Retinal Neural and Vascular Structure in Isolated Growth Hormone Deficiency Children and Evaluation of Growth Hormone Treatment Effect

Quantitative measures of the vascular and neural components of the retina in adult individuals with congenital and untreated growth hormone deficiency

Background

The somatotrophic axis, including hypothalamic growth hormone (GH)-releasing hormone (GHRH), pituitary GH and circulating IGF-I, is critical for body size. However, the local production of GH/IGF-I (and IGF-II) and other peptides is relevant for other body functions, such as vascular, brain, and retinal function. The consequences of GH deficiency (GHD) on the retinal structure are still unclear, possibly reflecting the heterogeneity of patients and the different types of assessment in previous publications. Our purpose was to assess quantitative measures of the vascular and neural components of the retina in subjects with severe congenital isolated GHD (IGHD).

Methods

A cross-sectional study was carried out in 25 adult IGHD subjects and 25 age- and gender-matched controls. Interview, physical examination, laboratory data, optical coherence tomography (OCT) and OCT angiography (OCTA) were performed.

Results

OCT revealed no difference in the areas of the nerve fiber layer average, nor in the areas of superior, inferior, or nasal quadrants, between the two groups. However, areas of the temporal quadrant (p = 0.041), the optical disc (p = 0.042), the cup (p < 0.0001), as well as the cup/disc ratio (p < 0.0001), were higher in IGHD subjects than controls. The rim area was smaller (p = 0.002), although still normal. In OCTA, there was no difference in the minimum foveal thickness, central fovea, foveal avascular zone, and retinal density in any assessed area.

Conclusions

In conclusion, congenital IGHD does not affect quantitative measures of the vascular and neural retina, and it is associated with increased optical disc in this genetically homogeneous cohort.

Assessment of the retinal vasculature in healthy Chinese preschool children aged 4-6 years old using optical coherence tomography angiography

PURPOSE

To establish normal parameters of macular and optic disc vasculature by optical coherence tomography angiography (OCTA) in healthy preschool children aged 4-6 years old in China. OCTA reflects retinal metabolism and development in children at these ages and could be used clinically and in future studies to aid diagnosis and prediction of retinal abnormalities and developmental stagnation.

METHODS

In this cross-sectional study, we measured foveal, parafoveal, and perifoveal vessel density in the superficial capillary plexus (SCP); the deep capillary plexus (DCP), the foveal avascular zone (FAZ), and the radial capillary peripapillary (RPC) in the optic disc using investigational spectral-domain OCTA. The magnification effect of the FAZ area and microvasculature measurements was corrected by Littman and the modified Bennett formula.

RESULTS

A total of 242 eyes (116 males and 126 females, 5.31 ± 0.73 years) were recruited for the analysis. The mean macular vessel density was 48.10 ± 2.92% and 48.74 ± 6.51% in the SCP and the DCP, respectively. The RPC vessel density was 47.17 ± 2.52%, 47.99 ± 4.48%, and 48.41 ± 3.07% in the whole image, inside disc, and peripapillary, respectively; and the mean FAZ area was 0.28 ± 0.11 mm². A significant difference between male and female participants was found in the retinal vasculature (DCP, SCP, and RPC). None of these parameters were significantly different in age (P > 0.05), except that DCP slightly increased with aging. The right and left eyes had good consistency in the parameters of the macula and optic disc.

CONCLUSIONS

Our study establishes the macular and optic disc OCTA reference values in 4- to 6-year-old healthy preschool children. They may be used in longitudinal OCTA studies and clinical applications.

Topographic and specular microscopic evaluation of cornea and meibomian gland morphology in children with isolated growth hormone deficiency

PURPOSE

To evaluate whether the anterior segment topographic measurements, meibomian gland (MG), and non-invasive tear film break-up time (NITFBUT) differ between healthy children and children with isolated growth hormone deficiency (GHD).

METHODS

A total of 74 eyes of 37 children with GHD and 84 eyes of 42 age- and sex-matched healthy children were included in the study. The spherical equivalence (SE), mean keratometry (Km), corneal thickness, corneal volume (CV), anterior chamber depth (ACD), topographic NITFBUT, qualitative and quantitative MG measurements, corneal endothelial cell density (CD), and proportion of hexagonal cells (HG) were analysed.

RESULTS

The mean SE level of GHD group was similar between groups (p = 0.017). Back Km values were insignificantly steep in children with GHD (p = 0.004, with Bonferroni correction). Specular microscopy analysis was not different between groups. MG loss of GHD group were higher than control group (p < 0.001). The MG morphology analysis and distortion grade were not different between groups (p > 0.05).

CONCLUSIONS

Our results showed that the growth hormone (GH) may have an important role on the anterior segment parameters; however, it is not clear that this misregulation leads to a clinical scenario in childhood. Future studies investigating GHD and/or GH therapy on the ocular surface system are required to clearly demonstrate basic mechanism of GH action.

An improved method of culturing somatotropic cells from rat adenohypophysis

This study aimed to propose a simple and practical method for culturing primary rat somatotropic cells in vitro free of pericytes contamination. Rat adenohypophyses were randomly divided into two groups. An improved method was used in group A (digesting adenohypophysis with 0.25% trypsin-EDTA, followed by removing pericytes by double filtration and using serum-free medium for culturing somatotropic cells). The traditional method was used in group B (digesting adenohypophysis with 0.35% collagenase, using serum medium for culturing somatotropic cells, and removing pericytes by changing the culture dish). The numbers and viability of somatotropic cells were higher in group A than in group B after 6 days. GH secretion of somatotropic cells was also higher in group A than in group B. Besides, the pericytes grew rapidly only in group B after 3 days. α-SMA, type I collagen, and type III collagen had weaker expression in group A. Also, the viability of pericytes decreased in group A. The improved method could solve the problem of pericytes contamination, and the culture of primary rat somatotropic cells in vitro was successful. This method can be used for other primary cultures with pericytes contamination.