Paediatric and Neonatal Surgery, Klinikum Stuttgart, Stuttgart, Baden-Württemberg, Germany.
Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, 686 Bay Street, Toronto, ON, M5G0A4, Canada.
Sci Rep. 2021 Aug 27;11(1):17307. doi: 10.1038/s41598-021-96155-4.
Partial bladder outlet obstruction due to prostate hyperplasia or posterior urethral valves, is a widespread cause of urinary dysfunction, patient discomfort and also responsible for immense health care costs. Even after removal or relief of obstruction, the functional and pathologic aspects of obstruction remain as a chronic obstructive bladder disease (COBD). Epigenetic changes, such as DNA methylation, contribute to the persistent character of many chronic diseases, and may be altered in COBD. We tested whether candidate genes and pathways and the pathophysiology of COBD were affected by a hypomethylating agent, decitabine (DAC). COBD was created in female Sprague-Dawley rats by surgical ligation of the urethra for 6 weeks, followed by removal of the suture. Sham ligations were performed by passing the suture behind the urethra. After removal of the obstruction or sham removal, animals were randomized to DAC treatment (1 mg/kg/3-times/week intraperitoneally) or vehicle (normal saline). Bladder function was non-invasively tested using metabolic cages, both one day prior to de-obstruction at 6 weeks and prior to sacrifice at 10 weeks. Residual volume and bladder mass were measured for each bladder. Bladders were examined by immunostaining as well as qPCR. The effects of DNA methyltransferase (DNMT)-3A knockout or overexpression on smooth muscle cell (SMC) function and phenotype were also examined in bladder SMC and ex vivo culture. Residual volumes of the DAC treated group were not significantly different from the NS group. Compared to COBD NS, COBD DAC treatment helped preserve micturition volume with a significant recovery of the voiding efficiency (ratio of the maximum voided volume/maximum bladder capacity) by one third (Fig. 1, p > 0.05). Brain-derived neurotrophic factor (BDNF) variants 1 and 5 were upregulated by COBD and significantly reduced by DAC treatment. Deposition of collagen in the COBD bladder was reduced by DAC, but gross hypertrophy remained. In bladder SMC, DNMT3A overexpression led to a loss of contractile function and phenotype. In bladders, persistently altered by COBD, inhibition of DNA-methylation enhances functional recovery, unlike treatment during partial obstruction, which exacerbates obstructive pathology. The underlying mechanisms may relate to the gene expression changes in BDNF and their effects on signaling in the bladder.
由于前列腺增生或后尿道瓣膜引起的部分膀胱出口梗阻是导致尿功能障碍、患者不适的常见原因，同时也造成了巨大的医疗保健费用。即使梗阻得到解除或缓解，梗阻的功能和病理方面仍然是一种慢性阻塞性膀胱疾病（COBD）。表观遗传改变，如 DNA 甲基化，有助于许多慢性疾病的持续特征，并且可能在 COBD 中发生改变。我们测试了候选基因和途径以及 COBD 的病理生理学是否受到低甲基化剂地西他滨（DAC）的影响。通过对尿道进行 6 周的手术结扎来在雌性 Sprague-Dawley 大鼠中创建 COBD，然后去除缝线。假结扎通过将缝线穿过尿道后面进行。在去除梗阻或假去除后，动物被随机分配到 DAC 治疗（1mg/kg/3 次/周腹腔内）或载体（生理盐水）组。使用代谢笼对膀胱功能进行非侵入性测试，在 6 周时去除梗阻前一天和 10 周时牺牲前进行。测量每个膀胱的残余体积和膀胱质量。通过免疫染色以及 qPCR 检查膀胱。还在膀胱平滑肌细胞（SMC）和体外培养中检查了 DNA 甲基转移酶（DNMT）-3A 敲除或过表达对 SMC 功能和表型的影响。DAC 治疗组的残余体积与 NS 组没有显著差异。与 COBD NS 相比，COBD DAC 治疗有助于保留排尿量，排尿效率（最大排空量/最大膀胱容量的比值）显著恢复三分之一（图 1，p>0.05）。脑源性神经营养因子（BDNF）变体 1 和 5 被 COBD 上调，并被 DAC 治疗显著降低。DAC 减少了 COBD 膀胱中的胶原沉积，但大体肥大仍然存在。在膀胱 SMC 中，DNMT3A 过表达导致收缩功能和表型丧失。在持续受 COBD 改变的膀胱中，抑制 DNA 甲基化增强了功能恢复，而在部分梗阻期间的治疗则会加剧梗阻性病理。潜在的机制可能与 BDNF 的基因表达变化及其对膀胱信号转导的影响有关。
