RESUMO
The growing increases in the global life expectancy and the incidence of chronic diseases as a direct consequence have highlighted a demand to develop effective strategies for promoting the health of the aging population. Understanding conserved mechanisms of aging across species is believed helpful for the development of approaches to delay the progression of aging and the onset of age-related diseases. Mitochondrial hormesis (or mitohormesis), which can be defined as an evolutionary-based adaptive response to low-level stress, is emerging as a promising paradigm in the field of anti-aging. Depending on the severity of the perceived stress, there are varying levels of hormetic response existing in the mitochondria called mitochondrial stress response. Hydrogen sulfide (H2S) is a volatile, flammable, and toxic gas, with a characteristic odor of rotten eggs. However, H2S is now recognized an important gaseous signaling molecule to both physiology and pathophysiology in biological systems. Recent studies that elucidate the importance of H2S as a therapeutic molecule has suggested its protective effects beyond the traditional understanding of its antioxidant properties. H2S can also be crucial for the activation of mitochondrial stress response, postulating a potential mechanism for combating aging and age-related diseases. Therefore, this review focuses on highlighting the involvement of H2S and its sulfur-containing derivatives in the induction of mitochondrial stress response, suggesting a novel possibility of mitohormesis through which this gaseous signaling molecule may promote the healthspan and lifespan of an organism.
RESUMO
BACKGROUND: The articular cartilage is unique in that it contains only a single type of cell and shows poor ability for spontaneous healing. Cartilage tissue engineering which uses mesenchymal stem cells (MSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs) is considered an attractive treatment for cartilage lesions and osteoarthritis. The establishment of cartilage regenerative medicine is an important clinical issue, but the search for cell sources able to restore cartilage integrity proves to be challenging. The aim of this study was to create cartilage grafts from the combination of AT-MSCs and collagen substrates. METHODS: Mesenchymal stem cells were obtained from human donors' adipose tissue, and collagen scaffold, obtained from human skin and cleaned from blood vessels, adipose tissues, and debris, which only preserve dermis and epidermis, were seeded and cultured on collagen substrates and differentiated to chondrocytes. The obtained chondrocyte extracellular matrix of cartilage was then evaluated for the expression of chondrocyte-/cartilage-specific markers, the Cartilage Oligomeric Matrix Protein (COMP), collagen X, alpha-1 polypeptide (COL10A1), and the Collagen II, Human Tagged ORF Clone (COL2A1) by using the reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Our findings have shown that the dermal collagen may exert important effects on the quality of in vitro expanded chondrocytes, leading in this way that the influence of collagen skin matrix helps to produce highly active and functional chondrocytes for long-term cartilage tissue regeneration. CONCLUSION: This research opens up the possibility of generating cartilage grafts with the precise purpose of improving the existing limitation in current clinical procedures.