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Quantitative assessment of textural features in the early detection of diabetic retinopathy with optical coherence tomography angiography. Photodiagnosis Photodyn Ther 2022; 41:103214. [PMID: 36460230 DOI: 10.1016/j.pdpdt.2022.103214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/08/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022]
Abstract
The diagnostic power of the textural features and fractal dimension (FD) for early detection of diabetic retinopathy (DR) were quantitatively evaluated with optical coherence tomography angiography (OCTA). 41 normal healthy OD eyes (age: 46.41 ± 13.69), and 10 diabetic OD eyes (age: 60.90 ± 13.46) in the early stages of DR (mild or moderate non-proliferative diabetic retinopathy (NPDR)) were employed. Four retinal vascular plexuses including nerve fiber layer vascular plexus (NFLVP), superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP) were generated by using OCTA. The FD and the five textural features including contrast, correlation, entropy, energy, and homogeneity in four parafoveal sectors were extracted from OCTA images. The factor of aging on textural features and FD was evaluated based on the comparisons among five normal healthy subgroups. Our results showed that FD in superior sector of NFLVP and in nasal sector of ICP had the significant decreases when comparing the older healthy subgroup (age range: 60-69) with the younger healthy subgroup (age range: 20-29). Our results also indicated that the correlation did not show the significant differences in all sectors of the four retinal sublayers among the normal healthy subgroups except in the temporal sector in NFLVP. Furthermore, our results indicated that the correlation in nasal and inferior sectors in SVP can effectively differentiate diabetic patients in early stages of DR from normal healthy subjects with the highest AUROC values. In our study, the specific textural feature - correlation can effectively stage the early DR, which may contribute to the diagnosis of DR in clinic practice.
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Luo J, Zhao Q, Li Z, Chen L. Multiple roles of apelin/APJ system in eye diseases. Peptides 2022; 152:170767. [PMID: 35181348 DOI: 10.1016/j.peptides.2022.170767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/11/2022] [Accepted: 02/12/2022] [Indexed: 10/19/2022]
Abstract
Apelin is an endogenous ligand of G protein-coupled receptor (APJ), and they compose apelin/APJ system. Apelin/APJ system is widely distributed in tissues and plays pleiotropic roles. Attractively, more emphasis has recently been placed on the effects of apelin/APJ system in eye diseases, such as retinopathy of prematurity (ROP), diabetic retinopathy (DR) and diabetic macular edema (DME). In this review, we elaborated the roles of apelin/APJ system in the pathophysiological processes of eye. Concretely, apelin/APJ system induces retinal gliosis and angiogenesis. Hypoxia-inducible factors (HIFs) are involved in apelin/APJ system-triggered ROP progress. Apelin/APJ system mediates DR-induced retinopathy. Apelin/APJ system maintains retinal functions and health by protecting Müller cells from apoptosis. Apelin/APJ system suppresses the NMDA-induced retinal ganglion cell (RGC) loss to protect optic nerve damage. Overall, apelin/APJ system is a potential therapeutic target for eye disease.
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Affiliation(s)
- Jingshun Luo
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of tumor microenvironment responsive drug research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China
| | - Qun Zhao
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhiyue Li
- Department of Orthopedics, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China.
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of tumor microenvironment responsive drug research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China.
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Marques IP, Madeira MH, Messias AL, Martinho ACV, Santos T, Sousa DC, Figueira J, Cunha-Vaz J. Different retinopathy phenotypes in type 2 diabetes predict retinopathy progression. Acta Diabetol 2021; 58:197-205. [PMID: 33025221 PMCID: PMC7889686 DOI: 10.1007/s00592-020-01602-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/03/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE To characterize the progression in retinopathy severity of different phenotypes of mild nonproliferative diabetic retinopathy (NPDR) in patients with type 2 diabetes. DESIGN AND METHODS Patients with type 2 diabetes and mild NPDR (ETDRS 20 or 35) were followed in a 5-year longitudinal study. Examinations, including color fundus photography (CFP) and optical coherence tomography (OCT and OCTA), were performed at baseline, 6 months and then annually. Phenotype classification was performed based on microaneurysm turnover (MAT, on CFP) and central retinal thickness (CRT, on OCT). Phenotype A is characterized by low MAT (< 6) and normal CRT; Phenotype B by low MAT (< 6) and increased CRT; and Phenotype C by higher MAT (≥ 6) with or without increased CRT. ETDRS grading of seven fields CFP was performed at the initial and last visits. RESULTS Analysis of ETDRS grade step changes showed significant differences in diabetic retinopathy (DR) progression between the different phenotypes (p < 0.001). Of the 66 participants with phenotype A only 2 eyes (3%) presented 2-or-more-step worsening. None of the 50 participants characterized as phenotype B developed 2-step worsening, whereas 13 eyes (23.2%) characterized as phenotype C had 2-or-more-steps worsening. Phenotype C presents the higher risk for 2-or-more step worsening (OR: 15.94 95% CI: 3.45-73.71; p < 0.001) and higher sensitivity, correctly identifying 86.7% of cases at risk (AUC: 0.84 95% CI: 0.72-0.96; p < 0.001). Diabetic retinopathy severity progression was associated with HbA1c (p = 0.019), LDL levels (p = 0.043), and ocular factors as MAT (p = 0.010), MA formation rate (p = 0.014) and MA disappearance rate (p = 0.005). Capillary closure at 5-year follow-up, identified by lower vessel density (VD) on OCTA, was also associated with diabetic DR severity progression (p = 0.035). CONCLUSIONS Different DR phenotypes in type 2 diabetes show different risks of retinopathy progression. Phenotype C is associated with increased HbA1c values and presents a higher risk of a 2-or-more-step worsening of the ETDRS severity score.
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Affiliation(s)
- Inês P. Marques
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Maria H. Madeira
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Ana L. Messias
- Dentistry Department, Faculty of Medicine, University of Coimbra, 3000-075 Coimbra, Portugal
| | - António C.-V. Martinho
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Torcato Santos
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - David C. Sousa
- Ophthalmology Department, Hospital de Santa Maria, 1649-028 Lisbon, Portugal
- Vision Sciences Study Center, CECV, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
- Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
| | - João Figueira
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal
- Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
| | - José Cunha-Vaz
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal
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Santos T, Warren LH, Santos AR, Marques IP, Kubach S, Mendes LG, Sisternes LD, Madeira MH, Durbin M, Cunha-Vaz JG. Swept-source OCTA quantification of capillary closure predicts ETDRS severity staging of NPDR. Br J Ophthalmol 2020; 106:712-718. [PMID: 33355147 PMCID: PMC9046755 DOI: 10.1136/bjophthalmol-2020-317890] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/20/2020] [Accepted: 12/05/2020] [Indexed: 11/12/2022]
Abstract
Purpose To test whether a single or composite set of parameters evaluated with optical coherence tomography angiography (OCTA), representing retinal capillary closure, can predict non-proliferative diabetic retinopathy (NPDR) staging according to the gold standard ETDRS grading scheme. Methods 105 patients with diabetes, either without retinopathy or with different degrees of retinopathy (NPDR up to ETDRS grade 53), were prospectively evaluated using swept-source OCTA (SS-OCTA, PlexElite, Carl Zeiss Meditec) with 15×9 mm and 3×3 mm angiography protocols. Seven-field photographs of the fundus were obtained for ETDRS staging. Eyes from age-matched healthy subjects were also imaged as control. Results In eyes of patients with type 2 diabetes without retinopathy or ETDRS levels 20 and 35, retinal capillary closure was in the macular area, with predominant alterations in the parafoveal retinal circulation (inner ring). Retinal capillary closure in ETDRS stages 43–53 becomes predominant in the retinal midperiphery with vessel density average values of 25.2±7.9 (p=0.001) in ETDRS 43 and 23.5±3.4 (p=0.001) in ETDRS 47–53, when evaluating extended areas of 15×9 protocol. Combination of acquisition protocols 3×3 mm and 15×9 mm, using SS-OCTA, allows discrimination between eyes with mild NPDR (ETDRS 10, 20, 35) and eyes with moderate-to-severe NPDR (ETDRS grades 43–53). Conclusions Retinal capillary closure, quantified by SS-OCTA, can identify NPDR severity progression. It is located mainly in the perifoveal retinal capillary circulation in the initial stages of NPDR, whereas the retinal midperiphery is predominantly affected in moderate-to-severe NPDR.
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Affiliation(s)
- Torcato Santos
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
| | | | - Ana Rita Santos
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal.,Department of Orthoptics, School of Health, Polytechnic of Porto, Porto, Portugal
| | - Inês Pereira Marques
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal.,Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | | | - Luís G Mendes
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
| | | | - Maria H Madeira
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal.,Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Mary Durbin
- R&D, Carl Zeiss Meditec, Dublin, California, USA
| | - Jose G Cunha-Vaz
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal .,Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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Teruya K, Yamashita M, Tominaga R, Nagira T, Shim SY, Katakura Y, Tokumaru S, Tokumaru K, Barnes D, Shirahata S. Fermented milk, Kefram-Kefir enhances glucose uptake into insulin-responsive muscle cells. Cytotechnology 2011; 40:107-16. [PMID: 19003111 DOI: 10.1023/a:1023926407877] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Diminution of insulin-responses in the target organ is the primary cause of non-insulin dependent diabetes mellitus (NIDDM).It is thought to be correlated to the excessive production of reactive oxygen species (ROS). In this article, we attempted to evaluate whether fermented milk, Kefram-Kefir known as an antioxidant, reduces the cellular ROS levels and can stimulate the glucose uptake in L6 skeletal muscle cells. Water-soluble or chloroform/methanol-extracted fractions from Kefram-Kefir were examined to evaluate the glucose uptake ability of L6 myotubes.As a result, the water-soluble fraction augmented the uptake of glucose in L6 myotubes both in the presence and absence of insulin stimulation. Estimation of intracellular ROS level revealed that the water-soluble fraction of Kefram-Kefir reduced the intracellular ROS level on both the undifferentiated and differentiated L6 cells. Especially, glucose uptake was augmented up to six times with the addition of water-soluble fraction in the insulin-stimulated L6 myotubes. Glucose transport determination revealed that the active agent in Kefram-Kefir was resistant to autoclave and stable in pH range from 4 to 10, and the small molecule below the molecular weight of 1000. Furthermore, this augmentation was inhibited in the presence of phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor wortmannin. Considering together with the reports that PI 3-kinase is locatedin the insulin signaling pathway and the participation in the translocation of glucose transporter 4 to the cell membrane, it is suggested that the water-soluble fraction of Kefram-Kefir activates PI 3-kinase or other upstream molecules in the insulin signaling pathway, which resulted in the augmentation of glucose uptake and its specific inhibition by wortmannin.
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Affiliation(s)
- Kiichiro Teruya
- Department of Genetic Resources Technology, Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan,
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Abstract
AIM To examine knowledge and management of diabetes by older people. METHODS A representative sample of 1047 people with Type 2 diabetes, aged 75 years and over, were asked a series of questions relating to their diabetes management and their understanding of self management. The impact of cognitive impairment and socio-economic status were assessed. RESULTS The majority of people, 1015 (96.9%), were under the care of a health professional and 1018 (97.2%) were taking insulin, tablets, controlling their diet or a combination. Cognitive impairment (Mini-Mental State Examination ≤ 23) was found in 235 (22.5%) people. Recent eye, foot and dietician assessment was reported by 813 (77.7%), 836 (79.7%) and 326 (31.1%) people, respectively. A quarter overall and 70% of those taking insulin tested their blood glucose. In the insulin group, 78 (54.2%) reported hypoglycaemia and those with cognitive impairment gave more incorrect responses when asked about diabetes management. Socio-economic status made very little difference to any of these outcomes. CONCLUSIONS Most older people with diabetes, regardless of their socio-economic status, are under the care of a healthcare professional and use medication or diet to manage their disease. Large numbers also attend foot and eye examinations. However, over one fifth of older people with diabetes have cognitive impairment. Older people had a reasonable understanding of their diabetes management but this was worse in those people with cognitive impairment.
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Affiliation(s)
- J Hewitt
- London School of Hygiene and Tropical Medicine and Portsmouth Hospitals Trust, Queen Alexandra Hospital, Portsmouth, UK.
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How to improve screening for diabetic retinopathy: The Burgundy experience. DIABETES & METABOLISM 2010; 36:114-9. [DOI: 10.1016/j.diabet.2009.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 08/26/2009] [Accepted: 09/02/2009] [Indexed: 11/18/2022]
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Bosco A, Lerário AC, Soriano D, Dos Santos RF, Massote P, Galvão D, Franco ACHM, Purisch S, Ferreira AR. [Diabetic retinopathy]. ACTA ACUST UNITED AC 2005; 49:217-27. [PMID: 16184249 DOI: 10.1590/s0004-27302005000200007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Diabetic retinopathy is a frequently observed complication in both type 1 and type 2 diabetes, specially in patients with long term disease and poor glicemic control. Irreversible visual loss appears at the final stages of diabetic retinopathy and it is considered one of the most tragic of diabetic complications. It is also considered an important factor of morbidity and has a high economical impact once it is the leading cause of blindness. The pathophysiology of the retinal microvascular alterations is related to the chronic hyperglycemia that leads to the following circulatory disturbances: loss of vascular tonus, increase in vascular permeability, edema and exudation, with vascular obstruction and ischemia that stimulates neovascularization, which may lead to fibrous retraction and vitreous hemorrhages with retinal detachment. Recent studies have indicated that the strict glicemic and blood pressure controls are effective in reducing or blocking the progression of retinopathy. Up to now no pharmacological agents have shown to be effective in preventing or reducing neovascularization and visual loss. Presently, the most effective available treatment for proliferative retinopathy is laser photocoagulation. Further studies are needed to obtain new products and technologies that could effectively prevent or block retinopathy progression.
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Affiliation(s)
- Adriana Bosco
- Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo.
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Suzuki T, Oba K, Igari Y, Matsumura N, Inuzuka Y, Kigawa Y, Matsuura Y, Ajiro Y, Okazaki K, Nakano H. Relation of apolipoprotein (a) phenotypes to diabetic retinopathy in elderly type 2 diabetes. J NIPPON MED SCH 2002; 69:31-8. [PMID: 11847507 DOI: 10.1272/jnms.69.31] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aim of this study was to clarify the relationship between apolipoprotein (a) (apo (a) ) phenotypes and diabetic retinopathy in elderly type 2 diabetes. Serum Lp (a) concentrations and apo (a) phenotypes were analyzed in 250 diabetic patients aged 60 to 88 years old. Apo (a) phenotypes were classified into 7 subtypes (F, B, S1, S2, S3, S4, O (Null) ) by the method SDS electrophoresis with Western blotting. Patients were divided into two groups according to their apo (a) phenotypes:a low molecular weight (LMW) Lp (a) group, and a high molecular weight (HML) Lp (a) group. Patients were classified as having one of 4 types of diabetic retinopathy: no retinopathy (R0), simple retinopathy (R1), pre-proliferative retinopathy (R2), and proliferative retinopathy (R3). There was a significant association between serum Lp (a) levels and severity of diabetic retinopathy (p<0.001). A gradual trend toward increasing serum Lp (a) levels was observed across the groups (from R0 to R3). A significantly greater percentage of LMW Lp (a) was observed in the R1, R2, and R3 groups than in the R0 group (42.9% (p<0.001), 27.0% (p<0.01), and 27.3% (p<0.05) vs. 10.4%). Multiple logistic regression analysis revealed that duration of diabetes and LMW Lp (a) are independent risk factors for diabetic retinopathy. These results provide significant evidence that LMW Lp (a) contributes to an increased risk of diabetic retinopathy in elderly type 2 diabetes.
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Affiliation(s)
- Tatsuya Suzuki
- Division of Geriatric Medicine, Nippon Medical School, Tokyo, Japan
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Ryder JW, Chibalin AV, Zierath JR. Intracellular mechanisms underlying increases in glucose uptake in response to insulin or exercise in skeletal muscle. ACTA PHYSIOLOGICA SCANDINAVICA 2001; 171:249-57. [PMID: 11412137 DOI: 10.1046/j.1365-201x.2001.00827.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This review will provide insight on potential intracellular signalling mechanisms by which insulin and exercise/contraction increases glucose metabolism and gene expression. Glucose transport, the rate limiting step in glucose metabolism, is mediated by glucose transporter 4 (GLUT4) and can be activated in skeletal muscle by two separate and distinct signalling pathways; one stimulated by insulin and the second by muscle contractions. Impaired insulin action on whole body glucose uptake is a hallmark feature of type II (non-insulin-dependent) diabetes mellitus. Defects in insulin signal transduction through the insulin-receptor substrate-1/phosphatidylinositol 3-kinase pathway are associated with reduced insulin-stimulated glucose transporter 4 translocation and glucose transport activity in skeletal muscle from type II diabetic patients. Studies performed using glucose transporter 4-null mice show that this glucose transporter isoform plays a major role in mediating exercise-stimulated glucose uptake in skeletal muscle. Level of physical exercise has been linked to improved glucose homeostasis and enhanced insulin sensitivity. Exercise training leads to alterations in expression and activity of key proteins involved in insulin signal transduction. These changes may be related to increased signal transduction through the mitogen-activated protein kinase (MAPK) signalling cascades. Because MAPK is associated with increased transcriptional activity, these signalling cascades are candidates for these exercise-induced changes in protein expression. Understanding the molecular mechanism for the activation of signal transduction pathways will provide a link for defining new strategies to enhance glucose metabolism and improve health in the general population.
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Affiliation(s)
- J W Ryder
- Department of Clinical Physiology, Karolinska Hospital, and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Abstract
Neural tissue is entirely dependent on glucose for normal metabolic activity. Since glucose stores in the brain and retina are negligible compared to glucose demand, metabolism in these tissues is dependent upon adequate glucose delivery from the systemic circulation. In the brain, the critical interface for glucose transport is at the brain capillary endothelial cells which comprise the blood-brain barrier (BBB). In the retina, transport occurs across the retinal capillary endothelial cells of the inner blood-retinal barrier (BRB) and the retinal pigment epithelium of the outer BRB. Because glucose transport across these barriers is mediated exclusively by the sodium-independent glucose transporter GLUT1, changes in endothelial glucose transport and GLUT1 abundance in the barriers of the brain and retina may have profound consequences on glucose delivery to these tissues and major implications in the development of two major diabetic complications, namely insulin-induced hypoglycemia and diabetic retinopathy. This review discusses the regulation of brain and retinal glucose transport and glucose transporter expression and considers the role of changes in glucose transporter expression in the development of two of the most devastating complications of long-standing diabetes mellitus and its management.
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Affiliation(s)
- A K Kumagai
- Department of Internal Medicine, Michigan Diabetes Research and Training Center, University of Michigan Medical School, Ann Arbor, MI 48109-0678, USA.
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12
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Abstract
Diabetic retinopathy is the commonest cause of blindness amongst individuals of working age. The onset of retinopathy is variable. Regular ophthalmic screening is essential in order to detect treatable lesions early. Retinal laser therapy is highly effective in slowing the progression of retinopathy and in preventing blindness. As the sufferers of diabetes mellitus, the commonest endocrine disorder, now constitute approximately 1-2% of Western populations, concerted multidisciplinary effort must be made towards cost-effective community screening by the medical community.
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Affiliation(s)
- D A Infeld
- Department of Ophthalmology, University of Birmingham, Birmingham and Midland Eye Centre, UK
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13
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O'shea JG. Screening for diabetic retinopathy, the leading cause of blindness among Australians of working‐age. Clin Exp Optom 1998. [DOI: 10.1111/j.1444-0938.1998.tb06766.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- John G O'shea
- Department of Ophthalmology University of Birmingham
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14
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Kumagai AK, Vinores SA, Pardridge WM. Pathological upregulation of inner blood-retinal barrier Glut1 glucose transporter expression in diabetes mellitus. Brain Res 1996; 706:313-7. [PMID: 8822374 DOI: 10.1016/0006-8993(95)01335-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The pathological changes in the retinal microvasculature characteristic of diabetic retinopathy (DR) are the result of chronic exposure to elevated blood glucose. Since glucose entry into the microvascular endothelial cells comprising the inner blood-retinal barrier (BRB) is mediated by the GLUT1 glucose transporter, changes in GLUT1 expression on the inner BRB in long-standing diabetes mellitus may have a direct impact on the subsequent development of retinopathic changes. In the present study, quantitative immunogold electron microscopy for GLUT1 was employed on ultrathin cross-sections of postmortem retina specimens from 3 individuals with long-standing diabetes and minimal or no clinical retinopathy and from 2 non-diabetic individuals without ocular disorders. In the non-diabetic retinal capillaries, GLUT1 immunogold was distributed asymmetrically between the lumenal and ablumenal membranes with a lumenal-to-ablumenal ratio of 1 to 1.7. In the diabetic microvessels, a bimodal distribution pattern of GLUT1 immunoreactivity was observed. In 17 of 40 of the diabetic microvessels examined, the density and distribution of GLUT1 was no different from that of the non-diabetic vessels; however, in a subpopulation of the diabetic microvessels (23 of 40), a dramatic increase in GLUT1 immunoreactivity on the lumenal and albumenal membrane and in the cytoplasm was noted. On the lumenal membrane, the increased expression of immunoreactive GLUT1 was more than 18 times that of the non-diabetic microvessels. These findings demonstrate that localized upregulation of GLUT1 expression at the inner BRB occurs in long-standing diabetes mellitus with minimal or no clinical retinopathy and suggest that this upregulation may serve to amplify the deleterious effects of chronic hyperglycemia on the retinal microvasculature.
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Affiliation(s)
- A K Kumagai
- Department of Medicine, UCLA School of Medicine 90095-1682, USA
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