Flavonoid-induced acute nephropathy by Cupressus funebris Endl (Mourning Cypress)

Association between dietary intake of flavonoid and chronic kidney disease in US adults: Evidence from NHANES 2007-2008, 2009-2010, and 2017-2018

BACKGROUND

Studies investigating the relationship between flavonoid intake and chronic kidney disease (CKD) are limited. This study investigated the association between daily flavonoid intake and CKD in US adults by using data for 2007-2008, 2009-2010, and 2017-2018 from the National Health and Nutrition Examination Survey (NHANES) database.

METHODS

This study employed a cross-sectional design and used data from three cycles of the continuous NHANES: 2007-2008, 2009-2010, and 2017-2018. NHANES researchers collected data related to consumption of various food and beverages from participants by employing 24-h dietary recall questionnaires. CKD is defined as an estimated glomerular filtration rate of < 60 mL/min/1.73m2 or a urine albumin-to-creatinine ratio of ≥ 30 mg/g.

RESULTS

The odds ratios (OR) for CKD risk in the second (Q2), third (Q3), and fourth (Q4) quartiles of total flavonoid intake, compared with that in the first (Q1) quartile, were 0.780 (95% CI: 0.600, 1.015), 0.741 (95% CI: 0.573, 0.957), and 0.716 (95% CI: 0.554, 0.925), respectively (with a P value for the trend of 0.040). According to the restricted cubic spline analysis, total flavonoid intake exhibited a non-linear relationship with CKD risk (P < 0.001).

CONCLUSION

Our findings suggest that a potential J-shaped relationship was observed between total flavonoid consumption and CKD risk, with an inflection point at 69.58 mg/d. Our study indicates that a moderate intake of flavonoids may confer renal benefits which may offer novel strategies for CKD treatment.

A Systematic Review of Clinical Characteristics and Histologic Descriptions of Acute Tubular Injury

INTRODUCTION

The term "acute tubular injury" (ATI) represents histopathologic renal tubular injury and often manifests clinically as acute kidney injury (AKI). Studies systematically summarizing the clinical presentation and histological changes in human ATI are limited.

METHODS

We used a comprehensive search strategy to search human studies of ATI from 1936 to July 2019. We extracted study characteristics, clinical characteristics, and histologic descriptions of ATI by bright field, immunofluorescence, electron microscopy, and immunohistochemistry. We compared ATI histology as a function of tissue procurement type, timing, and etiologies.

RESULTS

We included 292 studies comprising a total of 1987 patients. The majority of studies (222 of 292, 76%) were single-center case reports. The mean age of included patients was 47 years. In native kidney biopsy cases, baseline, peak, and latest creatinine were 1.3 mg/dl, 7.19 mg/dl, and 1.85 mg/dl respectively, and biopsy was performed mostly after peak creatinine (86.7%, 391 of 451). We identified 16 histologic descriptions of tubular injury, including tubular cell sloughing (115 of 292, 39.4%), tubular epithelial flattening/simplification (110 of 292, 37.7%), tubular dilatation (109 of 292, 37.3%), and tubular cell necrosis (93 of 292, 31.8%). There was no difference in tubular injury histology among different tissue procurement types (native kidney biopsy, transplant kidney biopsy, and autopsy), among different etiologies, or between different tissue procurement timing (before or after creatinine peaks in native kidneys). Electron microscopy and immunohistochemistry were used in a minority of studies.

CONCLUSION

ATI manifests with diverse histologic changes. Efforts to establish protocols to harmonize biopsy practices, to handle kidney biopsy for tissue interrogation, and to report results across clinical practice are needed to improve our understanding of this complex disease.

Acute Kidney Injury in Asia: Disease Burden

Acute kidney injury (AKI) is a common and critical clinical disorder with non-negligible morbidity and mortality and remains a large public health problem. Asia, as the world's largest and most populous continent, is crucial in eliminating unsatisfactory outcomes of AKI. The diversities in climate, customs, and economic status lead to various clinical features of AKI across Asia. In this review, we focus on the epidemiologic data and clinical features of AKI in different Asian countries and clinical settings, and we show the huge medical and economic burden of AKI in Asian countries. Drugs and sepsis are the most common etiologies for AKI, however, an adequate surveillance system has not been well established. There is significant undertreatment of AKI in many regions, and medical resources for renal replacement therapy are not universally available. Although substantial improvement has been achieved, health care for AKI still needs improvement, especially in developing regions.

Bilobetin induces kidney injury by influencing cGMP-mediated AQP-2 trafficking and podocyte cell cycle arrest

BACKGROUND

Ginkgo biloba (Gb) extracts have been used as a traditional Chinese medicine. Gb contains flavonoids, which are considered to be its active ingredients and have been used in the treatment of a variety of diseases. However, few scientific research studies on the side effects of flavonoid in Gb have been reported.

PURPOSE

The present study aimed to investigate the effect of bilobetin on the kidney of Sprague-Dawley (SD) rats.

STUDY DESIGN AND RESULT

In this study, rats were injected with 50 mg/kg of bilobetin, a biflavone isolated from Gb, for 7 days and aristolochic acid was used as positive controls. The results showed that the body weight and urine output of the rats were dramatically decreased, and urinary protein increased after the intraperitoneal injection of bilobetin compared with the control group. Bilobetin treatment showed vacuolar degeneration in the renal tubular epithelium, glomerular atrophy by histostaining, and podocyte fusion by electron microscopy. This study further showed that bilobetin promoted the trafficking of aquaporin 2 (AQP-2) onto the plasma membrane to achieve the function of urine concentration by in vivo study in rats and in vitro study in IMCD-3 cells. The redistribution of AQP-2 is due to increased expression of cGMP in IMCD-3 cells, which in turn promoted the phosphorylation of AQP-2 at site Ser-256. The proteinuria caused by bilobetin may be attributed to podocyte cell cycle arrest at G2/M transition, which is may associated with AKT and MAPK signaling.

CONCLUSIONS

The current study showed that bilobetin has some side effects on kidneys at a dose of 50 mg/kg in SD rats and provides insight into the potential detrimental effects of monomeric ingredients in Gb.

Nephrotoxicity and Chinese Herbal Medicine

Chinese herbal medicine has been practiced for the prevention, treatment, and cure of diseases for thousands of years. Herbal medicine involves the use of natural compounds, which have relatively complex active ingredients with varying degrees of side effects. Some of these herbal medicines are known to cause nephrotoxicity, which can be overlooked by physicians and patients due to the belief that herbal medications are innocuous. Some of the nephrotoxic components from herbs are aristolochic acids and other plant alkaloids. In addition, anthraquinones, flavonoids, and glycosides from herbs also are known to cause kidney toxicity. The kidney manifestations of nephrotoxicity associated with herbal medicine include acute kidney injury, CKD, nephrolithiasis, rhabdomyolysis, Fanconi syndrome, and urothelial carcinoma. Several factors contribute to the nephrotoxicity of herbal medicines, including the intrinsic toxicity of herbs, incorrect processing or storage, adulteration, contamination by heavy metals, incorrect dosing, and interactions between herbal medicines and medications. The exact incidence of kidney injury due to nephrotoxic herbal medicine is not known. However, clinicians should consider herbal medicine use in patients with unexplained AKI or progressive CKD. In addition, exposure to herbal medicine containing aristolochic acid may increase risk for future uroepithelial cancers, and patients require appropriate postexposure screening.

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.

Nephrotoxicity of alternative medicine practice

The use of alternative medicine is highly prevalent around the world; in many areas, this is so because of lack of access to, or trust in, Western medicine, and also because they are considered "natural" and therefore safe. The kidney is an organ vulnerable to toxic insults by virtue of its anatomy and function. Reports of nephrotoxicity associated with alternative medicine use encompass all forms of renal dysfunction, ranging from electrolyte abnormalities and proteinuria to acute and CKD, renal failure, and death. In countries where intensive care and dialysis support are not available, mortality is high. Mechanisms of alternative medicine-associated kidney injury include direct nephrotoxicity, which may be augmented by underlying predisposing conditions such as dehydration; contamination, or adulteration of remedies; inappropriate use or preparation of a remedy; or interactions with other medications. The use of alternative medicines is underreported to clinicians. Because many patients strongly believe in the powers of alternative medicines, it is important that alternative medicines not be demonized as a whole, but that their use and consequences be closely observed and reported to build a more comprehensive understanding of their impact in our clinical practice and to foster research on the potential harm or, in some cases, possible benefits.

Effects of catechin-rich oil palm leaf extract on normal and hypertensive rats' kidney and liver

Catechin-rich oil palm (Elaeis guineensis) leaf extract (OPLE) possesses good ex vivo vasodilation, antioxidant and cardiovascular properties. This study evaluated the beneficial or toxic effects of OPLE on the liver and kidneys of normal and hypertensive rats. The OPLE (500mg/kg body weight) were administered orally to normal Wistar Kyoto rats, spontaneously hypertensive rats (SHR) and N-ω-nitro-l-arginine methyl ester (l-NAME)-induced NO-deficient hypertensive rats. The OPLE reduced hypertension in NO-deficient rats, but not in SHR. Hepatocytes or glomeruli injury and oxidative markers were high in hypertensive rats compared to normal rats, and they were reduced (p<0.05) by OPLE supplementation, even when there was no blood pressure reduction. Unlike the hypertensive drug captopril, the OPLE showed no toxicity to normal rats. The dose reported is equivalent 0.5g of catechins/day for humans or 2.5cups of tea. The catechins are from an abundant alternative source for potential use as functional food.

Thrombocytopenia as an adverse effect of complementary and alternative medicines, herbal remedies, nutritional supplements, foods, and beverages

BACKGROUND

Thrombocytopenia is a well-recognized adverse effect of many drugs. However, the association of thrombocytopenia with complementary/alternative medicines, herbal remedies, nutritional supplements, foods, and beverages has been rarely described, except for reports of thrombocytopenia caused by quinine-containing beverages.

OBJECTIVES

To systematically identify all published reports of thrombocytopenia associated with these substances and to assess the evidence supporting their causal association with thrombocytopenia.

METHODS

Eleven databases were searched to identify relevant published reports. A priori criteria were defined for article selection and assessment. Each selected article was independently assessed by the three authors to document the presence of the criteria and determine the level of evidence for a causal association of the reported substance with thrombocytopenia.

RESULTS

Twenty-seven articles were identified that reported the occurrence of thrombocytopenia with 25 substances (other than quinine). However, only six articles describing five substances (cow's milk, cranberry juice, Jui [Chinese herbal tea], Lupinus termis bean, and tahini [pulped sesame seeds]) reported clinical data supporting definite evidence of a causal association with thrombocytopenia. Four articles provided probable evidence for four additional substances, and five articles provided possible evidence for five additional substances. In the remaining articles, the association with thrombocytopenia was unlikely or the articles were excluded from review.

CONCLUSIONS

Reports of thrombocytopenia describing definite or probable evidence for an association of a complementary/alternative medicines, herbal remedies, nutritional supplements, foods, and beverages are rare. Whether the occurrence of thrombocytopenia with these substances is uncommon or unrecognized is unknown.

Autoimmune hemolytic anemia associated with a formulation of traditional Chinese medicines

PURPOSE

A case of autoimmune hemolytic anemia (AIHA) after treatment with a Chinese herbal preparation is reported.

SUMMARY

A 29-year-old woman was admitted to the hospital with the primary complaints of jaundice, tea-colored urine, and fatigue lasting 10 days. Thirteen days prior, she went to a local private clinic seeking treatment for mild stomach pain and general malaise and was given weidean tablets. She took four tablets of weidean, a Chinese herbal preparation, orally three times daily for 2 days. After 2 days, she experienced fatigue, dizziness, and chest distress and subsequently discontinued treatment. Upon examination, she exhibited mild scleral and mucosal icterus. Her conjunctivas were pale, and her skin was slightly jaundiced. Preliminary laboratory tests found a low hemoglobin level and an elevated reticulocyte count. Biochemical tests showed an elevated total serum bilirubin concentration with indirect hyperbilirubinemia. Coombs' test results were positive for immunoglobulin G but negative for C3. All other test results were normal. The patient was diagnosed with AIHA secondary to weidean use, and she was treated promptly with oral prednisone, i.v. cimetidine, and oral sodium bicarbonate tablets. Seven days later, she showed clinical improvement. Her hemoglobin level rapidly increased to above 100 g/L, with a corresponding decrease in her reticulocyte count and serum bilirubin value over the next 8 days. She was discharged 15 days after admission and was asymptomatic at a three-week follow-up visit.

CONCLUSION

Weidean, a formulation of Chinese medicinal herbs and other constituents, was associated with AIHA in a woman taking the remedy for gastritis.

Acute kidney injury associated with the use of traditional medicines

The use of traditional medicine is common worldwide, with rates of use of over 80% in some populations. Considering the large number of people using traditional remedies throughout the world, it does seem that most do so without major adverse effects. Nevertheless, many folk medicines can cause kidney injury. Drug-induced nephrotoxicity reportedly contributes to up to 26% of cases of hospital-acquired acute kidney injury (AKI) and 18% of cases of community-acquired AKI globally, and folk remedies account for up to 35% of cases of AKI in the developing world. The kidney is highly susceptible to toxic insults because its intrinsic functions expose it to exceptionally high concentrations of any particular toxic substance. Clinical syndromes of nephrotoxicity can be defined according to the predominant regions of the kidney affected by the toxin, and reversibility of the injury is likely related to the severity and nature of the injury and also to the duration of toxin exposure. In countries with well-developed health-care systems, a large proportion of patients with nephrotoxicity will recover at least some renal function with adequate supportive care and dialysis. Health-care practitioners in all countries should be aware of the high prevalence of the use of alternative therapies and should be proactive in obtaining this information from patients. In poorer countries, where large proportions of the population rely on traditional medicine, attempts should be made to integrate traditional healers into the health-care system.