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Growth hormone suppression and nonproliferative diabetic retinopathy: a preliminary feasibility study
S L Shumak1, L D Grossman, E Chew
1Department of Medicine, Toronto General Hospital, Ontario.
Abstract:
We used the long acting somatostatin analogue SMS 201-995 in order to examine the feasibility and effect of medical suppression of growth hormone in nonproliferative diabetic retinopathy. Six insulin-dependent diabetic subjects with nonproliferative retinopathy were studied. After eight weeks of SMS 201-995 administration, 24-hour integrated plasma growth hormone concentrations had declined by 47.0 +/- 9.3% of pretreatment values (p less than 0.01), and insulin requirements fell from 40.7 +/- 6.7 units per day to 32.2 +/- 6.9 units per day (p less than 0.01). Plasma levels of somatomedin-C were low before SMS 201-995 (0.5 +/- 0.1 U/ml) and remained unchanged at eight weeks (0.6 +/- 0.1 U/ml; p = ns). During SMS 201-995 administration, best corrected visual acuity improved in both right eyes (53.8 +/- 2.57 to 59.8 +/- 0.7 letters, p less than 0.05) and left eyes (54.8 +/- 2.8 to 61.7 +/- 1.23 letters, p less than 0.03). Fluorescein angiography and stereo fundus photography demonstrated concurrent improvement in retinopathy level in only two subjects. Following cessation of SMS 201-995 treatment, visual acuity returned to pretreatment levels in both right eyes (54.5 +/- 2.4 letters, p = ns compared to baseline) and left eyes (55.8 +/- 2.6 letters, p = ns compared to baseline). These results demonstrate that growth hormone was only partially suppressed by SMS 201-995 in insulin-dependent diabetic subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
This study explored using SMS 201-995 to suppress growth hormone in diabetic retinopathy, finding it partially suppressed hormone levels and improved vision temporarily. Further research is needed for sustained effects in nonproliferative diabetic retinopathy.
Area of Science:
- Endocrinology
- Ophthalmology
- Metabolic disorders
Background:
- Diabetic retinopathy is a leading cause of blindness.
- Growth hormone (GH) is implicated in diabetic complications.
- Nonproliferative diabetic retinopathy (NPDR) requires effective management strategies.
Purpose of the Study:
- To assess the feasibility and effect of medical suppression of GH using SMS 201-995 in NPDR.
- To evaluate the impact of GH suppression on visual acuity and insulin requirements.
Main Methods:
- A study involving six insulin-dependent diabetic subjects with NPDR.
- Administration of the somatostatin analogue SMS 201-995 for eight weeks.
- Monitoring of 24-hour integrated plasma GH, insulin requirements, somatomedin-C, and visual acuity.
Main Results:
- SMS 201-995 partially suppressed GH levels by 47% (p < 0.01) and reduced insulin needs (p < 0.01).
- Visual acuity significantly improved during treatment (p < 0.05 for both eyes).
- Improvements in vision were temporary, reverting to baseline after treatment cessation.
Conclusions:
- Medical suppression of GH with SMS 201-995 is feasible but only partially effective in insulin-dependent diabetic subjects with NPDR.
- GH suppression shows potential for temporary visual acuity improvement.
- Further investigation into sustained GH suppression and its long-term effects on diabetic retinopathy is warranted.