Aging-related severe hypertension induces detrusor underactivity in rats

The Change of Detrusor Contractility at 5 Years After Transurethral Resection of the Prostate: A Single Center Prospective Observational Study

OBJECTIVE

To prospectively assess the impact of transurethral resection of the prostate (TURP) on detrusor function using pressure flow study (PFS) at 5 years after surgery in a single center prospective non-randomized observational study.

METHODS

Sixty consecutive male patients were prospectively enrolled and underwent TURP from November 2014 to November 2018. A questionnaire survey, free uroflowmetry, and PFS were performed at baseline, and 6, 24, and 60 months after surgery. We divided the age groups at 70 years and defined the younger group as those younger than 70 years, and the elderly group as those aged 70 years or older. The primary endpoint was the change in the bladder contractility index (BCI).

RESULTS

Of the 60 patients, 39 completed the protocol. Regardless of age, the bladder outlet obstruction indices at 6, 24, and 60 months after surgery were significantly lower than before surgery (all, P<.01). Although the BCI did not significantly change during 60 months for the entire group of 39 patients, it was significantly decreased at 60 months (85.6) after surgery compared to before surgery (102) in the elderly group (P=.02).

CONCLUSION

We prospectively evaluated detrusor contractility up to 5 years after TURP. It was significantly reduced in the elderly, in spite of which the relief of bladder outlet obstruction was maintained for 5 years after surgery.

A New Rat Model of Sacral Cord Injury Producing a Neurogenic Bladder and Its Functional and Mechanistic Studies

Sacral spinal cord injury (SSCI) can disrupt bladder neuromodulation and impair detrusor function. Current studies provide limited information on the histologic and genetic changes associated with SSCI-related neurogenic lower urinary tract dysfunction (NLUTD), resulting in few treatment options. This study aimed to establish a simple animal model of SSCI to better understand the disease progression. Ninety 8-week-old Sprague-Dawley (SD) rats were randomly separated into sham operation and SSCI groups. The SSCI group underwent sacral spinal cord injury, while the sham group did not. Urodynamic and histological assessments were conducted at various intervals (1, 2, 3, 4, and 6 weeks) post-injury to elucidate the disease process. Urodynamic examinations revealed significant bladder dysfunction in the SSCI group compared to the sham group, stabilizing around 3-4 weeks post-injury. Histological examination, including hematoxylin-eosin and Masson's trichrome staining, correlated these functional changes with bladder microstructural alterations. RNA-seq was performed on bladder tissues from the sham group and SSCI group at 6 weeks to identify differentially expressed genes and pathways. Selected genes were further analyzed using polymerase chain reaction (PCR). The findings indicated a pronounced inflammatory response in the first 2 weeks post-SSCI, progressing to bladder fibrosis at 3-4 weeks. In conclusion, this study presents a reliable, reproducible, and straightforward SSCI model, providing insights into bladder functional and morphological alterations post-SSCI and laying the groundwork for future therapeutic research.

Multi-omic analysis revealed the therapeutic mechanisms of Alpinia oxyphylla fructus water extract against bladder overactivity in spontaneously hypertensive rats

OBJECTIVE

Alpinia oxyphylla fructus without impurities and shells is called "Yi-Zhi-Ren" (YZR) in Chinese, and traditionally used to alleviate enuresis. The aim of this study was to investigate the effects and underlying mechanisms of YZR in the treatment of overactive bladder (OAB) in spontaneously hypertensive rats (SHR), a vascular disorder-related OAB model.

METHODS

A 3-week administration of YZR water extract (p.o.) was done, followed by urodynamics to measure bladder parameters. Changes in bladder structure were observed through H&E staining and Masson's staining. An integrated approach involving network pharmacology, transcriptomics and metabolomics was employed to elucidate the potential mechanisms of YZR, and the key proteins involved in the mechanisms were validated by Western blotting. Additionally, network pharmacology was used to predict the relationship between YZR's active components and validated proteins.

RESULTS

YZR treatment significantly improved the bladder storage parameters, tightened the detrusor layer, reduced inflammatory infiltration, and decreased collagen proportion in the SHR bladder. These results indicated that YZR water extract can alleviate OAB symptoms and improve bladder structure. Integrated analysis suggested that YZR may affect extracellular matrix-receptor interaction and calcium signaling pathway. Western blotting results further confirmed that the reduction in key proteins, such as TGFβ1, p-SMAD3, collagen III, Gq and PLCβ1, involved in collagen synthesis and calcium signaling pathways after YZR treatment. Network pharmacology predicted that sitosterol, chrysin, and nootkatone were potential components responsible for YZR's therapeutic effect on OAB.

CONCLUSION

YZR's mechanisms of action in treating OAB involved the TGFβ1-SMAD3 signaling pathway-related collagen synthesis and Gq-PLCβ1 calcium signaling pathway, which are associated with detrusor contraction frequency and strength, respectively.

Human Omentin-1 Administration Ameliorates Hypertensive Complications without Affecting Hypertension in Spontaneously Hypertensive Rats

Hypertension is one of the major risk factors for cardiovascular diseases and is caused by various abnormalities including the contractility of blood vessels. Spontaneously hypertensive rats (SHR), whose systemic blood pressure increases with aging, are a frequently used animal model for investigating essential hypertension and related complications in humans due to the damage of several organs. Human omentin-1 is an adipocytokine consisting of 313 amino acids. Serum omentin-1 levels decreased in hypertensive patients compared with normotensive controls. Furthermore, omentin-1 knockout mice showed elevated blood pressure and impaired endothelial vasodilation. Taken together, we hypothesized that adipocytokine, human omentin-1 may improve the hypertension and its complications including heart and renal failure in the aged SHR (65-68-weeks-old). SHR were subcutaneously administered with human omentin-1 (18 μg/kg/day, 2 weeks). Human omentin-1 had no effect on body weight, heart rate, and systolic blood pressure in SHR. The measurement of isometric contraction revealed that human omentin-1 had no influence on the enhanced vasocontractile or impaired vasodilator responses in the isolated thoracic aorta from SHR. On the other hand, human omentin-1 tended to improve left ventricular diastolic failure and renal failure in SHR. In summary, human omentin-1 tended to improve hypertensive complications (heart and renal failure), while it had no influence on the severe hypertension in the aged SHR. The further study of human omentin-1 may lead to the development of therapeutic agents for hypertensive complications.

Urinary ATP Levels Are Controlled by Nucleotidases Released from the Urothelium in a Regulated Manner

Adenosine 5′-triphosphate (ATP) is released in the bladder lumen during filling. Urothelial ATP is presumed to regulate bladder excitability. Urinary ATP is suggested as a urinary biomarker of bladder dysfunctions since ATP is increased in the urine of patients with overactive bladder, interstitial cystitis or bladder pain syndrome. Altered urinary ATP might also be associated with voiding dysfunctions linked to disease states associated with metabolic syndrome. Extracellular ATP levels are determined by ATP release and ATP hydrolysis by membrane-bound and soluble nucleotidases (s-NTDs). It is currently unknown whether s-NTDs regulate urinary ATP. Using etheno-ATP substrate and HPLC-FLD detection techniques, we found that s-NTDs are released in the lumen of ex vivo mouse detrusor-free bladders. Capillary immunoelectrophoresis by ProteinSimple Wes determined that intraluminal solutions (ILS) collected at the end of filling contain ENTPD3 > ENPP1 > ENPP3 ≥ ENTPD2 = NT5E = ALPL/TNAP. Activation of adenylyl cyclase with forskolin increased luminal s-NTDs release whereas the AC inhibitor SQ22536 had no effect. In contrast, forskolin reduced and SQ22536 increased s-NTDs release in the lamina propria. Adenosine enhanced s-NTDs release and accelerated ATP hydrolysis in ILS and lamina propria. Therefore, there is a regulated release of s-NTDs in the bladder lumen during filling. Aberrant release or functions of urothelial s-NTDs might cause elevated urinary ATP in conditions with abnormal bladder excitability.

Effects of losartan on bladder dysfunction due to aging-related severe hypertension in rats

Aging is a major risk factor for bladder dysfunction. Anti-hypertensive drugs, angiotensin II type 1 receptor blockers (ARBs), are reported to ameliorate lower urinary tract dysfunction in rodent models and humans. We aimed to examine the preventive effect of an ARB, losartan, against bladder dysfunction due to aging-related severe hypertension. Male spontaneously hypertensive rats (SHRs) (36-week-old) were administered losartan (0, 3, or 10 mg/kg, p.o.) for 18 weeks. Age-matched, vehicle-treated Wistar Kyoto rats (WKYs) were used as controls. After the treatments, bladder and renal weight, mean blood pressure, and voiding parameters were measured. Additionally, detrusor thickness and bladder arterial wall thickness were evaluated using hematoxylin and eosin staining. Renal morphology was also assessed using periodic acid-Schiff staining. Compared to WKYs, SHRs demonstrated significantly higher bladder weight/body weight ratio (BBR), renal weight/body weight ratio, mean blood pressure, detrusor thickness, bladder arterial wall thickness, urine output, water intake, post-voiding residual urine volume, bladder capacity, intercontraction interval, and rate of glomerular and tubular injury and a lower urine osmolality. A low dose of losartan decreased the urine output, post-voiding residual urine volume, and bladder capacity in SHRs but not mean blood pressure in SHRs. A high dose of losartan decreased the BBR, mean blood pressure, detrusor thickness, bladder arterial wall thickness, post-voiding residual urine volume, bladder capacity, intercontraction interval, and glomerular and tubular injury in SHRs. Losartan inhibits bladder dysfunction in aged SHRs. The ARB losartan might be a preventive drug for bladder dysfunction due to aging-related severe hypertension.