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Acute metformin induces hyperglycemia in healthy adult mourning doves, Zenaida macroura. Comp Biochem Physiol A Mol Integr Physiol 2024; 291:111594. [PMID: 38311294 DOI: 10.1016/j.cbpa.2024.111594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/10/2024]
Abstract
Birds have the highest blood glucose among vertebrates. Several mechanisms may explain this including the lack of a functional insulin-responsive glucose transport protein, high glucagon concentrations, and reliance on lipid oxidation resulting in the production of gluconeogenic precursors. The hypothesis was that interruption of gluconeogenesis using the diabetes medication metformin would lower glucose concentrations in wild-caught birds. We captured two cohorts of adult mourning doves, Zenaida macroura, and acclimated them to captivity for two weeks. In this crossover study, cohort 1 was administered a single dose of one of the following oral treatments each week: metformin (150 or 300 mg/kg), glycogenolysis inhibitor (2.5 mg/kg 1,4-dideoxy-1,4-imino-D-arabinitol (DAB)), or water (50 μL). Whole blood glucose was measured using a glucometer at baseline, 30, 60, and 120 min following the oral doses. In contrast to mammals and chickens, 300 mg/kg metformin did not alter blood glucose (p > 0.05) whereas 150 mg/kg metformin increased blood glucose compared to water (p = 0.043). To examine whether 150 mg/kg metformin stimulated glycogenolysis, we co-administered 150 mg/kg metformin and 2.5 mg/kg DAB, which prevented the hyperglycemic response. Cohort 2 was administered the same treatments and the early response was examined (0, 5, 10, 15 min). Low-dose metformin increased blood glucose within 5 min (p = 0.039) whereas the high dose had no effect. DAB did not prevent the early response to metformin nor did it alter blood glucose concentrations when administered alone (p = 0.887). In conclusion, metformin increases endogenous blood glucose via glycogenolysis in healthy adult male mourning doves.
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Adverse drug reactions on male fertility. Therapie 2024; 79:199-203. [PMID: 37973492 DOI: 10.1016/j.therap.2023.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 09/21/2023] [Indexed: 11/19/2023]
Abstract
For several years, fertility disorders have been on the increase worldwide. These disorders affect both sexes, but are more pronounced in men; and in half of cases the etiology is unknown. The role of drugs in male infertility has been little studied to date. Most of the available data comes from experimental animal studies, with all their limitations. With the exception of a few drugs, such as certain anticancer agents, human data are rare. This article describes the mainly drugs known to have deleterious effects on male fertility, the mechanisms leading to these effects and methods used to assess the risk of drug-induced male infertility. It underlines the need for further work in experimental research, clinical trials and post-marketing surveillance to improve our knowledge of drugs that induce male infertility. Although these adverse effects are not life-threatening, they can have a significant impact on patients' lives.
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Impact of endocrine disrupting chemicals and pharmaceuticals on Sertoli cell development and functions. Front Endocrinol (Lausanne) 2023; 14:1095894. [PMID: 36793282 PMCID: PMC9922725 DOI: 10.3389/fendo.2023.1095894] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/04/2023] [Indexed: 02/01/2023] Open
Abstract
Sertoli cells play essential roles in male reproduction, from supporting fetal testis development to nurturing male germ cells from fetal life to adulthood. Dysregulating Sertoli cell functions can have lifelong adverse effects by jeopardizing early processes such as testis organogenesis, and long-lasting processes such as spermatogenesis. Exposure to endocrine disrupting chemicals (EDCs) is recognized as contributing to the rising incidence of male reproductive disorders and decreasing sperm counts and quality in humans. Some drugs also act as endocrine disruptors by exerting off-target effects on endocrine tissues. However, the mechanisms of toxicity of these compounds on male reproduction at doses compatible with human exposure are still not fully resolved, especially in the case of mixtures, which remain understudied. This review presents first an overview of the mechanisms regulating Sertoli cell development, maintenance, and functions, and then surveys what is known on the impact of EDCs and drugs on immature Sertoli cells, including individual compounds and mixtures, and pinpointing at knowledge gaps. Performing more studies on the impact of mixtures of EDCs and drugs at all ages is crucial to fully understand the adverse outcomes these chemicals may induce on the reproductive system.
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17β-estradiol rescues the damage of thiazolidinedione on chicken Sertoli cell proliferation via adiponectin. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 233:113308. [PMID: 35176672 DOI: 10.1016/j.ecoenv.2022.113308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 01/26/2022] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
Thiazolidinedione (TZD) is an oral anti-diabetic drug that exhibits some side effects on the male reproductive system by interfering with the steroidogenesis and androgenic activity and also shows anti-proliferative effect on several cell types. This study investigated the effect of TZD on immature chicken Sertoli cell (SC) proliferation and the potential mechanism by which 17β-estradiol regulated this process. Chicken SC viability was investigated under different treatment concentration and time of TZD. 17β-estradiol (0.001 μM, 24 h) was added to analyze its effects on TZD-mediated cell viability, cell metabolic activity, cell growth, cell cycle progression, reactive oxygen species (ROS) level, antioxidant enzyme activity, mitochondria activity, oxygen consumption rate, adenosine triphosphate (ATP) level, and mitochondrial respiratory chain enzyme activity, adiponectin expression and several cell proliferation-related genes mRNA and protein levels. We performed the microRNA (miRNA) array to find TZD-induced differentially expressed miRNAs and validated whether miR-1577 can target on adiponectin via the dual luciferase reporter assay, as well as verified the effect of adiponectin addition with different concentrations on the SC viability. Further, SCs were transfected with miR-1577 agomir (a double-stranded synthetic miRNA mimic) in the presence or absence of TZD and antagomir (a single-stranded synthetic miRNA inhibitor) in the presence or absence of 17β-estradiol to analyze whether miR-1577 was involved in TZD-mediated SC proliferation and whether 17β-estradiol regulated this process. Results showed that TZD significantly inhibited SC viability, cell metabolic activity, cell growth, and cell cycle progression, while increased adiponectin level and ROS generation. TZD-treated SCs presented decreases of antioxidant enzyme activity, mitochondria activity, basal and maximal respiration, ATP production and level, mitochondrial respiratory chain enzyme activity, and mRNA and protein expressions of several cell proliferation-related genes, as well as the significant alteration of miRNA expressions (a total number of 55 miRNAs were up-regulated whereas 53 miRNAs down-regulated). Whereas, 17β-estradiol played a positive role in chicken SC proliferation and rescued the damage of TZD on SC proliferation by up-regulating miR-1577 expression whose target gene was validated to be the adiponectin. In addition, exogenous adiponectin (more than 1 μg/ml) treatment exhibited a significant inhibition on the SC viability. Transfection of miR-1577 agomir promoted the SC proliferation via down-expressed adiponectin, and increased the mitochondrial function and cell proliferation-related gene expression, while TZD weakened the positive effect of miR-1577 agomir on SCs. On the other hand, transfection of miR-1577 antagomir inhibited SC proliferation by producing the opposite effects on above parameters, while 17β-estradiol attenuated the negative effect of miR-1577 antagomir on SCs. These findings suggest down-expressed miR-1577 is involved in the regulation of TZD-inhibited SC proliferation through increasing adiponectin level, and this damage of TZD on the immature chicken SC proliferation can be ameliorated by appropriate dose of exogenous 17β-estradiol treatment. This study provides an insight into the cytoprotective effect of 17β-estradiol on TZD-damaged SC proliferation and may suggest a potential strategy for reducing the risk of SC dysfunction caused by the abuse of TZD.
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Effect of vitamin E supplementation on chicken sperm quality: A meta-analysis. Vet World 2022; 15:419-426. [PMID: 35400966 PMCID: PMC8980400 DOI: 10.14202/vetworld.2022.419-426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 01/18/2022] [Indexed: 11/19/2022] Open
Abstract
Background and Aim: Among several factors, the sperm quality of poultry is affected by the rooster’s body size and the availability of antioxidants like vitamin E. This study aimed to determine the effect of dietary vitamin E supplementation on rooster sperm quality through a meta-analysis. Materials and Methods: After verification and evaluation, a total of 19 articles were included in this study. Data, including dietary vitamin E, semen volume, concentration, total sperm cells, pH, motility, viability, percentage of dead and abnormal sperm, vitamin E sperm content, malondialdehyde (MDA) content, and testosterone levels, were tabulated in a database; these were subsequently analyzed using mixed modeling with vitamin E dose as a fixed effect and study identity as a random effect. Results: Dietary supplementation level of vitamin E significantly (p<0.001) affected sperm concentration, significantly affected motility (p<0.001), significantly affected sperm vitamin E (p<0.001), significantly affected viability (p<0.001), and significantly affected chicken sperm fertility (p=0.001). Vitamin E administration also significantly reduced the number of sperm cell deaths (p<0.001); however, increased dietary levels of vitamin E did not affect semen volume (p=0.853), pH (p=0.951), MDA (p=0.542), the percentage of abnormal sperm cells (p=0.343), nor testosterone levels (p=0.063). Conclusion: Dietary vitamin E supplementation is recommended for male chickens since it generally enhances the quality of their sperm.
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In Utero Exposure to Metformin Reduces the Fertility of Male Offspring in Adulthood. Front Endocrinol (Lausanne) 2021; 12:750145. [PMID: 34745014 PMCID: PMC8565088 DOI: 10.3389/fendo.2021.750145] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/17/2021] [Indexed: 12/11/2022] Open
Abstract
Metformin is a drug used for the treatment of type 2 diabetes and disorders associated with insulin resistance. Metformin is also used in the treatment of pregnancy disorders such as gestational diabetes. However, the consequences of foetal exposure to metformin on the fertility of exposed offspring remain poorly documented. In this study, we investigated the effect of in utero metformin exposure on the fertility of female and male offspring. We observed that metformin is detectable in the blood of the mother and in amniotic fluid and blood of the umbilical cord. Metformin was not measurable in any tissues of the embryo, including the gonads. The effect of metformin exposure on offspring was sex specific. The adult females that had been exposed to metformin in utero presented no clear reduction in fertility. However, the adult males that had been exposed to metformin during foetal life exhibited a 30% reduction in litter size compared with controls. The lower fertility was not due to a change in sperm production or the motility of sperm. Rather, the phenotype was due to lower sperm head quality - significantly increased spermatozoa head abnormality with greater DNA damage - and hypermethylation of the genomic DNA in the spermatozoa associated with lower expression of the ten-eleven translocation methylcytosine dioxygenase 1 (TET1) protein. In conclusion, while foetal metformin exposure did not dramatically alter gonad development, these results suggest that metabolic modification by metformin during the foetal period could change the expression of epigenetic regulators such as Tet1 and perturb the genomic DNA in germ cells, changes that might contribute to a reduced fertility.
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Estradiol ameliorates metformin-inhibited Sertoli cell proliferation via AMPK/TSC2/mTOR signaling pathway. Theriogenology 2021; 175:7-22. [PMID: 34481229 DOI: 10.1016/j.theriogenology.2021.08.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/31/2021] [Accepted: 08/25/2021] [Indexed: 12/15/2022]
Abstract
Metformin is a commonly used for treating type 2 diabetes and it acts on a variety of organs including the male reproductive system. 17β-estradiol plays an important role in Sertoli cell (SC) proliferation which determines the germ cell development and spermatogenesis. The aim of this study is to investigate the effect of metformin on immature chicken SC proliferation and the potential mechanisms by which 17β-estradiol regulate this process. Results showed that metformin significantly inhibited SC proliferation, whereas 17β-estradiol weakened the inhibitory effects of metformin on SC viability, cell growth, and cell cycle progression. SC proliferation-inhibiting effect of metformin exposure was regulated by decreasing adenosine triphosphate level and respiratory enzyme activity in the mitochondria; this process was possibly mediated by the adenosine monophosphate-activated protein kinase (AMPK)/tuberous sclerosis complex 2 (TSC2)/mammalian target of rapamycin (mTOR) signaling pathway, which was regulated by the down-expressed miR-1764 and by the decreased antioxidant enzyme activity and excessive reactive oxygen species generation. In addition, SCs transfected with the miR-1764 agomir led to an improvement of proliferation capacity through down-regulating AMPKα2 level, which further decreased TSC2 expression and induced mTOR activation. However, the anti-proliferative effect of miR-1764 antagomir can be alleviated by 17β-estradiol treatment via the up-expression of miR-1764 in transfected SCs. Our findings suggest appropriate dose of exogenous 17β-estradiol treatment can ameliorate the inhibitory effect of metformin on SC proliferation via the regulation of AMPK/TSC2/mTOR signaling pathway, this might reduce the risk of poor male fertility caused by the abuse of anti-diabetic agents.
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Postnatal metformin treatment alters rat Sertoli cell proliferation and daily sperm production. Andrology 2021; 9:965-976. [PMID: 33305512 DOI: 10.1111/andr.12957] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND The direct correlation between Sertoli cell number and sperm production capacity highlights the importance of deciphering external factors that modify Sertoli cell proliferation. A growing body of evidence in vitro suggests that metformin, the main pharmacological agent for type 2 diabetes treatment in children, exerts anti-proliferative effects on Sertoli cells. OBJECTIVE The aims of this study were to investigate the effect of metformin administration during postnatal period on Sertoli cell proliferation and on cell cycle regulators expression and to analyze the impact of this treatment on the sperm production capacity in adulthood. MATERIALS AND METHODS Sprague Dawley rat pups were randomly divided into two groups: MET (receiving daily 200 mg/kg metformin, from Pnd3 to Pnd7 inclusive) and control (receiving vehicle). BrdU incorporation was measured to assess proliferation. Gene expression analyses were performed in Sertoli cells isolated from animals of both groups. Daily sperm production and sperm parameters were measured in adult male rats (Pnd90) that received neonatal treatment. RESULTS MET group exhibited a significant decrease in BrdU incorporation in Sertoli cells. Concordantly, MET group showed a reduction in cyclin D1 and E2 expression and an increase in p21 expression in Sertoli cells. In addition, metformin-treated animals displayed lower values of daily sperm production on Pnd90. DISCUSSION AND CONCLUSION These results suggest that metformin treatment may lead to a decrease in Sertoli cell proliferation, a concomitant altered expression of cell cycle regulators and ultimately, a reduction in daily sperm production in adult animals.
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Progress and challenges in developing organoids in farm animal species for the study of reproduction and their applications to reproductive biotechnologies. Vet Res 2021; 52:42. [PMID: 33691745 PMCID: PMC7944619 DOI: 10.1186/s13567-020-00891-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/29/2020] [Indexed: 02/06/2023] Open
Abstract
Within the past decades, major progress has been accomplished in isolating germ/stem/pluripotent cells, in refining culture medium and conditions and in establishing 3-dimensional culture systems, towards developing organoids for organs involved in reproduction in mice and to some extent in humans. Haploid male germ cells were generated in vitro from primordial germ cells. So were oocytes, with additional support from ovarian cells and subsequent follicle culture. Going on with the female reproductive tract, spherical oviduct organoids were obtained from adult stem/progenitor cells. Multicellular endometrial structures mimicking functional uterine glands were derived from endometrial cells. Trophoblastic stem cells were induced to form 3-dimensional syncytial-like structures and exhibited invasive properties, a crucial point for placentation. Finally, considering the embryo itself, pluripotent embryonic cells together with additional extra-embryonic cells, could self-organize into a blastoid, and eventually into a post-implantation-like embryo. Most of these accomplishments have yet to be reached in farm animals, but much effort is devoted towards this goal. Here, we review the progress and discuss the specific challenges of developing organoids for the study of reproductive biology in these species. We consider the use of such organoids in basic research to delineate the physiological mechanisms involved at each step of the reproductive process, or to understand how they are altered by environmental factors relevant to animal breeding. We evaluate their potential in reproduction of animals with a high genetic value, from a breeding point of view or in the context of preserving local breeds with limited headcounts.
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Effect of Metformin on Testosterone Levels in Male Patients With Type 2 Diabetes Mellitus Treated With Insulin. Front Endocrinol (Lausanne) 2021; 12:813067. [PMID: 35002984 PMCID: PMC8740051 DOI: 10.3389/fendo.2021.813067] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 12/08/2021] [Indexed: 12/29/2022] Open
Abstract
AIM To explore the chronic effects of metformin on testosterone levels in men with type 2 diabetes mellitus (T2DM). METHODS This is a secondary analysis of a real-world study evaluating the efficacy and safety of premixed insulin treatment in patients with T2DM via 3-month intermittent flash glucose monitoring. Male patients aged 18-60 who were using metformin during the 3-month study period were included as the metformin group. The control group included males without metformin therapy by propensity score matching analysis with age as a covariate. Testosterone levels were measured at baseline and after 3-month treatment. RESULTS After 3-month treatment, the control group had higher levels of total testosterone, free and bioavailable testosterone than those at baseline (P<0.05). Compared with the control group, the change of total (-0.82 ± 0.59 vs. 0.99 ± 0.59 nmol/L) and bioavailable (-0.13 ± 0.16 vs. 0.36 ± 0.16 nmol/L) testosterone levels in the metformin group significantly decreased (P=0.036 and 0.029, respectively). In Glycated Albumin (GA) improved subgroup, the TT, FT, and Bio-T levels in the control subgroup were higher than their baseline levels (P < 0.05). Compared with the metformin subgroup, TT level in the control subgroup also increased significantly (P=0.044). In GA unimproved subgroup, the change of TT level in the metformin subgroup was significantly lower than that in the control subgroup (P=0.040). CONCLUSION In men with T2DM, 3-month metformin therapy can reduce testosterone levels, and counteract the testosterone elevation that accompanied with the improvement of blood glucose. CLINICAL TRIAL REGISTRATION https://www.clinicaltrials.gov/ct2/show/NCT04847219?term=04847219&draw=2&rank=1.
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Mechanical Stimulation: A Crucial Element of Organ-on-Chip Models. Front Bioeng Biotechnol 2020; 8:602646. [PMID: 33363131 PMCID: PMC7758201 DOI: 10.3389/fbioe.2020.602646] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/20/2020] [Indexed: 12/13/2022] Open
Abstract
Organ-on-chip (OOC) systems recapitulate key biological processes and responses in vitro exhibited by cells, tissues, and organs in vivo. Accordingly, these models of both health and disease hold great promise for improving fundamental research, drug development, personalized medicine, and testing of pharmaceuticals, food substances, pollutants etc. Cells within the body are exposed to biomechanical stimuli, the nature of which is tissue specific and may change with disease or injury. These biomechanical stimuli regulate cell behavior and can amplify, annul, or even reverse the response to a given biochemical cue or drug candidate. As such, the application of an appropriate physiological or pathological biomechanical environment is essential for the successful recapitulation of in vivo behavior in OOC models. Here we review the current range of commercially available OOC platforms which incorporate active biomechanical stimulation. We highlight recent findings demonstrating the importance of including mechanical stimuli in models used for drug development and outline emerging factors which regulate the cellular response to the biomechanical environment. We explore the incorporation of mechanical stimuli in different organ models and identify areas where further research and development is required. Challenges associated with the integration of mechanics alongside other OOC requirements including scaling to increase throughput and diagnostic imaging are discussed. In summary, compelling evidence demonstrates that the incorporation of biomechanical stimuli in these OOC or microphysiological systems is key to fully replicating in vivo physiology in health and disease.
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Roles of AMP-Activated Protein Kinase (AMPK) in Mammalian Reproduction. Front Cell Dev Biol 2020; 8:593005. [PMID: 33330475 PMCID: PMC7710906 DOI: 10.3389/fcell.2020.593005] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 10/23/2020] [Indexed: 12/01/2022] Open
Abstract
Reproduction is an energy demanding function and only take place in case of sufficient available energy status in mammals. Metabolic diseases such as anorexia nervosa are clinically associated with reduced fertility. AMP-activated protein kinase (AMPK), as a major regulator of cellular energy homeostasis, is activated in limited energy reserves to ensure the orderly progress of various physiological activities. In recent years, mounting evidence shows that AMPK is involved in the regulation of reproductive function through multiple mechanisms. AMPK is likely to be a metabolic sensor integrating central and peripheral signals. In this review, we aim to explore the preclinical studies published in the last decade that investigate the role of AMP-activated protein kinase in the reproductive field, and its role as a target for drug therapy of reproductive system-related diseases. We also emphasized the emerging roles of AMPK in transcriptional regulation of reproduction processes and metabolisms, which are tightly related to the energy state and fertility of an organism.
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Effects of Insulin on Porcine Neonatal Sertoli Cell Responsiveness to FSH In Vitro. J Clin Med 2019; 8:jcm8060809. [PMID: 31174276 PMCID: PMC6617126 DOI: 10.3390/jcm8060809] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 05/29/2019] [Accepted: 06/03/2019] [Indexed: 12/30/2022] Open
Abstract
There is ongoing debate as to whether the decline of sperm production in recent times may be related to a parallel increase in the rate of obesity and diabetes. Lower anti-Müllerian hormone (AMH) and inhibin B secretion have been observed in young hyperinsulinemic patients compared to healthy controls, suggesting a Sertoli cell (SC) dysfunction. The pathophysiological mechanisms underlying SC dysfunction in these patients are poorly understood. To the best of our knowledge, no evidence is available on the effects of insulin on SC function. Therefore, this study was undertaken to assess the effects of insulin on basal and follicle-stimulating hormone (FSH)-stimulated SC function in vitro. To accomplish this, we evaluated the expression of AMH, inhibin B and FSHR genes, the secretion of AMH and inhibin B and the phosphorylation of AKT473 and SC proliferation on neonatal porcine SC after incubation with FSH and/or insulin. We found that similar to FSH, the expression and secretion of AMH is suppressed by insulin. Co-incubation with FSH and insulin decreased AMH secretion significantly more than with FSH alone. Insulin had no effect on the expression and secretion of the inhibin B gene, but co-incubation with FSH and insulin had a lower effect on inhibin B secretion than that found with FSH alone. FSH and/or insulin increased AKT473 phosphorylation and SC proliferation. In conclusion, the results of this study showed that insulin modulates SC function. We hypothesize that hyperinsulinemia may therefore influence testicular function even before puberty begins. Therefore, particular care should be taken to avoid the onset of hyperinsulinemia in children to prevent a future deleterious effect on fertility.
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Molecular Mechanisms and Signaling Pathways Involved in Sertoli Cell Proliferation. Front Endocrinol (Lausanne) 2019; 10:224. [PMID: 31040821 PMCID: PMC6476933 DOI: 10.3389/fendo.2019.00224] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 03/21/2019] [Indexed: 12/16/2022] Open
Abstract
Sertoli cells are somatic cells present in seminiferous tubules which have essential roles in regulating spermatogenesis. Considering that each Sertoli cell is able to support a limited number of germ cells, the final number of Sertoli cells reached during the proliferative period determines sperm production capacity. Only immature Sertoli cells, which have not established the blood-testis barrier, proliferate. A number of hormonal cues regulate Sertoli cell proliferation. Among them, FSH, the insulin family of growth factors, activin, and cytokines action must be highlighted. It has been demonstrated that cAMP/PKA, ERK1/2, PI3K/Akt, and mTORC1/p70SK6 pathways are the main signal transduction pathways involved in Sertoli cell proliferation. Additionally, c-Myc and hypoxia inducible factor are transcription factors which participate in the induction by FSH of various genes of relevance in cell cycle progression. Cessation of proliferation is a pre-requisite to Sertoli cell maturation accompanied by the establishment of the blood-testis barrier. With respect to this barrier, the participation of androgens, estrogens, thyroid hormones, retinoic acid and opioids has been reported. Additionally, two central enzymes that are involved in sensing cell energy status have been associated with the suppression of Sertoli cell proliferation, namely AMPK and Sirtuin 1 (SIRT1). Among the molecular mechanisms involved in the cessation of proliferation and in the maturation of Sertoli cells, it is worth mentioning the up-regulation of the cell cycle inhibitors p21Cip1, p27Kip, and p19INK4, and of the gap junction protein connexin 43. A decrease in Sertoli cell proliferation due to administration of certain therapeutic drugs and exposure to xenobiotic agents before puberty has been experimentally demonstrated. This review focuses on the hormones, locally produced factors, signal transduction pathways, and molecular mechanisms controlling Sertoli cell proliferation and maturation. The comprehension of how the final number of Sertoli cells in adulthood is established constitutes a pre-requisite to understand the underlying causes responsible for the progressive decrease in sperm production that has been observed during the last 50 years in humans.
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Abstract
Initially produced in Europe in 1958, metformin is still one of the most widely prescribed drugs to treat type II diabetes and other comorbidities associated with insulin resistance. Metformin has been shown to improve fertility outcomes in females with insulin resistance associated with polycystic ovary syndrome (PCOS) and in obese males with reduced fertility. Metformin treatment reinstates menstrual cyclicity, decreases the incidence of cesareans, and limits the number of premature births. Notably, metformin reduces steroid levels in conditions associated with hyperandrogenism (e.g., PCOS and precocious puberty) in females and improves fertility of adult men with metabolic syndrome through increased testosterone production. While the therapeutical use of metformin is considered to be safe, in the last 10 years some epidemiological studies have described phenotypic differences after prenatal exposure to metformin. The goals of this review are to briefly summarize the current knowledge on metformin focusing on its effects on the female and male reproductive organs, safety concerns, including the potential for modulating fetal imprinting via epigenetics.
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AMPK Function in Mammalian Spermatozoa. Int J Mol Sci 2018; 19:ijms19113293. [PMID: 30360525 PMCID: PMC6275045 DOI: 10.3390/ijms19113293] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 10/16/2018] [Accepted: 10/20/2018] [Indexed: 01/03/2023] Open
Abstract
AMP-activated protein kinase AMPK regulates cellular energy by controlling metabolism through the inhibition of anabolic pathways and the simultaneous stimulation of catabolic pathways. Given its central regulator role in cell metabolism, AMPK activity and its regulation have been the focus of relevant investigations, although only a few studies have focused on the AMPK function in the control of spermatozoa's ability to fertilize. This review summarizes the known cellular roles of AMPK that have been identified in mammalian spermatozoa. The involvement of AMPK activity is described in terms of the main physiological functions of mature spermatozoa, particularly in the regulation of suitable sperm motility adapted to the fluctuating extracellular medium, maintenance of the integrity of sperm membranes, and the mitochondrial membrane potential. In addition, the intracellular signaling pathways leading to AMPK activation in mammalian spermatozoa are reviewed. We also discuss the role of AMPK in assisted reproduction techniques, particularly during semen cryopreservation and preservation (at 17 °C). Finally, we reinforce the idea of AMPK as a key signaling kinase in spermatozoa that acts as an essential linker/bridge between metabolism energy and sperm's ability to fertilize.
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Metformin counteracts the effects of FSH on rat Sertoli cell proliferation. Reproduction 2018; 156:93-101. [DOI: 10.1530/rep-18-0233] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 05/21/2018] [Indexed: 12/16/2022]
Abstract
Metformin (MET) is one of the most widely used anti-hyperglycemic agents for treating patients with type 2 diabetes and it has started to be used in pediatric population at ages when Sertoli cells are still proliferating. It is well known that follicle-stimulating hormone (FSH) is the major Sertoli cell mitogen. The aim of the study is to investigate a possible effect of MET, which has been shown to have anti-proliferative properties, on FSH regulation of postnatal Sertoli cell proliferation and on the molecular mechanisms involved in this regulation. The present study was performed in eight-day-old rat Sertoli cell cultures. The results obtained show that MET in the presence of FSH increases phosphorylated acetyl-CoA carboxylase and decreases phosphorylated p70S6K levels. Moreover, we show that MET decreases FSH-stimulated Sertoli cell proliferation, and this decrease is accompanied by a reduction in FSH-stimulated Ccnd1 and Ccnd2 expression and an increase in cell cycle inhibitor p21Cip expression. Altogether, these results suggest that MET can, at least in part, counteract the effect of FSH on postnatal Sertoli cell proliferation.
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Differential proliferation and metabolic activity of Sertoli cells in the testes of broiler and layer breeder chickens. Poult Sci 2017; 96:2459-2470. [DOI: 10.3382/ps/pex025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Indexed: 12/17/2022] Open
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Impact of 5'-amp-activated Protein Kinase on Male Gonad and Spermatozoa Functions. Front Cell Dev Biol 2017; 5:25. [PMID: 28386541 PMCID: PMC5362614 DOI: 10.3389/fcell.2017.00025] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/07/2017] [Indexed: 12/12/2022] Open
Abstract
As we already know, the male reproductive system requires less energetic investment than the female one. Nevertheless, energy balance is an important feature for spermatozoa production in the testis and for spermatozoa properties after ejaculation. The 5'-AMP-activated protein kinase, AMPK, is a sensor of cell energy, that regulates many metabolic pathways and that has been recently shown to control spermatozoa quality and functions. It is indeed involved in the regulation of spermatozoa quality through its action on the proliferation of testicular somatic cells (Sertoli and Leydig), on spermatozoa motility and acrosome reaction. It also favors spermatozoa quality through the management of lipid peroxidation and antioxidant enzymes. I review here the most recent data available on the roles of AMPK in vertebrate spermatozoa functions.
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