Aging and lymphatic contractility: Current status

Abstract

Aging impairs lymph flow, which is crucial for fluid and macromolecule homeostasis, fat absorption, and immunity. Aging of the lymphatic system is grossly understudied and may be contributory to many of the aging-related diseases of the elderly. We evaluated aging-associated changes in adult (9 months) and aged (24 months) isolated rat thoracic ducts (TDs) and mesenteric lymphatic vessels (MLV) and demonstrated that there was decreased amplitude, frequency, tone and pumping in aged TDs and MLVs as compared to their adult counterparts. Differences in contractile behavior of aged isolated MLV and those observed in situ suggest an important regulatory involvement of some cellular elements in the immediate environment of aged MLV. We identified mast cells lining MLV and demonstrated a greater degree of basal activation of mast cells in aged mesentery. We also identified increased superoxide and peroxynitrite radicals and other signs of oxidative stress in aged MLV as compared to adult. These studies provided first ground for understanding of some of the mechanisms responsible for impairment of lymphatic function associated with aging.