Gaps and fragmentation of the superficial cortex in the abdominal and pelvic lymph nodes of elderly Japanese

Abstract

Gaps and fragmentation of the superficial lymph node cortex are considered to provide intranodal shunt flow between the afferent and efferent vessels. Using serial sections of 205 nodes obtained from 27 donated cadavers more than 70 years of age, we examined the histological architecture of the abdominal and pelvic nodes in elderly Japanese. Secondary follicles were rare in the specimens. Cortex gaps were, to a greater or lesser degree, found in all nodes. We classified these nodes into three types according to how often the gap occurred. Type 1 nodes, with a relatively complete shield for the afferent lymph, were most frequently found in gastric nodes, whereas type 3 nodes, with numerous gaps, were often observed in the colic, para-aortic and pelvic nodes. The type 3 nodes showed a specific architecture characterized by a fragmented superficial cortex, three-dimensionally assembled cords and a common sinus between them. Primary follicles were located in the assembled cord structures as well as at the superficial cortex. Irrespective of the type, B and T lymphocyte areas were intermingled in the cortex-like areas. The present results reveal region-specific histological heterogeneity in aged human visceral nodes. Due to increased surface areas, the type 3 architecture seemed to accelerate systemic immunity rather than act as a local barrier in the para-aortic and pelvic nodes, which are located centrally along the lymphatic drainage routes. However, thick trabeculae often seemed to develop in the type 3 sinus to decrease nodal function with aging.

Does senescence affect lymph node number and morphology? A systematic review

“…The proportion of the cross‐sectional area of axillary and inguinal lymph nodes occupied by follicular cortex decreased from approximately 10–25% in young adults to about 5% in those >70 years of age; cervical and mesenteric nodes failed to show this decline. In contrast, studies in elderly Japanese cadavers with no history of neoplasia found that superficial lymph nodes from cervical, axillary and inguinal regions generally had better preserved cortical lymphoid tissue than visceral nodes . These authors noted that cortical deficiencies were most apparent in colic, para‐aortic and pelvic lymph nodes.…”

“…There is general agreement that the volume of cortical lymphoid tissue in adult lymph nodes diminishes with senescence . As the cortex shrinks, it may become fragmented into ‘islands’ separated by expanding cortical and medullary sinuses . There is also loss of paracortical tissue, normally populated mainly by T cells, but the interface between B and T lymphocytes tends to be preserved .…”

“…Lymphoid tissue loss in the medullary cords of lymph nodes has been reported with senescence but to a lesser extent than cortical loss . In both humans and animals, medullary cords have been stated to become thinner with advancing age, resulting in widening of medullary sinuses and their extension into the cortex . In addition, fluid‐filled cavities or cystic spaces have been described in the hilar region or medullary zone of lymph nodes from older humans and laboratory animals …”

“…14,18,20,[22][23][24][25][26][27] As the cortex shrinks, it may become fragmented into 'islands' separated by expanding cortical and medullary sinuses. 14,[25][26][27] There is also loss of paracortical tissue, normally populated mainly by T cells, but the interface between B and T lymphocytes tends to be preserved. 17 The extent of cortical lymphoid loss varies between lymph node basins.…”

“…In contrast, studies in elderly Japanese cadavers with no history of neoplasia found that superficial lymph nodes from cervical, axillary and inguinal regions generally had better preserved cortical lymphoid tissue than visceral nodes. 25,27 These authors noted that cortical deficiencies were most apparent in colic, para-aortic and pelvic lymph nodes. Thus, there appear to be basin-specific variations in the loss of cortical lymphoid tissue with advancing age, although it is unclear which basins are most affected.…”