Influence of bowel habits on gut-derived toxins in peritoneal dialysis patients.
BACKGROUND
Gut-derived uremic toxins have been associated with adverse outcomes in chronic kidney disease (CKD). Alterations in bowel habits, including constipation, seem to play an additional role in uremic toxicity. The aim of this study is to investigate the association of bowel habits with gut-derived uremic toxins and intestinal permeability in patients on automated peritoneal dialysis (APD).


METHODS
This cross-sectional study enrolled 58 APD patients (age 52.5 ± 15.1 years; dialysis vintage 14.1 (6.0-36.5) months). Constipation was defined according to the Rome IV criteria. Bowel habits were assessed by the Bristol Stool Scale (BSS < 3 characterized by hard consistency of stools and/or low frequency of evacuation, a surrogate of slow intestinal transit time, and BSS ≥ 3, defining regular bowel habit). The total and free serum concentration of p-cresyl sulfate (PCS), indoxyl sulfate (IS) and indole-3-acetic acid (IAA) were dosed by high-performance liquid chromatography. Lipopolysaccharide (LPS) and zonulin were assessed by ELISA and D(-)-lactate by colorimetric method. Dietary intake was assessed by the 3-day food records.


RESULTS
No differences were observed in clinical, demographic, and dietary characteristics between constipated (n = 30) and non-constipated (n = 28) groups. A trend for higher total PCS (p = 0.07) and free PCS (p = 0.06) was found in constipated patients. Patients with BSS < 3 (n = 11) exhibited significantly higher levels of total and free PCS (p < 0.01) and total IAA (p = 0.04). Conversely, No difference was found in IS levels. Except for a lower serum level of D(-)-lactate in patients with BSS < 3 (p = 0.01), zonulin and LPS levels were not different.


CONCLUSIONS
Disturbed bowel habits, mainly characterized by slow transit time, may play a role in the accumulation of uremic toxins, particularly PCS, in patients on automatized peritoneal dialysis.
['Pereira|Natalia Barros Ferreira|NBF|http://orcid.org/0000-0001-6214-8084', 'Ramos|Christiane Ishikawa|CI|http://orcid.org/0000-0003-2382-0362', 'de Andrade|Laila Santos|LS|http://orcid.org/0000-0001-7763-4202', 'Teixeira|Renata Rodrigues|RR|http://orcid.org/0000-0001-9378-3275', 'Nakao|Lia Sumie|LS|http://orcid.org/0000-0001-9647-6350', 'Rodrigues|Silvia Daniéle|SD|', 'de Lima|Jordana Dinorá|JD|', 'Dalboni|Maria Aparecida|MA|', 'Cuppari|Lilian|L|http://orcid.org/0000-0002-5927-9179']
D003408:Cresols D003430:Cross-Sectional Studies D006184:Habits D006801:Humans D007200:Indican D008875:Middle Aged D010530:Peritoneal Dialysis D051436:Renal Insufficiency, Chronic D013463:Sulfuric Acid Esters
Uremic toxins Chronic kidney disease Constipation Inflammation