Pro-Inflammatory Effects of Indoxyl Sulfate in Mice: Impairment of Intestinal Homeostasis and Immune Response

Abstract

The intestines are recognized as the main source of chronic inflammation in chronic kidney disease (CKD) and, among other cells, macrophages are involved in modulating this process as well as in the impaired immune response which also occurs in CKD patients. In this study, we evaluated the effect of Indoxyl Sulfate (IS), a protein bound uremic toxin poorly eliminated by hemodialysis, on inflammatory, oxidative stress and pro-apoptotic parameters, at the intestinal level in mice, on intestinal epithelial cells (IEC-6) and on primary murine peritoneal macrophages. C57BL/6J mice were treated with IS (800 mg/kg i.p.) for 3 or 6 h and histopathological analysis showed that IS induced intestinal inflammation and increased cyclooxygenase-2 (COX-2), nitrotyrosine and Bax expression in intestinal tissue. In IEC-6 cells, IS (125–1000 µM) increased tumor necrosis factor-α levels, COX-2 and inducible nitric oxide synthase expression and nitrotyrosine formation. Moreover, IS increased pro-oxidant, pro-inflammatory and pro-apoptotic parameters in peritoneal macrophages from IS-treated mice. Also, the serum concentration of IS and pro-inflammatory levels of cytokines resulted increased in IS-treated mice. Our results indicate that IS significantly contributes to affect intestinal homeostasis, immune response, and to induce a systemic pro-inflammatory state thus highlighting its potential role as therapeutic target in CKD patients.

Curcumin Modulates Nitrosative Stress, Inflammation, and DNA Damage and Protects against Ochratoxin A-Induced Hepatotoxicity and Nephrotoxicity in Rats

“…No: M1U539 G, L10, Bio-Optica, Milan, Italy). The following primary antibodies were used: Polyclonal Rabbit Anti-CD3 (Code n. ab5690, Abcam, Cambridge, UK) at 1:100 in PBS, Monoclonal Mouse Anti-CD79 (Clone HM57, Dako, Santa Clara, CA, USA) at 1:100 in PBS, and Polyclonal Rabbit Anti-Iba1 (Code n. 019-19741, WAKO, Osaka, Japan) at 1:1000 in PBS [ 34 ]. Slides were examined and photographed with a light microscope (Nikon Eclipse E600 Tokyo, Japan) equipped with a microphotography system Nikon digital camera (DMX1200 Tokyo, Japan).…”

Zebrafish Model-Based Assessment of Indoxyl Sulfate-Induced Oxidative Stress and Its Impact on Renal and Cardiac Development

“…IS exposure has been reported to increase pro-oxidation and pro-inflammatory reactions in a mouse study [ 30 ]. In our study, the results showed that both ROS scavenging and blockade of the MAPK pathway significantly reduced the mRNA levels of the proinflammatory genes il-1b and cox2a, whose expression was induced by IS ( Figure 6 ), suggesting that IS may cause inflammation through oxidative stress and the MAPK pathway.…”

“…Moreover, a mouse-based model study investigating IS-induced oxidative stress revealed that a significant fluorescence signal of H2DCF-DA (an H 2 O 2 -sensitive fluorescent probe) was detectable in primary mouse peritoneal macrophages after 3 h and 6 h of IS treatment, and the expression of the antioxidant enzyme SOD-2 was reduced [ 30 ]. Additionally, another study showed that injection of unilaterally nephrectomized mice with IS significantly increased the levels of the lipid peroxidation indicator malondialdehyde (MDA) in mouse urine and serum.…”

“…A study by Marzocco et al indicated that IS has proinflammatory effects on C57BL/6J mice and increases the expression of cox-2 and Bax [ 30 ]. Another study revealed that neuroinflammation [ 46 ], serum IL-1 protein levels, and prefrontal cortical tissue IL-1 mRNA levels are elevated in IS-treated mice.…”

Chronic Kidney Disease-Associated Itch (CKD-aI) in Children—A Narrative Review

“…IS stimulates oxidative stress [ 125 , 126 , 127 , 128 ], whereby contributing to endothelial senescence [ 129 ]. Several studies focused on proinflammatory properties of IS [ 130 , 131 ] and its influence on the function of macrophages [ 132 , 133 , 134 ], with the latter aspect linking IS to the development of atherosclerosis. Clinical studies in adult people constituted IS as an important compound related to the progression of CKD, associated CVD, infections, glucose intolerance and mortality [ 117 , 135 , 136 , 137 , 138 , 139 , 140 ].…”