Endocrine Disruptors and Metabolic Changes: Impact on Puberty Control

OBJECTIVE

This study aims to explore the significant impact of environmental chemicals on disease development, focusing on their role in developing metabolic and endocrine diseases. The objective is to understand how these chemicals contribute to the increasing prevalence of precocious puberty, considering various factors, including epigenetic changes, lifestyle, and emotional disturbances.

METHODS

The study employs a comprehensive review of descriptive observational studies in both human and animal models to identify a degree of causality between exposure to environmental chemicals and disease development, specifically focusing on endocrine disruption. Due to ethical constraints, direct causation studies in human subjects are not feasible; therefore, the research relies on accumulated observational data.

RESULTS

Puberty is a crucial life period with marked physiological and psychological changes. The age at which sexual characteristics develop is changing in many regions. The findings indicate a correlation between exposure to endocrine-disrupting chemicals and the early onset of puberty. These chemicals have been shown to interfere with normal hormonal processes, particularly during critical developmental stages such as adolescence. The research also highlights the interaction of these chemical exposures with other factors, including nutritional history, social and lifestyle changes, and emotional stress, which together contribute to the prevalence of precocious puberty.

CONCLUSION

Environmental chemicals significantly contribute to the development of certain metabolic and endocrine diseases, particularly in the rising incidence of precocious puberty. Although the evidence is mainly observational, it adequately justifies regulatory actions to reduce exposure risks. Furthermore, these findings highlight the urgent need for more research on the epigenetic effects of these chemicals and their wider impact on human health, especially during vital developmental periods.

Molecular perspectives in hypertrophic heart disease: An epigenetic approach from chromatin modification

Epigenetic changes induced by environmental factors are increasingly relevant in cardiovascular diseases. The most frequent molecular component in cardiac hypertrophy is the reactivation of fetal genes caused by various pathologies, including obesity, arterial hypertension, aortic valve stenosis, and congenital causes. Despite the multiple investigations performed to achieve information about the molecular components of this pathology, its influence on therapeutic strategies is relatively scarce. Recently, new information has been taken about the proteins that modify the expression of fetal genes reactivated in cardiac hypertrophy. These proteins modify the DNA covalently and induce changes in the structure of chromatin. The relationship between histones and DNA has a recognized control in the expression of genes conditioned by the environment and induces epigenetic variations. The epigenetic modifications that regulate pathological cardiac hypertrophy are performed through changes in genomic stability, chromatin architecture, and gene expression. Histone 3 trimethylation at lysine 4, 9, or 27 (H3-K4; -K9; -K27me3) and histone demethylation at lysine 9 and 79 (H3-K9; -K79) are mediators of reprogramming in pathologic hypertrophy. Within the chromatin architecture modifiers, histone demethylases are a group of proteins that have been shown to play an essential role in cardiac cell differentiation and may also be components in the development of cardiac hypertrophy. In the present work, we review the current knowledge about the influence of epigenetic modifications in the expression of genes involved in cardiac hypertrophy and its possible therapeutic approach.

Roles of estrogens, estrogen-like compounds, and endocrine disruptors in adipocytes

Women are subject to constitutional changes after menopause, which increases conditions and diseases prone to cardiovascular risks such as obesity and diabetes mellitus. Both estrogens and androgens influence the individual's metabolic mechanism, which controls the fat distribution and the hypothalamic organization of the regulatory centers of hunger and satiety. While androgens tend to accumulate fat in the splanchnic and the visceral region with an increase in cardiovascular risk, estrogens generate more subcutaneous and extremity distribution of adipose tissue. The absence of estrogen during menopause seems to be the main factor that gives rise to the greater predisposition of women to suffer cardiovascular alterations. However, the mechanisms by which estrogens regulate the energy condition of people are not recognized. Estrogens have several mechanisms of action, which mainly include the modification of specific receptors that belong to the steroid receptor superfamily. The alpha estrogen receptors (ERα) and the beta receptors (ERβ) have a fundamental role in the metabolic control of the individual, with a very characteristic corporal distribution that exerts an influence on the metabolism of lipids and glucose. Despite the significant amount of knowledge in this field, many of the regulatory mechanisms exerted by estrogens and ER continue to be clarified. This review will discuss the role of estrogens and their receptors on the central regulation of caloric expenditure and the influence they exert on the differentiation and function of adipocytes. Furthermore, chemical substances with a hormonal activity that cause endocrine disruption with affectation on estrogen receptors will be considered. Finally, the different medical therapies for the vasomotor manifestations of menopause and their role in reducing obesity, diabetes, and cardiovascular risk will be analyzed.

The Roles of Dietary, Nutritional and Lifestyle Interventions in Adipose Tissue Adaptation and Obesity

The obesity and the associated non-communicable diseases (NCDs) are globally increasing in their prevalence. While the modern-day lifestyle required less ventilation of metabolic energy through muscular activities, this lifestyle transition also provided the unlimited accession to foods around the clock, which prolong the daily eating period of foods that contained high calorie and high glycemic load. These situations promote the high continuous flux of carbon substrate availability in mitochondria and induce the indecisive bioenergetic switches. The disrupted bioenergetic milieu increases the uncoupling respiration due to the excess flow of the substrate-derived reducing equivalents and reduces ubiquinones into the respiratory chain. The diversion of the uncoupling proton gradient through adipocyte thermogenesis will then alleviate the damaging effects of free radicals to mitochondria and other organelles. The adaptive induction of white adipose tissues (WAT) to beige adipose tissues (beAT) has shown beneficial effects on glucose oxidation, ROS protection and mitochondrial function preservation through the uncoupling protein 1 (UCP1)-independent thermogenesis of beAT. However, the maladaptive stage can eventually initiate with the persistent unhealthy lifestyles. Under this metabolic gridlock, the low oxygen and pro-inflammatory environments promote the adipose breakdown with sequential metabolic dysregulation, including insulin resistance, systemic inflammation and clinical NCDs progression. It is unlikely that a single intervention can reverse all these complex interactions. A comprehensive protocol that includes dietary, nutritional and all modifiable lifestyle interventions, can be the preferable choice to decelerate, stop, or reverse the NCDs pathophysiologic processes.

Control of Adipose Cell Browning and Its Therapeutic Potential

Adipose tissue is the largest endocrine organ in humans and has an important influence on many physiological processes throughout life. An increasing number of studies have described the different phenotypic characteristics of fat cells in adults. Perhaps one of the most important properties of fat cells is their ability to adapt to different environmental and nutritional conditions. Hypothalamic neural circuits receive peripheral signals from temperature, physical activity or nutrients and stimulate the metabolism of white fat cells. During this process, changes in lipid inclusion occur, and the number of mitochondria increases, giving these cells functional properties similar to those of brown fat cells. Recently, beige fat cells have been studied for their potential role in the regulation of obesity and insulin resistance. In this context, it is important to understand the embryonic origin of beige adipocytes, the response of adipocyte to environmental changes or modifications within the body and their ability to transdifferentiate to elucidate the roles of these cells for their potential use in therapeutic strategies for obesity and metabolic diseases. In this review, we discuss the origins of the different fat cells and the possible therapeutic properties of beige fat cells.

Diabetes Mellitus Is a Chronic Disease that Can Benefit from Therapy with Induced Pluripotent Stem Cells

Diabetes mellitus (DM) is one of the main causes of morbidity and mortality, with an increasing incidence worldwide. The impact of DM on public health in developing countries has triggered alarm due to the exaggerated costs of the treatment and monitoring of patients with this disease. Considerable efforts have been made to try to prevent the onset and reduce the complications of DM. However, because insulin-producing pancreatic β-cells progressively deteriorate, many people must receive insulin through subcutaneous injection. Additionally, current therapies do not have consistent results regarding the prevention of chronic complications. Leveraging the approval of real-time continuous glucose monitors and sophisticated algorithms that partially automate insulin infusion pumps has improved glycemic control, decreasing the burden of diabetes management. However, these advances are facing physiologic barriers. New findings in molecular and cellular biology have produced an extraordinary advancement in tissue development for the treatment of DM. Obtaining pancreatic β-cells from somatic cells is a great resource that currently exists for patients with DM. Although this therapeutic option has great prospects for patients, some challenges remain for this therapeutic plan to be used clinically. The purpose of this review is to describe the new techniques in cell biology and regenerative medicine as possible treatments for DM. In particular, this review highlights the origin of induced pluripotent cells (iPSCs) and how they have begun to emerge as a regenerative treatment that may mitigate the pathology of this disease.

Maturity-onset diabetes of the young type 5 a MULTISYSTEMIC disease: a CASE report of a novel mutation in the HNF1B gene and literature review

Background

Diabetes mellitus with autosomal dominant inheritance, such as maturity-onset diabetes of the young (MODY), is a genetic form of diabetes mellitus. MODY is a type of monogenic diabetes mellitus in which multiple genetic variants may cause an alteration to the functioning of beta cells. The three most known forms of MODY are caused by modifications to the hnf4a, gck, and hnf1a genes. However, other MODY variants can cause multiple alterations in the embryonic development of the endoderm. This is the case in patients presenting with MODY5, who have a mutation of the hepatic nuclear factor 1B (hnf1b) gene.

Case presentation

We present the clinical case of a 15 year-old patient with a family history of diabetes mellitus and a classical MODY type 5 (MODY5) phenotype involving the pancreas and kidney, with a novel, unreported mutation in the hnf1b gene.

Conclusions

MODY5 is characterised by a mutation in the hnf1b gene, which plays an important role in the development and function of multiple organs. It should be suspected in patients with unusual diabetes and multisystem involvement unrelated to diabetes.

Graphical abstract

SUN-141 Altitude as the Second Hit on the Appearance of Paragangliomas

Paragangliomas are rare neuroendocrine tumors with a high degree of inheritance. These neoplasms arise from the extra-adrenal autonomic paraganglion and can secrete catecholamines. Many patients debut with symptoms of hypertensive crisis, tachycardia, dyspnea, headache and intense sweating. However, many tumors that are derived from the parasympathetic system are asymptomatic. Supported on the genetic basis are classified into two conglomerates: conglomerate I are those that have mutations and alter the response to hypoxia. Cluster II has a more syndromatic component, with alteration in the function of complex signaling pathways. A study based on histopathological diagnoses was carried out between 2007 and 2017 at a hospital in Bogotá (Colombia) 2600 meters above sea level, which documented 108 cases of paragangliomas that were predominantly located at the carotid level (76%), with a 4.7:1 ratio between women and men. 93.2% of the patients came from geographical locations with heights above 2,500m above sea level. Most of the tumors were asymptomatic. We draw attention to the fact that paragangliomas are probably more frequent than clinically diagnosed and the influence of the environment on the development of these tumors is highlighted, with a special contribution of oxygen pressure as a second event that contributes to the formation of the tumor.

Obesidad: un problema en la atención de Covid-19

Actualmente el mundo atraviesa una de las peores crisis a nivel salud secundario a la infección por un nuevo coronavirus de alta transmisibilidad y mortalidad, que ha impactado múltiples aspectos. Se ha establecido de forma general que la severidad de la infección está asociada con edad avanzada y comorbilidades como hipertensión y diabetes. Por otro lado, la obesidad en este momento representa una de las mayores amenazas del sector salud, por su gran relación con morbimortalidad a nivel cardiometabólico, esto conlleva a un alto costo de la enfermedad. Este artículo busca alertar sobre lo que han llamado algunos expertos el “choque de dos pandemias”, esto dado al aumento de la prevalencia de obesidad a nivel mundial, donde  nuestro país no está exento, que podría relacionarse con un número mayor de personas vulnerables a la infección por COVID-19 y sus complicaciones respiratorias y de esta manera evitar desenlaces catastróficos.

EID1 suppresses lipid accumulation by inhibiting the expression of GPDH in 3T3-L1 preadipocytes

The imbalance between food intake and energy expenditure causes high accumulation of triglycerides in adipocytes. Obesity is related with the increased lipid accumulation in white adipose tissue, which is a major risk factor for the development of metabolic disorders, such as type 2 diabetes and cardiovascular disease. This study highlights the role of E1A-like inhibitor of differentiation 1 (EID1) in the modulation of adipogenesis through the downregulation of glycerol-3-phosphate dehydrogenase (GPDH), which is a key enzyme in the synthesis of triglycerides and is considered to be a marker of adipogenesis. By analyzing DNA microarray data, we found that when EID1 is overexpressed in preadipocytes (3T3-L1 cells) during adipocyte differentiation, EID1 inhibits lipid accumulation through the downregulation of GPDH. In contrast, EID1 is not involved in the regulation of intracellular glucose via the translocation of glucose transporter. A confocal image analysis showed that EID1 is located in the nucleus of preadipocytes in the form of speckles, which could be involved as a regulator of the transcriptional process. We further confirmed that EID1 is able to bind to the promoter sequence of GPDH in the nucleus. These findings provide a molecular explanation for the inhibitory effect of EID1 on lipid accumulation in adipocytes.

The Beige Adipocyte as a Therapy for Metabolic Diseases

Adipose tissue is traditionally categorized into white and brown relating to their function and morphology. The classical white adipose tissue builds up energy in the form of triglycerides and is useful for preventing fatigue during periods of low caloric intake and the brown adipose tissue more energetically active, with a greater number of mitochondria and energy production in the form of heat. Since adult humans possess significant amounts of active brown fat depots and its mass inversely correlates with adiposity, brown fat might play an important role in human obesity and energy homeostasis. New evidence suggests two types of thermogenic adipocytes with distinct developmental and anatomical features: classical brown adipocytes and beige adipocytes. Beige adipocyte has recently attracted special interest because of its ability to dissipate energy and the possible ability to differentiate themselves from white adipocytes. The presence of brown and beige adipocyte in human adults has acquired attention as a possible therapeutic intervention for metabolic diseases. Importantly, adult human brown appears to be mainly composed of beige-like adipocytes, making this cell type an attractive therapeutic target for obesity and obesity-related diseases, such as atherosclerosis, arterial hypertension and diabetes mellitus type 2. Because many epigenetics changes can affect beige adipocyte differentiation from adipose progenitor cells, the knowledge of the circumstances that affect the development of beige adipocyte cells may be important to new pathways in the treatment of metabolic diseases. New molecules have emerged as possible therapeutic targets, which through the impulse to develop beige adipocytes can be useful for clinical studies. In this review will discuss some recent observations arising from the unique physiological capacity of these cells and their possible role as ways to treat obesity and diabetes mellitus type 2.

Kdm4c is Recruited to Mitotic Chromosomes and Is Relevant for Chromosomal Stability, Cell Migration and Invasion of Triple Negative Breast Cancer Cells

Members of the jumonji-containing lysine demethylase protein family have been associated with cancer development, although their specific roles in the evolution of tumor cells remain unknown. This work examines the effects of lysine demethylase 4C (KDM4C) knockdown on the behavior of a triple-negative breast cancer cell line. KDM4C expression was knocked-down by siRNA and analyzed by Western blot and immunofluorescence. HCC38 cell proliferation was examined by MTT assay, while breast cancer cells’ migration and invasion were tested in Transwell format by chemotaxis. Immunofluorescence assays showed that KDM4C, which is a key protein for modulating histone demethylation and chromosome stability through the distribution of genetic information, is located at the chromosomes during mitosis. Proliferation assays demonstrated that KDM4C is important for cell survival, while Transwell migration and invasion assays indicated that this protein is relevant for cancer progression. These data indicate that KDM4C is relevant for breast cancer progression and highlight its importance as a potential therapeutic target.

Thermogenic capacity of human periaortic adipose tissue is transformed by body weight

The anatomical location of adipose tissue might have direct implications for its functionality and risk of cardiovascular disease. Adipose tissue surrounding blood vessels may be thermogenically more active in specific areas of the body, releasing substances that regulate vascular metabolism. In humans, the phenotypic characteristics of adipose tissue surrounding the aorta and the cardiovascular disease risk that it might entail remain largely unknown. Here, we compared thermogenesis-related molecular features of human periaortic adipose tissue samples with those of subcutaneous adipose tissue, obtained by sternotomy from 42 patients undergoing cardiovascular surgery. To determine the expression of genes related to energy expenditure and the levels of some adipokines, histological examinations, quantitative PCR, and protein expression measurements in adipocyte precursor cells were performed. Periaortic adipocytes were smaller than those from subcutaneous tissue. Moreover, weight gain induced periaortic adipocyte hypertrophy (r = -0.91, p<0.01). Compared to subcutaneous tissue, adiponectin, FABP4, IL-4 and IL-6 was decreased in periaortic adipocytes, whereas FGF21, UCP-1, PGC-1a, CITED1, Omentin and TFAM (Mitochondrial protein) increased. Upon analyzing patients’ clinical conditions, it emerged that the levels of PGC-1a both in male (r = -0.48 p<0.04) and female (r = -0.61, p<0.05) and TFAM in male (r = -0.72, p<0.0008) and female (r = -0.86, p<0.002) decreased significantly with progressive weight gain. However, no differences were observed in patients with diabetes mellitus 2 or Hyperlipidemia. Adipocytes surrounding the ascending aorta present markers of major thermogenic activity than those in subcutaneous tissue. Nevertheless, this characteristic might change, due to unfavorable metabolic conditions such as obesity, which is a risk factor for cardiovascular disease.

The Histone Demethylase JMJD2A Modulates the Induction of Hypertrophy Markers in iPSC-Derived Cardiomyocytes

The development of cardiovascular pathologies is partly attributed to epigenetic causes, including histone methylation, which appears to be an important marker in hearts that develop cardiac hypertrophy. Previous studies showed that the histone demethylase JMJD2A can regulate the hypertrophic process in murine cardiomyocytes. However, the influence of JMJD2A on cardiac hypertrophy in a human cardiomyocyte model is still poorly understood. In the present study, cardiomyocytes derived from human induced pluripotent stem cells (iPSCs) were used. Hypertrophy was induced by angiotensin II and endothelin-1 (ET-1), and transfections were performed to overexpress JMJD2A and for small interfering RNA (siRNA)-induced silencing of JMJD2A. Gene expression analyses were determined using RT-PCR and Western blot. The expression levels of B-type natriuretic peptide (BNP), natriuretic peptide A (ANP), and beta myosin heavy chain (β-MHC) were increased by nearly 2–10-fold with ET-1 compared with the control. However, a higher level of JMJD2A and UTX was detected, whereas the level of JMJD2C was lower. When cardiomyocytes were transiently transfected with JMJD2A, an increase close to 150% in BNP was observed, and this increase was greater after treatment with ET-1. To verify the specificity of JMJD2A activity, a knockdown was performed by means of siRNA-JMJD2A, which led to a significant reduction in BNP. The involvement of JMJD2A suggests that histone-specific modifications are associated with genes encoding proteins that are actively transcribed during the hypertrophy process. Since BNP is closely related to JMJD2A expression, we suggest that there could be a direct influence of JMJD2A on the expression of BNP. These results may be studied further to reduce cardiac hypertrophy via the regulation of epigenetic modifiers.

Advances in Gut Microbiome Research, Opening New Strategies to Cope with a Western Lifestyle

The "westernization" of global eating and lifestyle habits is associated with the growing rate of chronic diseases, mainly cardiovascular diseases, cancer, type 2 diabetes mellitus, and respiratory diseases. The primary prevention approach is to make nutritional and behavioral changes, however, there is another important determinant of our health that only recently has been considered and is the presence of beneficial microorganisms and their products in our gastrointestinal tract. Microorganisms living in our body can alter the fate of food, drugs, hormones, and xenobiotics, and recent studies point to the use of microorganisms that can counteract the harmful effects of certain compounds introduced or produced endogenously in our body. This review considers the effects of the western lifestyle on adiposity, glucose metabolism, oxidative markers and inflammation profile, emphasizes on the studies that have investigated bacterial strains and products of their metabolism that are beneficial under this lifestyle, and examines the screening strategies that recent studies are using to select the most promising probiotic isolates. In addition, we consider the relevance of studying the microbiota of metabolically healthy people under a western lifestyle for the understanding of the key components that delay the development of chronic diseases.

Functional Characterization of Preadipocytes Derived from Human Periaortic Adipose Tissue

Adipose tissue can affect the metabolic control of the cardiovascular system, and its anatomic location can affect the vascular function differently. In this study, biochemical and phenotypical characteristics of adipose tissue from periaortic fat were evaluated. Periaortic and subcutaneous adipose tissues were obtained from areas surrounding the ascending aorta and sternotomy incision, respectively. Adipose tissues were collected from patients undergoing myocardial revascularization or mitral valve replacement surgery. Morphological studies with hematoxylin/eosin and immunohistochemical assay were performed in situ to quantify adipokine expression. To analyze adipogenic capacity, adipokine expression, and the levels of thermogenic proteins, adipocyte precursor cells were isolated from periaortic and subcutaneous adipose tissues and induced to differentiation. The precursors of adipocytes from the periaortic tissue accumulated less triglycerides than those from the subcutaneous tissue after differentiation and were smaller than those from subcutaneous adipose tissue. The levels of proteins involved in thermogenesis and energy expenditure increased significantly in periaortic adipose tissue. Additionally, the expression levels of adipokines that affect carbohydrate metabolism, such as FGF21, increased significantly in mature adipocytes induced from periaortic adipose tissue. These results demonstrate that precursors of periaortic adipose tissue in humans may affect cardiovascular events and might serve as a target for preventing vascular diseases.

KDM4C Activity Modulates Cell Proliferation and Chromosome Segregation in Triple-Negative Breast Cancer

The Jumonji-containing domain protein, KDM4C, is a histone demethylase associated with the development of several forms of human cancer. However, its specific function in the viability of tumoral lineages is yet to be determined. This work investigates the importance of KDM4C activity in cell proliferation and chromosome segregation of three triple-negative breast cancer cell lines using a specific demethylase inhibitor. Immunofluorescence assays show that KDM4C is recruited to mitotic chromosomes and that the modulation of its activity increases the number of mitotic segregation errors. However, 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) cell proliferation assays demonstrate that the demethylase activity is required for cell viability. These results suggest that the histone demethylase activity of KDM4C is essential for breast cancer progression given its role in the maintenance of chromosomal stability and cell growth, thus highlighting it as a potential therapeutic target.

Regulation of human subcutaneous adipocyte differentiation by EID1

Increasing thermogenesis in white adipose tissues can be used to treat individuals at high risk for obesity and cardiovascular disease. The objective of this study was to determine the function of EP300-interacting inhibitor of differentiation (EID1), an inhibitor of muscle differentiation, in the induction of beige adipocytes from adipose mesenchymal stem cells (ADMSCs). Subcutaneous adipose tissue was obtained from healthy women undergoing abdominoplasty. ADMSCs were isolated in vitro, grown, and transfected with EID1 or EID1 siRNA, and differentiation was induced after 48 h by administering rosiglitazone. The effects of EID1 expression under the control of the aP2 promoter (aP2-EID1) were also evaluated in mature adipocytes that were differentiated from ADMSCs. Transfection of EID1 into ADMSCs reduced triglyceride accumulation while increasing levels of thermogenic proteins, such as PGC1α, TFAM, and mitochondrial uncoupling protein 1 (UCP1), all of which are markers of energy expenditure and mitochondrial activity. Furthermore, increased expression of the beige phenotype markers CITED1 and CD137 was observed. Transfection of aP2-EID1 transfection induced the conversion of mature white adipocytes to beige adipocytes, as evidenced by increased expression of PGC1α, UCP1, TFAM, and CITED1. These results indicate that EID1 can modulate ADMSCs, inducing a brown/beige lineage. EID1 may also activate beiging in white adipocytes obtained from subcutaneous human adipose tissue.

Biology of Beige Adipocyte and Possible Therapy for Type 2 Diabetes and Obesity

All mammals own two main forms of fat. The classical white adipose tissue builds up energy in the form of triglycerides and is useful for preventing fatigue during periods of low caloric intake and the brown adipose tissue instead of inducing fat accumulation can produce energy as heat. Since adult humans possess significant amounts of active brown fat depots and their mass inversely correlates with adiposity, brown fat might play an important role in human obesity and energy homeostasis. New evidence suggests two types of thermogenic adipocytes with distinct developmental and anatomical features: classical brown adipocytes and beige adipocytes. Beige adipocyte has recently attracted special interest because of its ability to dissipate energy and the possible ability to differentiate itself from white adipocytes. Importantly, adult human brown adipocyte appears to be mainly composed of beige-like adipocytes, making this cell type an attractive therapeutic target for obesity and obesity-related diseases. Because many epigenetic changes can affect beige adipocyte differentiation, the knowledge of the circumstances that affect the development of beige adipocyte cells may be important for therapeutic strategies. In this review we discuss some recent observations arising from the great physiological capacity of these cells and their possible role as ways to treat obesity and diabetes mellitus type 2.

[Latin American consensus on hypertension in patients with diabetes type 2 and metabolic syndrome]

The present document has been prepared by a group of experts, members of cardiology, endocrinology, internal medicine, nephrology and diabetes societies of Latin American countries, to serve as a guide to physicians taking care of patients with diabetes, hypertension and comorbidities or complications of both conditions. Although the concept of metabolic syndrome is currently disputed, the higher prevalence in Latin America of that cluster of metabolic alterations has suggested that metabolic syndrome is a useful nosography entity in the context of Latin American medicine. Therefore, in the present document, particular attention is paid to this syndrome in order to alert physicians on a particular high-risk population, usually underestimated and undertreated. These recommendations result from presentations and debates by discussion panels during a 2-day conference held in Bucaramanga, in October 2012, and all the participants have approved the final conclusions. The authors acknowledge that the publication and diffusion of guidelines do not suffice to achieve the recommended changes in diagnostic or therapeutic strategies, and plan suitable interventions overcoming knowledge, attitude and behavioural barriers, preventing both physicians and patients from effectively adhering to guideline recommendations.

Estrogen Deficiency and the Origin of Obesity during Menopause

Sex hormones strongly influence body fat distribution and adipocyte differentiation. Estrogens and testosterone differentially affect adipocyte physiology, but the importance of estrogens in the development of metabolic diseases during menopause is disputed. Estrogens and estrogen receptors regulate various aspects of glucose and lipid metabolism. Disturbances of this metabolic signal lead to the development of metabolic syndrome and a higher cardiovascular risk in women. The absence of estrogens is a clue factor in the onset of cardiovascular disease during the menopausal period, which is characterized by lipid profile variations and predominant abdominal fat accumulation. However, influence of the absence of these hormones and its relationship to higher obesity in women during menopause are not clear. This systematic review discusses of the role of estrogens and estrogen receptors in adipocyte differentiation, and its control by the central nervous systemn and the possible role of estrogen-like compounds and endocrine disruptors chemicals are discussed. Finally, the interaction between the decrease in estrogen secretion and the prevalence of obesity in menopausal women is examined. We will consider if the absence of estrogens have a significant effect of obesity in menopausal women.

Diverse coactivator recruitment through differential PPARγ nuclear receptor agonism

The PPARγ nuclear receptor regulates the expression of genes involved in lipid and carbohydrate metabolism, and it has protective effects in some patients with type 2 diabetes. Nevertheless, the therapeutic value of the PPARγ nuclear receptor protein is limited due to the secondary effects of some PPARγ ligands. Because the downstream effects of PPARγ are determined by the binding of specific cofactors that are mediated by ligand-induced conformational changes, we evaluated the differential effects of various ligands on the binding of certain cofactors associated with PPARγ. The ligands used were rosiglitazone for treating type 2 diabetes and telmisartan for treating arterial hypertension. Functional, phenotypic, and molecular studies were conducted on pre-adipocyte 3T3-L1 and functional studies in U2OS cells. The moderating influence of various cofactor families was evaluated using transient transfection assays. Our findings confirm that telmisartan has a partial modulating effect on PPARγ activity compared to rosiglitazone. The cofactors SRC1 and GRIP1 mediate the activity of telmisartan and rosiglitazone and partially determine the difference in their effects. Studying the modulating activity of these cofactors can provide interesting insights for developing new therapeutic approaches for certain metabolic diseases.

Caracterización Histológica E Inmunocitoquímica de la Grasa Infrapatelar de Hoffa

El presente estudio tuvo como objetivo la caracterización histológica e inmunocitoquímica de la grasa infrapatelar de Hoffa (GIH) en 12 pacientes intervenidos por artroscopia, meningoplastia o remplazo de rodilla. Las fibras elásticas estuvieron presentes en la grasa infrapatelar con distribución unidireccional fascicular, se plantea una relación funcional en la biomecánicas del movimiento articular de la rodilla. Por otra parte las pruebas de inmunocitoquimica arrojaron marcaje positivo para vimentina, marcador de células del tejido conectivo; células mesenquimales y negativo para el resto de los anticuerpos estudiados.

Regulation of adipogenesis by nuclear receptor PPARγ is modulated by the histone demethylase JMJD2C

A potential strategy to combat obesity and its associated complications involves modifying gene expression in adipose cells to reduce lipid accumulation. The nuclear receptor Peroxisome Proliferator-activated receptor gamma (PPARγ) is the master regulator of adipose cell differentiation and its functional activation is currently used as a therapeutic approach for Diabetes Mellitus type 2. However, total activation of PPARγ induces undesirable secondary effects that might be set with a partial activation. A group of proteins that produce histone demethylation has been shown to modify the transcriptional activity of nuclear receptors. Here we describe the repressive action of the jumonji domain containing 2C/lysine demethylase 4 C (JMJD2C/KDM4C) on PPARγ transcriptional activation. JMJD2C significantly reduced the rosiglitazone stimulated PPARγ activation. This effect was mainly observed in experiments performed using the Tudor domains that may interact with histone deacetylase class 1 (HDAC) and this interaction probably reduces the mediated activation of PPARγ. Trichostatin A, a HDAC inhibitor, reduces the repressive effect of JMJD2C. When JMJD2C was over-expressed in 3T3-L1 cells, a reduction of differentiation was observed with the Tudor domain. In summary, we herein describe JMJD2C-mediated reduction of PPARgamma transcriptional activation as well as preadipocyte differentiation. This novel action of JMJD2C might have an important role in new therapeutic approaches to treat obesity and its complications.

Thyroid hormone therapy modulates hypothalamo-pituitary-adrenal axis

To observe the influence of thyroid hormone therapy on hypothalamo-pituitary-adrenal (HPA) axis, a group of 14 athyreotic women due to thyroid cancer treatment were studied before and after thyroid suppression therapy with thyroxine (T4). Changes in plasma adrenocorticotropin (ACTH) and cortisol levels in response to human corticotropin-releasing hormone (hCRH; 100µg, i.v.) were estimated under hypothyroid conditions and after T4 suppression therapy with 2.5µg/kg/day for two months (n=14). A group of seven healthy women was evaluated as a control group. A greater increase in ACTH levels by hCRH was observed in patient group both before and after suppression therapy compared than that of control group. Plasma cortisol levels after hCRH stimulation were also greater in patient group both before and after suppression therapy than that of control group. In conclusion, both hypothyroidism and subclinical hyperthyroidism with suppressive doses of thyroid hormone induced a hypersensitivity of ACTH to hCRH. Considering the role of thyroid hormone on HPA axis, the mechanisms of ACTH hypersensitivity may be different between these two conditions.

Efecto del Ácido Valproico, Tricostatin a y Resveratrol Sobre la Diferenciación del Adipocito

<p>La obesidad es un factor de riesgo de enfermedades coronarias, de cáncer, de accidentes cerebrovasculares y de diabetes tipo II. El propósito de este trabajo es evaluar la capacidad del ácido valproico, tricostatin A y resveratrol como agentes que reduzcan la diferenciación de preadipocitos. Los dos primeros, inhiben la actividad de las histonas deacetilasas tipo I y II, mientras que el resveratrol es un activador de la enzima sirtuina 1 perteneciente a la familia de las histonas deacetilasas dependientes de dinucleótidos de nicotinamida adenina. Esta reprime la actividad trascripcional mediada por el receptor de proliferación del peroxisoma mediante su asociación con represores, evidenciado en la movilización de ácidos grasos en células adiposas.</p><p>Para el estudio se utilizó la línea celular de preadipocitos de ratón 3T3-L1 en presencia de un cóctel de diferenciación con rosiglitazona, isobutilmetilxantina y dexametasona. Al día 8 de la diferenciación, se aplicaron las dosis de los tres agentes objeto de estudio y se llevaron a cabo observaciones cada dos días hasta el día 12. Se evaluó la acumulación de depósitos de grasa mediante tinción rojo-aceite y se cuantificaron la cantidad de triglicéridos en cada tratamiento. El ácido valproico, tricostatin A y resveratrol presentaron una disminución en la diferenciación del adipocito maduro, debido a que la cantidad de triglicéridos dentro del mismo fue menor con respecto a las células tratadas con ROSI. Sin embargo, el resveratrol presenta una mayor diferencia significativa. Nuestros resultados destacan el papel de los inhibidores de las histonas deacetilasas y la actividad de sirtuina 1 en la adipogénesis que es bloqueada por los tratamientos con los tres agentes, siendo el resveratrol el agente que presenta mayor reducción de la diferenciación del adipocito.</p>

Functional Characterization of JMJD2A, a Histone Deacetylase- and Retinoblastoma-binding Protein

To effectively direct targeted repression, the class I histone deacetylases (HDACs) associate with many important regulatory proteins. In this paper we describe the molecular characterization of a member of the Jumonji domain 2 (JMJD2) family of proteins, and demonstrate its binding to both class I HDACs and the retinoblastoma protein (pRb). JMJD2 proteins are characterized by the presence of two leukemia-associated protein/plant homeodomain (LAP/PHD) zinc fingers, one JmjN, one JmjC (containing an internal retinoblastoma-binding protein 2 (RBBP2)-like sequence), and two Tudor domains. The first member of this group, JMJD2A, is widely expressed in human tissues and cell lines, and high endogenous expression of JMJD2A mRNA was found in several cell types, including human T-cell lymphotropic virus 1 (HTLV-1)-infected cell lines. JMJD2A and JMJD2B exhibit cell type-specific responses to the HDAC inhibitor trichostatin A. We show that the JMJD2A protein associates in vivo with pRb and class I HDACs, and mediates repression of E2F-regulated promoters. In HTLV-1 virus-infected cells, we find that JMJD2A binds to the viral Tax protein. Antibodies to JMJD2A recognize the native protein but also a half-sized protein fragment, the latter up-regulated in THP-1 cells during the G(2)/M phase of the cell cycle. The ability of JMJD2A to associate with pRb and HDACs and potentiate pRb-mediated repression of E2F-regulated promoters implies an important role for this protein in cell proliferation and oncogenesis.

Cell type-specific roles of histone deacetylase in TR ligand-independent transcriptional repression

Recent evidence indicates that corepressor protein with histone deacetylase (HDAC) activity mediates thyroid hormone receptor (TR) transcriptional repression. In order to examine the physiological relevance of HDAC in ligand-independent TR-mediated repression, we studied the effect of trichostatin A (TSA), a specific HDAC inhibitor, in transient transfection studies with natural reporters, and assessed the expression of TR-regulated endogenous genes. Luciferase-coupled DR4-, F2-, PAL- or GH-TREs and TRbeta1 expression vectors were cotransfected in CV-1 and GH(3) cells. We did not observe any effect of TSA on TR-induced basal repression in CV-1 cells. Instead, TSA was able to induce an increase in transcription without T(3) on all TREs tested in GH(3) cells. This increase was >7-fold on F2-, >4-fold on DR4-, and 3-fold on GH-TREs. The cotransfection of a TRbeta1 mutant that exhibits decreased affinity with N-CoR (AHT) reduced the TSA effect in GH(3) cells, demonstrating a primary role for TR/N-CoR/Sin3/HDAC complex. Next, we examined the effects of TSA on endogenous GH mRNA production in GH(3) cells by Northern blot analysis. We observed an increase of 50-70% of GH mRNA in cells treated with TSA in hypothyroid medium, and an increase of GH mRNA in T(3)-treated cells after TSA treatment. Our results show that TSA can increase the expression of endogenous genes that are susceptible to TR regulation. These results support an active role of HDAC in transcriptional repression by ligand-independent TR.

Cholinergic modulation of spontaneous hypothalamic-pituitary-adrenal activity and its circadian variation in man

Controversy still exists regarding the role of cholinergic pathways in the regulation of the hypothalamic-pituitary-adrenal axis in man. We studied the effects of the administration of placebo, pyridostigmine (PD); 120 mg, orally), and the combination of PD and pirenzepine (PZP; 100 mg, orally) on ACTH, cortisol, and GH secretion at 0730 and 2230 h in seven normal males. PD induced a clear decrease in ACTH levels at both times of the day compared to treatment with placebo, producing higher suppression in the nocturnal period (34.4 +/- 5.8% vs. 21.8 +/- 10.7%). The combination PD and PZP prevented the inhibitory action of PD on ACTH secretion in the morning, but not in the evening, when ACTH values showed a decrease similar to that seen after giving PD alone (38.1 +/- 5.6% vs. 34.4 +/- 5.8%, respectively). Cortisol values declined only when the association PD plus PZP was given in the evening. GH levels had a significant increase after PD administration in the morning (4.1 +/- 1.2 ng/mL) and in the evening (10.2 +/- 1.6 ng/mL), confirming that cholinergic stimulation was taking place, whereas the addition of PZP to PD induced a significant attenuation of these responses. It is concluded that cholinergic pathways have a inhibitory role in ACTH secretion in man. M1 muscarinic receptors seem to be involved in the diurnal inhibition of PD, whereas our observations are consistent with the mediation of another type of cholinergic receptors as an explanation for the nocturnal effect of PD on ACTH secretion. PD did not alter the circadian variation in the hypothalamic-pituitary-adrenal axis, whereas the association of PD and PZP increased the differences between diurnal and nocturnal ACTH values, suggesting a modulatory effect of the cholinergic system on the circadian rhythm of ACTH secretion.

[Clinical usefulness of the glucagon test in the study of pancreatic islet cell function]

In an attempt to assess the utility of glucagon test as an index of beta cell function, we have studied the C-Peptide response to intravenous injection of 1 mg of glucagon in 77 patients with type I diabetes, 27 type II diabetics and 14 normal subjects. A significant difference between basal and glucagon-stimulated C-Peptide levels as well as a good relationship between both values were observed in all groups (r values 0.91, 0.80 and 0.89 respectively). Both basal and stimulated C-Peptide concentrations showed significant relationship with the body mass index and total cholesterol levels, whereas both parameters were negatively related to insulin requirements in type I diabetic group. Absolute C-Peptide increment was different in all groups, despite it was not related to basal C-Peptide levels. These findings confirm the usefulness of glucagon test as an investigative tool to assess the secretory capacity of beta-cell, suggesting that estimation of C-Peptide increment represents the best parameter to evaluate beta-cell reserve.