[Primary and secondary osteoporosis. The important role of internal medicine in its differential diagnosis]

Identification of association between rs1057317 polymorphism in TLR4 3'-untranslated region and the susceptibility to osteoporosis

It has been proved that the expression of TLR4 is associated with a reduced risk of osteoporosis (OP). One single-nucleotide polymorphism located within the 3'-untranslated region (3'-UTR) of TLR4 may "generate" binding site of miR-34a and thereby associated with risk of OP. Bioinformatics analysis and luciferase reporter assay were used to specify the effect of polymorphisms on the interaction between miR-34a and TLR4 gene. Western blot analysis and real-time polymerase chain reaction were used to study the expressions of miR-34a, TLR4 in different groups or cells transfected with miR-34a mimics or inhibitor. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to estimate the effect of miR-34a on the apoptosis of osteoblast. TLR4 was identified as a target of miR-34a, with negative regulatory relationship predicted. The expression levels of miR-34a was comparable with each other between CC, CA, and AA groups, and the expression levels of TLR4 was evidently lower in CC compared with GG and GC groups. Also, TLR4 level in culture osteoblast (genotyped as CC) treated with miR-34a mimics was substantially downregulated compared with scramble control, while those cells (genotyped as CC) treated with miR-34a inhibitors showed increased expression of TLR4. Additionally, the apoptosis of osteoblast genotyped as CC was decreased following transfection with miR-34a mimics, while evidently promoted subsequent to transfect with miR-34a inhibitor. The regulatory association between rs1057317 polymorphism in TLR4 3'-UTR led to an inhibitory effect on the expression of TLR4 by miR-34a, which may explain the observed association between the polymorphism and the susceptibility to OP.

Presenting a Method to Improve Bone Quality Through Stimulation of Osteoporotic Mesenchymal Stem Cells by Low-Level Laser Therapy

OBJECTIVE

This review aims to present a method to improve bone quality through stimulation of osteoporotic mesenchymal stem cells (MSCs) by low-level laser therapy (LLLT).

BACKGROUND

Osteoporosis (OP) is characterized by decreased bone mass and bone strength, which results in an increased incidence of bone fractures. These fractures often lead to additional disability and mortality. Osteoporotic MSCs have reduced osteogenic differentiation when cultured in their standard differentiation media. LLLT has a biostimulatory effect on fibroblasts and osteoblasts. MSCs have the ability to generate cells of connective tissue lineages, which includes the bones. Recently, transplantation of in vitro cultured bone marrow (BM) MSCs into sites at risk for development of osteoporotic bone has resulted in improved bone structure.

METHODS

Comprehensive research was performed using PubMed, and biostimulatory effect of LLLT on bony cells and MSCs were studied.

RESULTS

LLLT can stimulate growth, proliferation, and differentiation of SCs in vitro and in vivo. This ability of LLLT is an essential prerequisite for performing experiments related to disease control in humans. Thus, laser-treated osteoporotic autologous BMMSCs may represent a promising therapeutic method to protect the bones in patients with OP and prevent fractures in these patients. Therefore, researchers hypothesize that transplantation of in vitro laser-treated autologous cultured osteoporotic BMMSCs that have the appropriate osteogenic phenotype into sites at risk for development of osteoporotic bone may result in improved bone structure. In this respect, investigators have successfully used LLLT to restore autologous osteoporotic MSCs in vitro. Subsequently, these cells have been differentiated into osteoblast cell lines with the use of laser treatment after which they were transplanted into osteoporotic animal models.

CONCLUSIONS

This technique might improve bone quality and structure. However, additional research must be undertaken to understand the underlying mechanisms of this treatment, validate its effectiveness, and assess the feasibility for clinical application of LLLT to treat MSCs in regeneration of osteoporotic bone.

[Osteomalacia and vitamin D deficiency]

BACKGROUND

Vitamin D and calcium deficiency has a higher incidence in the orthopedic-trauma surgery patient population than generally supposed. In the long term this can result in osteomalacia, a form of altered bone mineralization in adults, in which the cartilaginous, non-calcified osteoid does not mature to hard bone.

AIM

The current value of vitamin D and its importance for bones and other body cells are demonstrated.

RESULTS

The causes of vitamin D deficiency are insufficient sunlight exposure, a lack of vitamin D3 and calcium, malabsorption, and rare alterations of VDR signaling and phosphate metabolism. The main symptoms are bone pain, fatigue fractures, muscular cramps, muscle pain, and gait disorders, with an increased incidence of falls in the elderly. Osteopathies induced by pharmaceuticals, tumors, rheumatism or osteoporosis have to be considered as the main differential diagnoses.

CONCLUSIONS

In addition to the recording of symptoms and medical imaging, the diagnosis of osteomalacia should be ensured by laboratory parameters. Adequate treatment consists of the high-dose intake of vitamin D3 and the replacement of phosphate if deficient. Vitamin D is one of the important hormone-like vitamins and is required in all human cells. Deficiency of vitamin D has far-reaching consequences not only for bone, but also for other organ systems.

Methionine down-regulates TLR4/MyD88/NF-κB signalling in osteoclast precursors to reduce bone loss during osteoporosis

BACKGROUND AND PURPOSE

Studies have demonstrated that a moderate intake of amino acids is associated with development of bone health. Methionine, a sulphur-containing essential amino acid, has been largely implicated for improving cartilage formation, however its physiological significance on bone integrity and functionality have not been elucidated. We investigated whether methionine can prevent osteoporotic bone loss.

EXPERIMENTAL APPROACH

The anti-resorptive effect of methionine, (250 mg kg(-1) body wt administered in drinking water for 10 weeks), was evaluated in ovariectomized (OVX) rats by monitoring changes in bone turnover, formation of osteoclasts from blood-derived mononuclear cells and changes in the synthesis of pro-osteoclastogenic cytokines.

KEY RESULTS

Methionine improved bone density and significantly decreased the degree of osteoclast development from blood mononuclear cells in OVX rats, as indicated by decreased production of osteoclast markers tartarate resistant acid phosphatase b (TRAP5b) and MIP-1α. siRNA-mediated knockdown of myeloid differentiation primary response 88 [MyD88], a signalling molecule in the toll-like receptor (TLR) signalling cascade, abolished the synthesis of both TRAP5b and MIP-1α in developing osteoclasts. Methionine supplementation disrupted osteoclast development by inhibiting TLR-4/MyD88/NF-κB pathway.

CONCLUSIONS AND IMPLICATIONS

TLR-4/MyD88/NF-κB signalling pathway is integral for osteoclast development and this is down-regulated in osteoporotic system on methionine treatment. Methionine treatment could be beneficial for the treatment of postmenopausal osteoporosis.

[Reality of treatment of osteoporotic fractures in German trauma departments. A contribution for outcome research]

The implementation of clinical pathways has a proven positive effect on the diagnostic workup and initiation of therapy in osteoporotic fracture patients. Unlike in most countries, fracture care in Germany is provided by so-called trauma surgeons. Therefore, it is essential to focus on the trauma surgeon for correct diagnostic workup and therapy initiation after a fragility fracture. A questionnaire was mailed to 409 departments of traumatology inquiring about the existence of a standardized clinical pathway for diagnosis and treatment of patients with fragility fractures. One of the central issues of the survey was whether those pathways comply with national guidelines. Only institutions that stated that they followed a clinical pathway were analyzed. 80% of institutions took part in our survey, 35% of which reported following a defined clinical pathway. Diagnostic workup is in concordance with the national guidelines in 30%, and therapy is guideline-based in 51%, with 12% basing both diagnostic workup and therapy on the guidelines. Thus, the vast majority of German traumatology departments do not follow national guidelines regarding osteoporosis diagnostics and therapy in patients with fragility fractures, leading to a great opportunity to improve fragility fracture care by means of both education and interdisciplinary cooperation.

[Metabolic bone diseases]

Osteomalacia is caused by impaired vitamin D receptor (VDR) signaling, calcium deficiency, and altered bone mineralization. This can be due to insufficient sunlight exposure, malabsorption, reduced D hormone activation in chronic kidney disease, and rare alterations of VDR signaling and phosphate metabolism. Leading symptoms are bone pain, muscular cramps, and increased incidence of falls in the elderly. The adequate respective countermeasures are to optimize the daily intake of calcium and vitamin D3 and to replace active D hormone and phosphate if deficient. Osteoporosis is characterized by bone fragility fractures upon minor physical impact. Indications for diagnosis and treatment can be established by estimating the absolute fracture risk, taking into account bone mineral density, age, gender, and individual risk factors. Exercise, intervention programs to avoid falls, and specific drugs are capable of substantially reducing fracture risk even in the elderly. Secondary osteoporosis primarily requires both bone-altering medications and effective treatment of underlying diseases.

Prävention der Osteoporose – wichtig für den Urologen?

Osteoporosis is a systemic disease of the bones with increasing incidence in the elderly. Over the age of 50 years bone mineral density continuously decreases resulting in osteoporotic fracture. Osteoporosis is positively correlated with late-onset hypogonadism and increases under androgen deprivation therapy. The evaluation of osteoporosis should be done in cooperation with an endocrinologist. Measurement of bone mineral density is recommended before starting androgen deprivation therapy. Patients with fracture and/or decreased bone mineral density 2.5 or more standard deviations below normal peak bone mass of young men should be treated. The appropriate treatment is calcium and vitamin D substitution combined with oral or i.v. administration of bisphosphonates.