Lack of inducible nitric oxide synthases attenuates leukocyte-endothelial cell interactions in retinal microcirculation

Iwama, Daisuke; Miyahara, Shinya; Tamura, Hiroshi; Miyamoto, Kazuaki; Hirose, Fuyuki; Yoshimura, Nagahisa

doi:10.1136/bjo.2007.131151

Cited by 6 publications

(6 citation statements)

References 21 publications

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“…Previous studies have demonstrated the feasibility of using microscopic imaging systems for the real-time analysis of retinal vascular function in rats [31–33] and mice [34–37]. Our experiments used a high-resolution fundus microscope system to focus on the primary branches of the CRA in living mice while delivering vasoactive compounds systemically.…”

Section: Discussionmentioning

confidence: 99%

The role of arginase I in diabetes-induced retinal vascular dysfunction in mouse and rat models of diabetes

et al. 2012

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Aims/hypothesis A reduction in retinal blood flow occurs early in diabetes and is likely to be involved in the development of diabetic retinopathy. We hypothesise that activation of the arginase pathway could have a role in the vascular dysfunction of diabetic retinopathy. Methods Experiments were performed using a mouse and rat model of streptozotocin (STZ)-induced diabetes for in vivo and ex vivo analysis of retinal vascular function. For in vivo studies, mice were infused with the endothelial-dependent vasodilator acetylcholine (ACh) or the endothelial-independent vasodilator sodium nitroprusside (SNP), and vasodilation was assessed using a fundus microscope. Ex vivo assays included pressurised vessel myography, western blotting and arginase activity measurements. Results ACh-induced retinal vasodilation was markedly impaired in diabetic mice (40% of control values), whereas SNP-induced dilation was not altered. The diabetes-induced vascular dysfunction was markedly blunted in mice lacking one copy of the gene encoding arginase I and in mice treated with the arginase inhibitor 2(S)-amino-6-boronohexanoic acid. Ex vivo studies performed using pressure myography and central retinal arteries isolated from rats with STZ-induced diabetes showed a similar impairment of endothelial-dependent vasodilation that was partially blunted by pretreatment of the isolated vessels with another arginase inhibitor, (S)-2-boronoethyl-l-cysteine. The diabetes-induced vascular alterations were associated with significant increases in both arginase I protein levels and total arginase activity. Conclusions/interpretation These results indicate that, in the mouse and rat model, diabetes-induced increases in arginase I were involved in the diabetes-induced impairment of retinal blood flow by a mechanism involving vascular endothelial cell dysfunction.

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Section: Discussionmentioning

confidence: 99%

The role of arginase I in diabetes-induced retinal vascular dysfunction in mouse and rat models of diabetes

et al. 2012

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“…By this time, leukocytes were not visible traveling in the blood vessels (due to the washout effect (Iwama et al, 2008), and leukocytes appeared outside major vessels. The number of leukocytes counted in the still image was taken to represent the number of leukocytes that left the vasculature and extravasated into the retina.…”

Section: Detailed Methodsmentioning

confidence: 99%

“…Leukocyte adherence to the endothelial lining of blood vessels is a key component of inflammation. Leukocyte fluorography has been extensively used in the past twenty years (Janssen et al, 1994; Nishiwaki et al,1995; Nishiwaki et al, 1996; Iwama et al, 2008; Miyahara et al, 2004); however, fluorescent markers, visualization techniques, and recording methods have differed between studies. To date there have been no detailed protocol papers relating to leukocyte fluorography in mice, resulting in a paucity of standards for leukocyte transit (velocity, adherence, extravasation) in the retina.…”

Section: Introductionmentioning

confidence: 99%

“…Even when AOLF was used with commercially available SLOs, a video monitoring system developed in-house developed was required for recording and analysis. While leukocyte fluorography has been tested in mice, it has either relied on alternative dyes which required removal of leukocytes prior to staining and then reintroducing the leukocytes back into the mouse (Xu et al, 2003), or relied on in house video recording devices that required separate set up (Iwama et al, 2008; Miyahara et al 2004). This paper presents a method with simple administration of the fluorescent agent (tail vein injection of AO) and a commercially available imaging system (Heidelberg Spectralis) which contains within its software video recording capabilities.…”

Section: Introductionmentioning

confidence: 99%

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Acridine orange leukocyte fluorography in mice

Cahoon¹,

Olson²,

Nielson³

et al. 2014

Experimental Eye Research

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Simultaneous non-invasive visualization of blood vessels and nerves in patients can be obtained in the eye. The retinal vasculature is a target of many retinopathies. Inflammation, readily manifest by leukocyte adhesion to the endothelial lining, is a key pathophysiological mechanism of many retinopathies, making it a valuable and ubiquitous target for disease research. Leukocyte fluorography has been extensively used in the past twenty years; however, fluorescent markers, visualization techniques, and recording methods have differed between studies. The lack of detailed protocol papers regarding leukocyte fluorography, coupled with lack of uniformity between studies, has led to a paucity of standards for leukocyte transit (velocity, adherence, extravasation) in the retina. Here, we give a detailed description of a convenient method using acridine orange (AO) and a commercially available scanning laser ophthalmoscope (SLO, HRA-OCT Spectralis) to view leukocyte behavior in the mouse retina. Normal mice are compared to mice with acute and chronic inflammation. This method can be readily adopted in many research labs.

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“…Second, NO not only induces vasorelaxation but also promotes leukocyte-endothelial cell interactions. These actions all lead to activated neutrophils and monocyte/macrophage aggregation in inflamed tissues [ 16 , 17 ]. Third, NO and many downstream oxidation products are highly cytotoxic to retinal cells and other ocular tissues.…”

Section: Introductionmentioning

confidence: 99%

Expression Profile of Cationic Amino Acid Transporters in Rats with Endotoxin-Induced Uveitis

Hsu

Chang

Yang

et al. 2016

Mediators of Inflammation

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Purpose. The transcellular arginine transportation via cationic amino acid transporter (CAT) is the rate-limiting step in nitric oxide (NO) synthesis, which is crucial in intraocular inflammation. In this study, CAT isoforms and inducible nitric oxide synthase (iNOS) expression was investigated in endotoxin-induced uveitis (EIU). Methods. EIU was induced in Lewis rats by lipopolysaccharide (LPS) injection. In the treatment group, the rats were injected intraperitoneally with the proteasome inhibitor bortezomib before EIU induction. After 24 hours, leukocyte quantification, NO measurement of the aqueous humor, and histopathological examination were evaluated. The expression of CAT isoforms and iNOS was determined by reverse transcription-polymerase chain reaction, western blotting, and immunofluorescence staining. Nuclear factor-kappa B (NF-κB) binding activity was evaluated by electrophoretic mobility shift assay. The mouse macrophage cell line RAW 264.7 was used to validate the in vivo findings. Results. LPS significantly stimulated iNOS, CAT-2A, and CAT-2B mRNA and protein expression but did not affect CAT-1 in EIU rats and RAW 264.7 cells. Bortezomib attenuated inflammation and inhibited iNOS, CAT-2A, and CAT-2B expression through NF-κB inhibition. Conclusions. CAT-2 and iNOS, but not CAT-1, are specifically involved in EIU. NF-κB is essential in the induction of CAT-2 and iNOS in EIU.

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Lack of inducible nitric oxide synthases attenuates leukocyte-endothelial cell interactions in retinal microcirculation

Cited by 6 publications

References 21 publications

The role of arginase I in diabetes-induced retinal vascular dysfunction in mouse and rat models of diabetes

The role of arginase I in diabetes-induced retinal vascular dysfunction in mouse and rat models of diabetes

Acridine orange leukocyte fluorography in mice

Expression Profile of Cationic Amino Acid Transporters in Rats with Endotoxin-Induced Uveitis

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