Microbial Signatures in The Rodent Eyes With Retinal Dysfunction and Diabetic Retinopathy.

Purpose: The gut microbiome has been linked to disease pathogenesis through their interaction in metabolic, endocrine, and immune functions. The goal of this study was to determine whether the gut and plasma microbiota could transfer microbes to the retina in type 1 diabetic mice with retinopathy. Methods: We analyzed the fecal, plasma, whole globe, and retina microbiome in Akita mice and compared with age-matched wild-type (WT) mice using 16S rRNA sequencing and metatranscriptomic analysis. To eliminate the contribution of the ocular surface and plasma microbiome, mice were perfused with sterile saline solution, the whole globes were extracted, and the neural retina was removed under sterile conditions for retinal microbiome. Results: Our microbiome analysis revealed that Akita mice demonstrated a distinct pattern of microbes within each source: feces, plasma, whole globes, and retina. WT mice and Akita mice experienced transient bacteremia in the plasma and retina. Bacteria were identified in the retina of the Akita mice, specifically Corynebacterium, Pseudomonas, Lactobacillus, Staphylococcus, Enterococcus, and Bacillus. Significantly increased levels of peptidoglycan (0.036 ± 0.001 vs. 0.023 ± 0.002; P < 0.002) and TLR2 (3.47 ± 0.15 vs. 1.99 ± 0.07; P < 0.0001) were observed in the retina of Akita mice compared to WT. Increased IBA+ cells in the retina, reduced a- and b-waves on electroretinography, and increased acellular capillary formation demonstrated the presence of retinopathy in the Akita cohort compared to WT mice. Conclusions: Together, our findings suggest that transient bacteremia exists in the plasma and retina of both cohorts. The bacteria found in Akita mice are distinct from WT mice and may contribute to development of retinal inflammation and barrier dysfunction in retinopathy.

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.

Alterations in the gut bacterial microbiome in people with type 2 diabetes mellitus and diabetic retinopathy.

Gut bacterial microbiome dysbiosis in type 2 Diabetes Mellitus (T2DM) has been reported, but such an association with Diabetic Retinopathy (DR) is not known. We explored possible link between gut bacterial microbiome dysbiosis and DR. Using fecal samples of healthy controls (HC) and people with T2DM with/without DR, gut bacterial communities were analysed using 16S rRNA gene sequencing and data analysed using QIIME and R software. Dysbiosis in the gut microbiomes, at phyla and genera level, was observed in people with T2DM and DR compared to HC. People with DR exhibited greater discrimination from HC. Microbiomes of people with T2DM and DR were also significantly different. Both DM and DR microbiomes showed a decrease in anti-inflammatory, probiotic and other bacteria that could be pathogenic, compared to HC, and the observed change was more pronounced in people with DR. This is the first report demonstrating dysbiosis in the gut microbiome (alteration in the diversity and abundance at the phyla and genera level) in people with DR compared to HC. Such studies would help in developing novel and targeted therapies to improve treatment of DR.

Gut mycobiomes are altered in people with type 2 Diabetes Mellitus and Diabetic Retinopathy.

Studies have documented dysbiosis in the gut mycobiome in people with Type 2 diabetes mellitus (T2DM). However, it is not known whether dysbiosis in the gut mycobiome of T2DM patients would be reflected in people with diabetic retinopathy (DR) and if so, is the observed mycobiome dysbiosis similar in people with T2DM and DR. Gut mycobiomes were generated from healthy controls (HC), people with T2DM and people with DR through Illumina sequencing of ITS2 region. Data were analysed using QIIME and R software. Dysbiotic changes were observed in people with T2DM and DR compared to HC at the phyla and genera level. Mycobiomes of HC, T2DM and DR could be discriminated by heat map analysis, Beta diversity analysis and LEfSE analysis. Spearman correlation of fungal genera indicated more negative correlation in HC compared to T2DM and DR mycobiomes. This study demonstrates dysbiosis in the gut mycobiomes in people with T2DM and DR compared to HC. These differences were significant both at the phyla and genera level between people with T2DM and DR as well. Such studies on mycobiomes may provide new insights and directions to identification of specific fungi associated with T2DM and DR and help developing novel therapies for Diabetes Mellitus and DR.

Screening and identification of gut anaerobes (Bacteroidetes) from human diabetic stool samples with and without retinopathy in comparison to control subjects.

Studies have reported a reciprocal interaction between metabolic disorders and the human gut microbial composition. However, more information is still needed concerning the gut microbiome related to metabolic disorders such as Diabetes. The aim of the present study was to reveal whether stool samples collected from normal individuals and from diabetic subjects with or without retinopathy differ in their gut microbial composition. Data showed higher Bacteroides ratio in diabetic groups gut composition with no significant difference of bacterial strains in diabetic subjects with or without retinopathy compared to lean (control) individuals gut microbiota. These findings indicated that the gut microbiota is altered in accordance to the presence of metabolic disorders. However, further studies have to be elaborated in terms of gut microbial composition with diabetes.

Diabetic gut microbiota dysbiosis as an inflammaging and immunosenescence condition that fosters progression of retinopathy and nephropathy.

The increased prevalence of type 2 diabetes mellitus (T2DM) and life expectancy of diabetic patients fosters the worldwide prevalence of retinopathy and nephropathy, two major microvascular complications that have been difficult to treat with contemporary glucose-lowering medications. The gut microbiota (GM) has become a lively field research in the last years; there is a growing recognition that altered intestinal microbiota composition and function can directly impact the phenomenon of ageing and age-related disorders. In fact, human GM, envisaged as a potential source of novel therapeutics, strongly modulates host immunity and metabolism. It is now clear that gut dysbiosis and their products (e.g. p-cresyl sulfate, trimethylamine­N­oxide) dictate a secretory associated senescence phenotype and chronic low-grade inflammation, features shared in the physiological process of ageing ("inflammaging") as well as in T2DM ("metaflammation") and in its microvascular complications. This review provides an in-depth look on the crosstalk between GM, host immunity and metabolism. Further, it characterizes human GM signatures of elderly and T2DM patients. Finally, a comprehensive scrutiny of recent molecular findings (e.g. epigenetic changes) underlying causal relationships between GM dysbiosis and diabetic retinopathy/nephropathy complications is pinpointed, with the ultimate goal to unravel potential pathophysiological mechanisms that may be explored, in a near future, as personalized disease-modifying therapeutic approaches.

The Role of Microbiota in Retinal Disease.

The ten years since the first publications on the human microbiome project have brought enormous attention and insight into the role of the human microbiome in health and disease. Connections between populations of microbiota and ocular disease are now being established, and increased accessibility to microbiome research and insights into other diseases is expected to yield enormous information in the coming years. With the characterization of the ocular microbiome, important insights have already been made regarding corneal and conjunctival tissues. Roles for non-ocular microbiomes in complex retinal diseases are now being evaluated. For example, the gut microbiome has been implicated in the pathogenesis of uveitis. This short review will summarize the few studies linking gut or oral microbiota to diabetic retinopathy (DR), glaucoma, and age-related macular degeneration (AMD). We will also conjecture where the most significant findings still remain to be elucidated. Finally, we will propose the gut-retina axis, related but distinct from the gut-brain axis.

Higher titers of anti-Chlamydia pneumoniae IgG in diabetic retinopathy: a cross-sectional study.

BACKGROUND: Chronic inflammation has a role in the pathogenesis of diabetic retinopathy. Infection with intracellular organisms may incite chronic inflammation. This study was conducted to investigate the association between previous infection with Chlamydia pneumoniae (an intracellular microorganism) and diabetic retinopathy. METHODS: Patients with type 2 diabetes mellitus (30-60 years old) and age-matched normal controls were recruited. Patients with history of cardiovascular or cerebrovascular disease, recent pulmonary infection and the presence of age-related macular degeneration were excluded from the study. Complete ophthalmic examinations were performed. Fasting blood sugar and haemoglobin levels were measured in diabetic patients and controls, and HgbA1c , blood urea nitrogen, creatinine and 24-h urine protein were measured in diabetic patients. Anti-C. pneumoniae IgG (enzyme-linked immunosorbent assay) was measured in the sera of all participants. RESULTS: A total of 215 type 2 diabetic patients and 243 normal healthy controls were included. Anti-C. pneumoniae IgG titers were higher in patients affected by diabetic retinopathy than participants without retinopathy (74.78 ± 33.38 vs 66.18 ± 31.40, p = 0.028). Diabetic patients with diabetic retinopathy also had higher titers than diabetic patients without diabetic retinopathy (74.78 ± 33.38 vs 66.11 ± 33.41, p = 0.042). Of different variables including age, body mass index, haemoglobin level, glycated haemoglobin level, fasting blood sugar, mean arterial pressure and blood urea nitrogen, only age (r = 0.17; p = 0.001) and body mass index (r = 0.15; p = 0.003) were correlated with anti-C. pneumoniae IgG levels. In regression analysis, the presence of diabetic retinopathy was still a determinant of the antibody level (p = 0.03). CONCLUSION: Anti-C. pneumoniae IgG titers were higher in patients with diabetic retinopathy, which may indicate a role of this infection in the pathogenesis of diabetic retinopathy.

Bilateral endogenous endophthalmitis associated with methicillin sensitive Staphylococcus aureus (MSSA) related tenosynovitis: case report.

Endogenous endophthalmitis is a rare, devastating intraocular infection associated with poor outcome often from late diagnosis. We present a case report of acute onset bilateral endogenous endophthalmitis caused by Methicillin Sensitive Staphylococcus Aureus causing tenosynovitis of carpometacarpal joint in a 64 year old man with Type II Diabetes Mellitus. To the best of our knowledge, this is the first case report of endogenous endophthalmitis following tenosynovitis. This case also highlights the fact that prompt diagnosis and treatment is the key for good outcome.

Role of Helicobacter pylori in causation of diabetic gastropathies and non-gastrointestinal complications in type 2 diabetes.

A cross-sectional case-control study was conducted in 80 diabetic patients, to evaluate the incidence of gastropathy by endoscopy in type 2 diabetes mellitus. An association between Helicobacter pylori infection and non-gastrointestinal complication of diabetes mellitus was also looked into. Gastric biopsies were subjected to rapid urease test for demonstration of Helicobacter pylori. The fasting blood glucose levels among Helicobacter pylori positive diabetes were 175 +/- 36.5 mg %, and in Helicobacter pylori negative diabetics were 138 +/- 39.4 mg %. The prevalence of endoscopically detectable gastro-intestinal complications were higher in Helicobacter pylori infected diabetics (odd's ratio 4:2; p < 0.05). The total prevalence of Helicobacter pylori positive in diabetics by rapid urease test was statistically significant (p < 0.05). Coronary heart disease was more prevalent in diabetics with Helicobacter pylori infection than those without Helicobacter pylori (57%). The prevalence of H. pylori positivity in other complications such as peripheral vascular diseases, cerebrovascular diseases was not significant. The association between nephropathy, retinopathy and neuropathy with Helicobacter pylori, was also observed and the strong association was seen in diabetic retinopathy (p < 0.001), diabetic neuropathy (p < 0.01) and nephropathy (p < 0.001).

Helicobacter pylori prevalence in diabetes mellitus patients with dyspeptic symptoms and its relationship to glycemic control and late complications.

BACKGROUND: There are contradictory reports on Helicobacter pylori prevalence and its relationship to late complications of diabetes mellitus (DM). The aim of this study was to determine the prevalence of H. pylori infection in type 2 DM patients and to evaluate the relationship between H. pylori infection and the glycemic control, late complications. MATERIAL AND METHOD: A total of 141 type 2 DM patients and 142 nondiabetic subjects with upper gastrointestinal symptoms were enrolled in the study. All patients underwent upper gastrointestinal endoscopy with biopsy specimens obtained from gastric antrum and corpus. H. pylori status was evaluated in each patient by both the rapid urease test and histopathological examination. Plasma glucose, HbA1c, microalbuminuria in 24 h collected urine, electroneuromyography, and fundoscopic examinations were performed in all subjects. RESULTS: The prevalence of H. pylori infection was 61.7% and 58.5%, respectively, among type 2 diabetic patients and nondiabetic controls and was not statistically significant (P = 0.577). The duration of diabetes, fasting blood glucose and haemoglobin A1c levels, nephropathy and retinopathy prevalence did not differ significantly between the two groups (diabetics versus nondiabetics). There was no late complication in 60.3% of the type 2 diabetic patients as compared to at least one late complication in the remainders. A statistically significant correlation was found between H. pylori infection and the presence of neuropathy (P = 0.021). CONCLUSIONS: The prevalence of H. pylori infection did not differ significantly between the diabetic patients and nondiabetic controls. Interestingly, diabetics with H. pylori infection had a higher incidence of neuropathy, although there was no association between the duration and regulation of diabetes, retinopathy, nephropathy and H. pylori status.

[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.

Association of Helicobacter pylori infection with cardiovascular and cerebrovascular disease in diabetic patients.

OBJECTIVE: Infection by Helicobacter pylori has been epidemiologically linked to some extradigestive conditions, including ischemic heart disease. Diabetic patients are an at-risk population for cardiovascular and thrombo-occlusive cerebral disease. The aim of the study was to examine a possible relationship between H. pylori infection and cardiovascular or cerebrovascular disease in diabetic patients. RESEARCH DESIGN AND METHODS: This was a cross-sectional case-control study with 127 diabetic patients (both IDDM and NIDDM). Special emphasis was placed on the detection of clinical macro- and microvascular complications, cardiovascular risk factors, acute phase reactants, and serological markers of increased cardiovascular disease risk. H. pylori infection was assessed through the determination of specific Ig-G titers, measured by a commercial enzyme-linked immunosorbent assay. RESULTS: Coronary heart disease was more prevalent in diabetic patients with than without H. pylori (odds ratio [OR] 4.07; 95% CI 1.21-13.6; P < 0.05). A history of thrombo-occlusive cerebral disease was also more frequent in H. pylori-positive diabetic patients (OR 4.8; 95% CI 1.24-18.51; P < 0.05). Other complications such as peripheral arteriopathy, advanced nephropathy, neuropathy, or retinopathy were no differently distributed according to serological status. Alterations in the levels of the following acute-phase reactants and blood chemistry determinations were significantly more profound in H. pylori-positive diabetic patients: high fibrinogen (P < 0.05), high erythrocyte sedimentation rate (P < 0.001), high triglycerides (P < 0.001), and low HDL cholesterol (P < 0.001). There values were also more deeply altered in H. pylori-positive diabetic patients with a history of coronary heart disease, thrombo-occlusive cerebral disease, or both, when compared with H. pylori-positive diabetic patients without those complications. CONCLUSIONS: Our data indicate a possible association of H. pylori infection and the development of coronary heart disease, thrombo-occlusive cerebral disease, or both, in diabetic patients. The importance of this link is highlighted by the possibility of an effective intervention against H. pylori infection.