Experimental rat model for acute tubular injury induced by high water hardness and high water fluoride: efficacy of primary preventive intervention by distilled water administration

Fluoride Binding Potential of Selected Phytochemicals: A Pilot Study

Fluoride (F-) contamination in drinking water is a major global concern. According to several studies, India and China are the most affected by the presence of excess F-. Long-time exposure to F- concentrations above 1.5 ppm can lead to hard and soft tissue fluorosis (F- toxicity). There are no effective cure or treatment for fluorosis and the condition is almost irreversible. Considering water to be the prime media through which F- reaches humans, maintaining optimal F- levels in water remains the only possible remedy. F- endemic areas have adapted several conventional defluoridation techniques to resolve the issue. Among these, adsorption with plant compounds is widely used for F- removal. Studies have shown that plant metabolites can ameliorate the toxic effects of F-. Based on this, we attempt to elucidate the potential binding and electrochemical bio-sensing properties of selected phytochemicals towards F-. The focus of the present work is to evaluate the interactions of phytochemicals with F-; for which, the binding studies of phytochemicals with F- have been elaborated by UV-visible spectroscopy and emission techniques. Benesi-Hildebrand's (BH) plot was used to calculate the binding constant (CUR - 34.9 × 103 (M-1), QUER - 13 × 103 (M-1), ESC -6.3 × 103 (M-1), FIS - 5.36 × 103 (M-1) and PCA -1.5 × 103 (M-1), and detection limit (CUR - 1.54 × 10-7 M, QUER - 0.156 × 10-6 M, ESC - 0.221 × 10-6 M, FIS - 0.175 × 10-6 M, and PCA - 5.8 × 10-6 M) for the F-:phytochemical mixtures. Further, the binding characteristics were confirmed using 1H-NMR titration experiments. Our findings highlight the potential of phytochemicals as effective binding agents for F-, thereby reducing its bioavailability.

Exposure to Sri Lanka's local groundwater in a CKDu prevalent area causes kidney damage in zebrafish

How local groundwater induces chronic kidney disease of unknown etiology (CKDu) in Sri Lanka is still elusive. This study aims to elucidate the impacts of Sri Lanka's local groundwater in a CKDu prevalent area and reveal the possible pathogenic mechanism of CKDu using zebrafish models. The drinking water from the local underground well in Vavuniya was sampled and the water quality parameters including Na⁺, Mg²⁺, K⁺, Ca²⁺, Cl^-, NO^3-, SO₄^2-, and F^- were analyzed. Then, local groundwater exposure to zebrafish larvae and 293T cells was performed, and water with high hardness and fluoride was prepared as parallel groups. Our result showed that exposure to Sri Lanka's local groundwater caused developmental toxicity, kidney damage, and pronephric duct obstruction as well as abnormal behavior in zebrafish. Similar results were also found after exposure to water with high hardness and fluoride in zebrafish. Further, the expression levels of marker genes related to renal development and functions (foxj1a, dync2h1, pkd2, gata3, and slc20a1) were significantly altered, which is also confirmed in the 293T cells. Taken together, those results indicated that Sri Lanka's local groundwater in a CKDu prevalent area could cause kidney damage, implying that high water hardness and fluorine might be the inducible environmental factors for the etiological cause of CKDu.

Effect of Fluoride on Cytotoxicity Involved in Mitochondrial Dysfunction: A Review of Mechanism

Fluoride is commonly found in the soil and water environment and may act as chronic poison. A large amount of fluoride deposition causes serious harm to the ecological environment and human health. Mitochondrial dysfunction is a shared feature of fluorosis, and numerous studies reported this phenomenon in different model systems. More and more evidence shows that the functions of mitochondria play an extremely influential role in the organs and tissues after fluorosis. Fluoride invades into cells and mainly damages mitochondria, resulting in decreased activity of mitochondrial related enzymes, weakening of protein expression, damage of respiratory chain, excessive fission, disturbance of fusion, disorder of calcium regulation, resulting in the decrease of intracellular ATP and the accumulation of Reactive oxygen species. At the same time, the decrease of mitochondrial membrane potential leads to the release of Cyt c, causing a series of caspase cascade reactions and resulting in apoptosis. This article mainly reviews the mechanism of cytotoxicity related to mitochondrial dysfunction after fluorosis. A series of mitochondrial dysfunction caused by fluorosis, such as mitochondrial dynamics, mitochondrial Reactive oxygen species, mitochondrial fission, mitochondrial respiratory chain, mitochondrial autophagy apoptosis, mitochondrial fusion disturbance, mitochondrial calcium regulation are emphasized, and the mechanism of the effect of fluoride on cytotoxicity related to mitochondrial dysfunction are further explored.

The Utility of Novel Renal Biomarkers in Assessment of Chronic Kidney Disease of Unknown Etiology (CKDu): A Review

Chronic Kidney Disease (CKD) is a globally prevalent non-communicable disease with significant mortality and morbidity. It is typically associated with diabetes and hypertension; however, over the last two decades, an emergence of CKD of unknown etiology (CKDu) has claimed thousands of lives in several tropical agricultural communities. CKDu is associated with gradual loss of renal function without initial symptoms until reaching complete kidney failure and eventually death. The most impacted are young adult males of lower socio-economic strata. Since the disease progression can be successfully attenuated through early detection, the development of superior screening and management measures is of utmost importance. In contrast to the conventional biomarkers, novel biomarkers with improved sensitivity and specificity are being discussed as promising tools for early diagnosis of the disease. This review summarizes emerging novel biomarkers used in assessing CKD and discusses the current utility and diagnostic potential of such biomarkers for CKDu screening in clinical settings of different communities impacted by CKDu. Our goal is to provide a framework for practitioners in CKDu impacted regions to consider the use of these novel biomarkers through this synthesis. The increased use of these biomarkers will not only help to validate their diagnostic power further and establish potential prognostic value but may also provide critical insights into sites and mechanisms of renal damage.

Purposeful Review to Identify Risk Factors, Epidemiology, Clinical Features, Treatment and Prevention of Chronic Kidney Disease of Unknown Etiology

The global burden of chronic kidney disease (CKD) has risen, and chronic kidney disease of unknown etiology (CKDu) contributes considerably to the national burden of CKD. It is characterized by irreversible, slowly advancing disease, and symptoms often appear in the late stages of the disease. It is a serious, novel cause of kidney failure and leads to premature deaths. Many hypotheses have emerged; however, the etiology of CKDu continues to be elusive and debatable and it is claimed that the etiology is multifactorial, encompassing environmental, genetic, occupational, and social factors. The dominant histopathological feature is chronic tubulointerstitial nephritis. It predominantly affects individuals with low socio-economic status, of working age, largely without chronic comorbidities, who perform strenuous labor in extreme conditions in various tropical areas of the world. It is often fatal due to fast progression and limited access to dialysis or transplant options in the involved geographic areas. Early recognition and appropriate interventions at the earliest possible stage are imperative for decreasing its associated morbidity and mortality. In this review, I tried to summarize available evidence on the risk factors, epidemiology, clinical features, treatment, and prevention of CKDu. The literature search for this review was conducted comprehensively by using different electronic databases and by using appropriate search terms.