Gut microbially produced tryptophan metabolite melatonin ameliorates osteoporosis via modulating SCFA and TMAO metabolism

Osteoporosis (OP) is a severe global health issue that has significant implications for productivity and human lifespan. Gut microbiota dysbiosis has been demonstrated to be closely associated with OP progression. Melatonin (MLT) is an important endogenous hormone that modulates bone metabolism, maintains bone homeostasis, and improves OP progression. Multiple studies indicated that MLT participates in the regulation of intestinal microbiota and gut barrier function. However, the promising effects of gut microbiota-derived MLT in OP remain unclear. Here, we found that OP resulted in intestinal tryptophan disorder and decreased the production of gut microbiota-derived MLT, while administration with MLT could mitigate OP-related clinical symptoms and reverse gut microbiota dysbiosis, including the diversity of intestinal microbiota, the relative abundance of many probiotics such as Allobaculum and Parasutterella, and metabolic function of intestinal flora such as amino acid metabolism, nucleotide metabolism, and energy metabolism. Notably, MLT significantly increased the production of short-chain fatty acids and decreased trimethylamine N-oxide-related metabolites. Importantly, MLT could modulate the dynamic balance of M1/M2 macrophages, reduce the serum levels of pro-inflammatory cytokines, and restore gut-barrier function. Taken together, our results highlighted the important roles of gut microbially derived MLT in OP progression via the "gut-bone" axis associated with SCFA metabolism, which may provide novel insight into the development of MLT as a promising drug for treating OP.

Bone Health Impairment in Patients with Hemoglobinopathies: From Biological Bases to New Possible Therapeutic Strategies

Hemoglobinopathies are monogenic disorders affecting hemoglobin synthesis. Thalassemia and sickle cell disease (SCD) are considered the two major hemoglobinopathies. Thalassemia is a genetic disorder and one of the major hemoglobinopathies determined by an impairment of globin chain production, which causes an alteration of erythropoiesis, an improvement in hemolysis, and an alteration of iron homoeostasis. In SCD, the mutations are on the β-globin chain of hemoglobin which results in a substitution of glutamic acid by valine with consequent formation of Hemoglobin S (HbS). Several factors are involved in bone metabolism alteration in patients with hemoglobinopathies, among them hormonal deficiency, bone marrow hyperplasia, iron overload, inflammation, and increased bone turnover. Bone metabolism is the result of balance maintenance between bone deposition and bone resorption, by osteoblasts (OBs) and osteoclasts (OCs). An impairment of this balance is responsible for the onset of bone diseases, such as osteoporosis (OP). Therefore, here we will discuss the alteration of bone metabolism in patients with hemoglobinopathies and the possible therapeutic strategies to contain and/or counteract bone health impairment in these patients, taking into consideration not only the pharmacological treatments already used in the clinical armamentarium, but also the new possible therapeutic strategies.

Engineered extracellular vesicles as therapeutics of degenerative orthopedic diseases

Degenerative orthopedic diseases, as a global public health problem, have made serious negative impact on patients' quality of life and socio-economic burden. Traditional treatments, including chemical drugs and surgical treatments, have obvious side effects and unsatisfactory efficacy. Therefore, biological therapy has become the focus of researches on degenerative orthopedic diseases. Extracellular vesicles (EVs), with superior properties of immunoregulatory, growth support, and drug delivery capabilities, have emerged as a new cell-free strategy for the treatment of many diseases, including degenerative orthopedic diseases. An increasing number of studies have shown that EVs can be engineered through cargo loading, surface modification, and chemical synthesis to improve efficiency, specificity, and safety. Herein, a comprehensive overview of recent advances in engineering strategies and applications of engineered EVs as well as related researches in degenerative orthopedic diseases, including osteoarthritis (OA), osteoporosis (OP), intervertebral disc degeneration (IDD) and osteonecrosis of the femoral head (ONFH), is provided. In addition, we analyze the potential and challenges of applying engineered EVs to clinical practice.

16S rDNA analysis of osteoporotic rats treated with osteoking

Introduction. Osteoporosis (OP) is characterized by microstructural degeneration of bone tissue, low bone mass, bone fragility and even brittle fracture (osteoporotic fracture, OPF). OP and OPF are common and there are many disadvantages to the current medications for OP/OPF. Osteoking is a traditional Chinese medicine (TCM) originating from the Yi nationality (Yunnan, China) that has been used to treat bone diseases for decades.Hypothesis/Gap Statement. This study will reveal the changes in the intestinal microbiota of OP rats after 70 days of osteoking treatment.Method. With duplication of sham and OP rats, eight groups were established, with six rats in each group. The intestinal microbiotas were analysed by 16S rDNA sequencing.Results. The results showed that osteoking changed the intestinal microbiota of sham rats and OP rats. The mechanism by which osteoking improves OP is related to the functions of the intestinal microbiota. After 70 days of treatment with osteoking, the contents of Pseudonocardia, Pedomicrobium, Variovorax, Niastella and Actinosynnema were decreased in OP rats. The functions of the above intestinal microbiota related to iron metabolism affected calcifediol and 25(OH)D, and measuring these bone metabolic indicators is required for further study.Conclusion. Osteoking changes the intestinal microbiota to improve OP, and further study which reveals these intestinal microbiota and mechanism is needed.

New Function of Cholesterol Oxidation Products Involved in Osteoporosis Pathogenesis

Osteoporosis (OP) is a systemic bone disease characterized by decreased bone strength, microarchitectural changes in bone tissues, and increased risk of fracture. Its occurrence is closely related to various factors such as aging, genetic factors, living habits, and nutritional deficiencies as well as the disturbance of bone homeostasis. The dysregulation of bone metabolism is regarded as one of the key influencing factors causing OP. Cholesterol oxidation products (COPs) are important compounds in the maintenance of bone metabolic homeostasis by participating in several important biological processes such as the differentiation of mesenchymal stem cells, bone formation in osteoblasts, and bone resorption in osteoclasts. The effects of specific COPs on mesenchymal stem cells are mainly manifested by promoting osteoblast genesis and inhibiting adipocyte genesis. This review aims to elucidate the biological roles of COPs in OP development, starting from the molecular mechanisms of OP, pointing out opportunities and challenges in current research, and providing new ideas and perspectives for further studies of OP pathogenesis.

CircFOXP1/FOXP1 promotes osteogenic differentiation in adipose-derived mesenchymal stem cells and bone regeneration in osteoporosis via miR-33a-5p

Osteoporosis (OP) is defined by bone mass loss and structural bone deterioration. Currently, there are no effective therapies for OP treatment. Circular RNAs (circRNAs) have been reported to have an important function in stem cell osteogenesis and to be associated with OP. Most circRNA roles in OP remain unclear. In the present study, we employed circRNA microarray to investigate circRNA expression patterns in OP and non‐OP patient bone tissues. The circRNA‐miRNA‐mRNA interaction was predicted using bioinformatic analysis and confirmed by RNA FISH, RIP and dual‐luciferase reporter assays. ARS and ALP staining was used to detect the degree of osteogenic differentiation in human adipose‐derived mesenchymal stem cells (hASCs) in vitro. In vivo osteogenesis in hASCs encapsulated in collagen‐based hydrogels was tested with heterotopic bone formation assay in nude mice. Our research found that circFOXP1 was significantly down‐regulated in OP patient bone tissues and functioned like a miRNA sponge targeting miR‐33a‐5p to increase FOXP1 expression. In vivo and in vitro analyses showed that circFOXP1 enhances hASC osteogenesis by sponging miR‐33a‐5p. Conversely, miR‐33a‐5p inhibits osteogenesis by targeting FOXP1 3′‐UTR and down‐regulating FOXP1 expression. These results determined that circFOXP1 binding to miR‐33a‐5p promotes hASC osteogenic differentiation by targeting FOXP1. Therefore, circFOXP7ay prevent OP and can be used as a candidate OP therapeutic target.

Prevalence and contributing factors of osteoporosis in the elderly over 70 years old: an epidemiological study of several community health centers in Shanghai

BACKGROUND

OP seriously affects the health status and quality of life of the elderly, even endangers life. This study aimed to investigate the prevalence and contributing factors of osteoporosis (OP) in the elderly over 70 years old of several Community Health Centers in Shanghai.

METHODS

A total of 565 elderly subjects were recruited and received questionnaire survey. The general characteristics, medical history and history of OP treatment were collected. Bone mineral density (BMD) was detected, and the awareness rate, prevalence and treatment rate were determined in all of the subjects. Moreover, activity of daily living and nutritional status were also evaluated. Logistic regression analysis was performed to calculate the OR and its 95% confidence interval. Bone turnover markers (BTMs) [procollagen type 1 N-peptide (P1NP), C-terminal cross-linked telopeptides of type 1 collagen (β-CTX), molecular fragment of N-terminal osteocalcin (N-MID), and 25 hydroxyvitamin D (25OHD)] were detected and their relationship with OP was further evaluated with Pearson correlation analysis.

RESULTS

: (I) The awareness rate of OP was 89.7%, the prevalence was 39.5%, and the treatment rate was 59.5% in the elderly over 70 years old of 4 Community Health Center in Shanghai; (II) the male gender and good nutritional status were independent protective factors of OP, and aging and poor activity of daily living were independent risk factors of OP; (III) β-CTX was negatively related to BMD (r=-0.286, P=0.000), but P1NP, N-MID, and 25OHD were positively related to BMD (r=0.254, 0.349 and 0.357, P=0.000, 0.000 and 0.000).

CONCLUSIONS

Female gender, aging, malnutrition, and inability to take care of themselves are risk factors of OP in people over 70 years old of 4 Community Health Centers in Shanghai. Some BTMs are related to the BMD. BTMs together with BMD may be used to comprehensively evaluate the bone state, identify the old people with OP at early stage, and guide the clinical treatment and early monitoring of OP.

Differential expression of genes associated with hypoxia pathway on bone marrow stem cells in osteoporosis patients with different bone mass index

Background

This study aimed to assess gene expression changes associated with hypoxia pathway on bone marrow stem cells (BMSCs) and explore effects of bone mass index (BMI) on hypoxia pathway of osteoporosis (OP) patients.

Methods

Human BMSCs were isolated from bone marrow. Subjects were divided into healthy control group and OP group which was further divided into BMI <25 OP subgroup and BMI ≥25 OP subgroup.

Results

The genes downregulated in OP patients were involved in hypoxia pathway. Furthermore, those genes were even downregulated in OP patients BMI ≥25 subgroup than OP patients BMI <25 subgroup. The genes were expressed in response to decreased oxygen levels, and their functions are related to photoperiodism, positive regulation of myoblast differentiation, and entrainment of circadian clock by gene ontology (GO) analysis.

Conclusions

The expression of genes associated with hypoxia pathway on BMSCs in OP patients are lower than healthy subjects, and the expression of genes related to carbohydrate metabolism are lower in overweight OP patients than in normal weight OP patients. These results need further research.