Longitudinal Follow-Up of Serum and Urine Biomarkers Indicative of COVID-19-Associated Acute Kidney Injury: Diagnostic and Prognostic Impacts.

In patients hospitalized for severe COVID-19, the incidence of acute kidney injury (AKI) is approximately 40%. To predict and understand the implications of this complication, various blood and urine biomarkers have been proposed, including neutrophil gelatinase-associated lipocalin (NGAL), chemokine (C-C motif) ligand 14 (CCL14), cystatin C, leucine aminopeptidase (LAP), and soluble urokinase plasminogen activator (suPAR). This study, conducted between mid-January and early May 2021, aimed to assess the diagnostic and prognostic capabilities of these biomarkers in a cohort of COVID-19 patients monitored during the initial two weeks of hospitalization. Among the 116 patients included in this study, 48 developed AKI within the first three days of hospitalization (41%), with 29 requiring intensive care unit (ICU) admission, and the overall mortality rate was 18%. AKI patients exhibited a statistically significant increase in urinary LAP levels, indicating acute tubular injury as a potential mechanism underlying COVID-19-related renal damage. Conversely, urinary NGAL and CCL-14 excretion rates did not differ significantly between the AKI and non-AKI groups. Importantly, elevated plasma suPAR and cystatin C levels upon admission persisted throughout the first week of hospitalization and were associated with unfavorable outcomes, such as prolonged ICU stays and increased mortality, irrespective of AKI development. In conclusion, this study underscores the early predictive value of urinary LAP levels in identifying acute tubular injury in COVID-19-induced AKI. Moreover, elevated plasma suPAR and cystatin C levels serve as valuable prognostic markers, offering insights into the short-term morbidity and mortality risks among COVID-19 patients, regardless of AKI occurrence. These findings shed light on the complex interplay between COVID-19, renal injury, and biomarkers with diagnostic and prognostic potential.

Assessment of the Cytotoxicity, Mutagenicity, and Genotoxicity of Two Traditional Chinese Herbs: Aristolochia baetica and Magnolia officinalis.

Herbal remedies used in traditional medicine often contain several compounds combined in order to potentiate their own intrinsic properties. However, herbs can sometimes cause serious health troubles. In Belgium, patients who developed severe aristolochic acid nephropathy ingested slimming pills containing root extracts of an Aristolochia species, as well as the bark of Magnolia officinalis. The goal of the study was to evaluate, on a human renal cell line, Aristolochia and Magnolia extracts for their cytotoxicity by a resazurin cell viability assay, and their genotoxicity by immunodetection and quantification of the phosphorylated histone γ-H2AX. The present study also sought to assess the mutagenicity of these extracts, employing an OECD recognized test, the Ames test, using four Salmonella typhimurium strains with and without a microsomial fraction. Based on our results, it has been demonstrated that the Aristolochia-Magnolia combination (aqueous extracts) was more genotoxic to human kidney cells, and that this combination (aqueous and methanolic extracts) was more cytotoxic to human kidney cells after 24 and 48 h. Interestingly, it has also been shown that the Aristolochia-Magnolia combination (aqueous extracts) was mutagenic with a TA98 Salmonella typhimurium strain in the presence of a microsomial liver S9 fraction. This mutagenic effect appears to be dose-dependent.

Nephroprotective Effects of Two Ganoderma Species Methanolic Extracts in an In Vitro Model of Cisplatin Induced Tubulotoxicity.

Although cisplatin is used as a first-line therapy in many cancers, its nephrotoxicity remains a real problem. Acute kidney injuries induced by cisplatin can cause proximal tubular necrosis, possibly leading to interstitial fibrosis, chronic dysfunction, and finally to a cessation of chemotherapy. There are only a few nephroprotective actions that can help reduce cisplatin nephrotoxicity. This study aims to identify new prophylactic properties with respect to medicinal mushrooms. Among five Ganoderma species, the methanolic extracts of Ganoderma tuberculosum Murill., Ganoderma parvigibbosum Welti & Courtec. (10 µg/mL), and their association (5 + 5 µg/mL) were selected to study respective in vitro effects on human proximal tubular cells (HK-2) intoxicated by cisplatin. Measurements were performed after a pretreatment of 1 h with the extracts before adding cisplatin (20 µM). A viability assay, antioxidant activity, intracytoplasmic ß-catenin, calcium, caspase-3, p53, cytochrome C, IL-6, NFκB, membranous KIM-1, and ROS overproduction were studied. Tests showed that both methanolic extracts and their association prevented a loss of viability, apoptosis, and its signaling pathway. G. parvigibbosum and the association prevented an increase in intracytoplasmic ß-catenin. G. parvigibbosum prevented ROS overproduction and exhibited scavenger activity. None of the extracts could interfere with pro-inflammatory markers or calcium homeostasis. Our in vitro data demonstrate that these mushroom extracts have interesting nephroprotective properties. Finally, the chemical content was investigated through a phytochemical screening, and the determination of the total phenolic and triterpenoid content. Further studies about the chemical composition need to be conducted.

Experimental Aristolochic Acid Nephropathy: A Relevant Model to Study AKI-to-CKD Transition.

Aristolochic acid nephropathy (AAN) is a progressive tubulointerstitial nephritis caused by the intake of aristolochic acids (AA) contained in Chinese herbal remedies or contaminated food. AAN is characterized by tubular atrophy and interstitial fibrosis, characterizing advanced kidney disease. It is established that sustained or recurrent acute kidney injury (AKI) episodes contribute to the progression of CKD. Therefore, the study of underlying mechanisms of AA-induced nephrotoxicity could be useful in understanding the complex AKI-to-CKD transition. We developed a translational approach of AKI-to-CKD transition by reproducing human AAN in rodent models. Indeed, in such models, an early phase of acute tubular necrosis was rapidly followed by a massive interstitial recruitment of activated monocytes/macrophages followed by cytotoxic T lymphocytes, resulting in a transient AKI episode. A later chronic phase was then observed with progressive tubular atrophy related to dedifferentiation and necrosis of tubular epithelial cells. The accumulation of vimentin and αSMA-positive cells expressing TGFß in interstitial areas suggested an increase in resident fibroblasts and their activation into myofibroblasts resulting in collagen deposition and CKD. In addition, we identified 4 major actors in the AKI-to-CKD transition: (1) the tubular epithelial cells, (2) the endothelial cells of the interstitial capillary network, (3) the inflammatory infiltrate, and (4) the myofibroblasts. This review provides the most comprehensive and informative data we were able to collect and examines the pending questions.

Protective Effect of Nebivolol against Oxidative Stress Induced by Aristolochic Acids in Endothelial Cells.

Aristolochic acids (AAs) are powerful nephrotoxins that cause severe tubulointerstitial fibrosis. The biopsy-proven peritubular capillary rarefaction may worsen the progression of renal lesions via tissue hypoxia. As we previously observed the overproduction of reactive oxygen species (ROS) by cultured endothelial cells exposed to AA, we here investigated in vitro AA-induced metabolic changes by 1H-NMR spectroscopy on intracellular medium and cell extracts. We also tested the effects of nebivolol (NEB), a ß-blocker agent exhibiting antioxidant properties. After 24 h of AA exposure, significantly reduced cell viability and intracellular ROS overproduction were observed in EAhy926 cells; both effects were counteracted by NEB pretreatment. After 48 h of exposure to AA, the most prominent metabolite changes were significant decreases in arginine, glutamate, glutamine and glutathione levels, along with a significant increase in the aspartate, glycerophosphocholine and UDP-N-acetylglucosamine contents. NEB pretreatment slightly inhibited the changes in glutathione and glycerophosphocholine. In the supernatants from exposed cells, a decrease in lactate and glutamate levels, together with an increase in glucose concentration, was found. The AA-induced reduction in glutamate was significantly inhibited by NEB. These findings confirm the involvement of oxidative stress in AA toxicity for endothelial cells and the potential benefit of NEB in preventing endothelial injury.

Characterization of cytotoxic effects of aristolochic acids on the vascular endothelium.

Aristolochic acid nephropathy (AAN) is characterized by interstitial fibrosis, proximal tubular atrophy, and hypoxia. A correlation between a reduced peritubular capillary density and the severity of fibrosis has been demonstrated. As calcium, redox and energetic homeostasis are crucial in maintaining endothelial cell function and survival, we aimed to investigate AA-induced disturbances involved in endothelial cell injury. Our results showed a cytotoxic effect of AA on EAhy926 endothelial cells. Exposure of aortic rings to AA impaired vascular relaxation to Acetylcholine (ACh). Increased levels of intracellular reactive oxygen species (ROS) were observed in cells exposed to AA. Pre-treatment with antioxidant N-acetyl cysteine inhibited AA-induced cell death. Superoxide dismutase resulted in restoring ACh-induced relaxation. An increase in intracellular calcium level ([Ca2+]i) was observed on endothelial cells. Calcium chelators BAPTA-AM or APB, a specific inhibitor of IP3R, improved cell viability. Moreover, AA exposure led to reduced AMP-activated protein kinase (AMPK) expression. AICAR, an activator of AMPK, improved the viability of AA-intoxicated cells and inhibited the rise of cytosolic [Ca2+]i levels. This study provides evidence that AA exposure increases ROS generation, disrupts calcium homeostasis and decreases AMPK activity. It also suggests that significant damage observed in endothelial cells may enhance microcirculation defects, worsening hypoxia and tubulointerstitial lesions.

The impact of p53 on aristolochic acid I-induced nephrotoxicity and DNA damage in vivo and in vitro.

Exposure to aristolochic acid (AA) is associated with human nephropathy and urothelial cancer. The tumour suppressor TP53 is a critical gene in carcinogenesis and frequently mutated in AA-induced urothelial tumours. We investigated the impact of p53 on AAI-induced nephrotoxicity and DNA damage in vivo by treating Trp53(+/+), Trp53(+/-) and Trp53(-/-) mice with 3.5 mg/kg body weight (bw) AAI daily for 2 or 6 days. Renal histopathology showed a gradient of intensity in proximal tubular injury from Trp53(+/+) to Trp53(-/-) mice, especially after 6 days. The observed renal injury was supported by nuclear magnetic resonance (NMR)-based metabonomic measurements, where a consistent Trp53 genotype-dependent trend was observed for urinary metabolites that indicate aminoaciduria (i.e. alanine), lactic aciduria (i.e. lactate) and glycosuria (i.e. glucose). However, Trp53 genotype had no impact on AAI-DNA adduct levels, as measured by 32P-postlabelling, in either target (kidney and bladder) or non-target (liver) tissues, indicating that the underlying mechanisms of p53-related AAI-induced nephrotoxicity cannot be explained by differences in AAI genotoxicity. Performing gas chromatography-mass spectrometry (GC-MS) on kidney tissues showed metabolic pathways affected by AAI treatment, but again Trp53 status did not clearly impact on such metabolic profiles. We also cultured primary mouse embryonic fibroblasts (MEFs) derived from Trp53(+/+), Trp53(+/-) and Trp53(-/-) mice and exposed them to AAI in vitro (50 µM for up to 48 h). We found that Trp53 genotype impacted on the expression of NAD(P)H:quinone oxidoreductase (Nqo1), a key enzyme involved in AAI bioactivation. Nqo1 induction was highest in Trp53(+/+) MEFs and lowest in Trp53(-/-) MEFs; and it correlated with AAI-DNA adduct formation, with lowest adduct levels being observed in AAI-exposed Trp53(-/-) MEFs. Overall, our results clearly demonstrate that p53 status impacts on AAI-induced renal injury, but the underlying mechanism(s) involved remain to be further explored. Despite the impact of p53 on AAI bioactivation and DNA damage in vitro, such effects were not observed in vivo.

CD4+ and CD8+ T Cells Exert Regulatory Properties During Experimental Acute Aristolochic Acid Nephropathy.

Experimental aristolochic acid nephropathy is characterized by transient acute proximal tubule necrosis and inflammatory cell infiltrates followed by interstitial fibrosis and tubular atrophy. The respective role of T-cell subpopulations has never been studied in the acute phase of the mouse model, and was heretofore exclusively investigated by the use of several depletion protocols. As compared to mice injected with aristolochic acids alone, more severe acute kidney injury was observed after CD4+ or CD8+ T-cells depletion. TNF-alpha and MCP-1 mRNA renal expressions were also increased. In contrast, regulatory T-cells depletion did not modify the severity of the aristolochic acids induced acute kidney injury, suggesting an independent mechanism. Aristolochic acids nephropathy was also associated with an increased proportion of myeloid CD11bhighF4/80mid and a decreased proportion of their counterpart CD11blowF4/80high population. After CD4+ T-cell depletion the increase in the CD11bhighF4/80mid population was even higher whereas the decrease in the CD11blowF4/80high population was more marked after CD8+ T cells depletion. Our results suggest that CD4+ and CD8+ T-cells provide protection against AA-induced acute tubular necrosis. Interestingly, T-cell depletion was associated with an imbalance of the CD11bhighF4/80mid and CD11blowF4/80high populations.

Early detection of acute cisplatin nephrotoxicity: interest of urinary monitoring of proximal tubular biomarkers.

BACKGROUND: Renal toxicity induced by cisplatin (CisPt) is a clinical issue in patients with or without chronic kidney disease (CKD). Proximal tubular injury can result in acute kidney injury (AKI), which may compromise the course of chemotherapy and the prognosis. The purpose of this study was to investigate the time course of urinary markers of acute tubulotoxicity and to assess the usefulness of such monitoring in a routine clinical setting. METHODS: This work is an open prospective pilot study carried out among 23 patients receiving a platinum-based chemotherapy. Individual comorbidities, plasma parameters of kidney function (urea, creatinine) and estimated glomerular filtration rate were registered. Urinary excretion of leucine aminopeptidase, neutrophil gelatinase-associated lipocalin, cystatin C, liver fatty acid-binding protein and interleukin-18 were monitored during successive chemotherapy cycles. Episodes of AKI were identified according to KDIGO (Kidney Disease Improving Global Outcomes) 2012 guidelines. RESULTS: A total of 28 patients were recruited; among them 23 agreed to be part of the study, of whom 18 received CisPt and 5 carbo- or oxaliplatin. Of the 18 CisPt patients, 12 had a preexisting CKD. Sixteen AKI episodes were observed in 13 patients receiving CisPt with a pejorative evolution in seven cases (partial recovery of the renal function); a transient but dramatic increase in urinary biomarkers was observed 3 h after chemotherapy initiation, whereas plasma creatinine rise appeared 72 h after the end of CisPt treatment. Identified precipitating factors included: dehydration due to lack of fluid intake or diuretic use, exposure to high CisPt doses, regular use of nonsteroidal anti-inflammatory drugs and/or iodinated contrast agents and sepsis. CONCLUSION: Even if numerous precipitating factors could be avoided, the monitoring of urinary markers seemed helpful for the early detection of subclinical AKI induced during CisPt chemotherapy.

Protective Effects of Pistacia lentiscus L. fruit extract against calcium oxalate monohydrate induced proximal tubular injury.

ETHNOPHARMACOLOGICAL RELEVANCE: The world prevalence of kidney stones is increasing and plants are frequently used to treat urolithiasis. Pistacia lentiscus L, a plant which freely grows around the Mediterranean basin areas, is widely used for various pathologies. P. lentiscus has an important impact as it has economical value on top of its pharmacological interest. Decoctions of its aerial parts and/or resin are used to treat kidney stones. AIM OF THE STUDY: To in vitro assess the potential nephroprotective effect of Pistacia lentiscus ethanolic fruit extract (PLEF) on proximal tubular cells in response to the adhesion of calcium oxalate monohydrate (COM) crystals. MATERIALS AND METHODS: Human Kidney [HK]-2 cells were incubated with and without COM in the presence or absence of PLEF. Cell viability was measured by the resazurin assay. The expression of E-cadherin was analyzed by PCR. The extracellular production of H2O2 was measured by Amplex® Red H2O2 Assay. The numbers of detached or non-adherent COM crystals in the presence of PLEF were microscopically captured and counted using ImageJ software. The interaction of PLEF with COM and the effect of PLEF on crystal size were analyzed by flow cytometry. The spectrophotometric measurement of turbidity was performed for assessing the COM concentration. RESULTS: PLEF incubated with COM was able to increase the cell viability. The decrease of E-cadherin expression after incubation with COM was counteracted by PLEF. Overproduction of H2O2 induced by COM was also inhibited by PLEF. Observations using flow cytometry showed that interactions between PLEF and the COM crystals occurred. PLEF was also effective in reducing the particles size and in lowering COM concentration. CONCLUSION: Our data show that COM tubulotoxicity can be significantly reversed by PLEF -at least in part- via an inhibition of COM crystals adhesion onto the apical membrane. This early beneficial effect of PLEF needs to be further investigated as a useful strategy in nephrolithiasis prevention.

Extrachromosomal HPV-16 LCR transcriptional activation by HDACi opposed by cellular differentiation and DNA integration.

Histone deacetylase inhibitors (HDACi) have been shown to render HPV-carrying cells susceptible to intrinsic and extrinsic apoptotic signals. As such, these epigenetic drugs have entered clinical trials in the effort to treat cervical cancer. Here, we studied the effect of common HDACi, with an emphasis on Trichostatin A (TSA), on the transcriptional activity of the HPV-16 Long Control Region (LCR) in order to better understand the impact of these agents in the context of the HPV life cycle and infection. HDACi strongly induced transcription of the firefly luciferase reporter gene under the control of the HPV-16 LCR in a variety of cell lines. In the HaCaT keratinocyte cell line undergoing differentiation induced by TSA, we observed a reduction in LCR-controlled transcription. Three major AP-1 binding sites in the HPV-16 LCR are involved in the regulation by TSA. However, whatever the status of differentiation of the HaCaT cells, TSA induced integration of extra-chromosomal transfected DNA into the cellular genome. Although these data suggest caution using HDACi in the treatment of HR HPV infection, further in vivo studies are necessary to better assess the risk.

Blocking TGF-ß Signaling Pathway Preserves Mitochondrial Proteostasis and Reduces Early Activation of PDGFRß+ Pericytes in Aristolochic Acid Induced Acute Kidney Injury in Wistar Male Rats.

BACKGROUND: The platelet-derived growth factor receptor ß (PDGFRß)+ perivascular cell activation becomes increasingly recognized as a main source of scar-associated kidney myofibroblasts and recently emerged as a new cellular therapeutic target. AIMS: In this regard, we first confirmed the presence of PDGFRß+ perivascular cells in a human case of end-stage aristolochic acid nephropathy (AAN) and thereafter we focused on the early fibrosis events of transforming growth factor ß (TGFß) inhibition in a rat model of AAN. MATERIALS AND METHODS: Neutralizing anti-TGFß antibody (1D11) and its control isotype (13C4) were administered (5 mg/kg, i.p.) at Days -1, 0, 2 and 4; AA (15 mg/kg, sc) was injected daily. RESULTS: At Day 5, 1D11 significantly suppressed p-Smad2/3 signaling pathway improving renal function impairment, reduced the score of acute tubular necrosis, peritubular capillaritis, interstitial inflammation and neoangiogenesis. 1D11 markedly decreased interstitial edema, disruption of tubular basement membrane loss of brush border, cytoplasmic edema and organelle ultrastructure alterations (mitochondrial disruption and endoplasmic reticulum edema) in proximal tubular epithelial cells. Moreover, 1D11 significantly inhibited p-PERK activation and attenuated dysregulation of unfolded protein response (UPR) pathways, endoplasmic reticulum and mitochondrial proteostasis in vivo and in vitro. CONCLUSIONS: The early inhibition of p-Smad2/3 signaling pathway improved acute renal function impairment, partially prevented epithelial-endothelial axis activation by maintaining PTEC proteostasis and reduced early PDGFRß+ pericytes-derived myofibroblasts accumulation.

New in vitro insights on a cell death pathway induced by magnolol and honokiol in aristolochic acid tubulotoxicity.

Aristolochic acids (AA) are nephrotoxic agents found in Aristolochia species whose consumption leads to the onset of a progressive tubulointerstitial fibrosis. This AA-nephropathy was first reported during the Belgian outbreak of the 1990's in which more than a hundred patients consumed slimming pills containing an Aristolochia species and Magnolia officinalis. The patients developed an end-stage kidney disease requiring dialysis or transplantation. Magnolol and honokiol are bioactive compounds from M. officinalis known for their potent antioxidant activity. As they can alleviate oxidative stress, we investigated their respective effects on AA-mediated tubulotoxicity using HK-2 cells. Magnolol and honokiol were able to reduce the oxidative stress associated with AA-treatment. Cytotoxicity alleviation was further investigated and overall cell viability measurements unexpectedly revealed that both compounds worsened the survival of AA-treated cells. Flow cytometry analyses of annexin V/PI stained cells indicated that the lignans efficiently prevented AA-induced apoptosis; but favored necrosis. Microscopy observations highlighted extensive vacuolization; other types of cell death, including autophagy, paraptosis or accelerated senescence were excluded. Ki-67 index and cell cycle analysis indicated that both magnolol and honokiol inhibited proliferation by blocking the cell cycle at the G1 phase; they also prevented the AA-induced G2/M arrest.

In vitro effects of Panax ginseng in aristolochic acid-mediated renal tubulotoxicity: apoptosis versus regeneration.

This in vitro study aimed to determine the effects of a Panax ginseng extract on aristolochic acid-mediated toxicity in HK-2 cells. A methanolic extract of ginseng (50 µg/mL) was able to reduce cell survival after treatment with 50 µM aristolochic acid for 24, 48, and 72 h, as evidenced by a resazurin reduction assay. This result was confirmed by a flow cytometric evaluation of apoptosis using annexin V-PI staining, and indicated higher apoptosis rates in cells treated with aristolochic acid and P. ginseng extract compared with aristolochic acid alone. However, P. ginseng extract by itself (5 and 50 µg/mL) increased the Ki-67 index, indicating an enhancement in cellular proliferation. Cell cycle analysis excluded a P. ginseng extract-mediated induction of G2/M cell cycle arrest such as the one typically observed with aristolochic acid. Finally, ß-catenin acquisition was found to be accelerated when cells were treated with both doses of ginseng, suggesting that the epithelial phenotype of renal proximal tubular epithelial cells was maintained. Also, ginseng treatment (5 and 50 µg/mL) reduced the oxidative stress activity induced by aristolochic acid after 24 and 48 h. These results indicate that the ginseng extract has a protective activity towards the generation of cytotoxic reactive oxygen species induced by aristolochic acid. However, the ginseng-mediated alleviation of oxidative stress did not correlate with a decrease but rather with an increase in aristolochic acid-induced apoptosis and death. This deleterious herb-herb interaction could worsen aristolochic acid tubulotoxicity and reinforce the severity and duration of the injury. Nevertheless, increased cellular proliferation and migration, along with the improvement in the epithelial phenotype maintenance, indicate that ginseng could be useful for improving tubular regeneration and the recovery following drug-induced kidney injury. Such dual activities of ginseng certainly warrant further in vivo studies.

Substitution between Aristolochia and Bryonia genus in North-Eastern Morocco: toxicological implications.

ETHNOPHARMACOLOGICAL RELEVANCE: Although acknowledged as toxic herbs, Aristolochia species are still widely used worldwide. The aristolochic acids (AA) they contain can induce the so-called "aristolochic acid nephropathy", leading to renal fibrosis and upper urinary tract cancer. Traditional Moroccan medicine still often uses Aristolochia species under the vernacular name of Bereztem for the treatment of numerous ailments, notably cancer, diabetes or digestive tract disorders. As the botanical identity and renal toxicity of used species remain unexplored, the safety of patients may be threatened. MATERIAL AND METHODS: Ethnopharmacological data were collected from herbalists from the provinces of Oujda and Berkane, located in North-Eastern Morocco. Samples of Bereztem were collected at herbalist shops and checked for their content in AA using TLC and LC-MS methods. The toxicity of crude methanolic extracts of each herb was assessed on a HK-2 cell-based in vitro model by measurement of the cell survival to evaluate cytotoxicity and by assessment of renal-specific toxicity via (i) the evaluation of genes (E-cadherin and α-smooth muscle actin) expression by RT-qPCR; (ii) the quantities of ß-catenin and vimentin by immunofluorescence microscopy; (iii) the secretion of fibronectin; and (iv) the excretion of interleukin-6. RESULTS: The survey indicated that, among 42 herbalists visited, 33 were retailers of Bereztem, which was generally sold as a cancer treatment. Botanical investigations revealed that Aristolochia longa was frequently substituted by Bryonia dioica, which was associated with a higher cytotoxicity. Parameters specific to renal toxicity were also found to be enhanced, as compared to Aristolochia baetica and A. longa: down-regulation of ß-catenin and E-cadherin and up-regulation of vimentin and α-smooth muscle actin, and secretion of fibronectin and interleukin-6. CONCLUSION: In accordance with the Moroccan regulations, the use of so-called Aristolochia species should be discontinued. On one hand, the correctly identified aristolochia contain nephrotoxic aristolochic acids; on the other hand, aristolochia are massively substituted in North-Eastern Morocco and adulterated by a well-known toxic herb, B. dioica. Our data indicate that the bryony renal toxicity may be deleterious in shorter time periods than aristolochia. Reinforced on-site controls are needed to remind herbalists and harvesters that these herbs should be prohibited.

Human bone morphogenetic protein-7 does not counteract aristolochic acid-induced renal toxicity.

Aristolochic acids (AA) are nephrotoxic and profibrotic agents, leading to chronic kidney disease. As some controversial studies have reported a nephroprotective effect of exogenous recombinant human bone morphogenetic protein (rhBMP)-7 in several models of renal fibrosis, we investigated the putative effect of rhBMP-7 to prevent progressive tubulointerstitial damage after AA intoxication in vitro and in vivo. In vitro, the toxicity of AA on renal tubular cells was demonstrated by an increase in vimentin as well as a decrease in ß-catenin expressions, reflecting a dedifferentiation process. Increased fibronectin and interleukin-6 levels were measured in the supernatants. Enhanced α-SMA mRNA levels associated to decreased E-cadherin mRNA levels were also measured. Incubation with rhBMP-7 only prevented the increase in vimentin and the decrease in ß-catenin expressions. In vivo, in a rat model of AA nephropathy, severe tubulointerstitial lesions induced by AA after 10 and 35 days (collagen IV deposition and tubular atrophy), were not prevented by the rhBMP-7 treatment. Similarly, rhBMP-7 did not ameliorate the significant increase in urinary concentrations of transforming growth factor-ß. In summary, our in vitro data demonstrated a poor beneficial effect of rhBMP-7 to reverse cell toxicity while, in vivo, there was no beneficial effect of rhBMP-7. Therefore, further investigations are needed to confirm the exact role of BMP-7 in progressive chronic kidney disease.

Nephroprotective effects of ferulic acid, Z-ligustilide and E-ligustilide isolated from Angelica sinensis against cisplatin toxicity in vitro.

Cisplatin (CisPt), a chemotherapeutic drug applied against solid tumors, is highly detrimental to the kidney. The risk of acute kidney injury implies adequate patient hydration to ensure sufficient diuresis; this strategy, now implemented in clinical practice, remains however incompletely satisfactory. New pharmacological approaches relying on the discovery of bioactive compounds need to be developed. Based on previous studies reporting renoprotective activities for extracts of Angelica sinensis (Oliv.) Diels roots, three of its major active compounds, ferulic acid, Z-ligustilide and E-ligustilide, were investigated for possible alleviation of CisPt-induced nephrotoxicity. Five phenomena involved in acute kidney injury and subsequent fibrosis were investigated: (i) modulation of cell survival via reduction of the apoptosis rate; (ii) reduction of oxidative stress; (iii) improvement of tubular regeneration capacities through proliferation and migration; (iv) limitation of extracellular matrix and collagen deposition; and (v) prevention of the dedifferentiation processes via the ß-catenin pathway. Ferulic acid emerged as the most potent compound for alleviating cell death and collagen deposition, and for enhancing cell regeneration capacities. It also partially inhibited the ß-catenin pathway, but was ineffective in lowering oxidative stress. Z- and E-ligustilides, however, were effective for limiting the oxidative stress, but only moderately affected other parameters. Ferulic acid appears to be a promising nephroprotective drug lead deserving further preclinical investigation.

Potential nephroprotective effects of the Chinese herb Angelica sinensis against cisplatin tubulotoxicity.

CONTEXT: Acute kidney injury (AKI) is often encountered in patients receiving cisplatin (CisPt), a chemotherapeutic drug that induces numerous toxic side effects. Techniques used to limit nephrotoxicity during CisPt treatment are not fully effective; about a third of patients experience AKI. New nephroprotective strategies, including pharmacological approaches, must be developed. OBJECTIVE: The present study investigated the nephroprotective potential of Angelica sinensis (Oliv.) Diels (Apiaceae) root towards CisPt tubulotoxicity. MATERIALS AND METHODS: HK-2 cells were incubated with CisPt (10 µM) and/or with a methanolic extract of A. sinensis (AS). Nephroprotective capacity was evaluated by means of cellular viability (resazurin assay) and apoptosis (annexin-V/PI staining), oxidative stress generation (H2DCF-DA oxidation), Ki-67 index (immunofluorescence), cell cycle analysis (DNA staining), cell migration rate (scratch assay), extracellular matrix deposition (collagen determination), and ß-catenin relocalization. RESULTS: CisPt decreased cell viability [76% versus Ctrl], which was associated with an increased apoptosis. Simultaneous treatment with 50 µg/ml AS enhanced cell survival [84% versus Ctrl] and decreased the apoptosis rate. AS could not alleviate CisPt-induced oxidative stress; but doses of 5 and 50 µg/ml raised the Ki-67 index [135 and 244% versus Ctrl] and cell migration rates [1.2 and 1.3-fold versus Ctrl]. Finally, both doses of AS limited the amount of collagen deposition [121.6 and 119.6% for 5 and 50 µg/ml, respectively, versus 131.0% for CisPt-treated cells] and prevented the relocalization of ß-catenin from the membrane to the nucleus. CONCLUSION: These results confirm the nephroprotective potential of A. sinensis and require further investigations aiming at identifying its active compounds.

Evaluation of diagnostic criteria for endemic nephropathy.

Diagnosis of endemic nephropathy (EN) is based on the combination of several clinical and laboratory criteria. Despite extensive research no specific diagnostic biomarker for EN has yet been identified. The aim of the study was to evaluate the diagnostic significance of the variables previously proposed as diagnostic criteria, but also new ones. After an extended questionnaire, the clinical and laboratory examination population in EN villages was classified according to the modified WHO criteria. The urinary active form of TGF-ß was measured with a bioassay using a cell line which expresses luciferase activity. In the study we used ROC analysis to examine the predictive value of the tested variables. In the study there was no difference in haemoglobin level between the study subgroups. Leucine aminopeptidase (LAP) in urine and active urinary TGF-ß levels were increased in the EN diseased group when compared to other subgroups, but they did not fulfil the statistical criteria needed for differentiating a diseased form from other study subgroups. Both kidney length and parenchima thickness, alfa1-microglobulinuria, and kidney function assessed by MDRD formula were the variables that differentiated the study subgroups well. Based on our results the cut-off value of alfa1-microglobulin for screening should be 23.5 mg/g creatinine instead of 15 mg/g creatinine in the present criteria, and for making a diagnosis of EN 31,5 mg/g creatinine. Persons with a positive family history for EN had a 5.8 times greater risk of developing EN when compared to a negative one. Taken together, the above-mentioned variables should be implemented in new uniform diagnostic criteria for EN.

Protective effects of schizandrin and schizandrin B towards cisplatin nephrotoxicity in vitro.

Renal proximal tubular epithelial cells are the main targets of toxic drugs such as cisplatin (CisPt), an alkylating agent indicated for the treatment of solid organ tumors. Current techniques aiming at reducing nephrotoxicity in patients receiving CisPt are still not satisfactory as they can only partially prevent acute kidney injury. New nephroprotective strategies remain to be developed. In the present in vitro study, schizandrin (Schi) and schizandrin B (Schi B), major phytochemicals from Schisandra chinensis (Turcz.) Baill. fruits, were tested on HK-2 cells along four processes that could help alleviate CisPt toxicity. Results indicated that: (i) both Schi and Schi B enhanced cell survival via reducing apoptosis rate; (ii) only Schi showed moderate effects towards modulation of regeneration capacities of healthy cells; (iii) both Schi and Schi B limited extracellular matrix deposition; and (iv) both compounds could help preventing dedifferentiation processes via the ß-catenin pathway. Schi and Schi B present promising activities for future development of protective agents against CisPt nephrotoxicity.