Increase of adhesion molecules, fibrinogen, type-1 plasminogen activator inhibitor and orosomucoid in growth hormone (GH) deficient adults and their modulation by recombinant human GH replacement

Effects of adult growth hormone deficiency and replacement therapy on the cardiometabolic risk profile

Adult growth hormone deficiency (AGHD) is considered a rare endocrine disorder involving patients with childhood-onset and adult-onset growth hormone deficiency (AoGHD) and characterized by adverse cardiometabolic risk profile. Besides traditional cardiovascular risk factors, endothelial dysfunction, low-grade inflammation, impaired adipokine profile, oxidative stress and hypovitaminosis D may also contribute to the development of premature atherosclerosis and higher cardiovascular risk in patients with AGHD. Growth hormone replacement has been proved to exert beneficial effects on several cardiovascular risk factors, but it is also apparent that hormone substitution in itself does not eliminate all cardiometabolic abnormalities associated with the disease. Novel biomarkers and diagnostic techniques discussed in this review may help to evaluate individual cardiovascular risk and identify patients with adverse cardiometabolic risk profile. In the absence of disease-specific guidelines detailing how to assess the cardiovascular status of these patients, we generally recommend close follow-up of the cardiovascular status as well as low threshold for a more detailed evaluation.

Adult growth hormone deficiency: clinical advances and approaches to improve adherence

Introduction: There have been significant clinical advances in the understanding of the diagnosis and benefits of long-term recombinant human growth hormone (rhGH) replacement in adults with GH deficiency (GHD) since its approval in 1996 by the United States Food and Drug Administration.Areas covered: We searched PubMed, Medline, CINAHL, EMBASE and PsychInfo databases between January 2000 and June 2019 for published studies evaluating adults with GHD. We reviewed the data of the oral macimorelin test compared to the GHRH plus arginine and the insulin tolerance tests that led to its approval by the United States FDA and European Medicines Agency for adult diagnostic testing. We summarize the clinical advances of long-term benefits of rhGH therapy and the potential effects of GH receptor polymorphisms on individual treatment responsiveness. We identify that non-adherence and discontinuation rates are high and recommend strategies to support patients to improve adherence. We also provide an overview of several long-acting GH (LAGH) preparations currently under development and their potential role in improving treatment adherence.Expert opinion: This article summarizes recent clinical advances in rhGH replacement therapy, the biological and molecular aspects that may influence rhGH action, and offers practical strategies to enhance adherence in adults with GHD.

The effect of growth hormone replacement in patients with hypopituitarism on pituitary tumor recurrence, secondary cancer, and stroke

Growth hormone replacement therapy has benefits for patients with hypopituitarism. The safety profile in regard to tumor recurrence or progression, development of secondary malignancies, or cerebrovascular stroke is still an area of debate. A comprehensive search of multiple databases-MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus was conducted through August 2015. Eligible studies that evaluated long-term adverse events in adult patients with hypopituitarism treated with growth hormone replacement therapy and reported development of pituitary tumor recurrence or progression, secondary malignancies, or cerebrovascular stroke were selected following a predefined protocol. Reviewers, independently and in duplicate, extracted data and assessed the risk of bias. Random-effects meta-analysis was used to pool relative risks and 95 % confidence intervals. We included 15 studies (published 1995-2015) that reported on 46,148 patients. Compared to non-replacement, growth hormone replacement therapy in adults with hypopituitarism was not associated with statistically significant change in pituitary tumor progression or recurrence (relative risk, 0.77; 95 % confidence interval, 0.53-1.13) or development of secondary malignancy (relative risk, 0.99; 95 % confidence interval, 0.70-1.39). In two retrospective studies, there was higher risk of stroke in patients who did not receive replacement (relative risk, 2.07; 95 % confidence interval, 1.51-2.83). The quality of evidence is low due to study limitations and imprecision. This systematic review and meta-analysis supports the overall safety of growth hormone therapeutic use in adults with hypopituitarism with no clear evidence of increased risk of pituitary tumor recurrence, malignancy, or stroke.

Mortality in adults with hypopituitarism: a systematic review and meta-analysis

PURPOSE

Hypopituitarism is a rare disorder with significant morbidity. To study the evidence on the association of premature mortality and hypopituitarism.

METHODS

A comprehensive search of multiple databases: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus was conducted through August, 2015. Eligible studies that evaluated patients with hypopituitarism and reported mortality estimates were selected following a predefined protocol. Reviewers, independently and in duplicate, extracted data and assessed the risk of bias.

RESULTS

We included 12 studies (published 1996-2015) that reported on 23,515 patients. Compared to the general population, hypopituitarism was associated with an overall excess mortality (weighted SMR of 1.55; 95 % CI 1.14-2.11), I ²  = 97.8 %, P = 0.000. Risk factors for increased mortality included younger age at diagnosis, female gender, diagnosis of craniopharyngioma, radiation therapy, transcranial surgery, diabetes insipidus and hypogonadism.

CONCLUSION

Hypopituitarism may be associated with premature mortality in adults. Risk is particularly higher in women and those diagnosed at a younger age.

Comparative effects of acute hypoglycemia and hyperglycemia on pro-atherothrombotic biomarkers and endothelial function in non-diabetic humans

BACKGROUND

The comparative effects of acute moderate hyperglycemia and hypoglycemia on in vivo endothelial function together with pro-inflammatory and pro-atherothrombotic responses in healthy individuals have not been determined.

METHODS

To investigate this question, 45 healthy subjects were compared during glucose clamp studies consisting of euinsulinemic hyperglycemia and hyperinsulinemic hyperglycemia (plasma glucose 11.1mmol/L, both with pancreatic clamps) and hyperinsulinemic euglycemia and hyperinsulinemic hypoglycemia (plasma glucose 5.1 and 2.9mmol/L, respectively). Two-dimensional Doppler ultrasound was used to determine brachial artery endothelial function.

RESULTS

Insulin levels during euinsulinemia hyperglycemia were 194±23 and (850±49-988±114) pmol/L during all hyperinsulinemic protocols. Responses of VCAM-1, ICAM-1, E-selectin, P-selectin, PAI-1, and IL-6 were increased (p<0.05-0.0001) during euinsulinemic hyperglycemia or hypoglycemia as compared to hyperinsulinemic euglycemia or hyperinsulinemic hyperglycemia. PAI-1 was increased (p<0.04) during hypoglycemia as compared to euinsulinemic hyperglycemia, and TNF-α responses were also increased during hypoglycemia as compared to hyperinsulinemic euglycemia or hyperinsulinemic hyperglycemia (p<0.05). In vivo endothelial function was similarly blunted by acute moderate hyperglycemia or hypoglycemia.

CONCLUSION

In summary, acute moderate hypoglycemia and euinsulinemic hyperglycemia can result in similar endothelial dysfunction and pro-atherothrombotic responses. Fibrinolytic balance was reduced by a greater extent by hypoglycemia as compared to moderate hyperglycemia. Acutely, hyperinsulinemia can prevent the acute pro-atherothrombotic and pro-inflammatory effects of moderate hyperglycemia but not hypoglycemia.

The effects of pituitary and thyroid disorders on haemostasis: potential clinical implications

Disturbances of coagulation and fibrinolysis are usually multifactorial and growing evidence suggests that endocrinopathies modulate the haemostatic balance. The thrombotic alterations in endocrine disorders range from mild laboratory clotting abnormalities with little clinical significance to serious thrombotic and bleeding disorders directly related to hormonal disturbances. This literature review focuses on presenting the current data on the effects of thyroid and pituitary disorders on various parameters of the haemostatic system. With the exception of overt hypothyroidism which appears to cause a bleeding tendency, the rest of the endocrinopathies discussed in this review (subclinical hypothyroidism, hyperthyroidism, endogenous hypercortisolaemia, growth hormone deficiency, acromegaly, prolactinoma/hyperprolactinaemia and hypogonadotrophic hypogonadism) are associated with a hypercoagulable and hypofibrinolytic state, increasing the overall cardiovascular risk and thromboembolic potential in these patients. In most studies, the haemostatic abnormalities seen in endocrine disorders are usually reversible with successful treatment of the underlying condition and biochemical disease remission. High-quality studies on larger patient cohorts are needed to produce robust evidence on the effects of endocrine disorders and their therapeutic interventions on coagulation and fibrinolysis, as well as on the long-term mortality and morbidity outcomes in association with endocrine-related haemostatic imbalance. Given the rarity of some of the endocrine disorders, multicentre studies are required to achieve this target.

Acute effects of hyperinsulinemia and hyperglycemia on vascular inflammatory biomarkers and endothelial function in overweight and obese humans

We investigated the separate and combined effects of hyperglycemia and hyperinsulinemia on markers of endothelial function, proinflammatory and proatherothrombotic responses in overweight/obese nondiabetic humans. Twenty-two individuals (13 F/9 M, BMI 30.1 ± 4.1 kg/m(2)) were studied during four randomized, single-blind protocols. The pancreatic clamp technique was combined with 4-h glucose clamps consisting of either 1) euinsulinemia-euglycemia, 2) euinsulinemia-hyperglycemia, 3) hyperinsulinemia-hyperglycemia, or 4) hyperinsulinemia-euglycemia. Insulin levels were higher (998 ± 66 vs. 194 ± 22 pmol/l) during hyperinsulinemia compared with euinsulinemia. Glucose levels were 11.1 mmol/l during hyperinsulinemia compared with 5.1 ± 0.1 mmol/l during euglycemia. VCAM, ICAM, P-selectin, E-selectin, IL-6, adiponectin, and PAI-1 responses were all increased (P < 0.01-0.0001), and endothelial function was decreased (P < 0.0005) during euinsulinemia-hyperglycemia compared with other protocols. Hyperinsulinemia in the presence of hyperglycemia prevented the increase in proinflammatory and proatherothrombotic markers while also normalizing vascular endothelial function. We conclude that 4 h of moderate hyperglycemia can result in increases of proinflammatory markers (ICAM, VCAM, IL-6, E-selectin), platelet activation (P-selectin), reduced fibrinolytic balance (increased PAI-1), and disordered endothelial function in a group of obese and overweight individuals. Hyperinsulinemia prevents the actions of moderate hyperglycemia to reduce endothelial function and increase proinflammatory and proatherothrombotic markers.

Impact of adult growth hormone deficiency on metabolic profile and cardiovascular risk [Review]

Adult growth hormone deficiency (GHD) is a well defined clinical condition, which is characterized by abnormal body composition, impaired physical activity and decreased quality of life. In addition, in recent years, growing interest has been shown towards cardiovascular risks in adult patients affected by GHD. In this regard, GHD is widely known to be associated with increased mortality, likely due to the increase of risk factors, such as central obesity, impaired lipid and glucose profiles and other less-known risk factors, such as inflammatory cytokines, endothelial dysfunction and oxidative stress. However, very few papers have recently discussed this topic. In this review, the aim is to clarify this issue by discussing evidence regarding the effects of adult GHD on metabolic and cardiovascular profiles.

Unusual effects of GH deficiency in adults: a review about the effects of GH on skin, sleep, and coagulation

Based on the literature data in the last two decades, growth hormone deficiency (GHD) in adults has been accepted as a clinical entity. Due to the presence of GH and IGF-I receptors throughout the body, the physiological effects of the GH-IGF-I axis are still under investigation. The effects of GH on skin, sleep, and coagulation parameters in adults have only been investigated in detail only in the recent years. In this review, our aim was to summarize the literature regarding the effects of GHD and GH replacement treatment on the skin, sleep, and coagulation parameters in adults.

Relation of insulin-like growth factor-I and IGF binding protein 3 with markers of inflammation: results of a population-based study

OBJECTIVE

Previous studies in acromegaly and growth hormone deficiency observed inverse associations between insulin-like growth factor-I (IGF-I) levels and inflammatory biomarkers including high-sensitive C-reactive protein (hsCRP), interleukin-6 or fibrinogen. We aimed to assess the relations between IGF-I or IGF binding protein 3 (IGFBP-3) levels and hsCRP, interleukin-6, fibrinogen and white blood cell count (WBC) in a population-based sample.

DESIGN AND PATIENTS

Data from 3480 subjects from the population-based Study of Health in Pomerania (SHIP) were used. IGF-I, IGFBP-3 and inflammatory biomarkers were measured. Analysis of variance (anova), quantile regression models and logistic regression models, adjusted for age, smoking, diabetes mellitus and waist circumference, were performed.

MEASUREMENTS AND RESULTS

anova and/or quantile regression showed inverse associations between IGF-I and hsCRP as well as positive associations between IGF-I and fibrinogen among both sexes. Furthermore, the odds of elevated fibrinogen levels increased with increasing IGF-I levels (per SD IGF-I increase: men: odds ratio (OR) 1·35 [95% confidence interval (CI) 1·04, 1·55]; women: OR 1·44 [95% CI 1·21, 1·71]) in both sexes, whereas the odds of increased hsCRP (women: OR 0·46 [95% CI 0·36, 0·58]) and interleukin-6 (men: odds ratio (OR) 0·77 [95% CI 0·61, 0·96]; women: OR 0·69 [95% CI 0·55, 0·86]) decreased.

CONCLUSION

Serum IGF-I levels are associated with inflammatory biomarkers including hsCRP, interleukin-6 and fibrinogen. Further experimental studies are needed to elucidate the mechanisms underlying the relation between the GH/IGF axis and the inflammatory system.

Growth hormone replacement normalizes impaired fibrinolysis: new insights into endothelial dysfunction in patients with hypopituitarism and growth hormone deficiency

BACKGROUND

Cardiovascular morbidity in adult patients with growth hormone deficiency (GHD) and hypopituitarism is increased. Clustering of cardiovascular risk factors leading to endothelial dysfunction and impaired fibrinolysis has also been reported and may account for progression to overt vascular changes in these patients. However, effect of long lasting GH replacement therapy on fibrinolytic capacity in GH deficient patients has not been investigated so far.

OBJECTIVE

To investigate fibrinolysis before and after challenge with venous occlusion in GHD patients with hypopituitarism before and during one year of growth hormone replacement.

DESIGN

Hospital based, interventional, prospective study.

INVESTIGATED SUBJECTS

Twenty one patient with GHD and fourteen healthy control subjects matched for age, sex and body mass index (BMI).

METHODS

Anthropometric, metabolic and fibrinolytic parameters were measured at the start and after three, six and twelve months of treatment with human recombinant GH.

RESULTS

At baseline GHD patients had significantly impaired fibrinolysis compared to healthy persons. During treatment with GH, significant changes were observed in insulin like growth factor 1(IGF-1) [from baseline 6.9(2.4-13.5) to 22.0(9.0-33.0) nmol/l after one month of treatment; p<0.01] and fibrinolysis. Improvement in fibrinolysis was mostly attributed to improvement of stimulated endothelial tissue plasminogen activator (t-PA) release in response to venous occlusion [from baseline 1.1(0.4-2.6) to 1.9(0.5-8.8) after one year of treatment; p<0.01].

CONCLUSION

Growth hormone replacement therapy has favorable effects on t-PA release from endothelium and net fibrinolytic capacity in GHD adults, which may contribute to decrease their risk of vascular complications.

Evaluation of coagulation and fibrinolytic parameters in adult onset GH deficiency and the effects of GH replacement therapy: a placebo controlled study

OBJECTIVE

Increased cardiovascular mortality/morbidity observed in patients with hypopituitarism is ascribed to growth hormone deficiency (GHD) because of its unfavorable cardiovascular risk profile. Abnormalities in the coagulation system may also contribute to increased cardiovascular morbidity/mortality. To get a better insight into the role of hemostasis in GHD we assessed several hemostatic markers at baseline and after 6 months of GH replacement therapy (GHRT). DESIGN-PATIENTS: Nineteen patients with adult onset GHD were enrolled (twelve patients into the treatment and seven patients into the placebo group) into the study. Platelet count, collagen/epinephrine closure time, collagen/ADP closure time, fibrinogen, prothrombin time (PT), activated partial thromboplastin time (aPTT), antithrombin III (AT III), protein C activity, protein S activity, lupus anticoagulant, antiphospholipid antibody immunoglobulin M, and antiphospholipid antibody immunoglobulin G were measured at baseline and 6 months after treatment.

RESULTS

The investigated parameters in the groups were similar at baseline except for low protein S (PS) activity. Protein S deficiency was observed in three of the patients in the GH treatment group at baseline, however the PS activity values normalized following GHRT. AT III and protein C activities decreased when compared to baseline values in the treatment group but not in the placebo group.

CONCLUSIONS

We observed protein S deficiency more frequent than seen in the general population and normalization of protein S activity and decreases, in other natural anticoagulants following GHRT. Further studies are required to understand the impact of these changes in cardiovascular morbidity and mortality in this patient population.

Mortality in patients with pituitary disease

Pituitary disease is associated with increased mortality predominantly due to vascular disease. Control of cortisol secretion and GH hypersecretion (and cardiovascular risk factor reduction) is key in the reduction of mortality in patients with Cushing's disease and acromegaly, retrospectively. For patients with acromegaly, the role of IGF-I is less clear-cut. Confounding pituitary hormone deficiencies such as gonadotropins and particularly ACTH deficiency (with higher doses of hydrocortisone replacement) may have a detrimental effect on outcome in patients with pituitary disease. Pituitary radiotherapy is a further factor that has been associated with increased mortality (particularly cerebrovascular). Although standardized mortality ratios in pituitary disease are falling due to improved treatment, mortality for many conditions are still elevated above that of the general population, and therefore further measures are needed. Craniopharyngioma patients have a particularly increased risk of mortality as a result of the tumor itself and treatment to control tumor growth; this is a key area for future research in order to optimize the outcome for these patients.

Growth hormone treatment on atherosclerosis: results of a 5-year open, prospective, controlled study in male patients with severe growth hormone deficiency

BACKGROUND

Severe GH deficiency (GHD) is associated with, increased cardiovascular risk and intima-media thickness (IMT) at major arteries.

OBJECTIVE

The objective of the study was to investigate the 5-yr effects of GH replacement on common carotid IMT and insulin resistance syndrome (IRS) (at least two of the following: triglycerides levels > or = 1.7 mmol/liter, high-density lipoprotein-cholesterol levels < or = 1.0 mmol/liter, blood pressure above 130/85 mm Hg, fasting glucose 6.1-7 or 2 hr after glucose 7.7-11.1 mmol/liter).

DESIGN

This was an interventional, open, prospective, controlled study.

PATIENTS

Patients included 35 men with severe GHD and 35 age-matched healthy men as controls.

INTERVENTION

All patients received standard replacement therapy; GH replacement was added in 22 patients (group A) and refused by 13 others (group B).

MEASUREMENTS

Five-year changes in IMT and IRS prevalence were measured.

RESULTS

At baseline, IMT was higher in the patients with (P < 0.001) and without IRS (P = 0.004) than in controls. Eighteen patients (51.4%) and two controls (5.7%; P < 0.0001) had IRS. At study end, use of lipid-lowering drugs (92.3, vs. 13.6 and 34.3%, P < 0.0001), glucose-lowering drugs (69.2 vs. 31.4 and 22.7%; P = 0.016), and antihypertensive drugs (61.5 vs. 20.0 and 4.5%; P < 0.0001) was higher in group B patients than controls and group A patients. IGF-I levels normalized in all group A patients and remained lower than -1 sd score in 77% of group B patients. IMT significantly decreased only in group A and significantly increased in controls and nonsignificantly in group B patients. IRS prevalence significantly reduced only in group A patients.

CONCLUSIONS

Severely hypopituitary GHD men have more frequently increased IMT at common carotid arteries and IRS than controls. After 5 years, only in GH replaced patients, IMT and prevalence of IRS decreased.

Growth hormone decreases visceral fat and improves cardiovascular risk markers in women with hypopituitarism: a randomized, placebo-controlled study

CONTEXT

Data regarding gender-specific efficacy of GH on critical endpoints are lacking. There are no randomized, placebo-controlled studies of physiological GH therapy solely in women.

OBJECTIVE

Our objective was to determine the effects of physiological GH replacement on cardiovascular risk markers and body composition in women with GH deficiency (GHD).

DESIGN

This was a 6-month, randomized, placebo-controlled, double-blind study.

SETTING

The study was conducted at the General Clinical Research Center.

STUDY PARTICIPANTS

43 women with GHD due to hypopituitarism were included in the study.

INTERVENTION

Study participants were randomized to receive GH (goal mid-normal serum IGF-1) or placebo.

MAIN OUTCOME MEASURES

Cardiovascular risk markers, including high-sensitivity C-reactive protein, tissue plasminogen activator, and body composition, including visceral adipose tissue by cross-sectional computed tomography, were measured.

RESULTS

Mean daily GH dose was 0.67 mg. The mean IGF-1 sd score increased from -2.5 +/- 0.3 to -1.4 +/- 0.9 (GH) (P < 0.0001 vs. placebo). High-sensitivity C-reactive protein decreased by 38.2 +/- 9.6% (GH) vs.18.2 +/- 6.0% (placebo) (P = 0.03). Tissue plasminogen activator and total cholesterol decreased, and high-density lipoprotein increased. Homeostasis model assessment-insulin resistance and other markers were unchanged. Body fat decreased [-5.1 +/- 2.0 (GH) vs. 1.9 +/- 1.0% (placebo); P = 0.002] as did visceral adipose tissue [-9.0 +/- 5.9 (GH) vs. 4.3 +/- 2.7% (placebo); P = 0.03]. Change in IGF-1 level was inversely associated with percent change in visceral adipose tissue (r = -0.61; P = 0.002), total body fat (r = -0.69; P < 0.0001), and high-sensitivity C-reactive protein (r = -0.51; P = 0.003).

CONCLUSIONS

Low-dose GH replacement in women with GHD decreased total and visceral adipose tissue and improved cardiovascular markers, with a relatively modest increase in IGF-1 levels and without worsening insulin resistance.

Markedly impaired fibrinolytic balance contributes to cardiovascular risk in adults with growth hormone deficiency

CONTEXT

Adults with GH deficiency (GHD) have multiple cardiovascular risk factors, including an unfavorable lipid profile and body composition as well as impairments in endothelial function and cardiac performance. We hypothesized that GHD is associated with elevated levels of plasminogen activator inhibitor-1 (PAI-1), the major inhibitor of plasminogen activation in the circulation.

OBJECTIVE

The objective of the study was to determine the fibrinolytic profile of adults with GHD in comparison with controls.

STUDY DESIGN AND PARTICIPANTS

This was a prospective, observational study including 12 adults with GHD. Twelve gender-, age-, and body mass index-matched adults served as controls.

MAIN OUTCOME MEASURES

The primary outcome measures were circadian plasma PAI-1 antigen with corresponding tissue-plasminogen activator (tPA) activity values. Endothelial function was assessed by flow-mediated vasodilation and fibrinolytic potential by venous occlusion test.

RESULTS

Adults with GHD exhibited an unfavorable 24-h fibrinolytic profile characterized by a mean 62% elevation in PAI-1 antigen (2.77 ng/ml after adjustment for baseline PAI-1; P = 0.049) in the setting of a mean 24% reduction in tPA activity (-0.17 IU/ml after adjustment for baseline tPA; P = 0.003). Fibrinolytic response was defective in GHD, as demonstrated by a sustained elevation in PAI-1 activity greater than 4 IU/ml after venous occlusion [7.2 IU/ml (interquartile range 0.8-17.4); P = 0.018]. Endothelial function was impaired in GHD, as quantified by percent flow-mediated vasodilation over 120 sec [area under the curve 3.8 (interquartile range -2.4 to 7.9) vs. 12.8 (interquartile range 2.1-19.4); P = 0.043].

CONCLUSIONS

Adults with GHD demonstrate alterations in plasma fibrinolytic balance, including elevated levels of PAI-1 antigen with decreased tPA activity. These changes may contribute to the increased cardiovascular morbidity within this population.

Obese adults with primary growth hormone resistance (Laron Syndrome) have normal endothelial function

OBJECTIVE

Classic Laron Syndrome (LS) is a recessive disease of insulin-like growth factor I (IGF-I) deficiency and primary growth hormone insensitivity, clinically characterized by dwarfism and marked obesity. The aim of the current study was to investigate the impact of long-term IGF-I deficiency on flow-mediated dilation (FMD) in 11 non-IGF-I-treated LS adults with long-term IGF-I deficiency who on stress echocardiography were found to have reduced cardiac dimensions and output, but normal left ventricular (LV) ejection fraction at rest and LV contractile reserve following stress.

DESIGN

Following an overnight fast we assessed percent improvement in endothelium-dependent FMD (%FMD) and endothelium-independent nitroglycerin (%NTG)-mediated vasodilation non-invasively in the brachial artery, using high resolution ultrasound in 11 non-treated adult patients with LS without known coronary artery disease, and compared them to 11 age- and sex-matched healthy controls. All subjects underwent symptom-limited exercise testing (Bruce protocol).

RESULTS

LS patients had a significantly higher body mass index (29+/-6 vs. 25+/-2 kg/m(2), p=0.04), lower low-density lipoprotein cholesterol (142+/-28 vs. 176+/-12 mg/dl, p=0.03) and a smaller mean brachial artery diameter (4.63+/-0.72 vs. 5.70+/-1.06 mm, p=0.01) compared to controls. However, brachial artery %FMD and %NTG were not significantly different between the LS patients and controls (13.1+/-6.2% vs. 15.4+/-5.2%, p=0.28 and 22.3+/-6.0% vs. 18.9+/-6.2%, p=0.30; respectively). Cardiac performance, assessed by exercise duration time and metabolic equivalents (METs), was significantly greater in control subjects than in LS patients (10.3+/-2.0 vs. 6.0+/-1.4 min, p<0.01 and 10.2+/-2.0 vs. 7.2+/-1.4 METs, p<0.01; respectively).

CONCLUSIONS

FMD was found to be within normal limits in non-IGF-I-treated adult patients with LS, despite congenital absence of IGF-I and obesity.

Peripheral fibrinolytic markers, soluble adhesion molecules, inflammatory cytokines and endothelial function in hypopituitary adults with growth hormone deficiency

BACKGROUND

Increased mortality due to cardiovascular disease has been described in adult patients with untreated GH deficiency (GHD). GH replacement has been demonstrate to improve vascular reactivity and reverse early atherosclerotic changes in adults with GHD.

OBJECTIVE

Assessment of fibrinolytic markers, soluble adhesion molecules, inflammatory cytokines and endothelial function in hypopituitary adults with GHD at baseline and 1 year after GH replacement therapy.

METHODS

We studied 10 patients with GHD (five men and five women; aged 45.6 +/- 10.4 years) at baseline and 1 year after GH replacement therapy compared with a control group (nine men and 16 women) matched for age and body mass index (BMI). All subjects, patients and controls, were life-long nonsmokers, normotensive and nondiabetic. The following variables were recorded: anthropometric and body composition variables, serum concentrations of glucose, insulin and C-peptide; thrombin anti-thrombin (TAT) fragments and fibrin degradation product D-dimer, which were determined by an enzyme-linked immunosorbent assay (ELISA); IGF-I by radioimmunoassay (RIA); C-reactive protein (CRP) by highly sensitive immunonephelometry; E-selectin, P-selectin, soluble intercellular cell adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) by ELISA. The assessment of endothelial function in vivo was measured with a Doppler device.

RESULTS

Patients with GHD without GH substitution had higher hip/waist ratio and body fat than controls. Insulin, C-peptide and triglyceride concentrations were also higher. Our results demonstrated no difference in fibrinogen and in TAT fragment concentrations among patients and controls. E-selectin concentrations were higher in patients than in controls (26.1 +/- 11 vs. 10.7 +/- 6.2 microg/l, P = 0.0001). P-selectin, sICAM-1, sVCAM-1, IL-6, MCP-1 and CRP were similar in the two groups. Vascular reactivity and carotid intima-media thickness (IMT) were also similar in patients and controls. After 1 year of GH treatment we found no changes in biochemical parameters, fibrinolytic markers, soluble adhesion molecules, inflammatory cytokines and endothelial function.

CONCLUSION

Adults with GHD show some subtle changes in soluble adhesion molecules but our data suggest no beneficial effects of GH over these markers in relationship to endothelial function. Factors other than GH treatment, such as differences in age, degree of obesity, the presence of diabetes mellitus and arterial hypertension or tobacco consumption, could explain the observed increase in markers of vascular risk in GH-deficient patients.

Effects of growth hormone on insulin resistance and atherosclerotic risk factors in obese type 2 diabetic patients with poor glycaemic control

OBJECTIVE

We aimed to evaluate the combined effects of GH treatment and diet restriction on lipolysis and anabolism, insulin resistance and atherosclerotic risk factors in obese patients with type 2 diabetes mellitus (T2DM).

SUBJECTS

This randomized, double-blind, placebo-controlled study included 24 obese T2DM patients (male : female = 12 : 12, mean age 53.7 +/- 7.2 years) with poor glycaemic control (fasting plasma glucose 10.673 +/- 1.121 mmol/l, HbA(1C) 9.9 +/- 2.3%). Sixteen of these patients were treated with recombinant human GH (1-1.5 units/day, 5 days/week) while undergoing diet restriction and exercise for 12 weeks.

METHODS

Anthropometric and bioelectrical impedance measurements were undertaken to determine the lean body mass and total body fat. Computed tomography (CT) was performed to estimate visceral and subcutaneous fat distribution at the umbilicus level and the muscle area of the midthigh. Insulin resistance was measured by the insulin tolerance test (ITT) and by the homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

The ratios VSR (visceral fat area/subcutaneous fat area) and VMR (visceral fat area/thigh muscle area) were significantly decreased in the GH-treated group compared to the control group. An increase in lean body mass was observed in the GH-treated group. Levels of total cholesterol, triglyceride, free fatty acid (FFA), fibrinogen, and plasminogen activator inhibitor-1 (PAI-1) were significantly decreased after GH treatment. Fasting glucose levels decreased similarly (P < 0.05 anova) in both groups during the treatment period. Fasting C-peptide levels significantly increased, whereas insulin levels significantly decreased, in the GH-treated group, but no changes were observed in the control group. The insulin sensitivity index (ISI) was significantly increased in the GH-treated group (1.3 +/- 1.4 vs. 1.9 +/- 1.0%/min, P < 0.05).

CONCLUSIONS

GH treatment in obese T2DM patients with poor glycaemic control is beneficial in decreasing the amount of visceral fats, and may therefore result in improvements in insulin resistance, atherosclerotic risk factors and dyslipidaemia.

Massive cardiac thrombosis in a patient with Sheehan's syndrome

Growth hormone deficiency (GHD) is a risk factor for increased cardiovascular disease, and it has been recently demonstrated that abnormalities in coagulation system might contribute to the increased cardiovascular morbidity and mortality. However, there is not enough data related to the major thrombotic events in GH-deficient patients. We describe the case of a 62-year-old woman with Sheehan's syndrome who developed massive cardiac thrombosis. She was hospitalized with acute pulmonary edema. ECG revealed high ventricular responsive atrial fibrillation (AF) and T-wave inversion on precordial leads. The ejection fraction of left ventricle (LVEF) was measured as 60% by transthoracic echocardiography (TTE) and there was 2nd degree mitral regurgitation with concentric hypertrophic LV walls. Transesophagial echocardiography (TEE) established thrombi both at right atrium and left atrial appendix. Before anticoagulant therapy several hemostatic and fibrinolytic markers were measured. Except increased D-dimer concentration (763.14 mug/L (0-325)) we did not observe any pathological finding in these parameters. After 14 days of discharge, the patient was admitted to the intensive care unit with upper gastrointestinal bleeding. The warfarin and salicylate were stopped for two months. At the end of two months, the patient was again hospitalized with congestive heart failure and there was a high ventricular responsive AF on ECG. TEE was performed and three thrombi were demonstrated at right atrium (RA), left atrium (LA) and left ventricle (LV). There was no active bleeding on upper GIS endoscopy and anticoagulant therapy was restarted. In this particular case massive cardiac thrombi involving three chambers (LA, RA, LV) were more extensive than expected in AF. Moreover, there was a 2nd degree mitral regurgitation in the patient, and based on previous studies mitral regurgitation has been associated with less prevalent LA spontaneous echo contrast and fewer thromboembolic events. Therefore we hypothesized that severe GHD in the present case might be the major contributing factor in massive cardiac thrombosis. In summary, based on previous data there is increased risk of thromboembolic events in GHD although the mechanism is unclear yet. Our case is the first case showing massive cardiac thrombosis in a severe GH-deficient patient with Sheehan's syndrome. Therefore, patients with GHD should be screened carefully for thrombus in clinical practice, and further studies need to be done to understand the relation between GHD and coagulation system.

Cardiovascular disease and risk factors: the role of growth hormone

Clinical studies in patients with acromegaly have shown that growth hormone (GH) exerts both short- and long-term effects on the structure and function of the heart. Moreover, chronic growth hormone deficiency (GHD) has been associated with impaired cardiac performance, low heart rate and impaired left ventricular systolic function. Exercise capacity in patients with GHD is significantly reduced and in some severely affected individuals, dilated cardiomyopathy and heart failure has been reported. GHD has also been associated with a number of risk factors for cardiovascular disease. Altered lipoprotein metabolism and elevated fibrinogen and plasminogen activator inhibitor-1 activity are associated with GHD, and the risk of hypertension is increased in GH-deficient men. Subcutaneous and intra-abdominal fat mass have also been found to be abnormally high in these patients. These effects may contribute to an increased risk of death from cardiovascular disease. GH is therefore an important factor in the development and function of the cardiovascular system. In this paper, the effects of GH on the physiological mechanisms of the cardiovascular system are discussed, including the effect of GHD on cardiovascular disease risk. We will also discuss the effects of long-term GH replacement therapy in this patient population.

Growth hormone replacement reduces C-reactive protein and large-artery stiffness but does not alter endothelial function in patients with adult growth hormone deficiency

Hypopituitary patients have an increased risk of vascular mortality that may relate to growth hormone deficiency (GHD). We investigated the effects of 6 months of GH therapy on large- and small-artery function and high-sensitivity C-reactive protein (hsCRP) in a cohort of GH-deficient patients. Sixteen hypopituitary patients were randomized to 6 months of GH therapy or no treatment, then vice versa. hsCRP, 24-h blood pressure (BP) and pulse wave velocity (PWV) were measured and resistance arteries were used to construct concentration-response curves to endothelium-dependent and -independent agents. GH therapy increased IGF-1 from 60 +/- 7.2 to 167 +/- 16.2 microg/l [confidence interval (CI) 94.9, 138.8, P < 0.001]. hsCRP declined after 6 months of GH from 3.8 +/- 0.88 to 2.0 +/- 0.49 mg/l (CI 0.73, 3.57, P = 0.006). Mean arterial BP fell from 91.7 +/- 1.5 to 89.3 +/- 1.2 mmHg (CI 0.81, 4.07, P = 0.005), as did PWV (8.1 +/- 0.4 to 6.7 +/- 0.5 m/s). The decline in PWV correlated with the decline in hsCRP (r = 0.68, P = 0.01). Resistance artery function was unchanged after GH therapy. GH replacement may lead to differentially altered production of vasorelaxant agents from the endothelium of large and small arteries. Reduction in vascular inflammation may be associated with reduced vascular risk.

Recombinant GH replacement in hypopituitary adults improves endothelial cell function and reduces calculated absolute and relative coronary risk

OBJECTIVE

Adult GH deficiency (GHD) is linked to endothelial dysfunction and vascular disease. We examined the effect of 12 months of GH therapy on endothelial function, C-reactive protein (CRP) and coronary risk.

DESIGN

Open-design intervention study.

PATIENTS

Fourteen GH-deficient patients (nonsmokers, without diabetes, hypertension or vascular disease) studied before, 6 months and 12 months after GH therapy.

MEASUREMENTS

Flow-mediated dilatation (FMD), carotid intima-media thickness (IMT) thrombomodulin (TM), E-selectin, CRP, lipid profile, blood pressure and anthropometric data were recorded. We used the Framingham equation to calculate coronary risk.

RESULTS

FMD improved (7.5 +/- 1.62 vs. 11.93 +/- 1.52, P = 0.038). Overall there was no change in IMT, TM, E-selectin or CRP. The correlation between TM and FMD showed a trend for statistical significance (r = -0.54, P = 0.056). Changes in CRP correlated with change in IGF-1 (r = -0.67, P = 0.012); E-selectin correlated with high density lipoprotein (HDL)-cholesterol (r = -0.60, P = 0.028), triglycerides (r = 0.68, P = 0.01) and waist-to-hip ratio (WHR) (r = 0.71, P = 0.006). Systolic (127.36 +/- 4.47 vs. 120.36 +/- 3.50, P = 0.017) and diastolic (84.71 +/- 2.73 vs. 76.93 +/- 2.03, P = 0.005) blood pressure decreased. HDL-cholesterol increased (0.70 +/- 0.05 vs. 0.93 +/- 0.06, P = 0.001). WHR decreased (0.90 +/- 0.02 to 0.88 +/- 0.02, P = 0.043) without changes in weight or body mass index (BMI). Ten-year absolute (P = 0.009) and relative (P = 0.002) cardiac risk decreased.

CONCLUSION

Biophysical test of endothelial function (FMD) improved after 12 months of GH therapy but there was no significant change in biochemical endothelial or inflammatory markers. Calculated coronary risk decreased mainly due to reduction in systolic and diastolic blood pressure and increase in HDL-cholesterol.

Insulin-like growth factor-1 deficiency determines increased intima-media thickness at common carotid arteries in adult patients with growth hormone deficiency

OBJECTIVE

To investigate the role of IGF-1 on intima-media thickness (IMT) at common carotid arteries by Doppler ultrasonography.

SUBJECTS

Thirty-nine patients (17 women, 22 men, aged 25-70 years) with severe GH deficiency (GHD), 19 with normal and 20 with low IGF-1 levels, and 39 sex-, age- and body mass index (BMI)-matched healthy controls.

RESULTS

Patients with GHD showed abnormalities in lipid profile, and increased fibrinogen levels, mean IMT (0.88 +/- 0.26 vs. 0.69 +/- 0.14 mm, P < 0.001), and systolic and diastolic peak velocity (P < 0.001) compared to controls. Eight patients (18%) and one control (2.1%, P = 0.04) had well-defined plaques. In controls, but not in patients with GHD, mean carotid IMT was correlated with age (r = 0.78, P < 0.001). In both controls (r = -0.82; P < 0.0001) and patients with GHD (r = -0.84, P < 0.0001), serum IGF-1 levels were inversely correlated with mean IMT at common carotid arteries. At the stepwise multiple regression, the variables most significantly related to IMT in GH-deficient patients were total cholesterol levels (t = 5.2, P < 0.001), followed by disease duration (t = 2.4, P = 0.02), while in controls the variables most significantly related to IMT were IGF-1 levels (t = -9.9, P < 0.001), followed by low density lipoprotein (LDL)-cholesterol levels (t = -2.3, P = 0.02). Compared to patients with normal IGF-1 levels, those with low IGF-1 levels had lower high density lipoprotein (HDL)-cholesterol levels (1.0 +/- 0.2 vs. 1.3 +/- 0.2 mmol/l, P = 0.0002), and higher glucose (54.3 +/- 6.1 vs. 48.9 +/- 5.9 mmol/l, P = 0.008), insulin (25.2 +/- 6.8 vs. 18.8 +/- 6.0 mUl/l, P = 0.004), total cholesterol (7.1 +/- 1.1 vs. 4.9 +/- 0.6 mmol/l, P < 0.0001), total/HDL-cholesterol ratio (7.2 +/- 1.8 vs. 3.9 +/- 0.7, P < 0.0001), fibrinogen levels (319.8 +/- 56.9 vs. 241.8 +/- 53.0 mg/dl, P < 0.0001) and mean IMT at common carotid arteries (1.05 +/- 0.25 vs. 0.69 +/- 0.07 mm, P < 0.0001). Atherosclerotic plaques were found only in GH-deficient patients with low IGF-1 levels.

CONCLUSIONS

GH-deficient patients have alterations in lipid profile with an increase in the total/HDL-cholesterol ratio, which is an index of increased cardiovascular risk, but only patients with IGF-1 deficiency have increased IMT.

Long-Term Challenges in Growth Hormone Treatment

Growth hormone deficiency (GHD) is defined biochemically as a response to hypoglycaemia with a peak GH concentration of less than 5 microg/l. The 'GHD syndrome' is a range of psychological and physical symptoms that are associated with GHD, which include increased central adiposity, decreased bone mineral density, abnormal lipid profiles, decreased cardiovascular performance, reduced lean body mass (LBM), social isolation, depressed mood and increased anxiety. Importantly, the combination of physical and psychological problems can often result in a reduced quality of life. A number of trials have shown that GH replacement therapy can lead to a substantial improvement in GHD associated symptoms. Following up to 12 months of treatment with GH, LBM increased, left ventricular systolic function improved and the mean volume of adipose tissue fell. After only 4 months of treatment, a rise in exercise capacity was recorded, and after 2 years' treatment, isokinetic and isometric muscle strength had normalized in proximal muscle groups. Feelings of well-being and vitality also improved significantly. However, studies on the effects of treatment on insulin sensitivity in GH-deficient patients have had conflicting results. In this paper, we will discuss the long-term consequences of GHD and the effects of GH replacement therapy.

Polymorphism in the promoter region of the insulin-like growth factor I gene is related to carotid intima-media thickness and aortic pulse wave velocity in subjects with hypertension

BACKGROUND AND PURPOSE

Low circulating levels of insulin-like growth factor I (IGF-I) have been associated with an increased risk for atherosclerosis. Absence of the 192-bp (wild-type) allele in the promoter region of the IGF-I gene has been associated with low circulating IGF-I levels. We examined the role of this polymorphism in relation to blood pressure and 2 early markers of atherosclerosis: carotid intima-media thickness (IMT) and aortic pulse wave velocity (PWV).

METHODS

A total of 5132 subjects of the Rotterdam Study, aged 55 to 75 years, were included in this study. In 3769 subjects who did not use blood pressure-lowering medication, the association between the IGF-I polymorphism and blood pressure was examined. In the total population, and in 3484 normotensive subjects, 1648 hypertensive and 462 untreated hypertensive subjects, the association between this polymorphism and IMT and PWV was examined.

RESULTS

Mean systolic and diastolic blood pressure did not differ between genotypes. In hypertensive subjects IMT was significantly increased in noncarriers of the 192-bp allele (0.83 mm) compared with heterozygous or homozygous carriers (0.80 mm) (P=0.04). PWV was also significantly higher in hypertensive subjects who were noncarriers of the 192-bp allele (14.3 m/s) compared with heterozygous (14.1 m/s) or homozygous carriers (13.7 m/s) (P=0.02). Findings were more pronounced in hypertensive subjects without medication use. In normotensive subjects, no association between this polymorphism, IMT, and PWV was observed.

CONCLUSIONS

Our study suggests that hypertensive subjects who have low IGF-I levels because of a genetic polymorphism in the IGF-I gene are at increased risk of developing atherosclerosis.

Growth hormone deficiency and vascular risk

The importance of growth hormone deficiency (GHD) in adult life has become more apparent over the last decade. As well as a distinct clinical syndrome there is a significant excess risk of cardiovascular disease. Although it is difficult to ascertain what part is played by the original pituitary disorder and the concomitant replacement hormonal therapies, there is clear evidence that GHD is associated with known cardiovascular risk factors such as body shape, lipid profile, insulin resistance, blood pressure, vessel wall morphology and haemostatic factors. Novel means of assessing vascular risk such as pulse wave velocity and flow-mediated dilatation can also estimate the risk without invasive procedures. The role of possible mediators of endothelial function such as nitric oxide and free radicals is being investigated further. Replacement of GH in GH-deficient patients leads to many effects on the above indices, some but not all of which are associated with reduced vascular risk. Long-term follow-up studies of morbidity and mortality are required for an accurate assessment of the beneficial effects of therapy.

Effects of GH on lipid peroxidation and neutrophil superoxide anion-generating capacity in hypopituitary adults with GH deficiency

OBJECTIVES

Untreated growth hormone deficiency (GHD) is implicated in the increased cardiovascular risk associated with adult hypopituitarism. Oxidative stress, predisposing to lipid peroxidation, may be an important mediator of endothelial dysfunction, a pro-atherogenic state associated with adult GHD.

DESIGN AND PATIENTS

In a randomized, double-blind, placebo-controlled study we investigated the effects of GH replacement on low-density lipoprotein (LDL) oxidation and neutrophil superoxide (O(-)(2)) generating capacity in 32 GHD adults (19 males, 13 females; age range 19-64 years) over 3 months. Thirty age- and sex-matched healthy controls were also studied.

MEASUREMENTS

Lipid hydroperoxides (HPOs) in plasma were measured using the ferrous oxidation with xylenol orange (FOX) assay. The susceptibility of LDL to oxidation was assessed by the copper-catalysed lag phase of LDL oxidation. Neutrophil O(-)(2)- generating capacity was assessed by a lucigenin-based chemiluminescent assay of NADPH oxidase activity. Body composition was assessed using bioelectrical impedance analysis.

RESULTS

Compared to controls, GHD subjects had higher LDL cholesterol (4.0 +/- 0.8 vs. 3.5 +/- 0.9 mmol/l, P < 0.01) and higher triglyceride concentrations (2.3 +/- 1.5 vs. 1.1 +/- 0.7 mmol/l, P < 0.001) but lower HDL cholesterol (1.1 +/- 0.3 mmol/l vs. 1.4 +/- 0.4 mmol/l, P < 0.01), lower levels of HPOs (0.72 +/- 0.35 vs. 0.92 +/- 0.20 microm, P < 0.01) and lower basal (2.5 +/- 1.5 vs. 4.5 +/- 2.3 mV/5 x 10(5) neutrophils, P < 0.01) and peak post-activation levels (23.2 +/- 11.1 vs. 34.4 +/- 15.6 mV/5 x 10(5) neutrophils, P < 0.01) of neutrophil O(-)(2)- generation. GH replacement resulted in an increase in HPOs from 0.70 +/- 0.39 to 0.86 +/- 0.19 microm (P < 0.05), although there was no change in the lag time of LDL oxidation. Neutrophil O(-)(2)- generating capacity was enhanced with a rise in basal O(-)(2)- generation from 2.8 +/- 1.4 to 5.4 +/- 4.6 mV/5 x 10(5) neutrophils (P < 0.05) and in peak post-activation O(-)(2)- generation from 21.9 +/- 9.5 to 35.8 +/- 21.7 mV/5 x 10(5) neutrophils (P < 0.05). LDL cholesterol was reduced from 4.1 +/- 0.8 mmol/l to 3.5 +/- 0.8 mmol/l (P < 0.01). No significant changes in measured parameters occurred in the placebo group.

CONCLUSIONS

Adult GHD is associated with reduced lipid peroxidation and impaired neutrophil O(-)(2)- generating capacity, both of which are reversible with GH replacement. Our data suggest that: (i) that oxidative stress is not a major feature of the pro-atherogenic state in hypopituitary adults with GHD and (ii) a role for GH in modulating neutrophil function and leucocyte-lipoprotein interactions.

Hypopituitarism and atherosclerosis

In the last decade, retrospective cohort data has provided evidence of premature atherosclerosis in patients with hypopituitarism which may account for the recently observed increased death rate from vascular events in these patients. The exact mechanism(s) for such propensity to atherosclerotic vascular disease is not yet completely clear. It is possible that hormonal factors may be the initiating mechanisms with subsequent secondary metabolic abnormalities acting as risk factors for development of atherosclerosis. This seems to be more evident in female hypopituitary patients compared with their male counterparts. Female patients have higher frequency and more pronounced abnormalities of various risk factors as well as surrogate markers of early vascular disease. This may explain why morbidity and mortality in women is in excess of men in retrospective epidemiological studies. Addressing abnormal hormonal factors, especially in females, is a primary objective in managing these patients both in the clinical arena as well as in trials designed to reduce the risk of atherosclerotic vascular disease in these patients. While short-term growth hormone treatment may ameliorate some of the vascular risk factors and improve endothelial function, it remains to be shown whether this translates into long-term reduction in morbidity and mortality from vascular, especially cerebrovascular, disease.