STUDY QUESTION Is it possible to co-culture and functionally link human liver and testis equivalents in the combined medium circuit of a multi-organ chip? SUMMARY ANSWER Multi-organ-chip co-cultures of human liver and testis equivalents were maintained at a steady-state for at least 1 week and the co-cultures reproduced specific natural and drug-induced liver–testis systemic interactions. WHAT IS KNOWN ALREADY Current benchtop reprotoxicity models typically do not include hepatic metabolism and interactions of the liver–testis axis. However, these are important to study the biotransformation of substances. STUDY DESIGN, SIZE, DURATION Testicular organoids derived from primary adult testicular cells and liver spheroids consisting of cultured HepaRG cells and hepatic stellate cells were loaded into separate culture compartments of each multi-organ-chip circuit for co-culture in liver spheroid-specific medium, testicular organoid-specific medium or a combined medium over a week. Additional multi-organ-chips (single) and well plates (static) were loaded only with testicular organoids or liver spheroids for comparison. Subsequently, the selected type of medium was supplemented with cyclophosphamide, an alkylating anti-neoplastic prodrug that has demonstrated germ cell toxicity after its bioactivation in the liver, and added to chip-based co-cultures to replicate a human liver–testis systemic interaction in vitro. Single chip-based testicular organoids were used as a control. Experiments were performed with three biological replicates unless otherwise stated. PARTICIPANTS/MATERIALS, SETTING, METHODS The metabolic activity was determined as glucose consumption and lactate production. The cell viability was measured as lactate dehydrogenase activity in the medium. Additionally, immunohistochemical and real-time quantitative PCR end-point analyses were performed for apoptosis, proliferation and cell-specific phenotypical and functional markers. The functionality of Sertoli and Leydig cells in testicular spheroids was specifically evaluated by measuring daily inhibin B and testosterone release, respectively. MAIN RESULTS AND THE ROLE OF CHANCE Co-culture in multi-organ chips with liver spheroid-specific medium better supported the metabolic activity of the cultured tissues compared to other media tested. The liver spheroids did not show significantly different behaviour during co-culture compared to that in single culture on multi-organ-chips. The testicular organoids also developed accordingly and produced higher inhibin B but lower testosterone levels than the static culture in plates with testicular organoid-specific medium. By comparison, testosterone secretion by testicular organoids cultured individually on multi-organ-chips reached a similar level as the static culture at Day 7. This suggests that the liver spheroids have metabolised the steroids in the co-cultures, a naturally occurring phenomenon. The addition of cyclophosphamide led to upregulation of specific cytochromes in liver spheroids and loss of germ cells in testicular organoids in the multi-organ-chip co-cultures but not in single-testis culture. LARGE-SCALE DATA N/A LIMITATIONS, REASONS FOR CAUTION The number of biological replicates included in this study was relatively small due to the limited availability of individual donor testes and the labour-intensive nature of multi-organ-chip co-cultures. Moreover, testicular organoids and liver spheroids are miniaturised organ equivalents that capture key features, but are still simplified versions of the native tissues. Also, it should be noted that only the prodrug cyclophosphamide was administered. The final concentration of the active metabolite was not measured. WIDER IMPLICATIONS OF THE FINDINGS This co-culture model responds to the request of setting up a specific tool that enables the testing of candidate reprotoxic substances with the possibility of human biotransformation. It further allows the inclusion of other human tissue equivalents for chemical risk assessment on the systemic level. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by research grants from the Scientific Research Foundation Flanders (FWO), Universitair Ziekenhuis Brussel (scientific fund Willy Gepts) and the Vrije Universiteit Brussel. Y.B. is a postdoctoral fellow of the FWO. U.M. is founder, shareholder and CEO of TissUse GmbH, Berlin, Germany, a company commercializing the Multi-Organ-Chip platform systems used in the study. The other authors have no conflict of interest to declare.
Increased frequencies of HEV infections have been reported in several industrialized countries. We suggest that this finding might be explained by a better awareness of the disease and not by an increased incidence. Although reported HEV infections increased more than 6-fold in Germany in recent years, the seroprevalence remained unchanged (2 %).
We report the first documented case of an extragestational infection with Chlamydophila abortus in humans. The pathogen was identified in a patient with severe pelvic inflammatory disease (PID) by sequence analysis of the ompA gene. Our findings raise the possibility that Chlamydiaceae other than Chlamydia trachomatis are involved in PID.
We previously reported a high degree of variation in the sensitivities of serodiagnostic kits for the detection of Chlamydophila pneumoniae in sera from healthy donors. Since a low predictive value of a test can impair its diagnostic value, we have extended our studies to samples from patients with pneumonia. We focused on the most promising enzyme-linked immunosorbent assays (ELISAs) (SeroCP and SeroCP Quant; Savyon) identified in our previous study and included a new ELISA (sELISA; Medac). The agreement between all ELISAs for immunoglobulin G (IgG) and a reference microimmunofluorescence (MIF) test for IgG (SeroFIA; Savyon) was >90% for a collective of 80 patients. The positive predictive values were all >93%. The negative predictive values ranged from 68 to 83%. False-negative results were obtained only for samples that had low titers in the MIF test. The correlation of the IgG antibody titers determined by the MIF and SeroCP Quant tests was high (r sp ؍ 0.9). Since the semiquantitative SeroCP and quantitative SeroCP Quant ELISAs achieved the highest sensitivities, they were evaluated further by using a second batch of sera from 50 patients with predominantly medium and low antibody titers in the MIF test and a control collection of sera from 80 children with negative MIF results. Again, the tests showed a high concordance with the MIF results (96%), and the antibody titers in the SeroCP Quant and MIF tests correlated well (r sp ؍ 0.8). The specificities determined with the negative sera were >99% for the SeroCP Quant test and 86% for the SeroCP test. These results show that ELISAs that are fast and objective deliver seroprevalence results, sensitivities, and specificities that are very similar to those of the MIF test.
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