scholarly journals Candesartan Normalizes Changes in Retinal Blood Flow and p22phox in the Diabetic Rat Retina

2021 ◽  
Vol 28 (1) ◽  
pp. 86-97
Author(s):  
Randa S. Eshaq ◽  
Megan N. Watts ◽  
Patsy R. Carter ◽  
Wendy Leskova ◽  
Tak Yee Aw ◽  
...  
Keyword(s):  
Blood Flow ◽  
Diabetic Retinopathy ◽  
Angiotensin Ii ◽  
Nadph Oxidase ◽  
Calcium Release ◽  
Diabetic Rats ◽  
Retinal Blood Flow ◽  
Diabetic Rat ◽  
Angiotensin Ii Receptor ◽  
Tissue Levels

Angiotensin II has been implicated in the progression of diabetic retinopathy, which is characterized by altered microvasculature, oxidative stress, and neuronal dysfunction. The signaling induced by angiotensin II can occur not only via receptor-mediated calcium release that causes vascular constriction, but also through a pathway whereby angiotensin II activates NADPH oxidase to elicit the formation of reactive oxygen species (ROS). In the current study, we administered the angiotensin II receptor antagonist candesartan (or vehicle, in untreated animals) in a rat model of type 1 diabetes in which hyperglycemia was induced by injection of streptozotocin (STZ). Eight weeks after the STZ injection, untreated diabetic rats were found to have a significant increase in tissue levels of angiotensin converting enzyme (ACE; p < 0.05) compared to non-diabetic controls, a 33% decrease in retinal blood flow rate (p < 0.001), and a dramatic increase in p22phox (a subunit of the NADPH oxidase). The decrease in retinal blood flow, and the increases in retinal ACE and p22phox in the diabetic rats, were all significantly attenuated (p < 0.05) by the administration of candesartan in drinking water within one week. Neither STZ nor candesartan induced any changes in tissue levels of superoxide dismutase (SOD-1), 4-hydroxynonenal (4-HNE), or nitrotyrosine. We conclude that one additional benefit of candesartan (and other angiotensin II antagonists) may be to normalize retinal blood flow, which may have clinical benefits in diabetic retinopathy.

trans-Anethole attenuated renal injury and reduced expressions of angiotensin II receptor (AT1R) and TGF-β in streptozotocin-induced diabetic rats

Biochimie ◽  
2021 ◽  
Vol 185 ◽  
pp. 117-127
Author(s):  
Zahra Samadi-Noshahr ◽  
Alireza Ebrahimzadeh-Bideskan ◽  
Mosa-Al-Reza Hadjzadeh ◽  
Mohammad Naser Shafei ◽  
Hossein Salmani ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Renal Injury ◽  
Diabetic Rats ◽  
Angiotensin Ii Receptor

Retinal Vascular Implications of Ocular Hypertension

2021 ◽  
Author(s):  
Fidan Jmor ◽  
John C. Chen
Keyword(s):  
Blood Flow ◽  
Diabetic Retinopathy ◽  
Intraocular Pressure ◽  
Vascular Anatomy ◽  
Flow Regulation ◽  
Retinal Blood Flow ◽  
Vein Occlusion ◽  
Ocular Perfusion ◽  
The Relationship ◽  
Central Retinal Vein

In this chapter, we review the basics of retinal vascular anatomy and discuss the physiologic process of retinal blood flow regulation. We then aim to explore the relationship between intraocular pressure and retinal circulation, taking into account factors that affect retinal hemodynamics. Specifically, we discuss the concepts of ocular perfusion pressure, baro-damage to the endothelium and transmural pressure in relation to the intraocular pressure. Finally, we demonstrate the inter-relationships of these factors and concepts in the pathogenesis of some retinal vascular conditions; more particularly, through examples of two common clinical pathologies of diabetic retinopathy and central retinal vein occlusion.

Angiotensin II Receptor and Postreceptor Events in Adrenal Glomerulosa Cells from Streptozotocin-Induced Diabetic Rats with Hypoaldosteronism Division of Endocrinology

Endocrinology ◽  
1991 ◽  
Vol 129 (5) ◽  
pp. 2729-2733 ◽  
Author(s):  
SADAHIDE AZUKIZAWA ◽  
MIHOKO KANEKO ◽  
SHIGERU NAKANO ◽  
TOSHIKAZU KIGOSHI ◽  
KENZO UCHIDA ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Diabetic Rats ◽  
Angiotensin Ii Receptor ◽  
Glomerulosa Cells

Effect of Panretinal Photocoagulation on Retinal Blood Flow in Proliferative Diabetic Retinopathy

Ophthalmology ◽  
1986 ◽  
Vol 93 (5) ◽  
pp. 590-595 ◽  
Author(s):  
Juan E. Grunwald ◽  
Charles E. Riva ◽  
Alexander J. Brucker ◽  
Stephen H. Sinclair ◽  
Benno L. Petrig
Keyword(s):  
Blood Flow ◽  
Diabetic Retinopathy ◽  
Proliferative Diabetic Retinopathy ◽  
Retinal Blood Flow ◽  
Panretinal Photocoagulation

scholarly journals Role of the angiotensin II system in regulation of ovulation and blood flow in the rat ovary

Reproduction ◽  
2003 ◽  
pp. 425-435 ◽  
Author(s):  
K Mitsube ◽  
M Mikuni ◽  
M Matousek ◽  
U Zackrisson ◽  
M Brannstrom
Keyword(s):  
Blood Flow ◽  
Angiotensin Ii ◽  
Prostaglandin E ◽  
Receptor Subtypes ◽  
Angiotensin Ii Receptor ◽  
Doppler Flowmetry ◽  
Angiotensin Ii Receptor Subtypes ◽  
Specific Antagonist

The aim of the present study was to examine the roles of the angiotensin II receptor subtypes, AT(1) and AT(2), in ovulation, and to evaluate the contribution of angiotensin II-mediated pathways in regulation of ovarian blood flow. The AT(1)-specific antagonist, losartan, was administered alone or in combination with the AT(2)-specific antagonist, PD123319, to preovulatory rat ovaries perfused in vitro. Losartan (100 micromol l(-1)) did not affect the number of ovulations, whereas the combination of losartan (100 micromol l(-1)) and PD123319 (10 micromol l(-1)) inhibited ovulation. The angiotensin II antagonists did not affect the ovarian production of oestradiol, progesterone, prostaglandin E(2) (PGE(2)), PGF(2 alpha) or plasminogen activator activity. Ovarian nitric oxide production was inhibited by losartan. Ovarian blood flow was measured by laser Doppler flowmetry in vivo in preovulatory rat ovaries. Intrabursal injection of angiotensin II reduced ovarian blood flow of gonadotrophin-stimulated rats. Losartan had no effect on basal ovarian blood flow but completely blocked the angiotensin II-induced reduction. In contrast, treatment with PD123319 increased basal ovarian blood flow and failed to reverse the effect of exogenously administered angiotensin II, indicating that under physiological conditions, ovarian blood flow of the rat is negatively regulated by angiotensin II mainly through the action of AT(2). Taken together, these results indicate that two different types of angiotensin II receptor facilitate ovulation by cooperative mechanisms and that they regulate ovarian blood flow in a different manner.

Retinal Blood Flow Alterations During Progression of Diabetic Retinopathy

1983 ◽  
Vol 101 (2) ◽  
pp. 225-227 ◽  
Author(s):  
A. Yoshida ◽  
G. T. Feke ◽  
J. Morales-Stoppello ◽  
G. D. Collas ◽  
D. G. Goger ◽  
...  
Keyword(s):  
Blood Flow ◽  
Diabetic Retinopathy ◽  
Retinal Blood Flow

scholarly journals Nanoparticles C60 fullerene prevent reactive gliosis in retina of aged rats under hyperglycemia

2015 ◽  
Vol 6 (2) ◽  
pp. 113-118
Author(s):  
I. V. Prischepa ◽  
O. G. Prokushenkova ◽  
V. S. Nedzvetsky
Keyword(s):  
Diabetic Retinopathy ◽  
Glial Cells ◽  
Glycosylated Hemoglobin ◽  
Initial Period ◽  
Protective Action ◽  
Diabetic Rats ◽  
Water Soluble ◽  
Reactive Gliosis ◽  
C60 Fullerene ◽  
Diabetic Rat

Reactivation of glial cells, induced by metabolic disorders of glucose utilization and development of oxidative stress in retina under diabetes mellitus, is the key pathogenetic factor of diabetic retinopathy. Nanoparticles of C60 fullerene and some of their water-soluble derivates are known as one of the strongest antioxidants having neuroprotective effect in a number of pathologies and harmful influences. In the present study, for the first time, the effects of nanostructures of hydrated C60 fullerene (C60HyFn) on the expression and polypeptide composition of glial fibrillary acidic protein (GFAP) in retina of rats with streptozotocin (STZ)-induced diabetes have been evaluated. Using immunoblotting, 1.93-fold up-regulation of GFAP in diabetic rat retina as compared with control was shown, as a result of retinal glial cells reactivation induced by hyperglycemia. Increase in GFAP-immunolabeling associated with the reactive gliosis development in retina of diabetic rats was also confirmed by immuno-histochemical method. Consumption of C60HyFn solution (90 nM) as drinking water by diabetic rats for 12 weeks caused 1.51-fold decrease of GFAP level compared to untreated diabetic animals. In addition, C60HyFn caused statistically significant lowering of glycosylated hemoglobin concentration in blood serum of STZ-diabetic rats 1.58-fold. However, nanoparticles C60 did not affect neither insulin nor glucose levels in blood of diabetic rats. In conclusion, results obtained indicate that protective action of hydrated fullerene in the initial period of diabetic retinopathy of aged animals is realized through suppression of excessive activation of GFAP-positive retinal cells. 

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