193 research outputs found
Prolonged hypothyroidism severely reduces ovarian follicular reserve in adult rats
Background There is substantial evidence both in humans and in animals that a
prolonged reduction in plasma thyroid hormone concentration leads to
reproductive problems, including disturbed folliculogenesis, impaired
ovulation and fertilization rates, miscarriage and pregnancy complications.
The objective of the present study is to examine the consequences of chronic
hypothyroidism, induced in adulthood, for the size of the ovarian follicle
pool. In order to investigate this, adult female rats were provided either a
control or an iodide deficient diet in combination with perchlorate
supplementation to inhibit iodide uptake by the thyroid. Sixteen weeks later
animals were sacrificed. Blood was collected for hormone analyses and ovaries
were evaluated histologically. Results At the time of sacrifice, plasma
thyroid-stimulating hormone concentrations were 20- to 40-fold increased,
thyroxine concentrations were negligible while tri-iothyronin concentrations
were decreased by 40% in the hypothyroid group, confirming that the animals
were hypothyroid. Primordial, primary and preantral follicle numbers were
significantly lower in the hypothyroid ovaries compared to the euthyroid
controls, while a downward trend in antral follicle and corpora lutea numbers
was observed. Surprisingly the percentage of atretic follicles was not
significantly different between the two groups, suggesting that the reduced
preantral and antral follicle numbers were presumably not the consequence of
increased degeneration of these follicle types in the hypothyroid group.
Plasma anti-MĂĽllerian hormone (AMH) levels showed a significant correlation
with the growing follicle population represented by the total ovarian number
of primary, preantral and antral follicles, suggesting that also under
hypothyroid conditions AMH can serve as a surrogate marker to assess the
growing ovarian follicle population. Conclusions The induction of a chronic
hypothyroid condition in adult female rats negatively affects the ovarian
follicular reserve and the size of the growing follicle population, which may
impact fertility
Dual Effect on Adult-Type Leydig Cell and Sertoli Cell Development
Transient neonatal 6-propyl-2-thiouracil (PTU) induced hypothyroidism affects
Leydig and Sertoli cell numbers in the developing testis, resulting in
increased adult testis size. The hypothyroid condition was thought to be
responsible, an assumption questioned by studies showing that uninterrupted
fetal/postnatal hypothyroidism did not affect adult testis size. Here, we
investigated effects of transient hypothyroidism on Leydig and Sertoli cell
development, employing a perinatal iodide-deficient diet in combination with
sodium perchlorate. This hypothyroidism inducing diet was continued until days
1, 7, 14, or 28 postpartum (pp) respectively, when the rats were switched to a
euthyroid diet and followed up to adulthood. Continuous euthyroid and
hypothyroid, and neonatal PTU-treated rats switched to the euthyroid diet at
28 days pp, were included for comparison. No effects on formation of the
adult-type Leydig cell population or on Sertoli cell proliferation and
differentiation were observed when the diet switched at/or before day 14 pp.
However, when the diet was discontinued at day 28 pp, Leydig cell development
was delayed similarly to what was observed in chronic hypothyroid rats.
Surprisingly, Sertoli cell proliferation was 6- to 8-fold increased 2 days
after the diet switch and remained elevated the next days. In adulthood,
Sertoli cell number per seminiferous tubule cross-section and consequently
testis weight was increased in this group. These observations implicate that
increased adult testis size in transiently hypothyroid rats is not caused by
the hypothyroid condition per se, but originates from augmented Sertoli cell
proliferation as a consequence of rapid normalization of thyroid hormone
concentrations
Oncostatin-M inhibits luteinizing hormone stimulated Leydig cell progenitor formation in vitro
Background: The initial steps of stem Leydig cell differentiation into steroid producing progenitor cells are thought to take place independent of luteinizing hormone (LH), under the influence of locally produced factors such as leukaemia inhibitory factor (LIF), platelet derived growth factor A and stem cell factor. For the formation of a normal sized Leydig cell population in the adult testis, the presence of LH appears to be essential. Oncostatin M (OSM) is a multifunctional cytokine and member of the interleukin (IL)-6 family that also includes other cytokines such as LIF. In the rat OSM is highly expressed in the late fetal and neonatal testis, and may thus be a candidate factor involved in Leydig cell progenitor formation. Methods: Interstitial cells were isolated from 13-day-old rat testes and cultured for 1, 3 or 8 days in the presence of different doses of OSM ( range: 0.01 to 10 ng/ml) alone or in combination with LH ( 1 ng/ml). The effects of OSM and LH on cell proliferation were determined by incubating the cultures with [3H] thymidine or bromodeoxyuridine ( BrdU). Developing progenitor cells were identified histochemically by the presence of the marker enzyme 3beta-hydroxysteroid dehydrogenase (3beta-HSD). Results: OSM, when added at a dose of 10 ng/ml, caused a nearly 2-fold increase in the percentage of Leydig cell progenitors after 8 days of culture. Immunohistochemical double labelling experiments with 3beta-HSD and BrdU antibodies showed that this increase was the result of differentiation of stem Leydig cells/precursor cells and not caused by proliferation of progenitor cells themselves. The addition of LH to the cultures consistently resulted in an increase in progenitor formation throughout the culture period. Surprisingly, when OSM and LH were added together, the LH induced rise in progenitor cells was significantly inhibited after 3 and 8 days of culture. Conclusion: Taken together, the results of the present study suggest that locally produced OSM may not only play a role in the regulation of Sertoli cell proliferation and the initiation of spermatogenesis but may also play a role in the regulation of Leydig cell progenitor formation by keeping the augmenting effects of LH on this process in abeyance
Sex-specific and inter-individual differences in biomarkers of selenium status identified by a calibrated ELISA for selenoprotein P
Selenoprotein P (SELENOP) is a liver-derived transporter of selenium (Se) in
blood, and a meaningful biomarker of Se status. Se is an essential trace
element for the biosynthesis of enzymatically-active selenoproteins,
protecting the organism from oxidative damage. The usage of uncalibrated
assays hinders the comparability of SELENOP concentrations and their
pathophysiological interpretation across different clinical studies. On this
account, we established a new sandwich SELENOP-ELISA and calibrated against a
standard reference material (SRM1950). The ELISA displays a wide working range
(11.6–538.4 µg/L), high accuracy (2.9%) and good precision (9.3%). To verify
whether SELENOP correlates to total Se and to SELENOP-bound Se, serum samples
from healthy subjects and age-selected participants from the Berlin Aging
Study II were analyzed by SELENOP-ELISA and Se quantification. SELENOP was
affinity-purified and its Se content was determined from a subset of samples.
There was a high correlation of total Se and SELENOP concentrations in young
and elderly men, and in elderly women, but not in young women, indicating a
specific sexual dimorphism in these biomarkers of Se status in young subjects.
The Se content of isolated SELENOP was independent of sex and age (mean±SD:
5.4±0.5). By using this calibrated SELENOP-ELISA, prior reports on
pathological SELENOP concentrations in diabetes and obesity are challenged as
the reported values are outside reasonable limits. Biomarkers of Se status in
clinical research need to be measured by validated assays in order to avoid
erroneous data and incorrect interpretations, especially when analyzing young
women. The Se content of circulating SELENOP differs between individuals and
may provide some important diagnostic information on Se metabolism and status
Quality control and quantification in IG/TR next-generation sequencing marker identification: protocols and bioinformatic functionalities by EuroClonality-NGS
Item does not contain fulltex
Establishment of an Effective Radioiodide Thyroid Ablation Protocol in Mice
Due to the high variance in available protocols on iodide-131 ((131)I) ablation in rodents, we set out to establish an effective method to generate a thyroid-ablated mouse model that allows the application of the sodium iodide symporter (NIS) as a reporter gene without interference with thyroidal NIS. We tested a range of (131)I doses with and without prestimulation of thyroidal radioiodide uptake by a low-iodine diet and thyroid-stimulating hormone (TSH) application. Efficacy of induction of hypothyroidism was tested by measurement of serum T4 concentrations, pituitary TSH\textgreekb and liver deiodinase type 1 (DIO1) mRNA expression, body weight analysis, and (99m)Tc-pertechnetate scintigraphy. While 200 µCi (7.4 MBq) (131)I alone was not sufficient to abolish thyroidal T4 production, 500 µCi (18.5 MBq) (131)I combined with 1 week of a low-iodine diet decreased serum concentrations below the detection limit. However, the high (131)I dose resulted in severe side effects. A combination of 1 week of a low-iodine diet followed by injection of bovine TSH before the application of 150 µCi (5.5 MBq) (131)I decreased serum T4 concentrations below the detection limit and significantly increased pituitary TSH\textgreekb concentrations. The systemic effects of induced hypothyroidism were shown by growth arrest and a decrease in liver DIO1 expression below the detection limit. (99m)Tc-pertechnetate scintigraphy revealed absence of thyroidal (99m)Tc-pertechnetate uptake in ablated mice. In summary, we report a revised protocol for radioiodide ablation of the thyroid gland in the mouse to generate an in vivo model that allows the study of thyroid hormone action using NIS as a reporter gene
Sex-specific and inter-individual differences in biomarkers of selenium status identified by a calibrated ELISA for selenoprotein P
Selenoprotein P (SELENOP) is a liver-derived transporter of selenium (Se) in
blood, and a meaningful biomarker of Se status. Se is an essential trace
element for the biosynthesis of enzymatically-active selenoproteins,
protecting the organism from oxidative damage. The usage of uncalibrated
assays hinders the comparability of SELENOP concentrations and their
pathophysiological interpretation across different clinical studies. On this
account, we established a new sandwich SELENOP-ELISA and calibrated against a
standard reference material (SRM1950). The ELISA displays a wide working range
(11.6–538.4 µg/L), high accuracy (2.9%) and good precision (9.3%). To verify
whether SELENOP correlates to total Se and to SELENOP-bound Se, serum samples
from healthy subjects and age-selected participants from the Berlin Aging
Study II were analyzed by SELENOP-ELISA and Se quantification. SELENOP was
affinity-purified and its Se content was determined from a subset of samples.
There was a high correlation of total Se and SELENOP concentrations in young
and elderly men, and in elderly women, but not in young women, indicating a
specific sexual dimorphism in these biomarkers of Se status in young subjects.
The Se content of isolated SELENOP was independent of sex and age (mean±SD:
5.4±0.5). By using this calibrated SELENOP-ELISA, prior reports on
pathological SELENOP concentrations in diabetes and obesity are challenged as
the reported values are outside reasonable limits. Biomarkers of Se status in
clinical research need to be measured by validated assays in order to avoid
erroneous data and incorrect interpretations, especially when analyzing young
women. The Se content of circulating SELENOP differs between individuals and
may provide some important diagnostic information on Se metabolism and status
Next-generation sequencing of immunoglobulin gene rearrangements for clonality assessment: a technical feasibility study by EuroClonality-NGS
Item does not contain fulltex
Testing for heterotopia formation in rats after developmental exposure to selected in vitro inhibitors of thyroperoxidase
© 2021 The Authors. The thyroperoxidase (TPO) enzyme is expressed by the thyroid follicular cells and is required for thyroid hormone synthesis. In turn, thyroid hormones are essential for brain development, thus inhibition of TPO in early life can have life-long consequences for brain function. If environmental chemicals with the capacity to inhibit TPO in vitro can also alter brain development in vivo through thyroid hormone dependent mechanisms, however, remains unknown. In this study we show that the in vitro TPO inhibiting pesticide amitrole alters neuronal migration and induces periventricular heterotopia; a thyroid hormone dependent brain malformation. Perinatal exposure to amitrole reduced pup serum thyroxine (T4) concentrations to less than 50% of control animals and this insufficiency led to heterotopia formation in the 16-day old pup's brain. Two other in vitro TPO inhibitors, 2-mercaptobenzimidazole and cyanamide, caused reproductive toxicity and had only minor sporadic effects on the thyroid hormone system; consequently, they did not cause heterotopia. This is the first demonstration of an environmental chemical causing heterotopia, a brain malformation until now only reported for rodent studies with the anti-thyroid drugs propylthiouracil and methimazole. Our results highlight that certain TPO-inhibiting environmental chemicals can alter brain development through thyroid hormone dependent mechanisms. Improved understanding of the effects on the brain as well as the conditions under which chemicals can perturb brain development will be key to protect human health.ATHENA project (Assays for the identification of Thyroid Hormone axis-disrupting chemicals: Elaborating Novel assessment strategies); (Kortenkamp et al., 2020) funded by the EU Horizon 2020 programme, grant number 825161
ARResT/Interrogate: an interactive immunoprofiler for IG/TR NGS data.
Abstract
Motivation
The study of immunoglobulins and T cell receptors using next-generation sequencing has finally allowed exploring immune repertoires and responses in their immense variability and complexity. Unsurprisingly, their analysis and interpretation is a highly convoluted task.
Results
We thus implemented ARResT/Interrogate, a web-based, interactive application. It can organize and filter large amounts of immunogenetic data by numerous criteria, calculate several relevant statistics, and present results in the form of multiple interconnected visualizations.
Availability and Implementation
ARResT/Interrogate is implemented primarily in R, and is freely available at http://bat.infspire.org/arrest/interrogate/
Supplementary information
Supplementary data are available at Bioinformatics online
- …