Targeting lysophospholipid signaling as a therapeutic approach towards improved peripheral nerve regeneration

Plasma sphingosine 1-phosphate concentrations and cardiovascular autonomic neuropathy in individuals with type 2 diabetes

The aim of this study was to test the hypothesis that plasma sphingosine 1-phosphate (S1P) levels are associated with the risk of cardiovascular autonomic neuropathy (CAN) in type 2 diabetes patients. This cross-sectional study included 287 individuals with type 2 diabetes. CAN was evaluated using cardiovascular reflex tests. Logistic regression analyses were conducted to assess the relationship between plasma S1P levels and CAN. Plasma S1P concentrations were significantly lower in individuals with CAN than in those without CAN. There was a significant interaction between plasma S1P levels and sex with respect to CAN (p for interaction = 0.003). When stratified by sex, the association between plasma S1P levels and CAN exhibited a sex difference; in multivariable analysis, plasma S1P levels were significantly associated with CAN in women (odds ratio per standard deviation increase in the log-transformed value, 0.40; 95% confidence interval, 0.23–0.70, p = 0.001). However, there was no significant association between plasma S1P and CAN in men. Plasma S1P concentrations were inversely associated with CAN only in women with type 2 diabetes.

Analysis of transcriptome sequencing of sciatic nerves in Sprague-Dawley rats of different ages

An aging-induced decrease in Schwann cell viability can affect regeneration following peripheral nerve injury in mammals. It is therefore necessary to investigate possible age-related changes in gene expression that may affect the biological function of peripheral nerves. Ten 1-week-old and ten 12-month-old healthy male Sprague-Dawley rats were divided into young (1 week old) and adult (12 months old) groups according to their ages. mRNA expression in the sciatic nerve was compared between young and adult rats using next-generation sequencing (NGS) and bioinformatics (n = 4/group). The 18 groups of differentially expressed mRNA (DEmRNAs) were also tested by quantitative reverse transcription polymerase chain reaction (n = 6/group). Results revealed that (1) compared with young rats, adult rats had 3608 groups of DEmRNAs. Of these, 2684 were groups of upregulated genes, and 924 were groups of downregulated genes. Their functions mainly involved cell viability, proliferation, differentiation, regeneration, and myelination. (2) The gene with the most obvious increase of all DEmRNAs in adult rats was Thrsp (log₂ FC = 9.01, P < 0.05), and the gene with the most obvious reduction was Col2a1 (log₂FC = –8.89, P < 0.05). (3) Gene Ontology analysis showed that DEmRNAs were mainly concentrated in oligosaccharide binding, nucleotide-binding oligomerization domain containing one signaling pathway, and peptide-transporting ATPase activity. (4) Analysis using the Kyoto Encyclopedia of Genes and Genomes showed that, with increased age, DEmRNAs were mainly enriched in steroid biosynthesis, Staphylococcus aureus infection, and graft-versus-host disease. (5) Spearman's correlation coefficient method for evaluating NGS accuracy showed that the NGS results and quantitative reverse transcription polymerase chain reaction results were positively correlated (r_s = 0.74, P < 0.05). These findings confirm a difference in sciatic nerve gene expression between adult and young rats, suggesting that, in peripheral nerves, cells and the microenvironment change with age, thus influencing the function and repair of peripheral nerves.