Harry M. Vars Award Candidate Abstracts

Abstract

Monday, March 4, 2024

Premier Paper Session and Vars Award Competition

Harry M. Vars Award Candidate

Jana K. Ponce, PhD, RD; Jerrod Anzalone, MS; Makayla Schissel, MPH; Kristina Bailey, MD; Harlan Sayles, MS; Megan Timmerman, MPA, RD; Mariah Jackson, MMN, RDN; Corrine Hanson, PhD, RD

University of Nebraska Medical Center, Omaha

Financial Support: The project described was supported by the National Institute of General Medical Sciences, U54GM104942 and U54GM115458. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Background: Post-COVID conditions consist of a wide range of new, returning, or ongoing health problems people can experience four or more weeks after first being infected with the virus that causes COVID-19 and may ultimately result in death. However, little is known about which individuals develop post-COVID conditions or long COVID and why. While the association between malnutrition and acute SARS-CoV-2 infection is well documented, less is known about its influence on post-acute outcomes. Therefore, we aimed to address this knowledge gap by evaluating malnutrition's impact on post-COVID-19 sequelae, including death, the development of long COVID, and SARS-CoV-2 reinfection.

Methods: Using data collected through April 2023, this retrospective cohort study leveraged the rich data infrastructure of the National COVID Cohort Collaborative (N3C), a secure enclave from more than 80 US sites contributing electronic health record (EHR) data collected during routine care on COVID-19 patients. Malnutrition, as defined by the presence of specific ICD-10-CM codes within the EHR before a diagnosis of COVID-19, served as the primary exposure of the study. Patients were separated into groups based on malnutrition status (malnutrition vs. no malnutrition). Multivariable Cox proportional hazard models were used to evaluate adjusted hazard ratios (aHRs) on the following post-acute (day 28-180) sequelae of severe acute respiratory syndrome coronavirus 2 (PASC): (a) death, (b) a diagnosis of long COVID, and (c) COVID-19 reinfection >90 days after initial infection. In a subgroup analysis limited to patients without a history of malnutrition who were hospitalized within 14 days of COVID-19 diagnosis, subjects were separated into 2 groups: (1) no malnutrition and (2) hospital-acquired (HAC) malnutrition. HAC malnutrition was defined as the addition of one of the above-mentioned diagnostic codes to a patient's medical record between days 5 and 27 of hospitalization.

Results: The final cohort included 3,817,493 individuals with COVID-19, of which 55,749 (1.5%) had a history of malnutrition (Table 1). Following adjustment for confounders, individuals with malnutrition had 2.14 times (aHR: 2.14; 95% CI: 2.02, 2.27) higher risk of death in the post-acute period than those without malnutrition (Figure 1) but had a lower risk (aHR: 0.92; 95% CI: 0.87, 0.97) to be diagnosed with long COVID in the post-acute period (Figure 1). Patients with malnutrition had a 1.60 (aHR: 1.62; 95% CI: 1.51, 1.74) higher risk of having a SARS-CoV-2 reinfection greater than 90 days after initial infection than individuals without. Of 136,648 patients in the subgroup analysis, 3153 (2.3%) were diagnosed with malnutrition between hospital days 5 and 27 (Table 2). Patients in the HAC malnutrition group had a 1.70 (aHR: 1.7; 95% CI: 1.44, 2.01) higher risk of death in the post-acute period and 1.50 (aHR: 1.5; 95% CI: 1.3, 1.73) higher risk of being diagnosed with long COVID (Figure 2). No difference in SARS-CoV-2 reinfection greater than 90 days after initial infection was observed between groups.

Conclusion: Both pre-existing and HAC malnutrition have significant associations with post-COVID-19 sequelae. Early identification and intervention of malnutrition in patients with COVID-19 may mitigate PASC.

FIGURE 2. Forest Plot of Hazard Ratios in Patients With HAC Malnutrition.

Harry M. Vars Award Candidate

Asia M. Nakakura, MS, RD, CSSD, CNSC¹; Beth A. Shields, MS, RD, LDN, CNSC²

¹Walter Reed Army Medical Center, Bethesda, MD; ²US Army Institute of Surgical Research, San Antonio, TX

Financial Support: None Reported.

Background: Two randomized control trials have evaluated the proportion of fat to carbohydrate in critically ill burn patients with more clinical benefits found in the higher carbohydrate (60%-65% of total kcals), lower fat (12%-15%) treatment groups, to include faster wound healing, fewer wound infections, decreased hospital stay, and less pneumonia. The purpose of this performance improvement project was to assess if our patients who received a higher proportion (60%) of enteral carbohydrates had lower incidence of fungal infections, an increased rate of wound healing, and a decrease in mortality with no change in incidence of ischemic bowel compared to patients on higher fat, lower carbohydrate enteral feedings.

Methods: Prior to February 2022, the use of a standard, high protein enteral formula (52% carbohydrate, 23% fat, 25% protein) combined with a protein modular was our standard of practice for feeding a burn patient. In February of 2022, we implemented a higher carbohydrate feeding protocol with the addition of a carbohydrate modular to increase the proportion of carbohydrates given to 60% of the calorie goal while still meeting estimated protein needs (≥25%). Calorie needs were calculated using the Milner Equation and adjusted with serial DEXA scans, and adequacy of protein intake is monitored with the use of daily nitrogen balance studies. This PI project was approved by our Regulatory Compliance Division. Patients admitted to the burn intensive care unit from February 2022 through October 2022 with at least 20% total body surface area (TBSA) (20), who received a carbohydrate modular, who required surgery, who were between 18 and 70 years old, and who received tube feeding were included in this analysis and were matched by age (±10 years), burn size (±10% TBSA), and gender to patients admitted before the implementation of the carbohydrate modular. Patients were excluded who developed ischemic bowel prior to the initiation of tube feeding. Statistical analysis included counts, percentages, medians with interquartile ranges (IQR), the Kruskal-Wallis test, and the Fisher's Exact test, with P < 0.05 considered significant.

Results: A total of 26 patients were included for analysis in this performance improvement project: 15% were female (n = 4) with a median age of 45.5 years old (IQR: 37-55), and 33.5% TBSA burn (IQR: 23-40). Patients who received the carbohydrate modular had significantly (P = 0.03) faster wound healing rates, at 1.0%TBSA/day (IQR: 0.8-1.4), as compared to matched patients who did not, at 0.5%TBSA/day (IQR: 0-1.1). Fungal infection was present in 1 patient (8%) who received the carbohydrate modular and 2 patients (15%) who did not (P = 0.50). The prevalence of ischemic bowel was seen in 1 (8%) patient who received the carbohydrate modular as well as 1 (8%) who did not (P = 0.76). Additionally, patients who received the additional carbohydrate modular had an 8% mortality rate compared to the 38% mortality rate of patients who did not (P = 0.08).

Conclusion: This performance improvement project found that administering a higher proportion of carbohydrate with the use of a carbohydrate modular resulted in improved healing rates in critically ill burn patients with no significant difference in fungal infection or ischemic bowel rates. Mortality of 38% versus 8% did not reach statistical significance in these 26 patients. Based on the results of this performance improvement project, we intend to continue supplementation with the carbohydrate modular, as it was associated with improved wound healing in our burn patients. Prospective randomized controlled research is needed in a multicentered setting to determine the impact of carbohydrate on clinical outcomes.

Harry M. Vars Award Candidate

Osman Mohamed Elfadil, MBBS; Danelle A. Olson, RDN; Adele K. Pattinson, RDN; Raj N. Shah, MBBS; Ryan T. Hurt, MD, PhD; Manpreet S. Mundi, MD

Mayo Clinic, Rochester, MN

Financial Support: Grant from Nestlé.

Background: Peptide-based formulas (PBFs) are commonly used for enteral nutrition (EN) therapy, especially pragmatically for EN-intolerant patients. Various PBFs are available in the market with data supporting their efficacy and safety. However, there is a paucity of data regarding biomolecular changes with EN in general and particularly with PBFs. In this study, we present changes in inflammatory markers, fatty acid profile, and metabolomics with the use of fortified high-protein PBF.

Methods: A pilot single-center prospective cohort study to evaluate feeding tolerance and biochemical changes with a fish oil fortified 100% whey high protein peptide-based formula (PBF) was approved by the IRB. Voluntary participants switched from the standard polymeric formula (SPF) to the study PBF for 14 days (Day 0 to Day 13), preceded by a gradual transition period of up to 3 days. We included adult patients with established enteral access who receive ≥90% of their nutrition needs enterally, had no active colitis, and were not undergoing treatment for cancer. In addition to completing a formula consumption and tolerance diary daily, optional biochemical and metabolomics testing was performed in those who opted in and provided blood samples at enrollment (baseline) and at the end of the study (Day 13). In this report, we present the cohort of patients who completed lab tests, including comprehensive fatty acid profile, proteomics, and lipidomics.

Results: Twenty-five participants completed this study (mean age 60.3 ± 16.3 years; 72% female). Of these, 18 completed baseline and end-of-study blood tests for metabolomics, and 17 had blood tests for the biochemical profile. Compared to baseline, C peptide and insulin increased at the end of the study by a median of 36% and 13%, respectively, possibly reflecting an insulinotropic effect of whey protein. While remaining within the reference normal range, BUN increased by a median of 15%. Additional key blood and biochemical indices are shown in Figure 1. Omega-3 fatty acids in plasma significantly increased including a 469% increase for EPA and 143% for DHA (Table 1). While linoleic acid remained stable, arachidonic acid, mead acid, and triene:tetraene ratio decreased. Proteomics analyses show amino acids that increased by ≥ 20% or decreased by any % from selected amino acids of clinical relevance (Table 1). The largest change was noted for increases in glutamic acid, aspartic acid, and a-aminoadipic acid and decreases in arginine and cystine. A significant increase in metabolites of arginine, such as ornithine, was observed, indicating that the negative change in arginine plasma levels may be associated with utilization by cells such as the enterocytes. In relation to lipidomics, several lipid ions showed significant change with exposure to the study formula (adjusted P value ≤ 0.05) (Table 2). The upregulation of phosphatidylinositols (PI 18:0_22:6) observed is of special interest as PI is a neurotransmitter with an important role in cognition and memory as well as lipid metabolism in the liver. Similar benefits for phosphatidylcholines (PC) are known. Moreover, PC also has a protective property for the gut wall from ulcerative colitis. The clinical implications of the upregulation of lysophosphatidylcholine remain controversial.

FIGURE 1. Change in Hemogram and Metabolic Panels. n = 17.

Abbreviations: IQR, interquartile range; PBF+AF, peptide-based diet; SPF, standard polymeric formula.

*Reference ranges: https://www.mayocliniclabs.com/test-catalog/overview/82042#Clinical-and-interpretive

^#Reference ranges: https://www.mayocliniclabs.com/test-catalog/overview/9265#Clinical-and-interpretive

Abbreviations: LPC, lysophosphatidylcholine; LPI, lysophosphatidylinositol; PC, phosphatidylcholine; PI, phosphatidylinositol; TG, triglyceride.

Harry M. Vars Award Candidate

Jiwei Wang; Jing Du; Ming Xie

Department of General Surgery, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China

Financial Support: This work was supported by the National Natural Science Foundation of China (81969105).

Background: Parenteral nutrition (PN) is a life-saving therapy in patients with gastrointestinal dysfunction. Enterogenous infection caused by PN-related intestinal barrier injury is one of the serious complications of PN, which limits its clinical application. Previous studies have shown that the gut microbiota dysbiosis triggers intestinal barrier damage during PN, but the specific molecular mechanisms of the intermediate process still remain unclear. Short-chain fatty acids (SCFAs), one of the metabolites of gut microbiota, can regulate intestinal barrier function through a series of receptors and signaling pathways, including the regulation of autophagy. However, the changes in gut microbiota metabolites and intestinal autophagy levels during parenteral nutrition are still unknown. Here, we investigated the changes of gut microbiota, luminal SCFAs and intestinal autophagy in a PN mouse model. Furthermore, the mechanism of specific fatty acids regulating autophagy were examined.

Methods: Eight-week-old male SPF mice (n = 20) were surgically implanted with rubber catheters in the right jugular vein, and then were randomly divided into EN group (received a standard laboratory diet and infused intravenously with 0.9% saline) and PN group (received continuous infusion of isocaloric and isonitrogenous PN solution). After 7 days. Mice were anesthetized and sacrificed. Small intestinal samples and luminal contents were collected. Changes in gut microbiota were examined by 16 s sequencing. Targeted metabolomic interrogation was used to identify changes in intestinal SCFAs. In a separate experiment, Caco-2 cells were treated with intestinal solution from EN and PN mouse model, specific fatty acid selected from the previous experiment (PN + SCFAs), autophagy agonists (PN + Rapamycin) and inhibitors (PN + 3-MA) respectively.

Results: Compared with the EN group, the abundance of Proteobacteria in the PN group increased, while the abundance of Bacteroides bacteria was significantly decreased, which was closely related to the production of SCFAs (Figure 1A-C). Propyl acetate was the only fatty acid with significant differences between the two groups and showed a significant decrease in the PN group (Figure 1D). Compared with the EN group, mice in the PN condition showed increased edema of the intestinal mucosa, enlarged crypt spaces, loose intestinal villi, and disrupted epithelial cell arrangement (Figure 1E). There was no significant difference in bacterial translocation in the intestine (Figure 1F). The levels of IL-6 and TNF-α in the intestinal tissue of the PN group were significantly higher than those of the EN group (Figure 1G-H). Protein levels of ZO-1, Claudin-1, occludin, MUC2, lysozyme, and α-defensin 5 of the PN group were significantly reduced compared to those of the EN group (Figure 2A-B). Moreover, the phosphorylation level of AMPK and LC3II/I ratio in the intestinal tissue of the PN group were significantly increased, while the phosphorylation level of mTOR was significantly reduced (Figure 2C). The mRNA levels of ATG3 and ATG7 in the PN group were significantly higher than those in the EN group (Figure 2D). In Caco-2 cells, propyl acetate promotes cell proliferation in a dose and time-dependent manner (Figure 3A-B). Compared to the cells treated with PN solution alone, Claudin-1 and occludin increased (Figure 3C-D), while IL-6 and TNF-α decreased in the cells treated with PN solution plus propyl acetate (Figure 3E-F). The addition of propyl acetate inhibited AMPK/mTOR pathway and alleviated the excessive autophagy caused by PN solution in Caco-2 cells (Figure 4).

FIGURE 4. Emicroscope scanning and autophagy levels in Caco-2 cells treated with propyl acetate and intestinal solution. (A) Microstructure of Caco-2 cells and autophagosome (white arrows). (B-C) Western blot of AMPK, mTOR, and LC3. (D) Relative mRNA expression of atg3 and atg7 in Caco-2 cells (*P < 0.05 compared with the cells treated with intestinal solution from EN mice, ∆ P < 0.05 compared with the cells treated with intestinal solution from PN mice).

Harry M. Vars Award Candidate

Megan Follett, MS, RD¹; Alexis Biasotti¹; Sara Schumacher, BA¹; Laurel Nunez, MS²; Bethaney Fehrenkamp, MD, PhD²; Yimin Chen, PhD, RDN¹

¹University of Idaho, Moscow, ID; ²Idaho WWAMI Medical Education, University of Idaho, Moscow, ID

Financial Support: ASPEN Rhoads Research Foundation.

Background: Human milk (HM) is associated with positive outcomes in infants compared to bovine-derived infant formula (IF). Specifically, infants primarily fed HM are associated with lower incidences of ear infection, asthma, and necrotizing enterocolitis. Various HM components have been shown to improve intestinal tight barrier function in both animal and human models. In a study of preterm infants, intestinal barrier function was better in those fed a diet of majority (75% intake) HM compared to majority IF. The association of HM with positive health outcomes may be due to an improvement in intestinal barrier function, thus reducing pathogenic bacterial translocation inducing systemic immune responses. While there is scarce evidence that higher HM intake increases barrier function compared with IF in infants, the piglet model allows direct intestinal barrier function measures in response to exclusive feedings without confounding variables with human infants. Hypothesis: Exclusive HM-feeding will result in better intestinal barrier function and more gap junction proteins compared to exclusive IF in piglets.

Methods: Ten 2-day-old piglets were exclusively fed unpasteurized HM or IF for 28 days. Daily feeding volumes were calculated using morning weights to meet estimated needs of a growing piglet. The feedings were isocaloric and isonitrogenous. At necropsy, intestinal samples were harvested and tested in Ussing Chambers (measure intestinal barrier function through measurements of resistance; uA*min). Each intestinal section (duodenum, jejunum, ileum, colon) was measured in duplicates. Tissues were treated with five pharmacological agents as stimulants. Increased intestinal resistance indicated better intestinal barrier function. Results of nine piglet samples (5 HM vs 4 IF) were viable for data analyses. Tissue response values were calculated using Area Under the Curve. Total responses for each tissue and sample were combined to give an overall response and averaged out to each tissue type. E-cadherin (plays a key role in intestinal development and barrier function) was measured using ELISA on the first three pairs of piglets. Data were assessed for normality; nonparametric and Mann-Whitney U tests were performed to compare groups (HM vs IF) for each intestinal section.

Results: There were no statistical differences in intestinal resistance between duodenal, jejunal, and ileal tissues between HM- vs. IF-fed piglets. There was a trend towards higher intestinal resistance in HM-fed colon (8.86 uA*min, IQR 3.02, 26.61) compared with IF (0.95 uA*min, IQR –6.68, 8.42; P = 0.2). E-cadherin protein in the jejunum was significantly higher in HM-fed versus IF-fed piglets (P = 0.0217) and approaching significance in the ileum (P = 0.1323) of the HM group compared with IF.

Conclusion: In this study, we observed a trend in better barrier function in HM-fed colon compared with IF; yet, when E-cadherin was quantified, significance and trend were observed in jejunum and ileum, respectively, not colon. Further research is needed with increased sample size to analyze barrier function and gap junction proteins between feeding types. Using techniques differentiating between intracellular vs. paracellular barrier would be useful, coupled with quantification of additional tight and gap junction proteins on the full set of piglets to strengthen and differentiate the functional vs. protein quantification data.