Rapidly progressive interstitial renal fibrosis associated with Chinese herbal medications

Molecular Characterization of Microrna Interference and Aristolochic Acid Intoxication Found in Upper Tract Urothelial Carcinoma in Patients with Balkan Endemic Nephropathy: A Systematic Review of the Current Literature

The term "aristolochic acid nephropathy" (AAN) is used to include any form of toxic interstitial nephropathy that is caused either by ingestion of plants containing aristolochic acids (AA) or by the environmental contaminants in food such as in Balkan endemic nephropathy (BEN). Aristolochic acid (AA) intoxication is strongly associated with the development of upper tract urothelial carcinoma (UTUC); however, the underlying molecular mechanism remains to be defined. MicroRNAs (miRNA) regulate several biological processes, including cell proliferation, differentiation, and metabolism, acting as oncogenes or tumor suppressors. A unique miRNA expression profile suggested that miRNAs could function as regulators in UTUC developmental processes. This review aimed to summarize data available in the literature about underlying molecular mechanisms leading to the expression of miRNAs in AA-UTUC patients with BEN. Strong correlation in AA-UTUC has a distinctive gene alteration pattern, AL-DNA adducts, and a unique tumor protein (TP53) mutational spectrum AAG to TAG (A: T→T: A) transversion in codon 139 (Lys → Stop) of exon 5 activates the p53 tumor suppressor protein. Further, p53 protein is responsible not only for the expression of miRNAs but also acts as a target molecule for miRNAs and plays a crucial function in the AA-UTUC pathogenicity through activation of cyclin-dependent kinase (CyclinD1) and cyclin protein kinase 6(CDK6) to support cell cycle arrest. This study, proposed a molecular mechanism that represented a possible unique relationship between AA intoxication, miRNAs expression, and the progression of UTUC in patients with BEN.

Use of Medicinal Plants in Africa: A Case Study From the Democratic Republic of Congo (DRC)

Although medicinal plants are beneficial, they also can be important risk factors for the development of acute and chronic kidney injury, as well toxicity of other solid organs. There are a lack of reports of adverse kidney events and drug interactions resulting from medicinal plants owing to a lack of professional surveillance and specific data on kidney toxicity, especially in low-resource settings. Within the context of increased medicinal plant use and lack of effective regulatory control, safety is a key priority issue. We review the benefits and adverse effects of medicinal plants with particular reference to nephrotoxicity encountered in the Democratic Republic of Congo in sub-Saharan Africa.

Aristolochic acid-containing Chinese herbal medicine and upper urinary tract urothelial carcinoma in Taiwan: a narrative review

PURPOSE

The high incidence of upper urinary tract urothelial carcinoma (UTUC) in Taiwan is largely due to exposure to aristolochic acid (AA), a principal component of Aristolochia-based herbal medicines. Here we systematically review the molecular epidemiology, clinical presentation and biomarkers associated with AA-induced UTUC.

METHODS

This is a narrative review. Medline, Embase, and Web of Science were searched from inception to December 31, 2021. Studies evaluating the association, detection, and clinical characteristics of AA and UTUC were included.

RESULTS

A nationwide database revealed 39% of the Taiwanese population had been exposed to AA-containing herbs between 1997 and 2003. Epidemiological reports revealed AA posed a significantly higher hazard for renal failure and UTUC in herbalists and the general population who ingested AA-containing herbs. The presence of aristolactam-DNA adducts and a distinctive signature mutation, A:T to T:A transversions, located predominantly on the non-transcribed DNA strand, with a strong preference for deoxyadenosine in a consensus sequence (CAG), was observed in many UTUC patients. Clinically, AA-related UTUC patients were characterized by a younger age, female gender, impaired renal function and recurrence of contralateral UTUC. To date, there are no preventive measures, except prophylactic nephrectomy, for subjects at risk of AA nephropathy or AA-related UTUC.

CONCLUSION

AA exposure via Aristolochia-based herbal medicines is a problem throughout Taiwan, resulting in a high incidence of UTUC. Aristolactam-DNA adducts and a distinctive signature mutation, A:T to T:A transversions, can be used as biomarkers to identify AA-related UTUC. AA-related UTUC is associated with a high recurrence rate of contralateral UTUC.

Frequency and etiology of tubulo-interstitial nephritis in an adult renal biopsies in a tertiary renal care hospital: A single-center study

Tubulo-interstitial nephritis (TIN) is an important cause of acute renal failure which may progresses to chronic kidney disease (CKD). TIN is often under diagnosed with there are no specific signs and symptoms. As this entity has paramount importance, so we evaluated the frequency and etiological of TIN both acute TIN (ATIN) and chronic tububulo-interstitial nephritis (CTIN) in renal biopsies. This is a retrospective observational, descriptive study carried out in the Department of Nephrology at The Kidney Centre Post Graduate Training Institute from 2004 to 2016. A total of 1560 adult renal biopsies were done during this period with 125 biopsies of TIN, of which 70 (56%) cases were ATIN and 55 (44%), were CTIN. Thirty-eight (30%) patients had a history of taking proton-pump inhibitors, use of various antibiotics in 21 (16%) cases, and 11 (8%) patients had a history of taking Hakeemi (traditional healer using herbs and sometimes trace amounts of heavy metals) medications. The incidence of TIN is higher than suspected and can be caused by variety of etiological agents. Therefore, clinical awareness will help in the diagnosis and early identification of the disease.

Ginsenoside Rb1 ameliorates autophagy via the AMPK/mTOR pathway in renal tubular epithelial cells in vitro and in vivo

Although ginsenoside Rb1 (G-Rb1) has exerted an inhibitory effect on renal fibrosis and progression of chronic kidney disease (CKD), its mechanism remains unknown. This study aims to explore the anti-fibrosis effect of G-Rb1 in unilateral ureter obstruction (UUO) mouse model and underlying mechanisms in HBSS-induced HK-2 cells. In vivo, renal function, kidney histological pathology, and autophagy-related protein molecules were assessed. Additionally, rapamycin, Deptor overexpression plasmid, Akt inhibitor, metformin, and a p38-MAPK inhibitor, as well as an ERK-MAPK inhibitor were used to evaluate the effect of AMPK/mTOR, Akt and MAPK signal pathways on the protective effect of G-Rb1 in HK-2 cells. Treatment with G-Rb1 significantly improved renal dysfunction. G-Rb1 reversed UUO-induced downregulation of p62, and upregulation of LC3 and the ratio of LC3 I/II, indicating that G-Rb1 restrained UUO-induced activation of autophagy. Furthermore, we found that treatment of HBSS-induced HK-2 cells with G-Rb1 resulted in AMPK/mTOR and ERK, p38 MAPKs signaling pathways regulated autophagy inhibition. These findings may explain, in part, the molecular mechanisms by which G-Rb1 could be applied in the treatment of patients with CKD, further suggesting that autophagy and its associated molecular signaling pathway may be new targets for the treatment of renal fibrosis and CKD.

An Overview on Analytical Methods for Quantitative Determination of Aristolochic Acids

Background:

Aristolochic acids are chemically linked to nitrophenanthrene carboxylic acids which are found in aristolochia plants. These compounds are intrinsically carcinogenic, while they have been used in traditional medicine from a long time ago. Despite the beneficial effects of herbals for treating some diseases, they possess some side effects.

Methods:

Therefore, the development of a sensitive and selective procedure for the determination of these harmful components in various complicated samples is an important task for health systems and drug authorities. In the past years, ultra-pressure liquid chromatography, high performance liquid chromatography and capillary electrophoresis with different detection systems were used for determination of aristolochic acids in various samples.

Results:

In this review, different analytical methods have been discussed in brief and applications of them in diverse samples have been summarized.

Conclusion:

Different approaches are compared from point of sensitivity, selectivity, and extraction efficiency.

[Evaluation of renal oxygenation in rats with acute aristolochic acid nephropathy using blood oxygenation level-dependent magnetic resonance imaging]

OBJECTIVE

To evaluate the changes in renal oxygenation in rats with acute aristolochic acid nephropathy using blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) at 7.0T.

METHODS

Wistar rats were randomly divided into AAN group (n=18) and control group (n=6) for intraperitoneal injections of AAI at 40 mg/kg and PEG400, respectively, on a daily basis for 6 consecutive days. All the control rats and 6 rats from AAN group underwent BOLD MRI scan before and at 2, 4, and 6 days after the initial injection for measuring renal cortical and medullary R2^* values. At each of the 4 time points, 3 rats in AAN group were sacrificed for histological evaluation; the control rats were examined at 6 days after the initial injection.

RESULTS

The cortical and medullary R2^* values of the rats in AAN group on days 4 and 6 were significantly higher than those in the control group (P < 0.05). In AAN group, the cortical R2^* values showed no obvious changes on day 2 as compared with the baseline values, but increased significantly on day 4 (P < 0.05) and day 6 (P < 0.01); the medullary R2^* values increased progressively and were significantly higher than the baseline values on day 4 (P < 0.01) and day 6 (P < 0.01). In the control group, no significant changes were detected in either cortical or medullary R2^* values throughout the experiment.

CONCLUSIONS

BOLD MRI allows non-invasive measurement of renal oxygenation levels in rats with AAN. The increase of renal cortical and medullary R2^* values, and particularly the latter, indicates a lowered renal oxygenation level, which provides potentially useful information for clinical decisions.

Kidney toxicity related to herbs and dietary supplements: Online table of case reports. Part 3 of 5 series

BACKGROUND

No tabular summary of potentially life-threatening, kidney-toxic dietary supplements (DS; includes herbs) based on PubMed case reports is currently available online and continually updated to forewarn United States consumers, clinicians, and companies manufacturing DS. The purpose of this review was to create an online research summary table of kidney toxicity case reports related to DS.

METHODS

Documented PubMed case reports (1966 to May 2016, and cross-referencing) of DS appearing to contribute to kidney toxicity were listed in "DS Toxic Tables." Keywords included "herb" or "dietary supplement" combined with "kidney" to generate an overview list, and possibly "toxicity" to narrow the selection. Case reports were excluded if they involved herb combinations (some exceptions), Chinese herb mixtures, teas of mixed herb contents, mushrooms, poisonous plants, self-harm, excessive doses (except vitamins/minerals), legal or illegal drugs, drug-herbal interactions, and confounders of drugs or diseases. Since commercial DS often include a combination of ingredients, they were treated separately; so were foods. A few foods with kidney-toxic effects were listed in a fourth table. The spectrum of herbal or DS-induced kidney injuries included kidney stones, nephritis, nephrotic syndrome, necrosis, acute kidney injury (AKI; previously known as acute renal failure [ARF]), chronic kidney disease, kidney transplant, and death.

RESULTS

Approximately 7 herbs (minus 4 no longer for sale) and 10 dietary supplements (minus 3 excluded due to excessive doses + germanium that is no longer sold) have been related to kidney injury case reports published in PubMed (+crosslisting) in the last 50 + years (1966 to May 2016). The implicated herbs include Chinese yew (Taxus celbica) extract, impila (Callilepis laureola), morning cypress (Cupressus funebris Endl), St. John's wort (Hypericum perforatum), thundergod vine (Tripterygium wilfordii hook F), tribulus (Tribulus terrestris) and wormwood (Artemisia herba-alba). No longer sold in the United States are chocolate vine or mu tong (Caulis aristolochiae), guang fang ji (Aristolochia fangchi), ma huang (Ephedra sinica), and Tenshin Tokishigyaku-ka-goshuyu-shokyo-to. The DS include bile (sheep), chlorella, chromium (Cr), CKLS, creatine, gallbladder (fish), glucosamine, hydrazine, N.O.-Xplode, Spanish fly, and excess intakes of vitamins A, C, and D. Germanium (Ge) is not available for sale. The top two DS with the largest number of reported publications, but not always case reports, in descending order, were the aristolochic acid-containing herbs guang fang ji (mistaken identity) and chocolate vine or mu tong. The remaining DS featured one to three publications over a 50+ year period. Numerous case reports were reported for kidney-toxic foods: djenkol bean, gallbladders (carp fish, pufferfish, & snake), and star fruit (only in chronic kidney disease patients), and uncooked yam powder or juice.

CONCLUSION

This online "DS Toxic Table" provides clinicians, consumers, and manufacturers with a list of herbs that could potentially contribute to kidney injuries.

The potential role of aquaporin 1 on aristolochic acid I induced epithelial mesenchymal transition on HK-2 cells

Aristolochic acid I (AA-I), one of the main active components in Aristolochaia herbs, may induce aristolochic acid nephropathy (AAN). Renal interstitial fibrosis is one of the most typical features of AAN. To investigate the mechanism of Aristolochic acid I (AA-I) -induced renal epithelial-mesenchymal transition (EMT) and determine the role of aquaporin-1 (AQP1) in this process, we established an AA-I-induced EMT model in human proximal tubular epithelial cells (HK-2 cells). Morphological examination, MTT assay, and Western blot analysis were performed. Aquaporin 1 (AQP1) and several EMT-related proteins were detected, thereby suggesting the occurrence of AA-I-induced EMT. Two main pathways of transforming growth factor-β (TGF-β) signaling, namely, Smad-dependent and Smad-independent signaling pathways, were also detected. The results showed that the TGF-β / Smad-independent signaling pathways (β-catenin, Ras-Raf-Erk1/2 signaling pathways) were activated, and AQP1 expression was decreased during the AA-I induced EMT on HK-2 cells. With the presence of TGF-β1 receptor inhibitor (LY364947) and Erk1/2 inhibitor (PD98059), AQP1 expression was altered by PD98059, suggested that AQP1 could be adjusted by Erk1/2 signaling. Moreover, the inhibitory effect of AA-I on AQP1 was stronger than that of TGF-β1, suggested that AQP1 may be an important target on AAN clinical therapy.

MicroRNA Profiling in Patients with Upper Tract Urothelial Carcinoma Associated with Balkan Endemic Nephropathy

Balkan endemic nephropathy (BEN) is a disease that affects people that live in the alluvial plains along the tributaries of the Danube River in the Balkan region. BEN is a chronic tubulointerstitial disease with a slow progression to terminal renal failure and has strong association with upper tract urothelial carcinoma (UTUC). There are several hypotheses about the etiology of BEN, but only the toxic effect of aristolochic acid has been confirmed as a risk factor in the occurrence of the disease. Aberrantly expressed miRNAs have been shown to be associated with many types of cancers. A number of studies have investigated the expression of microRNAs in urothelial carcinoma, mainly on urothelial bladder cancer, and only a few have included patients with UTUC. Here we present the first study of microRNA profiling in UTUC tissues from patients with BEN (BEN-UTUC) and patients with UTUC from nonendemic Balkan regions (non-BEN-UTUC) in comparison to normal kidney tissues. We found 10 miRNAs that were differentially expressed in patients with BEN-UTUC and 15 miRNAs in patients with non-BEN-UTUC. miRNA signature determined in BEN-UTUC patients differs from the non-BEN-UTUC patients; only miR-205-5p was mutual in both groups.

Smad7 protects against chronic aristolochic acid nephropathy in mice

Chronic Aristolochic Acid Nephropathy (AAN) is a progressive chronic kidney disease related to herb medicine. However, treatment for chronic AAN remains ineffective. We report here that Smad7 is protective and has therapeutic potential for chronic AAN. In a mouse model of chronic AAN, progressive renal injury was associated with a loss of renal Smad7 and disruption of Smad7 largely aggravated the severity of chronic AAN as demonstrated by a significant increase in levels of 24-hour urinary protein excretion, serum creatinine, and progressive renal fibrosis and inflammation. In contrast, restored Smad7 locally in the kidneys of Smad7 knockout mice prevented the progression of chronic AAN. Further studies revealed that worsen chronic AAN in Smad7 knockout mice was associated with enhanced activation of TGF-β/Smad3 and NF-κB signaling pathways, which was reversed when renal Smad7 was restored. Importantly, we also found that overexpression of Smad7 locally in the kidneys with established chronic AAN was capable of attenuating progressive chronic AAN by inactivating TGF-β/Smad3-medated renal fibrosis and NF-κB-driven renal inflammation. In conclusion, Smad7 plays a protective role in the pathogenesis of chronic AAN and overexpression of Smad7 may represent a novel therapeutic potential for chronic AAN.

Association of dialysis with the risks of cancers

Background

To increase the survival span after dialysis in patients with end-stage renal disease (ESRD), identifying specific cancer risks is crucial in the cancer screening of these patients. The aim of this study was to investigate the risks of various cancers in an incident dialysis group in comparison with a non-dialysis group.

Method

We conducted a nationwide cohort study by using data from the Taiwan National Health Insurance Research Database. Patients who initially received long-term dialysis between January 1997 and December 2004, were selected and defined as the dialysis group and were matched with the non-dialysis patients (control group) according to age, sex, and index year. Competing risk analysis was used to estimate cumulative incidence and subdistribution hazard ratios (SHRs) of the first cancer occurrence.

Results

After consideration for the competing risk of mortality, the dialysis group showed a significantly higher 7-year cancer incidence rate than did the control group (6.4%; 95% confidence interval [CI], 6.0%-6.7% vs 1.7%; 95% CI, 1.4%-2.1%; P <0.001).The modified Cox proportional hazard model revealed that the dialysis group had significantly association with increased risks for all cancers (SHR, 3.43; 95% CI, 3.02-3.88). The risk of cancers was dominated in younger and female patients. Specific cancer risks were significantly higher in the dialysis group particularly in the development of oral, colorectal, liver, blood, breast, renal, upper urinary tract, and bladder cancer than in the control group. Multivariable stratified analyses confirmed the association between long-term dialysis and cancer in all subgroups of patients.

Conclusions

Dialysis is associated with a higher risk of cancer in patients with ESRD. However, cancer screening in ESRD population should be a selective approach, based on individual patient health condition and life expectancy.

Localization of Aristolochic Acid in Mouse Kidney Tissues by Immunohistochemistry Using an Anti-AA-I and AA-II Monoclonal Antibody

Aristolochic acids (AAs) are found in herbal medicines of Aristolochiaceae plants, including Aristolochia and Asarum species. AAs are associated with a rapidly progressive interstitial nephritis, which is called aristolochic acid nephropathy (AAN). However, the in-situ localization of AAs in the target organ, the kidney, has not been investigated yet. In the present study, the accumulation of aristolochic acid I (AA-I) in mouse kidney was revealed by immunoperoxidase light microscopy as well as colloidal gold immunoelectron microscopy (IEM) based on an anti-AA-I and AA-II monoclonal antibody (mAb). Male BALB/c mice were treated with 1.25 or 2.50 mg kg-1 of AA-I per day for 5 days. Paraffin sections and ultra-thin sections of kidney tissue were respectively prepared. Under light microscopy, the apical surface of proximal tubules was strongly stained for AA-I, whereas no obvious immunostaining was found in the distal tubules and glomerulus, which remained relatively intact. Under electron microscopy, epithelial cells of the proximal tubules, distal tubules and collecting tubules were broken to various degrees. Gold labeling in the proximal and distal tubules was stronger than that in the collecting tubules. In renal tubules, immunogold signals of AA-I tended to accumulate in the mitochondria and peroxisomes, though the signals could be observed all over the cell. Gold signals were also found in the erythrocytes of glomeruli. The MAb against AA-I and AA-II provides a clue for the identification of proteins or factors which might interact with AA-I and thus induce targeted damage of kidney.

Aristolochic acid induced suicidal erythrocyte death

BACKGROUND/AIMS

Aristolochic Acid, a component of Aristolochia plants, has been shown to cause acute kidney injury, renal aristolochic acid nephropathy, Balkan endemic nephropathy, and urothelial carcinoma. Aristolochic acid nephropathy may be associated with severe anemia. The anemia could theoretically be due to stimulation of eryptosis, the suicidal death of erythrocytes characterized by cell shrinkage and cell membrane scrambling with translocation of phosphatidylserine to the erythrocyte cell membrane surface. Signalling involved in the stimulation of eryptosis include increase of cytosolic Ca(2+)-activity ([Ca(2+)]i) and formation of ceramide.

METHODS

Cell volume was estimated from forward scatter, phosphatidylserine-exposure from annexin V binding, [Ca(2+)]i from Fluo3 fluorescence, and ceramide abundance from binding of fluorescent antibodies in flow cytometry.

RESULTS

A 48 hours exposure to Aristolochic Acid (≥ 75 µg/ml) was followed by a significant decrease of forward scatter and increase of annexin-V-binding. The effects were paralleled by a significant increase of [Ca(2+)]i and significantly blunted, but not abrogated by removal of extracellular Ca(2+). Aristolochic Acid further significantly increased ceramide abundance.

CONCLUSIONS

Aristolochic Acid triggers eryptosis, an effect at least in part due to entry of extracellular Ca(2+) and ceramide formation.

Chinese herbs containing aristolochic acid associated with renal failure and urothelial carcinoma: a review from epidemiologic observations to causal inference

Herbal remedies containing aristolochic acid (AA) have been designated to be a strong carcinogen. This review summarizes major epidemiologic evidence to argue for the causal association between AA exposure and urothelial carcinoma as well as nephropathy. The exposure scenarios include the following: Belgian women taking slimming pills containing single material Guang Fang Ji, consumptions of mixtures of Chinese herbal products in the general population and patients with chronic renal failure in Taiwan, occupational exposure in Chinese herbalists, and food contamination in farming villages in valleys of the Danube River. Such an association is corroborated by detecting specific DNA adducts in the tumor tissue removed from affected patients. Preventive actions of banning such use and education to the healthcare professionals and public are necessary for the safety of herbal remedies.

Evidence-based toxicity evaluation and scheduling of Chinese herbal medicines

ETHNOPHARMACOLOGICAL RELEVANCE

While there is an increasing number of toxicity report cases and toxicological studies on Chinese herbal medicines, the guidelines for toxicity evaluation and scheduling of Chinese herbal medicines are lacking.

AIM

The aim of this study was to review the current literature on potentially toxic Chinese herbal medicines, and to develop a scheduling platform which will inform an evidence-based regulatory framework for these medicines in the community.

MATERIALS AND METHODS

The Australian and Chinese regulations were used as a starting point to compile a list of potentially toxic herbs. Systematic literature searches of botanical and pharmaceutical Latin name, English and Chinese names and suspected toxic chemicals were conducted on Medline, PubMed and Chinese CNKI databases.

RESULTS

Seventy-four Chinese herbal medicines were identified and five of them were selected for detailed study. Preclinical and clinical data were summarised at six levels. Based on the evaluation criteria, which included risk-benefit analysis, severity of toxic effects and clinical and preclinical data, four regulatory classes were proposed: Prohibited for medicinal usage, which are those with high toxicity and can lead to injury or death, e.g., aristolochia; Restricted for medicinal usage, e.g., aconite, asarum, and ephedra; Required warning label, e.g., coltsfoot; and Over-the-counter herbs for those herbs with a safe toxicity profile.

CONCLUSION

Chinese herbal medicines should be scheduled based on a set of evaluation criteria, to ensure their safe use and to satisfy the need for access to the herbs. The current Chinese and Australian regulation of Chinese herbal medicines should be updated to restrict the access of some potentially toxic herbs to Chinese medicine practitioners who are qualified through registration.

Factors associated with CKD in the elderly and nonelderly population

BACKGROUND AND OBJECTIVES

The risk factors for CKD in different age groups remain unknown. This community-based study aimed to identify the risk factors for CKD in elderly and nonelderly patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A multistage sampling survey for CKD was conducted in 2007 in Kaohsiung County, an area with the highest prevalence of dialysis in the world. CKD was defined as proteinuria in at least the microalbuminuric stage or an estimated GFR (eGFR) of <60 ml/min per 1.73 m(2). The factors for CKD in elderly and nonelderly patient groups were identified (with age 60 years as a cutoff value).

RESULTS

The analyses included 3352 participants, of whom 687 had CKD. The weighted prevalence of CKD was 19.4% (95% confidence interval [CI], 18.0%-20.7%). Elderly patients typically presented with low eGFR and nonelderly patients, with proteinuria. Age, annual income, use of oral analgesics, metabolic syndrome, hyperuricemia, and hemoglobin were risk factors for CKD in both age groups. In elderly patients, risk factors were medical history of diabetes mellitus, CKD, stroke, and not using analgesic injection (odds ratios [95% CIs], 3.58 [2.06-6.22], 3.66 [1.58-8.43], 3.89 [1.09-13.87], 2.27 [1.21-4.17], respectively). In nonelderly patients, associated risk factors for CKD were gout, hepatitis B virus infection, and use of the Chinese herbal medicine Long Dan Xie Gan Tang (odds ratios [95% CIs], 3.15 [1.96-5.07], 1.66 [1.09-2.53], and 8.86 [1.73-45.45], respectively).

CONCLUSIONS

The risk factors for CKD vary by age.

Does Chinese herb nephropathy account for the high incidence of end-stage renal disease in Taiwan?

BACKGROUND

The incidence of end-stage renal disease (ESRD) in Taiwan ranks highest in the world, but the incidence of Chinese herb nephropathy (CHN) is unknown in this country where Chinese herb use is common.

METHODS

The etiologies of incident ESRD cases from 2000 to 2004 in a single tertiary referral medical center in Taiwan were independently reviewed by two nephrologists through medical records and telephone interview. Patients with obvious causes of ESRD were not diagnosed with CHN, in spite of Chinese herb use. Three categories of CHN (A, B and C) were defined according to the stringency of evidence.

RESULTS

Obvious causes of ESRD were identified in 1,359 out of 1,696 newly diagnosed ESRD patients. Among the remainders, 263 had histories of Chinese herb use; 164 patients (mean age 52.7 ± 13.2 years, female 71.6%) had CHN (category A: 51, category B: 38 and category C: 75). Among the three categories, there was no difference in age, gender, body mass index (BMI) or elapsed time from Chinese herb use to the detection of renal failure. In comparison with non-CHN patients (n = 99), more CHN patients were female, had lower BMI, lower blood pressure, shorter duration of Chinese herb use, less severe proteinuria, smaller kidney size, lower levels of hemoglobin and higher serum chloride levels (all p values <0.01).

CONCLUSION

Based on highly stringent diagnostic criteria, nearly 10% of incident ESRD cases were due to CHN. CHN represents a significant cause of ESRD in Taiwan.

Increased risks of upper tract urothelial carcinoma in male and female chinese herbalists

BACKGROUND/PURPOSE

It has been shown that herbs that contain aristolochic acid induce urological cancer. Chinese herbalists have easy access to such herbs. Our previous mortality study has shown a significantly increased risk of urological cancer in female but not male herbalists. To re-examine this risk in male herbalists, the incidence of urological cancer was analyzed.

METHODS

We enrolled all 6550 Chinese herbalists in Taiwan registered during 1985-2000, and we retrospectively followed the development of cancer until 2001 by analysis of data collected from the Taiwan Cancer Registry. Standardized incidence ratios (SIRs) were calculated for urological cancers in herbalists and compared with those for the general population in Taiwan.

RESULTS

There were 30 newly diagnosed cases of urological cancer and most of them were transitional cell carcinoma (93.1%). The mean age at diagnosis for urothelial carcinoma was 51.6 years, and 51.9% were in the upper urinary tract. After adjustment for age and sex, the SIR for all urological cancers was 3.51 [(95% confidence interval (CI): 2.37-5.01]. When stratified by location, the SIRs for kidney and upper urinary tract cancers and bladder cancer were 4.24 (95% CI: 2.47-6.80) and 2.86 (95% CI: 1.52-4.89), respectively. When analyzed by sex, the SIRs for all urological cancers, kidney and upper urinary tract cancers, and bladder cancer were also significantly increased in male herbalists.

CONCLUSION

The significant risk of urothelial carcinoma noted in male herbalists increases our suspicion that this is an occupational disease that renders regular health assessment of herbalists an urgent necessity.

Pharmacokinetics of p-Aminohippuric Acid and Inulin in Rabbits with Aristolochic Acid Nephropathy

The characteristics of aristolochic acid nephropathy (AAN) are interstitial fibrosis and atrophy of the proximal tubules, but with no change in glomeruli. To investigate the effects of AA on renal functions and the pharmacokinetics (PKs) of p-aminohippuric acid (PAH) and inulin, New Zealand white rabbits were used in this study. The plasma concentrations of PAH and inulin were determined by validated HPLC methods. After a single intravenous administration of 0.5 mg/kg aristolochic acid sodium (AANa), rabbits exhibited mild to moderate nephrotoxicity on the 7th day. Significant tubulointerstitial damage to kidney specimens was found, but there were no remarkable glomerular changes. Clearance rates of PAH and inulin both significantly decreased in AANa-treated rabbits. In addition, there was a significant correlation among the degree of tubulointerstitial changes and PK parameters of PAH after AANa administration, but no correlation was noted with the PKs of inulin. With mild to moderate AAN in rabbits, the renal plasma flow significantly decreased by 55%, and the glomerular filtration rate also significantly decreased by 85%. In conclusion, major renal lesions were found on proximal tubules after AANa administration. The PKs of PAH and inulin significantly changed, and kidney functions, including the RPF and GFR, were reduced.

Epidemiology, impact and preventive care of chronic kidney disease in Taiwan

Chronic kidney disease (CKD) has emerged as a global public health burden. Taiwan has the highest incidence and prevalence rates of end-stage renal disease (ESRD) in the world. In this review, the following key issues of CKD in Taiwan are addressed: epidemiological data, underlying diseases patterns, risk factors, public health concerns and a preventive project. Prevalence of CKD are reported to be 6.9% for CKD stage 3-5, 9.83% for clinically recognized CKD and 11.9% for CKD stage 1-5. However, overall awareness of CKD is low, 9.7% for CKD stage 1-3 and 3.5% for stage 1-5. Diabetes mellitus (43.2%), chronic glomerulonephritis (25.1%), hypertension (8.3%) and chronic interstitial nephritis (2.8%) are four major underlying renal diseases of ESRD. Older age, diabetes, hypertension, smoking, obesity, regular use of herbal medicine, family members (both relatives and spouses), chronic lead exposure and hepatitis C are associated with higher risk for CKD. Impact of CKD increases risk of all-cause mortality and cardiovascular diseases, especially in those with overt proteinuria and advanced CKD stages. These impacts lead to increased medical costs. The nationwide CKD Preventive Project with multidisciplinary care program has proved its effectiveness in decreasing dialysis incidence, mortality and medical costs. It is crucially significant from Taiwan experience on CKD survey and preliminary outcome of the preventive project. Provision of a more comprehensive public health strategy and better care plan for CKD should be achieved by future international collaborative efforts and research.

Population-based case-control study of Chinese herbal products containing aristolochic acid and urinary tract cancer risk

Background

Consumption of Chinese herbs that contain aristolochic acid (eg, Mu Tong) has been associated with an increased risk of urinary tract cancer.

Methods

We conducted a population-based case–control study in Taiwan to examine the association between prescribed Chinese herbal products that contain aristolochic acid and urinary tract cancer. All patients newly diagnosed with urinary tract cancer (case subjects) from January 1, 2001, to December 31, 2002, and a random sample of the entire insured population from January 1, 1997, to December 31, 2002 (control subjects), were selected from the National Health Insurance reimbursement database. Subjects who were ever prescribed more than 500 pills of nonsteroidal anti-inflammatory drugs and/or acetaminophen were excluded, leaving 4594 case patients and 174 701 control subjects in the final analysis. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by using multivariable logistic regression models for the association between prescribed Chinese herbs containing aristolochic acid and the occurrence of urinary tract cancer. Models were adjusted for age, sex, residence in a township where black foot disease was endemic (an indicator of chronic arsenic exposure from drinking water [a risk factor for urinary tract cancer]), and history of chronic urinary tract infection. Statistical tests were two-sided.

Results

Having been prescribed more than 60 g of Mu Tong and an estimated consumption of more than 150 mg of aristolochic acid were independently associated with an increased risk for urinary tract cancer in multivariable analyses (Mu Tong: at 61–100 g, OR = 1.6, 95% CI = 1.3 to 2.1, and at >200 g, OR = 2.1, 95% CI = 1.3 to 3.4; aristolochic acid: at 151–250 mg, OR = 1.4, 95% CI = 1.1 to 1.8, and at >500 mg, OR = 2.0, 95% CI = 1.4 to 2.9). A statistically significant linear dose–response relationship was observed between the prescribed dose of Mu Tong or the estimated cumulative dose of aristolochic acid and the risk of urinary tract cancer (P < .001 for both).

Conclusions

Consumption of aristolochic acid–containing Chinese herbal products is associated with an increased risk of cancer of the urinary tract in a dose-dependent manner that is independent of arsenic exposure.

Increased risks of chronic kidney disease associated with prescribed Chinese herbal products suspected to contain aristolochic acid

AIM

Nephropathy associated with aristolochic acid (AA) has been documented by human and animal studies. Ancient Chinese herbology claimed to reduce toxicity in their mixtures. It was the objective of this study to determine the risk of chronic kidney disease (CKD) associated with AA-related Chinese herbal products (CHP) or mixtures of herbs in a national cohort.

METHODS

A retrospective follow-up study was conducted, using a systematic random sample (200 000 people) in the National Health Insurance reimbursement database during 1997-2002. The incidence rates of CKD and end-stage renal disease (ESRD) were calculated for the whole sample and those that had used CHP suspected to contain AA. Cox regression models were constructed to control potential confounders, including age, sex, hypertension, diabetes mellitus, and use of non-steroidal anti-inflammatory drugs and acetaminophen.

RESULTS

A total of 199 843 persons were included in the final analysis, 102 464 (51.3%) men and 97 379 (48.7%) women, with an average incidence rate of 1964/10(6) person-years for CKD and 279/10(6) person-years for ESRD. After controlling other risk factors, the hazard ratios for development of CKD seemed to increase for patients that had consumed more than 30 g Mu-Tong, and more than 60 g Fangchi.

CONCLUSION

Prescription of more than 30 g Mu-Tong or more than 60 g Fangchi CHP was associated with an increased risk of developing CKD. In addition to prohibiting the use of Guan-Mu-Tong and Guang-Fangchi, patients who have used these CHP should continue to be followed up.

End-stage renal disease in Taiwan: a case-control study

Background

Taiwan has the highest incidence of end-stage renal disease (ESRD) in the world. The epidemiologic features of ESRD, however, have not been investigated. In this case–control study, we evaluated the risk of ESRD associated with a number of putative risk factors.

Methods

We studied 200 patients among whom ESRD had been newly diagnosed between 1 January 2005 and 31 December 2005; 200 controls were selected from among relatives of patients treated in the general surgery unit. Using a structured questionnaire, we collected information related to socioeconomic factors, history of disease, regular blood or urine screening, lifestyle, environmental exposure, consumption of vitamin supplements, and regular drug use at 5 years before disease onset.

Results

Our primary multivariate risk models indicated that low socioeconomic status was a strong predictor of ESRD (education: odds ratio [OR], 2.78; 95% confidence interval [CI], 1.49–5.19; income: OR, 2.86, 95% CI, 1.48–5.52), even after adjusting for other risk factors. Other significant predictors for ESRD were a history of hypertension (OR, 3.63–3.90), history of diabetes (OR, 3.85–5.50), and regular intake of folk remedies or over-the-counter Chinese herbs (OR, 10.84–12.51). Regular intake of a multivitamin supplement 5 years before diagnosis was associated with a decreased risk of ESRD (OR, 0.12–0.14).

Conclusions

Our findings indicate that low socioeconomic status, history of hypertension, diabetes, and regular use of folk remedies or over-the-counter Chinese herbs were significant risk factors for ESRD, while regular intake of a multivitamin supplement was associated with a decreased risk of ESRD.

Increased mortality risk for cancers of the kidney and other urinary organs among Chinese herbalists

BACKGROUND

A national survey in Taiwan has shown that Chinese herbal therapy increases the risk of chronic kidney disease. However, it is unknown whether herbal therapy will increase the risk of urological cancers. The purpose of this study was to determine whether Chinese herbalists are at higher risk for urological cancers.

METHODS

We studied all Chinese herbalists in Taiwan that were registered in the Chinese Herbalist Labor Union between 1985 and 2000. We retrospectively followed their survival status and causes of death using the National Mortality Registry Database from 1985 to 2004. Standardized mortality ratios (SMRs) for urological cancers in herbalists were calculated and compared with those of the general population of Taiwan.

RESULTS

A total of 6548 Chinese herbalists were enrolled and 88,289 person-years were accrued during the observation period. After adjustment for age and sex, the SMR for urological cancers was significantly higher for Chinese herbalists than for the general population (SMR = 3.10; 95% CI: 1.41-5.87). When further stratified by location, the SMR for kidney cancer and other urinary organ cancers (SMR = 3.81; 95% CI: 1.39-8.28) except bladder cancer (SMR = 2.26; 95% CI: 0.47-6.59) were significantly higher for the Chinese herbalists. The SMR for chronic and unspecified nephritis, renal failure, and renal sclerosis were also significantly higher for herbalists (SMR = 2.40; 95% CI: 1.40-3.84).

CONCLUSIONS

Chinese herbalists have a significantly higher risk for urological cancers. This increased risk among herbalists highlights the urgent need for safety assessments of Chinese herbs.

Prescription profile of potentially aristolochic acid containing Chinese herbal products: an analysis of National Health Insurance data in Taiwan between 1997 and 2003

Background

Some Chinese herbal products (CHPs) may contain aristolochic acid (AA) or may be adulterated by the herbs suspected of containing AA which is nephrotoxic and carcinogenic. This study aims to identify the risk and the prescription profile of AA-containing CHPs (AA-CHPs) in Taiwan.

Methods

A longitudinal analysis was conducted on a randomly sampled cohort of 200,000 patients using the data from the National Health Insurance (NHI) in Taiwan between 1997 and 2003.

Results

During the 7-year study period, 78,644 patients were prescribed with AA-CHPs; most patients were females, or middle-aged, or both. A total of 526,867 prescriptions were made to use 1,218 licensed AA-CHPs. Over 85% of the AA-exposed patients took less than 60 g of AA-herbs; however, about 7% were exposed to a cumulated dose of over 100 g of Radix et Rhizoma Asari (Xixin), Caulis Akebiae (Mutong) or Fructus Aristolochiae (Madouling). Patients of respiratory and musculoskeletal diseases received most of the AA-CHP prescriptions. The most frequently prescribed AA-CHPs Shujing Huoxie Tang, Chuanqiong Chadiao San and Longdan Xiegan Tang, containing Radix Stephaniae Tetrandrae, Radix et Rhizoma Asari and Caulis Akebiae, respectively.

Conclusion

About one-third of people in Taiwan have been prescribed with AA-CHPs between 1997 and 2003. Although the cumulated doses were not large, further actions should be carried out to ensure the safe use of AA-CHPs.

Herbal Therapy Is Associated With the Risk of CKD in Adults Not Using Analgesics in Taiwan

BACKGROUND

Taiwan has the greatest incidence rate of end-stage renal disease in the world. Several cases of Chinese herb nephropathy were reported in Taiwan. Therefore, we studied the association between herbal therapy and chronic kidney disease (CKD) in Taiwan.

STUDY DESIGN

Cross-sectional survey.

SETTING & PARTICIPANTS

1,740 adults in the Nutrition and Health Survey in Taiwan (1993 to 1996).

PREDICTOR

Herbal and analgesic therapy.

OUTCOMES & MEASUREMENTS

CKD after adjustment for potential confounding variables.

RESULTS

Among medication users, prevalences of herbal therapy and analgesic use were 21.6% and 13.2%, respectively. The prevalence of CKD was 9.9%. Participants with CKD were older and had more analgesic use, diabetes, hypertension, and cardiovascular disease. Analgesic use was associated independently and positively with CKD (odds ratio, 2.2; 95% confidence interval, 1.4 to 3.5; P = 0.003) and CKD stage (odds ratio, 2.3; 95% confidence interval, 1.4 to 3.6; P = 0.003). Conversely, herbal therapy was associated independently and positively with CKD (odds ratio, 1.39; 95% confidence interval, 1.2 to 1.7; P = 0.002) and CKD stage (odds ratio, 1.38; 95% confidence interval, 1.1 to 1.7; P = 0.004) only in participants who did not use analgesics.

LIMITATIONS

Because this was a cross-sectional study, cause and effect could not be ascertained.

CONCLUSIONS

Herbal therapy was associated with CKD in adults in Taiwan who did not use analgesics.

Renal diagnosis of chronic hemodialysis patients with urinary tract transitional cell carcinoma in Taiwan

BACKGROUND

Transitional cell carcinoma (TCC) is the most common malignancy in dialysis patients of Taiwan. The reason for such a high incidence of TCC is undetermined. The correlation between the underlying renal disease and the development of TCC was investigated.

METHODS

The authors retrospectively reviewed the clinical data and outcome of 1537 chronic hemodialysis (HD) patients from 1993 to 2002. The incidence of TCC was computed. The Cox regression method was used to analyze the role of potential risk factors.

RESULTS

After a mean dialysis duration of 46.5 months, 26 (1.69%) patients with TCC were diagnosed. The standardized incidence ratio (SIR) of TCC was 48.2 as compared with the general population and the SIR of TCC seemed higher in women (65.1) and in the age group 50 to 54 years (173.6). Of them, most cases showed no definite etiology. All these cases showed bilateral contracted kidneys. Nonnephrotic proteinuria was found in all cases and trace glucosuria was found in 17 (65%). Painless gross hematuria was the cardinal symptom and distant metastasis was rare. Also, TCC in upper urinary tracts were common and found in 14 (54%) of patients. Age at the time of dialysis, female sex, compound analgesic use, and Chinese herb use had statistical significance as risk factors (P < .05).

CONCLUSIONS

Chronic HD patients have a high risk of TCC in Taiwan, especially in female and middle-aged patients. The study indicated that chronic tubulointerstitial nephritis (CTIN) is the most likely underlying renal disease in HD patients with TCC, a high percentage of the CTIN related to the usage of Chinese herbs or compound analgesics may contribute to the development of TCC, whereas diabetes or chronic glomerulonephritis play only a minor role.

Mast cell, a promising therapeutic target in tubulointerstitial fibrosis

Tubulointerstitial fibrosis is a final common pathway to the eventual structural desolation of kidneys. However, the mechanism involved in this phenomenon is still poorly understood, and current therapies are ineffective or only marginally effective. Mast cell has a variety of physiological and pathological functions through the production of heparin, histamine, neutrophil chemoattractants, immunoregulatory cytokines, and mast cell-specific serine proteases tryptase and chymase. The survival and proliferation of mast cell are dependent upon stem cell factor. Presently, mast cells are known to participate in the pathogenesis of tubulointerstitial fibrosis in many kidney diseases. Several therapeutic approaches to inhibit mast cell activation have already demonstrated some clinical utility in tissue fibrosis or inflammatory diseases such as the use of mast cell stabilizers, inhibitors of tryptase or chymase, blockade of stem cell factor and anti-IgE therapy. We hypothesize that mast cell has a significant role in the progression of tubulointerstitial fibrosis, thus the treatment strategies based on mast cell appear to be promising in these conditions. Development of these novel therapeutic approaches will enable us to target any types of renal disease.

Aristolochic acid I-induced DNA damage and cell cycle arrest in renal tubular epithelial cells in vitro

DNA damage is a critical event preceding cellular apoptosis or necrosis. This study was carried out to investigate the effect of aristolochic acid I (AAI) on DNA damage and cell cycle in porcine proximal tubular epithelial cell lines (LLC-PK1 cells). LLC-PK1 cells were stimulated with AAI at the concentrations of 80, 320, and 1,280 ng/ml for 24 h. DNA damage was examined by comet assay and the cell cycle was assayed by flow cytometry (FCM), cellular apoptosis and lysis were examined simultaneously. Cellular nuclear changes were observed by electron microscopy and the expression of wild-type p53 protein and mRNA were measured by FCM and RT-PCR. We found that AAI-induced DNA damage prior to apoptosis and lysis in LLC-PK1 cells in a dose-dependent manner (P<0.01). The percentage of cells in the G2/M phase that were treated with AAI (320 and 1,280 ng/ml) for 24 h increased significantly (P<0.01). Electron micrographs showed the nuclear abnormalities in AAI-treated cells. The expression of p53 protein and mRNA did not change in the AAI-treated cells. AAI may cause DNA damage and cell cycle arrest in LLC-PK1 cells through a wild-type p53-independent pathway, prior to apoptosis or necrosis. This study on the molecular mechanism of AAI-induced toxicity may explain why tubular epithelial cells present limited proliferation and regeneration abilities in the clinical presentation of AAI-associated nephrotoxicity.

Cytotoxicity of Phenanthrenes Extracted from Aristolochia contorta in Human Proximal Tubular Epithelial Cell Line

BACKGROUND/AIMS

Aristolochic acid nephropathy, a progressive tubulointerstitial renal disease, is predominantly a result of aristolochic acid I (AA-I) intoxication. However, other unidentified phytotoxins have indeed been postulated as the cause of this unique interstitial nephropathy. The purpose of this study was to investigate the cytotoxicity of other phenanthrene derivatives extracted from Aristolochia contorta in the human proximal tubular epithelial cell line HK-2.

METHODS

After HK-2 cells were incubated with an indicated concentration of test compounds for 24 h, cell viability was assessed by lactate dehydrogenase (LDH) leakage assay (cell membrane damage) in combination with MTT assay (metabolic capability). Cellular morphologic assessments were performed with a phase-contrast inverted microscope and transmission electron microscope.

RESULTS

In all test compounds at 5 microg/ml, AA-I, 7-methoxy-aristololactam IV and aristololactam IVa showed cytotoxic activity in HK-2 cells in both MTT assay and LDH leakage assay (p < 0.01). At high concentration (5-80 microg/ml), these three compounds caused a dose-dependent decrease in MTT reduction and a dose-dependent increase in LDH leakage compared to non-treated cells (p <0.01). In LDH leakage assay, 40 mug/ml 7-methoxy-aristololactam IV induced a 1.58-fold LDH leakage compared to AA-I at the same concentration (p < 0.01). Moreover, the IC50 of these three compounds were 16.675 microg/ml for AA-I, 4.535 microg/ml for 7-methoxy-aristololactam IV, and 30.244 microg/ml for aristololactam IVa in MTT assay. The cellular morphologic assessments suggest interactions with cell membrane and intracellular structures such as lysosome and mitochondria are likely to be involved in cell injury induced by these three compounds.

CONCLUSION

The potency of cytotoxic activity of aristololactam IVa and 7-methoxy-aristololactam IV extracted from A. contorta is similar to or even stronger than that of AA-I.

Mast cell infiltration associated with tubulointerstitial fibrosis in chronic Aristolochic Acid Nephropathy

Aristolochic Acid Nephropathy (AAN) is regarded as a kind of toxic nephropathy caused by the formation of DNA- aristolochic acid adducts in renal parenchymal cells. However, the underlying mechanisms driving the progression of renal interstitial fibrosis in AAN still remains unclear. This study aims to elucidate the role of some immunological factors, especially mast cells (MCs), in the pathogenesis of AAN. Sixteen patients with AAN were enrolled in this study, including five acute and 11 chronic AAN. Monoclonal antibodies against human tryptase, alpha smooth muscle actin (alpha-SMA), and CD68 were applied on serial sections, which were further counterstained with Periodic Acid-Schiff. It was found that massive tryptase-positive MCs were observed in the fibrotic areas in chronic AAN, especially around thickened tubular basement membranes where myofibroblasts accumulated too. In contrast, MCs infiltrated to a less extent in acute AAN, and were barely found in normal control kidneys. In chronic AAN, the number of MCs in the tubulointerstitium was positively correlated with the degree of renal fibrosis (r=0.64, P <0.05), but not with serum creatinine levels. Meanwhile, the recruitment of MCs into the renal interstitium is accompanied with local proliferation of myofibroblasts. Macrophages were not abundant, neither in acute nor in chronic AAN. Our findings show for the first time that mast cell infiltration seems to be associated with the progression of fibrosis in the renal tubulointerstitium in chronic AAN.

Medicinal herbal extracts -- renal friend or foe? Part one: the toxicities of medicinal herbs

In recent years, an increasing percentage of people from industrialized countries have been using complementary and alternative medicines (CAM). This, combined with numerous warnings regarding the potential toxicity of these therapies, suggests the need for practitioners to keep abreast of the reported incidence of renal toxicity caused by the ingestion of medicinal herbs. The goal of the present two-part series, on the toxic or beneficial effects of medicinal herbs on renal health, is to provide practitioners with a summary of the most recent information as well as the means by which evidence for benefit or toxicity has been found. In this first article, we explore in vivo evidence of toxicity. Included are nephrotoxicity from aristolochic acid and other components within herbs, herb--drug interactions resulting in adverse renal effects, and renal toxicity from contaminants within the extracts. The review aims to provide a guide to encourage future toxicity studies and rigorous clinical trials.

Separation Methods for Toxic Components in Traditional Chinese Medicines

Traditional Chinese medicines (TCMs) with many unique functions for treating diseases have attracted the interest of people worldwide. They have been popularly utilized for therapy and health promotion in most Asian countries and even in many European and North American countries. However, it should be clearly noted that TCMs are mixtures with complicated composition usually containing hundreds, even thousands of chemically different constituents, and it is the multiple constituents that work synthetically to determine the ultimate effect of a formula of TCM. Meanwhile, some components with toxicity in some TCMs, having various negative effects on different parts of body, may do serious harm to people's health; such harm in particular requires our attention. In this article, applications of different chromatographic and electrophoretic techniques in the analysis of toxic components in TCMs in recent decades have been comprehensively reviewed and some hyphenated procedures (combinations of two kinds of measurement) applied in this field are also summarized.

Herbs and the kidney

The use of herbal therapy has increased dramatically in past years and may lead to renal injury or various toxic insults, especially in renal patients. In most countries, herbal products are not regulated as medicines. Herbal poisoning may be secondary to the presence of undisclosed drugs or heavy metals, interaction with the pharmacokinetic profile of concomitantly administered drugs, or association with a misidentified herbal species. Various renal syndromes were reported after the use of medicinal plants, including tubular necrosis, acute interstitial nephritis, Fanconi's syndrome, hypokalemia or hyperkalemia, hypertension, papillary necrosis, chronic interstitial nephritis, nephrolithiasis, urinary retention, and cancer of the urinary tract. It seems critical that caregivers be aware of the potential risk of such often underreported therapy and carefully question their patients about their use of this popular branch of alternative medicine.

Drug-induced tubulo-interstitial nephritis secondary to proton pump inhibitors: experience from a single UK renal unit

BACKGROUND

Acute tubulo-interstitial nephritis (TIN) is an important cause of acute renal failure, and is often caused by hypersensitivity to drugs. The aim of this study was to determine the aetiology of interstitial nephritis among an unselected cohort of patients, and to identify those drugs commonly implicated.

METHODS

A single-centre retrospective analysis was carried out of renal biopsy results from 296 consecutive patients between 1995 and 1999.

RESULTS

Acute TIN was identified in 24 (8.1%) biopsies. Eight out of 14 cases with presumed drug-related TIN could be attributed to the proton pump inhibitors omeprazole and lansoprazole. The two cases of lansoprazole-associated TIN are the first to be reported with this drug. The presentation and favourable response to treatment of these patients are described.

CONCLUSION

Drugs are the most common cause of interstitial nephritis in the population studied. Those drugs most commonly associated with interstitial nephritis were the proton pump inhibitors omeprazole and lansoprazole.

Aristolochic acid and 'Chinese herbs nephropathy': a review of the evidence to date

Chinese herbs nephropathy (CHN) is a rapidly progressive interstitial nephropathy reported after the introduction of Chinese herbs in a slimming regimen followed by young Belgian women. It is characterised by early, severe anaemia, mild tubular proteinuria and initially normal arterial blood pressure in half of the patients. Renal histology shows unusual extensive, virtually hypocellular cortical interstitial fibrosis associated with tubular atrophy and global sclerosis of glomeruli decreasing from the outer to the inner cortex. Urothelial malignancy of the upper urinary tract develops subsequently in almost half of the patients. Suspicion that the disease was due to the recent introduction of Chinese herbs in the slimming regimen was reinforced by identification in the slimming pills of the nephrotoxic and carcinogenic aristolochic acid (AA) extracted from species of Aristolochia. This hypothesis was substantiated by the identification of premutagenic AA-DNA adducts in the kidney and ureteric tissues of CHN patients. Finally, induction of the clinical features (interstitial fibrosis and upper urothelial malignancy) typical of CHN in rodents given AA alone removed any doubt on the causal role of this phytotoxin in CHN, now better called aristolochic acid nephropathy (AAN). AAN is not restricted to the Belgian cases. Similar cases have been observed throughout the world, but AA is sometimes incriminated on the basis of the known content of AA in the herbs. The possibility remains that in some individuals in whom AA has not been demonstrated, other phytotoxins might be implicated. Biological and morphological features of AAN are strikingly similar to those reported in another fibrosing interstitial nephropathy of still unknown aetiology, Balkan endemic nephropathy (BEN). Interestingly, AA was incriminated as the cause of BEN many years ago, a hypothesis yet to be fully explored. The intake of AA and the presence of tissular AA-DNA adducts in patients with an unequivocal diagnosis of BEN remains to be demonstrated. The tragic phenomenon of CHN, recognised only 10 years ago, has been at the root of significant research and progress both in nephrology and oncology. It has provided a fascinating opportunity to understand the link between a fibrosing interstitial nephropathy and urothelial carcinoma. It allows the categorisation of interstitial nephritis on the basis of histological findings, of initiating toxic substances and of associated clinical features. Finally, it has led to the withdrawal in several countries of a previously unsuspected carcinogenic and nephrotoxic substance.

Novel insights into renal fibrosis

PURPOSE OF REVIEW

Renal fibrosis characterizes a common endpoint of diverse renal diseases which leads to functional impairment ultimately resulting in terminal renal failure.

RECENT FINDINGS

Recent advances in this field led to the discovery of several novel mediators as well as novel aspects of known mediators. Studies on the origin and role of specific renal cell types involved in renal fibrosis identified bone marrow derived mesangial progenitors and offered substantial evidence for the concept of epithelial to mesenchymal transition. Much progress has also been made in better understanding of the interactions between different mediators and between mediators and renal target cells. Compounds designed on the basis of this current knowledge have proven to be potent inhibitors of the development of renal fibrosis or might even induce resolution of renal fibrosis.

SUMMARY

The number and diversity of recent studies in this field offer hope for new treatment regimes in our clinical efforts towards prevention and regression of progressive fibrosing renal diseases.