Detrusor glycogen reflects the functional history of bladders with partial outlet obstruction

Abstract

OBJECTIVE To assess the relationship between glycogen content in bladder detrusor tissue and historical bladder function in a guinea‐pig model of partial bladder outlet obstruction (PBOO). MATERIALS AND METHODS In male immature guinea pigs PBOO was created with a silver ring around the proximal urethra; a control group had a sham operation for comparison. Longitudinal individual urodynamic data were obtained weekly, so that guinea pigs were killed at different levels of bladder dysfunction. Bladder sections were stained with periodic acid‐Schiff (PAS) to assess overall morphology and glycogen granule density, scored from 0 (no glycogen) to 3. Glycogen scores were related to both the end‐stage and historical extremes of bladder function values. RESULTS Glycogen granules were seen only in the detrusor; as their number increased their location expanded from only close to the serosa (glycogen score 1), through the detrusor (score 2) up to the urothelium (score 3). A glycogen score of 0 correlated with normal values for all urodynamic variables. Compared with a glycogen score of 0 a score of 1 correlated with significant (P < 0.05) changes in end‐stage compliance (decrease) and contractility (increase) and significantly higher historical values for contractility, pressure and number of unstable contractions (NUC). In the group with a glycogen score of 2 there were significant changes in both the end‐stage values and historical extremes for compliance, pressure, contractility and NUC (all P < 0.05). In the group with a glycogen score of 3 all these changes were even more dramatic, except for the end‐stage contractility, for which the increase was not significant. From glycogen score 0 to score 3 all changes increased in magnitude. CONCLUSION A high glycogen content reflects a history of abnormal urodynamic function. This finding exemplifies the added value of structural analysis to urodynamic studies. Further studies are needed to relate bladder structure to the potential for functional recovery.

The detrusor glycogen content of a de‐obstructed bladder reflects the functional history of that bladder during PBOO

“…Whether the glycogen deposition will reduce after longer periods of recovery cannot be concluded. There appears to be a slow trend for reduction as the glycogen scores in animals who were allowed a recovery period after obstruction tended to be lower than the glycogen scores that we previously reported 14 for animals who had the same duration of obstruction but without a recovery period. A few animals that expressed mild urodynamic changes after a short period of PBOO regained normal bladder function rapidly and needed no further monitoring.…”

“…This correlation was also found in our study of glycogen score after PBOO alone. 14 We also tested for each glycogen score group (except glycogen 0) if end-stage urodynamic variables were significantly changed from these variables at the time of deobstruction. In the glycogen score 1 group only the compliance showed a significant difference between the end-stage value and the value at the time of de-obstruction (P < 0.05), becoming normal again.…”

“…We previously examined the intensity of glycogen deposition in the tissue from guinea pigs that had surgically induced PBOO for various periods of time. 14 We found that an increase in glycogen deposits correlated with an increase in bladder abnormality: decreasing compliance and increasing bladder contractility, pressure at maximum flow and the number of unstable contractions. This was true for the situation at the time of tissue collection.…”

Potential for recovery in bladder function after removing a urethral obstruction

“…43 -48 Adaptation to anaerobic conditions is also driving the intrinsic changes in muscle cells mentioned earlier Neurourology and Urodynamics DOI 10.1002/nau We have shown muscle cells from an obstructed bladder build-up of glycogen stores and that the extent of this build-up is related to severity of functional loss during obstruction. 45,46 Such stores may enable anaerobic muscle function and prevent ischemic damage. 44,47,48 Measurements in live animals support the idea that a high bladder pressure can reduce the blood flow in the bladder wall.…”

Etiopathogenesis and management of bladder dysfunction in patients with posterior urethral valves

“…[14] The degree of glycogen deposition in a bladder after the removal of obstruction correlated directly with bladder function during obstruction. The highest glycogen deposition was found in bladders that experienced the highest pressures, most instabilities, lowest compliance, and highest contractility.…”