Does the age of onset of growth hormone deficiency affect cardiac performance? A radionuclide angiography study

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.

MRI Assessment of Cardiac Function and Morphology in Adult Patients With Growth Hormone Deficiency: A Systematic Review and Meta-Analysis

BACKGROUND

Adult GH deficiency (GHD) has been described as a heterogeneous condition characterized by many clinical modifications, such as metabolic alterations, impaired quality of life, and increased mortality. The clinical relevance of cardiac involvement remains, however, only partially elucidated.

METHODS

PubMed/Medline, EMBASE, Cochrane library, OVID and CINAHL databases were systematically searched until February 2022 for studies evaluating cardiac function and morphology by magnetic resonance imaging in adult patients with GHD. Effect sizes were pooled through a random-effect model.

RESULTS

Four studies were considered in the meta-analysis. With respect to the left ventricle, GHD patients were characterized by a lower stroke-volume-index (-3.6 ml/m², standardized mean difference (SMD) -0.60, 95%CI [-1.15,-0.05], p=0.03), lower end-diastolic-volume-index (-6.2 ml/m², SMD -0.54, 95%CI [-0.97,-0.10], p=0.02) and, after accounting for possible biases, lower mass-index (-15.0 g/m², SMD -1.03, 95%CI [-1.89,-0.16], p=0.02). With respect to the right ventricle, a lower end-diastolic-volume-index (-16.6 ml/m², SMD -1.04, 95%CI [-2.04,-0.03], p=0.04) and a borderline-significant lower stroke-volume-index (-5.0 ml/m², SMD -0.84, 95%CI [-1.77,0.08], p=0.07) could be observed. Data about the effect of GH replacement therapy highlighted a significant increase in left ventricular mass-index after treatment initiation (+3.7 g/m², 95%CI [1.6,5.7], p<0.01).

CONCLUSION

With respect to the left ventricle, our results confirmed those retrieved by echocardiographic studies. In addition, significant alterations were demonstrated also for the right ventricle, for which echocardiographic data are nearly absent. This supports the thesis of a biventricular cardiac involvement in patients with GHD, with a similar pattern of morphological and functional alterations in both ventricles.

Cardiovascular alterations in adult GH deficiency

There is a growing body of evidence indicating that patients with adult GH deficiency (GHD) are characterized by a cluster of traditional and emerging cardiovascular risk factors and markers, which can significantly increase their cardiovascular morbidity and mortality possibly linked to aberrations in GH status. Patients with adult GHD present multiple different cardiovascular abnormalities. In addition, cardiovascular risk in adult GHD is increased due to altered body composition, abnormal lipid profile, insulin resistance and impaired glucose metabolism. Cardiovascular risk factors can be reversed, at least partially, after GH replacement. However, evidence on the effects of GH replacement on cardiovascular events and mortality is too limited in adult GHD patients. Aim of this review is to provide an at-a-glance overview of the role of the GH/IGF-I on the cardiovascular system and the state of art of the effects of GH replacement on cardiovascular system.

The cardiovascular system in growth hormone excess and growth hormone deficiency

The clinical conditions associated with GH excess and GH deficiency (GHD) are known to be associated with an increased risk for the cardiovascular morbidity and mortality, suggesting that either an excess or a deficiency in GH and/or IGF-I is deleterious for cardiovascular system. In patients with acromegaly, chronic GH and IGF-I excess commonly causes a specific cardiomyopathy characterized by a concentric cardiac hypertrophy associated with diastolic dysfunction and, in later stages, with systolic dysfunction ending in heart failure if GH/IGF-I excess is not controlled. Abnormalities of cardiac rhythm and anomalies of cardiac valves can also occur. Moreover, the increased prevalence of cardiovascular risk factors, such as hypertension, diabetes mellitus, and insulin resistance, as well as dyslipidemia, confer an increased risk for vascular atherosclerosis. Successful control of the disease is accompanied by a decrease of the cardiac mass and improvement of cardiac function and an improvement in cardiovascular risk factors. In patients with hypopituitarism, GHD has been considered the under- lying factor of the increased mortality when appropriate standard replacement of the pituitary hormones deficiencies is given. Either childhood-onset or adulthood-onset GHD are characterized by a cluster of abnormalities associated with an increased cardiovascular risk, including altered body composition, unfavorable lipid profile, insulin resistance, endothelial dysfunction and vascular atherosclerosis, a decrease in cardiac mass together with an impairment of systolic function mainly after exercise. Treatment with recombinant GH in patients with GHD is followed by an improvement of the cardiovascular risk factors and an increase in cardiac mass together with an improvement in cardiac performance. In conclusion, acromegaly and GHD are associated with an increased risk for cardiovascular morbidity and mortality, but the control of GH/IGF-I secretion reverses cardiovascular abnormalities and restores the normal life expectancy.

Subtle alterations of cardiac performance in children with growth hormone deficiency: results of a two-year prospective, case-control study

BACKGROUND

GH-deficient (GHD) children have reduced left ventricular (LV) mass, but impairment of cardiac function has never been documented.

AIM

The aim of the study was to evaluate effects of GHD and GH therapy on cardiac function using load-dependent and load-independent indices of myocardial contractility.

PATIENTS AND METHODS

Echocardiography was performed in 24 GHD children at baseline and 1 and 2 yr after GH therapy and in 24 controls.

RESULTS

Compared with controls, GHD children at baseline had lower LV mass (LV mass/BSA 50.6 +/- 1.8 vs. 60.5 +/- 2.4 g/m(2); P < 0.002, and LV mass/H(2.7) 28.7 +/- 1.2 vs. 33.6 +/- 1.3 g/m(2.7); P < 0.009). Global systolic function was normal, with only a trend toward slight impairment of the fractional shortening (34.9 +/- 1.5 vs. 37.6 +/- 1.1%). However, subtle LV dysfunction was revealed by load-dependent and load-independent indices of myocardial contractility. In fact, GHD patients compared with controls showed lower rate-corrected mean velocity of circumferential fiber shortening (1.0 +/- 0.03 vs. 1.18 +/- 0.03 circ/sec; P = 0.0001) and stress shortening index (0.10 +/- 0.02 vs. 0.18 +/- 0.02; P < 0.007) and higher end-systolic stress (49.2 +/- 1.4 vs. 45.7 +/- 1.0 g/cm(2); P < 0.05). One year of GH treatment was associated with a significant improvement of cardiac size (LV mass/BSA 67.8 +/- 2.9 g/m(2); LV mass/H(2.7) 38.2 +/- 2.0 g/m(2.7); P < 0.0001 and P = 0.0003, respectively) and myocardial contractility (mean velocity of circumferential fiber shortening 1.2 +/- 0.04 circ/sec; P < 0.0002; stress shortening index 0.19 +/- 0.02; P < 0.003) and reduced afterload (end-systolic stress 43.9 +/- 1.4 g/cm(2); P < 0.03).

CONCLUSIONS

Our data indicate that GH deficiency is associated with abnormalities in morphology and function in not only adults but also children and further supports the beneficial effect of GH on the heart.

The GH-IGF-I axis and the cardiovascular system: clinical implications

BACKGROUND

GH and IGF-I affect cardiac structure and performance. In the general population, low IGF-I has been associated with higher prevalence of ischaemic heart disease and mortality. Both in GH deficiency (GHD) and excess life expectancy has been reported to be reduced because of cardiovascular disease.

OBJECTIVE

To review the role of the GH-IGF-I system on the cardiovascular system.

RESULTS

Recent epidemiological evidence suggests that serum IGF-I levels in the low-normal range are associated with increased risk of acute myocardial infarction, ischaemic heart disease, coronary and carotid artery atherosclerosis and stroke. This confirms previous findings in patients with acromegaly or with GH-deficiency showing cardiovascular impairment. Patients with either childhood- or adulthood-onset GHD have cardiovascular abnormalities such as reduced cardiac mass, diastolic filling and left ventricular response at peak exercise, increased intima-media thickness and endothelial dysfunction. These abnormalities can be reversed, at least partially, after GH replacement therapy. In contrast, in acromegaly chronic GH and IGF-I excess causes a specific cardiomyopathy: concentric cardiac hypertrophy (in more than two-thirds of the patients at diagnosis) associated to diastolic dysfunction is the most common finding. In later stages, impaired systolic function ending in heart failure can occur, if GH/IGF-I excess is not controlled. Abnormalities of cardiac rhythm and of cardiac valves can also occur. Successful control of acromegaly is accompanied by decrease of the left ventricular mass and improvement of cardiac function.

CONCLUSION

The cardiovascular system is a target organ for GH and IGF-I. Subtle dysfunction in the GH-IGF-I axis are correlated with increased prevalence of ischaemic heart disease. Acromegaly and GHD are associated with several abnormalities of the cardiovascular system and control of GH/IGF-I secretion reverses (or at least stops) cardiovascular abnormalities.

Exercise echocardiography reveals subclinical cardiac dysfunction in young adult survivors of childhood acute lymphoblastic leukemia

OBJECTIVE

Anthracyclines (AC) have contributed significantly to increased survival rate in acute lymphoblastic leukemia (ALL), although the use of these drugs is limited due to cardiotoxicity. The aim was to evaluate heart muscle function in asymptomatic adult survivors of ALL treated in early childhood in relation to the combined effects of AC and other potential cardiotoxic factors.

PROCEDURE

Twenty-three young adult ALL survivors who had all received treatment with median 120 (120-400) mg AC/m(2) before the onset of puberty were examined median 21 years after remission and compared with 12 healthy controls. Basal echocardiography including two-dimensional (2D) M-mode and Doppler examination was performed, followed by a maximal exercise stress test and stress echocardiography immediately after stress test and after 5 min recovery.

RESULTS

We found significant differences in systolic function between patients and controls at maximal exercise despite absence of reported symptoms from the patients. The most marked difference was in ejection fraction at stress 59.5% (32.6-81.1) and 77.3% (66.2-85.3), respectively (P < 0.00006). Ten out of 23 patients reduced their ejection fraction at stress compared with at rest; this was not found in any of the controls. Cardiovascular risk factors such as GH deficiency and a high proportion of trunk fat did not have an impact on cardiac function.

CONCLUSIONS

With very long follow up in a homogenous cohort of ALL survivors, we found subclinical cardiac dysfunction with exercise stress echocardiography even after low doses of AC.

Beginning to end: cardiovascular implications of growth hormone (GH) deficiency and GH therapy

Both growth hormone (GH) and insulin-like growth factor I (IGF-I) are involved in heart development and in maintenance of cardiac structure and performance. Cardiovascular disease has been reported to reduce life expectancy in both GH deficiency (GHD) and GH excess. Patients with GHD suffer from a cluster of abnormalities associated with increased cardiovascular risk, including abnormal body composition, unfavorable lipid profile, increased fibrinogen and C-reactive protein levels, insulin resistance, early atherosclerosis and endothelial dysfunction, and impaired left ventricular (LV) performance (i.e., reduced diastolic filling and impaired response to peak exercise). Long-term GH replacement therapy reverses most of these abnormalities. More consistently, GH replacement reduces body fat and visceral adipose tissue, reduces low-density lipoprotein cholesterol and triglyceride levels, and improves endothelial function. GH replacement also reduces intima media thickness at major arteries and improves LV performance, but these results have been observed only in small series of patients treated on a short-term basis. This review discusses the roles of GHD and GH replacement therapy in the development of cardiovascular disease.

The influence of growth hormone status on physical impairments, functional limitations, and health-related quality of life in adults

The availability of recombinant human GH and somatostatin analogs has resulted in widespread treatment for adults with GH deficiency (GHD) and those with GH excess (acromegaly). Despite being at opposite ends of the spectrum in terms of their GH/IGF-I axis, both of these populations experience overlapping somatic impairments. Adults with untreated GHD have low circulating levels of IGF-I that manifest as altered body composition with increased fat and reduced lean body and skeletal muscle mass. At the other end of the spectrum, adults with GH excess, who have elevated levels of IGF-I, also have altered body composition. Impairments that result from disorders of either GHD or GH excess are both associated with increased functional limitations, such as reduced ability to walk quickly for prolonged periods, and poorer health-related quality of life (HR-QoL). Adults with untreated GHD and GH excess both commonly complain of excessive fatigue that seems to be associated more with impaired aerobic than muscular performance. Several studies have documented that administration of GH or somatostatin analogs to adults with GHD or GH excess, respectively, ameliorates abnormal biochemical profile and the associated somatic impairments. However, whether these improvements translate into improved physical function in adults with GHD or GH excess remains largely unknown, and their impact on HR-QoL controversial. Review of placebo-controlled trials to date suggests that GH and somatostatin analogs have greater effects on gas exchange and aerobic performance than as anabolic agents on skeletal muscle mass and function. Future investigations should include dose-response studies to establish the optimal combination of pharmacological agents plus exercise required to improve not only biochemical markers but also physical function and HR-QoL in adults with GHD or GH excess.

Echocardiographic assessment of subclinical left ventricular eccentric hypertrophy in adult-onset GHD patients by geometric remodeling: an observational case-control study

BACKGROUND

Most patients with growth hormone deficiency (GHD) show high body mass index. Overweight subjects, but GHD patients, were demonstrated to have high left ventricular mass index (LVMi) and abnormal LV geometric remodeling. We sought to study these characteristics in a group of GHD patients, in an attempt to establish the BMI-independent role of GHD.

METHODS

Fifty-four patients, 28 F and 26 M, aged 45.9 +/- 13.1, with adult-onset GHD (pituitary adenomas 48.2%, empty sella 27.8%, pituitary inflammation 5.5%, cranio-pharyngioma 3.7%, not identified pathogenesis 14.8%) were enrolled. To minimize any possible interferences of BMI on the aim of this study, the control group included 20 age- and weight-matched healthy subjects. The LV geometry was identified by the relationship between LVMi (cut-off 125 g/m2) and relative wall thickness (cut-off 0.45) at echocardiography.

RESULTS

There was no significant between-group difference in resting cardiac morphology and function, nor when considering age-related discrepancy. The majority of patients had normal-low LVM/LVMi, but about one fourth of them showed higher values. These findings correlated to relatively high circulating IGF-1 and systolic blood pressure at rest. The main LV geometric pattern was eccentric hypertrophy in 22% of GHD population (26% of with severe GHD) and in 15% of controls (p = NS).

CONCLUSION

Though the lack of significant differences in resting LV morphology and function, about 25% of GHD patients showed high LVMi (consisting of eccentric hypertrophy), not dissimilarly to overweight controls. This finding, which prognostic role is well known in obese and hypertensive patients, is worthy to be investigated in GHD patients through wider controlled trials.

Influence of growth hormone on cardiovascular health and disease

Experimental and clinical studies indicate that growth hormone (GH) and insulin-like growth factor-1 (IGF-1) are involved in heart development. Impaired cardiovascular function, as recently demonstrated, could potentially reduce life expectancy both in GH deficiency (GHD) and excess. Patients with childhood- or adult-onset GHD may have both cardiac structural and functional abnormalities, i.e. reduced cardiac mass, reduced diastolic filling, and impaired left ventricular response to peak exercise. In addition, GHD patients may present with an increase in vascular intima-media thickness and a higher occurrence of atheromatous plaques that can further aggravate the hemodynamic conditions and contribute to the increased cardiovascular and cerebrovascular risk. However, some evidence has been provided to show that cardiovascular abnormalities can be partially reversed after somatropin (recombinant GH) therapy in patients with GHD. Recently, somatropin administration was shown to induce improvement in hemodynamics and clinical status in some patients with heart failure. Although these data need to be confirmed in more extensive studies, such promising results open new perspectives for somatropin therapy. The role of GH secretagogues in heart failure is still unknown.

The influence of growth hormone therapy on ultrasound myocardial tissue characterization in patients with childhood onset GH deficiency

BACKGROUND

In growth hormone deficiency (GHD), a reduction in left ventricular mass (LV-mass) and impairment of systolic function has been shown. In this study, we investigated the effects of 12 months of GH replacement therapy on cardiac structure and functional indices measured by echocardiographic techniques in adult patients with childhood onset GH deficiency.

METHODS

Sixteen patients (age 42.3+/-13.1 years, 10 males) were investigated before and after 12 months of GH treatment at a dose of 0.02 IU/kg/day (7 microg/kg/day). Echocardiography was performed including the ultrasound myocardial tissue characterization technique. We measured two parameters of the ultrasonic tissue characterization with integrated backscatter: the magnitude of the cardiac-cycle-dependent variation in integrated backscatter signals (CV-IBS) and the mean value of integrated backscatter signals calibrated by the pericardium (cal-IBS).

RESULTS

Left ventricular diameter and wall thickness did not change after GH treatment, although systolic increase in interventricular septum thickness (IVS%) and systolic increase in posterior wall thickness (PWT%) increased significantly (IVS% 52.2+/-31.9% vs. 67.3+/-30.4% and PWT% 48.7+/-20.2% vs. 58.0+/-17.7%, p<0.01 and p<0.01, respectively). Ejection fraction increased from 56.2+/-7.2% to 63.2+/-6.1% (p<0.01). LV-mass index did not change after GH treatment (78.4+/-22.1 vs. 81.9+/-21.1 g/m(2)). CV-IBS increased significantly after GH treatment (p<0.05), in both the interventricular septum and the left ventricular posterior wall (4.7+/-1.5 vs. 5.8+/-1.9 dB for the interventricular septum, 4.9+/-1.8 vs. 6.5+/-2.4 dB for the left ventricular posterior wall, p<0.05 and p<0.05, respectively). Cal-IBS also increased significantly after GH treatment (-23.5+/-4.1 vs.-21.8+/-4.2 dB for the interventricular septum, -23.0+/-4.4 vs. -21.8+/-4.3 dB for the left ventricular posterior wall, p<0.01 and p<0.05, respectively).

CONCLUSION

Twelve months GH treatment in adults with childhood onset GHD resulted in improvement of cardiac contractile performance. Observed changes in cal-IBS and CV-IBS suggest that GH treatment in this patient group can lead to a further somatic maturation of the heart, probably not accomplished previously.

The influence of growth hormone (GH) therapy on cardiac performance in patients with childhood onset GH deficiency

OBJECTIVE

There is accumulating evidence that growth hormone (GH) plays an important role in the maintenance of normal cardiac growth and function. Abnormalities in left ventricular diastolic function and impairment of systolic function have also been reported in patients with GHD. In this study, we investigated the effects of 12 months GH replacement therapy on cardiac functional indices measured by echocardiography, the ECG stress test and SPECT imaging.

DESIGN

Sixteen patients with childhood onset GHD (age 42.3+/-13.1 years, 10 males) were investigated before, and after, 12 months of GH treatment at a dosage of 0.02 IU/kg/day (7 microg/kg/day). The GH administration resulted in serum IGF-I levels within the normal range in all the patients. The following investigations were performed initially and after 12 months: electrocardiography, systolic and diastolic blood pressure, heart rate measurement, a complete Doppler-echocardiographic examination, treadmill exercise test and Technetium-99m sestamibi single-photon emission computer tomography (SPECT) imaging at rest and after exercise.

RESULTS

Echocardiography showed improvement in left ventricular systolic function after GH treatment. End-systolic volume fell from 29.9+/-12.4 to 24.4+/-6.9 ml (p<0.05) and the ejection fraction increased from 56.2+/-7.2% to 63.2+/-6,1% (p<0.01). Left ventricular diameter and wall thickness did not change after GH treatment, although systolic increase in interventricular septum thickness (IVS%) and systolic increase in posterior wall thickness (PWT%) increased significantly (IVS% 52.2+/-31.9% vs. 67.3+/-30.4% and PWT% 48.7+/-20.2% vs. 58.0+/-17.7%, p<0.01, p<0.01, respectively). Contractile function, measured at midwall level, improved as left ventricular midwall fractional shortening (MWS) increased (16.11+/-6.55 vs. 23.30+/-5.89 %, p<0.01) and stress-corrected MWS increased between the examinations performed before and after 12 months of GH treatment (90.97+/-36.66 vs. 133.10+/-32.84 %, p<0.01). Diastolic function did not change, as assessed by early diastolic flow (E), diastolic flow secondary to atrial contraction (A), or the E/A ratio. The LV-mass index did not change significantly after GH treatment (78.4+/-22.1 vs. 81.9+/-21.1g/m(2)). After 12 months of GH treatment the myocardial performance index (MPI) decreased significantly from 0.483+/-0.146 at baseline to 0.410+/-0.086 at the end of the study (p<0.05). There was a trend towards an increase in exercise duration and capacity after GH treatment but the differences did not reach levels of statistical significance. SPECT imaging basally and after 12 months showed normal myocardial perfusion at rest and after exercise in all the patients. In conclusion, GH replacement therapy in adults with GHD demonstrated the beneficial effects on cardiac functions.

The role of growth hormone replacement in a growth hormone deficient patient with underlying cardiomyopathy and severe congestive heart failure

It has been reported that growth hormone (GH) deficiency induced cardiomyopathy responds to growth hormone replacement therapy. We describe the case of a middle-aged male with cardiomyopathic heart failure and growth hormone deficiency of the adult secondary to surgical panhypopituitarism. We demonstrate clinical and hemodynamic improvement of cardiac function with growth hormone replacement therapy despite underlying structural heart disease.

The severity of growth hormone deficiency correlates with the severity of cardiac impairment in 100 adult patients with hypopituitarism: an observational, case-control study

In 100 patients with hypopituitarism and 80 sex- and age-matched healthy subjects, we correlated the severity of cardiac impairment to the severity of GH deficiency (GHD). By the GH peak after arginine plus GHRH test (normal > 16.5 microg/liter), the patients were classified as severe GHD (n = 56), partial GHD (n = 27), and non-GHD (n = 17). Compared with controls, decreased left ventricular ejection fraction at rest was found only in severe GHD patients (55.0 +/- 8.8 vs. 63.4 +/- 4.5%, P < 0.001); decreased left ventricular ejection fraction response on effort in severe (-4.6 +/- 17.4 vs. 15.2 +/- 9.1%, P < 0.001) and partial GHD patients (3.6 +/- 6.6 vs. 14.6 +/- 8.3%, P < 0.001); decreased diastolic filling at rest in severe (2.53 +/- 0.68 vs. 3.01 +/- 0.48 end-diastolic volume per second, P < 0.001) and partial GHD (2.61 +/- 0.45 vs. 2.89 +/- 0.54 end-diastolic volume per second, P = 0.004) patients; and decreased exercise duration and capacity in all the patient groups. A normal systolic performance on effort was found in 21.4% of severe GHD, 55.6% of partial GHD, all non-GHD, and 93.7% of controls. A normal diastolic filling at rest was found in 57.1% of severe GHD, 74.1% of partial GHD, 76.5% of non-GHD, and 90% of controls. In conclusion, cardiac performance is correlated with the GH status because significant impairment was found in patients with severe and partial GHD but not in non-GHD hypopituitary patients.

Cardiovascular Effects of Growth Hormone Treatment: Potential Risks and Benefits

Growth hormone (GH) and insulin-like growth factor-I are involved in heart development and in maintaining cardiac structure and performance. Cardiovascular disease has been reported to reduce life expectancy both in GH deficiency (GHD) and in GH excess. Patients with GHD suffer from abnormalities of left ventricular performance, i.e. reduced diastolic filling and impaired response to peak exercise. Patients with GHD also have increased intima-media thickness at the common carotid arteries, associated with a higher occurrence of atherosclerotic plaques, which may further aggravate the haemodynamic conditions. This may contribute to increased cardiovascular and cerebrovascular risk. These cardiovascular abnormalities can be reversed, at least partially, with GH replacement therapy. In recent years, GH therapy has been used to increase cardiac mass in ischaemic or dilated cardiomyopathy, but the results have produced contradictory data.

Cardiac Abnormalities in Acromegaly

Cardiovascular disease is claimed to be one of the most severe complications of acromegaly, contributing significantly to mortality in this disease. In fact, an excess of growth hormone (GH) and insulin-like growth factor 1 (IGF-I) causes a specific derangement of cardiomyocytes, leading to abnormalities in cardiac muscle structure and function, inducing a specific cardiomyopathy. In the early phase of acromegaly the excess of GH and IGF-I induces a hyperkinetic syndrome, characterized by increased heart rate and increased systolic output. Concentric hypertrophy is the most common feature of cardiac involvement in acromegaly, found in more than two thirds of patients at diagnosis. This abnormality is commonly associated with diastolic dysfunction and eventually with impaired systolic function ending in heart failure, if the GH/IGF-I excess is left untreated. In addition, abnormalities of cardiac rhythm and of heart valves have also been described in acromegaly. The coexistence of other complications, such as arterial hypertension and diabetes mellitus, aggravates acromegalic cardiomyopathy. Successful control of acromegaly induces a decrease in left ventricular mass and an improvement in diastolic function, while the effects of GH/IGF-I suppression on systolic function are more variable. However, since cardiovascular alterations in young patients with short disease duration are milder than in those with longer disease duration, it is likely to be easier to reverse and/or arrest acromegalic cardiomyopathy in young patients with early-onset disease. In conclusion, careful assessments of cardiac function, morphology, and activity are required in patients with acromegaly. An early diagnosis and prompt effective treatment are important in order to reverse acromegalic cardiomyopathy.

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.

Cardiac effects of growth hormone in adults with growth hormone deficiency: a meta-analysis

BACKGROUND

Growth hormone (GH) treatment may improve morphological and functional cardiac parameters in adults with GH deficiency (GHD). However, clinical trials reported to date involved few patients and yielded variable effects.

METHODS AND RESULTS

We systematically reviewed blinded, placebo-controlled, randomized clinical trials of GH treatment in adults with GHD and open studies in patients with GHD before and after GH treatment, evaluating the effects of GH on cardiac parameters assessed by echocardiography. Sixteen trials (9 blinded and 7 open), involving a total of 468 patients, were identified in 3 bibliographic databases. GH dosage, duration of treatment, and study populations varied among the studies. We conducted a combined analysis of effects on left ventricular mass (LVM), interventricular septum thickness (IVS), left ventricular posterior wall (LVPW), left ventricular end-systolic (LVESD) and diastolic (LVEDD) diameters, stroke volume, E/A ratio, isovolumic relaxation time (IRT), and fractional shortening. Overall effect size was used to evaluate significance, and weighted mean difference between GH and control was given to appreciate size of the effect. GH treatment was associated with a significant increase in LVM: +10.8 (SD: 9.3) g (P=0.02); IVS: +0.28 (0.38) mm (P<0.001), LVPW: 0.98 (0.22) mm (P=0.05), LVEDD: +1.34 (1.13) mm (P<0.001), and stroke volume: +10.3 (8.7) mL (P<0.001). A trend toward a difference in fractional shortening was observed: +1.1 (1.1)% (P=0.06). Overall effect sizes were not significant for LVESD, E/A, and IRT.

CONCLUSIONS

GH treatment is associated with a significant positive effect on LVM, IVS, LVPW, LVEDD, and stroke volume, as assessed by echocardiography, in adults with GHD.

Three weekly injections (TWI) of low-dose growth hormone (GH) restore low normal circulating IGF-I concentrations and reverse cardiac abnormalities associated with adult onset GH deficiency (GHD)

GH replacement therapy given 3 times weekly (TWI) and adjusted to allow serum IGF-I concentrations in the mid-normal range for sex and age has been shown to be as effective as the daily regimen in improving lipid profile, body composition, bone mass and turnover in adult GH deficient (GHD) patients. Only one study has investigated so far the short-term (6 months) effect of a fixed weight-based TWI dosing schedule on heart structure and function in childhood onset (CO) GHD patients, whereas such a schedule in adult onset (AO) GHD patients has not been studied as yet. Aim of this study was to investigate whether a 1-yr low-dose titrated TWI GH-replacement regimen aimed at achieving and maintaining IGF-I levels within the low normal limits for age and sex is able to affect cardiovascular and heart parameters in a group of AO GHD patients. Eight adult patients (4 women and 4 men, age 35.8 +/- 3.37 yr, body mass index, BMI, 28.7 +/- 2.62 kg/m2) with AO GHD were included in the study, along with 10 healthy subjects, matched for age, sex, BMI and physical activity (6 women and 4 men, age 35.2 +/- 4.05 yr, BMI 28.4 +/- 2.34 kg/m2). M- and B- mode ecocardiography and pulsed doppler examination of transmitral flow were performed in GHD patients at baseline and after 3 and 12 months of GH therapy (mean GH dose 6.7 +/- 0.8 microg/kg/day given thrice a week), while normal subjects were studied once. Treatment with GH for 1 yr induced a significant increase in left ventricular (LV) diastolic and systolic volumes (+11.1 and +16.5%, respectively). Systolic LV posterior wall thickness and LV mass were increased (+10.2 and +7.7%, respectively) by GH administration. Systemic vascular resistance was significantly decreased by 1-yr GH therapy (-13.8% after 1 yr), while stroke volume, cardiac output and cardiac index were increased (+9.4, +11.6 and + 11.9%, respectively). LV end-systolic stress was decreased at the end of GH therapy (-11.2%). E and A wave, significantly reduced at baseline, were increased by 1 yr of GH therapy (+23.3% and +28.1%, respectively); likewise, the abnormally high E peak deceleration time was partially reversed by GH administration (-10.7%). Our study, though conducted in a small sample size, demonstrates that a TWI GH treatment schedule is able to reverse the cardiovascular abnormalities in AO GHD patients and to improve body composition and lipid profile. The maintenance of circulating IGF-I concentrations within the low normal range allows to avoid most of the side-effects reported with higher GH doses while being cost-effective and improving the patient's compliance.

Long-term growth hormone replacement therapy in hypopituitary adults

Growth hormone deficiency (GHD) in the adult has now been fully recognised as a clinical entity characterised by abnormal body composition, osteopenia, impaired quality of life, cardiac dysfunction and an adverse lipid profile. While short-term studies of GH replacement have demonstrated irrefutably a favourable effect on all if not most features of GHD, data on long-term administration spanning more than 2 years are still scarce. Experience of GH replacement up to 5 to 10 years indicate that the beneficial effects on body composition, predominantly a decrease in body fat and an increase in lean mass, is maintained during treatment. Long-term GH therapy also increases muscle strength and exercise performance. All data, with one exception, are consistent with a significant increase in bone mass during prolonged GH therapy. The most distinct effect on bone was observed in the worst affected individuals and in males. Improvement in quality of life is documented shortly after initiation of GH replacement and is maintained during long-term studies. This may explain the reduction in days of sick leave seen during GH therapy. The beneficial effect on cardiovascular risk factors is sustained over a prolonged period of time, revealing a reduction in intima wall thickness, and an improvement in serum lipid levels and clotting parameters. The increase in lipoprotein(a) levels with GH therapy in some studies may be disturbing, but difficulties in measuring this parameter and inconsistencies between the different studies makes it difficult to estimate its real impact. No data are yet available to show that GH replacement will normalise or even improve mortality rate and fracture rate. Adverse events associated with GH replacement therapy are mainly secondary to fluid retention as a result of excess dose administration. This can be adequately prevented by monitoring GH replacement according to serum insulin-like growth factor (IGF)-I levels. From what is currently known, GH replacement does not increase the prevalence of diabetes mellitus, and does not induce new neoplasms or recurrence of the primary brain tumour; however, longer follow-up studies are needed to provide definitive answers. In conclusion, it appears not only that long-term GH replacement therapy in adults with GHD is a procedure that can be safely used, but that GH replacement should be considered as a possible life-long therapy in order to maintain its benefits.

Childhood-onset growth hormone (GH) deficiency in adult life

Over the last decade GH replacement therapy for adults has progressed in status from research study to a mainstream clinical indication. An area ripe for further research, however, is the difference between adults who developed GHD before and after completion of growth and puberty. That differences exist, not only in aetiology, but also in phenotype and response to GH therapy is clear. However, whether these differences are intrinsic to the timing of onset of GHD, or related to secondary factors including the method of assessment or dose of GH employed is uncertain. This chapter discusses the current state of knowledge in this area and poses further questions, not only for the researcher attempting to understand the mechanisms underlying these differences, but also for the physician seeking to ameliorate the impact of GHD in patients who acquired GHD in childhood.

Human growth hormone replacement in adult hypopituitary patients: long-term effects on body composition and lipid status--3-year results from the HypoCCS Database

The Hypopituitary Control and Complications Study is an international surveillance study evaluating efficacy and safety of GH therapy of adult GH-deficient patients in clinical practice. The present report examined baseline data from 1,123 adult onset (AO) and 362 childhood onset (CO) patients, as well as efficacy in 242 patients who had completed 3 yr of GH treatment. At study entry, mean height, body mass index, waist to hip ratio, and lean body mass were significantly (P < 0.001 for each) lower in CO compared with AO patients. After 3 yr on GH, lean body mass was significantly increased in AO males and females and CO males but not CO females, whereas fat mass was significantly decreased in AO males only. Serum total cholesterol was decreased in females (-0.32 +/- 1.00 mmol/liter; P = 0.045) and males (-0.36 +/- 0.96 mmol/liter; P = 0.004). High-density lipoprotein (HDL) cholesterol was increased for females (0.10 +/- 0.26 mmol/liter; P = 0.026) and males (0.10 +/- 0.34 mmol/liter; P = 0.022). The low-density lipoprotein/HDL ratio was decreased in AO males (-0.93 +/- 2.00; P = 0.003), AO females (-0.65 +/- 0.74; P < 0.001), and CO females (-0.69 +/- 0.76; P = 0.038), but the decrease in CO males was not significant (-0.84 +/- 2.85; P = 0.273). In AO patients, lean body mass increase from baseline was greatest in the those younger than 40 yr old, less but still significant in the middle group (40-60 yr) and unchanged in older (>60 yr) patients; conversely, decreases in the low-density lipoprotein/HDL ratio were small and not significant in the younger patients but greater and significant in the middle and older age groups. During the 3-yr treatment, 114 (7.7%) patients discontinued, including 9 (0.6%) for tumor recurrences, 9 (0.6%) for neoplasia, and 9 (0.6%) for side effects. Therefore, these observational data showed significant long-term efficacy of adult GH replacement therapy on body composition and lipid profiles and indicate that age is an important predictor of response.

The cardiovascular risk of adult GH deficiency (GHD) improved after GH replacement and worsened in untreated GHD: a 12-month prospective study

Increased cardiovascular morbidity and mortality were reported in GH deficiency (GHD), and GH replacement can ameliorate cardiac abnormalities of adult GHD patients. To test the potential progression of untreated GHD on the cardiovascular risk and cardiac function, cardiovascular risk factors, cardiac size, and performance were prospectively evaluated in 15 GHD patients (age, 18-56 yr) who were treated with recombinant GH at the dose of 0.15-1.0 mg/d, 15 GHD patients (age, 18-56 yr) who refused GH replacement, and 30 healthy subjects (age, 18-53 yr). Electrocardiogram, systolic and diastolic blood pressure, and heart rate measurement, serum IGF-I, total cholesterol, low- and high-density lipoprotein (LDL, HDL) cholesterol, triglycerides, and fibrinogen level assay, echocardiography, and equilibrium radionuclide angiography were performed basally and after 12 months. At study entry, low IGF-I levels, unfavorable lipid profile, and inadequate cardiac and physical performance were found in GHD patients compared with controls. After 12 months of GH treatment, IGF-I levels normalized; HDL-cholesterol levels, left ventricular (LV) mass index (LVMi), left ventricular ejection fraction (LVEF) at peak exercise, peak filling rate, exercise duration and capacity significantly increased; total- and LDL-cholesterol levels significantly decreased. After 12 months in GH-untreated GHD patients, IGF-I levels remained stable, and HDL-cholesterol levels, LVEF both at rest and at peak exercise, and exercise capacity were further reduced; total- and LDL-cholesterol levels increased slightly. LVEF at rest and its response at peak exercise normalized in 60 and 53.3%, respectively, of GH-treated patients and in none of the GH-untreated patients. In conclusion, 12 months of GH replacement normalized IGF-I and improved lipid profile and cardiac performance in adult GHD patients. A similar period of GH deprivation induced a further impairment of lipid profile and cardiac performance. This finding strongly supports the need of GH replacement in adult GHD patients.

Insulin-like growth factor I and II preserve myocardial structure in postinfarct swine

BACKGROUND

Insulin-like growth factors (IGF) I and II improve myocardial function after coronary occlusion in different animal models.

OBJECTIVES

To investigate the mechanism of improved myocardial function after administration of IGF-I or IGF-II in acute myocardial infarction.

METHODS

Female pigs (mean (SD) weight 25 (5) kg) were subjected to acute myocardial infarction by microembolisation with 75-150 micrometer affigel blue beads. The beads contained and slowly released 150 microgram/pig of IGF-I (n = 6), IGF-II (n = 6), or pig albumin (n = 6). Echocardiography, perfusion imaging, and haemodynamic measurements were performed before infarction and during four weeks after infarction. Regional wall motion of different left ventricular segments was scored semiquantitatively on the basis of a three point scoring system, from normal = 0 to dyskinesia = 3. Serum cardiac troponin I concentration was measured before, immediately after, and three hours after the infarct. Excised hearts were analysed for actin, desmin, blood vessel density, and DNA laddering within the infarct, border, and normal myocardial areas.

RESULTS

Myocardial function of the infarct related area improved significantly during the four weeks of follow up in both the IGF groups (p = 0.01). Myocardial perfusion, heart rate, and blood pressure were similar in all the animals during the study. Treated animals had lower serum cardiac troponin I concentration (p = 0.001), more actin in the border area (p = 0.01) and infarct area (p = 0.0001), and reduced DNA laddering in the infarct area compared with the controls (p < 0.05). IGF groups had more blood vessels in the border area (p = 0.04) and the infarct area (p = 0.003).

CONCLUSIONS

Both types of IGF improved myocardial function and the improvement was associated with preservation of myocardial structure. IGF-I was more effective than IGF-II.

Growth hormone therapy in adults

The importance of growth hormone (GH) deficiency in adults became evident 10 to 15 years ago, when the first clinical studies on GH replacement therapy in adults were published. Since then, a number of studies have been reported showing that GH replacement therapy can improve this condition. Adult GH deficiency (GHD) is now recognized as a specific clinical syndrome and the first reports of long-term use of GH (up to 10 years) are now being published. The aim of this paper was to review the accumulated data on the various clinical aspects of adult GHD.

The influence of growth hormone replacement on heart rate variability in adults with growth hormone deficiency

OBJECTIVE

Growth hormone (GH) deficiency is associated with increased cardiovascular morbidity and mortality. Abnormalities in heart rate variability (HRV), a surrogate marker of cardiac autonomic tone, have also been found in untreated growth hormone deficient (GHD) patients. Similar abnormalities have been found in patients with complications postmyocardial infarction.

DESIGN AND MEASUREMENTS

This study was designed to investigate whether GH treatment leads to normalization of cardiac autonomic tone. HRV measurements were obtained from 15 minute resting ECG recordings in 11 untreated adult GHD patients (7 females; mean age 39.2 years), 10 GHD patients (6 females; mean age 46.2 years) reCENving GH replacement (mean duration, 52.7 months) and 12 healthy controls (7 females; mean age 44.6 +/- 2.9 years) who were all of similar age, weight and BMI. The untreated GHD patients were then commenced on GH and HRV measurements repeated after 3 and 6 months of treatment.

RESULTS

In accord with our previous findings, HRV analysis using Fast Fourier Transform (FFT) showed a distinct pattern of abnormality in GHD patients compared with controls. Specifically, there was an increase in nHF power (P = 0.04) and a reduction in nLF power (P = 0.04) (representing parasympathetic and sympathetic activity, respectively), a reduction in nVLF power (P = 0.03) and a 50% reduction in LF/HF ratio (P = 0.02) (a measure of sympathovagal balance) in GHD patients when compared with controls. HRV results in patients who have been on long-term GH replacement were indistinguishable from controls. After 3 months GH replacement in the untreated GHD patient group, nVLF power had increased by 28% (P = 0.03) at 3 months and this was sustained at 6 months. However, no significant changes in LF and HF power were seen.

CONCLUSIONS

These results suggest that abnormalities of the cardiac autonomic system in GHD patients may be correctable. Longer duration of prospective follow-up will be required to determine at what time point improvements in the other frequency bands occur.

[The Influence of the growth hormone in the profile of blood pressure. Results in adult patients with deficiency in this hormone]

INTRODUCTION AND OBJECTIVES

There is an increasing interest in the relationship between the growth hormone (GH) and the heart since the GH has an important inotropic effect and its use has been tested in patients with severe systolic dysfunction. However, cardiovascular diseases are the main cause of increased morbimortality observed in patients with acromegaly. Growth hormone deficiency has been related to different clinical findings depending on the age of onset. Recent studies have demonstrated that GH deficiency in adults is associated with alterations in blood pressure. The aim of our study was to assess the influence of GH in blood pressure.

PATIENTS AND METHODS

We studied 14 adult patients with GH deficiency and 15 healthy subjects, matched for sex and age. The diagnosis of GH deficiency was based on GH response to intravenous insulin tolerance test < 5 ng/ml and IGF-1 levels lower than the normal limit for each age group. In all the patients 24-hour Holter blood pressure monitorization was performed in addition to a treadmill test and echographic evaluation.

RESULTS

All patients showed normal systolic and diastolic function in the echocardiographic study. Only one patient had an increased left ventricular mass. Blood pressure was lower in the patients than in the control subjects (p < 0.05). Moreover, the difference remained significant when analysis was based on the time of day. However, the patients showed normal blood pressure response to the effort test with a mean increase of 60%. The length of the exercise on the treadmill test was shorter in the subgroup of GH deficient patients.

CONCLUSIONS

Lower systolic blood pressure was observed in GH deficiency patients. The patients studied did not show structural heart alterations. Blood pressure and chronotrophic response to the effort test were similar in both groups.

Growth hormone and the heart

Impaired cardiovascular function has recently been demonstrated to potentially reduce life expectancy both in GH deficiency and excess. Experimental and clinical studies have supported the evidence that GH and IGF-I are implicated in cardiac development. In most patients with acromegaly a specific cardiomyopathy, characterized by myocardial hypertrophy with interstitial fibrosis, lympho-mononuclear infiltration and areas of monocyte necrosis, results in biventricular concentric hypertrophy. In contrast, patients with childhood or adulthood-onset GH deficiency (GHD) may suffer both from structural cardiac abnormalities, such as narrowing of cardiac walls, and functional impairment, that combine to reduce diastolic filling and impair left ventricular response to peak exercise. In addition, GHD patients may have an increase in vascular intima-media thickness and a higher occurrence of atheromatous plaques, that can further aggravate the haemodynamic conditions and contribute to increased cardiovascular and cerebrovascular risk. However, several lines of evidence have suggested that the cardiovascular abnormalities can be partially reversed by suppressing GH and IGF-I levels in acromegaly or after GH replacement therapy in GHD patients. Recently, much attention has been focussed on the ability of GH to increase cardiac mass suggesting its possible use in the treatment of chronic nonendocrine heart failure. In fact, GH administration can induce an improvement in haemodynamic and clinical status in some patients. Although these data need to be confirmed in more extensive studies, such promising results seem to open new perspectives for GH treatment in humans.