Frontiers of Hormone Research最新文献

Prevalence of metabolic syndrome (MetS) and mortality rates from cardiovascular causes are increased in patients with hypopituitarism. Features of obesity, visceral adiposity, dyslipidemia, insulin resistance, and hypertension are common in these patients. Unreplaced growth hormone (GH) deficiency and inadequate replacement of other hormone insufficiencies may be responsible for the adverse body composition and metabolic profile associated with hypopituitarism. Recently, fatty liver disease was added to this unfavorable metabolic phenotype. Long-term treatment with low-dose GH replacement is considered safe and advantageous for metabolic profile and normalization of cardiovascular mortality rates in hypopituitary patients. Positive influence of optimal balance in replacement of other pituitary hormone deficiencies with doses of hydrocortisone (<20 mg/day), weight-adjusted T4 doses, and transdermal estrogen in women is also very important. Active screening and treatment of all cardiometabolic risk factors and comorbidities may further improve outcomes in patients with hypopituitarism.

Cancer and autoimmune diseases are often associated in the same individual. The functional link between the immune system and cancer development is only partially known. Even though the immune system can control the development of cancer through immune surveillance, cancer cell can escape it. It is debated whether autoimmune diseases have to be regarded as a cancer cause or its consequence. In particular, the association between autoimmune thyroiditis and thyroid cancer (TC; especially papillary carcinoma) is a fascinating model of this complex relationship. In this review, we present data reported in literature about autoimmune thyroiditis and papillary TC, and on the basis of available data, we try to clarify the present knowledge.

Pituitary-specific transcription factor 1 (PIT-1; POU domain, class 1, transcription factor 1 (POU1F1)) is an essential transcription factor for the differentiation of somatotrophs, lactotrophs, and thyrotrophs, and for the expression of growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH). Mutations in PIT-1 cause congenital defects in GH and PRL secretion and severe TSH insufficiency. Anti-PIT-1 antibody syndrome, firstly reported in 2011, is characterized by acquired GH, PRL, and TSH deficiencies without PIT-1 mutation and is associated with the presence of the circulating antibody against PIT-1 protein as a marker. Various autoantibodies are detected with multiple endocrine organopathies in this syndrome; therefore, it meets the criteria of autoimmune polyglandular syndrome. Mechanistically, cytotoxic T lymphocytes specifically reacting with PIT-1 protein play an important role in the development of this syndrome.

Since the mid 1900s, a significant increase of infectious, hematological, and autoimmune diseases has been reported in patients with Down's syndrome (DS), independent of sex, age, family history, and exposure to other risk factors, suggesting an intrinsic alteration of the immune system. Several in vitro and in vivo studies have demonstrated alterations of both cellular and humoral immunological response mainly, although not exclusively, secondary to alterations of the expression of autoimmune regulator gene (located on chromosome 21), leading to thymic structural and functional impairments. Autoimmune thyroid disorders (i.e. Hashimoto's thyroiditis and Graves' disease) and type 1 diabetes mellitus are the most common autoimmune endocrine disorders associated with DS, and present with some peculiar features. The underlying etiopathogenic mechanisms and clinical significance of some mild laboratory alterations are still poorly understood. For these aspects, together with the associated multiple comorbidities and intellectual impairment - that make DS patients dependent on care givers - and in the absence of definite guidelines, disease management is very challenging and should be patient-tailored.

The immune system is faced with the daunting job of defending the organism against invading pathogens, while at the same time preserving the body integrity and maintaining tolerance to its own tissues. Loss of self-tolerance compromises immune homeostasis and leads to the onset of autoimmune disorders. The identification of endogenous factors that control immune tolerance and inflammation is a key goal for immunologists. Evidences from the last decade indicate that the neuropeptide cortistatin is one of the endogenous factors. Cortistatin is produced by immune cells and through its binding to various receptors, it exerts potent anti-inflammatory actions and participates in the maintenance of immune tolerance at multiple levels, especially in immunological disorders. Cortistatin emerges as a key element in the bidirectional communication between the neuroendocrine and immune systems aimed at regulating body homeostasis.

From the middle of the 19th century, it is known that endocrine and immune systems interact bi-directionally in different processes that ensure organism homeostasis. Endocrine and nervous systems have a pivotal role in the balancing of pro- and anti-inflammatory functions of immune system, and constitute a complex circadian neuroendocrine network. Autoimmune diseases have in fact a complex pathogenic origin in which the importance of endocrine system was demonstrated. In this chapter, we will mention the structure and function of steroidal hormones involved in the neuroendocrine immune network and we will address the ways in which endocrine and immune systems influence each other, in a bi-directional fashion. Adrenal hormones, sex hormones, vitamin D, and melatonin and prolactin importantly all contribute to the homeostasis of the immune system. Indeed, some of the steroidal hormone activities determine inhibition or stimulation of immune system components, in both physiological (i.e. suppression of an unwanted response in pregnancy, or stimulation of a protective response in infections) and pathological conditions. We will finally mention the rationale for optimization of exogenous administration of glucocorticoids in chronic autoimmune diseases, and the latest developments concerning these drugs.

Most scientific reports debate the thymotropic and immuno-stimulating properties of the somatotrope growth hormone-releasing hormone (GHRH)/growth hormone (GH)/insulin-like growth factor (IGF)-1 axis, but there is still some disagreement about the physiological role of this axis in basal conditions. Moreover, some authors have hypothesized that the physiological role of the somatotrope axis only appears in stressful conditions (such as sepsis or infective and inflammatory diseases). This chapter will provide an extended overview of the expression of the components (signals and receptors) of the somatotrope axis and their properties on cells of the innate and adaptive immune system. It will also summarize some clinical studies suggesting a benefit for a short-term GH treatment in acute immunodeficiencies, and the importance of GH supplementation in adult GH deficiency. A new transgenic mouse model, the hypothalamic GHRH-deficient (Ghrh-/-) mouse, which exhibits a severe deficiency of the somatotrope axis, will be presented since it will be of great help in further deciphering the regulation by the GHRH/GH/IGF-1 axis on both immune development and function. Finally, we will discuss the implication of aging-related somatopause in relation to the general context of Immunosenescence.

The thymus is primarily responsible for T cell production. However, it begins to recede in size and function, from early in life. This decreased generation of naive T cells during normal thymus ageing, or linked with pathology (i.e. chronic inflammation), leads to reduced T cell specificities, peripheral T cell imbalances, and higher susceptibilities to infections. Various clinical strategies for thymus and T cell recovery have been investigated, although no effective clinical treatments for the reconstitution of peripheral T cell diversity in severe immune deficiencies are available. The recent identification of thymic epithelial progenitor cells (TEPC) in the adult thymus will enable investigations into a new generation of therapies focused on regenerating the thymic microenvironment for diverse specificity T cell reconstitution in the elderly. The specific mechanisms underlying TEPC activation are still being investigated. Recent data point to an important role of the intrathymic transforming growth factor-β (TGF-β) circuitry. Although dual actions of this cytokine have been reported in the immune system, TGF-β signaling is transiently activated in hematopoietic stem and progenitor cells during hematopoietic regeneration. This review investigates the current strategies for thymus reactivation to replenish the peripheral T cell repertoire and potentially reverse the age-related inflammatory milieu.

Various lines of evidence show that prolactin (PRL) is an immunomodulator in health and disease. Cells of the immune system express PRL receptors and respond to the cognate ligand. Also, PRL itself is produced by several immune cells, indicating that in addition to its classic endocrine effects, it may also act via paracrine/autocrine pathways. PRL stimulates B and T lymphocyte proliferation, and its excess is associated with the appearance or recrudescence of various systemic and organ-specific autoimmune diseases, as demonstrated by experimental studies performed in mice, and by human case reports and case control studies. Very recently, dopamine agonists have been demonstrated to be efficacious in the treatment of some autoimmune disorders, placing PRL-mediated interactions as potential therapeutic targets for treating autoimmunity.