Ricardo Villares, Dimitri Kakabadse, Yasmina Juarranz, Rosa P. Gomariz, Carlos Martínez-A, and Mario Mellado
PNAS November 26, 2013 110 (48) E4619-E4627; https://doi.org/10.1073/pnas.1314985110
Evidence supports a relationship between the neuroendocrine and the immune systems. Data from mice that overexpress or are deficient in growth hormone (GH) indicate that GH stimulates T and B-cell proliferation and Ig synthesis, and enhances maturation of myeloid progenitor cells.
The effect of GH on autoimmune pathologies has nonetheless been little studied. Using a murine model of type 1 diabetes, a T-cell–mediated autoimmune disease characterized by immune cell infiltration of pancreatic islets and destruction of insulin-producing β-cells, we observed that sustained GH expression reduced prodromal disease symptoms and eliminated progression to overt diabetes.
The effect involves several GH-mediated mechanisms; GH altered the cytokine environment, triggered anti-inflammatory macrophage (M2) polarization, maintained activity of the suppressor T-cell population, and limited Th17 cell plasticity. In addition, GH reduced apoptosis and/or increased the proliferative rate of β-cells.
These results support a role for GH in immune response regulation and identify a unique target for therapeutic intervention in type 1 diabetes.