In vitro effect of human recombinant growth hormone on lymphocyte and granulocyte function of healthy and uremic children

Acute Effects of Growth Hormone on the Cellular Immunologic Landscape in Pediatric Patients

INTRODUCTION

Growth hormone (GH) and the immune system have multiple bidirectional interactions. Data about the acute effects of GH on the immune system are lacking. The objective of our study was to evaluate the acute effects of GH on the immune system using time-of-flight mass cytometry.

METHODS

This was a prospective study of pediatric patients who were being evaluated for short stature and underwent a GH stimulation test at a tertiary care center. Blood samples for immunologic markers, i.e., complete blood count (CBC) and time of flight mass cytometry (CyTOF), were collected at baseline (T0) and over the course of three hours (T3) of the test. Differences in immune profiling in patients by timepoint (T0, T3) and GH response (growth hormone sufficient (GHS) versus growth hormone deficient (GHD)) were calculated using a two-way ANOVA test.  Results: A total of 54 patients (39 boys and 15 girls) aged five to 18 years were recruited. Twenty-two participants tested GHD (peak GH <10 ng/ml). The CyTOF analysis showed a significant increase from T0 to T3 in granulocyte percentage, monocyte count, and dendritic cell (DC) count; in contrast, a significant decrease was seen in T lymphocytes (helper and cytotoxic) and IgD+ B lymphocytes. The CBC analysis supported these findings: an increase in total white blood cell count, absolute neutrophil count, and neutrophil percentage; a decrease in absolute lymphocyte count, lymphocyte percentage, absolute eosinophil count, and absolute monocyte count. No significant differences were found between CBC/CyTOF measurements and GH status at either time.

CONCLUSIONS

This study provides the first high-resolution map of acute changes in the immune system with GH stimulation. This implies a key role for GH in immunomodulatory function.

Periodontal disease in adults with untreated congenital growth hormone deficiency: a case-control study

AIM

The aim of this study was to investigate the possible associations between isolated growth hormone deficiency (IGHD) and periodontal attachment loss (PAL) in adults affected by congenital IGHD.

MATERIALS AND METHODS

Forty-five previously identified IGHD subjects were eligible for this study. The final study sample comprised 32 cases (gender:20M/12F; age:44.8 ± 17.5) matched for age, gender, diabetes, smoking status and income to 32 controls (non-IGHD subjects). Participants were submitted to a full-mouth clinical examination of six sites per tooth and were interviewed using a structured, written questionnaire. Periodontitis was defined as proximal PAL≥5 mm affecting ≥30% of teeth.

RESULTS

No significant differences were observed in the percentage of sites with visible plaque between IGHD and non-IGHD subjects (59.4% versus 46.9%, p=0.32). IGHD subjects had significant less supragingival calculus (31.3% versus 59.4%, p=0.02) and more bleeding on probing (71.9% versus 18.8%, p<0.01) than controls. PAL≥5 mm was significantly more prevalent (100% versus 71.9%, p<0.01) and affected more teeth (30.5% versus 6.7%, p<0.01) in cases than in controls. After adjusting for supragingival calculus, IGHD cases had a higher likelihood of having periodontitis than controls (OR=17.4-17.8, 95% CI=2.3-134.9, p=0.004-0.005).

CONCLUSION

Congenital IGHD subjects have a greater chance of having PAL.

Circulating growth hormone binding protein levels and mononuclear cell growth hormone receptor expression in uremia

BACKGROUND

Resistance to growth hormone (GH) in end-stage renal disease (ESRD) causes growth retardation and muscle wasting. In humans, circulating GH binding protein (GHBP), the extracellular domain of the GH receptor that is shed into the circulation and is believed to reflect tissue GH receptor levels, is reduced in uremia and suggests that cellular GH receptor levels are correspondingly reduced. If true, this could be a cause of GH resistance. We set out to establish whether serum GHBP levels reflect cellular GH receptor levels and whether changes in serum GHBP levels are related to nutritional or inflammatory status.

METHODS

GH receptor protein expression in peripheral blood mononuclear cells (PBMC) from 21 ESRD and 14 normal subjects were analyzed by fluorochrome flow cytometry.

RESULTS

The GH receptor density and percent total PBMCs expressing the GH receptor were similar in the 2 groups, and there was no difference in percent GH receptor positive T or B cells or monocytes. In contrast, serum GHBP levels were 80% lower in ESRD. GHBP levels did not correlate with serum albumin, body mass index, or muscle mass but seemed to be partly related to the log serum C-reactive protein levels.

CONCLUSIONS

Serum GHBP levels are markedly reduced in ESRD; this seems to occur independent of nutritional status and may in part be caused by inflammation. Because GH receptor expression on PBMC of ESRD and control subjects was similar, our findings argue against a reduction in GH receptor as a cause of GH resistance and the use of serum GHBP levels as a reliable marker of specific tissue GH receptor levels.

Effect of recombinant human GH on circulating granulocyte colony-stimulating factor and neutrophils in patients with adult GH deficiency

BACKGROUND

We previously reported that short-term continuous subcutaneous infusion (CSI) of recombinant human growth hormone (rhGH) increased plasma erythropoietin levels and hemoglobin concentrations in patients with adult GH deficiency. In the present study, we investigated the effect of rhGH on plasma granulocyte colony-stimulating factor (G-CSF) levels and neutrophil counts in patients with adult GH deficiency.

METHODS

rhGH was administrated for 1 year in six patients with adult GH deficiency (age range, 24-69 years; mean +/- S.E.M., 51.7 +/- 5.8 years; two males and four females) by means of CSI at a rate of 0.25 U/kg per week. Blood samples were obtained in the morning after overnight fasting every month before and after the start of rhGH administration. Plasma GH, insulin-like growth factor I (IGF-I) and G-CSF levels, and neutrophil counts, were measured.

RESULTS

Mean ( +/- S.E.M.) plasma GH levels increased from 0.26 +/- 0.14 to 2.28 +/- 0.20 microg/l 1 month after the start of rhGH administration. An increase of the plasma GH levels was accompanied by an increase in the plasma IGF-I levels from 64.7 +/- 8.5 to 293.3 +/- 80.6 microg/l. Plasma G-CSF levels increased at 2, 3, 8, 9 and 10 months after the start of rhGH administration compared with 28.6 +/- 11.0 ng/l at time 0. The neutrophil counts increased at 2, 3, 7, 8, 9, 11 and 12 months after the start of rhGH administration compared with 2822 +/- 377 neutrophils/microl at time 0.

CONCLUSION

rhGH administration increased plasma G-CSF levels and neutrophil counts. GH and/or IGF-I might stimulate neutrophil production and/or release via G-CSF.