Filomena Panza2, Diletta Duranti1, Ralli Chiara2, Matteo Basile1, Marco Bagnati1, Giorgio Bellomo1 and Ennio Duranti2*
1Department of Pathology and Clinical Laboratories AUO Novara
2UOC Nephrology and Dialysis Unit, Hospital of Arezzo
Received: 14 March, 2017; Accepted: 29 April, 2017; Published: 03 May, 2017
Ennio Duranti, UOC Nephrology and Dialysis Unit, Hospital of Arezzo, Italy, E-mail:
Panza F, Duranti D, Chiara R, Basile M, Bagnati M, et al. (2017) Short-Term Effects of Pre/Probiotics on P-Cresol and Indoxyl-Sulphate Serum Concentrations During the Various Stages of Chronic Kidney Disease. Arch Renal Dis Manag 3(1): 001-005. DOI: 10.17352/2455-5495.000017
© 2017 Panza F, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Background: The uremic syndrome is provoked by a progressive number of compounds that are normally excreted by kidneys in healthy individuals. Indoxylsulphate (IXS) and p-cresylsulphate (PCS), have been found increased in subjects with end stage renal disease (ESRD) creating great harm to biological systems; these uremic toxins come from the intestinal bacterial fermentation of the proteins. The aim of our study is to evaluate the short-term effects after an administration of pre / probiotics in CKD patients, regarding the production and then the serum concentrations of free IXS and PCS (i.e. non-protein bound fraction) and total IXS and PCS ( i.e. sum of unbound and protein bound fraction).
Methods: In our study , 26 patients with CKD stage 2-5 associated with hypertension and / or diabetes mellitus type 2 were enrolled, and administered with 2 g/day dose of pre-probiotics for four months: mixed oligofructose (prebiotic component) + Lactobacillus acidophilus and Bifidobacterium longum (probiotic component). In all patients, at the beginning of the study, kidney function tests, glucose metabolism, PTH and blood uric acid were evaluated. Free and total PCS and IXS were also measured. 20 control subjects with normal renal function were considered in relation to the same parameters.
After 4 months 19 patients were re-evaluated in relation to the same parameters. Statistical differences were studied using the Student-t paired and unpaired tests.
Results: The baseline values of IXS and PCS of the 26 patients were significantly higher compared with the normal subjects and importantly increased with the transition to the higher stage of CKD. The values in stage 2 - 3 CKD were significantly lower in respect to stage 4 – 5 CKD. Higher mean values of IXS and PCS in 12 diabetic subjects were highlighted, although not statistically significant compared to 14 hypertensive non-diabetic patients.
The data after the use of pre - probiotics in 19 patients that completed the treatment protocol (5 patients were out of the study for non-compliance of the processing and 2 patients for dialysis entrance), showed increased concentrations of free and total IXS and PCS. Considering renal function, the use of pre - probiotics increased the concentration of free and total PCS and IXS in all conditions, while remaining significantly higher in patients at stage 4-5 rather than in the ones at the stage 2-3. The use of pre - probiotics increased the IXS and PCS serum concentrations, remaining significantly higher in diabetics rather than in hypertensive patients. In all periods, both baseline and after the uptake of pre-probiotics, the other measured parameters didn’t change except serum PTH that decreased significantly and Calcium increased even if not significantly
Conclusions: In conclusion IXS and PCS can be considered as kidney function markers as well as have systemic toxic effects. Diabetes seems to increase the concentration of the two metabolites. The use of pre-probiotics should be started in the early stages of kidney failure and certainly for periods longer than four months. Pre-probiotics could aid in preventing renal osteodystrophy.
The uremic syndrome is provoked by a progressive number of compounds that are normally excreted by kidneys in healthy individuals. At least 90 compounds, often called uremic toxins, like indoxylsulphate (IXS) and p-cresylsulphate (PCS), have been found increased in subjects with ESRD creating great harm to biological systems ; these uremic toxins come from the intestinal bacterial fermentation  of the proteins. These solutes are considered not only biomarkers of renal function, but according to some authors they contribute to the development of kidney disease. The accumulation of these compounds has a negative impact on many body functions, especially on the cardiovascular system, as recently proved by several authors who underline the association among serum PCS, cases of general mortality and cardiovascular mortality either in chronic kidney disease (CKD) or in its final stage [3-5]. In addition, in a study of Schepers et al., it has been shown that PCS stimulates the basic leukocyte activity with pro-inflammatory effects, inhibiting the activated leukocyte function and inducing endothelial disorder , a condition that could induce cardiovascular events. PCS, a phenol 108 Da MW, is a terminal product of protein catabolism, produced by intestinal bacteria that metabolize tyrosine and phenylalanine [7,8].
As regards IXS it is metabolized by the liver from the indol, which is produced by the intestinal flora as a metabolite of tryptophan. IXS causes an endothelial disorder of the uremia, promoting the proliferation of smooth muscle cells through the activation of growth factors derived from platelets and inducing a significant production of free radicals by endotelail cells. IXS appears to have a clinically important role in aortic stiffness and vascular calcification [9-11].
PCS and IXS both come from bacterial fermentation of the proteins in the large intestine: the colonic microbiota degrades tryptophan to indole. Therefore in renal failure conditions, the altered intestinal bacterial metabolism changes serum concentrations of IXS and PCS, so we wonder wether it is possible to induce a decrease of their serum concentrations. At this regard it was found that the intake of prebiotic inulin, enriched with oligofructose, could significantly reduce serum concentrations of PCS and IXS ; therefore clinical studies investigating the role of prebiotics and / or probiotics in CKD patients, would be useful in order to evaluate the possible positive impact on the evolution of chronic renal failure prevention. The aim of our study is to evaluate the short-term effects after an administration of pre / probiotics in CKD patients, regarding the production and then the serum concentrations of free IXS and PCS (i.e. non-protein bound fraction) and total IXS and PCS (i.e. sum of unbound and protein bound fraction).
Materials and Methods
In our study , 26 patients with CKD stage 2-5 associated with hypertension and / or diabetes mellitus type 2 (Table 1) were enrolled, and administered with 2 g/day dose of pre-probiotics for four months: mixed oligofructose (prebiotic component) + Lactobacillus acidophilus and Bifidobacterium longum (probiotic component). In all patients, at the beginning of the study, kidney function tests, glucose metabolism, PTH and blood uric acid were evaluated. Free and total PCS and IXS were also measured. The two metabolites were analyzed in fresh or frozen serum sample (in fact the stability of the compounds allows the two conditions). The method involves the denaturation and precipitation of serum total proteins for the separation of the supernatant, on which the total PCS and IXS will be measured (sum of the protein bound fraction and the unbound fraction). The free fraction of these metabolites is achieved by centrifugal filtration in order to remove the binder’s proteins. The dosage is performed by HPLC / MSMS using PCS-D4 as internal standard. At the same time 20 control subjects with normal renal function were considered in relation to the same parameters (Table 1).
After 4 months of daily intake of pre-probiotics, 19 patients were re-evaluated in relation to the same parameters. Statistical differences were studied using the Student-t paired and unpaired tests.
The baseline values of free and total IXS and PCS of the 26 patients were significantly higher compared with the 20 normal subjects (Table 1). Serum concentrations of both metabolites importantly increased with reduced renal function and with the transition to the higher stage of CKD (Figure 1). The values of both the metabolites, free and total, in stage 2 - 3 CKD were significantly lower, although higher than normal subjects, in respect to stage 4 – 5 CKD in which increased by over 100% (Figure 1). Within the group of 26 patients, higher mean values of IXS and PCS in 12 diabetic subjects were highlighted, although not statistically significant (except for the free PCS that was significantly higher, P <0.02), compared to 14 hypertensive non-diabetic patients (Table 2).
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