Influence of age and bladder dysfunction on the contractile properties of isolated human detrusor smooth muscle

Abstract

What’s known on the subject? and What does the study add? The question to be addressed was whether bladder overactivity or obstruction in patients was associated with any changes to the contractile properties of the detrusor smooth muscle, and in addition were there age‐related and gender‐dependent differences in these? The study showed that neither age nor gender per se affected the contractile properties of the smooth muscle from the stable bladder. However, in the pathology groups there was an age‐dependent reduction of nerve‐dependent contractile function, and thus in the overactive bladder there is an age‐dependent functional deneravation. OBJECTIVE • To test the hypothesis that the in vitro contractile properties of human detrusor smooth muscle are dependent on the age, gender and lower urinary tract pathology of the patient. MATERIALS AND METHODS • Contractions were elicited in isolated human detrusor smooth muscle preparations by nerve‐mediated electrical field stimulation, agonist application (carbachol, α,β‐methylene ATP and high‐K solutions) or direct muscle electrical stimulation. • Biopsies (n= 227) were obtained from four groups of patients with: stable bladders (control), bladder outlet obstruction (BOO), idiopathic (IDO), or neurogenic (NDO) detrusor overactivity. RESULTS • The magnitude of nerve‐mediated contractions declined as a function of patients’ age in each of the BOO, IDO and NDO groups but not in the control group. • Contractions elicited by direct muscle activation (10 µm carbachol or electrical stimulation with 20 ms pulses in the presence of 1 µm tetrodotoxin) did not vary with patient age. • Carbachol contractions were significantly smaller in samples from NDO bladders. • Atropine resistance was more prevalent in the pathology groups compared with the control group and was greatest in the IDO group. There was no influence of age in the prevalence or magnitude of atropine‐resistant contractions in any group. • Muscle excitability to direct electrical stimulation was similar in all groups. CONCLUSIONS • In the human bladder there is no evidence for a decline of detrusor smooth muscle contractility or excitability as a function of age, nor any gender difference or presence of pathology. • In the pathology groups there was evidence for a decline of functional innervation with age.

Long-Term Caloric Restriction in Rats may Prevent Age Related Impairment of In Vitro Bladder Function

“…This is supported by findings in isolated strips of human bladder, which demonstrated no decreased detrusor contractility with aging. 19 In contrast, contractile responses to muscarinic stimulation and EFS were impaired in the old plus AL group compared to the young group, which is consistent with a previous report in rats. 7 Contractile responses to EFS after atropine and mATP pretreatment suggest that this was mainly due to impairment of the cholinergic component.…”

Functional properties and connective tissue content of pediatric human detrusor muscle

“…Therefore, different in vitro function between human detrusor tissues from adult and pediatric bladders cannot be explained by a variation of detrusor contractile activation per se. Similar agonist contractile responses have also been measured when fetal and adult animal detrusor tissues were compared and when human detrusor responses from elderly (Ͼ70 yr) or younger patients with either normal or overactive bladders were compared (9,33). Thus, DSM function itself is similarly developed in pediatric and adult bladders and remains so even when aging bladder pathologies emerge.…”

“…However, to our knowledge, there is no study of the density of nerve fibers to DSM during postnatal development. However, in adult human overactive or obstructed bladders, reduced functional innervation, i.e., reduction of T max , is mirrored by reduced nerve density (6,9,11,22), and so a similar association may be hypothesized in postnatal development.…”

“…Atropine resistance of nerve-mediated contractions and functional denervation characterize pathological bladders; there is no evidence of diminished DSM function (9). As functional studies using tissue from neonatal or pediatric patients are lacking, it is unclear if the adult phenotype is present at birth.…”

Does Temporary Catheter Drainage of Urine Improves Detrusor Function in Chronic Urinary Retention in Patients with Bladder Outlet Obstruction.

“…However, a substantial number of these patients have disappointing results and coupled with reluctance to avoid surgery. These patients eventually present as CUR at a later stage thus a advanced age group presentation with CUR is observed [13,[16][17][18][19][20][21][22][23][24][25][26][27]. …”