Cancer treatment in childhood and testicular function : the importance of the somatic environment

Testicular function and future fertility may be affected by cancer treatment during childhood. Whilst survival of the germ (stem) cells is critical for ensuring the potential for fertility in these patients, the somatic cell populations also play a crucial role in providing a suitable environment to support germ cell maintenance and subsequent development. Regulation of the spermatogonial germ-stem cell niche involves many signalling pathways with hormonal influence from the hypothalamo-pituitary-gonadal axis. In this review, we describe the somatic cell populations that comprise the testicular germ-stem cell niche in humans and how they may be affected by cancer treatment during childhood. We also discuss the experimental models that may be utilized to manipulate the somatic environment and report the results of studies that investigate the potential role of somatic cells in the protection of the germ cells in the testis from cancer treatment.Peer reviewe

Numerical simulation of strain-adaptive bone remodelling in the ankle joint

Background: The use of artificial endoprostheses has become a routine procedure for knee and hip joints while ankle arthritis has traditionally been treated by means of arthrodesis. Due to its advantages, the implantation of endoprostheses is constantly increasing. While finite element analyses (FEA) of strain-adaptive bone remodelling have been carried out for the hip joint in previous studies, to our knowledge there are no investigations that have considered remodelling processes of the ankle joint. In order to evaluate and optimise new generation implants of the ankle joint, as well as to gain additional knowledge regarding the biomechanics, strain-adaptive bone remodelling has been calculated separately for the tibia and the talus after providing them with an implant. Methods: FE models of the bone-implant assembly for both the tibia and the talus have been developed. Bone characteristics such as the density distribution have been applied corresponding to CT scans. A force of 5,200 N, which corresponds to the compression force during normal walking of a person with a weight of 100 kg according to Stauffer et al., has been used in the simulation. The bone adaptation law, previously developed by our research team, has been used for the calculation of the remodelling processes. Results: A total bone mass loss of 2% in the tibia and 13% in the talus was calculated. The greater decline of density in the talus is due to its smaller size compared to the relatively large implant dimensions causing remodelling processes in the whole bone tissue. In the tibia, bone remodelling processes are only calculated in areas adjacent to the implant. Thus, a smaller bone mass loss than in the talus can be expected. There is a high agreement between the simulation results in the distal tibia and the literature regarding. Conclusions: In this study, strain-adaptive bone remodelling processes are simulated using the FE method. The results contribute to a better understanding of the biomechanical behaviour of the ankle joint and hence are useful for the optimisation of the implant geometry in the future

Numerical investigations on the strain-adaptive bone remodelling in the periprosthetic femur: Influence of the boundary conditions

© 2009 Behrens et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Placental Apoptosis in Small for Gestational Age Babies: A Comparison between Swedish and Pakistani Populations

Background: Foeto-placental growth is regulated by a complex balance of growth promoting and growth inhibiting factors and hormones, namely the insulin-like growth factors (IGF) and the intracellular caspase proteins. Changes in the IGF-axis appear to affect this balance, with deficiencies possibly triggering apoptosis.Aim: To ascertain levels of apoptosis in the placenta of infants born small for gestational age (SGA) and appropriate for gestational age (AGA), comparing samples from two population groups, Pakistani and Swedish, in an attempt to better understand the mechanism behind foetal-placental growth restriction.Methods: Placental samples were taken immediately following delivery in both Karachi and Stockholm. In total 36 samples were included for further analysis (Pakistani: SGA n = 12, AGA n = 12; Swedish: SGA n = 7, AGA n = 5). Protein extraction was conducted for cell-death ELISA, and the remaining tissue samples were then paraffin embedded for further immunohistochemical and immunoflourescent analysis, looking at the apoptotic proteins, p53, caspase 8, and caspase 3. Furthermore, we compared maternal and newborn anthropometry between populations.Results: A higher apoptotic index, for caspase 8 and caspase 3, was seen in the Pakistani samples, as compared to the Swedish samples (p<0.01). TUNEL assays showed higher levels of apoptosis in the Pakistani population as compared to the Swedish population (p<0.01). Cell death ELISA analysis showed greater apoptotic activity in placenta from the Pakistani population as compared to the Swedish groups (p<0.05) as well as increased apoptotic activity in the SGA groups as compared to the AGA groups within each population (ELISA, p<0.05). No differences were seen in p53 levels as assessed by immunohistochemistry. Pakistani mothers were, on average, shorter than their Swedish counterparts (p<0.01).Conclusion: Increased apoptotic activity in placenta of the Pakistani population, as compared to their Swedish counterparts, may be associated with decreased foetal-placental growth seen in this population, particularly in babies born SGA. These findings, along with previously published results of the IGF-axis, and birth weight outcomes, suggests that lower IGF levels may be involved in the extracellular triggering of apoptosis, through caspase 8. This may further suggest a possible mechanism of foetal-placental growth restriction

Comparison between simulation results and DEXA investigation of the bone remodelling after implanting a cementless long stem hip prosthesis

Bone remodelling around a femoral prosthesis is one of the main reasons of aseptic loosening of the implant’s stem. The difference in stiffness between the bone tissue and the prosthesis leads to unload the periprosthetic bone and thus to decrease the bone mineral density (BMD), which is known as stress shielding. This paper represents a comparison between measured changes in (BMD) in a periprosthetic Femur with a cementless Bicontact stem by prospective dualenergy X-ray absorptiometry study (DEXA)and calculated changes of the (BMD) using a finite element method (FEM). As a result, it is determined that the total deviation between the two investigations is about 18%.DF

Testicular organoids: a new model to study the testicular microenvironment in vitro?

BACKGROUND: In recent decades, a broad range of strategies have been applied to model the testicular microenvironment in vitro. These models have been utilized to study testicular physiology and development. However, a system that allows investigations into testicular organogenesis and its impact in the spermatogonial stem-cell (SSC) niche in vitro has not been developed yet. Recently, the creation of tissue-specific organ-like structures called organoids has resurged, helping researchers to answer scientific questions that previous in vitro models could not help to elucidate. So far, a small number of publications have concerned the generation of testicular organoids and their application in the field of reproductive medicine and biology. OBJECTIVE AND RATIONALE: Here, we aim to elucidate whether testicular organoids might be useful in answering current scientific questions about the regulation and function of the SSC niche as well as germ cell proliferation and differentiation, and whether or not the existing in vitro models are already sufficient to address them. Moreover, we would like to discuss how an organoid system can be a better solution to address these prominent scientific problems in our field, by the creation of a rationale parallel to those in other areas where organoid systems have been successfully utilized. SEARCH METHODS: We comprehensively reviewed publications regarding testicular organoids and the methods that most closely led to the formation of these organ-like structures in vitro by searching for the following terms in both PubMed and the Web of Science database: testicular organoid, seminiferous tubule 3D culture, Sertoli cell 3D culture, testicular cord formation in vitro, testicular morphogenesis in vitro, germ cell 3D culture, in vitro spermatogenesis, testicular de novo morphogenesis, seminiferous tubule de novo morphogenesis, seminiferous tubule-like structures, testicular in vitro model and male germ cell niche in vitro, with no restrictions to any publishing year. The inclusion criteria were based on the relation with the main topic (i.e. testicular organoids, testicular- and seminiferous-like structures as in vitro models), methodology applied (i.e. in vitro culture, culture dimensions (2D, 3D), testicular cell suspension or fragments) and outcome of interest (i.e. organization in vitro). Publications about grafting of testicular tissue, germ-cell transplantation and female germ-cell culture were excluded. OUTCOMES: The application of organoid systems is making its first steps in the field of reproductive medicine and biology. A restricted number of publications have reported and characterized testicular organoids and even fewer have denominated such structures by this method. However, we detected that a clear improvement in testicular cell reorganization is recognized when 3D culture conditions are utilized instead of 2D conditions. Depending on the scientific question, testicular organoids might offer a more appropriate in vitro model to investigate testicular development and physiology because of the easy manipulation of cell suspensions (inclusion or exclusion of a specific cell population), the fast reorganization of these structures and the controlled in vitro conditions, to the same extent as with other organoid strategies reported in other fields. WIDER IMPLICATIONS: By way of appropriate research questions, we might use testicular organoids to deepen our basic understanding of testicular development and the SSC niche, leading to new methodologies for male infertility treatment

Self-organising human gonads generated by a Matrigel-based gradient system.

BACKGROUND: Advances in three-dimensional culture technologies have led to progression in systems used to model the gonadal microenvironment in vitro. Despite demonstrating basic functionality, tissue organisation is often limited. We have previously detailed a three-dimensional culture model termed the three-layer gradient system to generate rat testicular organoids in vitro. Here we extend the model to human first-trimester embryonic gonadal tissue. RESULTS: Testicular cell suspensions reorganised into testis-like organoids with distinct seminiferous-like cords situated within an interstitial environment after 7 days. In contrast, tissue reorganisation failed to occur when mesonephros, which promotes testicular development in vivo, was included in the tissue digest. Organoids generated from dissociated female gonad cell suspensions formed loosely organised cords after 7 days. In addition to displaying testis-specific architecture, testis-like organoids demonstrated evidence of somatic cell differentiation. Within the 3-LGS, we observed the onset of AMH expression in the cytoplasm of SOX9-positive Sertoli cells within reorganised testicular cords. Leydig cell differentiation and onset of steroidogenic capacity was also revealed in the 3-LGS through the expression of key steroidogenic enzymes StAR and CYP17A1 within the interstitial compartment. While the 3-LGS generates a somatic cell environment capable of supporting germ cell survival in ovarian organoids germ cell loss was observed in testicular organoids. CONCLUSION: The 3-LGS can be used to generate organised whole gonadal organoids within 7 days. The 3-LGS brings a new opportunity to explore gonadal organogenesis and contributes to the development of more complex in vitro models in the field of developmental and regenerative medicine

NASA Task Load Index (TLX) for IOS: an Essential Workload Measure in the Human Performance Toolbox

no abstract availabl