Impaired growth hormone secretion associated with low glucocorticoid levels: an experimental model for the Giustina effect

The Growing Understanding of the Pituitary Implication in the Pathogenesis of Long COVID-19 Syndrome: A Narrative Review

Long COVID-19, also known as post-acute sequelae of SARS-CoV-2 infection, is a condition where individuals who have recovered from the acute phase of COVID-19 continue to experience a range of symptoms for weeks or even months afterward. While it was initially thought to primarily affect the respiratory system, it has become clear that Long COVID-19 can involve various organs and systems, including the endocrine system, which includes the pituitary gland. In the context of Long COVID-19, there is a growing understanding of the potential implications for the pituitary gland. The virus can directly affect the pituitary gland, leading to abnormalities in hormone production and regulation. This can result in symptoms such as fatigue, changes in appetite, and mood disturbances. Long COVID-19, the persistent and often debilitating condition following acute COVID-19 infection, may be explained by deficiencies in ACTH and Growth hormone production from the pituitary gland. Corticotropin insufficiency can result in the dysregulation of the body's stress response and can lead to prolonged feelings of stress, fatigue, and mood disturbances in Long COVID-19 patients. Simultaneously, somatotropin insufficiency can affect growth, muscle function, and energy metabolism, potentially causing symptoms such as muscle weakness, exercise intolerance, and changes in body composition. Recently, some authors have suggested the involvement of the pituitary gland in Post COVID-19 Syndrome. The exact mechanisms of viral action on infected cells remain under discussion, but inflammatory and autoimmune mechanisms are primarily implicated. The aim of our study will be to review the main pituitary complications following COVID-19 infection. Moreover, we will explain the possible involvement of the pituitary gland in the persistence of Post COVID-19 Syndrome.

Positive programming of the GC-IGF1 axis mediates adult osteoporosis susceptibility in male offspring rats induced by prenatal dexamethasone exposure

Prenatal dexamethasone exposure (PDE) can lead to offspring long bone dysplasia and continue to postnatal, and this is an important cause of fetal-derived osteoporosis. Studies have confirmed that intrauterine endogenous GC overexposure mediates multiple organ dysplasia and adult-related disease susceptibility in offspring through the glucocorticoid-insulin-like growth factor1 (GC-IGF1) axis. However, it remains unknown if exogenous dexamethasone can regulate bone development in offspring through the GC-IGF1 axis. We determined that the PDE fetal rats exhibited poor osteogenic differentiation, decreased bone mass that continued to adolescence, and increased susceptibility to osteoporosis in adulthood. Concurrently, PDE decreased the serum corticosterone concentration and IGF1 expression in offspring before and after birth, while the increased serum corticosterone concentration induced by chronic stress reversed the inhibition of IGF1 expression induced by PDE. Furthermore, PDE decreased the expression of GRα and miR-130a-5p, increased HDAC4, and decreased H3K27 acetylation in the IGF1 promoter region in bone tissue, and the above changes were negatively compensated after chronic stress. In vitro, a low concentration of corticosterone inhibited the expression of GRα and miR130a-5p, upregulated the expression of HDAC4, inhibited the promoter region H3K27 acetylation, and expression of IGF1 in bone marrow mesenchymal stem cell (BMSCs) osteoblast differentiated cells and inhibited osteogenic differentiation of BMSCs. GRα overexpression, miR-130a-5p mimic treatment, or HDAC4 siRNA exposure reversed the downstream molecular alterations caused by low corticosterone concentrations. In conclusion, PDE-induced intrauterine hypoglucocorticoid exposure could positively program IGF1 expression in bone tissue through the GRα/miR-130a-5p/HDAC4 pathways, thus mediating osteogenic dysdifferentiation and adult osteoporosis susceptibility in male offspring rats.

Effects of Medical Treatment of Prostate Cancer on Bone Health

Medical treatment of prostate cancer (PC) is multidisciplinary, resulting in prolonged survival. Androgen-deprivation therapy (ADT) can have negative effects on skeletal metabolism, particularly if combined with glucocorticoids. We discuss the pathophysiology and effects of ADT and glucocorticoids on skeletal endpoints, as well as the awareness and management of bone fragility. Coadministration of glucocorticoids is necessary with abiraterone because this causes a novel acquired form of 17-hydroxylase deficiency and synergistically increases the risk of fracture by affecting bone quality. Bone antiresorptive agents [selective estrogen receptor modulators (SERMS), bisphosphonates, and denosumab] increase bone mineral density (BMD) and in some instances reduce fracture risk in PC patients on ADT. Awareness and management of bone health in PC can be improved by integrating endocrinologists into the multidisciplinary PC team.

Osteopathy in mild adrenal Cushing's syndrome and Cushing disease

Pathophysiology and effects of endogenous glucocorticoid (GC) excess on skeletal endpoints as well as awareness and management of bone fragility are reviewed. Cushing's syndrome (CS) increase the risk of fracture affecting prevalently bone quality. Bone antiresorptive agents (SERMs, bisphosphonates and denosumab) as well as teriparatide increase bone mineral density and in some instances reduce fracture risk. Awareness and management of bone health in CS can be improved.

Plasmatic free light chains as inflammatory marker in insulin resistance: comparison of metabolic syndrome with adult growth hormone deficiency

Biological functions of immunoglobulin-free light chains (FLCs), other than in chronic inflammatory diseases, are still poorly defined; the field of insulin resistance (IR) has not been investigated, despite the strict relationships with oxidative stress (OS) and inflammation. Therefore, we evaluated FLCs levels and their relationships with metabolic parameters in adult growth hormone deficiency (GHD) and metabolic syndrome (MetS), both characterized by IR. One hundred subjects were enrolled: group A, patients with GHD [n =31, 24-69 years, mean ± SEM body mass index (BMI) 26.8 ± 1.5 kg/m² ]; group B, patients with MetS (n = 29, 21-70 years, BMI 31.9 ± 1.3); group C, controls (N = 40, 21-62 years, BMI 21.6 ± 1.1). Groups were matched by age range and, for patients, by BMI. Morning blood sample was collected for metabolic parameters and FLCs, assessed by turbidimetric assay. GHD patients show levels of FLCs significantly higher than MetS and controls (mean ± SEM κ 37.21 ± 6.97, 15.27 ± 0.86, 12.34 ± 0.85 mg/l; λ 19.44 ± 2.61, 11.78 ± 0.72 and 11.67 ± 0.77 mg/l; κ/λ ratio 1.77 ± 0.13, 1.38 ± 0.09; and 1.10 ± 0.06, respectively); only κ were higher in MetS versus controls. Therefore, the ratio showed progressive declining values in GHD versus MetS versus controls. Our data show increased FLCs levels in GHD and MetS, with the highest values in the former. Both conditions show OS, but with different molecular patterns. FLCs may contribute to chronic inflammation, leading to OS, and cardiovascular complications of GHD. Prognostic and therapeutic implications require further investigation. © 2018 BioFactors, 44(5):480-484, 2018.

Pituitary Diseases and Bone

Neuroendocrinology of bone is a new area of research based on the evidence that pituitary hormones may directly modulate bone remodeling and metabolism. Skeletal fragility associated with high risk of fractures is a common complication of several pituitary diseases such as hypopituitarism, Cushing disease, acromegaly, and hyperprolactinemia. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density as measured by dual-energy X-ray absorptiometry, making difficult the prediction of fractures in these clinical settings. Treatment of pituitary hormone excess and deficiency generally improves skeletal health, although some patients remain at high risk of fractures, and treatment with bone-active drugs may become mandatory. The aim of this review is to discuss the physiological, pathophysiological, and clinical insights of bone involvement in pituitary diseases.

MANAGEMENT OF ENDOCRINE DISEASE: Risk of overtreatment in patients with adrenal insufficiency: current and emerging aspects

The effects of long-term replacement therapy of adrenal insufficiency (AI) are still a matter of controversy. In fact, the established glucocorticoid replacement regimens do not completely reproduce the endogenous hormonal production and the monitoring of AI treatment may be a challenge for the lack of reliable clinical and biochemical markers. Consequently, several AI patients are frequently exposed to relative glucocorticoid excess potentially leading to develop chronic complications, such as diabetes mellitus, dyslipidemia, hypertension and fragility fractures with consequent impaired QoL and increased mortality risk. This review deals with the pathophysiological and clinical aspects concerning the over-replacement therapy of primary and secondary AI.

Growth hormone deficiency in treated acromegaly and active Cushing's syndrome

Growth hormone deficiency (GHD) in adults is characterized by reduced quality of life and physical fitness, skeletal fragility, increased weight and cardiovascular risk. It may be found in (over-) treated acromegaly as well as in active Cushing's syndrome. Hypopituitarism may develop in patients after definitive treatment of acromegaly, although the exact prevalence of GHD in this population is still uncertain because of limited awareness, and scarce and conflicting data so far available. Because GHD associated with acromegaly and Cushing's syndrome may yield adverse consequences on similar target systems, the final outcomes of some complications of both acromegaly and Cushing's syndrome may be further affected by the occurrence of GHD. It is still largely unknown, however, whether GHD in patients with post-acromegaly or active Cushing's syndrome (e.g. pharmacologic glucocorticoid treatment) may benefit from GH replacement. We review the diagnostic, clinical and therapeutic aspects of GHD in adults treated for acromegaly and in those with active Cushing's syndrome.

Glucocorticoid-induced osteoporosis: pathophysiological role of GH/IGF-I and PTH/VITAMIN D axes, treatment options and guidelines

Glucocorticoid-induced osteoporosis is the most frequent form of secondary osteoporosis caused by chronic exposure to glucocorticoid excess. Pathogenesis of glucocorticoid-induced osteoporosis is multifactorial including direct effects of glucocorticoids on bone cells and indirect effects of glucocorticoids on several neuroendocrine and metabolic pathways. Fragility fractures occur early in glucocorticoid-induced osteoporosis and anti-osteoporotic drugs along with calcium and vitamin D should be started soon after exposure to glucocorticoid excess. This paper summarizes some of the main topics discussed during the 9th Glucocorticoid-Induced Osteoporosis Meeting (Rome, April 2016) with a specific focus on the role of growth hormone/insulin-like growth factor-1 and parathyroid hormone/vitamin D axes in the pathogenesis of glucocorticoid-induced osteoporosis and the controversial aspects concerning therapeutic approach to skeletal fragility in this clinical setting.

Developmental programming: the role of growth hormone

Developmental programming of the fetus has consequences for physiologic responses in the offspring as an adult and, more recently, is implicated in the expression of altered phenotypes of future generations. Some phenotypes, such as fertility, bone strength, and adiposity are highly relevant to food animal production and in utero factors that impinge on those traits are vital to understand. A key systemic regulatory hormone is growth hormone (GH), which has a developmental role in virtually all tissues and organs. This review catalogs the impact of GH on tissue programming and how perturbations early in development influence GH function.

Parathyroid hormone pulsatility: physiological and clinical aspects

Parathyroid hormone (PTH) secretion is characterized by an ultradian rhythm with tonic and pulsatile components. In healthy subjects, the majority of PTH is secreted in tonic fashion, whereas approximately 30% is secreted in low-amplitude and high-frequency bursts occurring every 10–20 min, superimposed on tonic secretion. Changes in the ultradian PTH secretion were shown to occur in patients with primary and secondary osteoporosis, with skeletal effects depending on the reciprocal modifications of pulsatile and tonic components. Indeed, pathophysiology of spontaneous PTH secretion remains an area potentially suitable to be explored, particularly in those conditions such as secondary forms of osteoporosis, in which conventional biochemical and densitometric parameters may not always give reliable diagnostic and therapeutic indications. This review will highlight the literature data supporting the hypothesis that changes of ultradian PTH secretion may be correlated with skeletal fragility in primary and secondary osteoporosis.

Growth hormone deficiency in treated acromegaly

Growth hormone deficiency (GHD) of the adult is characterized by reduced quality of life (QoL) and physical fitness, skeletal fragility, and increased weight and cardiovascular risk. Hypopituitarism may develop in patients after definitive treatment of acromegaly, but an exact prevalence of GHD in this population is still uncertain owing to limited awareness and the scarce and conflicting data available on this topic. Because acromegaly and GHD may yield adverse consequences on similar target systems, the final outcomes of some complications of acromegaly may be further affected by the occurrence of GHD. However, it is still largely unknown whether patients with post-acromegaly GHD may benefit from GH replacement. We review the diagnostic, clinical, and therapeutic aspects of GHD in adult patients treated for acromegaly.