Diabetes mellitus en niños y adolescentes: complicaciones crónicas y enfermedades asociadas

Polyol pathway: A possible mechanism of diabetes complications in the eye

In complex diseases such as diabetes mellitus, the causative agents include various serum factors such as glucose, aldose reductase, oxygen-free radicals, advanced glycation end products, protein kinase-C and growth factors. The polyol pathway is a pathway of glucose metabolism and is regarded as an important element in the pathogenesis of refractive changes, cataract formation and diabetic retinopathy in individuals with diabetes mellitus. The focus of this review is on the role of the polyol pathway in the pathogenesis of diabetic complications in the eye. The first enzyme (aldose reductase) in the polyol pathway reduces glucose to sorbitol. The second enzyme (sorbitol dehydrogenase) converts sorbitol to fructose. The accumulation of sorbitol and fructose in the crystalline lens and retina leads to the generation of oxidative stress. Oxidative stress is the imbalance between levels of reactive oxygen species and the antioxidant defence in a biological system, and it results in tissue damage. How hyperglycaemia leads to oxidative stress is not clear but could be through a combination of increased levels of reactive oxygen species and decreased capacity of the cellular antioxidant system. Oxidative stress causes the development of diabetic complications that are seen clinically.

[Outcome differences in pediatric patients with type 1 diabetes mellitus depending on their HLA-DQ genotypes]

BACKGROUND AND OBJECTIVE

Our hypothesis is that there is a relationship between the short term outcomes of pediatric patients with type I diabetes mellitus and their HLA-DQ genotypes.

PATIENTS AND METHOD

We performed a descriptive epidemiologic study of 129 children and adolescents under 16 years old with type 1 diabetes mellitus. We studied their HLA DQ genotypes and classified them into groups of diabetogenic risk. We studied general clinic and analytic parameters at onset of the disease and during a period of 3 years, and the development of associated chronic complications.

RESULTS

In total, 93.8% of our patients had diabetes-risk HLA-DQ genotypes. Onset of the disease occurred earlier in patients who belonged to risk group III, and they had less pancreatic reserve. During the follow-up period, significant differences in systolic and diastolic blood pressure were found in patients in risk group III, and in diastolic blood pressure in patients in risk group I.

CONCLUSIONS

Patients in risk group III have an onset at a lower age and present significant differences in systolic and diastolic blood pressure during the follow up period.

Juvenile diabetes eye complications and treatment

BACKGROUND/AIM

Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia. The aim of this study was to explore the prognosis of patients with juvenile DM regarding diabetic eye complications, as well as the course of the diabetic eye disease related to the treatment undertaken.

METHODS

The study series involved 33 patients with juvenile DM during the period 1992-2007. The influence of the following factors on the course of the disease was estimated: age, the age of the disease onset, time when eye complications appeared, treatment modalities.

RESULTS

Of the total of 33 diabetics 15 patients were followed for 10 or more years and 18 from 5 to 9 years. At the time of their first visit the mean age was 23.12 +/- 6.39 and the mean duration of DM was 17.42 +/- 7.42 years. On their first visit, 7 eyes were without any complication. Most of the patients already developed clinical signs of proliferative diabetic retinopathy (41.39%), the signs of nonproliferative diabetic retinopathy (13.13%) and macula involvement (10.10%). Diabetic cataract was found in 8.8% as well as tractional retinal detachment. Eleven out of 66 eyes were with vitreous hemorrhage. Two patients (5.5%) suffered neovascular glaucoma. There was 1 (2.2%) patient with developed rubeosis iridis and simplex glaucoma. Panretinal photocoagulation was performed in 65% of patients, focal photocoagulation in 15%, 12% patients underwent pars plana vitrectomy and 4% had cataract surgery with intraocular lens implantation and peripheral retinal kryopexy.

CONCLUSION

Total vision loss due to eye complications of juvenile DM may be prevented if timely diagnosed with regular check ups and early treatment.