Changing Blood Factors in Aging
Cell signaling is carried far and wide in the body via the bloodstream. The molecules involve change significantly with age, including a rise in inflammatory signaling and consequent chronic inflammation. This is a reaction to, or consequence of, forms of damage involved in aging, but it is also a source of significant further dysfunction. That much is demonstrated by plasma dilution studies, in which improved tissue function in several organs is noted as a result of diluting the signals carried by the bloodstream in an aged body.
Traditional indicators of biological age are not always informative and often require extensive and expensive analysis. The study of blood factors is a simple and easily accessible way to assess individual health and supplement the traditional indicators of a person's biological age with new objective criteria. With age, the processes of growth and development, tissue regeneration and repair decline; they are gradually replaced by enhanced catabolism, inflammatory cell activity, and insulin resistance. The number of senescent cells supporting the inflammatory loop rises; cellular clearance by autophagy and mitophagy slows down, resulting in mitochondrial and cellular damage and dysfunction. Monitoring of circulated blood factors not only reflects these processes, but also allows suggesting medical intervention to prevent or decelerate the development of age-related diseases.
Blocking factors that negatively affect lifespan is a reasonable strategy to prevent early disability and prolong the active life of older people. Among such strategies, tested in the clinical practice or which will be translated to the clinical practice, one can highlight overcoming the insulin resistance by diet restriction, increasing FGF21 in blood circulation, pharmacological treatment of insulin resistance (e.g., with dehydroepiandrosterone and metformin), stimulation of tissue repair by GH, oxytocin, GDF11, and TIMP2, vascular regeneration with bFGF, EGF, VEGF, PDGF-AB, and BMP9, preventing the development of "inflammaging" by administering anti-inflammatory molecules, including COX-2 inhibitors, leukotriene receptor antagonists, TIMP2, or other matrix metalloproteinase inhibitors, overcoming the cell senescence by administration of TM5441 analogs, optimizing the autophagy and mitophagy with mTOR inhibitors, with TGF-β inhibitors, antioxidant therapy, reduction of NAD+ exhaustion. The indicators and mechanisms discussed above reflect the natural and pathological aging processes.