Prevention of Endotoxin-Induced Uveitis in Rats by Benfotiamine, a Lipophilic Analogue of Vitamin B1

Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555-0647, USA.
Investigative ophthalmology & visual science (Impact Factor: 3.4). 02/2009; 50(5):2276-82. DOI: 10.1167/iovs.08-2816
Source: PubMed


To study the amelioration of ocular inflammation in endotoxin-induced uveitis (EIU) in rats by benfotiamine, a lipid-soluble analogue of thiamine.
EIU in Lewis rats was induced by subcutaneous injection of lipopolysaccharide (LPS) followed by treatment with benfotiamine. The rats were killed 3 or 24 hours after LPS injection, eyes were enucleated, aqueous humor (AqH) was collected, and the number of infiltrating cells, protein concentration, and inflammatory marker levels were determined. Immunohistochemical analysis of eye sections was performed to determine the expression of inducible-nitric oxide synthase (iNOS), cyclooxygenase (Cox)-2, protein kinase C (PKC), and transcription factor NF-kappaB.
Infiltrating leukocytes, protein concentrations, and inflammatory cytokines and chemokines were significantly elevated in the AqH of EIU rats compared with control rats, and benfotiamine treatment suppressed these increases. Similarly increased expression of inflammatory markers iNOS and Cox-2 in ciliary body and retinal wall was also significantly inhibited by benfotiamine. The increased phosphorylation of PKC and the activation of NF-kappaB in the ciliary body and in the retinal wall of EIU rat eyes were suppressed by benfotiamine.
These results suggest that benfotiamine suppresses oxidative stress-induced NF-kappaB-dependent inflammatory signaling leading to uveitis. Therefore, benfotiamine could be used as a novel therapeutic agent for the treatment of ocular inflammation, especially uveitis.

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    • "In the ocular tissue, exposure to LPS is known to induce the breakdown of the blood–aqueous barrier, which leads to protein transudate in the anterior chamber, infiltration of macrophages and neutrophils into the eye, and production of multiple proinflammatory mediators, including cytokines and chemokines, such as TNF-α, IL-6, MCP-1 and ICAM-1 [36], [41], [43], [44]. The overproduction of these cytokines is mediated through NF-κB [45], [46]. These clinical, biochemical, immunological and histological characteristics make EIU a suitable in vivo model to evaluate the therapeutic efficacy of drugs for the treatment of inflammatory ocular diseases in humans. "
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    ABSTRACT: Pancreatitis-associated protein (PAP) is a pancreatic secretory protein belongs to the group VII of C-type lectin family. Emerging evidence suggests that PAP plays a protective effect in inflammatory diseases. In the present study, we newly identified a 16-amino-acid peptide (named PAPep) derived from C-type lectin-like domain (CTLD) of human PAP with potent anti-inflammatory activity using both in vivo and in vitro assays. We assessed the anti-inflammatory effect of PAPep on endotoxin-induced uveitis (EIU) in rats and demonstrated that intravitreal pretreatment of PAPep concentration-dependently attenuated clinical manifestation of EIU rats, reduced protein leakage and cell infiltration into the aqueous humor (AqH), suppressed tumor necrosis factor (TNF)-α, interleukin (IL)-6, intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein (MCP)-1 production in ocular tissues, and improved histopathologic manifestation of EIU. Furthermore, PAPep suppressed the LPS-induced mRNA expression of TNF-α and IL-6 in RAW 264.7 cells, inhibited protein expression of ICAM-1 in TNF-α-stimulated human umbilical vein endothelial cells (HUVECs) as well as U937 cells adhesion to HUVECs. Western blot analysis in ocular tissues and different cell lines revealed that the possible mechanism for this anti-inflammatory effect of PAPep may depend on its ability to inhibit the activation of NF-kB signaling pathway. Our studies provide the first evidence that the sequence of PAPep is within the critically active region for the anti-inflammatory function of PAP and the peptide may be a promising candidate for the management of ocular inflammatory diseases.
    Preview · Article · Dec 2011 · PLoS ONE
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    • "In experimental research, injection of endotoxins such as lipopolysacharide (LPS) is used to induce uveitis in susceptible animal species such as rats and mice [3,4]. LPS-induced uveitis in rodents mimics human uveitis, and is used as an animal model of pathogenesis of uveitis to evaluate the therapeutic efficacy of drugs [5]. Increased inflammatory markers such as cyclooxygenase-2 (COX-2) and inducible-nitric oxide synthase (iNOS) result in the breakdown of blood-ocular barrier and infiltration of leukocytes into ocular tissues, leading to LPS-induced uveitis [6]. "
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    ABSTRACT: ABSTRACT: Lutein is an important eye-protective nutrient. This study investigates the protective effects and mechanisms of lutein on lipopolysaccharides (LPS)-induced uveitis in mice. Lutein, suspended in drinking water at a final concentration of 12.5 and 25 mg/mL, was administered to mice at 0.1 mL/10 g body weight for five consecutive days. Control and model group received drinking water only. Uveitis was induced by injecting LPS (100 mg per mouse) into the footpad in the model and lutein groups on day 5 after the last drug administration. Eyes of the mice were collected 24 hours after the LPS injection for the detection of indicators using commercial kits and reverse transcription-polymerase chain reaction. LPS-induced uveitis was confirmed by significant pathological damage and increased the nitric oxide level in eye tissue of BALB/C mice 24 hours after the footpad injection. The elevated nitric oxide level was significantly reduced by oral administration of lutein (125 and 500 mg/kg/d for five days) before LPS injection. Moreover, lutein decreased the malondialdehyde content, increased the oxygen radical absorbance capacity level, glutathione, the vitamin C contents and total superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Lutein further increased expressions of copper-zinc SOD, manganese SOD and GPx mRNA. Conclusion The antioxidant properties of lutein contribute to the protection against LPS-induced uveitis, partially through the intervention of inflammation process.
    Full-text · Article · Oct 2011 · Chinese Medicine
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    • "However, no reports are available that show benfotiamine supplementation prevents sepsis complications in animal or human studies. We have recently reported that the anti-oxidative and anti-inflammatory properties of benfotiamine in preventing the LPS-induced cytotoxicity in macrophages as well as preventing the ocular inflammation in rats [24] [25]. "
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    ABSTRACT: Benfotiamine, a lipid-soluble analogue of vitamin B1, is a potent antioxidant that is used as a food supplement for the treatment of diabetic complications. Our recent study (U.C. Yadav et al., Free Radic. Biol. Med. 48:1423-1434, 2010) indicates a novel role for benfotiamine in the prevention of bacterial endotoxin, lipopolysaccharide (LPS)-induced cytotoxicity and inflammatory response in murine macrophages. Nevertheless, it remains unclear how benfotiamine mediates anti-inflammatory effects. In this study, we investigated the anti-inflammatory role of benfotiamine in regulating arachidonic acid (AA) pathway-generated inflammatory lipid mediators in RAW264.7 macrophages. Benfotiamine prevented the LPS-induced activation of cPLA2 and release of AA metabolites such as leukotrienes, prostaglandin E2, thromboxane 2 (TXB2), and prostacyclin (PGI2) in macrophages. Further, LPS-induced expression of AA-metabolizing enzymes such as COX-2, LOX-5, TXB synthase, and PGI2 synthase was significantly blocked by benfotiamine. Furthermore, benfotiamine prevented the LPS-induced phosphorylation of ERK1/2 and expression of transcription factors NF-κB and Egr-1. Benfotiamine also prevented the LPS-induced oxidative stress and protein-HNE adduct formation. Most importantly, compared to specific COX-2 and LOX-5 inhibitors, benfotiamine significantly prevented LPS-induced macrophage death and monocyte adhesion to endothelial cells. Thus, our studies indicate that the dual regulation of the COX and LOX pathways in AA metabolism could be a novel mechanism by which benfotiamine exhibits its potential anti-inflammatory response.
    Preview · Article · Oct 2011 · Free Radical Biology and Medicine
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