Identification of three bacterial species associated with increased appendicular lean mass: the HUNT study

Limosilactobacillus reuteri 6475 and Prevention of Early Postmenopausal Bone Loss: A Randomized Clinical Trial

Importance

Daily supplementation with the probiotic Limosilactobacillus reuteri ATCC PTA 6475 (L reuteri) vs placebo has previously been demonstrated to reduce bone loss in an estrogen deficiency mice model and older women, although the magnitude of the effect was small. We hypothesized that long-term treatment with L reuteri could result in clinically relevant skeletal benefits in postmenopausal osteoporosis.

Objective

To evaluate whether daily supplementation with L reuteri vs placebo could reduce early postmenopausal bone loss and whether the effects remained or increased over time during 2 years of treatment.

Design, Setting, and Participants

A double-blind, randomized, placebo-controlled clinical trial was conducted between December 4, 2019, and October 6, 2022, at a single center in Gothenburg, southwestern Sweden. Participants were recruited by online advertisements, and letters were sent to 10 062 women aged 50 to 60 years. Responding women (n = 752) underwent telephone screening, resulting in 292 women being invited to a screening visit. Of those who were screened, 239 women met all inclusion criteria and had no exclusion criteria.

Interventions

Capsules with L reuteri in 2 doses, 5 × 108 (low dose) or 5 × 109 (high dose) colony-forming units, taken twice daily or placebo were administered. All capsules also included cholecalciferol, 200 IU.

Main Outcomes and Measures

The primary outcome was the relative change in tibia total volumetric bone mineral density (vBMD) over 2 years. Secondary outcomes included relative change in areal BMD of the lumbar spine and total hip, bone turnover markers C-terminal telopeptide cross-links of collagen type I and type I procollagen intact N-terminal propeptide, as well as tibia trabecular bone volume fraction and cortical vBMD. Both intention-to-treat and per-protocol analyses were conducted.

Results

A total of 239 postmenopausal women (median age, 55 [IQR, 53-56] years) were included. Tibia vBMD (primary outcome), hip and spine vBMD, and tibia cortical area and BMD decreased significantly in all groups, with no group-to-group differences (percent change tibia vBMD high dose vs placebo least-squares means, -0.08 [95 CI, -0.85 to 0.69] and low dose vs placebo least-squares means, -0.22 [95% CI, -0.99 to 0.55]). There were no significant treatment effects on any other predefined outcomes. A prespecified sensitivity analysis found a significant interaction between body mass index (BMI) and treatment effect at 2 years. No significant adverse effects were observed.

Conclusions and Relevance

In this randomized clinical trial of 239 early postmenopausal women, supplementation with L reuteri had no effect on bone loss or bone turnover over 2 years. The observed interaction between BMI and treatment effect warrants further investigation.

Trial Registration

ClinicalTrials.gov Identifier: NCT04169789.

Aminopeptidase O Protein mediates the association between Lachnospiraceae and appendicular lean mass

Objective

Investigating the causal relationship between Lachnospiraceae and Appendicular lean mass (ALM) and identifying and quantifying the role of Aminopeptidase O Protein (AOPEP) as a potential mediator.

Methods

The summary statistics data of gut microbiota composition from the largest available genome-wide association study (GWAS) meta-analysis conducted by the MiBioGen Consortium (n = 13,266). Appendicular lean mass data were obtained from the UK-Biobank (n = 450,243). We conducted bidirectional two-sample Mendelian randomization (MR) analysis using summary-level data from GWAS to investigate the causal relationship between Lachnospiraceae and ALM. Additionally, we employed a drug-targeted MR approach to assess the causal relationship between AOPEP and ALM. Finally, a two-step MR was employed to quantitatively estimate the proportion of the effect of Lachnospiraceae on ALM that is mediated by AOPEP. Cochran's Q statistic was used to quantify heterogeneity among instrumental variable estimates.

Results

In the MR analysis, it was found that an increase in genetically predicted Lachnospiraceae [OR = 1.031, 95% CI (1.011-1.051), P = 0.002] is associated with an increase in ALM. There is no strong evidence to suggest that genetically predicted ALM has an impact on Lachnospiraceae genus [OR = 1.437, 95% CI (0.785-2.269), P = 0.239]. The proportion of genetically predicted Lachnospiraceae mediated by AOPEP was 34.2% [95% CI (1.3%-67.1%)].

Conclusion

Our research reveals that increasing Lachnospiraceae abundance in the gut can directly enhance limb muscle mass and concurrently suppress AOPEP, consequently mitigating limb muscle loss. This supports the potential therapeutic modulation of gut microbiota for sarcopenia. Interventions such as drug treatments or microbiota transplantation, aimed at elevating Lachnospiraceae abundance and AOPEP inhibition, synergistically improve sarcopenia in the elderly, thereby enhancing the overall quality of life for older individuals.

Association of skeletal muscle function, quantity, and quality with gut microbiota in Japanese adults: A cross-sectional study

AIM

The gut microbiota has emerged as a new intervention target for sarcopenia. Prior studies in humans have focused on the association between gut microbiota and skeletal muscle quantity, while the evidence on muscle function and quality is lacking. This study aimed to identify gut microbiota genera associated with skeletal muscle function, quantity, and quality in a general population of Japanese adults.

METHODS

This cross-sectional study included 164 participants aged 35-80 years, women and men recruited from urban areas of Japan. Fecal samples were collected and analyzed using 16S rRNA gene amplicon sequencing. Skeletal muscle function was measured using handgrip strength and leg extension power (LEP), while skeletal muscle mass was estimated using bioelectrical impedance analysis. Phase angle was used as a measure of skeletal muscle quality. Multivariate linear regression analysis stratified by age group was used to examine the association between the dominant genera of the gut microbiota and skeletal muscle variables.

RESULTS

A significant association was found between Bacteroides and Prevotella 9 with LEP only in the ≥60 years group. When both Bacteroides and Prevotella 9 were included in the same regression model, only Bacteroides remained consistently and significantly associated with LEP. No significant associations were observed between skeletal muscle mass, handgrip strength, and phase angle and major gut microbiota genera.

CONCLUSIONS

In this study, we observed a significant positive association between Bacteroides and leg muscle function in older adults. Further studies are required to elucidate the underlying mechanisms linking Bacteroides to lower-extremity muscle function. Geriatr Gerontol Int 2024; 24: 53-60.