Normal Insulin-like Growth Factor 1 Levels Research Articles

Endocrinologic Outcome Following Endonasal Transphenoidal Excision of Growth Hormone Secreting Pituitary Adenomas

Background: Endonasal Transphenoidal Approach for excision of pituitary adenomas has been gaining popularity over the traditional microsurgical approach. The objective of this study is to assess the rate of hormonal recovery following endonasal transphenoidal excision of growth hormone secreting pituitary macroadenoma in out center. Methods: In this prospective observational study all cases subjected to endonasal transphenoidal excision of growth hormone secreting pituitary adenoma, during the study period from January 2019 to December 2020 at National Neurosurgical Referral Center, Bir Hospital, Kathmandu were included in this study. Preoperative and postoperative patient characteristics were recorded. Hormonal remission was defined as normal insulin-like growth factor-1 level at 3 months follow-up. Results: A total of 24 cases were included. The mean age of acromegaly cases was 39.42±10.41 years (24-56 years), with male to female ratio of 0.71:1. Majority (9) of cases had a Knosp grade 1.Thirteen cases had a Wilson-Hardy Extension Grade 0. Majority (11) of cases had a Wilson-Hardy Invasion Grade I. Three cases developed post-operative CSF leak, which recovered after lumbar drainage with no sequel. Five cases developed epistaxis which resolved with nasal packing. Sixty three percent (15 cases) had normal IGF-1 levels at 3 months follow up. Conclusion: Endoscopic endonasal transphenoidal approach to excision of growth hormone secreting pituitary adenomas is a safe and effective modality at achieving hormonal control in our setting.

Association of Body Mass Index with Insulin-like Growth Factor-1 Levels among 3227 Chinese Children Aged 2–18 Years

Insulin-like growth factor-1 (IGF-1) levels are affected by nutritional status, yet there is limited research exploring the association between body mass index (BMI) and IGF-1 levels among children. This cross-sectional study included 3227 children aged 2-18 years without specific diseases, whose height, weight, and pubertal stages were measured and assessed by pediatricians. BMI standard deviation scores (BMISDS) were used to categorize children as underweight (BMISDS < -2); normal-weight (-2 ≤ BMISDS ≤ 1); overweight (1 < BMISDS ≤ 2); and obese (BMISDS > 2). Children were divided into low-level (<-0.67 SD) and nonlow-level (≥-0.67 SD) groups based on IGF-1 standard deviation scores (IGF-1SDS). The association between IGF-1 and BMI as categorical and continuous variables was explored by Binary logistic regression, the restrictive cubic spline model, and the generalized additive model. Models were adjusted by height and pubertal development. Recursive algorithm and multivariate piecewise linear regression were further utilized to assess the threshold of the smooth curve. IGF-1 levels varied by BMI categories, with the highest levels observed in the overweight group. The proportion of low IGF-1 levels in underweight, normal-weight, overweight, and obese groups was 32.1%, 14.2%, 8.4%, and 6.5%, respectively. The risk odds of low IGF-1 levels in underweight children were 2.86-, 2.20-, and 2.25-fold higher than in children with normal weight before adjustment, after adjustment for height, and after adjustment for height and puberty, respectively. When analyzing the association between BMI and low IGF-1 levels, dose-response analysis demonstrated an inverted J-shaped relationship between BMISDS and low IGF-1 levels. Lower or higher BMISDS increased the odds of low IGF-1 levels, and significance was retained in underweight children but not in obese children. When BMI and IGF-1 levels were used as continuous variables, the relationship between the BMISDS and IGF-1SDS followed a nonlinear inverted U shape. IGF-1SDS increased with the increase of BMISDS (β = 0.174, 95% CI: 0.141 to 0.208, p < 0.01) when BMISDS was less than 1.71 standard deviation (SD) and decreased with the increase of BMISDS (β = -0.358, 95% CI: -0.474 to -0.241, p < 0.01) when BMISDS was greater than 1.71 SD. The relationship between BMI and IGF-1 levels was found to depend on the type of variable, and extremely low or high BMI values could result in a tendency toward low IGF-1 levels, emphasizing the importance of maintaining a normal BMI range for normal IGF-1 levels.

Safety and Efficacy of Switching Injected Peptide Long-Acting Somatostatin Receptor Ligands to Once Daily Oral Paltusotine: ACROBAT Edge Phase 2 Study

Patients with acromegaly not cured by surgery are often initially treated with injected peptide long-acting somatostatin receptor ligands (SRLs). Non-peptide small molecules can also activate the somatostatin receptor and do so with a high degree of precision for the target therapeutic receptor subtype. Paltusotine (formerly CRN00808) is a small molecule somatostatin type 2 (SST2) receptor agonist with high oral bioavailability (70%) and pharmacokinetic profile suitable for once daily dosing. In healthy volunteers, paltusotine has been shown to lower growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels. We hypothesized that patients with acromegaly could switch from injected SRLs to once daily oral paltusotine while maintaining baseline IGF-1 levels. ACROBAT Edge (NCT03789656) was a single-arm study designed to evaluate the safety and efficacy of switching from injected SRLs to paltusotine in patients with acromegaly. The primary analysis population consisted of those who had not achieved normal IGF-1 levels despite stable therapy with long-acting octreotide or lanreotide. Eligible patients received their last injection of SRL 4 weeks prior to switching to once daily oral paltusotine monotherapy for a 13-week treatment period. The starting dose of 10 mg per day was uptitrated in 10 mg increments at specified study visits to a maximal dose of 40 mg per day based on protocol specified study drug toleration and IGF-1 criteria. The primary endpoint was change in IGF-1 from baseline to the completion of the 13-week treatment period. Statistical testing was based on non-parametric Wilcoxon Sign Rank test of whether the median change is different from zero. In addition, the rise in IGF-1 during a 4-week washout period was used to provide supportive evidence of efficacy. Twenty-five patients were enrolled in the primary analysis group, three patients discontinued from the study for non-study drug related reasons, two during the treatment period and one during the washout period after completing treatment. The primary endpoint was achieved as paltusotine treatment resulted in no significant change in IGF-1 levels at week 13 compared to baseline [change in IGF-1 =-0.034 (-0.107, 0.107), median (IQR), p>0.6]. Of the 23 patients who completed the dosing period, 20 (87%) achieved IGF-1 levels at the end of treatment that were within 20% of baseline or lower. Median IGF-1 values rose significantly after paltusotine washout (p<0.0001). The most common treatment-emergent adverse events (>10%) included: headache, arthralgia, fatigue, peripheral swelling, paresthesia and hyperhidrosis. There were no discontinuations due to adverse events and no treatment related serious adverse events. These results suggest that patients with acromegaly treated with injected SRLs can switch to oral paltusotine while maintaining IGF-1 and that paltusotine appeared to be well tolerated.

Early postoperative prediction of both disease remission and long-term disease control in acromegaly using the oral glucose tolerance test.

Transsphenoidal surgery (TSS) is the cornerstone of acromegaly treatment. Two biochemical parameters, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels, sometimes diverge postoperatively; however, it is important to maintain disease control without further treatment, regardless of whether these parameters converge. This study investigated whether remission and long-term disease control could be predicted using early postoperative GH and IGF-1 levels. We reviewed 36 consecutive surgically treated patients with acromegaly. IGF-1 levels and minimum GH levels during an oral glucose tolerance test (OGTT) were evaluated at 2 weeks, as well as at 3 months postoperatively. After comparison between the remission and nonremission groups, we analyzed whether early postoperative parameters could predict remission and long-term disease control. Twenty-five patients (69.4%, Group A) achieved remission within 1 year postoperatively. Of the remaining patients (median follow-up period, 53 months), seven (19.5%, Group B) maintained normal IGF-1 levels without treatment, whereas four (11.1%, Group C) required additional treatment. GH levels <1.5 ng/mL measured on the morning after surgery and nadir GH levels <0.7 ng/mL during the OGTT conducted at 2 weeks postoperatively were predictive of remission, with the latter demonstrating 95.2% sensitivity and 100% specificity. All group C patients had nadir GH levels ≥0.7 ng/mL during the OGTT and IGF-1 levels ≥SD +3 at 2 weeks postoperatively. Early postoperative nadir GH levels during the OGTT and IGF-1 levels at 2 weeks postoperatively demonstrated excellent predictive value for both endocrinological remission and the necessity for additional treatment.

The association between insulin-like growth factor 1 levels within reference range and early postoperative remission rate in patients with Cushing’s disease

ABSTRACT Introduction The relationship between growth hormone (GH)/insulin-like growth factor 1 (IGF-1) and glucocorticoids (GC) was examined in various studies. Long-term GC treatment was shown to decrease GH concentration and, interestingly, to increase IGF-1 concentration. We performed a retrospective study in order to examine how preoperative IGF-1 concentrations vary within the reference range and if tertiles of age- and sex-adjusted normal IGF-1 are predictive for early postoperative remission in the patients with Cushing’s Disease (CD). Patients and Methods Patients diagnosed with CD were retrospectively evaluated. After the exclusion of 67 patients, a final cohort of 250 CD patients were included. Age- and sex-adjusted normal IGF-1 levels were divided into tertiles (T1, T2 and T3). Early postoperative remission was defined as a nadir morning cortisol concentration measured within the first 3 consecutive days following surgery of less than 5 µg/dL (138 nmol/L). Results Early postoperative remission rate was the lowest in T1 and highest in T3; 49.1% (n = 28) versus 77.3% (n = 75), p = .001, respectively. Binary logistic regression analysis showed the remission rate in T3 was three times higher than that in T1 (p = .003). Cortisol and ACTH concentration were significantly higher and GH concentrations were significantly lower in T1 compared to those in the other two tertiles. Conclusions As the first study evaluating the correlation between early postoperative remission rate in patients with CD and the tertiles of normal age- and sex-adjusted IGF-1 levels, we have shown that higher IGF-1 levels could predict better outcome in CD.

Combined therapy of somatostatin analogues with pegvisomant for the treatment of acromegaly: a meta-analysis of prospective studies

BackgroundAcromegaly is a rare, chronic and severe disease. Drug therapy including somatostatin analogues (SAs), dopamine receptor agonists and growth hormone receptor antagonists (pegvisomant, PEG) are commonly used to treat patients who do not respond to surgery. The use of combination therapy with PEG and SAs has become more common over the last decade. We performed this study to accurately evaluate the effect of combination therapy of SAs with PEG on acromegalic patients.MethodsPubMed, EMBASE, The Cochrane Library, ClinicalTrials.gov, Scopus, Web of Science, Chinese Biomedical Literature Database and Trip database were searched for relevant studies. Prospective clinical trials treating acromegaly with the co-administration of SAs and PEG were included. We performed a meta-analysis by using Stata 12.1. Sensitivity analysis was conducted to explore heterogeneity.ResultsNine studies were included in this meta-analysis. The overall rate of serum insulin-like growth factor 1 (IGF-1) normalization was 66% (95% CI: 52–78%; I2 = 62.59%). The combination therapy did not significantly change patients’ fasting plasma glucose (ES: 0.011 mmol*L− 1; 95% CI: − 0.374 to 0.397 mmol*L− 1; P = 0.954) or glycosylated haemoglobin (ES: − 0.074%; 95% CI: − 0.166 to 0.315%; P = 0.544) while decreasing the fasting plasma insulin (ES: − 21.487 pmol*L-1; 95% CI: − 35.713 to − 7.260 pmol*L-1; P = 0.003). Elevation of liver enzyme levels was found in 14% (95% CI: 8 to 21%) of the patients. There was no significant difference for serious adverse events and treatment discontinuation due to adverse event between SAs monotherapy group and combination therapy group.ConclusionsCombined therapy of SAs and PEG effectively normalized IGF-1 levels in most of the patients whose IGF-1 level was greater than the upper limit of normal after high dose SAs monotherapy. The therapy also decreased significantly FPI levels with a neutral effect on glucose parameters in acromegaly patients. Moreover, elevated liver enzyme levels were observed in a small number of patients, which suggests a need for liver function monitoring.Trial registrationWe have our protocol registered in PROSPERO. (Registration number: CRD42019115549).

Long-term endocrinological outcomes of gamma knife radiosurgery in acromegaly patients

Gamma knife radiosurgery (GKS) is a treatment option for recurrent or persistent disease in patients with acromegaly. ObjectiveWe aimed to retrospectively evaluate acromegaly patients who had undergone GKS in terms of pituitary hormone status, efficacy of GKS, and prognostic factors. MethodOne-hundred and ten acromegaly patients who underwent GKS, and who were referred to our outpatient endocrinology clinic between 2007 and 2017, were included in the study. Anterior pituitary hormones and radiology imaging during follow-up were recorded. Remission for acromegaly was defined as a normal insulin-like growth factor 1 (IGF-1) level adjusted for age and gender, and a random growth hormone (GH) level < 1 ng/ml. Endocrine control was defined as normal GH and IGF-1 levels under medication. ResultsAfter a mean follow-up of 6.5 ± 4.7 years; remission, endocrine control, and uncontrolled status was observed in 16.4%, 60%, and 23.6% of patients; respectively. Adenoma volume was decreased after GKS (P < .0001). Remnant adenoma diameter was higher in the uncontrolled group compared to the remission and endocrine control group. The presence of tumor extension was associated with disease status (P = .03) and higher initial GH and IGF-1 levels. The mean time after GKS to remission was 26.5 months. Six (5.4%) patients had new-onset pituitary deficiency after GKS. In the multivariate analysis, pre-GKS IGF-1 levels and patient's age were associated with disease status. ConclusionGKS is an effective adjuvant treatment with minimal side effects to control GH and IGF-1 levels, increase remission rates, endocrine control, and reduce tumor diameter in persistent acromegaly patients after surgery.

Normal Insulin-like Growth Factor 1 During Somatostatin Receptor Ligand Treatment Predicts Surgical Cure in Acromegaly.

Treatment with somatostatin receptor ligands (SRLs) is often given before pituitary surgery to patients with acromegaly. To study whether the response to treatment with SRLs is predictive of surgical outcome. Retrospective, observational study. Tertiary care center. We investigated 272 patients with acromegaly who had been treated with an SRL between 1990 and 2018. All patients underwent pituitary surgery performed by a skilled neurosurgeon. Outcome of pituitary surgery in patients who had normalization of insulin-like growth factor 1 (IGF-1) levels during SRL therapy in comparison with patients who did not normalize IGF-1 levels. Normalization of IGF-1 levels during SRL treatment occurred in 62 patients (22.8%) and was similar for the 3 different types of SRL (P = .88). Surgical remission occurred in 59.6% of the patients. Patients who normalized IGF-1 levels during SRL treatment had a higher probability of surgical cure than patients without IGF-1 normalization (83.9% vs 52.4%, respectively; P < .001). Multivariate analysis confirmed that lack of cavernous sinus invasion, small maximum tumor diameter, and IGF-1 normalization during SRL therapy were the only factors independently associated with a favorable surgical outcome. Our study demonstrates that the normalization of IGF-1 levels during treatment with SRLs is an independent predictive factor of a favorable surgical outcome. The underlying mechanisms remain unclear, but an optimal response to medical therapy may be a characteristic of less aggressive tumors that are more likely to be entirely removed at surgery.

An Incidental Collision Tumor of the Sella Turcica

To present a case describing an incidentally discovered pituitary mass that was found to be a collision tumor containing 2 distinct histologic cell types: (1) a growth hormone (GH)-secreting pituitary adenoma, and (2) a gangliocytoma. Sellar gangliocytomas are very rare benign neuroblastic tumors that originate from the posterior pituitary. The majority are associated with pituitary adenomas. The co-existence of these 2 morphologically distinct tumors is known as a collision tumor, a rare disease entity of which the pathogenesis is not well understood. We present a case of a woman with an incidentally discovered pituitary mass that was found to be a collision tumor. A 44-year-old woman presented with an incidentally discovered pituitary mass and was found to have elevated insulin-like growth factor 1 (IGF-1) levels. The patient underwent endoscopic transsphenoidal excision of the pituitary mass. Histopathology of the tumor revealed a mixed pituitary adenoma that stained for GH and prolactin, and a gangliocytoma. Postoperatively, the patient developed temporary central adrenal insufficiency and permanent diabetes insipidus. Postoperative lab studies revealed a normal IGF-1 level, and a magnetic resonance imaging scan showed no residual or recurrent tumor. While sellar gangliocytoma is a rare lesion, when it is present, a co-existing pituitary adenoma should also be suspected. Further investigation should be done to determine the pathophysiology of these collision tumors, which could be beneficial in guiding diagnosis and treatment.

Effects of Growth Hormone Replacement on Peripheral Muscle and Exercise Capacity in Severe Growth Hormone Deficiency.

The aim of this study is to evaluate the effect of growth hormone therapy (rGH) on mitochondrial function on peripheral muscle and to correlate with exercise capacity in subjects with severe adult growth hormone deficiency (GHD). Six months, double-blind, randomized, crossover, placebo-controlled trial of subcutaneous rGH in 17 patients with GHD. Quadriceps muscle biopsies were obtained at baseline, 3 months, and 6 months to measure succinate dehydrogenase (SDH) to assess mitochondrial activity. Exercise capacity was measured with cardiopulmonary exercise testing. Lipids, glycemic parameters, and body fat levels were also measured. Serum insulin-like growth factor 1 (IGF1) levels reduced fat mass by 3.2% (p < 0.05) and normalized with rGH in the active phase (p < 0.005). Patients showed an increase in SDH (p < 0.01) from base line that differed between placebo and rGH therapy treatment groups (p < 0.05): those treated by rGH followed by placebo showed a significant increase in SDH (p < 0.001) followed by a decrease, with a significant between group difference at the end of 6 months (p < 0.05). No significant improvements or correlation with exercise capacity was found. Short-term rGH for 3 months normalized IGF1 levels, reduced fat mass, and had a significant effect on mitochondrial function, but exercise capacity was unchanged. Number ISRCTN94165486.

Growth Hormone Excess in Children with Optic Pathway Tumors Is a Transient Phenomenon

Background/Aims: Growth hormone (GH) excess in children with chiasmal optic pathway tumors (OPT), often associated with neurofibromatosis type 1 (NF1), is likely underrecognized. These children have elevated insulin-like growth factor 1 (IGF-1) levels, evidence of rapid growth despite treatment of precocious puberty, and failure to suppress GH levels following oral glucose challenge. The aim of this report is to describe the treatment course and natural history of this rare clinical condition in 7 patients. Methods: This is a descriptive case series of 5 children previously described and 2 additional children more recently diagnosed at our institution. All 7 children had clinical and biochemical evidence of GH excess and received treatment with the somatostatin analog octreotide. Results: Length of treatment varied among the patients. Five of the 7 patients have had resolution of GH excess and currently have normal IGF-1 levels without treatment. Conclusions: Unrestrained GH secretion occurs in a subset of children with OPT with potential adverse outcomes. Since GH excess appears to resolve over time, the benefit of treatment to alter outcomes or prevent tumor progression is unclear.

Effect of pasireotide on glucose- and growth hormone-related biomarkers in patients with inadequately controlled acromegaly.

The purpose of this study was to gain more insight into the mechanism of action of pasireotide in patients who completed the PAOLA study. PAOLA was a 24-week, Phase III, randomized, three-arm study of pasireotide LAR 40 and 60 mg versus octreotide LAR 30 mg or lanreotide Autogel 120 mg in patients with inadequately controlled acromegaly. The current work was a planned exploratory objective of the PAOLA study that evaluated changes in levels of growth hormone (GH), insulin-like growth factor 1 (IGF-1), IGF-binding proteins (IGFBP-2, IGFBP-3), glycated haemoglobin (HbA1c) and fasting plasma glucose (FPG) in each treatment arm. Responders to pasireotide LAR (mean GH levels <2.5 μg/L and normal IGF-1 levels at 24 weeks) had lower GH and IGF-1 levels at baseline (GH 5.1 ng/mL, IGF-1 519 ng/mL) than non-responders (GH 7.9 ng/mL, IGF-1 672 ng/mL). Frequency of hyperglycaemia after pasireotide treatment was similar in responders and non-responders and depended more on the baseline FPG level. 47 % of all patients treated with pasireotide LAR (40 or 60 mg) did not receive antidiabetic medication at any time during this study. This is the first study to evaluate the treatment effect of pasireotide on key hormonal and glycaemic biomarkers and to identify potential predictors of pasireotide-associated hyperglycaemia. Pre-treatment glucose status may be predictive of the development of pasireotide-associated hyperglycaemia. A large subset of patients with acromegaly does not experience major disturbances in glucose homeostasis while receiving pasireotide LAR.Electronic supplementary materialThe online version of this article (doi:10.1007/s12020-016-0895-8) contains supplementary material, which is available to authorized users.

Low insulin resistance after surgery predicts poor GH suppression one year after complete resection for acromegaly: a retrospective study.

Remission of acromegaly is defined as a nadir in GH <1.0 ng/mL during a 75-g oral glucose tolerance test (75gOGTT) and insulin-like growth factor-1 (IGF-1) normalization. Recently, a lower cut-off value for GH nadir (<0.4 ng/mL) has been proposed. We retrospectively evaluated the prevalence and clinical characteristics of postoperative cases with normalized IGF-1 levels and a GH nadir of 0.4-1.0 ng/mL one year after complete resection of GH-secreting pituitary adenoma (GHoma). We included 110 cases of acromegaly with complete adenoma resection, no preoperative treatment, preoperative glycosylated hemoglobin <6.5%, preoperative basal plasma glucose <126 mg/dL, GH nadir <1.0 ng/mL during a 75gOGTT, and normalized IGF-1 at the first postoperative year evaluation, whereupon patients were divided into two groups: control (GH nadir <0.4 ng/mL) and high GH (GH nadir >0.4 ng/mL). Clinical parameters, including measures of insulin secretion and resistance, were compared between groups. The high GH group included 10 patients (9.1%) and had a lesser level of insulin resistance immediately following surgery and at the first postoperative year evaluation. On single regression analysis, insulin resistance immediately following surgery was predictive of and correlated with the GH nadir at the first postoperative year evaluation. The GH nadir at the first postoperative year evaluation may be insufficient in patients with normalized IGF-1 with low insulin resistance immediately following complete resection of GHoma. Careful evaluation is needed to assess remission in such patients.

Acromegaly with Normal Insulin-Like Growth Factor-1 Levels and Congestive Heart Failure as the First Clinical Manifestation.

The leading cause of morbidity and mortality in patients with acromegaly is cardiovascular complications. Myocardial exposure to excessive growth hormone can cause ventricular hypertrophy, hypertension, arrhythmia, and diastolic dysfunction. However, congestive heart failure as a result of systolic dysfunction is observed only rarely in patients with acromegaly. Most cases of acromegaly exhibit high levels of serum insulin-like growth factor-1 (IGF-1). Acromegaly with normal IGF-1 levels is rare and difficult to diagnose. Here, we report a rare case of an acromegalic patient whose first clinical manifestation was severe congestive heart failure, despite normal IGF-1 levels. We diagnosed acromegaly using a glucose-loading growth hormone suppression test. Cardiac function and myocardial hypertrophy improved 6 months after transsphenoidal resection of a pituitary adenoma.

Long-term Changes in Serum IGF-1 Levels After Successful Surgical Treatment of Growth Hormone–Secreting Pituitary Adenoma

Successful treatment of acromegaly is known to normalize serum insulin-like growth factor 1 (IGF-1) levels within days after surgery. However, our clinical observations indicate that many cases of acromegaly show delayed normalization of serum IGF-1 levels after complete tumor resection. To study long-term changes of the serum IGF-1 levels in acromegalic patients for whom surgical treatment was thought to be successful. A retrospective observational study was performed with 46 acromegalic patients with no residual tumor on sellar magnetic resonance imaging, and a nadir growth hormone of less than 0.4 μg/L on a postoperative oral glucose tolerance test. In all patients, serum IGF-1 levels returned to the normal reference values for age and sex during the observational period (12-132 months). The mean duration from the time of surgery until IGF-1 normalization was 10 months (range, 3 days-57 months). Twenty-seven patients (59%) reached normal IGF-1 ranges within 3 months of surgery, whereas 19 patients (41%) experienced delayed (>3 months) IGF-1 normalization. Eleven patients (24%) recovered normal IGF-1 levels 12 to 57 months after surgery. The possibility of delayed IGF-1 cure was increased 8.8-fold with an immediate postoperative IGF-1 level increase of 100 μg/L. Satisfactory remission of acromegaly by IGF-1 criteria was delayed in a large proportion of acromegalic patients, especially those with high postoperative IGF-1 levels. Hence, additional treatment can be delayed in clinically stable acromegalic patients who show no evidence of residual tumors on postoperative magnetic resonance imaging and a normal growth hormone suppressive response to a glucose load.

Gamma knife radiosurgery for clinically persistent acromegaly

Gamma knife radiosurgery (GKRS) is an important additional strategy for unresected clinically active pituitary adenomas. Radiosurgery for acromegaly aims to achieve tumor growth control and endocrine remission, potentially obviating the need for lifetime medication suppression therapy. Forty patients with clinically active acromegaly underwent GKRS between 1988 and 2009. Thirty-four patients had undergone prior surgical resection. The median follow-up interval was 72 months (range 24-145). Endocrine remission was defined as growth hormones (GH) level <2.5 ng/ml and a normal insulin-like growth factor 1 (IGF-1) level (age and sex adjusted) off growth hormone inhibiting drugs for at least 3 months. Endocrine control was defined as normal GH and IGF-1 levels on suppression medication. Endocrine remission was achieved in 19 (47.5 %) patients and endocrine control in four additional (10.0 %) patients. Patients with lower IGF-1 level and with tumors that were less invasive of the cavernous sinus before GKRS were associated with better GH remission rates. Imaging-defined local tumor control was achieved in 39 (97.5 %) patients (27 had tumor regression). One patient with delayed tumor progression underwent a second GKRS procedure. Three other patients had repeat GKRS because of persistently elevated and clinically symptomatic GH and IGF-1 levels. Sixteen (40.0 %) patients eventually developed a new pituitary axis deficiency at a median onset of 36 months after radiosurgery. No patient developed new visual dysfunction. Gamma knife radiosurgery, which is most often applied in clinically symptomatic acromegaly persistent after initial microsurgery, was most effective when the tumor was less invasive of the cavernous sinus and when patients had lower IGF-1 levels before GKRS. Almost one half of the patients no longer required long term medication suppression.

Six-month preoperative octreotide treatment in unselected, de novo patients with acromegaly: effect on biochemistry, tumour volume, and postoperative cure

Treatment with somatostatin analogues is the primary medical treatment of acromegaly. Controversies still exist whether acute octreotide effect predicts long-term biochemical effects, tumour regression or surgical cure. This prospective study investigates effect of 6-month treatment with octreotide long-acting repeatable (LAR) on insulin-like growth factor-1 (IGF-1) and growth hormone (GH) levels, pituitary function, tumour regression and postoperative cure in de novo acromegalic patients. After a baseline evaluation including fasting hormone levels, MRI scan and an acute 50 μg octreotide test, 32 patients were treated with octreotide LAR 20 mg every 28th day for 6 months before surgery. Treatment effects on IGF-1 and GH levels, serum hormone levels and tumour volume were monitored. Surgical cure was evaluated 3 months postoperatively. Mean tumour volume reduction was 35%, in one-third of the patients more than 50%, while approximately one-third achieved biochemical remission evaluated by normalized IGF-1 levels. The GH reduction following an acute octreotide test was 81 ± 19% and associated with long-term GH reduction (r = 0·78, P < 0·0005). However, neither acute (r = 0·29, P = 0·12) nor the long-term octreotide effect (r = 0·11, P = 0·58) on GH levels was associated with tumour volume reduction and did not predict subsequent surgical cure. Six months of long-acting octreotide using a fixed dose, 1/3 of the patients came in biochemical remission, while 2/3 had significant tumour reduction. Moreover, an acute effect of octreotide seemed to be a prerequisite for long-term effect.

Growth hormone mediates pubertal skeletal development independent of hepatic IGF-1 production

Deficiencies in either growth hormone (GH) or insulin-like growth factor 1 (IGF-1) are associated with reductions in bone size during growth in humans and animal models. Liver-specific IGF-1-deficient (LID) mice, which have 75% reductions in serum IGF-1, were created previously to separate the effects of endocrine (serum) IGF-1 from autocrine/paracrine IGF-1. However, LID mice also have two- to threefold increases in GH, and this may contribute to the observed pubertal skeletal phenotype. To clarify the role of GH in skeletal development under conditions of significantly reduced serum IGF-1 levels (but normal tissue IGF-1 levels), we studied the skeletal response of male LID and control mice to GH inhibition by pegvisomant from 4 to 8 weeks of age. Treatment of LID mice with pegvisomant resulted in significant reductions in body weight, femur length (Le), and femur total area (Tt.Ar), as well as further reductions in serum IGF-1 levels by 8 weeks of age, compared with the mean values of vehicle-treated LID mice. Reductions in both Tt.Ar and Le were proportional after treatment with pegvisomant. On the other hand, the relative amount of cortical tissue formed (RCA) in LID mice treated with pegvisomant was significantly less than that in both vehicle-treated LID and control mice, indicating that antagonizing GH action, either directly (through GH receptor signaling inhibition) or indirectly (through further reductions in serum/tissue IGF-1 levels), results in disproportionate reductions in the amount of cortical bone formed. This resulted in bones with significantly reduced mechanical properties (femoral whole-bone stiffness and work to failure were markedly decreased), suggesting that compensatory increases of GH in states of IGF-1 deficiency (LID mice) act to protect against a severe inhibition of bone modeling during growth, which otherwise would result in bones that are too weak for normal and/or extreme loading conditions. © 2011 American Society for Bone and Mineral Research.

Effectiveness of self- or partner-administration of an extended-release aqueous-gel formulation of lanreotide in lanreotide-naïve patients with acromegaly

Surgical resection is often not curative in patients with acromegaly and long-acting somatostatin analogues (lanreotide or octreotide) are often needed. This study assessed the efficacy and safety of self- or partner-administration of lanreotide in patients with acromegaly. This was a six-month, single-arm, open-label study conducted at 13 endocrinology clinics. Fifty-nine patients received deep subcutaneous lanreotide injections every 28 days. Twelve patients started on 120 mg lanreotide and forty-seven started on 90 mg lanreotide. At week 16, the dose was adjusted to 60, 90 or 120 mg based on insulin-like growth factor-1 (IGF-1) levels at week 12. Fifty-nine patients with acromegaly either switched from long-acting octreotide (switch; n = 33) or were somatostatin analogue treatment-naïve or not currently taking long-acting octreotide (“other”; n = 26). The key endpoints included the percentage of patients/partners able to self- or partner-inject lanreotide and those with normal IGF-1 or growth hormone (GH) levels at week 24/early termination. 100% of patients/partners correctly self- (n = 41) or partner-injected (n = 18) lanreotide by week 4. By week 24/early termination, IGF-1 levels were controlled in 93.7% of switch and 46.2% of “other” patients, while GH levels were controlled in 76.9% and 39.1% of patients, respectively. Both IGF-1 and GH were controlled in 73.1% of switch and 30.4% of “other” patients. Most switch patients (81%) reported they preferred lanreotide over long-acting octreotide for future use (P = 0.0001). Self- or partner-administration of lanreotide is generally well tolerated and associated with IGF-1 and GH control in many lanreotide-naïve patients with acromegaly.

Extracerebellar MRI—Lesions in Ataxia Telangiectasia Go Along with Deficiency of the GH/IGF-1 Axis, Markedly Reduced Body Weight, High Ataxia Scores and Advanced Age

Ataxia telangiectasia (AT) is a rare autosomal recessive disorder characterized by progressive ataxia, neurodegeneration, immunodeficiency, and cancer predisposition. Pathoanatomical studies reported a degeneration of cerebellar Purkinje cells as the striking feature of the disease. Although recent studies suggested the involvement of extracerebellar structures such as the brainstem and basal ganglia, this has rarely been studied in human AT. Thus, we performed a detailed cliniconeuroradiological investigation of 11 AT patients, aged 8 to 26 years by collecting clinical neurological data, ataxia scores, growth status, body mass index (BMI), growth hormone (GH), and insulin-like-growth factor 1 (IGF-1) and correlated them to extracerebellar neuroimaging findings in human AT. Neuroimaging was done by cranial and spine magnetic resonance imaging (MRI) with T1- and T2-weighted spin-echo and fluid attenuated inversion recovery sequences. We compared clinical and neuroradiological findings of six patients with IGF-1 levels and BMI below the third percentile to five patients with normal IGF-1 serum levels and BMI above the third percentile. Three of the six first mentioned patients older than 20 years and two patients older than 12 years showed noticeable high Klockgether ataxia scores above 25 points. Three of these patients presented with marked hyperintense lesions in the cerebral white matter of T2-weighted MR images. Interestingly, all six patients suffered from marked spinal atrophy. Two of the patients presented with severe extra-pyramidal symptoms, but only one patient showed associated MRI abnormalities of the basal ganglia. MRI in patients with normal IGF-1 levels showed the expected cerebellar lesions in four patients, whereas spinal atrophy was found only in two patients. There was no affection of the cerebral white matter or basal ganglia in this group. We conclude that central cerebral white matter affection, spinal atrophy, and extrapyramidal symptoms are more often present in patients with pronounced deficiency of the GH/IGF-1 axis accompanied by markedly reduced body weight and high ataxia scores. This may point to a major role of IGF-1 and nutritional status in neuroprotective signaling.