Evidence for a Potential “Knee-Eye-Brain Axis” Involved in Mobility and Navigation Control: Knee Injury and Obesity May Disrupt Axis Integrity

摘要

Humans depend on the coordinated activity of their lower extremities for mobility, an essential feature of Homo sapiens. In addition, they use vision to use this mobility to successfully navigate through their environment. During development, mobility appears to mature first, and then it is coordinated with navigation. Thus, the two, mobility and navigation are likely interdependent in function. Recent studies have indicated that compromising the integrity of the knee, a central element of the lower extremity motion segment, can lead to molecular alterations in both the cornea including the central cornea where light passes, as well as the interior of the eye (the vitreous humor). Not all insults to the knee lead to reproducible alterations in the eye, indicating some specificity in the response. In addition, it was recently reported that alterations to the cells in the vitreous humor occur following dietary induction of obesity in a rat model. As humans with obesity, as well as arthritis of the knee are at risk for ocular involvement and exhibit altered gait characteristics, the clinical and preclinical data raise the possibility of a “knee-eye-brain axis” to control or regulate mobility and navigation. Better delineation of such an axis could have implications for variations in control during maturation, and well as during aging when vision and mobility can be compromised, with increased risk for serious falls and failure to successfully navigate the environment.