ALBERT

Beschreibung: The lower urinary tract (LUT) and micturition reflexes are sexually dimorphic across mammals. Sex as a biological variable is also of critical importance for the development and translation of new medical treatments and therapeutics interventions affecting pelvic organs, including the LUT. However, studies of LUT function with comparisons between the sexes have remained sparse, especially for larger mammals. Detrusor function was investigated by filling cystometry and pressure flow studies in 16 male and 22 female rhesus macaques. By filling cystometry, male subjects exhibited a significantly larger bladder capacity and compliance compared to females. Pressure flow studies showed a significantly higher bladder pressure at voiding onset, peak pressure, and elevation in detrusor-activated bladder pressure from the end of bladder filling to peak pressure in the male subjects. The activation of reflex micturition, with associated detrusor contractions, resulted in voiding in a significantly larger proportion of female compared to male subjects. A higher urethral outlet resistance is suggested in the male subjects. We conclude that sexual dimorphism of detrusor function is prominent in rhesus macaques, shares many features with the human, and merits consideration in translational and pre-clinical research studies of micturition and LUT function in non-human primates.

Beschreibung: Segmentation of axons in light and electron micrographs allows for quantitative high-resolution analysis of nervous tissues, but varied axonal dispersion angles result in over-estimates of fiber sizes. To overcome this technical challenge, we developed a novel shape-adjusted ellipse (SAE) determination of axonal size and myelination as an all-inclusive and non-biased tool to correct for oblique nerve fiber presentations. Our new resource was validated by light and electron microscopy against traditional methods of determining nerve fiber size and myelination in rhesus macaques as a model system. We performed detailed segmental mapping and characterized the morphological signatures of autonomic and motor fibers in primate lumbosacral ventral roots (VRs). An en bloc inter-subject variability for the preganglionic parasympathetic fibers within the L7-S2 VRs was determined. The SAE approach allows for morphological ground truth data collection and assignment of individual axons to functional phenotypes with direct implications for fiber mapping and neuromodulation studies.