Chronic inflammatory cartilage biomarkers in athletes from different sports. Interpreting acute and chronic response to exercise from several inflammatory biomarkers: a review; Correlation between chronic inflammatory biomarkers in male athletes from ultra-running, rugby and cross-training.

Abstract

Algumas proteínas encontradas no sangue, têm vindo a assumir um papel extremamente relevante na resposta inflamatória cartilagínea correlacionada com a prática de exercício físico intenso. O primeiro objetivo deste estudo, é resumir todas as publicações que já estudaram biomarcadores cartilagíneos durante os últimos cinco anos (2015-2020). Haverá uma especial atenção à análise da resposta crónica de cada um dos destes e à sua consequente correlação com a prática intensa e diária de exercício físico.Seguidamente, durante a parte experimental do estudo, será analisada ainda a concentração de COMP, IL1-ra, TNF-α, IL-6 e IL-10 de um grupo de 62 atletas profissionais de 3 diferentes desportos; cross-training (N=21); ultra-running (N= 15) e rugby (N= 26).Com este trabalho, foi possível concluir que há um grande desconhecimento sobre quais as influências crónicas da prática de exercício físico intenso, no que toca à concentração de biomarcadores da destruição da cartilagem. A comunidade científica está hoje mais focada na resposta aguda destes biomarcadores. Ainda assim, podemos perceber que existe uma correlação positive entre a concentração crónica de COMP e a prática de exercício físico a um nível profissional. Também é possível levantar a hipótese que poderá existir uma correlação entre a prática de exercício físico a um nível profissional e o desenvolvimento de OA ou RA, no futuro. Ainda assim, é necessário desenvolver mais estudos nesta área para de forma a haver uma confirmação.

A specific group of serum cytokines are already being studied as possible indicators to analyse joint cartilage inflammation. Analysing these proteins has been demonstrated to give a good indication of cartilage breakdown and metabolism. Cytokines are a generic name given to small proteins that are released by cells and control communication and interaction between them. It is possible to categorise cytokines into four different types. Lymphokines are cytokines produced by lymphocytes; monokines are produced by monocytes; chemokines produce a specific chemotactic response and, finally, interleukins are made in one leukocyte but act on another. Cytokines are non-specific, meaning that various cytokines can stimulate the same activity or function. Cytokines are mainly produced in helper T cells or macrophages; however, they can also be produced by other cells. It is possible to categorise them as either pro or anti-inflammatory. Activated macrophages usually produce pro-inflammatory cytokines involved in the upregulation of inflammatory reactions. For example, IL-1β or TNF-α, both of which are involved in the process of pathological pain. Anti-inflammatory cytokines, however, are molecules that play an essential role during the regulation of pro-inflammatory cytokines. It is also possible to categorise some specific cytokines, e.g. IL-6 or even TGF-β as a pro or even anti-inflammatory, depending on various external circumstances. IL-1 receptor antagonists (IL-1ra), IL-4, IL-10, IL-11 and IL-13 are the most well studied anti-inflammatory cytokines. Blood or serum biomarkers assume an exciting strategy to understand better the eventual correlations between the intense practice of some sports and the possibility to develop different chronic diseases such as osteoarthritis (OA) or rheumatoid arthritis (RA). The primary goal of this study is, to sum up, all the studies focused on cartilage biomarkers during the last five years. Mainly, it will be analysed the acute and chronic response that each specific biomarker has when an exercise inducement is made. During the experimental part, a group of sixty-two healthy high-level male athletes from different sports, such as cross-training (N = 21); ultra-running (N = 15) and rugby (N = 26), were anthropometrically and physiologically evaluated.It is possible to conclude that there is a fundamental lack of knowledge surrounding the basal concentration of some inflammatory cartilage biomarkers. The scientific community is mainly focused on studying the acute responses of these inflammatory biomarkers. It is possible to note the correlation between the COMP concentration and sport at the professional level. Thus, it is possible to hypothesise that exercise can result in RA or OA in the future. Yet, it is still very much necessary to conduct further studies to prove this.