Effects of Hydrolyzed Collagen as a Dietary Supplement on Fibroblast Activation: A Systematic Review.

BACKGROUND: Our objective was to conduct a systematic review of the effects of hydrolyzed collagen supplementation on the proliferation and activation of fibroblasts. METHODS: The search was conducted for journals that published articles in the English language, peer-reviewed, meeting the following criteria: (a) randomized clinical trials, (b) randomized studies in animals or humans, (c) in vitro studies, (d) studies using hydrolyzed collagens or collagen peptides, and (e) studies assessing alterations on fibroblasts as the primary or secondary outcome. We utilized the main journal databases PubMed/Web of Science and ongoing reviews by PROSPERO. For bias risk and methodological quality, we used an adaptation of the Downs and Black checklist. Our review followed the PRISMA checklist, conducted from February 2024 to the first week of March 2024, by two independent researchers (P.A.Q.I. and R.P.V.). RESULTS: Eleven studies were included in this review, where our findings reinforce the notion that hydrolyzed collagens or collagen peptides at concentrations of 50-500 µg/mL are sufficient to stimulate fibroblasts in human and animal tissues without inducing toxicity. Different enzymatic processes may confer distinct biological properties to collagens, allowing for scenarios favoring fibroblast promotion or antioxidant effects. Lastly, collagens with lower molecular weights exhibit greater bioavailability to adjacent tissues. CONCLUSIONS: Hydrolyzed collagens or collagen peptides with molecular sizes ranging from <3 to 3000 KDa promote the stimulation of fibroblasts in human tissues.

Exerkines: A Crosstalk between Lactate Production, Exercise and Mental Health.

Muscle skeletal striated cells secrete a wide range of proteins called myokines or "exerkines", which in turn perform autocrine, paracrine, or endocrine functions. For being able to act in the communication between skeletal muscle, adipose tissue, and mainly the brain, exerkines play a prominent role and potential influence on health promotion. Furthermore, we detected in the literature that one of these potential therapeutic substances derived from muscle contraction is a molecule derived from glycolytic metabolism that in the past was largely marginalized, the lactate. Currently, studies are dedicated to examining the target structures for exerkines that may contribute to the maintenance and restoration of mental health. Thus, lactate appears to be recognized as a critical mediator of exercise-related changes and their health benefits, particularly in their role in communication and coordination between organs. It is inferred that the BDNF expression mechanism can be induced by lactate, which in turn derives from the activation of SIRT pathways 1 and 2 and activates the PGC1-α cascade. The behavior of lactate concentration is intensity-dependent, directly related to the type of fast-twitch fibers (type IIb) and the recruitment of these fibers would potentiate the responses in the brain. In this sense, high-intensity exercise would establish itself as an important strategy to be considered. Despite this understanding, there is still much to be done. However, lactate appears to be a highly promising exerkine for future research initiatives and a potential biomarker to reduce illness and promote mental health.