Uremia and chronic kidney disease: The role of the gut microflora and therapies with pro‐ and prebiotics

Uremia is an illness that accompanies kidney failure and chronic kidney disease (CKD). Uremic illness is considered to be due largely to the accumulation of organic waste products that are normally cleared by the kidneys. However, uremic retention solutes are generated in part in the gastrointestinal tract (GIT), with the gut microbiota and the ensuing micro‐biometabolome playing a significant role in the proliferation of uremic retention solutes. Toxins generated in, or introduced into the body via the intestine, such as advanced glycation end products, phenols, and indoles, all may contribute to the pathogenesis of CKD. Hence, it is biologically plausible, but not well recognized, that an important participant in the toxic load that contributes to CKD originates in the GIT. The microbiota that colonize the GIT perform a number of functions that include regulating the normal development and function of the mucosal barriers; assisting with maturation of immunological tissues, which in turn promotes immunological tolerance to antigens from foods, the environment, or potentially pathogenic organisms; controlling nutrient uptake and metabolism; and preventing propagation of pathogenic micro‐organisms. Here, we develop a hypothesis that probiotics and prebiotics have a therapeutic role in maintaining a metabolically balanced GIT, and reducing progression of CKD and associated uremia.     

肠道微生态与慢性肾脏疾病研究进展

慢性肾脏疾病是一种进行性发展的慢性疾病,近年来其患病率逐步升高。除临床药物治疗外,科学家正从营养学、食品科学等不同领域探求一种更加安全可靠、成本低、毒副作用小的治疗方式。诸多研究表明,肠道微生态与肾脏关系密切、相互影响,针对调节肠道微生态治疗慢性肾脏疾病的研究为减缓慢性肾脏疾病发展提供了新思路。因此,该文对慢性肾脏疾病与肠道微生态间的相互联系,以及通过调节肠道微生态治疗慢性肾脏疾病的研究现状进行综述。     

海参磷脂型二十碳五烯酸对链脲佐菌素诱导的糖尿病大鼠肾脏功能改善作用的研究

目的:研究海参磷脂型二十碳五烯酸（Eicosapentaenoic Acid Phosphatidy lcholine,EPA-PC）对链脲佐菌素（Streptozocin,STZ）诱导的糖尿病大鼠肾脏功能的改善作用。方法:通过腹腔注射STZ建立糖尿病大鼠模型,经不同剂量海参EPA-PC（25和75mg/kg,以EPA含量计）灌胃8w。实验结束后,分别检测大鼠空腹血糖、口服葡萄糖耐量、肾脏指数、24h尿量、血清尿素氮（BUN）、尿总蛋白、白蛋白（mAlb）、尿酸（UA）含量及β-N乙酰葡萄糖苷酶（NAG）活性。结果:海参EPA-PC可显著改善糖尿病大鼠的口服葡萄糖耐量（p<0.05）,降低糖尿病大鼠的肾脏指数（p<0.01）、24h尿量、血清BUN、尿总蛋白、mAlb、UA含量及NAG活性（p<0.01）。结论:海参EPA-PC对糖尿病大鼠的肾脏功能具有较好的改善作用。      

Chemopreventive effect of dietary curcumin on inflammation‐induced colorectal carcinogenesis in mice

Scope: Curcumin is a polyphenol with a variety of pharmacologic effects. We evaluate the effect of dietary curcumin on the severity of repeated colitis‐associated colorectal cancer. Methods and results: Six‐week‐old C57BL/6 mice were randomized into two dietary groups: standard diet and curcumin at 0.6% diet. The mice were exposed to 15 cycles of 0.7% dextran sodium sulphate for 1 week followed by distilled water for 10 days. After curcumin diet, the disease activity index presented a statistical reduction in the last cycles, macroscopic tumors were not seen and the microscopic study showed minor neoplasic lesions with respect to standard diet‐group. β‐Catenin translocation to the cytoplasm and/or nucleus was observed in the tumor tissue, but this translocation and its intensity were significantly minor in the curcumin diet‐DSS animals. Cytokines as tumor necrosis factor‐α and IFN‐γ were significantly diminished in DSS‐animals fed with curcumin. Conversely, non‐modification of p53 expression was observed and cyclo‐oxygenase‐2 and inducible nitric oxide synthase were significantly reduced in the curcumin diet‐DSS group. Conclusion: We demonstrate the protective/preventive effect of curcumin in the progression of colorectal cancer associated to colitis, which was correlated with a lowered immunoreactivity of ß‐catenin, a non‐modification of p53 expression, a reduction of proinflammatory cytokine levels and a decrease of inflammatory protein overexpression.     

Storage and ultraviolet‐induced tissue stress effects on fresh‐cut pineapple

The effect of UV‐induced stress on the volatile aroma compounds in cut pineapple was compared with that of storage at 4 °C for 24 h. Eighteen volatile compounds were identified by solid‐phase microextraction (SPME) in fresh‐cut pineapple. Methyl‐2‐methylbutanoate, methyl hexanoate, methyl 5‐hexenoate, ethyl hexanoate and ethyl 5‐hexenoate were the major aroma compounds. Storage at 4 °C for 24 h, and exposure of cut fruit to UV radiation for 15 min caused a considerable decrease in the concentration of esters and increase in the relative amount of copaene. This sesquiterpene, when added to crushed cantaloupe melon (0.1 mg g^?1), inhibited microbial growth in the fruit over a period of 24 h at 20 °C. Cis‐ and trans‐ocimene were present in the fruit but their production was not photo‐induced by UV irradiation. Ocimene, however, was a potent antimicrobial agent that killed microorganisms when added to the crushed fruit and stored at 20 °C for 24 h. The results indicate that sesquiterpene phytoalexins could contribute to the defense mechanism in wounded pineapple tissue. Published in 2004 for SCI by John Wiley & Sons, Ltd.     

In vitro and in vivo protective effects of gingenosides on acute renal injury induced by cantharidin

Ginsenosides are major active constituent of Panax ginseng which is a popularly used functional food or drug in several Asian countries. The effects of ginsenosides on the renal dysfunction and injury caused by cantharidin were investigated in vitro and in vivo. Ginsenosides inhibited the cytotoxicity in rat normal kidney NRK cell induced by cantharidin. Cantharidin caused NRK cell apoptosis accompanied with decreasing bcl-2 expression. Pretreatment of ginsenosides reduced apoptosis rate and increased bcl-2 expression. In experimental rats, administration of cantharidin (0.14 mg/kg) for 15 days induced renal damage, which was evident from significantly increased levels of serum creatinine, urine protein and urea nitrogen. Pretreatment of ginsenosides reduced the increases of serum creatinine, urine protein, urea nitrogen and histological change in rats. These findings provide the evidence that ginsenosides might be useful in enhancing the tolerance of the kidney against renal injury associated with cantharidin.     

Distinctive effects of plant protein sources on renal disease progression and associated cardiac hypertrophy in experimental kidney disease

Scope : Dietary soy protein reduces renal disease progression in a number of renal diseases, suggesting that plant compared with animal proteins may be renoprotective. The inclusion of other plant protein sources could enhance compliance of intervention diets, but the effects of other plant protein sources are not known. Methods and results : Weanling Han:SPRD‐cy rats with experimental polycystic kidney disease were given hemp‐, pea‐ and soy protein‐based diets compared with the standard AIN 93G diet with casein as the protein source. Kidneys from diseased rats given diets which contained soy or hemp protein compared with casein‐based diets were less enlarged, had lower fluid content, smaller cyst volumes, less fibrosis, lower chemokine receptor 2 (CCR2) levels and normalized serum creatinine levels. Soy and hemp protein diets also normalized heart size, which was enlarged in diseased compared with normal rats consuming casein. Kidneys from diseased rats given pea protein compared with casein were more enlarged and had higher fluid content and cyst volumes, despite growing better and having lower serum creatinine and renal chemokine receptor 2 levels, and similar levels of renal fibrosis. Conclusion : Not all plant proteins are equally protective in experimental kidney disease and associated cardiac hypertrophy.