Epidermal lipid homeostasis is crucial for skin barrier integrity. This study investigated the effects of an aqueous extract from Beta vulgaris subsp. vulgaris Beetroot Group (BvE) on stress responses and lipid metabolism in HaCaT keratinocytes. BvE, obtained from leaves grown in SETIS^® bioreactors as a standardized biomass source, was chemically characterized by ¹H NMR and ¹³C NMR. HaCaT cells were treated with BvE (1 µg/mL), H₂O₂, or palmitic/oleic acids (PA/OA) to evaluate its protective effects against oxidative damage and lipotoxic stress. Under these conditions, BvE exhibited a distinctive dual action as a reactive oxygen species (ROS) scavenger and triacylglycerol (TAG)-lowering agent. On the one hand, BvE was associated with decreased intracellular ROS levels and changes in NRF2 protein expression, suggesting involvement of redox-regulatory pathways. On the other hand, it was associated with attenuation of lipotoxicity, as evidenced by reduced lipid droplet (LD) formation and decreased expression of DGAT1 and PLIN2. Furthermore, these effects were accompanied by a reduction in Unfolded Protein Response (UPR) markers, modulation of AMPK-associated signaling, attenuation of mitochondrial disfunction, and decreased p53 phosphorylation, findings collectively consistent with a coordinated cytoprotective response. In conclusion, BvE shows potential to protect keratinocytes against lipotoxicity and oxidative stress through mechanisms that may involve both chemical and biological antioxidant activity and metabolic reprogramming, supporting its further investigation for dermatological applications.

Lactate was traditionally considered a metabolic by-product of anaerobic glycolysis, mainly associated with tissue hypoxia and muscle fatigue. However, increasing evidence has redefined lactate as a multifunctional metabolic intermediate and signaling molecule involved in exercise-induced systemic adaptations. During physical activity, circulating lactate levels rise markedly when skeletal muscle production exceeds systemic clearance, allowing lactate to act as an exercise-responsive metabolite, or exerkine, and as a mediator of cardiometabolic adaptation. In the cardiovascular system, lactate serves not only as an efficient substrate for myocardial energy production but also as a regulator of vascular tone, endothelial function, angiogenesis, inflammation, and cardiac remodeling. These effects occur through receptor-dependent and receptor-independent mechanisms, including activation of hydroxycarboxylic acid receptor 1 (HCAR1/GPR81), modulation of intracellular redox balance, and histone or non-histone protein lactylation. This review summarizes current evidence on lactate in cardiovascular physiology and disease, focusing on myocardial lactate metabolism, HCAR1/GPR81 signaling, protein lactylation, extracellular vesicle communication, gut microbiota interactions, and therapeutic implications in heart failure, atherosclerosis, and diabetic cardiomyopathy. Although lactate is also produced under resting, postprandial, and pathological conditions, exercise is characterized by the amplitude and kinetics of lactatemia, coordinated hormonal and hemodynamic responses, and transient high-concentration signaling. These features support exercise-derived lactate as a context-dependent cardiovascular exerkine.