Showing papers by "Thomas B. Hildebrandt published in 2018"

Species comparison of liver proteomes reveals links to naked mole-rat longevity and human aging

Abstract: Mammals display a wide range of variation in their lifespan. Investigating the molecular networks that distinguish long- from short-lived species has proven useful to identify determinants of longevity. Here, we compared the livers of young and old long-lived naked mole-rats (NMRs) and the phylogenetically closely related, shorter-lived, guinea pigs using an integrated omics approach. We found that NMR livers display a unique expression pattern of mitochondrial proteins that results in distinct metabolic features of their mitochondria. For instance, we observed a generally reduced respiration rate associated with lower protein levels of respiratory chain components, particularly complex I, and increased capacity to utilize fatty acids. Interestingly, we show that the same molecular networks are affected during aging in both NMRs and humans, supporting a direct link to the extraordinary longevity of both species. Finally, we identified a novel detoxification pathway linked to longevity and validated it experimentally in the nematode Caenorhabditis elegans. Our work demonstrates the benefits of integrating proteomic and transcriptomic data to perform cross-species comparisons of longevity-associated networks. Using a multispecies approach, we show at the molecular level that livers of NMRs display progressive age-dependent changes that recapitulate typical signatures of aging despite the negligible senescence and extraordinary longevity of these rodents.

A Cross-Sectional Multicenter Study of Multidimensional Body Image in Adolescents and Adults with Gender Dysphoria Before and After Transition-Related Medical Interventions.

Abstract: Persistent feelings of gender dysphoria (GD) are accompanied by distress and body dissatisfaction in most clinically referred adolescents and adults. Transition-related medical interventions (e.g., puberty suppression, hormones, or surgery) may alleviate body dissatisfaction. The aim of the present cross-sectional study was to compare multidimensional body image across clinically referred adolescents and adults undergoing different transition-related medical interventions. Two clinical samples of adolescents (n = 82) and adults (n = 120) referred to specialized departments of four different transgender health services in Germany participated in the study. In total, 202 individuals from the female-to-male (FtM individuals) and male-to-female (MtF individuals) spectrum aged 14–74 years were included at different stages of their transition. Four scales assessing multidimensional aspects of body image (measured by the Body Image Assessment Questionnaire, FBeK) were compared across three groups: sample, gender, and medical interventions (while controlling for age and treatment duration). The results indicated less favorable body image scores compared with the norm in both adolescents and adults with GD. Individuals who had undergone transition-related medical interventions presented a significantly better body image on two of the four scales. Differences according to gender and age were also present. These findings suggest that medical interventions, especially gender-affirming hormones and surgery, are generally beneficial to the body image in individuals with GD. However, not all of the less favorable outcomes in multidimensional body image were positively influenced by the treatment conditions and may thus benefit from additional integrative counseling before and during transition.

Long-lived rodents reveal signatures of positive selection in genes associated with lifespan.

Abstract: The genetics of lifespan determination is poorly understood. Most research has been done on short-lived animals and it is unclear if these insights can be transferred to long-lived mammals like humans. Some African mole-rats (Bathyergidae) have life expectancies that are multiple times higher than similar sized and phylogenetically closely related rodents. To gain new insights into genetic mechanisms determining mammalian lifespans, we obtained genomic and transcriptomic data from 17 rodent species and scanned eleven evolutionary branches associated with the evolution of enhanced longevity for positively selected genes (PSGs). Indicating relevance for aging, the set of 250 identified PSGs showed in liver of long-lived naked mole-rats and short-lived rats an expression pattern that fits the antagonistic pleiotropy theory of aging. Moreover, we found the PSGs to be enriched for genes known to be related to aging. Among these enrichments were "cellular respiration" and "metal ion homeostasis", as well as functional terms associated with processes regulated by the mTOR pathway: translation, autophagy and inflammation. Remarkably, among PSGs are RHEB, a regulator of mTOR, and IGF1, both central components of aging-relevant pathways, as well as genes yet unknown to be aging-associated but representing convincing functional candidates, e.g. RHEBL1, AMHR2, PSMG1 and AGER. Exemplary protein homology modeling suggests functional consequences for amino acid changes under positive selection. Therefore, we conclude that our results provide a meaningful resource for follow-up studies to mechanistically link identified genes and amino acids under positive selection to aging and lifespan determination.

Optimized DNA sampling of ancient bones using Computed Tomography scans.

Abstract: The prevalence of contaminant microbial DNA in ancient bone samples represents the principal limiting factor for palaeogenomic studies, as it may comprise more than 99% of DNA molecules obtained. Efforts to exclude or reduce this contaminant fraction have been numerous but also variable in their success. Here, we present a simple but highly effective method to increase the relative proportion of endogenous molecules obtained from ancient bones. Using computed tomography (CT) scanning, we identify the densest region of a bone as optimal for sampling. This approach accurately identifies the densest internal regions of petrous bones, which are known to be a source of high-purity ancient DNA. For ancient long bones, CT scans reveal a high-density outermost layer, which has been routinely removed and discarded prior to DNA extraction. For almost all long bones investigated, we find that targeted sampling of this outermost layer provides an increase in endogenous DNA content over that obtained from softer, trabecular bone. This targeted sampling can produce as much as 50-fold increase in the proportion of endogenous DNA, providing a directly proportional reduction in sequencing costs for shotgun sequencing experiments. The observed increases in endogenous DNA proportion are not associated with any reduction in absolute endogenous molecule recovery. Although sampling the outermost layer can result in higher levels of human contamination, some bones were found to have more contamination associated with the internal bone structures. Our method is highly consistent, reproducible and applicable across a wide range of bone types, ages and species. We predict that this discovery will greatly extend the potential to study ancient populations and species in the genomics era.

Naked mole-rat transcriptome signatures of socially suppressed sexual maturation and links of reproduction to aging

Abstract: Naked mole-rats (NMRs) are eusocially organized in colonies. Although breeders carry the additional metabolic load of reproduction, they are extremely long-lived and remain fertile throughout their lifespan. This phenomenon contrasts the disposable soma theory of aging stating that organisms can invest their resources either in somatic maintenance, enabling a longer lifespan, or in reproduction, at the cost of longevity. Here, we present a comparative transcriptome analysis of breeders vs. non-breeders of the eusocial, long-lived NMR vs. the polygynous and shorter-lived guinea pig (GP). Comparative transcriptome analysis of tissue samples from ten organs showed, in contrast to GPs, low levels of differentiation between sexes in adult NMR non-breeders. After transition into breeders, NMR transcriptomes are markedly sex-specific, show pronounced feedback signaling via gonadal steroids, and have similarities to reproductive phenotypes in African cichlid fish, which also exhibit social status changes between dominant and subordinate phenotypes. Further, NMRs show functional enrichment of status-related expression differences associated with aging. Lipid metabolism and oxidative phosphorylation—molecular networks known to be linked to aging—were identified among most affected gene sets. Remarkably and in contrast to GPs, transcriptome patterns associated with longevity are reinforced in NMR breeders. Our results provide comprehensive and unbiased molecular insights into interspecies differences between NMRs and GPs, both in sexual maturation and in the impact of reproduction on longevity. We present molecular evidence that sexual maturation in NMRs is socially suppressed. In agreement with evolutionary theories of aging in eusocial organisms, we have identified transcriptome patterns in NMR breeders that—in contrast to the disposable soma theory of aging—may slow down aging rates and potentially contribute to their exceptional long life- and healthspan.

Retraction Note: Improving usability and pregnancy rates of a fertility monitor by an additional mobile application: results of a retrospective efficacy study of Daysy and DaysyView app.

Abstract: Daysy is a fertility monitor that uses the fertility awareness method by tracking and analyzing the individual menstrual cycle. In addition, Daysy can be connected to the application DaysyView to transfer stored personal data from Daysy to a smartphone or tablet (IOS, Android). This combination is interesting because as it is shown in various studies, the use of apps is increasing patients´ focus on their disease or their health behavior. The aim of this study was to investigate if by the additional use of an App and thereby improved usability of the medical device, it is possible to enhance the typical-use related as well as the method-related pregnancy rates. In the resultant group of 125 women (2076 cycles in total), 2 women indicated that they had been unintentionally pregnant during the use of the device, giving a typical-use related Pearl-Index of 1.3. Counting only the pregnancies which occurred as a result of unprotected intercourse during the infertile (green) phase, we found 1 pregnancy, giving a method-related Pearl-Index of 0.6. Calculating the pregnancy rate resulting from continuous use and unprotected intercourse exclusively on green days, gives a perfect-use Pearl-Index of 0.8. It seems that combining a specific biosensor-embedded device (Daysy), which gives the method a very high repeatable accuracy, and a mobile application (DaysyView) which leads to higher user engagement, results in higher overall usability of the method.

Species comparison of liver proteomes reveals links to naked mole-rat longevity and human aging

Abstract: Mammals display wide range of variation in their lifespan. Investigating the molecular networks that distinguish long- from short-lived species has proven useful to identify determinants of longevity. Here, we compared the liver of long-lived naked mole-rats (NMRs) and the phylogenetically closely related, shorter-lived, guinea pigs using an integrated omic approach. We found that NMRs livers display a unique expression pattern of mitochondrial proteins that result in distinct metabolic features of their mitochondria. For instance, we observed a generally reduced respiration rate associated with lower protein levels of respiratory chain components, particularly complex I, and increased capacity to utilize fatty acids. Interestingly, we show that the same molecular networks are affected during aging in both NMR and humans, supporting a direct link to the extraordinary longevity of both species. Finally, we identified a novel longevity pathway and validated it experimentally in the nematode C. elegans.

Cryopreservation in rhinoceros-Setting a new benchmark for sperm cryosurvival.

Abstract: At times when rhinoceros are fiercely poached, when some rhinoceros species are closer than ever to extinction, and when the scientific community is in debate over the use of advanced cell technologies as a remaining resort it is time to simplify and improve existing assisted reproduction techniques to enhance breeding and genetic diversity in the living populations under our care Semen cryopreservation has been performed in all captive rhinoceros species with limited degree of success Here we tested three freezing extenders, containing different cryoprotectants and various freezing rates for the cryopreservation of rhinoceros sperm from 14 bulls In experiment I, semen from 9 bulls was used to determine the most suitable diluent, cryoprotectant and freezing rate for the successful cryopreservation of rhinoceros sperm In experiment II, semen from 5 bulls was used to assess whether the removal of seminal plasma could further improve post thaw sperm quality following cryopreservation with conditions identified in Experiment I Semen was diluted with Berliner Cryomedia, ButoCrio® or INRA Freeze®, packaged in 05 mL straws and frozen 3, 4, and 5 cm over liquid nitrogen (LN) vapour or directly in a dryshipper It was found that semen extended with ButoCrio® (containing glycerol and methylformamide) and frozen 3cm over LN vapour provided the best protection to rhinoceros spermatozoa during cryopreservation When pooled over treatments, total and progressive post thaw motility was 753 ± 42% and 685 ± 57%, respectively marking a new benchmark for the cryopreservation of rhinoceros sperm Post thaw total and progressive motility, viability and acrosome integrity of semen diluted in ButoCrio® was significantly higher than semen extended in Berliner Cryomedia or INRA Freeze® The removal of seminal plasma did not improve post thaw sperm survival (p > 005) In conclusion, the cryosurvival of rhinoceros spermatozoa was significantly improved when using a mixture of glycerol and methylformamide in combination with a fast freezing rate at 3 cm These results describe a new protocol for the improved cryosurvival of rhinoceros spermatozoa and will enable a more successful preservation of genetic diversity between males, especially in donors whose spermatozoa may already be compromised prior to or during collection The successful reduction of glycerol concentration in favour of methylformamide as a cryoprotectant could be a novel suggestion for the improvement of cryopreservation techniques in other wildlife species

Major and minor complications after resection without bowel resection for deeply infiltrating endometriosis

Abstract: To analyze major and minor complications following surgery for deeply infiltrating endometriosis including long-term impairment of intestinal, bladder, and sexual function. Patients who had undergone resection for deeply infiltrating endometriosis without anterior rectal resection between 2001 and 2011 were included (n = 134). Clinical and surgical data, as well as minor and major complications, were recorded. A questionnaire was sent to the patients and to a healthy control group (n = 100). Major complications occurred in 3.7% and minor complications in 12.7% of the patients. Surgical revision was necessary in five cases. The questionnaire response rate was 66.4%, with a mean follow-up period of 75.6 months. Weak urinary flow was reported by 26.4% of the patients; a feeling of residual urine by 16.1%; constipation by 13.5%; more than one bowel movement/day by 16.9%; insufficient lubrication during intercourse by 30.3%. The findings for weak urinary flow, feeling of residual urine, and insufficient lubrication differed significantly from the control group. Subgroup analysis did not identify any statistical associations between questionnaire responses and dyspareunia or dysmenorrhea as reasons for surgery, or previous endometriosis surgery in the patient’s history. The major and minor complication rates were consistent with or lower than the literature data. Few studies have investigated complication rates associated with treatment for endometriosis in the sacrouterine ligaments and/or the rectovaginal septum. The high rates of impaired bladder function and sexual function after endometriosis surgery, as well as inadequate data, make further prospective studies on this topic necessary.

Bronchoalveolar lavage for diagnosis of tuberculosis infection in elephants.

Abstract: Tuberculosis (TB) has been known to affect elephants for thousands of years. It was put into spotlight when few circus elephants were diagnosed carrying Mycobacterium (M.) tuberculosis. Because of the zoonotic risk and high susceptibility to M. tuberculosis, periodic testing was enacted since, in captive breeding programmes. Presently, trunk wash is the recommended diagnostic procedure for TB. Trunk wash, however, puts the operator at risk, has low sensitivity, and is prone to contamination. Here, bronchoalveolar lavage is described for the first time for TB diagnosis in elephants. Bronchial, trunk and mouth fluids were investigated using bacterial culture, M. tuberculosis complex (MTC)-specific real-time quantitative PCR (qPCR) and mycobacterial genus-specific qPCR for overall presence of mycobacteria or mycobacterial DNA including bacteria or DNA of closely related genera, respectively, in 14 elephants. Neither bacteria of the MTC nor their DNA were identified in any of the elephants. Yet, 25% of the cultures grew non-tuberculous mycobacteria (NTM) or closely related bacterial species. Furthermore, 85% of the samples contained DNA of NTM or closely related bacterial genera. This finding might explain continued false-positive results from various serological tests. From a zoonotic point of view, bronchoalveolar lavage is safer for the testing personal, has higher probability of capturing MTC and, through PCR, identifies DNA NTM in elephants. Yet, necessary endoscopic equipment, animal sedation and access to a TB reference laboratory might pose challenging requirements in remote conditions in some elephant range countries.

Development to term of sheep embryos reconstructed after inner cell mass/trophoblast exchange.

Abstract: Here we report in vitro and term development of sheep embryos after the inner cell mass (ICM) from one set of sheep blastocysts were injected into the trophoblast vesicles of another set. We also observed successful in vitro development of chimeric blastocysts made from sheep trophoblast vesicles injected with bovine ICM. First, we dissected ICMs from 35 sheep blastocysts using a stainless steel microblade and injected them into 29 re-expanded sheep trophoblastic vesicles. Of the 25 successfully micromanipulated trophoblastic vesicles, 15 (51.7%) re-expanded normally and showed proper ICM integration. The seven most well reconstructed embryos were transferred for development to term. Three ewes receiving manipulated blastocysts were pregnant at day 45 (42.8%), and all delivered normal offspring (singletons, two females and one male, average weight: 3.54 ± 0.358 kg). Next, we monitored in vitro development of sheep trophoblasts injected with bovine ICMs. Of 17 injected trophoblastic vesicles, 10 (58.8%) re-expanded after 4 h in culture, and four (40%) exhibited integrated bovine ICM. Our results indicate that ICM/trophoblast exchange is feasible, allowing full term development with satisfactory lambing rate. Therefore, ICM exchange is a promising approach for endangered species conservation.

Differential detection of tuberculous and non-tuberculous mycobacteria by qPCR in lavage fluids of tuberculosis-suspicious white rhinoceros.

Abstract: Tuberculosis (TB) occurs in a wide range of mammalian species and thus poses a health risk to humans living or working in close proximity with TB infected animals. Despite a high incidence of M. bovis infections in domestic or wildlife species tuberculosis infections in rhinoceros have so far been very limited. Over the past 53 years, tuberculosis of the respiratory tract has been confirmed in just 22 rhinoceros, most of those infected not by M. bovis but M. tuberculosis. However, because of the zoonotic risk TB testing is recommended or becomes even mandatory in endangered species. The dilemma in rhinoceros and many other wildlife species; non-validated tests are highly inconsistent in their ability to identify TB infection. Current lack of TB diagnostics may result in TB positive rhinoceros living with the infection, transmitting it to those around them or in euthanasia of animals found unconfirmed at necropsy. This is an unacceptable diagnostic status considering that some species are critically endangered and therefore should not be euthanized in order to confirm suspicion of disease. To overcome this shortcoming we used bronchoscopy to detect mycobacteria in respiratory fluids of TB suspicious rhinoceros. Fluids from seven, TB suspicious white rhinoceros were harvested during 21 bronchoscopies. Our new approach: In addition to bacterial culture a dual quantitative PCR system tested for the general presence of DNA from NTM and more specifically for DNA from MTC. Both, bacterial culture and qPCR were negative for MTC in respiratory fluids of all rhinoceros (7/7). At the same time, respiratory fluids from six rhinoceros tested positive for the presence of NTM or other closely related bacteria (6/7). M. tuberculosis was found only once in an oesophageal aspirate. The high incidence of mycobacterial DNA in the respiratory tract suggests that white rhinoceros, as strict grazers, are immensely exposed to environmental bacteria of this genus. Presence of NTM in the respiratory or intestinal system could possibly cause false positive results in intradermal tests. A wider use of bronchoalveolar lavage is warranted to further elucidate immunologic response to NTM and exposure to, incidence and prevalence of MTC infections in rhinoceros.

Total laparoscopic hysterectomy: how does training for surgeons in a standardized operation affect hospitals and patients?

Abstract: Surgical training usually means inexperienced physicians initially doing operations supervised by an experienced physician, to gain the experience and skills needed to conduct surgery independently. Various issues arise here for both hospitals and patients. Are training procedures associated with higher complication rates, blood losses, and transfusion rates? What does training in the operating room ultimately cost in terms of valuable surgical time? Do longer hospitalization periods potentially mean financial losses for the hospital under the diagnosis-related groups (DRG) system? A retrospective analysis was carried out of data for 571 patients who underwent total laparoscopic hysterectomy (TLH) in the Department of Gynecology at the University of Erlangen from 2009 to 2012, with/without adnexectomy, due to benign indication; and of data for 255 patients who underwent the same procedures in Karlsruhe Municipal Hospital in 2013–2014. The patients were classified into two groups: those in whom surgery was carried out by experienced specialists who had carried out at least 40 independent operations; and those in whom it was carried out by a trainee resident who had personally done fewer than 40 operations. In the two groups, the patients had similar mean body mass indexes, uterus weights, and blood losses. Patients in the specialist group were slightly older. There were no differences in complication rates. Over two-thirds of complications occurred in patients with previous surgery. Procedures by residents took significantly longer. Hospitalization periods in both groups were still below the mean threshold length of stay under Germany’s DRG system, so that no income losses occurred even with training procedures. Training and teaching operations supervised by experienced surgeons are just as safe as operations by experienced surgeons themselves. Interpretation of these data is of course limited by the retrospective study design; patients treated by specialists tended to have more prior operations and were older, with a trend toward larger uteri. Surgical training, as the example of TLH in benign indication shows here, involves an additional time of approximately 10–20 min per operation. With regard to the revenue situation, the hospitalization periods in both groups were within the profit zone for the hospital concerned.