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

Aristolochic Acid and Immunotherapy for Urothelial Carcinoma: Directions for unmet Needs

Urothelial carcinoma of the bladder (UCB) and upper tracts (UTUC) used to share management with similar principles. However, their genetic and epigenetic differences along with different responses to immunotherapy were recently identified, which are reminiscent of their distinct etiologies. Different from the variety of environmental factors relating to UCB, UTUC is best known for its close relationship with exposure to aristolochic acid (AA). AA is believed to cause its carcinogenicity through forming DNA adducts of deoxyadenosine-aristolactam, as well as A:T → T:A transversions in the TP53 tumor suppressor gene. Since recent findings suggested that cancers with higher somatic mutations are associated with better treatment responses upon immune checkpoint blockade, UTUC and AA-related biomarkers reasonably serve as good candidates, as well as a potential prognostic predictor for the flourishing immunotherapy. This review covers the current state of the literature on the clinical response of UTUC and UCB receiving immunotherapy and points out directions for refinement regarding patient selection.

Rejuvenation: Turning back the clock of aging kidney

Aging is inevitable in life. It is defined as impaired adaptive capacity to environmental or internal stresses with growing rates of disease and death. Aging is also an important risk factor for various kidney diseases such as acute kidney injury and chronic kidney disease. Patients older than 65 years have nearly 28% risk of failing recovery of kidney function when suffering from acute kidney injury. It is reported that more than a third of population aged 65 years and older have chronic kidney disease in Taiwan, and the occurrence of multiple age-related disorders is predicted to increase in parallel. Renal aging is a complex, multifactorial process characterized by many anatomical and functional changes. Several factors are involved in renal aging, such as loss of telomeres, cell cycle arrest, chronic inflammation, activation of renin-angiotensin system, decreased klotho expression, and development of tertiary lymphoid tissues. These changes can also be observed in many other different types of renal injury. Recent studies suggested that young blood may rejuvenate aged organs, including the kidneys. In order to develop new therapeutic strategies for renal aging, the mechanisms underlying renal aging and by which young blood can halt or reverse aging process warrants further study.

Systematic Overview of Aristolochic Acids: Nephrotoxicity, Carcinogenicity, and Underlying Mechanisms

Aristolochic acids (AAs) are a group of toxins commonly present in the plants of genus Aristolochia and Asarum, which are spread all over the world. Since the 1990s, AA-induced nephropathy (AAN) and upper tract urothelial carcinoma (UTUC) have been reported in many countries. The underlying mechanisms of AAN and AA-induced UTUC have been extensively investigated. AA-derived DNA adducts are recognized as specific biomarkers of AA exposure, and a mutational signature predominantly characterized by A→T transversions has been detected in AA-induced UTUC tumor tissues. In addition, various enzymes and organic anion transporters are involved in AA-induced adverse reactions. The progressive lesions and mutational events initiated by AAs are irreversible, and no effective therapeutic regimen for AAN and AA-induced UTUC has been established until now. Because of several warnings on the toxic effects of AAs by the US Food and Drug Administration and the regulatory authorities of some other countries, the sale and use of AA-containing products have been banned or restricted in most countries. However, AA-related adverse events still occur, especially in the Asian and Balkan regions. Therefore, the use of AA-containing herbal remedies and the consumption of food contaminated by AAs still carry high risk. More strict precautions should be taken to protect the public from AA exposure.

Chronic Kidney Disease is Associated With Upper Tract Urothelial Carcinoma: A Nationwide Population-Based Cohort Study in Taiwan

Increased urinary tract malignancy has been reported in end-stage renal disease (ESRD). However, little is known about chronic kidney disease (CKD). This study is designed to explore the association between CKD and upper tract urothelial carcinoma (UTUC).Using Taiwan's Longitudinal Health Insurance Database, we studied CKD patients between January 2000 and December 2011. The non-CKD controls were selected at a ratio of 4:1 and frequency matched by gender, age group, and index date. We used the chi-square test and t test to analyze the sociodemographic information and comorbidities. Cox regression analysis was used to calculate the hazard ratio (HR) and 95% confidence interval (CI).The selected cases included 45,321 CKD cases and 181,284 controls. A significantly higher incidence of UTUC was noted in the CKD group (0.22% vs 0.07%, P < 0.001). In univariate analysis, CKD, female gender, age, hypertension, hematuria, repeated urinary tract infection, bladder cancer, and ESRD were all associated with UTUC. In multivariate analysis, only CKD, female gender, age, hematuria, bladder cancer, and ESRD were significantly associated. The HR for CKD was 1.63 (95% CI: 1.26-2.13). Females had a higher HR of 1.38 (95% CI: 1.11-1.71). After excluding those patients who progressed to dialysis or kidney transplantation, the risk for CKD was still high, with an HR of 1.72 (95% CI: 1.33-2.33).CKD is a significant factor associated with UTUC. We should pay attention to the possibility of UTUC for CKD patients before they progress to ESRD.

Andrographolide induced acute kidney injury: analysis of 26 cases reported in Chinese Literature

AIM

Some Chinese herbs have been known for their kidney toxicity. Andrographolide, the primary component of a traditional medicinal herb, Andrographis paniculata, is widely used in China for the treatment of upper and lower respiratory tract infection, and dysentery etc. The aim of the study was to identify and summarize any case of kidney injury attributed to its use in the Chinese literature.

METHODS

A systemic analysis of the Chinese literature from January 1978 to August 2013 was conducted of case reports of andrographolide induced acute kidney injury (AKI).

RESULTS

We identified 26 cases of andrographolide induced AKI (22 males and four females), with an average age of 31.3 years (range: 21 months to 47 years). 100-750 mg (58% 500 mg) of andrographolide was administered in 100-500 mL 5% glucose solution or normal saline by intravenous drip once a day. The adverse event appeared after one to six doses (19 [73.1%] patients got only one dose; cumulative dose 690 ± 670 mg) of andrographolide was given, or 0-96 h (median 1 h) after andrographolide was given. The symptoms included flank pain in 23 cases (88.5%), decreased urine volume in five cases (19.2%), and nausea or vomiting in six cases (23.1%). Laboratory tests showed maximum creatinine 352.8 ± 184.1 (158-889) μmol/L and blood urea nitrogen 12.1 ± 7.6 (4.0-40.6) mmol/L. Urine analysis showed proteinuria in 10 (38.5%) cases and occult blood in eight (30.8%) cases. Kidney biopsy was carried out in two cases and both revealed acute tubular necrosis. Management of this adverse event included withdrawal of the culprit drug, conservative therapy, and renal replacement therapy (six cases, 23.1%). All the patients recovered and were discharged with a normal or close to normal serum creatinine. Their average length of hospital stay was 12.1 ± 4.8 days.

CONCLUSIONS

Acute kidney injury may occur shortly after intravenous infusion of andrographolide, with symptoms including flank pain, decreased urine output, and nausea or vomiting. The pathological change might be acute tubular necrosis. Renal replacement therapy may be needed in some patients and with a good recovery rate. The mechanisms of andrographolide induced AKI need to be further studied.

Renoprotective effect of combining pentoxifylline with angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker in advanced chronic kidney disease

BACKGROUND/PURPOSE

Several studies have shown the renoprotective effects of pentoxifylline in the treatment of chronic kidney disease (CKD). This study was conducted to examine whether there was an increased benefit of including pentoxifylline with angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) in the treatment of CKD.

METHODS

A single-center retrospective analysis was conducted. A total of 661 Stage 3B-5 CKD patients who received ACEI or ARB treatment were recruited. The patients were divided into the pentoxifylline use group and the no pentoxifylline group. Renal survival analysis of the two groups was compared. Subgroup analysis was performed by dividing the patients into lower [urine protein to creatinine ratio (UPCR)<1 g/g] and higher (UPCR ≥ 1 g/g) proteinuria subgroups.

RESULTS

There was no between-groups difference regarding mortality and cardiovascular events. Addition of pentoxifylline showed a better renal outcome (p = 0.03). The protective effect of add-on pentoxifylline was demonstrated in the higher proteinuria subgroup (p = 0.005). In the multivariate Cox regression model, pentoxifylline use also showed a better renal outcome [hazard ratio (HR): 0.705; 95% confidence interval (CI): 0.498-0.997; p = 0.048]. This effect was more prominent in the higher proteinuria subgroup (HR: 0.602; 95% CI: 0.413-0.877; p = 0.008).

CONCLUSION

In the advanced stages of CKD, patients treated with a combination of pentoxifylline and ACEI or ARB had a better renal outcome than those treated with ACEI or ARB alone. This effect was more prominent in the higher proteinuria subgroup. More large randomized control trials are needed to provide concrete evidence of the add-on effect of pentoxifylline.

Stem cells and kidney regeneration

Kidney disease is an escalating burden all over the world. In addition to preventing kidney injury, regenerating damaged renal tissue is as important as to retard the progression of chronic kidney disease to end stage renal disease. Although the kidney is a delicate organ and has only limited regenerative capacity compared to the other organs, an increasing understanding of renal development and renal reprogramming has kindled the prospects of regenerative options for kidney disease. Here, we will review the advances in the kidney regeneration including the manipulation of renal tubular cells, fibroblasts, endothelial cells, and macrophages in renal disease. Several types of stem cells, such as bone marrow-derived cells, adipocyte-derived mesenchymal stem cells, embryonic stem cells, and induced pluripotent stem cells are also applied for renal regeneration. Endogenous or lineage reprogrammed renal progenitor cells represent an attractive possibility for differentiation into multiple renal cell types. Angiogenesis can ameliorate hypoxia and renal fibrosis. Based on these studies and knowledge, we hope to innovate more reliable pharmacological or biotechnical methods for kidney regeneration medicine.

Therapeutic use of traditional Chinese herbal medications for chronic kidney diseases

Traditional Chinese herbal medications (TCHM) are frequently used in conjunction with western pharmacotherapy for treatment of chronic kidney diseases (CKD) in China and many other Asian countries. The practice of traditional Chinese medicine is guided by cumulative empiric experience. Recent in vitro and animal studies have confirmed the biological activity and therapeutic effects of several TCHM in CKD. However, the level of evidence supporting TCHM is limited to small, non-randomized trials. Due to variations in the prescription pattern of TCHM and the need for frequent dosage adjustment, which are inherent to the practice of traditional Chinese medicine, it has been challenging to design and implement large randomized clinical trials of TCHM. Several TCHM are associated with significant adverse effects, including nephrotoxicity. However, reporting of adverse effects associated with TCHM has been inadequate. To fully realize the therapeutic use of TCHM in CKD we need molecular studies to identify active ingredients of TCHM and their mechanism of action, rigorous pharmacologic studies to determine the safety and meet regulatory standards required for clinical therapeutic agents, and well-designed clinical trials to provide evidence-based support of their safety and efficacy.