Circulating Oxalate Levels in Short Bowel Syndrome as a Severity Marker of CKD.

Introduction: Patients with short bowel syndrome (SBS) may exhibit enteric hyperoxaluria (EH), and the prevalence of oxalate nephropathy in SBS is likely underestimated. Plasma oxalate (POx) is a surrogate of systemic oxalate deposition and, consequently, may increase the risk of developing chronic kidney disease (CKD). The main objective of this study was to explore the distribution of POx levels in patients with SBS. Methods: Patients followed for SBS were recruited prospectively in the OXAGO study (NCT04119765) to assess POx during their annual renal follow-up including iohexol clearance. The inclusion criteria were age ≥18 years, and SBS type 2 and type 3 for more than 6 months. Results: A total of 47 patients were included but only 45 patients has a measured POx (55% males, 80% SBS type 2, 66% parenteral nutrition, 61% kidney stone history). POx levels were 6.8 ± 4.4 µmol/l, 29% of patients had POx ≥5 µmol/l. In the whole cohort, mean urinary oxalate (UOx) was 648±415 and 54% were >500 µmol/24h. In the group of patients with high POx levels (HPO), 24-hour urine oxalate was significantly higher than in the group with normal POx levels (NPO) (919 ± 566 vs. 526 ± 257 µmol/l; P = 0.003). Glomerular filtration rate (GFR) was 66 ± 22 ml/min per 1.73 m2, and 91% had CKD. GFR was significantly lower in the HPO than in the NPO group (49 ± 23 vs. 73 ± 18 ml/min per 1.73 m2; P = 0.0005. Conclusion: Patients with SBS can display increased POx levels even with GFR >30 ml/min per 1.73 m2. POx may be an interesting biomarker to assess the severity of EH.

Evolution of renal function in patients with severe intestinal failure on home parenteral nutrition.

BACKGROUND: Kidney disease is a frequent but underestimated complication in patients suffering from intestinal failure (IF) treated by long-term home parenteral nutrition (HPN). The evolution in glomerular filtration rate (GFR) over time is poorly characterized. The current equations for estimating GFR have limited precision. No study has specifically investigated the reliability of recent creatinine-based estimated GFR (eGFR) equations in this population. The aim of this study was to evaluate the renal function decline under home parenteral nutrition (HPN) with a gold standard method and compare the performances of routinely used eGFR equations. METHODS: Forty patients with HPN and two or more GFR measurements were retrospectively studied. The renal function decline was calculated by the slope drawn between the successive measured GFRs (mGFRs). The performances of the Modification of Diet in Renal Disease, Chronic Kidney Disease Epidemiology Collaboration, full age spectrum and revised Lund-Malmö equations were compared with reference methods (inulin or iohexol clearance). RESULTS: The mean mGFR was 78 ± 28 mL/min/1.73 m2. The annual decline of mGFR was -1.9 mL/min/1.73 m2/year. No predisposing factor was identified to predict impairment in renal function. eGFR formulas grossly overestimated mGFR and had a low level of accuracy. CONCLUSIONS: Patients with IF are at significant risk for impaired renal function. In this population, the tested eGFR equations were inaccurate. However, monitoring kidney function with mGFR remains important in these patients, as their GFR regularly declines and no specific risk factor has yet been identified.

Vitamin C in Home Parenteral Nutrition: A Need for Monitoring.

To date, there are no recommendations about screening plasma vitamin C concentration and adjust its supplementation in patients on long-term home parenteral nutrition (HPN). The aim of this study was to evaluate vitamin C status and determine if a commercial multivitamin preparation (CMVP) containing 125 mg of vitamin C is sufficient in stable patients on HPN. All clinically stable patients receiving HPN or an intravenous fluid infusion at least two times per week for at least 6 months, hospitalized for nutritional assessment, were retrospectively included, for a total of 186 patients. We found that 29% of the patients had vitamin C insufficiency (i.e., <25 µmol/L). In univariate analysis, C-reactive protein (CRP) (p = 0.002) and intake of only 125 mg of vitamin C (p = 0.001) were negatively associated with vitamin C levels, and duration of follow-up in our referral center (p = 0.009) was positively associated with vitamin C levels. In multivariate analysis, only CRP (p = 0.001) and intake of 125 mg of vitamin C (p < 0.0001) were independently associated with low plasma vitamin C concentration. Patients receiving only CMVP with a low plasma vitamin C level significantly received personal compounded HPN (p = 0.008) and presented an inflammatory syndrome (p = 0.002). Vitamin C insufficiency is frequent in individuals undergoing home parenteral nutrition; therefore, there is a need to monitor plasma vitamin C levels, especially in patients on HPN with an inflammatory syndrome and only on CMVP.

Effect of bile acid supplementation on endogenous lipid synthesis in patients with short bowel syndrome: A pilot study.

BACKGROUND & AIMS: Short bowel syndrome patients (SBS) receiving parenteral nutrition (PN) often have dyslipidaemia and can develop intestinal failure-associated liver disease (IFALD). These patients demonstrate increased cholesterol synthesis and hepatic lipogenesis. These lipid disturbances may be due to a decreased concentration of the bile acid pool or malabsorption. The aim of this pilot study was to evaluate the effect of bile acid administration on lipid synthesis in patients with SBS. METHODS: The 24 h fractional synthesis rate (FSR) of cholesterol and triglycerides was measured by the isotopic method (deuterated water) before and after 4 months of ursodeoxycholic acid (UDCA) treatment (20 mg/kg/day). Five short bowel patients (age: 53.4 ± 19.2 years) who had normal liver function and lipid plasmatic profiles received 1920 ± 300 ml of PN for 151 ± 74 days (mean PN energy intake was 27.0 ± 6.0 kcal/kg body weight, composed with 3.87 ± 1.38 g/kg of carbohydrate, 0.72 ± 0.25 g/kg of fat and 1.10 ± 0.23 g/kg of amino acids). Plasma metabolites, liver enzymes, 7-α-OH-cholesterol and steatosis levels were also evaluated before and after treatment. Student's t-tests were performed, and the results were expressed in means (±SD). RESULTS: After treatment, decreases in the absolute values of cholesterol synthesis (0.31 ± 0.12 mmol L-1 to 0.24 ± 0.11 mmol L-1; p < 0.05), FSR of cholesterol (31.6 ± 4.7% to 26.4 ± 4.7%; p = 0.06) and FSR of triglycerides (12.8 ± 5.8% to 9.2 ± 5.5%; p < 0.01) were observed. Cholesterol and alanine aminotransferase concentrations also decreased (ALT) (p < 0.05). The absolute values of triglyceride synthesis and triglyceride concentrations remained unchanged. CONCLUSIONS: In SBS patients, UDCA decreases the hepatic synthesis of triglycerides and cholesterol. These results suggest that UDCA could prevent the onset of the IFALD.

Hyperphagia in short bowel patients: Fat-free mass is a strong predictor.

OBJECTIVES: Some patients with short bowel syndrome (SBS) develop hyperphagic behavior. Such an increase in food intake stimulates intestinal adaptation and limits dependence on parenteral nutrition (PN). The aim of this study was to determine the factors modulating food consumption in patients with SBS. METHODS: The associations between oral energy intake (OEI) and anthropometric, metabolic, nutritional, and intestinal absorption-related characteristics were determined in a monocentric cohort of patients with SBS on PN with a stable nutritional status. Body composition was assessed by dual x-ray absorptiometry. Data were retrospectively collected from clinical records. RESULTS: After screening, 38 adult patients with a SBS on PN were included in this study. OEI ranged from 577 to 4054kcal/d. OEI correlated positively with weight, fat-free mass, handgrip strength, and resting energy expenditure (REE) and negatively with free triiodothyronine and C-reactive protein using Spearman correlation. Fat-free mass and thyroid-stimulating hormone remained positively correlated with OEI independently of all other parameters in a multilinear regression model. CONCLUSIONS: Fat-free mass is a strong predictor of OEI in patients with SBS on PN and without debilitating gastrointestinal symptoms. Increasing fat-free mass could be a way to stimulate OEI in these patients. Further studies are needed to assess this assumption.

Fluoride exposure and bone status in patients with chronic intestinal failure who are receiving home parenteral nutrition.

BACKGROUND AND OBJECTIVE: Metabolic bone disease is frequent in chronic intestinal failure. Because fluoride has a major effect on bones, the status of both fluoride and bone was studied in long-term home parenteral nutrition (HPN) patients. DESIGN: We studied 31 adults aged (x +/- SD) 56.3 +/- 15.1 y, mainly patients with short-bowel syndrome, who had been receiving HPN for >1 y. Bone mineral density (BMD) was measured by absorptiometry, and serum fluoride was measured by using a fluoride-sensitive electrode. All patients ate and drank ad libitum. HPN (3.4 +/- 1.2 times/wk) complemented oral nutrition. Potential explicative factors were estimated by using a linear regression model (mixed-effects model). RESULTS: Of 120 fluoride dosages (2-6/patient), 102 were above the upper normal limit (1.58 micromol/L) at the laboratory. Mean (+/- SD) daily fluoride supply was 8.03 +/- 7.71 mg (US adequate intake: 3.1 mg/d for women and 3.8 for men; tolerable upper normal limit: 10 mg/d); intravenous fluoride varied from 0.06 to 1.45 mg, and oral fluoride varied from 0.09 to 27.8 mg. Serum fluoride concentrations were correlated with creatinine clearance and fluoride supply. BMD was significantly lower in the femoral neck than in the spinal area. After adjustment for sex and the duration of HPN, only the effect of serum fluoride on spinal BMD was significant. Two patients had symptoms of fluorosis, eg, calcaneum fissures, interosseous calcifications, or femoral neck osteoporosis. CONCLUSIONS: In chronic intestinal failure, high intakes of fluoride are frequent because of the beverages ingested to compensate for stool losses. Hyperfluoremia has an effect on bone metabolism and may increase skeletal fragility. The consumption of fluoride-rich beverages for extended periods is therefore not advisable.

Chronic dehydration may impair renal function in patients with chronic intestinal failure on long-term parenteral nutrition.

BACKGROUND & AIMS: Renal impairment is a documented complication in long-term parenteral nutrition (LTPN) patients. However, the aetiologies have remained elusive. The aim of this study was to evaluate the impact of parenteral nutrition, digestive status, and hydration level on renal function in LTPN patients. METHODS: In a prospective study of 40 LTPN patients, renal function and hydration level were assessed by measurement of inulin and creatinine clearances, plasma creatinine, urea, aldosterone and renin and urinary sodium/potassium ratio. Patients were assigned to one of two groups according to their inulin clearance (normal = Group 1, 20% decrease or more = Group 2). RESULTS: Of the patients, 52.5% (21/40) had a decrease in glomerular filtration rate (-38 +/- 15%), with age taken into consideration. Patient characteristics, parenteral nutrition composition or duration and intestinal status were not different between the two groups. Urologic or nephrologic diseases were more frequent in Group 2 patients. Moreover, in Group 2 patients, a urinary sodium/potassium excretion ratio of less than 1 in 8/21 patients and plasma renin (316 +/- 298 vs. 86 +/- 53% of normal value) and aldosterone (291 +/- 464 vs. 58 +/- 36 pmol/l) that were significantly higher than in Group 1 patients suggested a hypovolemic component. CONCLUSION: Decreased renal function is frequent (52.5%) in LTPN patients. A volemic component was associated in more than 70% of them. An elevation of serum creatinine or an inversion of the urinary Na/K ratio requires an evaluation of hydration equilibration and an oral rehydration and a modification in parenteral nutrition formulation.

Replacement of long-chain triglyceride with medium-chain triglyceride/long-chain triglyceride lipid emulsion in patients receiving long-term parenteral nutrition: effects on essential fatty acid status and plasma vitamin K1 levels.

BACKGROUND: In long-term parenteral nutrition (LTPN) patients, the use of a 50:50 mixture of medium- and long-chain triglyceride emulsion (MCT/LCT) has been suggested to prevent or correct fatty liver infiltration. However, the use of MCT/LCT lipid emulsion results in a 50% reduction of essential fatty acids and vitamin K1 supply and could induce essential fatty acid and vitamin K1 deficiencies. This study evaluated the effect of a long-term infusion of MCT/LCT lipid emulsion on plasma fatty acid (FA) and vitamin K1 levels on LTPN patients. METHODS: In a prospective nonrandomized crossover study, we measured plasma phospholipid FA composition by gas chromatography and vitamin K1 levels by high-performance liquid chromatography in 11 LTPN patients before and after a 4-month replacement of the usual 20% LCT lipid emulsion (20% Lipoven; Fresenius-Kabi France, Sèvres, France) by a 20% MCT/LCT lipid emulsion (Medialipide B; Braun Medical, Boulogne, France). RESULTS: Patient received LTPN for 46 +/- 40 months; IV lipid emulsion was 827 +/- 336 mL/week. MCT/LCT lipid substitution did not change most of the essential plasma fatty acid concentrations and did not induce essential fatty acid deficiency. With both lipid emulsions, the triene/tetraene (20:3n-9/20:4n-6) ratio remained within the normal ranges. However, with MCT/LCT lipid emulsion, 22:4n-6 (LCT: 0.50 +/- 0.12; MCT/LCT: 0.63 +/- 0.11%) and 22:5n-6 (LCT: 0.32 +/- 0.11; MCT/LCT: 0.48 +/- 0.15%) increased significantly (p = .022 and 0.011, respectively). Plasma vitamin K1 levels decreased drastically with MCT/LCT lipid emulsion. CONCLUSIONS: An amount of 2.85 +/- 1.55 g x kg(-1) week(-1) of MCT/LCT lipid emulsion neither induced essential fatty acid deficiency nor improved the fatty acid disturbances usually observed in LTPN patients but did induce a drop in plasma vitamin K1 levels.

Taurolidine lock solution in the secondary prevention of central venous catheter-associated bloodstream infection in home parenteral nutrition patients.

BACKGROUND & AIMS: Central venous catheter-associated bloodstream infection (CBSI) is a serious complication in patients on home parenteral nutrition (HPN). The aim was to analyze the impact of taurolidine-citrate lock solution (TLS) on CBSI rate in HPN patients with a high risk of catheter infection. METHODS: This retrospective study compared CBSI rates 12 months before and 12 months after implementation of TLS. In the first period, only standardized strategies were used to reduce the CBSI rate. In the second period, TLS was injected into the catheter at the end of parenteral nutrition. The CBSI rate with a confident interval was calculated as Poisson event rates, and compared by testing for homogeneity of rates. RESULTS: 15 patients were included. During the 24 months, the CBSI rate was 6.58/1000 catheter-days in the first period and 1.09/1000 catheter-days in the second period (p < 0.001). In patients with TLS once a week (n = 8), the CBSI rate decreased from 4.8/1000 catheter-days to 1.37/1000 catheter-days (p = 0.02) and in patients with TLS after each TPN (n = 7), the CBSI rate decreased from 8.61/1000 catheter-days to 0.78/1000 catheter-days (p = 0.001). CONCLUSION: In HPN patients, TLS associated with standardized precautions significantly reduced the CBSI rate.