Title Promoter Affiliations Abstract "Impact of heat stress on male fertility: Elucidating testicular pathophysiology and the role of microRNA from sperm and extracellular vesicles on fertility and embryo development." "Ann Van Soom" "Department of Internal Medicine, Reproduction and Population Medicine" "In humans, testicular temperature must be ~3 ºC below body core temperature for production of high-quality, fertile sperm. Increased testicular temperature can be caused by several known pathologies (e.g. varicocele) or behaviours (e.g. hot baths; sitting for several hours). Consequently, leading to low sperm quality and infertility. Furthermore, due to global climate change and intense heat episodes, heat stress is nearly universally a major issue in mammals. Therefore, there is a need to elucidate pathophysiological pathways involved in heat stress impairing testicular function and spermatogenesis in men. The model of choice for this study is the bovine, which include a heat resistant (Bos indicus) and a heat sensitive (Bos taurus) breed. Our hypothesis is that testicular cells respond differently to heat stress and heat resistant animals will present better cell defense mechanisms with lower expression of apoptotic markers. Furthermore, microRNA profile from sperm cells will differ, based on the stage of the cycle when the stress took place. Lastly, paternal heat stress will impact embryo quality, development and gene expression. The data obtained through this proposal will be fundamental to answer important questions regarding how paternal heat stress impacts fertility in men. Furthermore, it will allow the identification of potential heat resistance markers. The results obtained, will support development of treatments for infertility and improving sperm quality." "Backup mandate Research Council: The stalled fertility transition in sub-Saharan Africa: a case study of Congolese women A mixed methods approach of fertility among Congolese women in the Democratic Republic of Congo and Belgium since the 1960s" Sociology "Similar to many sub-Saharan African countries, the Democratic Republic of Congo (DRC) has known high fertility rates for years and seems to demonstrate a slowing or stalling fertility transition due to decades of continuous political instability, insecurity, violence and external exploitation. High fertility combined with decreasing mortality results in rapid population growth, which creates an array of social, economic and environmental challenges. This project addresses the stalled fertility transition in DRC by means of a mixed-methods approach. The overarching aim is to provide an exhaustive picture of fertility and its transition in DRC. Three specific research objectives are tackled: (1) obtaining a complete image of the past and current fertility trends and determinants in DRC; (2) discovering the fertility disparities between women in DRC and Congolese migrants in Belgium; and (3) gaining more insight into the mechanisms, motives and social and cultural aspects underlying fertility behaviour of Congolese women. Not only will the results provide new insights in the stalled fertility transition in DRC and SSA, this research will also contribute to the migrant fertility knowledge in Belgium as it is unknown how the high Congolese fertility rates translate to a Belgian environment." "Fertility preservation in boys treated for cancer: evaluating the impact of harvesting testicular tissue at young age on the later pubertal development and fertility (prospective study)" "Ellen Goossens" "Surgical clinical sciences, Clinical sciences, Basic (bio-) Medical Sciences" "The number of childhood cancer survivors has increased thanks toadvances in cancer treatment. Although for long it was assumed thatchildren were more resistant to cancer treatment, now, there isenough evidence that they are also at risk for lifelong sterility. Sincespermatogenesis only starts at puberty, prepubertal boys cannotbenefit from sperm banking before treatment. Because the progenitorcells (spermatogonial stem cells) are present in the testes since birth,banking of testicular tissue may prevent later sterility in boys exposedto cancer treatment. Our research group has performed pioneeringwork concerning the development of fertility preservation strategiesand translation towards the clinic. Since 2002, the UZ Brussel storedtesticular tissue from >100 boys. Some of these patients have beenfollowed by an oncologist and endocrinologist. A retrospective studydemonstrated that this follow-up was far from standardized withirregular consultations and plenty of missing data. Therefore, strongconclusions on the effect of a testicular biopsy at young age on thelater pubertal development and fertility could not be drawn. However,these data allowed to improve the follow-up protocol.Now, we aim to use this new follow-up protocol in a prospective studyto evaluate the impact of harvesting testicular tissue at young age onthe later pubertal development and on fertility at adult age. This willallow further improvement of fertility preservation strategies." "Fertility preservation in boys treated for cancer: what is the effect of harvesting testicular tissue in childhood on their later pubertal development and fertility?" "Ellen Goossens" "Surgical clinical sciences, Clinical sciences, Basic (bio-) Medical Sciences" "The survival rate of children diagnosed with cancer has improved thanks to more effective radio- and chemotherapy. Although for long it was assumed that children were more resistant to gonadotoxic treatments, now, we know that they are at risk for lifelong sterility too. Since spermatogenesis only starts after puberty, pre-pubertal boys cannot benefit from semen banking before treatment. Because the progenitor cells (spermatogonial stem cells or SSCs) are present in the testis, cryopreservation of testicular tissue may prevent sterility in young boys exposed to gonadotoxic treatments. In the past two decades, the research group biology of the testis (BITE) at the Vrije Universiteit Brussel has performed pioneering work concerning the development of fertility preservation strategies. Since 2002, the university hospital (UZ Brussel) has stored testicular tissue from more than 100 paeditric patients. Some of these patients have been followed up by both an oncologist and an endocrinologist. In this project, we aim to: (1) perform a retrospective study to evaluate the impact of harvesting testicular tissue at childhood on the later pubertal development; (2) standardize the follow-up protocol in collaboration with other European centers offering testicular tissue banking; (3) perform a European-wide prospective study to evaluate the impact of harvesting testicular tissue at childhood on the later pubertal development and fertility status at adult age (>18 years)." "Fertility deficiency in female cystic fibrosis patients: deciphering the role of the endometrium as prime player into pregnancy" "Hugo Vankelecom" "Stem Cell and Developmental Biology" "Manifold female cystic fibrosis (CF) patients suffer from deficient fertility, often facing problems to become pregnant. Underlying reasons remain understudied. In particular, it is largely unknown how dysfunction of the endometrium is involved, the womb’s inner lining and prime player into embryo implantation and development. This gap is mainly due to lack of appropriate research models. Previously, we have developed organoids from healthy and diseased human endometrium that faithfully recapitulate the endometrium’s (patho-)physiology, climaxing in the competence to imitate the menstrual cycle ‘in the dish’ and showing the compelling capacity to model diseased endometrium. Now, we are establishing organoids (as well as derived, advanced assembloids and implantation models) from fertility-deficient CF endometrium to in-depth decipher molecular, cellular and functional aberrations (as compared to healthy, fertile endometrium) that may underly the fertility deficiency. In addition, we will decode the impact of new-era CFTR modulators on the CF endometrium (and thus fertility). Our study will provide deep insights into the role of the endometrium in CF-associated fertility deficiency, and has the potential to reveal new ideas toward therapy restoring reproductive fitness, which can be tested using the biomimetic models. In the end, we aspire to meet the strong desire of CF patients to get increased attention to their reproductive problems and their desire to have children." "Impact of soil fertility on photosynthesis and photosynthate allocation in undisturbed primary rainforests in French Guiana" "Ivan Janssens" "Plant and Ecosystems (PLECO) - Ecology in a time of change" "Tropical forests are among the most diverse ecosystems in the world and account for more than one third of global primary productivity. Tropical rainforests thus play a key role in the global carbon (C) balance. Most tropical forests are phosphorus (P) rather than nitrogen (N) limited, in contrast to the much better studied temperate and boreal forests. The effects of soil fertility on C cycling in tropical rainforests is, however, still poorly understood. The aim of this study is twofold: I want to improve our understanding of photosynthesis of tropical forests and how this changes along gradients of soil N and P availability. Further, I will investigate how plant C allocation varies along these gradients. Ecosystem C allocation is very important because it determines the residence time of C in the ecosystem and thereby the CO2 removal from the atmosphere. Both processes will be studied in the lowland tropical rainforests of French Guiana. The rainforests I will study are virtually undisturbed and cover a large gradient in soil fertility, which will be even enlarged by a fertiliser addition experiment. Therefore, these forests are ideally suited to study effects of nutrient imbalances on the functioning of tropical rainforests." "Impact of soil fertility on photosynthesis and photosynthate allocation in undisturbed primary rainforests in French Guiana." "Ivan Janssens" "Plant and Ecosystems (PLECO) - Ecology in a time of change" "Tropical forests are among the most diverse ecosystems in the world and account for more than one third of global primary productivity. Tropical rainforests thus play a key role in the global carbon (C) balance. Most tropical forests are phosphorus (P) rather than nitrogen (N) limited, in contrast to the much better studied temperate and boreal forests. The effects of soil fertility on C cycling in tropical rainforests is, however, still poorly understood. The aim of this study is twofold: I want to improve our understanding of photosynthesis of tropical forests and how this changes along gradients of soil N and P availability. Further, I will investigate how plant C allocation varies along these gradients. Ecosystem C allocation is very important because it determines the residence time of C in the ecosystem and thereby the CO2 removal from the atmosphere. Both processes will be studied in the lowland tropical rainforests of French Guiana. The rainforests I will study are virtually undisturbed and cover a large gradient in soil fertility, which will be even enlarged by a fertiliser addition experiment. Therefore, these forests are ideally suited to study effects of nutrient imbalances on the functioning of tropical rainforests." "Liberalism's Fertility Problem" "Bouke De Vries" "Department of Philosophy and moral sciences" "Across all Abrahamic religions, it has been found that the more religious people are, the more children they have. However, whereas political demographers such as Eric Kaufman have shown that the growth of religious fundamentalist groups that combine relatively high fertility with relatively high retention rates such as the Haredim, Laestadians, Salafi-Islamists, and Orthodox Calvinists poses (long-term) challenges to liberal democracies, philosophers have not considered what, if anything, states may or should do about this. Are there morally permissible/necessary ways of ensuring that there remain enough liberal-minded people to maintain liberal institutions, assuming, as sociologist Christian Joppke puts it bluntly, that ‘you cannot run a liberal state that is filled up to the ceiling with illiberal people’? This scholarly project is the first to provide an answer to this (understandably) sensitive question." "Restoring fertility by the 3R-approach : rejuvenating, replacing or reconstructing the oocyte" "Katrien Smits, Björn Heindryckx, Dieter Deforce, Luc Peelman, Ann Van Soom" "Department of Human Structure and Repair, Department of Pharmaceutics, Department of Veterinary and Biosciences, Department of Internal Medicine, Reproduction and Population Medicine" "Female infertility is largely caused by increased age, coinciding with increased aneuploidy and inferior cytoplasm. We will identify RNA cargo in extracellular vesicles derived from follicular fluid and stem cells in human and animal models, and check their function during final oocyte maturation. Aneuploidy and cytoplasmic inferiority will be eliminated by generation of oocytes by nuclear transfer and haploidization." "Climate Change and demographic behaviour: differential climate scenarios, fertility desires and intentions" "Jan Van Bavel" "Centre for Sociological Research" "Growing concerns about climate change and the environment, especially among younger people, challenges the sustainability of established habits and consumption patterns. This issue raises questions about its current and potential implications for family planning. Although the existing literature in this field is still limited and findings are mixed, preliminary findings suggest a negative relationship between reproductive intentions and concern about climate change. Recent events, such as the Birth Strikes movement, emphasize how concerns about the planet's future and associated uncertainties are causing some people to reconsider their positive views on parenthood they may have had in earlier times. The primary objective of this research is to comprehensively explore this phenomenon in diverse populations. This study aims to investigate individuals whose short-term and long-term family planning intentions may deviate from their desires, while taking into account factors such as age, gender, education, and current parenthood status, all of which may influence the relationship between environmental concerns and family planning decisions. By investigating intentions regarding fertility and family size, this study could contribute to a more comprehensive understanding of the impact of environmental concern on family planning."