Alterations of haemostatic and fibrinolytic markers in adult patients with growth hormone deficiency and with acromegaly

An Overview of Cardiovascular Risk in Pituitary Disorders

Cardiovascular comorbidities owing to hormonal excess or deficiency are the main cause of mortality in patients with pituitary disorders. In patients with Cushing's Disease, there is an increased prevalence of cardiovascular diseases and/or risk factors including visceral obesity, insulin resistance, atherosclerosis, arterial hypertension, dyslipidaemia, hypercoagulability as well as structural and functional changes in the heart, like cardiac hypertrophy and left ventricle (LV) dysfunction. Notably, these demonstrate limited reversibility even after remission. Furthermore, patients with acromegaly may manifest insulin resistance but also structural and functional heart changes, also known as "acromegalic cardiomyopathy". Patients with prolactinomas demonstrate an aggravation of metabolic parameters, obesity, dysregulation of glucose and lipid metabolism as well as endothelial dysfunction. Hypopituitarism and conventional hormonal replacement therapy may also contribute to an unhealthy metabolic status, which promotes atherosclerosis and may lead to premature mortality. This review discusses the literature on cardiovascular risk in patients with pituitary disorders to increase physician awareness regarding this aspect of management in patients with pituitary disorders.

Morbidities and mortality among hospitalized patients with hypopituitarism: Prevalence, causes and management

Hypopituitarism is a highly heterogeneous multisystem disorder that can have a major impact on long-term morbidity and mortality, but even more so during acute medical conditions requiring hospitalization. Recent studies suggest a significant in-hospital burden with prolonged length of stay, increased rate of intensive care unit (ICU) admission, and initiation of mechanical ventilation - all of which may lead to an increased risk of in-hospital mortality. On the one hand, patients with hypopituitarism are often burdened by metabolic complications, including obesity, hypertension, dyslipidemia, and hyperglycemia, which alone, or in combination, are known to significantly alter relevant physiological mechanisms, including metabolism, innate and adaptive immune responses, coagulation, and wound healing, thereby contributing to adverse in-hospital outcomes. On the other hand, depending on the extent and the number of pituitary hormone deficiencies, early recognition of hormone deficiencies and appropriate management and replacement strategy within a well-organized multidisciplinary team are even stronger determinants of short-term outcomes during acute hospitalization in this vulnerable patient population. This review aims to provide an up-to-date summary of recent advances in pathophysiologic understanding, clinical implications, and recommendations for optimized multidisciplinary management of hospitalized patients with hypopituitarism.

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.

Molecular and cellular pathways contributing to brain aging

Aging is the leading risk factor for several age-associated diseases such as neurodegenerative diseases. Understanding the biology of aging mechanisms is essential to the pursuit of brain health. In this regard, brain aging is defined by a gradual decrease in neurophysiological functions, impaired adaptive neuroplasticity, dysregulation of neuronal Ca2+ homeostasis, neuroinflammation, and oxidatively modified molecules and organelles. Numerous pathways lead to brain aging, including increased oxidative stress, inflammation, disturbances in energy metabolism such as deregulated autophagy, mitochondrial dysfunction, and IGF-1, mTOR, ROS, AMPK, SIRTs, and p53 as central modulators of the metabolic control, connecting aging to the pathways, which lead to neurodegenerative disorders. Also, calorie restriction (CR), physical exercise, and mental activities can extend lifespan and increase nervous system resistance to age-associated neurodegenerative diseases. The neuroprotective effect of CR involves increased protection against ROS generation, maintenance of cellular Ca2+ homeostasis, and inhibition of apoptosis. The recent evidence about the modem molecular and cellular methods in neurobiology to brain aging is exhibiting a significant potential in brain cells for adaptation to aging and resistance to neurodegenerative disorders.

Acromegaly, inflammation and cardiovascular disease: a review

Acromegaly is characterized by Growth Hormone (GH) and Insulin-like Growth Factor 1 (IGF-1) excess. Uncontrolled acromegaly is associated with a strongly increased risk of cardiovascular disease (CVD), and numerous cardiovascular risk factors remain present after remission. GH and IGF-1 have numerous effects on the immune and cardiovascular system. Since endothelial damage and systemic inflammation are strongly linked to the development of CVD, and have been suggested to be present in both controlled as uncontrolled acromegaly, they may explain the presence of both micro- and macrovascular dysfunction in these patients. In addition, these changes seem to be only partially reversible after remission, as illustrated by the often reported presence of endothelial dysfunction and microvascular damage in controlled acromegaly. Previous studies suggest that insulin resistance, oxidative stress, and endothelial dysfunction are involved in the development of CVD in acromegaly. Not surprisingly, these processes are associated with systemic inflammation and respond to GH/IGF-1 normalizing treatment.

The haemostatic system in acromegaly: a single-centre case-control study

PURPOSE

Although the mortality from acromegaly is due in most cases to an increased cardiovascular risk, no study has globally evaluated the haemostatic balance in acromegaly to ascertain the presence of hypercoagulability. We endeavoured to assess the overall coagulation profile in patients with acromegaly using both traditional and global coagulation assays.

METHODS

Consecutive outpatients with a diagnosis of acromegaly were enrolled and matched with healthy subjects. Whole blood thromboelastometry and impedance aggregometry, procoagulant, anticoagulant and fibrinolytic factors, as well as thrombin-generation assay and circulating endothelium-derived microvesicles were measured.

RESULTS

Forty patients (M/F 14/26, median age 59 years) with either new diagnosis (naïve, 14 cases) or treated acromegaly (26 cases) were enrolled in this study. Median time from diagnosis was 11 years. Levels of factor VIII and fibrinogen were significantly higher in acromegalic patients vs. controls (p = 0.029 and < 0.003, respectively). Overall, thromboelastometry parameters showed a faster coagulation formation with a more stable clot. Acromegaly patients showed significantly higher endogenous thrombin potential [ETP] and thrombin peak compared to controls (p = 0.016 and p < 0.001, respectively). ETP remained significantly higher (p < 0.001) when thrombomodulin was added. Endothelial-derived microvesicles were significantly higher in acromegaly patients than controls (52 [40.5-67] MVs/µL and 30 [18-80] MVs/µL, p = 0.03). Patients with untreated (naïve) acromegaly showed significantly reduced ETP with and without thrombomodulin vs. patients with treated acromegaly (p = 0.01).

CONCLUSION

Hypercoagulability in acromegaly is mainly due to higher levels of fibrinogen, factor VIII and thrombin generation, and appears to be more linked to the chronic phase of the disease.

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.

MEAN PLATELET VOLUME AND PLATELET FUNCTION ANALYSIS IN ACROMEGALIC PATIENTS BEFORE AND AFTER TREATMENT

Objective

Mean platelet volume (MPV) and platelet function analysis have been studied before in acromegaly, but the effect of treatment on both parameters has not been evaluated. We aimed to investigate MPV and platelet function analysis in acromegalic patients after six-months of treatment.

Methods

Forty patients with active acromegaly and 36 healthy subjects were included in the study. Plasma glucose and lipids, fibrinogen, GH, IGF-1 levels, MPV and platelet function analysis were measured. All patients with acromegaly were re-evaluated six months after treatment.

Results

Fasting blood glucose (FBG), GH, IGF-1, fibrinogen levels and MPV values were significantly higher in acromegalic group compared with the control. Platelet function was enhanced significantly (pcol-ADP: 0.002, pcolepinephrine: 0.002). After 6 months of treatment FBG, serum GH, IGF-1, fibrinogen and MPV decreased and collagen/ADP- and collagen/epinephrine-closure times (CT) were increased. Acromegalic patients that were in remission with long-acting SSA after surgery had significantly higher fibrinogen levels and MPV and decreased collagen/epinephrine-CT with respect to the controls (pfibrinogen: 0.001, pMPV: 0.026, pcol-epinephrine: 0.037).

Conclusion

Acromegaly was associated with increased MPV and enhanced platelet activity. Although growth hormone hypersecretion was controlled by surgery and medical treatment, these parameters did not improve - indicating a still increased risk for cardiovascular events.

Coagulation parameters and platelet function analysis in patients with acromegaly

OBJECTIVE

Acromegaly is associated with increased cardiovascular morbidity and mortality. The data about the evaluation of coagulation and fibrinolysis in acromegalic patients are very limited and to our knowledge, platelet function analysis has never been investigated. So, we aimed to investigate the levels of protein C, protein S, fibrinogen, antithrombin 3 and platelet function analysis in patients with acromegaly.

METHODS

Thirty-nine patients with active acromegaly and 35 healthy subjects were included in the study. Plasma glucose and lipid profile, fibrinogen levels, GH and IGF-1 levels and protein C, protein S and antithrombin III activities were measured in all study subjects. Also, platelet function analysis was evaluated with collagen/ADP and collagen-epinephrine-closure times.

RESULTS

Demographic characteristics of the patient and the control were similar. As expected, fasting blood glucose levels and serum GH and IGF-1 levels were significantly higher in the patient group compared with the control group (pglc: 0.002, pGH: 0.006, pIGF-1: 0.001, respectively). But lipid parameters were similar between the two groups. While serum fibrinogen and antithrombin III levels were found to be significantly higher in acromegaly group (p fibrinogen: 0.005 and pantithrombin III: 0.001), protein S and protein C activity values were significantly lower in the patient group (p protein S: 0.001, p protein C: 0.001). Also significantly enhanced platelet function (measured by collagen/ADP- and collagen/epinephrine-closure times) was demonstrated in acromegaly (p col-ADP: 0.002, p col-epinephrine: 0.002). The results did not change, when we excluded six patients with type 2 diabetes in the acromegaly group. There was a negative correlation between serum GH levels and protein S (r: -0.25, p: 0.04)) and protein C (r: -0.26, p: 0.04) values. Likewise, there was a negative correlation between IGF-1 levels and protein C values (r: -0.39, p: 0.002), protein S values (r: -0.39, p: 0.001), collagen/ADP-closure times (r: -0.28, p: 0.02) and collagen/epinephrine-closure times (r:-0.26, p: 0.04). Also, we observed a positive correlation between IGF-1 levels and fibrinogen levels (r: 0.31, p: 0.01).

CONCLUSION

Acromegaly was found to be associated with increased tendency to coagulation and enhanced platelet activity. This hypercoagulable state might increase the risk for cardiovascular and cerebrovascular events in acromegaly.

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.

Endothelin-1-induced focal cerebral ischemia in the growth hormone/IGF-1 deficient Lewis Dwarf rat

Aging is a major risk factor for cerebrovascular disease. Growth hormone (GH) and its anabolic mediator, insulin-like growth factor (IGF)-1, decrease with advancing age and this decline has been shown to promote vascular dysfunction. In addition, lower GH/IGF-1 levels are associated with higher stroke mortality in humans. These results suggest that decreased GH/IGF-1 level is an important factor in increased risk of cerebrovascular diseases. This study was designed to assess whether GH/IGF-1-deficiency influences the outcome of cerebral ischemia. We found that endothelin-1-induced middle cerebral artery occlusion resulted in a modest but nonsignificant decrease in cerebral infarct size in GH/IGF-1 deficient dw/dw rats compared with control heterozygous littermates and dw/dw rats with early-life GH treatment. Expression of endothelin receptors and endothelin-1-induced constriction of the middle cerebral arteries were similar in the three experimental groups. Interestingly, dw/dw rats exhibited reduced brain edema and less astrocytic infiltration compared with their heterozygous littermates and this effect was reversed by GH-treatment. Because reactive astrocytes are critical for the regulation of poststroke inflammatory processes, maintenance of the blood-brain barrier and neural repair, further studies are warranted to determine the long-term functional consequences of decreased astrocytic activation in GH/IGF-1 deficient animals after cerebral ischemia.

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.

Adipokines and cardiovascular risk in Cushing's syndrome

Cushing's syndrome (CS) is associated with increased cardiovascular morbidity and mortality. Recent evidence also suggests that increased cardiovascular risk may persist even after long-term remission of CS. Increased central obesity, a typical feature of CS, is associated with altered production of adipokines, which contributes to the pathogenesis of several metabolic and cardiovascular complications observed in this condition. In vitro and in vivo studies have shown a relationship between cortisol and adipokines in several experimental settings. In patients with either active or 'cured' CS, an increase in leptin and resistin levels as well as the release of pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-6, may be associated with increased cardiovascular risk. For other adipokines, including adiponectin, results are inconclusive. Studies are needed to further elucidate the interactions between clinical and subclinical increases in cortisol production and altered adipokine release in CS.

Protein C and protein S changes in GH-deficient adults on r-HGH replacement therapy: correlations with PAI-1 and t-PA plasma levels

BACKGROUND

In the rat liver, growth hormone (GH) affects the synthesis of vitamin-K-dependent factors, including Protein C (prot.C) and protein S (prot.S), two natural anticoagulants that prevent hypercoagulable states. Adults with GH deficiency (GHD) are at risk of thrombotic events. High circulating levels of PAI-1 and t-PA, that reflect hypercoagulable states, may contribute to such risk. In GHD adults on replacement therapy with recombinant human GH (r-HGH), %Δ PAI-1 and %Δ t-PA are related to %Δ insulin changes.

OBJECTIVES

To evaluate changes in vitamin-K-dependent factors in GHD on r-HGH replacement.

METHODS

In 60 GHD adults, to relate plasma levels of vitamin-K-dependent factors with those of PAI-1, t-PA and insulin before and after 6-month (6-mo) replacement therapy with r-HGH.

RESULTS

After 6-mo r-HGH replacement, %Δ insulin enhancements occurred in 36/60 subjects. PAI-1, t-PA, Prot.C, Prot.S and FVIIact did not change in them. In the 24/40 subjects that experienced %Δ insulin reductions, Prot.C (p=0.025), Prot.S (p=0.031) and FVIIact (p=0.049) decreased significantly. PAI-1 (p=0.019) and t-PA antigen (p=0.009) behaved similarly. In a multivariate analysis, %∆ PAI-1 (β=0.436, p<0.01) was the strongest predictor of %∆ prot.S, wheras %∆ t-PA (β=0.385, p<0.008) and %∆ insulin (β=0.429, p<0.004) were the strongest predictors of %∆ prot.C. In all cases, regardless of %Δ insulin changes, FII, FVII Ag and FIX levels did not change from baseline.

CONCLUSIONS

In GHD adults on r-HGH replacement, changes in vitamin-K-dependent factors reflect a subtle adaptation of the natural anticoagulant system to PAI-1 and t-PA changes, via the response of insulin to r-HGH.

Blood coagulation and fibrinolysis in patients with acromegaly: increased plasminogen activator inhibitor-1 (PAI-1), decreased tissue factor pathway inhibitor (TFPI), and an inverse correlation between growth hormone and TFPI

OBJECTIVE

Growth hormone/insulin-like growth factor-1(GH/IGF-1) hypersecretion may influence risk factors contributing to the increased cardiovascular morbidity and mortality associated with acromegaly However, so far little is known about the impact of GH/IGF-1 on coagulation and fibrinolysis in acromegalic patients as possible risk factors for cardiovascular disease (CVD). To our knowledge, plasma tissue factor pathway inhibitor (TFPI) and thrombin-activatable fibrinolysis inhibitor (TAFI) levels in these patients have not been investigated. Therefore, the main purpose of this study was to evaluate the markers of endogenous coagulation/fibrinolysis, including TFPI and TAFI, and to investigate the relationships between GH/IGF-1 and these hemostatic parameters and serum lipid profile in patients with acromegaly.

RESEARCH METHODS AND PROCEDURES

A total of 22 patients with active acromegaly and 22 age-matched healthy controls were included in the study. Fibrinogen, factors V, VII, VIII, IX, and X activities, von-Willebrand factor (vWF), antithrombin III (AT III), protein C, protein S, tissue plasminogen activator (t-PA), tissue plasminogen activator inhibitor-I (PAI-1), TFPI and TAFI, as well as common lipid variables, were measured. The relationships between serum GH/IGF-1 and these hemostatic parameters were evaluated.

RESULTS

Compared with the control subjects, fibrinogen, AT III, t-PA, and PAI-1 were increased significantly in patients with acromegaly (P < 0.0001, P < 0.05, P < 0.01, and P < 0.0001, respectively), whereas protein S activity and TFPI levels were decreased significantly (P < 0.05 and P < 0.01, respectively). Plasma TAFI Ag levels did not significantly change in patients with acromegaly compared with the controls. In patients with acromegaly, serum GH levels were inversely correlated with TFPI and apo AI levels (r: -0.514, P: 0.029 and r: -0.602, P: 0.014, respectively). There was also a negative correlation between insulin-like growth factor-1 (IGF-1) and PAI-1 (r: -0.455, P: 0.045).

DISCUSSION

We found some important differences in the hemostatic parameters between the patients with acromegaly and healthy controls. Increased fibrinogen, t-PA, PAI-1 and decreased protein S and TFPI in acromegalic patients may represent a potential hypercoagulable and hypofibrinolytic state, which might augment the risk for atherosclerotic and atherothrombotic complications. Thus, disturbances of the hemostatic system and dyslipidemia may contribute to the excess mortality due to CVD seen in patients with acromegaly.

Increase of classic and nonclassic cardiovascular risk factors in patients with acromegaly

OBJECTIVE

To evaluate the prevalence of classic and nonclassic cardiovascular risk factors in patients with acromegaly.

METHODS

Sixty-two patients with acromegaly (50 with active disease and 12 with controlled acromegaly) and 36 healthy persons (the control group) underwent measurement of lipids, fasting plasma glucose, homeostasis model assessment of insulin resistance (HOMA-IR) index, Lp(a), high-sensitivity C-reactive protein (hsCRP), homocysteine, and variables primarily related to thrombogenesis (fibrinogen, antithrombin III, protein C, and protein S).

RESULTS

In comparison with control subjects, patients with active acromegaly had significantly higher mean values of fasting plasma glucose, total cholesterol, low-density lipoprotein cholesterol, very-low-density lipoprotein (VLDL) cholesterol, triglycerides, Lp(a), HOMA-IR, and fibrinogen as well as lower mean levels of high-density lipoprotein cholesterol and protein S. In both groups, homocysteine, antithrombin III, protein C, and hsCRP levels were similar. Moreover, patients with active acromegaly, in comparison with those who had controlled acromegaly, presented with significantly higher values of fasting plasma glucose, HOMA-IR, triglycerides, VLDL cholesterol, Lp(a), and fibrinogen, whereas hsCRP and protein S were significantly lower. Finally, low levels of high-density lipoprotein cholesterol and protein S as well as elevated values of VLDL cholesterol, triglycerides, HOMA-IR, and fasting plasma glucose were more prevalent in patients with active acromegaly than in the other groups.

CONCLUSION

Our findings demonstrate that, in comparison with control subjects and patients with controlled acromegaly, patients with active acromegaly had a higher frequency of classic and nonclassic cardiovascular risk factors. These findings are potentially very important because acromegaly is associated with a 2- to 3-fold increase in mortality rate, predominantly related to cardiovascular disease.

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.

The coagulation system in endocrine disorders: a narrative review

Endocrine disorders can influence the haemostatic balance. Abnormal coagulation test results have been observed in patients with abnormal hormone levels. Also unprovoked bleeding or thrombotic events have been associated with endocrine disease. The aim of the present review is to summarise the available evidence on the influence of common endocrine disorders on the coagulation system, and their possible clinical implications. We focus on thyroid dysfunction, hyper- and hypocortisolism and growth hormone disturbances, while other endocrine disorders are only briefly discussed. In the published literature a clear bleeding diathesis has only been associated with overt hypothyroidism, mainly mediated by an acquired von Willebrand syndrome. A clinically relevant hypercoagulable state may be present in patients with hyperthyroidism, hypercortisolism or abnormal growth hormone levels, but adequate prospective clinical studies are lacking. Also effects of pheochromocytoma, hyperprolactinaemia and hyperaldosteronism on the coagulation system have been described. It is apparent that unprovoked bleeding and thrombotic episodes can be secondary to endocrine disorders.

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.

Growth hormone, acromegaly, and heart failure: an intricate triangulation

Short-term GH or IGF-I excess provides a model of physiological cardiac growth associated with functional advantage. The physiological nature of cardiac growth is accounted for by the following: (i) the increment in cardiomyocyte size occurs prevalently at expense of the short axis. This is the basis for the concentric pattern of left ventricular (LV) hypertrophy, with consequent fall in LV wall stress and functional improvement; (ii) cardiomyocyte growth is associated with improved contractility and relaxation, and a favourable energetic setting; (iii) the capillary density of the myocardial tissue is not affected; (iv) there is a balanced growth of cardiomyocytes and nonmyocyte elements, which accounts for the lack of interstitial fibrosis; (v) myocardial energetics and mechanics are not perturbed; and (vi) the growth response is not associated with the gene re-programming that characterizes pathologic cardiac hypertrophy and heart failure. Overall, the mechanisms activated by GH or IGF-I appear to be entirely different from those of chronic heart failure. Not to be neglected is also the fact that GH, through its nitric oxide (NO)-releasing action, contributes to the maintenance of normal vascular reactivity and peripheral vascular resistance. This particular kind of interaction of GH with the cardiovascular system accounts for: (i) the lack of cardiac impairment in short-term acromegaly; (ii) the beneficial effects of GH and IGF-I in various models of heart failure; (iii) the protective effect of GH and IGF-I against post-infarction ventricular remodelling; (iv) the reversal of endothelial dysfunction in patients with heart failure treated with GH; and (v) the cardiac abnormalities associated with GH deficiency and their correction after GH therapy. If it is clear that GH and IGF-I exert favourable effects on the heart in the short term, it is equally undeniable that GH excess with time causes pathologic cardiac hypertrophy and, if it is not corrected, eventually leads to cardiac failure. Why then, at one point in time in the natural history of acromegaly, does physiological cardiac growth become maladaptive and translate into heart failure? Before this transition takes places, the acromegalic heart shares very few features with other models of chronic heart failure. None of the mechanisms involved in the progression of heart failure is clearly operative in acromegaly, save for the presence of insulin-resistance and mild alterations of lipoproteins and clot factors. Is this enough to account for the development of heart failure? Probably not. On the other hand, it must be stressed that GH and IGF-I activate several mechanisms that play a protective role against the development of heart failure. These include ventricular unloading, deactivation of neurohormonal components, antiapoptotic effect and enhanced vascular reactivity. Ultimately, all data available concur to hypothesize that acromegalic cardiomyopathy represents a progressive model of cardiac hypertrophy in which the cardiotoxic and pro-remodelling effect is intrinsic to the excessive and unrestrained myocardial growth.