C. Pazzeschi

Renal function in patients on long-term home parenteral nutrition and in intestinal transplant recipients

OBJECTIVE A decrease of renal function was described in patients on long-term home parenteral nutrition (HPN) for benign intestinal failure. The risk for chronic renal failure (CRF) due to frequent episodes of dehydration despite optimal HPN, is an indication for intestinal transplantation (ITx). ITx is the solid organ transplant at highest risk for developing CRF. The aim of this study was to compare the prevalence and the probability of CRF occurring in adults on HPN and after ITx. METHODS A cross-sectional and retrospective follow-up study was carried out in 2011. Renal function was evaluated at cross-sectional and at time of starting HPN or ITx, by serum creatinine concentration (mg/dL) and estimated glomerular filtration rate (eGFR), according to the Modification of Diet in Renal Disease equation (mL·min·1.73 m2). CRF was defined as eGFR <60. Duration of follow up was from time of starting treatment to time of cross-sectional. RESULTS We enrolled 33 patients on HPN and 22 who had undergone ITx. The frequency of CRF was 6% in the HPN group and 9% in the ITx group (P = 0.67) at start of treatment, and 21% and 54%, respectively (P = 0.01) at the time of the cross-sectional evaluation. During the follow-up, the annual decline of eGFR was 2.8% and 14.5%, respectively (P = 0.02). The 5-y probability of maintaining an eGFR ≥60 was 84% in the HPN group and 44% in the ITx group (P < 0.001). CONCLUSIONS The decrease of renal function and the risk for developing CRF are greater after ITx than during HPN. The risk for CRF on HPN, as a criterion for ITx, should be revised.

Functional lipidomics in patients on home parenteral nutrition: Effect of lipid emulsions

AIM To investigate the fatty acid-based functional lipidomics of patients on long-term home parenteral nutrition receiving different intravenous lipid emulsions. METHODS A cross-sectional comparative study was carried out on 3 groups of adults on home parenteral nutrition (HPN), receiving an HPN admixture containing an olive-soybean oil-based intravenous lipid emulsion (IVLE) (OO-IVLE; n = 15), a soybean- medium-chain triacylglycerol-olive-fish oil-based IVLE (SMOF-IVLE; n = 8) or HPN without IVLE (No-IVLE; n = 8) and 42 healthy controls (HCs). The inclusion criteria were: duration of HPN ≥ 3 mo, current HPN admixtures ≥ 2 mo and HPN infusions ≥ 2/wk. Blood samples were drawn 4-6 h after the discontinuation of the overnight HPN infusion. The functional lipidomics panel included: the red blood cell (RBC) fatty acid (FA) profile, molecular biomarkers [membrane fluidity: saturated/monounsaturated FA ratio = saturated fatty acid (SFA)/monounsaturated fatty acid (MUFA) index; inflammatory risk: n-6/n-3 polyunsaturated fatty acid (PUFA) ratio = n-6/n-3 index; cardiovascular risk: sum of n-3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) = n-3 index; free radical stress: sum of FA trans isomers = %trans index] and FA pathway enzyme activity estimate (delta-9-desaturase = D9D; delta-6-desaturase = D6D; delta-5-desaturase = D5D; elongase = ELO). Statistics were carried out using nonparametric tests. The amount of each FA was calculated as a percentage of the total FA content (relative%). RESULTS In the OO-IVLE group, the percentage of oleic acid in the RBCs was positively correlated with the weekly load of OO-IVLE (r = 0.540, P = 0.043). In the SMOF-IVLE cohort, the RBC membrane EPA and DHA were positively correlated with the daily amount of SMOF-IVLE (r = 0.751, P = 0.044) and the number of HPN infusions per week (r = 0.753; P = 0.046), respectively. The SMOF-IVLE group showed the highest EPA and DHA and the lowest arachidonic acid percentages (P < 0.001). The RBC membrane linoleic acid content was lower, and oleic and vaccenic acids were higher in all the HPN groups in comparison to the HCs. Vaccenic acid was positively correlated with the weekly HPN load of glucose in both the OO-IVLE (r = 0.716; P = 0.007) and the SMOF-IVLE (r = 0.732; P = 0.053) groups. The estimated activity of D9D was higher in all the HPN groups than in the HCs (P < 0.001). The estimated activity of D5D was lower in the SMOF-IVLE group than in the HCs (P = 0.013). The SFA/MUFA ratio was lower in all the HPN groups than in the HCs (P < 0.001). The n-6/n-3 index was lower and the n-3 index was higher in the SMOF-IVLE group in comparison to the HCs and to the other HPN groups (P < 0.001). The %trans index did not differ among the four groups. CONCLUSION The FA profile of IVLEs significantly influenced the cell membrane functional lipidomics. The amount of glucose in the HPN may play a relevant role, mediated by the insulin regulation of the FA pathway enzyme activities.

SUN-PP038: Lipidomics Profile of Red Blood Cell Membrane in Patients on Long-Term Home Parenteral Nutrition: Effect of Two Different Lipid Emulsions

Introduction: Lipidomics considers the structural and functional roles played by lipids and their in vivo changes due to metabolic or degradation pathways, as well as their biological consequences. We investigated the effects of two different intravenous lipid emulsions (LE) on red blood cell (RBC) membrane lipidomics of patients on home parenteral nutrition (HPN) for chronic intestinal failure. Methods: A cross sectional study was carried out on two groups of patients receiving a lipid-based HPN. Inclusion criteria: age> 18 years, no active cancer, duration of HPN > 3 months, use of the current HPN admixture > 2 months, HPN infusion > 2 / week, HPN admixture with an olive-oil based LE (OOLE) or a LE containing soy, MCT, olive and fish oils (mixed-LE). Fasting blood samples were drawn in the morning, 4–6 h after discontinuation the overnight HPN infusion. The RBC membrane fatty acid profile was analyzed by gas chromatography, according to the Lipinutragen® methodology. The single fatty acid concentrations were calculated as percentage of the total fatty acid content. The following indexes were calculated: membrane fluidity index, represented by the saturated/monounsaturated fatty acids ratio (SFA/MUFA; high value=low fluidity); inflammatory risk index, given by the omega-6/omega-3 fatty acids ratio (ω-6/ω-3, high value=high risk); the free radical stress index, represented by the % of trans isomers of fatty acids (%trans, high concentration=high radical stress); the ω-3 cardiovascular risk index, given by the sum of the ω-3 EPA and DHA content (ω-3-index, high value=low risk). Statistics. Median and Mann-Whitney U test. Results: Two groups of patients were enrolled: 15 receiving the OOLE and 8 receiving the mixed-LE. The two groups did not differ for age, BMI and the characteristics of HPN, other than the type of LE. The mixed-LE group showed a higher SMA/MUFA ratio (p= 0.017), a lower ω-6/ω-3 ratio (p<0.001) and a higher ω-3 index (p<0.001). The %TFA did not differ between the two groups. Conclusions: In comparison with an OO-LE, the mixed-LE containing fish oil was associated with a lower inflammatory risk index, a lower cardiovascular risk index and a lower cell membrane fluidity. 121