Changes in neuromuscular structure and functions of human colon during ageing are region-dependent

Abstract

In ascending not descending colon, ageing impairs cholinergic function.

Normative values for region‐specific colonic and gastrointestinal transit times in 111 healthy volunteers using the 3D‐Transit electromagnet tracking system: Influence of age, gender, and body mass index

“…They did however, observe significant functional changes in the ascending colon with increasing age such as an increased likelihood of muscle relaxation, rather than contraction when electrically stimulated, an increase in choline acetyltransferase immunoreactive neurons and a decline in cholinergic function. 38 These changes may well manifest as longer transit times that we have observed in the right side of the colon of elderly subjects.…”

“…35 Furthermore, some studies have reported intrinsic age-related changes in the colon such as the neurodegeneration of myenteric nerves, which may explain slower colonic transit in the elderly. 36,37 However, a recent large-scale study by Broad et al 38 showed no changes in the number of myenteric and nitrergic neurons or intramuscular nerve densities in ascending and descending colon tissue samples of elderly subjects. They did however, observe significant functional changes in the ascending colon with increasing age such as an increased likelihood of muscle relaxation, rather than contraction when electrically stimulated, an increase in choline acetyltransferase immunoreactive neurons and a decline in cholinergic function.…”

“…They did however, observe significant functional changes in the ascending colon with increasing age such as an increased likelihood of muscle relaxation, rather than contraction when electrically stimulated, an increase in choline acetyltransferase immunoreactive neurons and a decline in cholinergic function 38. ASC: ascending colon, TRA: transverse colon, DESC: descending colon, RSIG: rectosigmoid emerge with advancing age such as the concomitant use of medications, reduced intake of dietary fiber, and reduced levels of activity or impaired mobility which may have an impact on overall gut and colonic function.…”

Wnt-induced, TRP53-mediated Cell Cycle Arrest of Precursors Underlies Interstitial Cell of Cajal Depletion During Aging

“… 7 However, age-related depletion of enteric neurons is less evident in the stomach, and nitrergic neurons are spared in aging humans, rats, and mice. 8 , 9 , 10 , 11 , 12 , 13 In contrast, interstitial cells of Cajal (ICC), electrical pacemakers, mediators of nitrergic and cholinergic neuromuscular neurotransmission, and regulators of smooth muscle membrane potential and tone, 14 steadily decline at a rate of ∼13% per decade of adult life. 15 In progeric mice hypomorphic for the anti-aging protein Klotho ( klotho mice), 16 we previously reported a profound decrease in gastric ICC accompanying impaired fundal nitrergic inhibitory neuromuscular neurotransmission, which occurred without a reduction in neuronal nitric oxide synthase expression or enteric neuron numbers.…”

The asymmetric innervation of the circular and longitudinal muscle of the mouse colon differently modulates myogenic slow phasic contractions

“…When these pharmacological conditions are not used, electrical stimulation does not discriminate between inhibitory and excitatory motor neurons and therefore, a complex response is recorded involving “on and off” contractions. The interpretation of these results is always difficult since inhibitory responses, rebound repolarizations and excitatory responses overlap . In non‐nitrergic, non‐purinergic conditions, cholinergic excitatory neurons (atropine sensitive) are predominant in both layers.…”