Gut microbiota: A potential therapeutic target for management of diabetic retinopathy?

Diabetic Retinopathy (DR) is one of the main complications of Diabetes Mellitus (DM), drastically impacting individuals of working age over the years, being one of the main causes of blindness in the world. The existing therapies for its treatment consist of measures that aim only to alleviate the existing clinical signs, associated with the microvasculature. These treatments are limited only to the advanced stages and not to the preclinical ones. In response to a treatment with little resolution and limited for many patients with DM, investigations of alternative therapies that make possible the improvement of the glycemic parameters and the quality of life of subjects with DR, become extremely necessary. Recent evidence has shown that deregulation of the microbiota (dysbiosis) can lead to low-grade, local and systemic inflammation, directly impacting the development of DM and its microvascular complications, including DR, in an axis called the intestine-retina. In this regard, the present review seeks to comprehensively describe the biochemical pathways involved in DR as well as the association of the modulation of these mechanisms by the intestinal microbiota, since direct changes in the microbiota can have a drastic impact on various physiological processes. Finally, emphasize the strong potential for modulation of the gut-retina axis, as therapeutic and prophylactic target for the treatment of DR.

[Study of mycobiota in the healthy conjunctiva of diabetics who reside in the urban area of the city of São Paulo, Brazil]. / Estudo da micobiota em conjuntiva sadia de diabéticos, residentes na área urbana da cidade de São Paulo-Brasil.

PURPOSE: To determine the mycobiota of the healthy conjunctiva in diabetic individuals, according to diabetes type, age, sex, disease time, type of treatment, and stage of diabetic retinopathy of the individuals. To identify the anemophilus mycobiota in the sampling rooms. METHODS: A cross-sectional study was carried out on 803 diabetics who reside in the urban area of São Paulo-SP/Brazil. Sabouraud's dextrose agar culture with chloramphenicol was used for primoisolation, and the key of De Hoog was used to identify filamentous fungi. RESULTS: Of the evaluated diabetics, 6.6% (53/803) presented type 1 diabetes and 93.4% (750/803) type 2. The positive cultures for fungi in the conjunctiva of diabetics was 4.2% (34/803), with 1.9% (1/53) in type 1 diabetics and 4.4% (33/740) in type 2 diabetics (p=0.720). With respect to the presence or not of isolated fungi, there was no statistically significant association regarding age (p=0.575), sex (p=0.517), disease time (p=0.633), type of treatment (p=0.422), and diabetic retinopathy stage (p=0.655) of the tested individuals. The identified fungi were all filamentous: Aspergillus spp. represented 59.5% (25/42) of isolations and 47.6% (20/42) of isolated species were Aspergillus niger. Growth of anemophilus fungi occurred in the air of the room and coincidences were observed between the isolated species from the air and those from the conjunctiva. CONCLUSIONS: Presence of mycobiota in healthy conjunctivas of diabetics was identified, with no significant association between the greater number of positive fungi isolations and the type of diabetes, age, sex, disease type, type of treatment, and stage of diabetic retinopathy. In the collection rooms, anemophilus mycobiota was identified.

Estudo da micobiota em conjuntiva sadia de diabéticos, residentes na área urbana da cidade de São Paulo - Brasil / Study of mycobiota in the healthy conjunctiva of diabetics who reside in the urban area of the city of São Paulo, Brazil

OBJETIVOS: Determinar a micobiota de conjuntiva sadia em indivíduos diabéticos, segundo tipo de diabetes, idade, sexo, tempo de doenca, tipo de tratamento e estádio da retinopatia. Estabelecer a micobiota anemófila nas salas de colheita. MÉTODOS: Estudo transversal de 803 diabéticos residentes na zona urbana de São Paulo - SP/Brasil. Foi usado para primo-isolamento o meio de cultivo ágar Sabouraud dextrose com cloranfenicol e para identificacão dos fungos filamentosos a chave de De Hoog. RESULTADOS: Dos diabéticos avaliados, 6,6 por cento (53/803) apresentavam diabetes tipo 1 e 93,4 por cento (750/803) tipo 2. Os cultivos positivos para fungos em conjuntiva de diabéticos foi 4,2 por cento (34/803), sendo 1,9 por cento (1/53) nos diabéticos tipo 1 e 4,4 por cento (33/740) nos diabetes tipo 2 (p=0,720). Não foi verificada associacão estatisticamente significante quanto à presenca ou não de isolamentos de fungos em relacão idade (p=0,575), sexo (p=0,517), tempo de doenca (p=0,633), tipo de tratamento (p=0,422) e estádio de retinopatia diabética (p=0,655) desses indivíduos. Todos os fungos identificados foram filamentosos: Aspergillus spp. representou 59,5 por cento (25/42) dos isolamentos sendo 47,6 por cento (20/42) Aspergillus niger. Ocorreu crescimento de fungos anemófilos do ar ambiente da sala, observando-se coincidências entre as espécies isoladas no ar e na conjuntiva. CCONCLUSÕES: Foi identificada presenca de micobiota em conjuntiva sadia de diabéticos, não havendo associacão entre a maior positividade de isolamentos fúngicos e o tipo de diabetes, idade, sexo, tempo de doenca, tipo de tratamento e estádio da retinopatia diabética. Nas salas de colheita foi identificada micobiota anemófila.

Aerobic bacterial conjunctival flora in diabetic patients.

OBJECTIVE: To study the aerobic conjunctival flora of diabetic patients and its relation to the presence and level of diabetic retinopathy and the duration of the disease. METHODS: One hundred three patients from the diabetic retinopathy screening program of the Federal University of São Paulo with no evidence of ocular surface disease were included. The diabetic patient cohort was compared with 60 nondiabetic subjects. All patients underwent slit-lamp evaluation, conjunctival scrapings, and indirect ophthalmoscopy. RESULTS: The frequency of positive conjunctival cultures was significantly higher in the diabetic group (94.18%) than in the nondiabetic group (73.33%). Among diabetic patients, a significantly higher frequency of positive cultures was detected in those with diabetic retinopathy than in those without retinopathy. Neither the duration of the diabetes nor the hypoglycemic therapy correlated with the culture results. Coagulase-negative Staphylococcus was the most common microorganism isolated, and its identification was more frequent in patients with retinopathy than in those without diabetic retinopathy. CONCLUSION: Diabetic patients have a significantly higher number of positive conjunctival cultures. The presence of diabetic retinopathy was correlated with an increase in positive cultures and a higher proportion of coagulase-negative Staphylococcus.