Carnosine as a Protective Agent of Cardiac Muscle Tissue: Advances Toward Its Therapeutic Use

• Grant number: 25/24772-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: December 01, 2025
• End date: May 31, 2027
• Field of knowledge: Health Sciences - Nutrition - Nutrition Biochemistry
• Principal Investigator: Guilherme Giannini Artioli
• Grantee: Andressa Formalioni
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 24/18769-3 - Carnosine as a protective agent in cardiac muscle tissue: advances towards its therapeutic use, AP.R

Abstract

Carnosine is a dipeptide naturally synthesized in excitable tissues, particularly in striated muscles, and can also be obtained through the diet, although its bioavailability is limited due to degradation by carnosinases present in the gastrointestinal tract and bloodstream. This compound exhibits a wide range of physiological and biochemical properties that confer both therapeutic and ergogenic potential, including intracellular pH regulation, antioxidant activity, protection against protein glycation and carbonylation, and detoxification of aldehydes generated by lipid peroxidation.Our research group has developed a novel knockout rat strain for the CARNS1 gene, which encodes carnosine synthase, enabling the direct investigation of the physiological roles of this dipeptide. These carnosine-deficient animals have revealed a crucial role of the molecule in modulating cardiac function, mainly through the regulation of calcium (Ca²¿) transients. Based on these findings, the present project aims to investigate the protective role of carnosine in cardiac tissue under physiological stress conditions induced by doxorubicin, a chemotherapeutic agent known for its cardiotoxic effects.To test the hypothesis of myocardial protection, four experimental groups will be established: CARNS1¿/¿ rats (lacking carnosine), CARNS1¿/¿ rats (normal carnosine levels), CARNS1¿/¿ rats supplemented with beta-alanine (to increase tissue carnosine content), and a control group. All groups, except the control, will receive doxorubicin treatment. Beta-alanine supplementation will be administered by adding 1.8% of the amino acid to the animals' drinking water starting at 30 days of age, for a total of 16 weeks, with doxorubicin administration during the final six weeks.The evaluated parameters will include in vivo cardiac function assessed by echocardiography, contractility and Ca²¿ transients in isolated cardiomyocytes, mitochondrial respiration, plasma markers of cardiac injury (CK-MB and troponin I), and inflammatory cytokines (IL-1¿, IL-6, and TNF-¿). Additional analyses will examine cardiac tissue morphology using light and transmission electron microscopy, as well as oxidative stress indicators, including protein carbonylation, GSH:GSSG ratio, 8-isoprostane, myeloperoxidase, DNA damage, and ferroptosis markers (total iron content and expression of PTGS2 and CHAC1). Moreover, the expression of proteins involved in the Nrf2 signaling pathway (Nrf2, Keap1, AMPK, and NF-¿B) and pro-inflammatory cytokines in cardiac tissue will be investigated.In addition to the in vivo study, a second project will be conducted to develop and validate a carnosine nanoencapsulation system using the polysaccharide pectin, with the goal of improving its pharmacokinetic profile and enhancing its stability in the bloodstream. The nanoparticles will be produced through molecular self-assembly, and their physicochemical characterization will include measurements of mean particle size, polydispersity index (PDI), and zeta potential (mV) by dynamic light scattering (DLS), as well as morphological analysis by scanning electron microscopy (SEM).Subsequently, the gastrointestinal stability and intestinal release of the nanoparticles will be evaluated using the simulated human digestion system INFOGEST® 2.0. Finally, degradation assays in human serum will be performed to compare the resistance of free versus nanoencapsulated carnosine to carnosinase activity, aiming to confirm the efficacy of the nanoformulation as a strategy to enhance the molecule's systemic protective potential. (AU)