Ghrelin promotes thymopoiesis during aging
J. Clin. Invest. Vishwa Deep Dixit, et al. 117:2778 doi:10.1172/JCI30248 [Go to this article.]

Figure 2
Ghrelin expression declines with age in thymus. (A) Real-time PCR analysis of mice (n = 5–6) at various ages revealed an age-dependent reduction in ghrelin and GHS-R mRNA expression. Threshold cycle values from individual animals (n = 6) in each group were collapsed and normalized with GAPDH and expressed as average fold change in comparison with 2-month-old mice. (B) The GHS-R expression revealed by FAM-ghrelin binding displayed primarily medullary GHS-R expression, which appears to decrease with age. Medullary regions are outlined with white lines. (C) The total ghrelin protein expression was studied in thymus of 2, 4, 12, 18, and 24-month-old mice. Each section is representative of 4–5 thymi in each group. High ghrelin immunopositivity (brown staining) was observed in cortex as well as medulla of 2- to 4-month-old mice and declined in aging thymus. Original magnification, ×10 (left); ×40 (right). (D) Acylated ghrelin protein expression (arrowheads) also declines with age. Note the significant increase in large lipid vacuoles of adipocytes (A) in the septa (S) of thymus of 12-month-old mice. In contrast to 12-month-old mice, ghrelin expression was expressed in thymic cortex and the medulla in 4-month-old mice. Original magnification, ×10 (B and D).