Association of blood n-3 fatty acid with bone mass and bone marrow TRAP-5b in the elderly with and without hip fracture

Er-Xian decoction attenuates ovariectomy-induced osteoporosis by modulating fatty acid metabolism and IGF1/PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Er-Xian decoction (EXD) is a traditional Chinese medicine (TCM) formula used to treat osteoporosis (OP). However, the anti-OP mechanism of EXD has not yet been fully elucidated.

AIM OF THE STUDY

The study aimed to verify the anti-OP effect of EXD and to explore its underlying mechanism.

METHODS

The anti-OP targets and mechanisms of EXD were predicted by network pharmacological analysis. Then, an ovariectomized (OVX) rat model was established to validate the key anti-OP mechanism of EXD. Firstly, the therapeutic effect of EXD on OP was confirmed using micro-CT bone analysis, pathological observation, and ELISA detection. Secondly, serum metabolites related to key biological processes were detected using an automatic biochemical analyzer and GC-MS. Finally, ELISA, qRT-PCR, and western blot were utilized to further explore the potential key anti-OP pathway of EXD.

RESULTS

A total of 159 anti-OP targets of EXD were identified. Functional annotation revealed that OP treatment using EXD was associated with lipid metabolism, fatty acid (FA) metabolism, and PI3K/AKT signaling pathway. Experimental studies confirmed that EXD ameliorated ovariectomy-induced bone loss and bone microstructure deterioration. EXD treatment also upregulated the level of serum estrogen and downregulated the level of OC, PⅠNP, CTX-1, TC, and LDL-C. Besides, principal component analysis (PCA) and heat map of serum FAs distinguished OVX rats from the SHAM and EXD groups. Serum concentrations of important n-3 FAs, including C20:3N3, C20:5N3, and C22:5N3, were significantly increased in the EXD group. The increased stearoyl-CoA desaturase 1 (SCD1) index 1 and index 2 in the OVX group were reversed by EXD administration. Additionally, EXD reversed the decreased serum IGF1 level and tibia IGF1R, PI3K, and AKT expression in OVX rats.

CONCLUSION

EXD ameliorated ovariectomy-induced bone loss by modulating lipid metabolism, FA metabolism, and IGF1/PI3K/AKT pathway.

Associations of long chain polyunsaturated fatty acids with bone mineral density and bone turnover in postmenopausal women

PURPOSE

The immunomodulatory properties of n-3 long chain polyunsaturated fatty acids (LCPUFA) are reported to reduce bone loss through alteration of bone remodelling and n-3 LCPUFA, therefore, may benefit bone health in post-menopausal women, a vulnerable group at high risk of osteoporosis.

METHODS

Measures of bone mineral density (BMD) were determined using dual energy X-ray absorptiometry (DEXA) in 300 post-menopausal women. The bone turnover markers osteocalcin (OC), C-terminal telopeptides of type 1 collagen (CTX) and total alkaline phosphatase were quantified in serum along with urinary creatinine corrected deoxypyridinoline (DPD/Cr) and CTX/Cr and the CTX:OC ratio calculated. Total serum n-6 PUFA (LA + AA) and n - 3 LCPUFA (ALA + EPA + DPA + DHA) were measured and the n - 6:n - 3 ratio was calculated.

RESULTS

Mean (SD) age and body mass index (BMI) were 61 (6.4) years and 27.4 (4.8) kg/m², respectively with participants being 12.6 (7.6) years post-menopause. Multiple regression analysis identified no association between n-3 LCPUFA and any of the measures of T-score or BMD albeit a significant positive association between total n - 3 LCPUFA and femur BMD (β = 0.287; p = 0.043) was observed within those women with a low n - 6:n - 3 ratio. There was a significant inverse association between ALA and urinary DPD/Cr (β = - 0.141; p = 0.016).

CONCLUSION

A favourable low n - 6:n - 3 ratio was associated with higher femur BMD and a higher n - 3 LCPUFA (ALA) was associated with lower bone resorption. These results support a beneficial role for n - 3 LCPUFA in reducing postmenopausal bone resorption and favourably influencing BMD.

TRIAL NUMBER & DATE OF REGISTRATION

ISRCTN63118444, 2nd October 2009, "Retrospectively registered".

Lower Serum n-3 Fatty Acid Level in Older Adults with Sarcopenia

The n-3 fatty acid (FA) has evoked considerable interest as a modifiable factor for maintenance of muscle health owing to its anti-inflammatory properties. To clarify this possibility, we investigated circulating n-3 FA level, a reliable biomarker of FA status in the body, in relation to sarcopenia in a cohort of Asian older adults. Blood samples were collected from 125 participants who underwent comprehensive assessment of muscle mass and function. Serum FA level was measured by gas chromatography/mass spectrometry. Sarcopenia was diagnosed using the cut-off points specified for the Asian population. After adjusting for sex, age, and body mass index, subjects with sarcopenia and those with low muscle strength had 36.5% and 32.4% lower serum n-3 levels (P = 0.040 and 0.030), respectively, than controls. The odds ratios per standard deviation increment in serum n-3 level for sarcopenia and low muscle strength were 0.29 and 0.40 (P = 0.015 and 0.028), respectively. A higher serum n-3 level was significantly associated with greater muscle strength (P = 0.038). These findings suggest a possible protective effect of n-3 FA on human muscle homeostasis. Further well-designed large-scale longitudinal studies are necessary to understand the definite role of circulating n-3 FA level in sarcopenia risk assessment.