Cathepsin B and Muscular Strength are Independently Associated with Cognitive Control

Abstract

Although muscular strength has been linked to greater cognitive function across different cognitive domains, the mechanism(s) through which this occurs remain(s) poorly understood. Indeed, while an emerging body of literature suggests peripheral myokines released from muscular contractions may play a role in this relationship, additional research is needed to understand this link. Accordingly, this study sought to compare the influences of a particular myokine, Cathepsin B (CTSB), and muscular strength on hippocampal-dependent relational memory and cognitive control in 40 adults (age = 50.0±7.3 yrs). Overnight fasted venous blood draws were taken to assess plasma CTSB and muscular strength was assessed as maximal isokinetic strength testing using a Biodex dynamometer. Cognitive performance was assessed using a Spatial Reconstruction Task to assess relational memory and a modified Flanker task to assess cognitive control. Neuroelectric function for cognitive control was assessed using event-related potentials (ERPs) recorded during the Flanker task. Initial bivariate correlational analyses revealed that neither sex, age, lean body mass, or muscular strength was associated with CTSB. However, CTSB was inversely associated with reaction time and fractional peak latency of the P3 component of the Flanker task. Muscular strength was also inversely associated with reaction time and positively associated with relational memory performance. However, the influence of muscular strength on relational memory did not persist following adjustment for covariates. Greater circulating CTSB was selectively associated with greater cognitive control as well as faster information processing speed. These findings are the first to link circulating CTSB to both cognitive control and neuroelectric function. Future intervention studies are needed to examine the effects of changes in muscular strength, circulating myokines, and different domains of cognitive function.

Proceedings from the Albert Charitable Trust Inaugural Workshop on ‘Understanding the Acute Effects of Exercise on the Brain’

“…The benefits of exercise may be communicated to the brain via factors secreted from peripheral organs, comprehensively referred to as exerkines [113]. These include myokines [114,115] such as VEGF [116] irisin [117][118][119] and Cathepsin B [30,[120][121][122] as well as the myometabolite lactate [98]. In addition, hepatokines (insulin-like growth factor ( [123], clusterin [124], glycerophosphoryl diester phosphodiesterase-like protein [125]), adipokines [126], and blood platelets [127] derived from runners have been shown to play a role in neural plasticity or cognition [128][129][130].…”

Special Issue: Peripheral Factors and Neural Plasticity

“…In this study it was found that the latency of event related potentials an electrophysiological correlate of a cognitive task, the Flanker task, was inversely correlated with performance on the task. Thus, this study reports the novel finding that CTSB may play a role in cognitive control by modulating processing speed [ 8 ]. The final research paper pertains to effects of moderate-intensity exercise and high-intensity interval exercise on serum BDNF levels and working memory in young adult females.…”