Greater adherence to the Mediterranean diet has beneficial effects on the prevention of chronic diseases. In the current study, we investigated the association between the Mediterranean diet score (MDS) and the 6-year incidence of chronic kidney disease (CKD), conducted in the framework of the Tehran Lipid and Glucose Study with 1212 adults, aged 30-71 years. Dietary intake was assessed using a valid and reliable food-frequency questionnaire, and all subjects received scores between 0 and 8 points based on the traditional MDS. The components of the MDS were fruits and nuts, vegetables, legumes, cereals, fish, meat, dairy products and the monounsaturated to saturated fatty acid ratio. The odds ratio (OR) for the occurrence of CKD according to the quartiles of the MDS was assessed by multivariable logistic regression. The mean (s.d.) age of participants (51% male) at baseline was 43.5 (9.4) years. The median (25-75 interquartile range) of MDS for all subjects was 4 (3-5).The incidence of CKD was 19%. After adjustment for all potential confounding variables, individuals in the highest quartile of the MDS were 51% less likely to have CKD than those in the lowest quartile (OR=0.49; 95% confidence interval (CI): 0.30-0.82). Additionally, after further adjustment for baseline estimated glomerular filtration rate (GFR), the inverse association between the MDS and the 6-year incidence of CKD remained significant (OR=0.53; 95% CI: 0.31-0.91). Our findings demonstrate a significant inverse association between the MDS and the risk of incident CKD, indicating that adherence to the Mediterranean diet has favorable effects on the prevention of kidney dysfunction.Hypertension Research advance online publication, 11 August 2016; doi:10.1038/hr.2016.98.

Dietary protein restriction may improve determinants of CKD progression. However, the extent of improvement and effect of ketoanalogue supplementation are unclear. We conducted a prospective, randomized, controlled trial of safety and efficacy of ketoanalogue-supplemented vegetarian very low-protein diet (KD) compared with conventional low-protein diet (LPD). Primary end point was RRT initiation or>50% reduction in initial eGFR. Nondiabetic adults with stable eGFR<30 ml/min per 1.73 m(2), proteinuria<1 g/g urinary creatinine, good nutritional status, and good diet compliance entered a run-in phase on LPD. After 3 months, compliant patients were randomized to KD (0.3 g/kg vegetable proteins and 1 cps/5 kg ketoanalogues per day) or continue LPD (0.6 g/kg per day) for 15 months. Only 14% of screened patients patients were randomized, with no differences between groups. Adjusted numbers needed to treat (NNTs; 95% confidence interval) to avoid composite primary end point in intention to treat and per-protocol analyses in one patient were 4.4 (4.2 to 5.1) and 4.0 (3.9 to 4.4), respectively, for patients with eGFR<30 ml/min per 1.73 m(2). Adjusted NNT (95% confidence interval) to avoid dialysis was 22.4 (21.5 to 25.1) for patients with eGFR<30 ml/min per 1.73 m(2) but decreased to 2.7 (2.6 to 3.1) for patients with eGFR<20 ml/min per 1.73 m(2) in intention to treat analysis. Correction of metabolic abnormalities occurred only with KD. Compliance to diet was good, with no changes in nutritional parameters and no adverse reactions. Thus, this KD seems nutritionally safe and could defer dialysis initiation in some patients with CKD.

In December 2019, a coronavirus 2019 (COVID-19) disease outbreak occurred in Wuhan, Hubei Province, China, and rapidly spread to other areas worldwide. Although diffuse alveolar damage and acute respiratory failure were the main features, the involvement of other organs needs to be explored. Since information on kidney disease in patients with COVID-19 is limited, we determined the prevalence of acute kidney injury (AKI) in patients with COVID-19. Further, we evaluated the association between markers of abnormal kidney function and death in patients with COVID-19. This was a prospective cohort study of 701 patients with COVID-19 admitted in a tertiary teaching hospital that also encompassed three affiliates following this major outbreak in Wuhan in 2020 of whom 113 (16.1%) died in hospital. Median age of the patients was 63 years (interquartile range, 50-71), including 367 men and 334 women. On admission, 43.9% of patients had proteinuria and 26.7% had hematuria. The prevalence of elevated serum creatinine, elevated blood urea nitrogen and estimated glomerular filtration under 60 ml/min/1.73mwere 14.4, 13.1 and 13.1%, respectively. During the study period, AKI occurred in 5.1% patients. Kaplan-Meier analysis demonstrated that patients with kidney disease had a significantly higher risk for in-hospital death. Cox proportional hazard regression confirmed that elevated baseline serum creatinine (hazard ratio: 2.10, 95% confidence interval: 1.36-3.26), elevated baseline blood urea nitrogen (3.97, 2.57-6.14), AKI stage 1 (1.90, 0.76-4.76), stage 2 (3.51, 1.49-8.26), stage 3 (4.38, 2.31-8.31), proteinuria 1+ (1.80, 0.81-4.00), 2+∼3+ (4.84, 2.00-11.70), and hematuria 1+ (2.99, 1.39-6.42), 2+∼3+ (5.56,2.58- 12.01) were independent risk factors for in-hospital death after adjusting for age, sex, disease severity, comorbidity and leukocyte count. Thus, our findings show the prevalence of kidney disease on admission and thedevelopment of AKI during hospitalization in patients with COVID-19 is high and is associated with in-hospital mortality. Hence, clinicians should increase their awareness of kidney disease in patients with severe COVID-19.

PURPOSE OF REVIEW:Plant-based diets have been used with growing popularity for the treatment of a wide range of lifestyle-related diseases, including diabetes, hypertension, and obesity. With the reinvigoration of the conservative and dietary management of chronic kidney disease (CKD) and the use of low protein diets for secondary prevention of CKD to delay or prevent dialysis therapy, there is an increasing interest in the potential role of plant-based diets for these patients.

RECENT FINDINGS:Recently, a body of evidence related to the role of plant-based diet in preventing CKD has reemerged. Several observational studies have shown that red and processed meat have been associated with increased risk of CKD as well as faster progressing in those with preexisting CKD. In several substitution analyses, replacement of one serving of red and/or processed meat has been linked with sizable reductions in CKD risk as primary prevention. Although limited, experimental trials for the treatment of metabolic acidosis in CKD with fruits and vegetables show outcomes comparable to oral bicarbonate. The use of plant-based diets in CKD may have other benefits in the areas of hypertension, weight, hyperphosphatemia, reductions in hyperfiltration, and, possibly, mortality. The risk of potassium overload from plant-based diets appears overstated, mostly opinion-based, and not supported the evidence. Plant-based diets are generally well tolerated and provide adequate protein intake, including essential amino acids as long as the is correctly implemented.

SUMMARY:Plant-based diets should be recommended for both primary and secondary prevention of CKD. Concerns of hyperkalemia and protein inadequacy related to plant-based diets may be outdated and unsupported by the current body of literature. Healthcare providers in general medicine and nephrology can consider plant-based diets as an important tool for prevention and management of CKD.

The mechanisms of kidney diseases, such as acute kidney injury (AKI) and chronic kidney disease (CKD), have been intensively studied. Nonetheless, the morbidity and mortality of AKI and CKD increased in recent years. Recently, natural products have been increasingly recognized as an alternative source for treating renal diseases on account of the conventional experience and the multi-target characteristics. Ganoderma lucidum (G. lucidum, Lingzhi) has been used for centuries as nutraceuticals and alternative medicine to improve health and to treat numerous diseases. Benefiting from various biological activities, such as anti-oxidation, anti-inflammation, anti-tumor growth and metastasis, etc., G. lucidum has been proved to exhibit significant role in preventing and treating various kidney diseases. In this chapter, we review certain researches and provide comprehensive insights into the renoprotective effects of G. lucidum.

BACKGROUND:Sodium bicarbonate and ascorbic acid have been proposed to prevent contrast-induced nephropathy (CIN). The present study evaluated the effect of their combined use on CIN incidence.Methods and Results:We prospectively enrolled 429 patients with chronic kidney disease (CKD: baseline estimated glomerular filtration rate<60 mL/min/1.73 m(2)) prior to elective coronary catheterization. CIN was defined as absolute (≥0.5 mg/dL) or relative (≥25%) increase in serum creatinine within 72 h. In the saline hydration (n=218) and combined sodium bicarbonate+ascorbic acid (n=211) groups, a total of 1,500-2,500 mL 0.9% saline was given before and after the procedure. In addition, the combination group received 20 mEq sodium bicarbonate and 3 g ascorbic acid i.v. before the procedure, followed by 2 g ascorbic acid after the procedure and a further 2 g after 12 h. There were no significant differences between the basic characteristics and contrast volume in the 2 groups. CIN occurred in 19 patients (8.7%) in thesaline group, and in 6 patients (2.8%) in the combined treatment group (P=0.008).

CONCLUSIONS:Combined sodium bicarbonate and ascorbic acid could prevent CIN following catheterization in CKD patients.

Ozone therapy is an effective medical treatment for various diseases. A previous study has demonstrated its reno-protective effect in chronic kidney disease (CKD), but the mechanism involved is not completely known. This study produced the 5/6 nephrectomized CKD rat model and investigated whether the reno-protective effect of ozone therapy was achieved by its anti-inflammatory property through the modulation of the NLRP3 inflammasome. The results showed that ozone therapy at a low concentration improved renal function and ameliorated renal morphological injury in 5/6 nephrectomized rats. The expression of NLRP3, ASC, and caspase-1-p10 in the kidney of these rats was simultaneously lowered by ozone therapy. Moreover, renal inflammation caused by IL-1β was significantly alleviated by ozone therapy. The Pearson correlation analysis indicated that the protein level of IL-1β was positively correlated with renal injury scores. Taken together, these results indicated that ozone therapy might reduce sterile renal inflammation and slow down CKD progression through the modulation of the NLRP3 inflammasome in 5/6 nephrectomized rats.

BACKGROUND:Pregnancy in women with advanced CKD becoming increasingly common. However, experience with low-protein diets in CKD patients in pregnancy is still limited. Aim of this study is to review the results obtained over the last 15 years with moderately restricted low-protein diets in pregnant CKD women (combining: CKD stages 3-5, proteinuria: nephrotic at any time, or > =1 g/24 at start or referral; nephrotic in previous pregnancy). CKD patients on unrestricted diets were employed for comparison.

METHODS:

STUDY PERIOD:January, 2000 to September, 2015: 36 on-diet pregnancies (31 singleton deliveries, 3 twin deliveries, 1 pregnancy termination, 1 miscarriage); 47 controls (42 singleton deliveries, 5 miscarriages). The diet is basically vegan; since occasional milk and yoghurt are allowed, we defined it vegan-vegetarian; protein intake (0.6-0.8 g/Kg/day), keto-acid supplementation, protein-unrestricted meals (1-3/week) are prescribed according to CKD stage and nutritional status. Statistical analysis was performed as implemented on SPSS.

RESULTS:Patients and controls were similar (p: ns) at baseline with regard to age (33 vs 33.5), referral week (7 vs 9), kidney function (CKD 3-5: 48.4 % vs 64.3 %); prevalence of hypertension (51.6 % vs 40.5 %) and proteinuria>3 g/24 h (16.1 % vs 12.2 %). There were more diabetic nephropathies in on-diet patients (on diet: 31.0 % vs controls 5.3 %; p 0.007 (Fisher)) while lupus nephropathies were non-significantly higher in controls (on diet: 10.3 % vs controls 23.7 %; p 0.28 (Fisher)). The incidence of preterm delivery was similar (<37 weeks: on-diet singletons 77.4 %; controls: 71.4 %). The incidence of other adverse pregnancy related outcomes was non-significantly lower in on-diet patients (early preterm delivery: on diet: 32.3 % vs controls 35.7 %; birth-weight = <1.500 g: on diet: 9.7 % vs controls 23.8 %). None of the singletons in the on-diet series died, while two perinatal deaths occurred among the controls (p = 0.505). The incidence of small for gestational age (SGA<10th centile) and/or extremely preterm babies (<28th week) was significantly lower in singletons from on-diet mothers than in controls (on diet: 12.9 % vs controls: 33.3 %; p: 0.04 (Fisher)).

CONCLUSION:Moderate protein restriction in the context of a vegan-vegetarian supplemented diet is confirmed as a safe option in the management of pregnant CKD patients.

While dietary restriction of protein intake has long been proposed as a possible kidney-protective treatment, the effects of changes in the quality of ingested proteins on the prevalence and risk of progression of chronic kidney disease (CKD) have been scarcely studied; these two aspects are reviewed in the present article. The prevalence of hypertension, type 2 diabetes and metabolic syndrome, which are the main causes of CKD in Western countries, is lower in vegetarian populations. Moreover, there is a negative relationship between several components of plant-based diets and numerous factors related to CKD progression such as uraemic toxins, inflammation, oxidative stress, metabolic acidosis, phosphate load and insulin resistance. In fact, results from different studies seem to confirm a kidney-protective effect of plant-based diets in the primary prevention of CKD and the secondary prevention of CKD progression. Various studies have determined the nutritional safety of plant-based diets in CKD patients, despite the combination of a more or less severe dietary protein restriction. As observed in the healthy population, this dietary pattern is associated with a reduced risk of all-cause mortality in CKD patients. We propose that plant-based diets should be included as part of the clinical recommendations for both the prevention and management of CKD.