Interstitial cystitis (IC) is a chronic inflammatory disease of the bladder without bacterial infection or any other identifiable pathological cause. Symptoms include frequent and painful urination, nocturnal urination, and chronic pelvic pain. The diagnosis of the disease is complex, and no treatment is available that achieves long-term effects. This is primarily due to the currently unknown causes of the onset and progression of the disease. The pathogenesis of interstitial cystitis is characterized by damage to the urothelium and increased permeability of the blood-urine barrier, resulting in the passage of undesirable molecules from the urine into the bladder wall or deeper, leading to inflammation. Oxidative stress, which is characteristic of many chronic inflammatory diseases, also contributes to this. Studies also indicate reduced expression of tight junction and adhesion proteins in patients with IC. Given this, it is necessary to find a treatment that affects several different processes and biological pathways, with anti-inflammatory and antioxidant effects, while also influencing the function of the blood-urine barrier.
One potential treatment option is taurine. Taurine (2-aminoethanesulfonic acid) is a non-proteinogenic amino acid found in various animal tissues, playing a crucial role in many essential biological processes. In humans, taurine is synthesized during the metabolism of methionine and cysteine in hepatocytes. A growing number of studies confirm that taurine alleviates inflammation and oxidative stress. It achieves this by inhibiting the production of inflammatory mediators and promoting the expression of antioxidant enzymes. Additionally, taurine strengthens intercellular junctions in various epithelial barriers, thereby enhancing their protective function.
Our research focused on the impact of taurine on gene expression in SV-HUC-1 cell lines. We studied whether taurine affects the expression levels of anti-inflammatory and antioxidant genes, as well as genes encoding intercellular junction proteins, compared to cells exposed only to an inflammation trigger (glucose oxidase). For this purpose, we employed quantitative PCR (qPCR). The results were also verified at the protein level using enzyme-linked immunosorbent assay (ELISA) and fluorescence microscopy.
The results suggest that taurine has anti-inflammatory effects, as taurine supplementation reduced the expression of the IL-6 inflammatory cytokine gene and the secretion of IL-6 and IL-8 into the supernatants of cells exposed to oxidative stress. Taurine also increased the expression of the gene for the antioxidant enzyme catalase (CAT), while it had no effect on the expression of other studied genes involved in oxidative stress. Based on qPCR analysis and fluorescence microscopy, we also confirmed that taurine increases the expression of the ZO-1 tight junction gene and protein and the E-cadherin adhesion protein, which could suggest its effect on improving blood-urine barrier function.
Further clinical and experimental studies in animal models could confirm the potential of taurine as a therapeutic agent for the treatment of interstitial cystitis.
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