Partnerzy

Streszczenie:
In patients with testicular germ cell tumours (TGCT), sperm cryopreservation prior to anti-cancer treatment represents the main fertility preservation approach. However, it is associated with a low sperm recovery rate after thawing. Since sperm is a high-energy demanding cell, which is supplied by glycolysis and oxidative phosphorylation (OXPHOS), mitochondrial dysfunctionality can directly result in sperm anomalies. In this study, we investigated the bioenergetic pattern of cryopreserved sperm of TGCT patients in comparison with normozoospermic samples using two state-of-the-art methods: the Extracellular Flux Analyzer (XF Analyzer) and two-photon fluorescence lifetime imaging microscopy (2P-FLIM), in order to assess the contributions of OXPHOS and glycolysis to energy provision. A novel protocol for the combined measurement of OXPHOS (oxygen consumption rate: OCR) and glycolysis (extracellular acidification rate: ECAR) using the XF Analyzer was developed together with a unique customized AI-based approach for semiautomated processing of 2P-FLIM images. Our study delivers optimized low-HEPES modified human tubal fluid media (mHTF) for sperm handling during pre-analytical and analytical phases, to maintain sperm physiological parameters and optimal OCR, equivalent to OXPHOS. The negative effect of cryopreservation was signified by the deterioration of both bioenergetic pathways represented by modified OCR and ECAR curves and the derived parameters. This was true for normozoospermic as well as samples from TGCT patients, which showed even stronger damage within the respiratory chain compared to the level of glycolytic activity impairment. The impact of cryopreservation and pathology are supported by 2P-FLIM analysis, showing a significant decrease in bound NADH in contrast to unbound NAD(P)H, which reflects decreased metabolic activity in samples from TGCT patients. Our study provides novel insights into the impact of TGCT on sperm bioenergetics and delivers a verified protocol to be used for the assessment of human sperm metabolic activity, which can be a valuable tool for further research and clinical andrology.

Słowa kluczowe:
TGCT, spermatozoa, sperm biochemistry, sperm function, energetic metabolism, oxidative phosphorylation, XF Analyzer, 2P-FLIM, infertility, cancer

Streszczenie:
Testicular cancer is the most common form of cancer in young men of reproductive age and its incidence is increasing globally. With the currently successful treatment and 95% survival rate, there is a need for deeper understanding of testicular cancer-related infertility. Most patients with testicular cancer experience semen abnormalities prior to cancer therapy. However, the exact mechanism of the effect of testicular cancer on sperm anomalies is not known. Mitochondria are organelles that play a crucial role in both tumorigenesis and spermatogenesis and their malfunction may be an important factor resulting in sperm abnormalities in testicular cancer patients. Within the scope of this review, we will discuss current knowledge of testicular cancer-related alterations in the ATP production pathway, a possible pathophysiological switch from oxidative phosphorylation (OXPHOS) to glycolysis, as well as the role of oxidative stress promoting sperm dysfunction. In this regard, the review provides a summary of the impact of testicular cancer on sperm quality as a possible consequence of impaired mitochondrial function including the energy metabolic pathways that are known to be altered in the sperm of testicular cancer patients.