Plasma cortisol suppression response in the South African black population with glaucoma

[Cortisol levels in plasma and aqueous humour of patients with steroid induced and other glaucomas]

The paper describes the role of endogenous glucocorticoids in the pathogenesis of open-angle glaucoma. As to steroid-induced glaucoma (SG), however, indicators of systemic and local cortisol metabolism are yet underinvestigated. Aim - to determine and compare systemic (plasma) and local (aqueous humour) cortisol concentrations in patients with SG and other types of glaucoma (OTG).

MATERIAL AND METHODS

A prospective analysis was conducted in 64 patients who underwent plasma and aqueous humor sampling. All the patients were divided into 4 groups: group 1 - 11 patients with steroid induced ocular hypertension (SOH) and SG; group 2 - 31 patients with OTG; group 3 - 10 patients on steroid therapy (ST) without a so called 'steroid response'; group 4 - the controls (12 patients with cataract).

RESULTS

The mean cortisol levels in plasma and aqueous humour were the following: 177.5±29.4 ng/ml and 53.1±12.2 ng/ml in patients with SOH and SG; 277.7±33.6 ng/ml and 44.6±4.4 ng/ml in patients with OTG; 125.2±28.1 ng/ml in patients on ST; 147.2±19.1 ng/ml and 29.8±3.2 ng/ml in the controls. The highest plasma and aqueous humour cortisol levels were found in groups 2 and 1, respectively.

CONCLUSION

Plasma and aqueous humour levels of cortisol appeared to be higher in glaucoma patients than in the controls. Taking into account the fact that plasma cortisol levels are higher in steroid responders, it is recommended that all patients on ST undergo cortisol testing.

Glucocorticoid therapy and ocular hypertension

The projected number of people who will develop age-related macular degeneration in estimated at 2020 is 196 million and is expected to reach 288 million in 2040. Also, the number of people with Diabetic retinopathy will grow from 126.6 million in 2010 to 191.0 million by 2030. In addition, it is estimated that there are 2.3 million people suffering from uveitis worldwide. Because of the anti-inflammatory properties of glucocorticoids (GCs), they are often used topically and/or intravitreally to treat ocular inflammation conditions or edema associated with macular degeneration and diabetic retinopathy. Unfortunately, ocular GC therapy can lead to severe side effects. Serious and sometimes irreversible eye damage can occur as a result of the development of GC-induced ocular hypertension causing secondary open-angle glaucoma. According to the world health organization, glaucoma is the second leading cause of blindness in the world and it is estimated that 80 million will suffer from glaucoma by 2020. In the current review, mechanisms of GC-induced damage in ocular tissue, GC-resistance, and enhancing GC therapy will be discussed.

Primary open-angle glaucoma and sensitivity to corticosteroids in vitro

Corticosteroid inhibition of mitogen induced lymphocyte transformation was studied in patients with definite or suspected primary open-angle plaucoma (POAG). Patients without glaucoma served as normal controls. From a dose response curve with prednisolone-21-PO4 or prednisolone the value of 50% inhibition (I50) was determined for each patient. In Series I it was necessary to disqualify 70% of the data whereas in Series II less than 5% were excluded. In Series I the median I50 (M X 10(-8) prednisolone-21-PO4) was 12 for 11 controls and 8 for 18 total POAG'S (p less than .01). In Series II the opposite result was obtained. The median I50 was 8 for 49 controls and 12 for 79 total POAG'S (p less than .01). In series II similar results were obtained with prednisolone. There was no difference between definite and suspected glaucoma patients. The cause of the discrepancy between the present two series and among the other published studies is not clear. The source of normal controls, from either an eye clinic or volunteer groups, may be a factor.