Growth hormone, insulin-like growth factor-1, and the kidney: pathophysiological and clinical implications

Tackling access and payer barriers for growth hormone therapy in Saudi Arabia: a consensus statement for the Saudi Working Group for Pediatric Endocrinology

Prompt diagnosis and early treatment are key goals to optimize the outcomes of children with growth hormone deficiency (GHD) and attain the genetically expected adult height. Nonetheless, several barriers can hinder prompt diagnosis and treatment of GHD, including payer-related issues. In Saudi Arabia, moderate-to-severe short stature was reported in 13.1 and 11.7 % of healthy boys and girls, respectively. Several access and payer barriers can face pediatric endocrinologists during the diagnosis and treatment of GHD in Saudi Arabia. Insurance coverage policies can restrict access to diagnostic tests for GHD and recombinant human growth hormone (rhGH) due to their high costs and lack of gold-standard criteria. Some insurance policies may limit the duration of treatment with rhGH or the amount of medication covered per month. This consensus article gathered the insights of pediatric endocrinologists from Saudi Arabia to reflect the access and payer barriers to the diagnostic tests and treatment options of children with short stature. We also discussed the current payer-related challenges endocrinologists face during the investigations of children with short stature. The consensus identified potential strategies to overcome these challenges and optimize patient management.

Gut development following insulin-like growth factor-1 supplementation to preterm pigs

BACKGROUND

Reduced insulin-like growth factor-1 (IGF-1) levels may contribute to impaired organ development in preterm infants. Using preterm pigs as a model, we hypothesized that IGF-1 supplementation improves health and gut development during the first three weeks of life.

METHODS

First, clinical and organ endpoints were compared between artificially-reared, cesarean-delivered preterm pigs and vaginally-delivered, sow-reared term pigs at 5, 9 and 19 days. Next, preterm pigs were treated with recombinant human IGF-1 for 19 days (2.25 mg/kg/day, systemically).

RESULTS

Relative to term pigs, preterm pigs had lower body weight, fat, bone contents, relative weights of liver and spleen and a longer and thinner intestine at 19 days. Preterm birth reduced intestinal villi heights and peptidase activities, but only at 5 and 9 days. In preterm pigs, IGF-1 reduced mortality primarily occurring from gastrointestinal complications and with a tendency towards salvaging smaller pigs. IGF-1 supplementation also increased spleen and kidney weights, small intestine length and maltase to lactase activity, reflecting gut maturation.

CONCLUSION

Preterm birth affects body composition and gut maturation in the first 1-2 weeks, but differences are marginal thereafter. Supplemental IGF-1 may improve gut health in pigs and infants in the first few weeks after preterm birth.

IMPACT

Insulin-like growth factor 1 (IGF-1) supplementation may improve gut health and development in prematurity, but whether the effects are sustained beyond the immediate postnatal period is unclear. In preterm pigs, the prematurity effects on IGF-1 and gut health deficiencies are most pronounced during the first week of life and diminishes thereafter. In preterm pigs, IGF-1 supplementation beyond the first week of life reduced mortality. The present study provides evidence of a sustained effect of IGF-1 supplementation on the gastrointestinal tract after the immediate postnatal period.

Co-differential genes between DKD and aging: implications for a diagnostic model of DKD

Objective

Diabetic kidney disease (DKD) is a serious complication of diabetes mellitus (DM) that is closely related to aging. In this study, we found co-differential genes between DKD and aging and established a diagnostic model of DKD based on these genes.

Methods

Differentially expressed genes (DEGs) in DKD were screened using GEO datasets. The intersection of the DEGs of DKD and aging-related genes revealed DKD and aging co-differential genes. Based on this, a genetic diagnostic model for DKD was constructed using LASSO regression. The characteristics of these genes were investigated using consensus clustering, WGCNA, functional enrichment, and immune cell infiltration. Finally, the expression of diagnostic model genes was analyzed using single-cell RNA sequencing (scRNA-seq) in DKD mice (model constructed by streptozotocin (STZ) injection and confirmed by tissue section staining).

Results

First, there were 159 common differential genes between DKD and aging, 15 of which were significant. These co-differential genes were involved in stress, glucolipid metabolism, and immunological functions. Second, a genetic diagnostic model (including IGF1, CETP, PCK1, FOS, and HSPA1A) was developed based on these genes. Validation of these model genes in scRNA-seq data revealed statistically significant variations in FOS, HSPA1A, and PCK1 gene expression between the early DKD and control groups. Validation of these model genes in the kidneys of DKD mice revealed that Igf1, Fos, Pck1, and Hspa1a had lower expression in DKD mice, with Igf1 expression being statistically significant.

Conclusion

Our findings suggest that DKD and aging co-differential genes are significant in DKD diagnosis, providing a theoretical basis for novel research directions on DKD.

The prevalence and associated risk factors of detectable renal morphological abnormalities in acromegaly

PURPOSE

The aim of this study was to investigate the prevalence of simple renal cysts (SRCs) and kidney stone disease (KSD) together with laboratory data in patients with acromegaly through comparisons with healthy subjects, and to examine the possible risk factors associated with these abnormalities in acromegaly.

METHODS

This retrospective, single-center study included 125 acromegaly patients (46.4 ± 11.6 years, 68 females/57 males) and 114 age-sex matched healthy individuals (45.3 ± 12.4 years, 59 females/55 males). Demographic data, clinical history, biochemical and abdominal/urinary system ultrasonographic data of the patients were reviewed.

RESULTS

The SRC prevalence (28.8% vs. 8.8%, p < 0.001) and the longitudinal and transverse lengths of kidneys (p < 0.05) were significantly higher in patients with acromegaly compared to the control group. The presence of acromegaly was determined to increase the risk of SRC formation 12.8-fold. The prevalence of KSD was similar in both the patient and control groups (15.2% vs. 7.9%, p = 0.08). Patients with acromegaly with renal cysts (n = 36) compared to the group without cysts (n = 89) were older, had a higher male gender frequency, a longer pre-diagnosis symptom duration, and a higher incidence of hypertension and diabetes mellitus at the time of diagnosis. The multivariate logistic regression analysis showed that only advanced age and male gender were associated risk factors for SRCs in acromegaly patients.

CONCLUSION

The results of this study showed that acromegaly disease significantly increased the prevalence of SRCs and kidney length compared to the age-sex matched healthy population, while the prevalence of KSD was similar. Advanced age and male gender were seen to be independent risk factors for SRC formation in patients with acromegaly.

The Beneficial Effects of Mesenchymal Stem Cells in Acute Kidney Injury: A Narrative Review

BACKGROUND

Acute kidney injury (AKI) is a multifaced disease characterized by a rapid decline in renal function. However, with growing insight into the pathophysiologic mechanisms of AKI, currently available interventions for AKI are merely supportive. Thus, novel therapies are urgently needed to improve the outcomes of patients with AKI. This narrative review aims to explore enhancing the beneficial effects of Mesenchymal Stem Cells(MSCs) in AKI.

METHODS

The authors examined all studies regarding the role of MSCs in AKI. And the authors undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question. The most relevant and up-to-date research was included.

RESULTS AND DISCUSSION

Based on encouraging preclinical results, stem cell therapy has been widely explored over the last decade. Among the various stem cell types investigated, mesenchymal stem cells are being intensely investigated by virtue of their numerous strengths, such as easy derivation, undemanding cell culture conditions, anti-apoptosis, immunomodulation, and anti-inflammation effects. Mounting evidence suggests that MSCs hold great potential in accelerating kidney repair following AKI in various preclinical models. Unfortunately, low engrafting efficiency and poor survival rate of injected MSCs in the injured renal tissue are major obstacles MSCs clinical application faces.

CONCLUSION

Various strategies, including genetic manipulation, mimicking the cellular microenvironment with different culture conditions, optimizing MSCs preparation and administration schedule, and screening patients who may more like benefit from MSCs therapy, have been developed to enhance the therapeutic potential of MSCs in AKI.

Acromegalic Cardiomyopathy: An Entity on its own? The Effects of GH and IGF-I Excess and Treatment on Cardiovascular Risk Factors

Acromegaly is a chronic disease resulting from constantly elevated concentrations of growth hormone (GH) and insulin-like growth factor I (IGF-I). If not adequately treated, GH and IGF-I excess is associated with various cardiovascular risk factors. These symptoms mainly include hypertension and impaired glucose metabolism, which can be observed in approximately one-third of patients. Other comorbidities are dyslipidemia and the presence of obstructive sleep apnea syndrome. However, even in the absence of conventional cardiovascular risk factors, myocardial hypertrophy can occur, which reflects the impact of GH and IGF-I excess itself on the myocardium and is defined as acromegalic cardiomyopathy. Whereas previous echocardiography-based studies reported a high prevalence of cardiomyopathy, this prevalence is much lower in cardiac magnetic resonance imaging-based studies. Myocardial hypertrophy in acromegaly is due to a homogeneous increase in the intracellular myocardial mass and extracellular myocardial matrix and improves following successful treatment through intracellular changes. Intramyocardial water retention or ectopic lipid accumulation might not be of relevant concern. Successful treatment significantly improves myocardial morphology, as well as cardiovascular risk factors. In addition to GH/IGF-I-lowering therapy, the diagnosis and treatment of cardiovascular complications is crucial for the successful management of acromegaly.

Plasma protein signatures reflect systemic immunity and allograft function in kidney transplantation

Kidney transplantation causes large perturbations of the immune system. While many studies focus on the allograft, insights into systemic effects are largely missing. Here, we analyzed the systemic immune response in 3 cohorts of kidney transplanted patients. Using serum proteomics, laboratory values, mass cytometry, histological and clinical parameters, inter-patient heterogeneity was leveraged for multi-omic co-variation analysis. We identified circulating immune modules (CIM) that describe extra-renal signatures of co-regulated plasma proteins. CIM are present in nontransplanted controls, in transplant conditions and during rejection. They are enriched in pathways linked to kidney function, extracellular matrix, signaling, and cellular activation. A complex leukocyte response in the blood during allograft quiescence and rejection is associated with CIM activity and CIM-specific cytokines. CIM activity correlates with kidney function including a 2-month prediction. Together, the data suggest a systemic and multi-layered response of transplant immunity that might be insightful for understanding allograft dysfunction and developing translational biomarkers.

Position statement on the diagnosis and management of acromegaly: The French National Diagnosis and Treatment Protocol (NDTP)

Acromegaly is a rare disease with prevalence of approximately 60 cases per million, slight female predominance and peak onset in adults in the fourth decade. Clinical diagnosis is often delayed by several years due to the slowly progressive onset of symptoms. There are multiple clinical criteria that define acromegaly: dysmorphic syndrome of insidious onset, symptoms related to the pituitary tumor (headaches, visual disorders), general signs (sweating, carpal tunnel syndrome, joint pain, etc.), complications of the disease (musculoskeletal, cardiovascular, pneumological, dental, metabolic comorbidities, thyroid nodules, colonic polyps, etc.) or sometimes clinical signs of associated prolactin hypersecretion (erectile dysfunction in men or cycle disorder in women) or concomitant mass-induced hypopituitarism (fatigue and other symptoms related to pituitary hormone deficiencies). Biological confirmation is based initially on elevated IGF-I and lack of GH suppression on oral glucose tolerance test or an elevated mean GH on repeated measurements. In confirmed cases, imaging by pituitary MRI identifies the causal tumor, to best determine management. In a minority of cases, acromegaly can be linked to a genetic predisposition, especially when it occurs at a young age or in a familial context. The first-line treatment is most often surgical removal of the somatotroph pituitary tumor, either immediately or after transient medical treatment. Medical treatments are most often proposed in patients not controlled by surgical removal. Conformal or stereotactic radiotherapy may be discussed on a case-by-case basis, especially in case of drug inefficacy or poor tolerance. Acromegaly should be managed by a multidisciplinary team, preferably within an expert center such as a reference or skill center for rare pituitary diseases.

A cohort study found a high risk of end-stage kidney disease associated with acromegaly

Acromegaly is a chronic systemic disease caused by excess levels of growth hormone and insulin-like growth factor-1 and is associated with numerous complications. Significantly, there is a lack of longitudinal data on kidney complications in patients with acromegaly. As such, we investigated the risk of end-stage kidney disease (ESKD) (stage 5D, 5T) in these patients with nationwide data obtained from the National Health Information Database of the National Health Insurance Service in Republic of Korea. A retrospective cohort study was conducted of 2.187 patients with acromegaly and 10,935 age- and sex-matched (1:5) control subjects without acromegaly over a mean follow-up period of 6.51 years. The study outcomes were analyzed using Cox proportional hazards regression analysis controlling for age, sex, household income, residential area, type 2 diabetes, hypertension, dyslipidemia, urolithiasis, congestive heart failure, myocardial infarction, stroke, and atrial fibrillation. The incidence (per 1,000 person-years) ESKD was 2.00 among patients with acromegaly but only 0.46 among controls, (hazard ratio 4.35 (95% confidence interval 2.63-7.20)) implicating a significantly higher risk. After adjustment for covariates, the risk of ESKD (2.36 (1.36-4.12)) was still significantly higher in patients with acromegaly than that in controls. Among the covariates, diabetes and hypertension were significant facilitators between acromegaly and ESKD in mediation analysis. Pituitary surgery and somatostatin analogues did not significantly change these associations. Thus, acromegaly may be linked with a higher risk for ESKD both independently and through mediators such as diabetes and hypertension.

The Long-Term Effect of Maternal Iron Levels in the Second Trimester on Mild Thinness among Preschoolers: The Modifying Effect of Small for Gestational Age

The supplementation of multiple micronutrients throughout pregnancy can reduce the risk of adverse birth outcomes and various diseases in children. However, the long-term effect of maternal multiple micronutrient levels in the second trimester on the overall development of preschoolers remains unknown. Therefore, 1017 singleton mother-infant pairs and 6-year-old preschoolers were recruited based on the China-Wuxi Birth Cohort Study. Meanwhile, information on the demographic characteristics of pregnant women and preschoolers, maternal copper, calcium, iron, magnesium, and zinc levels in whole blood during the second trimester, and neonatal outcomes, were collected. We aimed to investigate the long-term impact of maternal copper, calcium, iron, magnesium, and zinc levels in the second trimester on mild thinness among 6-year-old preschoolers, and the modifying effect of small for gestational age (SGA), within the Chinese population. Multiple logistic regression models revealed that high-level maternal iron in the second trimester reduced the risk of mild thinness [adjusted OR: 0.46 (95% CI: 0.26, 0.80)] among 6-year-old preschoolers. However, no significant association was found for the remaining four maternal essential metal elements. Additionally, the restricted cubic spline function showed that the risk of mild thinness decreased when maternal iron concentration exceeded 7.47 mmol/L in whole blood during the second trimester. Furthermore, subgroup analysis indicated that the long-term protective effect of high-level maternal iron on mild thinness was only observed in SGA infants. Summarily, high-level maternal iron in the second trimester distinctly lowers the risk of mild thinness among 6-year-old preschoolers, especially in preschoolers with birth outcomes of SGA. Our findings offer evidence for the implementation of iron supplementation in the second trimester as a preventive measure against mild thinness in children.

The regulation of human organic anion transporter 4 by insulin-like growth factor 1 and protein kinase B signaling

Human organic anion transporter 4 (hOAT4), mainly expressed in the kidney and placenta, is essential for the disposition of numerous drugs, toxins, and endogenous substances. Insulin-like growth factor 1 (IGF-1) is a hormone generated in the liver and plays important roles in systemic growth, development, and metabolism. In the current study, we explored the regulatory effects of IGF-1 and downstream signaling on the transport activity, protein expression, and SUMOylation of hOAT4. We showed that IGF-1 significantly increased the transport activity, expression, and maximal transport velocity Vmax of hOAT4 in kidney-derived cells. This stimulatory effect of IGF-1 on hOAT4 activity was also confirmed in cells derived from the human placenta. The increased activity and expression were correlated well with the reduced degradation rate of hOAT4 at the cell surface. Furthermore, IGF-1 significantly increased hOAT4 SUMOylation, and protein kinase B (PKB)-specific inhibitors blocked the IGF-1-induced regulations on hOAT4. In conclusion, our study demonstrates that the hepatic hormone IGF-1 regulates hOAT4 expressed in the kidney and placenta through the PKB signaling pathway. Our results support the remote sensing and signaling theory, where OATs play a central role in the remote communications among distal tissues.

Skeletal complications in acromegaly

Hypersecretion of growth hormone (GH) is rare and typically results from a pituitary functional tumor - somatotropinoma. It leads to excessive linear bone growth and manifests as gigantism if occurring in childhood and adolescence, before the closure of epiphyses or as a acromegaly in adulthood. The excess of GH impacts bone metabolism directly as well as indirectly through increased insulin-like growth factor 1 (IGF-1). In acromegaly as a consequence of overproduction of GH and IFG-1 and the influence of these hormones on bone osteoblasts, bone metabolism, growth and density increase. However, bone turnover is accelerated causing impaired bone microstructure and strength, which may lead to increased risk of vertebral fractures irrespective of normal bone mineral density. Apart from the changes in bone architecture, acromegaly also results in a degenerative joint disease of a different nature than primary osteoarthritis. Moreover, acromegaly leads to cardiovascular, metabolic and respiratory complications, and thus significantly impairs the quality of life. In this review, authors summarize the pathophysiology, diagnosis, and treatment of bone and joint disease in acromegaly.

Age, body composition parameters and glycaemic control contribute to trabecular bone score deterioration in acromegaly more than disease activity

Introduction

Impairment of bone structure in patients with acromegaly (AP) varies independently of bone mineral density (BMD). Body composition parameters, which are altered in patients with acromegaly, are important determinants of bone strength.

Purpose

The aim of this study was to examine BMD and lumbar trabecular bone score (TBS) by dual-energy X-ray absorptiometry (DXA) and to assess its relationship with disease activity, age, glucose metabolism, and body composition parameters.

Methods

This cross-sectional prospective study involved 115 patients with acromegaly (70 F, 45 M) and 78 healthy controls (CON) (53 F, 25 M) matched for age, gender, and BMI. Bone mineral density, TBS and body composition parameters were measured using DXA.

Results

AP presented with lower TBS compared to CON (1.2 ± 0.1 v 1.31 ± 0.1, P< 0.001). No significant correlation was observed between IGF-1/GH levels and TBS. Age, glycated haemoglobin, BMI, waist circumference, fat mass, and lean mass negatively correlated with TBS in both sexes. Multiple linear regression analysis of all these parameters revealed age and waist circumference as independent significant predictors of TBS in AP. We did not find difference in BMD (lumbar and femoral sites) between AP and CON nor between active and controlled AP. We observed negative correlation between age and BMD of the femoral neck and total hip (P < 0.001). Testosterone levels in males, BMI, waist circumference, fat mass, and lean mass positively correlated with BMD in AP, with stronger correlation between lean mass and BMD compared to fat mass.

Conclusion

Patients with acromegaly have lower TBS than controls, confirming impaired bone microarchitecture in acromegaly regardless of BMD. Age, body composition parameters and glucose metabolism contribute to TBS deterioration in AP more than disease activity itself.

Increase in intracellular and extracellular myocardial mass in patients with acromegaly: a cardiac magnetic resonance imaging study

BACKGROUND

Acromegaly is associated with an increased left ventricular (LV) mass, as reported in echo-based and, more recently, in a few cardiac magnetic resonance imaging (MRI) studies. One possible explanation for this increased LV mass could be water retention and subsequent myocardial edema.

METHODS

In this prospective cross-sectional study, 26 patients with active acromegaly before and after treatment and 31 controls of comparable age and sex were investigated using cardiac MRI. Cardiac morphology, function, and myocardial tissue characteristics were evaluated. Myocardial T2 relaxation time was used as the main outcome measure of myocardial edema. The study was registered with clinicaltrials.gov (NCT02948322).

RESULTS

Patients compared to controls had greater LV mass indexes (58.1 [54.7-68.6] vs 46.0 [41.3-49.8] g/m2; P < .001) and end-diastolic volume (EDV) indexes (97.3 [88-101.2] vs 81.6 [78.1-96.2] mL/m2; P = .0069) and had comparable global contractile function. T2 values were not different between patients and controls. Both intracellular (43.83 [41.0-50.0] vs 34.32 [28.9-38.7] g/m2; P < .001) and extracellular (15.06 [13.5-17.1] vs 11.6 [10.8-12.7] g/m2; P < .001) LV mass indexes were higher in patients compared to controls. Log growth hormone correlated with myocardial mass (r = 0.75; P < .001). Sex, systolic blood pressure (BP), and the presence of acromegaly were predictors of the LV mass index. The extracellular LV mass index was associated with sex and the presence of acromegaly, whereas the intracellular LV mass index was associated with sex, systolic BP, and high-density lipoprotein (HDL) cholesterol. Acromegaly treatment reduced EDV and total and intracellular LV mass indexes without significantly affecting extracellular mass.

CONCLUSION

Acromegaly results in a disease-specific form of LV hypertrophic remodeling, characterized by an increase in both intra- and extracellular mass. The LV mass index and intracellular mass were decreased by treatment.

Reporting a novel growth hormone receptor gene variant in an Iranian consanguineous pedigree with Laron syndrome: a case report

BACKGROUND

Human growth hormone (hGH) plays a crucial role in growth by binding to growth hormone receptor (GHR) in target cells. Binding of GH molecules to their cognate receptors triggers downstream signaling pathways leading to the transcription of several genes, including insulin-like growth factor (IGF)-1. Pathogenic variants in the GHR gene can result in structural and functional defects in the GHR protein, leading to Laron Syndrome (LS) with the primary clinical manifestation of short stature. So far, around 100 GHR variants have been reported, mostly biallelic, as causing LS.

CASE PRESENTATION

We report on three siblings from an Iranian consanguineous family who presented with dwarfism. Whole-exome sequencing (WES) was performed on the proband, revealing a novel homozygous missense variant in the GHR gene (NM_000163.5; c.610 T > A, p.(Trp204Arg)) classified as a likely pathogenic variant according to the recommendation of the American College of Medical Genetics (ACMG). Co-segregation analysis was investigated using Sanger sequencing.

CONCLUSIONS

To date, approximately 400-500 LS cases with GHR biallelic variants, out of them 10 patients originating from Iran, have been described in the literature. Given the high rate of consanguineous marriages in the Iranian population, the frequency of LS is expected to be higher, which might be explained by undiagnosed cases. Early diagnosis of LS is very important, as treatment is available for this condition.

Insulin growth factor axis and cardio-renal risk in diabetic kidney disease: an analysis from the CREDENCE trial

BACKGROUND

The insulin-like growth factors (IGF) play a crucial role in regulating cellular proliferation, apoptosis, and key metabolic pathways. The ratio of IGF-1 to IGF binding protein-3 (IGFBP-3) is an important factor in determining IGF-1 bioactivity. We sought to investigate the association of IGF-1 and IGFBP-3 with cardio-renal outcomes among persons with type 2 diabetes.

METHODS

Samples were available from 2627 individuals with type 2 diabetes and chronic kidney disease that were randomized to receive canagliflozin or placebo and were followed up for incident cardio-renal events. Primary outcome was defined as a composite of end-stage kidney disease, doubling of the serum creatinine level, or renal/cardiovascular death. IGF-1 and IGFBP-3 were measured at baseline, Year-1 and Year-3. Elevated IGF-1 level was defined according to age-specific cutoffs. Cox proportional hazard regression was used to investigate the association between IGF-1 level, IGFBP-3, and the ratio of IGF-1/IGFBP-3 with clinical outcomes.

RESULTS

Elevated IGF-1 was associated with lower glomerular filtration rate at baseline. Treatment with canagliflozin did not significantly change IGF-1 and IGFBP-3 concentrations by 3 years (p-value > 0.05). In multivariable models, elevated IGF-1 (above vs below age-specific cutoffs) was associated with the primary composite outcome (incidence rate:17.8% vs. 12.7% with a hazard ratio [HR]: 1.52; 95% confidence interval CI 1.09-2.13;P: 0.01), renal composite outcome (HR: 1.65; 95% CI 1.14-2.41; P: 0.01), and all-cause mortality (HR: 1.52; 95% CI 1.00-2.32; P; 0.05). Elevations in log IGFBP-3 did not associate with any clinical outcomes. Increase in log IGF-1/IGFBP-3 ratio was also associated with a higher risk of the primary composite outcome (HR per unit increase: 1.57; 95% CI 1.09-2.26; P; 0.01).

CONCLUSIONS

These results further suggest potential importance of IGF biology in the risk for cardio-renal outcomes in type 2 diabetes. SGLT2 inhibition has no impact on the biology of IGF despite its significant influence on outcomes.

TRIAL REGISTRATION

CREDENCE; ClinicalTrials.gov Identifier: NCT02065791.

Sex Differences in Long-Term Safety and Tolerability of GH Replacement Therapy in GH Deficient Adults

CONTEXT

Previous studies report that outcomes of growth hormone (GH) replacement therapy (GHRT) might be less beneficial in growth hormone deficient (GHD) women compared with men.

OBJECTIVE

This study investigated possible contributing factors regarding this previously found sex difference.

METHODS

This retrospective cohort study, conducted at a nationwide outpatient clinic (the Dutch National Registry of GH Treatment in Adults), included Dutch adult GHD men (n = 1335) and women (n = 1251) treated with GHRT. The patients' baseline characteristics, details of GHRT, and the tolerability and long-term safety of GHRT were measured.

RESULTS

During treatment, sensitivity analysis showed that insulin-like growth factor-1 (IGF-1) SD scores remained subnormal more often in women (P < 0.001), while scores above normal were more frequent in men (P < 0.001). Women reported more adverse events (P < 0.001), especially symptoms related to fluid retention, and more often needed a dose reduction or temporary stop of GHRT (P = 0.001). In percentages, both sexes equally discontinued GHRT, as was also true for the risk in developing type 2 diabetes mellitus, benign neoplasms, and tumor recurrence. The risk of developing malignant neoplasms was higher in men (P = 0.012).

CONCLUSION

Data obtained from the Dutch National Registry of GH Treatment in Adults indicate that GHD women might be treated suboptimally, reflected as lower IGF-1 status and lower GHRT tolerability, leading to more frequent changes in treatment regimen but not discontinuation of GHRT. Regarding long-term safety, we found a higher risk for development of malignancies in GHD men.

Causal associations between insulin-like growth factor 1 and vitamin D levels: a two-sample bidirectional Mendelian randomization study

Background

Insulin-like growth factor 1 (IGF-1) plays a vital role in the attainment and maintenance of bone mass throughout life and is closely related to the stature of children. 25-Hydroxyvitamin D (25-OHD) is an intermediate of vitamin D (Vit D) metabolism and a key indicator of Vit D nutritional status. Multiple studies have revealed that IGF-1 levels undergo a non-significant increase after Vit D supplementation. Here, we analyzed the causal and reverse causal relationships between 25-OHD and IGF-1 levels using Mendelian randomization (MR).

Methods

Two-sample MR was used to estimate an unconfounded bidirectional causal relationship between the level of IGF-1 and those of Vit D and 25-OHD. Single nucleotide polymorphisms (SNPs) were filtered from genome-wide association studies (GWAS) after a comprehensive search of the Integrative Epidemiology Unit GWAS database. Several MR methods were employed, including inverse-variance weighted (IVW) method, and a sensitivity analysis was undertaken to detect whether pleiotropy or heterogeneity biased the MR results.

Results

Genetically predicted IGF-1 was found to have a causal association with Vit D and serum 25-OHD levels, where Vit D and serum 25-OHD levels increased with increasing IGF-1 concentrations (Vit D: IVW β:0.021, 95% CI: 0.005-0.036, p = 7.74 × 10^-3; 25-OHD: IVW β: 0.041, 95% CI: 0.026-0.057, p = 2.50 × 10^-7). A reverse causal effect was also found, indicating Vit D and serum 25-OHD have a positive causal relationship with IGF-1 (Vit D: IVW β:0.182, 95% CI: 0.061-0.305, p = 3.25 × 10^-3; 25-OHD: IVW β: 0.057, 95% CI = 0.017-0.096, p = 4.73 × 10^-3). The sensitivity analysis showed that horizontal pleiotropy was unlikely to bias the causality in this study (MR-Egger: Vit D intercept p = 5.1 × 10^-5, 25-OHD intercept p = 6.4 × 10^-4 in forward analysis; Vit D intercept p = 6.6 × 10^-4, 25-OHD intercept p = 1.9 × 10^-3 in reverse analysis), and a leave-one-out analysis did not identify evidence of bias in the results.

Conclusion

The results of the MR analysis provide evidence that IGF-1 has positive causal and reverse causal relationships with Vit D and serum 25-OHD, respectively, in European populations. Our findings also provide guidance for the prevention and treatment of short stature and other related diseases.

The Role of Insulin-like Growth Factor-1 and Its Receptor in the Eye: A Review and Implications for IGF-1R Inhibition

PURPOSE

FDA approval of teprotumumab for thyroid eye disease in January 2020 reinforced interest in the pharmacologic potential of insulin-like growth factor-1 (IGF-1) and its receptor, IGF-1R. Despite recent approval and adaptation for ophthalmic use, IGF-1R inhibitors are not a new therapeutic class. In 1986, Yamashita described aIR3, a monoclonal antibody to IGF-1R (anti-IGF-1R), that inhibited the effect of IGF-1 on growth hormone release. Given the widespread presence of IGF-1R, interrupting this receptor can lead to systemic physiologic effects, some adverse. We aim to review what is known about IGF-1/IGF-1R in the eye and consider the possible local side effects, unintended consequences, and potential uses of this medication class.

METHODS

A PubMed database search utilizing the keywords "insulin-like growth factor-1, eye, inhibitor, antibody, side effect" was performed to identify publications discussing IGF-1 in the human eye from January 2011 to August 2021. Criteria for acceptance included studies discussing human subjects or human tissue specifically related to the eye.

RESULTS

Out of a total of 230 articles, 47 were organized in 3 subject groups for discussion: thyroid-associated orbitopathy, cornea and the ocular surface, and the retina and neovascularization. Review of the literature demonstrated that IGF-1 affects growth and development of the eye, epithelial proliferation, retinal angiogenesis, inflammation, and is associated with thyroid-associated orbitopathy.

CONCLUSIONS

IGF-1R exists throughout in the human body, including the cornea, retina, and orbit. Research regarding ocular effects of IGF-1/IGF-1R outside thyroid eye disease is limited. Carefully designed studies and clinical assessments of patients undergoing treatment with anti-IGF-1R may identify ocular side effects and foster consideration of the role of anti-IGF-1R in ocular therapeutics. Given the increasing use of anti-IGF-1R antibodies, understanding their ocular effects, side effects, and potential systemic implications for use in disease is critical.

Clinical Biology of the Pituitary Adenoma

All endocrine glands are susceptible to neoplastic growth, yet the health consequences of these neoplasms differ between endocrine tissues. Pituitary neoplasms are highly prevalent and overwhelmingly benign, exhibiting a spectrum of diverse behaviors and impact on health. To understand the clinical biology of these common yet often innocuous neoplasms, we review pituitary physiology and adenoma epidemiology, pathophysiology, behavior, and clinical consequences. The anterior pituitary develops in response to a range of complex brain signals integrating with intrinsic ectodermal cell transcriptional events that together determine gland growth, cell type differentiation, and hormonal production, in turn maintaining optimal endocrine health. Pituitary adenomas occur in 10% of the population; however, the overwhelming majority remain harmless during life. Triggered by somatic or germline mutations, disease-causing adenomas manifest pathogenic mechanisms that disrupt intrapituitary signaling to promote benign cell proliferation associated with chromosomal instability. Cellular senescence acts as a mechanistic buffer protecting against malignant transformation, an extremely rare event. It is estimated that fewer than one-thousandth of all pituitary adenomas cause clinically significant disease. Adenomas variably and adversely affect morbidity and mortality depending on cell type, hormone secretory activity, and growth behavior. For most clinically apparent adenomas, multimodal therapy controlling hormone secretion and adenoma growth lead to improved quality of life and normalized mortality. The clinical biology of pituitary adenomas, and particularly their benign nature, stands in marked contrast to other tumors of the endocrine system, such as thyroid and neuroendocrine tumors.

Covert actions of growth hormone: fibrosis, cardiovascular diseases and cancer

Since its discovery nearly a century ago, over 100,000 studies of growth hormone (GH) have investigated its structure, how it interacts with the GH receptor and its multiple actions. These include effects on growth, substrate metabolism, body composition, bone mineral density, the cardiovascular system and brain function, among many others. Recombinant human GH is approved for use to promote growth in children with GH deficiency (GHD), along with several additional clinical indications. Studies of humans and animals with altered levels of GH, from complete or partial GHD to GH excess, have revealed several covert or hidden actions of GH, such as effects on fibrosis, cardiovascular function and cancer. In this Review, we do not concentrate on the classic and controversial indications for GH therapy, nor do we cover all covert actions of GH. Instead, we stress the importance of the relationship between GH and fibrosis, and how fibrosis (or lack thereof) might be an emerging factor in both cardiovascular and cancer pathologies. We highlight clinical data from patients with acromegaly or GHD, alongside data from cellular and animal studies, to reveal novel phenotypes and molecular pathways responsible for these actions of GH in fibrosis, cardiovascular function and cancer.

Increased activity of the metalloproteinase PAPP-A promotes diabetes-induced glomerular hypertrophy

BACKGROUND

Diabetic nephropathy (DN) is a serious complication of diabetes and a common cause of end stage renal failure. Insulin-like growth factor (IGF)-signaling has been implicated in DN, but is mechanistically poorly understood. Here, we assessed the activity of the metalloproteinase PAPP-A, an activator of IGF activity, and its possible interaction with the endogenous PAPP-A inhibitors stanniocalcin (STC)-1 and -2 in the mammalian kidney under normal and hyperglycemic conditions.

METHODS AND RESULTS

Immunohistochemistry demonstrated that PAPP-A, its proteolytic substrate IGF binding protein-4, STC1 and STC2 are present in the human kidney. Endogenous inhibited complexes of PAPP-A (PAPP-A:STC1 and PAPP-A:STC2) were demonstrated in media conditioned by human mesangial cells (HMCs), suggesting that PAPP-A activity is regulated by the STCs in kidney tissue. A method for the selective detection of active PAPP-A in tissue was developed and a significant increase in glomerular active PAPP-A in human diabetic kidney relative to normal was observed. In DN patients, the estimated glomerular filtration rate correlated with PAPP-A activity. In diabetic mice, glomerular growth was reduced when PAPP-A activity was antagonized by adeno-associated virus-mediated overexpression of STC2.

CONCLUSION

We propose that PAPP-A activity in renal tissue is precisely balanced by STC1 and STC2. An imbalance in this equilibrium causing increased PAPP-A enzymatic activity potentially contributes to the development of DN, and thus, therapeutic targeting of PAPP-A activity may represent a novel strategy for its treatment.

Skeletal disorders associated with the growth hormone-insulin-like growth factor 1 axis

Growth hormone (GH) and insulin-like growth factor 1 (IGF1) are important regulators of bone remodelling and metabolism and have an essential role in the achievement and maintenance of bone mass throughout life. Evidence from animal models and human diseases shows that both GH deficiency (GHD) and excess are associated with changes in bone remodelling and cause profound alterations in bone microstructure. The consequence is an increased risk of fractures in individuals with GHD or acromegaly, a condition of GH excess. In addition, functional perturbations of the GH-IGF1 axis, encountered in individuals with anorexia nervosa and during ageing, result in skeletal fragility and osteoporosis. The effect of interventions used to treat GHD and acromegaly on the skeleton is variable and dependent on the duration of the disease, the pre-existing skeletal state, coexistent hormone alterations (such as those occurring in hypogonadism) and length of therapy. This variability could also reflect the irreversibility of the skeletal structural defect occurring during alterations of the GH-IGF1 axis. Moreover, the effects of the treatment of GHD and acromegaly on locally produced IGF1 and IGF binding proteins are uncertain and in need of further study. This Review highlights the pathophysiological, clinical and therapeutic aspects of skeletal fragility associated with perturbations in the GH-IGF1 axis.

Physiological aspects of pig kidney xenotransplantation and implications for management following transplant

Successful organ transplantation between species is now possible, using genetic modifications. This article aims to provide a comprehensive overview of the differences and similarities in kidney function between humans, primates, and pigs, in preparation for pig-allograft to human xenotransplantation. The kidney, as the principal defender of body homeostasis, acts as a sensor, effector, and regulator of physiologic feedback systems. Considerations are made for anticipated effects on each system when a pig kidney is placed into a human recipient. Discussion topics include anatomy, global kidney function, sodium and water handling, kidney hormone production and response to circulating hormones, acid-base balance, and calcium and phosphorus handling. Based on available data, pig kidneys are anticipated to be compatible with human physiology, despite a few barriers.

The biochemical diagnosis of acromegaly: revising the role of measurement of IGF-I and GH after glucose load in 5 questions

INTRODUCTION

Acromegaly is a rare disorder characterized by the excessive secretion of growth hormone (GH), mostly caused by pituitary adenomas. While in full-blown cases the diagnosis is easy to establish, milder cases are more challenging. Additionally, establishing whether full cure after surgery is reached may be difficult.

AREAS COVERED

In this article, we will review the challenges posed by the variability in measurements of GH and its main effector insulin-like growth factor I (IGF-I) due to both biological changes, co-morbidities, and assays variability.

EXPERT OPINION

Interpretation of GH and IGF-I assays is important in establishing an early diagnosis of acromegaly, in avoiding misdiagnosis, and in establishing if cure is achieved by surgery. Physicians should be familiar with the variables that affect measurements of these 2 hormones, and with the performance of the assays available in their practice.

Growth control of the kidney

The functional mass of kidney tissue in an adult is an important determinant of human health. Kidney formation during development is an essential determinant of the final nephron endowment of the adult organ, and no evidence has been reported that mice or humans are able to generate new nephrons after the developmental period. Mechanisms controlling organ growth after development are essential to establish the final adult organ size. The potential for organ growth is maintained in adult life and the size of one kidney may be significantly increased by loss of the contralateral kidney. The mouse has provided a model system for investigators to critically explore genetic, cell biological, and hormonal control of developmental and juvenile kidney growth. This article reviews three basic aspects of kidney size regulation: (1) Mechanisms that control nephron formation and how these are altered by the cessation of nephrogenesis at the end of the developmental period. (2) Applicability of the general model for growth hormone-insulin like growth factor control to kidney growth both pre- and postnatally. (3) Commonalities between mechanisms of juvenile kidney growth and the compensatory growth that is stimulated in adult life by reduction of kidney mass. Understanding the mechanisms that determine set-points for cell numbers and size in the kidney may inform ongoing efforts to generate kidney tissue from stem cells.

Dilated cardiomyopathy in a cat with congenital hyposomatotropism

Case summary

A 7-month-old domestic shorthair cat was presented for evaluation of stunted growth, recurrent hypoglycaemia during the first months of its life and altered mentation. Complete blood count and biochemistry were unremarkable, except for mildly elevated serum creatinine concentration (despite low muscle mass) and concurrent isosthenuria. Hyposomatotropism was diagnosed based on persistent low circulating insulin-like growth factor 1 concentrations and a lack of response of circulating growth hormone (GH) concentration after the administration of GH-releasing hormone. Other endocrinopathies such as hypothyroidism and hypoadrenocorticism were excluded. MRI of the brain revealed a fluid-filled empty sella tursica, consistent with a pituitary cyst and atrophy/hypoplasia of the pituitary. Echocardiography was unremarkable at the time of diagnosis of hyposomatotropism. Three months later, ovariohysterectomy revealed immature ovaries, raising the suspicion of luteinising and follicle-stimulating hormone deficiency. At 1 year of age, the cat developed congestive heart failure secondarily to dilated cardiomyopathy (DCM) with severely reduced left ventricular systolic function and died a few days later. Pathology showed atrophy of the adenohypophysis, epithelial delineation of the pituitary cysts, mild cardiomegaly, multifocal fibrosis of the left ventricle and a mild, multifocal, chronic epicarditis.

Relevance and novel information

GH deficiency is a very rare endocrinopathy in cats. This is the first case to describe the development of DCM with concurrent hyposomatotropism, which has previously been reported in human medicine. Other notable abnormalities that could be related to GH deficiency are juvenile self-limiting hypoglycaemia, behavioural changes and possible nephropathy.

Molecular methods for increasing the effectiveness of ovarian cancer treatment: a systematic review

Background: The aim of the current study is to analyze and summarize the latest research on improving therapy in ovarian cancer. Materials & methods: Data analysis was based on a review of publications from 2011 to 2021 in the PubMed database with use of the search terms including 'EGFR ovarian cancer', 'folate receptor inhibitors ovarian cancer', 'VEGF ovarian cancer', 'PDGF ovarian cancer' and 'CTLA-4 ovarian cancer'. Results: 6643 articles were found; 238 clinical trials and randomized control trials were analyzed; 122 studies were rejected due to inconsistency with the topic of the work. Conclusion: Extensive research on the treatment of ovarian cancer increases the chance of developing the most effective therapy suited to the individual needs of the patient.

Clinical outcome and gut development after insulin-like growth factor-1 supplementation to preterm pigs

BACKGROUND

Elevation of circulating insulin-like growth factor-1 (IGF-1) within normal physiological levels may alleviate several morbidities in preterm infants but safety and efficacy remain unclear. We hypothesized that IGF-1 supplementation during the first 1-2 weeks after preterm birth improves clinical outcomes and gut development, using preterm pigs as a model for infants.

METHODS

Preterm pigs were given vehicle or recombinant human IGF-1/binding protein-3 (rhIGF-1, 2.25 mg/kg/d) by subcutaneous injections for 8 days (Experiment 1, n = 34), or by systemic infusion for 4 days (Experiment 2, n = 19), before collection of blood and organs for analyses.

RESULTS

In both experiments, rhIGF-1 treatment increased plasma IGF-1 levels 3-4 fold, reaching the values reported for term suckling piglets. In Experiment 1, rhIGF-1 treatment increased spleen and intestinal weights without affecting clinical outcomes like growth, blood biochemistry (except increased sodium and gamma-glutamyltransferase levels), hematology (e.g., red and white blood cell populations), glucose homeostasis (e.g., basal and glucose-stimulated insulin and glucose levels) or systemic immunity variables (e.g., T cell subsets, neutrophil phagocytosis, LPS stimulation, bacterial translocation to bone marrow). The rhIGF-1 treatment increased gut protein synthesis (+11%, p < 0.05) and reduced the combined incidence of all-cause mortality and severe necrotizing enterocolitis (NEC, p < 0.05), but had limited effects on intestinal morphology, cell proliferation, cell apoptosis, brush-border enzyme activities, permeability and levels of cytokines (IL-1β, IL-6, IL-8). In Experiment 2, rhIGF-1 treated pigs had reduced blood creatine kinase, creatinine, potassium and aspartate aminotransferase levels, with no effects on organ weights (except increased spleen weight), blood chemistry values, clinical variables or NEC.

CONCLUSION

Physiological elevation of systemic IGF-1 levels for 8 days after preterm birth increased intestinal weight and protein synthesis, spleen weight and potential overall viability of pigs, without any apparent negative effects on recorded clinical parameters. The results add further preclinical support for safety and efficacy of supplemental IGF-1 to hospitalized very preterm infants.

Changes in Cross-Sectional Area of the Median Nerve and Body Composition Parameters after Treatment of Acromegaly: 1 year Follow-Up

OBJECTIVE

Median neuropathy is a common manifestation of acromegaly, although its pathology is uncertain. Changes in levels of growth hormone (GH) and insulin-like growth factor I (IGF-I) and body composition are potential parameters in pathology of median neuropathy in acromegaly. We aimed to assess changes in the cross-sectional area (CSA) of the median nerve and body composition in newly diagnosed acromegalic patients 1 year after treatment and to determine their mutual relationships.

DESIGN

This prospective study included 30 patients with newly diagnosed acromegaly and 30 healthy controls matched for age, gender, and body mass index. Physical and laboratory examinations, dual-energy X-ray absorptiometry (DXA), and ultrasound evaluations were performed at baseline and 1 year after initial treatment.

RESULTS

The CSA of the median nerve was increased in acromegalic patients compared with controls (13.1 mm² [12.2-14.9] vs 7.5 mm² [6.4-8.4], P < 0.001). One year after treatment of acromegaly, GH and IGF-I levels decreased significantly. The median nerve CSA was significantly reduced after treatment (11.6 mm² [10.2-13.1], P < 0.001). Reduction of IGF-I levels correlated with a decrease in lean mass and increase in fat mass. The median nerve CSA positively correlated with IGF-I levels (R = 0.492, P=0.006) and lean mass (R = 0.419, P=0.021) in acromegalic patients before treatment.

CONCLUSION

This study demonstrates a reduction in the median nerve CSA 1 year after treatment of acromegaly. These changes are closely associated with a reduction in IGF- I levels and in lean body mass. The enlargement of the median nerve in acromegaly can be reversed with adequate treatment.

Influence of Disease Activity and Body Composition Parameters on Cross-Sectional Area of the Median Nerve in Acromegalic Patients

Carpal tunnel syndrome (CTS) is neuropathy that occurs due to compression of the median nerve in the carpal tunnel. Acromegaly is one of the important causes of CTS. The aim of this study was to examine median nerve with ultrasound in acromegalic patients and to assess the relationship with activity, duration of disease and body composition parameters. We prospectively examined the cross-sectional area (CSA) of the median nerve with high-resolution ultrasound in 107 acromegalic patients – control group (70 females and 37 males) and 107 healthy controls (70 females and 37 males) matched for age, gender, and BMI. Body composition parameters were assessed by dual-energy X-ray absorptiometry (DXA). The Student t-tests and Pearson correlation were used for data analysis. The cross sectional area of the median nerve was increased in acromegalic patients compared to controls (11.9±4.8 mm2 vs. 7.7±2.4 mm2, P<0.001). Positive correlation was found between IGF-1 levels and CSA in the acromegalic group (R = 0.400, P<0.001). Relationship between CSA and duration of acromegaly was not confirmed. In acromegalic patients, BMI correlated with the CSA (R=0.294, P=0.002). There was no significant difference in BMI, fat mass between the acromegalic and control group, but lean mass was higher in acromegalic patients compared with controls (54.8±13.3 vs. 51±11.6, P=0.047). Lean mass and LMI (total body lean mass/height) positively correlated with CSA in acromegalic patients (R=0.340, P<0.001; R=0.424, P<0.001). No correlation was observed between fat mass and CSA of median nerve in all groups. We confirmed the enlargement of the median nerve in acromegalic patients. This enlargement is proportional to the degree of IGF-1 levels and is not dependent on the duration of the disease. The enlargement of the median nerve in acromegalic patients also depends on lean body mass and is not dependent on fat body mass.

[Discordant parameters of insulin-like growth factor 1 and growth hormone in the diagnosis and monitoring of acromegaly]

Acromegaly is a rare endocrine disorder associated with multiple complications and increased mortality. Timely diagnosis and adequate treatment can bring the life expectancy of patients with acromegaly closer to the general population level. The tests for the diagnosis of acromegaly are measurement of both serum GH, and GH after oral glucose administration; serum insulin-like growth factor-1 (IGF-1). However, in clinical practice, up to 39% of patients with discordant results are found. The patients with discordant GH and IGF-1levels, are the most difficult to manage. This review discusses the prevalence of discordant GH and IGF-1 outcomes in patients with acromegaly; factors causing this discrepancy; the impact of hormone levels on treatment outcomes. Although endocrinologists are used to dealing with this discrepancy in clinical practice for many years, discordant patients'outcome remains uncertain and undefined The optimal treatment should be individually tailored for each patient, taking into account all clinical parameters.

Effects of hormonal changes on sarcopenia in chronic kidney disease: where are we now and what can we do?

Sarcopenia or muscle wasting is a progressive and generalized skeletal muscle disorder involving the accelerated loss of muscle mass and function, often associated with muscle weakness (dynapenia) and frailty. Whereas primary sarcopenia is related to ageing, secondary sarcopenia happens independent of age in the context of chronic disease states such as chronic kidney disease (CKD). Sarcopenia has become a major focus of research and public policy debate due to its impact on patient's health-related quality of life, health-care expenditure, morbidity, and mortality. The development of sarcopenia in patients with CKD is multifactorial and it may occur independently of weight loss or cachexia including under obese sarcopenia. Hormonal imbalances can facilitate the development of sarcopenia in the general population and is a common finding in CKD. Hormones that may influence the development of sarcopenia are testosterone, growth hormone, insulin, thyroid hormones, and vitamin D. Although the relationship between free testosterone level that is low in uraemic patients and sarcopenia in CKD is not well-defined, functional improvement may be seen. Unlike testosterone, it is known that vitamin D is associated with muscle strength, muscle size, and physical performance in patients with CKD. Outcomes after vitamin D replacement therapy are still controversial. The half-life of growth hormone (GH) is prolonged in patients with CKD. Besides, IGF-1 levels are normal in patients with Stage 4 CKD-a minimal reduction is seen in the end-stage renal disease. Unresponsiveness or resistance of IGF-1 and changes in the GH/IGF-1 axis are the main causes of sarcopenia in CKD. Low serum T3 level is frequent in CKD, but the net effect on sarcopenia is not well-studied. CKD patients develop insulin resistance (IR) from the earliest period even before GFR decline begins. IR reduces glucose utilization as an energy source by hepatic gluconeogenesis, decreasing muscle glucose uptake, impairing intracellular glucose metabolism. This cascade results in muscle protein breakdown. IR and sarcopenia might also be a new pathway for targeting. Ghrelin, oestrogen, cortisol, and dehydroepiandrosterone may be other players in the setting of sarcopenia. In this review, we mainly examine the effects of hormonal changes on the occurrence of sarcopenia in patients with CKD via the available data.

Growth Hormone and IGF1 Actions in Kidney Development and Function

Growth hormone (GH) exerts multiple effects on different organs including the kidneys, either directly or via its main mediator, insulin-like-growth factor-1 (IGF-1). The GH/IGF1 system plays a key role in normal kidney development, glomerular hemodynamic regulation, as well as tubular water, sodium, phosphate, and calcium handling. Transgenic animal models demonstrated that GH excess (and not IGF1) may lead to hyperfiltration, albuminuria, and glomerulosclerosis. GH and IGF-1 play a significant role in the early development of diabetic nephropathy, as well as in compensatory kidney hypertrophy after unilateral nephrectomy. Chronic kidney disease (CKD) and its complications in children are associated with alterations in the GH/IGF1 axis, including growth retardation, related to a GH-resistant state, attributed to impaired kidney postreceptor GH-signaling and chronic inflammation. This may explain the safety of prolonged rhGH-treatment of short stature in CKD.

Incidence of Benign and Malignant Tumors in Patients With Acromegaly Is Increased: A Nationwide Population-based Study

CONTEXT

Whether cancer risk in acromegaly is increased remains controversial, and the risk of benign tumors has been little studied.

OBJECTIVE

To investigate the incidence of benign and malignant tumors in acromegaly in a nationwide population-based study.

METHODS

Adult patients diagnosed with acromegaly between 1987 and 2017 were identified in the Swedish National Patient Registry. The diagnoses of benign and malignant tumors were recorded. Standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) for neoplasms with 95% CIs were calculated using the Swedish general population as reference.

RESULTS

The study included 1296 patients (52% women). Mean (SD) age at diagnosis was 51.6 (14.7) years. Median (range) follow-up time was 11.7 (0-31) years. Overall, 186 malignancies were identified in acromegalic patients compared with 144 expected in the general population (SIR 1.3; 95% CI 1.1-1.5). The incidence of colorectal and anal cancer (SIR 1.5; 95% CI 1.0-2.2), and renal and ureteral cancer (SIR 4.0; 95% CI 2.3-6.5) was increased, whereas the incidence of malignancies of the respiratory system, brain, prostate, and breast was not. Only 3 cases of thyroid cancer were recorded. Mortality due to malignancies was not increased (SMR 1.1; 95% CI 0.9-1.4). Incidence of benign tumors was increased more than 2-fold (SIR 2.4; 95% CI 2.1-2.7).

CONCLUSION

Patients with acromegaly had an increased risk of both benign and malignant tumors, including colorectal and anal cancer, and renal and ureteral cancer. Whether this is associated with acromegaly itself or due to more intensive medical surveillance remains to be shown.

Influence of Disease Activity and Body Composition Parameters on Cross-Sectional Area of the Median Nerve in Acromegalic Patients

Carpal tunnel syndrome (CTS) is neuropathy that occurs due to compression of the median nerve in the carpal tunnel. Acromegaly is one of the important causes of CTS. The aim of this study was to examine median nerve with ultrasound in acromegalic patients and to assess the relationship with activity, duration of disease and body composition parameters. We prospectively examined the cross-sectional area (CSA) of the median nerve with high-resolution ultrasound in 107 acromegalic patients (70 females and 37 males) and 107 healthy controls (70 females and 37 males) matched for age, gender, and BMI. Body composition parameters were assessed by dual-energy X-ray absorptiometry (DXA). The Student t-tests and Pearson correlation were used for data analysis. The cross sectional area of the median nerve was increased in acromegalic patients compared to controls (11.9 ± 4.8 mm2 vs. 7.7 ± 2.4 mm2, P < 0.001). Positive correlation was found between IGF-1 levels and CSA in the acromegalic group (R = 0.400, P < 0.001). Relationship between CSA and duration of acromegaly was not confirmed. In acromegalic patients, BMI correlated with the CSA (R = 0.294, P = 0.002). There was no significant difference in BMI, fat mass between the acromegalic and control group, but lean mass was higher in acromegalic patients compared with controls (54.8 ± 13.3 vs. 51 ± 11.6, P = 0.047). Lean mass and LMI (total body lean mass/height) positively correlated with CSA in acromegalic patients (R = 0.340, P < 0.001; R = 0.424, P < 0.001). No correlation was observed between fat mass and CSA of median nerve in either group. We confirmed the enlargement of the median nerve in acromegalic patients. This enlargement is proportional to the degree of IGF-1 levels and is not dependent on the duration of the disease. The enlargement of the median nerve in acromegalic patients also depends on lean body mass and is not dependent on fat body mass.

Biochemical assessment of phosphate homeostasis

Phosphate homeostasis is a requirement for normal life. Phosphate is involved in the synthesis of membrane lipids, DNA, RNA, and energy-rich molecules (ATP and GTP), and the regulation of protein activity by phosphorylation/dephosphorylation. Moreover, phosphate is a component of apatite crystals, which provide stability to the bone, and is essential for normal growth. Phosphate balance in the body is the difference between net phosphate absorption through the intestine and phosphate excretion through the kidney. Numerous disorders, both genetic and acquired, may alter phosphate homeostasis. In affected individuals, it is crucial to identify the underlying mechanism(s) to provide adequate treatment; however, phosphate homeostasis assessment remains challenging. Besides the measurement of key hormones involved in the control of phosphate homeostasis (parathyroid hormone, vitamin D and metabolites, fibroblast growth factor 23), assessing the magnitude of phosphate reabsorption by the kidney is a crucial step. It makes it possible to distinguish between a primary disorder of renal phosphate reabsorption, associated with an intrinsic defect or endocrine disturbance, and a nutritional cause of phosphate deficiency. This strategy is described, and the potential consequences for therapeutic decisions are discussed.

Critical timing of ACEi initiation prevents compensatory glomerular hypertrophy in the remaining single kidney

Increasing evidence suggests that single in kidney states (e.g., kidney transplantation and living donation) progressive glomerulosclerosis limits kidney lifespan. Modeling shows that post-nephrectomy compensatory glomerular volume (GV) increase drives podocyte depletion and hypertrophic stress resulting in proteinuria and glomerulosclerosis, implying that GV increase could serve as a therapeutic target to prevent progression. In this report we examine how Angiotensin Converting Enzyme inhibition (ACEi), started before uninephrectomy can reduce compensatory GV increase in wild-type Fischer344 rats. An unbiased computer-assisted method was used for morphometric analysis. Urine Insulin-like growth factor-1 (IGF-1), the major diver of body and kidney growth, was used as a readout. In long-term (40-week) studies of uni-nephrectomized versus sham-nephrectomized rats a 2.2-fold increase in GV was associated with reduced podocyte density, increased proteinuria and glomerulosclerosis. Compensatory GV increase was largely prevented by ACEi started a week before but not after uni-nephrectomy with no measurable impact on long-term eGFR. Similarly, in short-term (14-day) studies, ACEi started a week before uni-nephrectomy reduced both GV increase and urine IGF-1 excretion. Thus, timing of ACEi in relation to uni-nephrectomy had significant impact on post-nephrectomy "compensatory" glomerular growth and outcomes that could potentially be used to improve kidney transplantation and live kidney donation outcomes.

End-Stage Renal Disease-Related Accelerated Immune Senescence: Is Rejuvenation of the Immune System a Therapeutic Goal?

End-stage renal disease (ESRD) patients exhibit clinical features of premature ageing, including frailty, cardiovascular disease, and muscle wasting. Accelerated ageing also concerns the immune system. Patients with ESRD have both immune senescence and chronic inflammation that are resumed in the so-called inflammaging syndrome. Immune senescence is particularly characterised by premature loss of thymic function that is associated with hyporesponsiveness to vaccines, susceptibility to infections, and death. ESRD-related chronic inflammation has multiple causes and participates to accelerated cardiovascular disease. Although, both characterisation of immune senescence and its consequences are relatively well-known, mechanisms are more uncertain. However, prevention of immune senescence/inflammation or/and rejuvenation of the immune system are major goal to ameliorate clinical outcomes of ESRD patients.

Renal effects of growth hormone in health and in kidney disease

Growth hormone (GH) and its mediator insulin-like growth factor-1 (IGF-1) have manifold effects on the kidneys. GH and IGF receptors are abundantly expressed in the kidney, including the glomerular and tubular cells. GH can act either directly on the kidneys or via circulating or paracrine-synthesized IGF-1. The GH/IGF-1 system regulates glomerular hemodynamics, renal gluconeogenesis, tubular sodium and water, phosphate, and calcium handling, as well as renal synthesis of 1,25 (OH)2 vitamin D3 and the antiaging hormone Klotho. The latter also acts as a coreceptor of the phosphaturic hormone fibroblast-growth factor 23 in the proximal tubule. Recombinant human GH (rhGH) is widely used in the treatment of short stature in children, including those with chronic kidney disease (CKD). Animal studies and observations in acromegalic patients demonstrate that GH-excess can have deleterious effects on kidney health, including glomerular hyperfiltration, renal hypertrophy, and glomerulosclerosis. In addition, elevated GH in patients with poorly controlled type 1 diabetes mellitus was thought to induce podocyte injury and thereby contribute to the development of diabetic nephropathy. This manuscript gives an overview of the physiological actions of GH/IGF-1 on the kidneys and the multiple alterations of the GH/IGF-1 system and its consequences in patients with acromegaly, CKD, nephrotic syndrome, and type 1 diabetes mellitus. Finally, the impact of short- and long-term treatment with rhGH/rhIGF-1 on kidney function in patients with kidney diseases will be discussed.

Renal function in short-statured children born small for gestational age and treated with growth hormone

BACKGROUND

Children born small for gestational age (SGA), particularly when associated with an extremely low birthweight (ELBW), have a higher risk of renal dysfunction. Growth hormone (GH) treatment is used to treat short-statured children born SGA; however, its effects on renal function remain elusive, especially in those born SGA with ELBW.

METHODS

Short-statured children born SGA (N = 42) were included. Subjects were subdivided into two groups based on their birthweight: the ELBW group (N = 15) with a birthweight of <1,000 g, and the non-ELBW group (N = 27) with birthweights ranging between 1,000 and 2,500 g. The creatinine-based estimated glomerular filtration rates (eGFR) before (pre-eGFR) and 5 years after GH treatment (post-eGFR) were compared. Correlations between eGFR, anthropometric, or birth parameters, and cumulative GH dose were evaluated using Spearman's rank correlation coefficient.

RESULTS

The ELBW group had a lower pre- and post-eGFR than the non-ELBW group. Five-year GH treatment did not significantly reduce eGFR in either group. Post-eGFR was positively associated with gestational week and birthweight. However, the cumulative GH dose was not correlated with pre-eGFR, post-eGFR, or percentage change in eGFR (%ΔeGFR). The change in bodyweight standard deviation score during GH treatment was positively correlated with %ΔeGFR in the ELBW group.

CONCLUSIONS

The current results indicated that GH treatment was unlikely a risk for the reduction in eGFR in short-statured children born SGA. However, eGFR should be carefully monitored, especially in those born SGA with ELBW because these subjects had lower eGFR than non-ELBW subjects.

Regulation of GH and GH Signaling by Nutrients

Growth hormone (GH) and insulin-like growth factor-1 (IGF-I) are pleiotropic hormones with important roles in lifespan. They promote growth, anabolic actions, and body maintenance, and in conditions of energy deprivation, favor catabolic feedback mechanisms switching from carbohydrate oxidation to lipolysis, with the aim to preserve protein storages and survival. IGF-I/insulin signaling was also the first one identified in the regulation of lifespan in relation to the nutrient-sensing. Indeed, nutrients are crucial modifiers of the GH/IGF-I axis, and these hormones also regulate the complex orchestration of utilization of nutrients in cell and tissues. The aim of this review is to summarize current knowledge on the reciprocal feedback among the GH/IGF-I axis, macro and micronutrients, and dietary regimens, including caloric restriction. Expanding the depth of information on this topic could open perspectives in nutrition management, prevention, and treatment of GH/IGF-I deficiency or excess during life.

Spine Bone Texture Assessed by Trabecular Bone Score in Active and Controlled Acromegaly: A Prospective Study

Context

Acromegalic patients have an increased vertebral fracture (VFx) risk due to bone quality reduction, independently of bone mineral density (BMD).

Objective

The aim of the study is to describe bone quality in acromegaly, measured by trabecular bone score (TBS), a noninvasive index for assessing bone microarchitecture.

Methods

We collected data from 18 patients (13 female, age 56.2 ± 15 years) newly diagnosed with acromegaly. Thirty-six age- and sex-matched healthy controls were also recruited. Pituitary function, bone and calcium-phosphorous metabolism, and BMD at spine and femur and TBS (by dual-energy x-ray absorptiometry) were assessed in acromegalic patients at diagnosis and 12 months after the achievement of insulin-like growth factor 1 (IGF-1) normalization.

Results

At diagnosis, BMD and the VFx prevalence were comparable between patients and controls (28.3 ± 5.9 vs 27.6 ± 3.7 and 11% vs 8.3%), whereas TBS was significantly lower in acromegalic patients (1.20 ± 0.13 vs 1.30 ± 0.06; P < .001) and carboxyterminal telopeptide (CTX) and osteocalcin were significantly higher compared to controls (707 ± 365.7 vs 371 ± 104.1 pg/mL; P = .001 and 31.6 ± 15.4 vs 17.0 ± 5.7 ng/mL; P = .001, respectively). One year after IGF-1 normalization, a significant reduction of bone turnover indexes was observed in the group of acromegalic patients surgically cured (osteocalcin decrease of 61.2%, CTX decrease of 60.3%) compared to the ones controlled by medical therapy (osteocalcin decrease of 39%, CTX decrease of 40.7%; P = .01 and P = .001, respectively). Despite these findings, no TBS or BMD variations were observed.

Conclusion

Acromegalic patients have impaired bone quality despite normal density. Achieving normal growth hormone secretion rapidly leads to the normalization of bone turnover.

Postoperative diabetes insipidus: how to define and grade this complication?

PURPOSE

Although transient diabetes insipidus (DI) is the most common complication of pituitary surgery, there is no consensus on its definition. Polyuria is the most overt symptoms of DI, but can also reflect several physiological adaptive mechanisms in the postoperative phase. These may be difficult to distinguish from and might coincide with DI. The difficulty to distinguish DI from other causes of postoperative polyuria might explain the high variation in incidence rates. This limits interpretation of outcomes, in particular complication rates between centers, and may lead to unnecessary treatment. Aim of this review is to determine a pathophysiologically sound and practical definition of DI for uniform outcome evaluations and treatment recommendations.

METHODS

This study incorporates actual data and the experience of our center and combines this with a review of literature on pathophysiological mechanisms and definitions used in clinical studies reporting of postoperative DI.

RESULTS

The occurrence of excessive thirst and/or hyperosmolality or hypernatremia are the best indicators to discriminate between pathophysiological symptoms and signs of DI and other causes. Urine osmolality distinguishes DI from osmotic diuresis.

CONCLUSIONS

To improve reliability and comparability we propose the following definition for postoperative DI: polyuria (urine production > 300 ml/hour for 3 h) accompanied by a urine specific gravity (USG) < 1.005, and at least one of the following symptoms: excessive thirst, serum osmolality > 300 mosmol/kg, or serum sodium > 145 mmol/L. To prevent unnecessary treatment with desmopressin, we present an algorithm for the diagnosis and treatment of postoperative DI.

Genetics of Acromegaly and Gigantism

Growth hormone (GH)-secreting pituitary tumours represent the most genetically determined pituitary tumour type. This is true both for germline and somatic mutations. Germline mutations occur in several known genes (AIP, PRKAR1A, GPR101, GNAS, MEN1, CDKN1B, SDHx, MAX) as well as familial cases with currently unknown genes, while somatic mutations in GNAS are present in up to 40% of tumours. If the disease starts before the fusion of the epiphysis, then accelerated growth and increased final height, or gigantism, can develop, where a genetic background can be identified in half of the cases. Hereditary GH-secreting pituitary adenoma (PA) can manifest as isolated tumours, familial isolated pituitary adenoma (FIPA) including cases with AIP mutations or GPR101 duplications (X-linked acrogigantism, XLAG) or can be a part of systemic diseases like multiple endocrine neoplasia type 1 or type 4, McCune-Albright syndrome, Carney complex or phaeochromocytoma/paraganglioma-pituitary adenoma association. Family history and a search for associated syndromic manifestations can help to draw attention to genetic causes; many of these are now tested as part of gene panels. Identifying genetic mutations allows appropriate screening of associated comorbidities as well as finding affected family members before the clinical manifestation of the disease. This review focuses on germline and somatic mutations predisposing to acromegaly and gigantism.

Late Health Effects of Partial Body Irradiation Injury in a Minipig Model Are Associated with Changes in Systemic and Cardiac IGF-1 Signaling

Clinical, epidemiological, and experimental evidence demonstrate non-cancer, cardiovascular, and endocrine effects of ionizing radiation exposure including growth hormone deficiency, obesity, metabolic syndrome, diabetes, and hyperinsulinemia. Insulin-like growth factor-1 (IGF-1) signaling perturbations are implicated in development of cardiovascular disease and metabolic syndrome. The minipig is an emerging model for studying radiation effects given its high analogy to human anatomy and physiology. Here we use a minipig model to study late health effects of radiation by exposing male Göttingen minipigs to 1.9–2.0 Gy X-rays (lower limb tibias spared). Animals were monitored for 120 days following irradiation and blood counts, body weight, heart rate, clinical chemistry parameters, and circulating biomarkers were assessed longitudinally. Collagen deposition, histolopathology, IGF-1 signaling, and mRNA sequencing were evaluated in tissues. Our findings indicate a single exposure induced histopathological changes, attenuated circulating IGF-1, and disrupted cardiac IGF-1 signaling. Electrolytes, lipid profiles, liver and kidney markers, and heart rate and rhythm were also affected. In the heart, collagen deposition was significantly increased and transforming growth factor beta-1 (TGF-beta-1) was induced following irradiation; collagen deposition and fibrosis were also observed in the kidney of irradiated animals. Our findings show Göttingen minipigs are a suitable large animal model to study long-term effects of radiation exposure and radiation-induced inhibition of IGF-1 signaling may play a role in development of late organ injuries.

Prolactin and Other Pituitary Disorders in Kidney Disease

Prolactin levels are increased in chronic kidney disease (CKD) as a result of reduced clearance and increased secretion. Hyperprolactinemia manifests as galactorrhea and hypogonadism. Treatment of hyperprolactinemia should focus on improving bothersome galactorrhea or hypogonadism by using dopamine agonists and/or replacement of sex hormone(s). Changes in the hypothalamic-pituitary-adrenal axis in CKD are characterized by increases in adrenocorticotropic hormone (ACTH) and cortisol levels, largely preserved circadian rhythms of ACTH and cortisol, and a normal response of cortisol to ACTH, metyrapone, and insulin-induced hypoglycemia. However, the hypothalamic-pituitary-adrenal axis is less inhibited by 1 mg dexamethasone but retains normal suppression by higher-dose dexamethasone. Diagnosis of adrenal insufficiency in CKD patients, as in normal subjects, usually is made by finding a subnormal cortisol response to ACTH. The mainstay of treatment of adrenal insufficiency is to replace glucocorticoid hormone. Cushing's disease in CKD is difficult to diagnose and relies on the dexamethasone suppression test and the midnight salivary cortisol test because the 24-hour urine free cortisol test is not useful because it is increased already in CKD. Treatment of Cushing's disease involves surgery, complemented by radiation and/or medical therapy if necessary. Growth hormone levels are increased and insulin-like growth factor 1 levels are normal in patients with CKD. In a normal patient with CKD, as in one with acromegaly, there can be a paradoxic increase in growth hormone after an oral glucose load. Therefore, diagnosis of acromegaly in renal insufficiency is challenging. The treatment of choice for acromegaly is surgery, although data for medical treatment for acromegaly in CKD are rare. In patients with renal impairment, arginine vasopressin levels are increased as a result of decreased clearance, and there also is impairment of arginine vasopressin signaling in renal tubules. Diabetes insipidus can be masked in advanced kidney disease until kidney transplantation. Diagnosis of the syndrome of inappropriate antidiuretic hormone is similar in mild or moderate kidney disease as in normal subjects, but is challenging in patients with advanced kidney disease owing to the impairment in urine dilution.

Increased SGK1 activity potentiates mineralocorticoid/NaCl-induced kidney injury

Serum and glucocorticoid-regulated kinase 1 (SGK1) stimulates aldosterone-dependent renal Na⁺ reabsorption and modulates blood pressure. In addition, genetic ablation or pharmacological inhibition of SGK1 limits the development of kidney inflammation and fibrosis in response to excess mineralocorticoid signaling. In this work, we tested the hypothesis that a systemic increase in SGK1 activity would potentiate mineralocorticoid/salt-induced hypertension and kidney injury. To that end, we used a transgenic mouse model with increased SGK1 activity. Mineralocorticoid/salt-induced hypertension and kidney damage was induced by unilateral nephrectomy and treatment with deoxycorticosterone acetate and NaCl in the drinking water for 6 wk. Our results show that although SGK1 activation did not induce significantly higher blood pressure, it produced a mild increase in glomerular filtration rate, increased albuminuria, and exacerbated glomerular hypertrophy and fibrosis. Transcriptomic analysis showed that extracellular matrix- and immune response-related terms were enriched in the downregulated and upregulated genes, respectively, in transgenic mice. In conclusion, we propose that systemically increased SGK1 activity is a risk factor for the development of mineralocorticoid-dependent kidney injury in the context of low renal mass and independently of blood pressure.NEW & NOTEWORTHY Increased activity of the protein kinase serum and glucocorticoid-regulated kinase 1 may be a risk factor for accelerated renal damage. Serum and glucocorticoid-regulated kinase 1 expression could be a marker for the rapid progression toward chronic kidney disease and a potential therapeutic target to slow down the process.