You are looking at 41 - 50 of 13,983 items for

  • All content x
Clear All
Restricted access

Giselle Adriana Abruzzese, Maria Florencia Heber, Silvana Rocío Ferreira, María José Ferrer, and Alicia Beatriz Motta

Prenatal androgen exposure affects reproductive functions and has been proposed as an underlying cause of polycystic ovary syndrome (PCOS). In this study, we aimed to investigate the impact of prenatal androgen exposure on ovarian lipid metabolism and to deepen our understanding of steroidogenesis regulation during adulthood. Pregnant rats were hyperandrogenized with testosterone and female offspring were studied when adult. This treatment leads to two different phenotypes: irregular ovulatory and anovulatory animals. Our results showed that prenatally hyperandrogenized (PH) animals displayed altered lipid and hormonal profile together with alterations in steroidogenesis and ovarian lipid metabolism. Moreover, PH animals showed alterations in the PPARg system, impaired mRNA levels of cholesterol receptors (Ldlr and Srb1) and decreased expression of the rate-limiting enzyme of de novo cholesterol production (Hmgcr). Anovulatory PH animals presented an increase of ovarian cholesteryl esters levels and lipid peroxidation index. Together with alterations in cholesterol metabolism, we found an impairment of the steroidogenic pathway in PH animals in a phenotype-specific manner. Regarding fatty acid metabolism, our results showed, in PH animals, an altered expression of Srebp1 and Atgl, which are involved in fatty acid metabolism and triglycerides hydrolysis, respectively. In conclusion, fatty acid and cholesterol metabolism, which are key players in steroidogenesis acting as a source of energy and substrate for steroid production, were affected in animals exposed to androgens during gestation. These results suggest that prenatal androgen exposure leads to long-term effects that affect ovary lipid metabolism and ovarian steroid formation from the very first steps.

Restricted access

Lei Du, Yang Wang, Cong-Rong Li, Liang-Jian Chen, Jin-Yang Cai, Zheng-Rong Xia, Wen-Tao Zeng, Zi-Bin Wang, Xi-Chen Chen, Fan Hu, Dong Zhang, Xiao-Wei Xing, and Zhi-Xia Yang

Polycystic ovarian syndrome (PCOS) is a major severe ovary disorder affecting 5–10% of reproductive women around the world. PCOS can be considered a metabolic disease because it is often accompanied by obesity and diabetes. Brown adipose tissue (BAT) contains abundant mitochondria and adipokines and has been proven to be effective for treating various metabolic diseases. Recently, allotransplanted BAT successfully recovered the ovarian function of PCOS rat. However, BAT allotransplantation could not be applied to human PCOS; the most potent BAT is from infants, so voluntary donors are almost inaccessible. We recently reported that single BAT xenotransplantation significantly prolonged the fertility of aging mice and did not cause obvious immunorejection. However, PCOS individuals have distinct physiologies from aging mice; thus, it remains essential to study whether xenotransplanted rat BAT can be used for treating PCOS mice. In this study, rat-to-mouse BAT xenotransplantation fortunately did not cause severe rejection reaction, and significantly recovered ovarian functions, indicated by the recovery of fertility, oocyte quality, and the levels of multiple essential genes and kinases. Besides, the blood biochemical index, glucose resistance, and insulin resistance were improved. Moreover, transcriptome analysis showed that the recovered PCOS F0 mother following BAT xenotransplantation could also benefit the F1 generation. Finally, BAT xenotransplantation corrected characteristic gene expression abnormalities found in the ovaries of human PCOS patients. These findings suggest that BAT xenotransplantation could be a novel therapeutic strategy for treating PCOS patients.

Restricted access

Lucie E Bourne, Caroline P Wheeler-Jones, and Isabel R Orriss

Biomineralisation, the deposition of mineral onto a matrix, can be both a physiological and pathological process. Bone formation involves the secretion of an extracellular matrix (ECM) by osteoblasts and subsequent mineralisation of that matrix. It is regulated by a number of local and systemic factors and is necessary for maintenance of normal bone health. Conversely, mineralisation (or calcification) of soft tissues, including the vasculature, is detrimental to that tissue, leading to diseases such as arterial medial calcification (AMC). The mechanisms underlying AMC development are not fully defined, though it is thought that vascular smooth muscle cells (VSMCs) drive this complex, cell-mediated process. Similarly, AMC is regulated by a variety of enzymes and molecules, many of which have already been implicated in the regulation of bone mineralisation. This review will provide an overview of the similar, and sometimes opposing effects of these signalling molecules on the regulation of bone mineralisation and AMC.

Restricted access

Ana Sánchez-Tusie, Carlos Montes de Oca, Julia Rodríguez-Castelán, Evangelina Delgado-González, Zamira Ortiz, Lourdes Álvarez, Carlos Zarco, Carmen Aceves, and Brenda Anguiano

Thyroxine (T4) promotes cell proliferation and tumor growth in prostate cancer models, but it is unknown if the increase in the triiodothyronine (T3)/T4 ratio could attenuate prostate tumor development. We assessed T3 effects on thyroid response, histology, proliferation, and apoptosis in the prostate of wild-type (WT) and TRAMP (transgenic adenocarcinoma of the mouse prostate) mice. Physiological doses of T3 were administered in the drinking water (2.5, 5 and 15 µg/100 g body weight) for 6 weeks. None of the doses modified the body weight or serum levels of testosterone, but all of them reduced serum T4 levels by 50%, and the highest dose increased the T3/T4 ratio in TRAMP. In WT, the highest dose of T3 decreased cyclin D1 levels (immunohistochemistry) but did not modify prostate weight or alter the epithelial morphology. In TRAMP, this dose reduced tumor growth by antiproliferative mechanisms independent of apoptosis, but it did not modify the intraluminal or fibromuscular invasion of tumors. In vitro, in the LNCaP prostate cancer cell line, we found that both T3 and T4 increased the number of viable cells (Trypan blue assay), and only T4 response was fully blocked in the presence of an integrin-binding inhibitor peptide (RGD, arginine-glycine-aspartate). In summary, our data show that the prostate was highly sensitive to physiological T3 doses and suggest that in vivo, an increase in the T3/T4 ratio could be associated with the reduced weight of prostate tumors. Longitudinal studies are required to understand the role of thyroid hormones in prostate cancer progression.

Restricted access

Patrycja Kurowska, Ewa Mlyczyńska, Monika Dawid, Małgorzata Grzesiak, Joelle Dupont, and Agnieszka Rak

Vaspin, visceral adipose tissue-derived serine protease inhibitor, plays important roles in inflammation, obesity, and glucose metabolism. Our recent research has shown the expression and role of vaspin in the function of ovarian follicles. However, whether vaspin regulates steroidogenesis and luteolysis in the corpus luteum (CL) is still unknown. The aim of this study was first to determine the expression of vaspin and its receptor GRP78 in porcine CL at the early, middle, and late stages of the luteal phase. Next, we investigated the hormonal regulation of vaspin levels in luteal cells in response to luteinizing hormone (LH), progesterone (P4), and prostaglandin PGE2 and PGF2α. Finally, we determined vaspin’s direct impact on luteal cells steroidogenesis, luteolysis and kinases phosphorylation. Our results are the first to show higher vaspin/GRP78 expression in middle and late vs early stages; immunohistochemistry showed cytoplasmic vaspin/GRP78 localization in small and large luteal cells. In vitro, we found that LH, P4, PGE2, and PGF2α significantly decreased vaspin levels. Furthermore, vaspin stimulated steroidogenesis by the activation of the GRP78 receptor and protein kinase A (PKA). Also, vaspin increased the ratio of luteotropic PGE2 to luteolytic PGF2α secretion via GRP78 and mitogen-activated kinase (MAP3/1). Moreover, vaspin, in a dose-dependent manner, decreased GRP78 expression, while it, in a time-dependent manner, increased kinases PKA and MAPK3/1 phosphorylation. Taken together, we found that vaspin/GRP78 expression depends on the luteal phase stage and vaspin affects luteal cells endocrinology, indicating that vaspin is a new regulator of luteal cells steroidogenesis and CL formation.

Restricted access

Tiffany K Miles, Ana Rita Silva Moreira, Melody L Allensworth-James, Angela K Odle, Anessa C Haney, Angus M MacNicol, Melanie C MacNicol, and Gwen V Childs

Anterior pituitary somatotropes are important metabolic sensors responding to leptin by secreting growth hormone (GH). However, reduced leptin signals caused by fasting have not always correlated with reduced serum GH. Reports show that fasting may stimulate or reduce GH secretion, depending on the species. Mechanisms underlying these distinct somatotrope responses to fasting remain unknown. To define the somatotrope response to decreased leptin signaling we examined markers of somatotrope function over different time periods of fasting. Male mice were fasted for 24 and 48 h, with female mice fasted for 24 h compared to fed controls ad libitum. Body weight and serum glucose were reduced in both males and females, but, unexpectedly, serum leptin was reduced only in males. Furthermore, in males, serum GH levels showed a biphasic response with significant reductions at 24 h followed by a significant rise at 48 h, which coincided with the rise in serum ghrelin levels. In contrast, females showed an increase in serum GH at 24 h. We then explored mechanisms underlying the differential somatotrope responses seen in males and observed that pituitary levels of Gh mRNA increased, with no distinction between acute and prolonged fasting. By contrast, the Ghrhr mRNA (encoding GH releasing hormone receptor) and the Ghsr mRNA (encoding the ghrelin receptor) were both greatly increased at prolonged fasting times coincident with increased serum GH. These findings show sex differences in the somatotrope and adipocyte responses to fasting and support an adaptive role for somatotropes in males in response to multiple metabolic signals.

Restricted access

Weihua Liu, Yuqiang Ji, Haiping Chu, Mo Wang, Bin Yang, and Chunyan Yin

This study investigated the effects of Wnt5a/caveolin/JNK signaling pathway and SFRP5 protein on ox-LDL-induced apoptosis of HUVEC cells. The difference of serological indexes between healthy average weight and obese children and the expression of Wnt 5a and SFRP5 was detected by clinical examination, and the correlation between serum SFRP5, Wnt 5a and the vascular endothelial injury was detected. HUVEC cells were induced by ox-LDL to construct an endothelial injury model, siRNA-transfected cells were used to construct downregulated SFRP5 and Wnt 5a expression groups, and recombination methods were used to construct upregulated Wnt5a and SFRP5 expression groups. The expression of Wnt 5a, caveolin-1, JNK and apoptosis-related proteins under different treatments were detected by the Western blot method, and apoptosis was detected by flow cytometry. Serological results showed that the level of Sfrp5 in obese children was significantly lower than that in healthy children, and the level of Wnt5a was significantly higher than that in healthy children. Moreover, Ln Sfrp5 was significantly negatively correlated with Ang-2 in blood circulation, ICAM-1 and E-selectin selectin, but not with VCAM-1. When Wnt5a was upregulated, the expression of caveolin-1 and JNK increased significantly, Bcl-2 decreased significantly, and the apoptotic rate increased significantly. Nevertheless, when Sfrp5 expression was upregulated, the result was the opposite. SFRP5 and Wnt5a are involved in the vascular endothelial injury. Wnt5a can promote apoptosis of HUVEC cells through Wnt5a/JNK/Caveolin-1 pathway, while SFRP5 can inhibit apoptosis by interfering with this pathway.

Restricted access

Shubhashree Uppangala, Akshatha Daddangadi, Jeena Susan Joseph, Sujit Raj Salian, Riddhi Kirit Pandya, Guruprasad Kalthur, and Satish Kumar Adiga

Corticosteroids are increasingly being used during the peri-implantation period to treat women with repeated IVF failure and recurrent miscarriage. However, the direct effects of prednisolone (PRDL), one of the commonly used corticosteroids on early embryo development is not understood. To mimic the possible clinical scenario and to understand the embryonic response to direct PRDL exposure, this pilot study was conducted in a mouse model. Cleavage stage embryos exposed to 3 and 30µM PRDL in vitro were assessed for peri-implantation developmental potential, genetic integrity, inner cell mass (ICM) proliferation and pluripotency markers in the proliferated ICM cells. Exposure to 30µM PRDL delayed the embryonic progression beyond compaction (P<0.05) in comparison to vehicle control and, had reduced total cell number (P<0.001) than all other groups. In addition, 30µM PRDL exposure resulted in poor hatching potential (P<0.05) and increased apoptosis in blastocysts (P<0.05) compared to 3µM PRDL. On the other hand, completely formed ICM outgrowths were significantly higher (P<0.05) in 3µM PRDL compared to control. However, no significant differences were observed in the expression of pluripotency genes. In conclusion, the trend observed in embryos exposed to PRDL in vitro provides important information concerning the use of this drug when treating patients at the peri-implantation phase of IVF cycles. However, the clinical value of this observation on human embryo development needs further research.

Restricted access

Russell T Turner, Adam J Branscum, Carmen P Wong, Urszula T Iwaniec, and Emily Morey-Holton

The gravitostat is purported to function as a leptin-independent, osteocyte-dependent mechanism for regulation of energy balance. If correct, reduced activation of gravitostat signaling caused by prolonged sitting may contribute to obesity. The gravitostat concept is supported by reduced body mass in rodents following surgical implantation of weighted capsules. However, the procedure induces a confounding injury response. We, therefore, sought to confirm a gravitostat by decreasing (microgravity and simulated microgravity) or increasing (simulated gravity) weight using less invasive models (spaceflight, hindlimb unloading and centrifugation). We also evaluated changes in weight following non-surgical injury (radiation). Male rats (Wistar, Sprague–Dawley and Fischer 344) ranging in age from 5–12 weeks at launch and flown for 4–19 days in low Earth orbit exhibited slightly lower (4-day flight) or no difference (all other studies) in weight compared to ground controls. Rats subjected to inflight (1.0 G) or ground (1.04 G and 1.56 G) centrifugation during a 19-day mission did not differ in weight. In female rats (Fischer 344), spaceflight (14 days) did not alter ovariectomy-induced weight gain. Finally, hindlimb unloading resulted in weight loss in lean and obese mice. The aforementioned findings are inconsistent with outcomes predicted by a gravitostat namely increased mass during weightlessness and decreased mass when subjected to >1 G simulated gravity. Injury (dose-associated graded increases in radiation) mimicked the leptin-independent weight changes attributed to a gravitostat. Taken together, these findings do not support gravitostat regulation of energy balance and suggest injury/stress as an alternative mechanism for weight loss induced by weighted capsules.

Restricted access

Christine A. Cabelka, Cory W. Baumann, Angus Lindsay, Andrew Norton, Nick C. Blixt, Gengyun Le, Gordon L Warren, Kim C. Mansky, Susan A. Novotny, and Dawn A. Lowe

The actions of selective estrogen receptor modulators are tissue dependent. The primary objective of the current study was to determine the tissue selective effects of bazedoxifene (BZA) on the musculoskeletal system of ovariectomized (OVX) female mice, focusing on strengths of muscle-bone pairs in the lower hindlimb. Treatment with BZA after ovariectomy (OVX+BZA) did not prevent body or fat mass gains (p<0.05). In vivo plantarflexor muscle isometric torque was not affected by treatment with BZA (p=0.522). Soleus muscle peak isometric, concentric and eccentric tetanic force production were greater in OVX+BZA mice compared to OVX+E2 mice (p≤0.048) with no effect on maximal isometric specific force (p=0.228). Tibia from OVX+BZA mice had greater cortical cross-sectional area and moment of inertia than OVX mice treated with placebo (p<0.001), but there was no impact of BZA treatment on cortical bone mineral density, cortical thickness, tibial bone ultimate load or stiffness (p≥0.086). Overall, these results indicate that BZA may be an estrogen receptor agonist in skeletal muscle, as it has previously been shown in bone, providing minor benefits to the musculoskeletal system.