Molecular changes in skeletal muscle in chronic kidney disease: A systematic review

Background

Loss of skeletal muscle mass is prevalent among patients affected by chronic kidney disease (CKD). It is associated with significant morbidity and mortality. The underlying molecular pathogenesis has yet to be fully understood. The aim of this systematic review is to summarize the current evidence on molecular changes in the skeletal muscle of humans and rodents with CKD and to assess the strength of such evidence.

Methods

The PubMed and EMBASE databases were searched using three main themes: messenger ribonucleic acid/protein/microRNA expression, skeletal muscle and CKD. This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards.

Results

A total of 98 studies were included in the systematic review, comprising 26 prospective human clinical studies, four human and rodent studies, and 68 rodent-only studies (32 mouse and 36 rat models respectively). The sample sizes of human studies were largely small (40% of studies had ≤20 participants). Qualitative polymerase chain reaction (qPCR) was the most commonly used method for gene expression and none of the studies fulfilled the Minimum Information for Publication of qPCR Experiments criteria for quality assessment. Majority of the studies investigated only a few genes or a specific signalling pathway. FBXO32, TRIM63, MSTN, IL6, TNF and IGF1 were the most investigated genes. The identified differentially expressed genes and proteins belonged to eight major pathways, including apoptosis, autophagy, inflammation, insulin/insulin-like growth factor 1 signalling, lipid metabolism, mitochondrial function, muscle cell growth and differentiation, and protein degradation, similar to other chronic disease states.

Conclusions

The current evidence regarding molecular alterations in the skeletal muscle in CKD is largely derived from small and heterogenous studies. Markedly similar modifications in the major biological pathways between CKD and other chronic diseases supports shared deleterious molecular mechanisms producing muscle atrophy, irrespective of the underlying specific disease.