Hypertension-related factors in patients with active and inactive acromegaly

The Heart's Function as a Pump Assessed via Impedance Cardiography and the Autonomic System Balance in Patients with Early-Stage Acromegaly

BACKGROUND

Acromegaly is a rare, chronic disease that involves structural and functional abnormalities of the cardiovascular system. Acromegaly likely affects interactions between the cardiovascular system and the autonomic nervous system (ANS). Therefore, assessing the relationship between sympathetic-parasympathetic balance by analyzing heart rate variability (HRV) and the hemodynamic profile via impedance cardiography (ICG) may be useful in learning the exact nature of interactions between the ANS and the cardiovascular system. The purpose of this study was to assess a possible association between HRV and ICG-based parameters of cardiac function in patients newly diagnosed with acromegaly.

METHODS

This observational cohort study was conducted on 33 patients (18 men, mean age of 47 years) newly diagnosed with acromegaly and no significant comorbidities. A correlation analysis (Spearman's rank coefficient R) of the parameters assessed via ICG and the HRV assessed via 24 h ambulatory electrocardiography was performed. ICG assessments included the following parameters: stroke volume index (SI), cardiac index (CI), acceleration index (ACI), velocity index (VI), and Heather index (HI). The analysis of HRV included both time-domain parameters (pNN50, SDNN, SDSD, rMSSD) and frequency-domain parameters (total power (TP) and its individual frequency bands: low-frequency (LF day/night), high-frequency (HF day/night), and the LF/HF ratio (day/night)).

RESULTS

Frequency-domain HRV analysis showed the following correlations: (1) lower nighttime LF values with higher ACI (R = -0.38; p = 0.027) and HI (R = -0.46; p = 0.007) values; (2) higher nighttime HF values with higher ACI (R = 0.39; p = 0.027) and HI (R = 0.43; p = 0.014) values; (3) lower nighttime LF/HF values with higher ACI (R = -0.36; p = 0.037) and HI (R = -0.42; p = 0.014) values; (4) higher nighttime TP values with higher SI values (R = 0.35; p = 0.049). Time-domain parameters of HRV showed a significant correlation only between the nighttime values of SDSD and SI (R = 0.35; p = 0.049) and between the daytime and nighttime values of SDNN and HR (R = -0.50; p = 0.003 and R = -0.35; p = 0.046). In multivariate regression, only ACI was revealed to be independently related to HRV.

CONCLUSIONS

In patients newly diagnosed with acromegaly, the relationship between the sympathetic-parasympathetic balance assessed via HRV and the hemodynamic profile assessed via ICG was revealed. Better function of the left ventricle was associated with a parasympathetic shift in the autonomic balance.

Post-treatment heterogeneity of cardiometabolic risk in patients with acromegaly: The impact of GH and IGF-1

BACKGROUND

Metabolic abnormalities are frequently seen in patients with acromegaly. However, it is not clear to what extent growth hormone/insulin-like growth factor-1 (GH/IGF-1) contributes to the development of these abnormalities.

OBJECTIVE

This study aimed to explore the impact of postoperative GH/IGF-1 on different aspects of metabolic abnormalities in patients with acromegaly.

METHODS

This retrospective, registry-based study conducted on 102 patients with acromegaly. The impact of GH/IGF-1 on the cardiometabolic risk factors at 3-12 months after surgery has been investigated using linear and logistic regression models.

RESULTS

In this study, each 1 ng/ml increase in the level of GH was significantly associated with a 2 mg/dl increase in the level of fasting blood glucose (FBG), a 0.5 mmHg increase in the level of systolic blood pressure (SBP), and a 0.9 mmHg increase in the level of diastolic blood pressure (DBP). Upon multivariate analysis, GH, but not IGF-1, significantly increased the odds of diabetes mellitus (DM) (OR; 1.2, 95% CI; 1.0-1.4, p = .025).

CONCLUSIONS

Our findings indicated at early postoperative stage, GH is significantly associated with the levels of FBG, SBP, and DBP. Moreover, GH, but not IGF-1, appears as a predictive factor for the presence of DM. However, neither GH nor IGF-1 could predict the presence of hypertension HTN, or dyslipidemia in this study.

ABBREVIATIONS

CVD: Cardiovascular disease; GH: Growth hormone; IGF-1: Insulin-like growth factor 1; BMI: Body mass index; HTN: hypertension; IPTR: Iran Pituitary Tumor Registry; WC: Waist circumference; MRI: Magnetic resonance imaging; FBG: Fasting blood glucose; HbA1C: Glycated hemoglobin; TG: Triglyceride; LDL: Low density lipoprotein; HDL: High density lipoprotein; SBP: Systolic blood pressure; DBP: Diastolic blood pressure.

GH and IGF-I levels and tumor shrinkage in response to first generation somatostatin receptor ligands in acromegaly: a comparative study between two reference centers for pituitary diseases in Brazil

PURPOSE

To compare biochemical and tumor response rates between two reference centers for pituitary diseases in Brazil after primary and adjuvant therapy with somatostatin receptor ligands (SRL) in acromegaly.

METHODS

Patients were classified as non-responders (NR), partial responders (PR), and full responders (FR) to 12-month SRL therapy according to: [criteria A] normal IGF-I and random GH (rGH) < 1 ng/mL (FR); ≥ 50% decrease of IGF-I and/or rGH (PR); < 50% decrease of IGF-I and rGH (NR); [criteria B] normal IGF-I (FR); ≥ 50% decrease of IGF-I (PR); < 50% decrease of IGF-I (NR). Tumor shrinkage <20% defined poor responders (tPR) and ≥ 20% good responders (tGR).

RESULTS

We studied 219 acromegaly patients (59% women, age 43.1 ± 13.9 years; 73 from Center I and 146 from Center II). After SRL therapy, the proportion of FR, PR, and NR by criteria A and B was 30.2 vs 49.1%, 52.8 vs 21.2% and 17 vs 29.7%, respectively (p < 0.001). Considering criteria A or B separately, there was no difference in the proportion of FR, PR and NR between two centers. However, when comparing criteria A and B, the Center I showed a difference of 30.9% in classification of FR in relation to 13.2% observed in Center II (p = 0.006). tGR were 51.4% of patients, with no differences between the centers.

CONCLUSIONS

IGF-I alone significantly increased positive response rates to SRLs, whereas the inclusion of rGH levels into therapeutic decision might lead to a significant increment on the costs of acromegaly management.

Association between insulin-like growth factor-1 and systolic blood pressure in children and adolescents with short stature

The relationship between insulin‐like growth factor‐1 (IGF‐1) and systolic blood pressure (SBP) is controversial in adults and children. The purpose of this study was to investigate the relationship between the IGF‐1 standard deviation score (IGF‐1 SDS) and SBP in children with short stature. A cross‐sectional analysis including 1315 children with short stature was conducted from March 2013 to October 2020. We estimated IGF‐1, blood pressure and other laboratory tests, and anthropometric indicators were also evaluated. Subgroup analyses of the pubertal stage, sex, growth hormone levels, thyroid hormone levels, fasting blood glucose levels, and triglyceride levels were performed. A positive association between the IGF‐1 SDS and SBP was observed by univariate analysis (p < .001). We further found a nonlinear association between the IGF‐1 SDS and SBP. The inflection point for the curve was found at an IGF‐1 SDS level of −2.91. In multivariate piecewise linear regression, there was a positive association between the IGF‐1 SDS and SBP when the IGF‐1 SDS was greater than −2.91 (β 1.56, 95% CI: 0.91, 2.22; p < .001). However, we did not observe a significant relationship between the IGF‐1 SDS and SBP when the IGF‐1 SDS level was less than −2.91 (β −0.95, 95% CI −3.17, 1.28; p = .379). This association was consistent across subgroup analyses. The present study demonstrated that there is a nonlinear relationship between the IGF‐1 SDS and SBP in children with short stature. Increased serum IGF‐1 levels were associated with elevated SBP when the IGF‐1 levels reached the inflection point.

Pretreatment serum GH levels and cardio-metabolic comorbidities in acromegaly; analysis of data from Iran Pituitary Tumor Registry

Background

Acromegaly is a rare chronic disabling disorder, in which growth hormone (GH) excess is associated with a range of clinical features and systemic complications. The present study aims to evaluate the association between pretreatment basal GH levels as well as GH levels after oral glucose tolerance test (OGTT) and cardio-metabolic comorbidities, including diabetes mellitus (DM), left ventricular hypertrophy (LVH) and hypertension (HTN) in patients with active acromegaly.

Methods

A retrospective study of the medical records regarding 113 patients with acromegaly registered at two main centers of Iran Pituitary Tumor Registry during 2011-2018.

Results

The mean age of the patients was 42.76 ± 11.6 (range: 21-72) years. Mean GH level at baseline was 21 ng/ml while nadir GH levels at 60 and 120 min after glucose were 6.95 and 9.05 ng/ml, respectively. There was a negative correlation between age and basal serum GH level (r= -0.196, p = 0.038). Hypertension and diabetes mellitus were detected in 26.8% and 19.7% of the patients. A positive correlation was detected between serum GH values and systolic blood pressure. There was not any significant difference in basal GH and GH post OGTT regarding DM, Diastolic blood pressure and LVH.

Conclusions

Our findings suggest that pretreatment basal GH levels are higher in younger patients with acromegaly. Furthermore, higher GH values (0, 60 and 120 min) during OGTT are associated with higher systolic blood pressure. A comprehensive evaluation of this population regarding comorbidities should be performed.

Changes in metabolic parameters and cardiovascular risk factors after therapeutic control of acromegaly vary with the treatment modality. Data from the Bicêtre cohort, and review of the literature

CONTEXT

Untreated acromegaly is associated with increased morbidity and mortality due to malignant, cardiovascular, and cerebrovascular disorders. Effective treatment of acromegaly reduces excess mortality, but its impact on cardiovascular risk factors and metabolic parameters are poorly documented.

AIM

We analyzed changes in cardiovascular risk factors and metabolic parameters in patients receiving various treatment modalities.

PATIENTS AND METHODS

We retrospectively studied 96 patients with acromegaly, both at diagnosis and after IGF-I normalization following surgery alone (n = 51) or medical therapy with first generation somatostatin analogues (SSA, n = 23), or pegvisomant (n = 22). Duration of follow-up was 77 (42-161) months, 75 (42-112) months, and 62 (31-93) months, in patients treated with surgery alone, SSA, and pegvisomant, respectively. In all the cases except four, patients treated medically had underwent previous unsuccessful surgery.

RESULTS

IGF-I normalization was associated with increased body weight, decreased systolic blood pressure (SBP) in hypertensive patients, decreased fasting plasma glucose (FPG) and HOMA-IR and HOMA-B levels, increased HDL cholesterol (HDLc); whereas, LDL cholesterol (LDLc) was not significantly different. Plasma PCSK9 levels were unchanged in patients with available values. Cardiovascular and metabolic changes varied with the treatment modality: surgery, but not pegvisomant, had a beneficial effect on SBP; FPG decreased after surgery but increased after SSA; the decline in HOMA-IR was only significant after surgery; pegvisomant significantly increased LDLc and total cholesterol; whereas SA increased HDLc and had no effect on LDLc levels.

CONCLUSION

Treatments used to normalize IGF-I levels in patients with acromegaly could have differential effects on cardiovascular risk factors and metabolic parameters.

Smooth Muscle-Specific BCL6+/- Knockout Abrogates Sex Bias in Chronic Hypoxia-Induced Pulmonary Arterial Hypertension in Mice

The "estrogen paradox" in pulmonary arterial hypertension (PAH) refers to observations that while there is a higher incidence of idiopathic PAH in women, rodent models of PAH show male dominance and estrogens are protective. To explain these differences, we previously proposed the neuroendocrine-STAT5-BCL6 hypothesis anchored in the sex-biased and species-specific patterns of growth hormone (GH) secretion by the pituitary, the targeting of the hypothalamus by estrogens to feminize GH secretion patterns, and the role of the transcription factors STAT5a/b and BCL6 as downstream mediators of this patterned GH-driven sex bias. As a test of this hypothesis, we previously reported that vascular smooth muscle cell- (SMC-) specific deletion of the STAT5a/b locus abrogated the male-dominant sex bias in the chronic hypoxia model of PAH in mice. In the present study, we confirmed reduced BCL6 expression in pulmonary arterial (PA) segments in both male and female SMC:STAT5a/b-/- mice. In order to test the proposed contribution of BCL6 to sex bias in PAH, we developed mice with SMC-specific deletion of BCL6+/- by crossing SM22α-Cre mice with BCL6-floxed mice and investigated sex bias in these mutant mice in the chronic hypoxia model of PAH. We observed that the male-bias observed in wild-type- (wt-) SM22α-Cre-positive mice was abrogated in the SMC:BCL6+/- knockouts-both males and females showed equivalent enhancement of indices of PAH. The new data confirm BCL6 as a contributor to the sex-bias phenotype observed in hypoxic PAH in mice and support the neuroendocrine-STAT5-BCL6 hypothesis of sex bias in this experimental model of vascular disease.

Has acromegaly been diagnosed earlier?

PURPOSE

We investigated whether acromegaly has been diagnosed earlier at the Niigata Medical and Dental University Hospital.

METHODS

Patients with acromegaly (n = 81) who underwent their first transsphenoidal surgery from 2006 to 2015 were reviewed. Two groups were compared: those who underwent surgery between 2006 and 2010 (n = 35) and those who underwent surgery between 2011 and 2015 (n = 46). We compared clinical features and serum levels of the growth hormone (GH) and insulin-like growth factor-1 (IGF-1), hypertension (HT) and diabetes mellitus (DM) prevalence between the two groups.

RESULTS

Compared with the early group, microadenomas (<10 mm) were more prevalent in the late group (0% vs. 15.2%, p < .05). Serum IGF-1 standard deviation score (SDS) was significantly lower in the late group (8.57 ± 2.50 vs. 6.44 ± 2.30, p < .001). In both groups, mean IGF-1 SDS was significantly lower in patients without DM than in those with DM (6.9 ± 2.6 vs. 8.3 ± 2.4, p = .02). Logistic regression analysis showed that serum GH and IGF-1 levels were significantly higher in patients with DM than in those without DM.

CONCLUSION

Regarding operated cases of GH-producing pituitary adenoma, acromegaly clinical manifestations tended to be milder at diagnosis in later years of the decade, and acromegaly was diagnosed at lower IGF-1 levels and in smaller lesions. Further study is mandatory for the generalization of this trend.

The ongoing challenge of discrepant growth hormone and insulin-like growth factor I results in the evaluation of treated acromegalic patients: a systematic review and meta-analysis

OBJECTIVE

Growth hormone (GH) and insulin-like growth factor I (IGF-I) are the principal biomarkers used to assess disease activity in acromegaly, and any discrepancy between them renders interpretation of results inconclusive. Purpose of this study was to assess the frequency of this discrepancy and identify parameters that might affect its occurrence.

DESIGN

A systematic review of MEDLINE and Scopus was performed (1987-2013) followed by a meta-analysis to address the frequency of discrepant results between GH and IGF-I levels. Meta-regression and subgroup analyses were performed assessing the effects of the year of publication, the different types of GH testing and GH assays used, as well as the impact of treatment with somatostatin analogues (SSAs) on the occurrence of this discrepancy.

RESULTS

The analysis retrieved 39 eligible studies totalling 7071 patients. The pooled discordance rate between GH and IGF-I was 25·7% (95% CI: 22·3-29·4), and the predominant format was that of elevated IGF-I with normal GH levels (15·3%, 95% CI: 12·5-18·7). No significant correlation between the discordance rate and the year of publication was shown; whereas, the use of ultrasensitive GH assays resulted in higher discordance rates (30·7%, 95% CI: 25·9-35·9 vs 19·8%, 95% CI: 14·1-27·2, P = 0·04) as did treatment with SSAs (32·5%, 95% CI: 27·8-37·4) vs (21·6%, 95% CI: 17·8-25·6, P = 0·001).

CONCLUSIONS

Discrepancy between GH and IGF-I results is encountered in a quarter of treated patients with acromegaly, especially when using ultrasensitive GH assays or in patients receiving SSAs, a fact that the clinician should take into consideration when making clinical decisions.

[Etiology of endocrine arterial hypertensions: about a series of cases]

Arterial hypertensions (HTA) of endocrine origin are a rare cause of hypertension; HTA overall prevalence don't exceed 4% of hypertensive patients. Research interest in endocrine HTA is due to the severity of some life-threatening, potentially curable and reversible forms of HTA. The aim of our study was to determine the clinical, paraclinical, etiological and therapeutic profile of secondary HTA of endocrine origin in patients treated in endocrinology department at the University Hospital Mohamed VI in Marrakech. We conducted a prospective, descriptive study spanned 4 years, enrolling 45 patients with endocrine HTA. The average age was 44.89 years, with a clear predominance of women (sex ratio 0.49). Etiology of endocrine HTA was dominated by pheochromocytoma (17 cases), hypercorticism (11 cases) and acromegaly (8 cases). HTA were paroxysmal in 24.4%. HTA were immediately classified as grade 3 severe in 40% of cases. HTA were complicated by heart disease in 24% of cases and by renal disease in 20% of cases. Curative treatment cleared up HTA in 60% of cases (27 cases). The diagnosis of secondary endocrine HTA is sometimes difficult because of the lack of clinical specificity. It is not unusual for HTA to be the only manifestation of the disease. In our study we noted the paroxysmal and severe nature of HTA. The potentially curable nature of HTA in more than two thirds of cases, demostrates the importance of early diagnosis of each severe HTA resistant to treatment or in the presence of suggestive clinical, biological or radiological signs.

Assessment of cardiac autonomic functions by heart rate recovery, heart rate variability and QT dynamicity parameters in patients with acromegaly

Cardiovascular complications are the most common causes of morbidity and mortality in acromegaly. However, there is little data regarding cardiac autonomic functions in these patients. Herein, we aimed to investigate several parameters of cardiac autonomic functions in patients with acromegaly compared to healthy subjects. We enrolled 20 newly diagnosed acromegalic patients (55% female, age:45.7 ± 12.6 years) and 32 age- and gender-matched healthy subjects. All participants underwent 24 h Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting 1st, 2nd and 3rd minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV) and QT dynamicity analysis. Baseline characteristics were similar except diabetes mellitus and hypertension among groups. Mean HRR1 (29.2 ± 12.3 vs 42.6 ± 6.5, p = 0.001), HRR2 (43.5 ± 15.6 vs 61.1 ± 10.8, p = 0.001) and HRR3 (46.4 ± 16.2 vs 65.8 ± 9.8, p = 0.001) values were significantly higher in control group. HRV parameters as, SDNN [standard deviation of all NN intervals] (p = 0.001), SDANN [SD of the 5 min mean RR intervals] (p = 0.001), RMSSD [root square of successive differences in RR interval] (p = 0.001), PNN50 [proportion of differences in successive NN intervals >50 ms] (p = 0.001) and high-frequency [HF] (p = 0.001) were significantly decreased in patients with acromegaly; but low frequency [LF] (p = 0.046) and LF/HF (p = 0.001) were significantly higher in acromegaly patients. QTec (p = 0.009), QTac/RR slope (p = 0.017) and QTec/RR slope (p = 0.01) were significantly higher in patients with acromegaly. Additionally, there were significant negative correlation of disease duration with HRR2, HRR3, SDNN, PNN50, RMSSD, variability index. Our study results suggest that cardiac autonomic functions are impaired in patients with acromegaly. Further large scale studies are needed to exhibit the prognostic significance of impaired autonomic functions in patients with acromegaly.

Revisiting the relationship between blood pressure and insulin-like growth factor-1

Conflicting evidence exists on the relationship between blood pressure (BP) and insulin-like growth factor-1 (IGF-1). We reviewed available articles and pooled extrapolated regression coefficients for the association between BP and total IGF-1 as reported in the literature and included additional data from 912 individuals from the general population. We identified 20 studies including 11 704 subjects. We also measured total IGF-1, insulin-like binding protein-3, and BP in 912 black and white men and women from South Africa (aged 20-70 years). When plotting positive and negative weighed regression coefficients (29 data points) against IGF-1, we found a significant positive relationship (r=0.31; P<0.001; n=11 704) intercepting the 0 point at 191 ng/mL IGF-1, suggesting an inverse BP/IGF-1 relationship in low IGF-1 conditions, and a positive relationship in overtly high IGF-1 conditions. In conclusion, our findings suggest that the relationship between BP and IGF-1 is dependent on, or related to, IGF-1 concentrations, as an expression of direct or reverse causality. Low IGF-1 bioavailability (associated with aging and vascular deterioration), resistance to IGF-1, and the complex interplay between IGF-1 and other vasoactive hormones could mask the vasoprotective functions of IGF-1 in cross-sectional studies or could modify their functions in prospective studies.

Pulmonary function testing and chest tomography in patients with acromegaly

Background

Despite the gradual improvement in treatment procedures and cure rates of acromegaly, a steady increase in the mortality rate due to respiratory disease has been documented in recent decades. In this study, our objectives were to describe the abnormalities in lung structure and function that occur in acromegalic patients and to correlate these changes with hormonal levels.

Methods

This cross-sectional study included 20 acromegalic patients and 20 age-and height-matched control subjects, all non-smokers. All subjects underwent spirometry, whole body plethysmography, carbon monoxide diffusing capacity, and respiratory muscle strength. Acromegalic patients also performed high-resolution computed tomography (HRCT).

Results

Most patients were female (65%), with a mean age of 52.5 ± 13 years. Acromegalic patients showed lower values of maximum expiratory pressure (55.9 ± 17.1 vs. 103.7 ± 19.2%; p < 0.001) and maximum inspiratory pressure (71.4 ± 27.8 vs. 85.3 ± 24.1%; p = 0.005) compared to control subjects. The values of forced vital capacity (107.1 ± 15.9 vs. 98.9 ± 21.4%; p = 0.028), total lung capacity – TLC (107.3 ± 12.9 vs. 93.7 ± 7.60%; p = 0.002), residual volume (114.1 ± 22.7 vs. 90.0 ± 14.6%; p < 0.001), and airways’ resistance (3.82 vs. 2.31 cmH₂O/L/s; p = 0.039) were greater in acromegalic patients than in control subjects. The difference between the TLC measured by plethysmography and the V_A (alveolar volume) measured during the DL_CO maneuver was higher in acromegalic patients than in control subjects (0.69 ± 0.46 vs. 0.19 ± 0.61 L; p = 0.021). The main findings in HRCT in acromegalic patients were air trapping, airway calcification and bronchiectasis, which were observed in 60%, 40% and 35% of cases, respectively. There was no significant correlation between the levels of growth hormone and insulin-like growth factor I, the lung function and the air trapping.

Conclusions

Acromegalic patients show changes consistent with the involvement of the small airways and ventilation inhomogeneity, both in terms of lung function and structure. However, air trapping cannot be explained either by hormone levels or changes in lung function.