Extracellular water and blood pressure in adults with growth hormone (GH) deficiency: a genotype-phenotype association study

Individual sensitivity to growth hormone replacement in adults

The metabolic actions of growth hormone (GH) last a lifetime and involve several physiological functions associated with the control of body composition, energy metabolism, water regulation, immune response, cardiovascular performance, physical and mental work. Adult patients with GH deficiency (GHD) present a constellation of clinical findings, which include increased total and visceral body fat, low bone and muscle mass, reduced muscle strength, impaired anaerobic physical capacity, unfavorable cardiovascular profile, and poor quality of life. Recombinant human GH (rhGH) therapy has been proved to reverse or improve many abnormalities associated with GHD in adult life, but the therapeutic response is highly variable among patients and influenced by multiple factors, which are the main focus of this narrative review. Given the individual sensitivity of adult GHD patients to rhGH replacement, dose regimens evolved from weight-based to individualized dose-titration strategies, which improved efficacy and reduced the frequency of adverse events. Individual tailoring and maintenance doses of rhGH are mainly influenced by age, age at GHD onset, sex, body mass index, baseline GH status, quality of life and other pituitary hormone replacements. In addition, genetic background and poor adherence due to patient or product-related factors might play a role in the responsiveness to rhGH therapy. There have been attempts to develop predictive mathematical models to distinguish good and poor responders to rhGH therapy, but thus far none of them have been prospectively tested and validated in a large cohort of adult GHD individuals.

Natriuretic Effect of Two Weeks of Dapagliflozin Treatment in Patients With Type 2 Diabetes and Preserved Kidney Function During Standardized Sodium Intake: Results of the DAPASALT Trial

OBJECTIVE

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk for heart failure hospitalization potentially by inducing sodium excretion, osmotic diuresis, and plasma volume contraction. Few studies have investigated this hypothesis, but none have assessed cumulative sodium excretion with SGLT2 inhibition during standardized sodium intake in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The DAPASALT trial was a mechanistic, nonrandomized, open-label study in patients with type 2 diabetes with preserved kidney function on a controlled standardized sodium diet (150 mmol/day). It evaluated the effects of dapagliflozin on sodium excretion, 24-h blood pressure, and extracellular, intracellular, and plasma volumes at the start of treatment (ST) (days 2-4), end of treatment (ET) (days 12-14), and follow-up (FU) (days 15-18).

RESULTS

Fourteen patients were included in the efficacy analysis. Mean (SD) baseline sodium excretion (150 [32] mmol/24-h) did not significantly change during treatment (change at ST: -7.0 mmol/24-h [95% CI -22.4, 8.4]; change at ET: 2.1 mmol/24-h [-28.8, 33.0]). Mean baseline 24-h systolic blood pressure was 128 (10) mmHg and significantly reduced at ST (-6.1 mmHg [-9.1, -3.1]; P < 0.001) and ET (-7.2 mmHg [-10.0, -4.3]; P < 0.001). Dapagliflozin did not significantly alter plasma volume or intracellular volume, while extracellular volume changed at ST (-0.7 L [-1.3, -0.1]; P = 0.02). As expected, 24-h urinary glucose excretion significantly increased during dapagliflozin treatment and reversed during FU.

CONCLUSIONS

During standardized sodium intake, dapagliflozin reduced blood pressure without clear changes in urinary sodium excretion, suggesting that factors other than natriuresis and volume changes may contribute to the blood pressure-lowering effects.

Cardiovascular effects of growth hormone (GH) treatment on GH-deficient adults: a meta-analysis update

BACKGROUND

It is still unclear whether growth hormone (GH) replacement is able to improve cardiovascular parameters in adults with GH deficiency (AGHD) from the updated clinical trials reported to date.

METHODS AND RESULTS

We systematically reviewed clinical trials of GH treatment on AGHD patients in recent decade, and evaluated the effects of GH on cardiovascular parameters assessed by echocardiography. 11 clinical trials were identified in 3 bibliographic databases. We conducted a combined analysis of effects on four aspects: General indicators: baseline heart rate (BHR), peak heart rate (PHR), systolic blood pressure (SBP), diastolic blood pressure (DBP); Cardiac structure: left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), left ventricular interventricular septum (LVIS), left ventricular mass (LVM), left ventricular posterior wall (LVPW); Cardiovascular function: deceleration time of E wave (DT), E/A ratio (E/A), ejection fraction (EF), NT-BNP; Life quality: peak VO₂, VE/VCO₂ slope. Overall effect size was used to evaluate significance, and weighted mean difference after GH treatment was given to appreciate size of the effect. GH treatment was associated with a significant increase in BHR (3.03[2.00, 4.06]), LVIS (0.50[0.43, 0.57]), LVPW (0.50[0.43, 0.57]), and EF (2.12[1.34, 2.90]). Overall effect sizes were negative significant for DBP (- 1.19[- 2.33, - 0.05]), LVEDV (- 9.84[- 16.53, - 3.15]), NT-BNP (- 206.34[- 308.95, - 103.72]), and VE/VCO2 slope (- 2.31[- 2.92, - 1.71]).

CONCLUSIONS

As assessed by echocardiography, GH administration may improve the general vital signs and life quality of AGHD patients, based on the positive effect on BHR and negative effects on DBP and VE/VCO₂ slope. Also, GH treatment would influence the structure of heart with positive effects on LVIS, LVPW and negative effect on LVEDV, which together with the increase of EF and decrease of NT-BNP, then resulting in improving the systolic function of AGHD patients.

Personalized approach to growth hormone replacement in adults

Growth hormone (GH) deficiency (GHD) in adults is well-characterized and includes abnormal body composition, reduced bone mass, an adverse cardiovascular risk profile, and impaired quality of life. In the early 1990s, it was also shown that patients with hypopituitarism without GH replacement therapy (GHRT) had excess mortality. Today, GHRT has been shown to decrease or reverse the negative effects of GHD. In addition, recent papers have shown that mortality and morbidity are approaching normal in hypopituitary patients with GHD who receive modern endocrine therapy including GHRT. Since the first dose-finding studies, it has been clear that efficacy and side effects differ substantially between patients. Many factors have been suggested as affecting responsiveness, such as sex, age, age at GHD onset, adherence, and GH receptor polymorphisms, with sex and sex steroid replacement having the greatest impact. Therefore, the individual tailoring of GH dose is of great importance to achieve sufficient efficacy without side effects. One group that stands out is women receiving oral estrogen replacement, who needs the highest dose. Serum insulin-like growth factor-1 (IGF-1) is still the most used biochemical biomarker for GH dose titration, although the best serum IGF-1 target is still debated. Patients with GHD due to acromegaly, Cushing's disease, or craniopharyngioma experience similar effects from GHRT as others. Arch Endocrinol Metab. 2019;63(6):592-600.

Update on GH therapy in adults

Over the last three decades, short- and long-term observational studies, clinical trials, systematic reviews, and meta-analyses have provided relevant information on the efficacy and safety of growth hormone (GH) replacement therapy in adults with GH deficiency (AGHD). The knowledge acquired during this time has been compiled into different guidelines that offer clinicians an evidence-based, practical approach for the management of AGHD. There are, however, still open questions in some key areas in which recommendations are supported by only moderate or weak evidence. In the last recent years, the development of long-acting GH preparations has created new therapeutic possibilities by decreasing injection frequency, improving adherence and thereby potentially maximizing clinical outcomes. The aims of this review are to advance our understanding on the diagnosis and treatment of AGHD and to present an update and future perspectives on the use of long-acting GH preparations.