Diabetic Cystopathy: Relationship to Autonomic Neuropathy Detected by Sympathetic Skin Response

Time-Dependent Changes of Urethral Function in Diabetes Mellitus: A Review

This article reviewed the current knowledge on time-course manifestation of diabetic urethral dysfunction (DUD), and explored an early intervention target to prevent the contribution of DUD to the progression of diabetes-induced impairment of the lower urinary tract (LUT). In the literature search through PubMed, key words used included “diabetes mellitus,” “diabetic urethral dysfunction,” and “diabetic urethropathy.” Polyuria and hyperglycemia induced by diabetes mellitus (DM) can cause the time-dependent changes in functional and morphological manifestations of DUD. In the early stage, it promotes urethral dysfunction characterized by increased urethral pressure during micturition. However, the detrusor muscle of the bladder tries to compensate for inducing complete voiding by increasing the duration and amplitude of bladder contractions. As the disease progresses, it can induce an impairment of coordinated micturition due to dyssynergic activity of external urethra sphincter, leading to detrusor-sphincter dyssynergia. The impairment of relaxation mechanisms of urethral smooth muscles (USMs) may additionally be attributable to decreased responsiveness to nitric oxide, as well as increased USM responsiveness to α₁-adrenergic receptor stimulation. In the late stage, diabetic neuropathy may play an important role in inducing LUT dysfunction, showing that the decompensation of the bladder and urethra, which can cause the decrease of voiding efficiency and the reduced thickness of the urothelium and the atrophy of striated muscle bundles, possibly leading to the vicious cycle of the LUT dysfunction. Further studies to increase our understandings of the functional and molecular mechanisms of DUD are warranted to explore potential targets for therapeutic intervention of DM-induced LUT dysfunction.

Ability of alpha-lipoic acid to reverse the diabetic cystopathy in a rat model

AIM

The present study was conducted to investigate whether alpha-lipoic acid (alpha-LA) is able to reverse impaired bladder function induced by diabetes in a rat model and to explore the possible mechanism mediating the effect.

METHODS

Male Sprague-Dawley rats were divided randomly into 3 age-matched groups: control, diabetes mellitus (DM) treated with vehicle, and DM with alpha-LA treatment. The diabetic rats were induced by a single intraperitoneal (ip) injection of streptozotocin (60 mg/kg). Six weeks after the induction of DM, the two groups received another 6 weeks of treatment with vehicle or alpha-LA (100 mg/kg, i.p.). Body weight and blood glucose levels were measured weekly. The bladder function was evaluated by in vitro cystometry. The oxidative stress status was determined by biochemical methods, and the level of nerve growth factor was investigated by enzyme-linked immunosorbent assay.

RESULTS

The streptozotocin-induced diabetic rats showed impaired bladder function characterized by increased bladder capacity, decreased bladder contractility (voiding efficiency), and an increase in residual urine. Treatment with alpha-LA significantly normalized the increased bladder capacity for inducing voiding, single-voided volume, and post-void residual volume. Alpha-LA treatment significantly reversed the increased level of malondialdehyde and reduced the activities of both superoxide dismutase and catalase. DM caused a decrease in the bladder nerve growth factor (NGF) level, and alpha-LA upregulated the level of NGF in the diabetic rat bladder.

CONCLUSION

These results indicate that alpha-LA has a beneficial effect on diabetes-induced cystopathy by ameliorating oxidative stress and normalizing the NGF level in the bladder.

Improvement of polyuria, bladder sensation and bladder capacity following renal transplantation

Here, we report a patient with renal failure and bladder dysfunction whose symptoms improved following renal transplantation. A 23-year-old woman underwent renal transplantation for renal failure as a result of dysplastic kidneys. Urodynamic evaluation prior to transplantation showed decreased bladder sensation and increased bladder capacity, probably because of congenital polyuria. One week after surgery, dry mouth disappeared, and urine volume normalized gradually. Urodynamic studies performed 3 and 10 months after transplantation showed improvement of bladder function, and the frequency/volume charts of urination also showed normalization of urine volume. Renal and bladder functions were almost normal 45 months after transplantation. Bladder dysfunction involves numerous factors, but the primary cause was probably congenital polyuria in the present case. This case suggested that blood purification and correction of urine volume by renal transplantation might lead to restoration of normal bladder function.