Tao Huang

This paper presents a systematic review of studies investigating the effects of fatty acid supplementation in potentially preventing and treating sarcopenia. PubMed, Embase, and Web of Science databases were searched using the keywords ‘fatty acid’ and ‘sarcopenia’. Results: A total of 14 clinical and 11 pre-clinical (including cell and animal studies) studies were included. Of the 14 clinical studies, 12 used omega-3 polyunsaturated fatty acids (PUFAs) as supplements, 1 study used ALA and 1 study used CLA. Seven studies combined the use of fatty acid with resistant exercises. Fatty acids were found to have a positive effect in eight studies and they had no significant outcome in six studies. The seven studies that incorporated exercise found that fatty acids had a better impact on elderlies. Four animal studies used novel fatty acids including eicosapentaenoic acid, trans-fatty acid, and olive leaf extraction as interventions. Three animal and four cell experiment studies revealed the possible mechanisms of how fatty acids affect muscles by improving regenerative capacity, reducing oxidative stress, mitochondrial and peroxisomal dysfunctions, and attenuating cell death. Conclusion: Fatty acids have proven their value in improving sarcopenia in pre-clinical experiments. However, current clinical studies show controversial results for its role on muscle, and thus the mechanisms need to be studied further. In the future, more well-designed randomized controlled trials are required to assess the effectiveness of using fatty acids in humans.

Background The detrimental effect of prolonged cold ischemia time (PCI) on presensitized transplanted graft is conceivable, but the impact of presensitization status of recipient on PCI-mediated graft injury and inflammation is not well defined. Methods Allogeneic skin grafts from BALB/c donors were transplanted into C57BL/6 recipients for presensitization. Syngeneic or allogeneic heterotopic heart transplantations with PCI were performed using C57BL/6 or BALB/c donors for these recipients through different treatments. Results We revealed that PCI could not affect isograft survival but significantly shortened allograft survival in the presensitized recipients. Depletion of regulatory T cells (Tregs) starting 1 day before and after heart transplantation with anti-CD25 monoclonal antibody remarkably induced intragraft Foxp3 gene expression, worsened architecture damage and subepicardial and intramuscle inflammatory cellular infiltration, and caused a dramatic fall of intragraft CD4⁺/CD8⁺ ratio, whereas adoptive transfer of exogenous wild-type Tregs or endogenous Tregs promoted by rapamycin had a beneficial effect on preventing the infiltration of T lymphocytes and Gr-1⁺ neutrophils and reversed intragraft CD4⁺/CD8⁺ ratio, preserving cardiac graft architecture. However, their distinct protective mechanisms showed that rapamycin treatment mainly diminished CD4⁺ T-cell infiltration. Nevertheless, CD4⁺ still outnumbered CD8⁺ T cells in the graft, whereas adoptive transfer of Tregs expanded both CD4⁺ and CD8⁺ T cells, particularly CD8⁺ T cells. Conclusion Allogeneic immunoresponses synergistically enhanced PCI effect under presensitized condition. PCI could affect subsequent immunoresponses. Tregs were closely involved in this pathophysiologic process. Our data may pave the way to use Tregs as a novel therapeutic approach to prevent PCI-mediated injury in the presensitized transplant recipients.