, we propose potential strategies for the management of AD with the hope of offering novel perspectives on its prevention and treatment. HIGHLIGHTS: The pathogenesis of AD, along with its consequent changes in the brain, may involve disturbing bone homeostasis. Degenerative bone disorders may influence the progression of AD through a series of pathophysiological mechanisms. Therefore, relevant bone intervention strategies may be beneficial for the comprehensive management of AD.

Changes in bone turnover markers 6-12 months after bariatric surgery

A rise in bone turnover markers (BTM) after bariatric surgery predicts poor bone health years later. This study explored factors associated with BTM and changes in BTM after bariatric surgery. Inclusion criteria were subjects 18 to 65 years of age with morbid obesity undergoing bariatric surgery. All data were measured before and 6 and 12 months after surgery. The study included 104 subjects: women/men: 83/21; mean age 43.1 (SD 8.4) years; BMI: 38.8 kg/m2 (SD 3.8). Surgery with Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) was performed in 84 (81%) and 20 (19%) subjects, respectively. From before to 6-12 months after surgery, procollagen type 1 N-terminal propeptid (P1NP) increased by 45.6 µg/L (95% CI 41.5-50.0, p < 0.001), and alkaline phosphatase (ALP) by 10 U/L (95% CI 7-14, p < 0.001). The increases were significantly larger after RYGB than after SG. The APOE- Ɛ3 allele was associated with low levels of BTM and high levels of leptin. There was an unfavourable increase in BTM after bariatric surgery. SG compared to RYGB and the presence of the APOE-Ɛ3 allele were associated with less unfavourable effects. The study emphasises the importance of optimal prophylactic interventions after bariatric surgery to prevent osteoporosis.

Degradation of Bone Quality in a Transgenic Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) patients present with symptoms such as impairment of insulin signaling, chronic inflammation, and oxidative stress. Furthermore, there are comorbidities associated with AD progression. For example, osteoporosis is common with AD wherein patients exhibit reduced mineralization and a risk for fragility fractures. However, there is a lack of understanding on the effects of AD on bone beyond loss of bone density. To this end, we investigated the effects of AD on bone quality using the 5XFAD transgenic mouse model in which 12-month-old 5XFAD mice showed accumulation of amyloid-beta (Aβ42) compared with wild-type (WT) littermates (n = 10/group; 50% female, 50% male). Here, we observed changes in cortical bone but not in cancellous bone quality. Both bone mass and bone quality, measured in femoral samples using imaging (micro-CT, confocal Raman spectroscopy, X-ray diffraction [XRD]), mechanical (fracture tests), and chemical analyses (biochemical assays), were altered in the 5XFAD mice compared with WT. Micro-CT results showed 5XFAD mice had lower volumetric bone mineral density (BMD) and increased endocortical bone loss. XRD results showed decreased mineralization with smaller mineral crystals. Bone matrix compositional properties, from Raman, showed decreased crystallinity along with higher accumulation of glycoxidation products and glycation products, measured biochemically. 5XFAD mice also demonstrated loss of initiation and maximum toughness. We observed that carboxymethyl-lysine (CML) and mineralization correlated with initiation toughness, whereas crystal size and pentosidine (PEN) correlated with maximum toughness, suggesting bone matrix changes predominated by advanced glycation end products (AGEs) and altered/poor mineral quality explained loss of fracture toughness. Our findings highlight two pathways to skeletal fragility in AD through alteration of bone quality: (i) accumulation of AGEs; and (ii) loss of crystallinity, decreased crystal size, and loss of mineralization. We observed that the accumulation of amyloidosis in brain correlated with an increase in several AGEs, consistent with a mechanistic link between elevated Aβ42 levels in the brain and AGE accumulation in bone. © 2022 American Society for Bone and Mineral Research (ASBMR).

Osteoporosis and cognitive impairment interwoven warning signs: community-based study on older adults-Bushehr Elderly Health (BEH) Program

Cognitive impairment and osteoporosis are frequently seen to coincide in clinical practice. Osteoporosis was higher in elderly populations with cognitive impairment, especially in postmenopausal women. Thus, prophylaxis for osteoporosis, falls, and fractures should be considered as part of the treatment of patients with cognitive impairment.

INTRODUCTION

Cognitive impairment and osteoporosis are two important health concerns among older adults that their possible relationship, concurrent occurrence, and linking mechanism have recently been highlighted. The purpose of this study was to assess the sex-independent association of these two conditions.

MATERIALS AND METHODS

From among 2331 individuals aged ≥ 60 years selected in Bushehr Elderly Health (BEH) Program, Iran; data of 1508 participants were analyzed. Cognitive status was assessed using Category Fluency Test and Mini-cog assessment instrument. Association between osteopenia-osteoporosis and cognitive impairment were assessed using uni- and multivariable logistic regression models.

RESULTS

Osteoporosis was diagnosed in 598 (39.6%) of the participants (58.3% female and 21.9% male, P < 0.001). From among them, 677 (44.9%) had evidence of cognitive impairment (64.5% female and 31.0% male, P < 0.001). Multivariate logistic regressions showed spinal and total hip osteoporosis was associated with 1.83 (CI 95% 1.13-2.96) and 2.24-fold (CI 95% 1.28-3.89) increase in the risk of cognitive impairment among female subjects, respectively. Ordinal logistic regression, on the other hand, revealed cognitive impairment to be associated with 1.42-fold (CI 95% 1.04-1.92) increase in the risk of spinal osteopenia-osteoporosis, 1.5-fold increase in total hip osteoporosis (CI 95% 1.09-2.05), and 1.48-fold increase in general osteoporosis (CI 95% 1.06-2.0).

CONCLUSION

Different degrees of bone loss and cognitive impairment may be a risk factor for each other among women but not in men. It is suggested that the screening, adopting preventive measures for the other condition and regular follow-ups, if needed, could be of utmost importance.

Artificial intelligence, osteoporosis and fragility fractures

PURPOSE OF REVIEW

Artificial intelligence tools have found new applications in medical diagnosis. These tools have the potential to capture underlying trends and patterns, otherwise impossible with previous modeling capabilities. Machine learning and deep learning models have found a role in osteoporosis, both to model the risk of fragility fracture, and to help with the identification and segmentation of images.

RECENT FINDINGS

Here we survey the latest research in the artificial intelligence application to the prediction of osteoporosis that has been published between January 2017 and March 2019. Around half of the articles that are covered here predict (by classification or regression) an indicator of osteoporosis, such as bone mass or fragility fractures; the other half of studies use tools for automatic segmentation of the images of patients with or at risk of osteoporosis. The data for these studies include diverse signal sources: acoustics, MRI, CT, and of course, X-rays.

SUMMARY

New methods for automatic image segmentation, and prediction of fracture risk show promising clinical value. Though these recent developments have had a successful initial application to osteoporosis research, their development is still under improvement, such as accounting for positive/negative class bias. We urge care when reporting accuracy metrics, and when comparing such metrics between different studies.

Chronic Oral Administration of Tenebrio molitor Extract Exhibits Inhibitory Effect on Glucocorticoid Receptor Overexpression in the Hippocampus of Ovariectomy-Induced Estrogen Deficient Mice

It has been reported that estrogen deficiency in female disrupts systemic endocrinologic regulatory mechanisms, finally leading to osteoporotic condition. Estrogen deficiency also down-regulates brain functions due to its deficits of its original roles in a number of neurological events. Therefore, it is necessary to find alternative materials that can prevent osteoporotic condition and maintain normal brain functions to correct such hormone deficiency. In the present study, we found that novel compounds originated from larvae of Tenebrio molitor (TM) possessed anti-osteoporotic effect. They could also prevent abnormal progressive brain function by deaccelerating enhanced HPA-axis negative feedback while maintaining neurogenesis in hippocampus. We daily administered TM to ovariectomized (OVX) ddY mice for 4 weeks and then performed histological and hormonal evaluations for its anti-osteoporotic effects. In addition, we investigated glucocorticoid receptor (GR) expression and neuroblast expression (DCX) in the hippocampal dentate gyrus morphologically by immunohistochemistry analysis. According to our results, TM has anti-osteoporotic effects. It also tends to bring interfered brain environment back to normal condition. These results suggest that TM might have anti-osteoporosis effect and enhancing effects on enrichment of environment in brain by being antidestroyed hormonal deficiency simultaneously. This is the first study to report that TM can be used as source of bioactive substance to prevent decreased neurogenesis and impaired HPA axis driven by high GR expression in the hippocampus in hormonal deficient female animals. PRACTICAL APPLICATION: Anti-osteoporosis effect and stress resistance due to improved brain function caused by the ingestion of Tenebrio molitor extract were observed in postmenopausal women. T. molitor is available as a nutritional supplement for bone and brain health, which menopausal women need most.

Reduced CpG island methylation of the TBC1D8 gene may predict risk for osteoporosis in Chinese postmenopausal women

Objective: In this study, we collected samples from postmenopausal women aged >60 y and evaluated bone mineral density (BMD) in addition to other biochemical variables to evaluate risk factors for osteoporosis. Furthermore, we investigated whether an association exists between the CpG island methylation levels in the promoter region of the TBC1D8 gene and osteoporosis incidence. Our goal was to identify contributing factors to the pathogenesis of osteoporosis and provide a theoretical basis for osteoporosis testing and therapy.

Materials and Methods: We used questionnaires to collect data from Chinese Han women in their communities. The following parameters were measured: uric acid, high density lipoprotein, low density lipoprotein, fasting blood glucose, serum creatinine, serum calcium, serum phosphorus, alkaline phosphatase, P1NP, β-CTX, PTH, 25(OH)D and bone mineral density from lumbar spine 1 to 4, femoral neck, and total hip. DNA was also extracted to assess the methylation level of the TBC1D8 gene.

Conclusions: Our findings suggest that a lower body mass index (BMI) infrequent exercise and certain sleep durations may be associated with osteoporosis. In addition, higher serum creatinine, β-CTX and PTH and lower 25(OH)D levels may be associated with osteoporosis. In Chinese Han postmenopausal women, decreased methylation of the TBCF1D8 gene promoter CpG islands is associated with osteoporosis. Finally, we also observed that TBC1D8 is negatively correlated with high density lipoprotein in postmenopausal women with osteoporosis.