Table 1.

Treatment options that can prevent thymic atrophy or stimulate thymus

Molecule/therapy option	Treatment	Effects
Zinc	Oral supplement	Lowers age-associated thymic atrophy with partial recovery of lymphocyte functions, as measured by mitogen responsiveness and NK cell activity on mice, and serves as a co-factor of thymulin which is associated with both intrathymic and extrathymic T cell differentiation
Antioxidants	Vitamin E, high-dose vitamin C and N-acetyl cysteine	Reduces thymic atrophy
IL-7	Recombinant human IL-7	Increased TCR diversity in clinical studies in humans, in vitro proliferation of peripheral T cells and increased thymic output in aged mice
Glucocorticoids	Inhibition of glucocorticoids	Glucocorticoids reduce thymic cell count during Salmonella typhimurium and Francisella tularensis infections in mice; therapies with thymopoeitic potential are known to reduce GCs.
Leptin		It reduces thymic atrophy, increases intrathymic IL-7, and decreases pro-inflammatory cytokine release in mice, but not all conditions are suitable for administration.
Keratinocyte growth factor		Increases thymic output and naive T cell pool in aged mice.
Ghrelin, an appetite-stimulant hormone		Improvement in thymocyte numbers, thymic output, and T cell activation in aged mice