The potential impacts of circadian rhythm disturbances on male fertility

Abstract

A circadian rhythm is an internalized timing system that synchronizes the cellular, behavioral, and physiological processes of organisms to the Earth’s rotation. Because all physiological activities occur at a specific time, circadian rhythm disturbances can lead to various pathological disorders and diseases. Growing evidence has shown that the circadian clock is tightly connected to male fertility, and circadian perturbations contribute to infertility. The night shiftwork, insufficient sleep, and poor sleep quality are common causes of circadian disturbances, and many studies have reported that they impair sperm quality and increase the risk of male infertility. However, research on the impacts of light, body temperature, and circadian/circannual rhythms is relatively lacking, although some correlations have been demonstrated. Moreover, as the index of sperm quality was diverse and study designs were non-uniform, the conclusions were temporarily inconsistent and underlying mechanisms remain unclear. A better understanding of whether and how circadian disturbances regulate male fertility will be meaningful, as more scientific work schedules and rational lifestyles might help improve infertility.

The transcription factor VAX1 in VIP neurons of the suprachiasmatic nucleus impacts circadian rhythm generation, depressive-like behavior, and the reproductive axis in a sex-specific manner in mice

“…These hormones are required for reproductive health through the production of testosterone and spermiogenesis in males and ovulation, embryo implantation, and follicular health in females ( 89 – 91 ). Though more frequently studied in females, current studies suggest that severe circadian disruption, through changes either in light exposure or via direct disruption to the SCN, may have a mild influence on male fertility ( 92 ). Interestingly, we found that Vax1 Vip males had delayed pubertal onset.…”

Spermatogenesis recovery treatment in less than four months from zero to almost 16 million sperms per milliliter after several cycles of steroids in 44‐year‐old healthy man

“…Active training time and calories burned per day have been both increased by 50%, while sleeping pattern was increased by 20%. Unfortunately, there are not enough clinical studies and evidence that any of these parameters have positive influence on sperm quality 5,19,20 …”

“…He is in the age of 44, which could be already critical for quality of sperm according to Jimbo et al 10 However, taking under consideration all medical exams done, as well as body shape and physical activities (Figure 1), patient had very healthy lifestyle and was in a good condition. In addition to medication, patient worked on addictive habits (smoking, drinking, drugs and medication use, alcohol), 4 sleep pattern, 5 daily sport activities, 19,20 stress level, 3 coffee consumption, 3 food quality, 6 and antioxidants use. 17,18,21,22 Since patient does not smoke or use drugs, only two habits that he changed in this period are reducing alcohol consumption 4-5 drinks per week to 1-2 maximum.…”

“…Unfortunately, there are not enough clinical studies and evidence that any of these parameters have positive influence on sperm quality. 5,19,20 Stress and caffeine consumption was also investigated in the past; 3 however as single or dual factors, there is no prove about direct influence on spermatogenesis. Patient is a manager in big global company at very stressful position, and he made decision that during this period of recovery he would take 5 weeks' vacation in the south of hemisphere (summertime in December and January), to be able to have more outdoor activities, fresh area, access to the beach and more relaxed daily time.…”

Circadian disturbance induces erectile dysfunction by impairing endothelial function

“… 4 5 6 7 This is called circadian rhythm 4 5 6 7 which is essential to maintain physiological functions and guarantee optimal performance for organisms. 6 7 At molecular level for circadian system, 8 9 the circadian locomotor output cycles kaput (CLOCK) and brain/muscle aryl-hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) polymerize the positive complex to activate transcription of other clock genes (such as period 1/2/3 [ PER1/2/3 ], cryptochrome 1/2 [ CRY1/2 ], retinoic acid-related orphan nuclear receptor [ REV-ERB ], and retinoic acid-related orphan receptor [ ROR ]) and clock-controlled genes. 10 11 PER and CRY accumulate in the cytoplasm and translocate to the nucleus to restrict the activity of CLOCK/BMAL1, forming the main negative feedback loop.…”