Faculty Bibliography

Importance: A neurophysiologic signature of the melanopsin-mediated persistent constriction phase of the pupillary light reflex may represent a surrogate biomarker for the integrity of the retinohypothalamic tract, with potential utility for investigating alterations in homeostatic mechanisms associated with brain disorders and implications for identifying new treatments. Objective: To characterize abnormalities of retinal architecture in patients with multiple sclerosis (MS) and corresponding alterations in the melanopsin-mediated sustained pupillary constriction response. Design, Setting, and Participants: The case-control study was an experimental assessment of various stimulus-induced pupillary response characteristics and was conducted at a university clinical center for MS from September 6, 2012, to February 2015. Twenty-four patients with MS (48 eyes) and 15 individuals serving as controls (30 eyes) participated. The melanopsin-mediated, sustained pupillary constriction phase response following cessation of a blue light stimulus was compared with the photoreceptor-mediated pupillary constriction phase response following cessation of a red light stimulus. Optical coherence tomography was used to characterize the association between pupillary response characteristics and alterations in retinal architecture, specifically, the thickness of the retinal ganglion cell layer and inner plexiform layer (GCL + IPL). Main Outcomes and Measures: Association of pupillary response characteristics with alterations in retinal architecture. Results: Of 24 patients with MS included in the analysis, 17 were women (71%); mean (SD) age was 47 (11) years. Compared with eyes from individuals with MS who had normal optical coherence tomography-derived measures of retinal GCL + IPL thickness, eyes of patients who had GCL + IPL thickness reductions to less than the first percentile exhibited a correspondingly significant attenuation of the melanopsin-mediated sustained pupillary response (mean [SD] pupillary diameter ratios at a point in time, 0.18 [0.1] vs 0.33 [0.09]; P < .001, generalized estimating equation models accounting for age and within-patient intereye correlations). Conclusions and Relevance: In this case-control study, attenuation of the melanopsin-mediated sustained pupillary constriction response was significantly associated with thinning of the GCL + IPL sector of the retina in the eyes of patients with MS, particularly those with a history of acute optic neuritis. Melanopsin-containing ganglion cells in the retina represent, at least in part, the composition of the retinohypothalamic tract. As such, our findings may signify the ability to elucidate a putative surrogate neurophysiologic signature that correlates with a constellation of homeostatic mechanisms in both health and illness.

Purpose The association between exposure to testosterone replacement therapy (TRT) and prostate cancer risk is controversial. The objective was to examine this association through nationwide, population-based registry data. Methods We performed a nested case-control study in the National Prostate Cancer Register of Sweden, which includes all 38,570 prostate cancer cases diagnosed from 2009 to 2012, and 192,838 age-matched men free of prostate cancer. Multivariable conditional logistic regression was used to examine associations between TRT and risk of prostate cancer (overall, favorable, and aggressive). Results Two hundred eighty-four patients with prostate cancer (1%) and 1,378 control cases (1%) filled prescriptions for TRT. In multivariable analysis, no association was found between TRT and overall prostate cancer risk (odds ratio [OR], 1.03; 95% CI, 0.90 to 1.17). However, patients who received TRT had more favorable-risk prostate cancer (OR, 1.35; 95% CI, 1.16 to 1.56) and a lower risk of aggressive prostate cancer (OR, 0.50; 95% CI, 0.37 to 0.67). The increase in favorable-risk prostate cancer was already observed within the first year of TRT (OR, 1.61; 95% CI, 1.10 to 2.34), whereas the lower risk of aggressive disease was observed after > 1 year of TRT (OR, 0.44; 95% CI, 0.32 to 0.61). After adjusting for previous biopsy findings as an indicator of diagnostic activity, TRT remained significantly associated with more favorable-risk prostate cancer and lower risk of aggressive prostate cancer. Conclusion The early increase in favorable-risk prostate cancer among patients who received TRT suggests a detection bias, whereas the decrease in risk of aggressive prostate cancer is a novel finding that warrants further investigation.