Nutrition in acute pancreatitis

Plasma Exosomes Aggravate Acute Pancreatitis by Promoting M1 Polarization of Adipose Tissue Macrophages in Obesity-Related Severe Acute Pancreatitis

BACKGROUND AND AIMS

Obesity may be a risk factor for severe acute pancreatitis (SAP). However, its precise mechanism is not yet fully understood.

METHODS

We fed rats with a standard laboratory diet (SLD) and a high-fat diet (HFD). SAP model rats were established by retrograde injection of sodium taurocholate. Serum non-esterified fatty acids (NEFAs), lipase (LPS), and myeloperoxidase (MPO) were measured, as were adipose IL-1, IL-6, IL-10, and TNF-α levels. HE staining was performed to determine the severity of pancreatitis. Serum exosomes were extracted from rats with obesity-related SAP, verified by transmission electron microscopy (TEM) and western blot analysis, and co-cultured with THP-1 cells. Flow cytometry was used to analyze the M1 and M2 phenotypes of macrophages in adipose tissues and THP-1 cells. Q-PCR was used to analyze the levels of IL-1, IL-6, IL-10, and TNF-α in each group of cells.

RESULTS

The body weight and serum NEFA concentrations of rats in the HFD group were significantly higher than those in the SLD group. Adipose tissue macrophages in the HFD group exhibited a higher percentage of the M1 type than those in the SLD group. The severity of pancreatitis were significantly increased in the HFD + SAP group. Pro-inflammatory macrophages and cytokines were significantly higher in the HFD + SAP group and THP-1 cells co-cultured with serum exosomes extracted from rats with obesity-related SAP.

CONCLUSIONS

Obesity might worsen the severity of pancreatitis by amplifying the immune response and activating M1 polarization in adipose tissue macrophages via serum exosomes in rats of obesity-related SAP. In our study, we isolated exosomes from the serum of mice with obesity-related SAP. After inducing THP-1 cells to become M0-typed macrophages, we co-cultured the cells with exosomes and observed that exosomes from obesity-related SAP increased the proportion of M1-typed macrophages and promoted the release of pro-inflammatory factors such as IL-1, IL-6, and TNF. Therefore, obesity might worsen the severity of pancreatitis by amplifying the immune response and activating M1 polarization in adipose tissue macrophages via serum exosomes in rats of obesity-related SAP.

Nutrition in Acute Pancreatitis: From the Old Paradigm to the New Evidence

The nutritional management of acute pancreatitis (AP) patients has widely changed over time. The "pancreatic rest" was the cornerstone of the old paradigm, and nutritional support was not even included in AP management. Traditional management of AP was based on intestinal rest, with or without complete parenteral feeding. Recently, evidence-based data underlined the superiority of early oral or enteral feeding with significantly decreased multiple-organ failure, systemic infections, surgery need, and mortality rate. Despite the current recommendations, experts still debate the best route for enteral nutritional support and the best enteral formula. The aim of this work is to collect and analyze evidence over the nutritional aspects of AP management to investigate its impact. Moreover, the role of immunonutrition and probiotics in modulating inflammatory response and gut dysbiosis during AP was extensively studied. However, we have no significant data for their use in clinical practice. This is the first work to move beyond the mere opposition between the old and the new paradigm, including an analysis of several topics still under debate in order to provide a comprehensive overview of nutritional management of AP.

Parenteral Nutrition Overview

Parenteral nutrition (PN) is a life-saving intervention for patients where oral or enteral nutrition (EN) cannot be achieved or is not acceptable. The essential components of PN are carbohydrates, lipids, amino acids, vitamins, trace elements, electrolytes and water. PN should be provided via a central line because of its hypertonicity. However, peripheral PN (with lower nutrient content and larger volume) can be administered via an appropriate non-central line. There are alternatives for the compounding process also, including hospital pharmacy compounded bags and commercial multichamber bags. PN is a costly therapy and has been associated with complications. Metabolic complications related to macro and micronutrient disturbances, such as hyperglycemia, hypertriglyceridemia, and electrolyte imbalance, may occur at any time during PN therapy, as well as infectious complications, mostly related to venous access. Long-term complications, such as hepatobiliary and bone disease are associated with longer PN therapy and home-PN. To prevent and mitigate potential complications, the optimal monitoring and early management of imbalances is required. PN should be prescribed for malnourished patients or high-risk patients with malnutrition where the feasibility of full EN is in question. Several factors should be considered when providing PN, including timing of initiation, clinical status, and risk of complications.

Nutrition in acute pancreatitis: when, what and how

PURPOSE OF REVIEW

This review intends to discuss recently available evidence in three topics related to nutrition in patients with acute pancreatitis, namely timing of refeeding, type of nutritional therapy and its route of administration.

RECENT FINDINGS

Recent lines of research confirm that early oral feeding leads to shorter length of stay, fewer complications and lower costs in patients with acute pancreatitis. Moreover, early (<48 h) enteral nutrition led to decreased hospital mortality in patients with mild and severe acute pancreatitis; thus, in case of intolerance to oral feeding or severe disease, nutritional therapy should be offered within 24-72 h. Furthermore, enteral nutrition should be preferred against parenteral nutrition, as it is related to shorter length of stay and less complications, while initial data bring to light the potential role of the soluble dietary fibre polydextrose as an agent that could lead to faster achievement of energy goal with concomitant lower rates of feeding intolerance. Finally, enteral nutrition can be administered through gastric or jejunal feeding, depending on digestive tolerance, whereas latest data also address the safety of percutaneous gastrostomy with a jejunal extension for enteral nutrition administration. However, more data about its real benefit are warranted.

SUMMARY

Accumulating evidence confirms the importance of early oral refeeding or early administration of enteral nutrition as vital parts of the armamentarium for the management of patients with acute pancreatitis.

Effects of immediate or early oral feeding on acute pancreatitis: A systematic review and meta-analysis

BACKGROUND

The timing of oral refeeding can affect length of stay (LOS) and recovery of acute pancreatitis (AP). However, the optimal timing for oral refeeding is still controversial for AP. This meta-analysis investigated the effects of immediate or early versus delayed oral feeding on mild and moderate AP, regardless of improvement in clinical signs or laboratory indicators.

METHODS

This systematic review and meta-analysis of randomized controlled trials (RCTs) based on data from Embase, Cochrane Library, PubMed, Web of science, and CBM before August 2021. Two researchers independently used Stata16 to extract and analyse study data. Random effect model was performed for meta-analysis to calculate the risk ratio (RR) and standardized mean difference (SMD).

RESULTS

8 RCTs were selected, including 748 patients with mild to moderate AP. Patients in IOR (Immediate or early Oral Refeeding) group had less costs [SMD -0.83, 95%CI (-1.17, -0.5), P < 0.001] and shorter LOS [SMD -1.01, 95%CI (-1.17, -0.85), P < 0.001] than the DOR (Delayed Oral Refeeding) group patients. However, there was no difference in mortality [RR 0.54, 95%CI (0.11, 2.62), P = 0.44], pain relapse rate [RR 0.58, 95%CI (0.25, 1.35), P = 0.27], feeding intolerance rate [RR 0.61, 95%CI (0.28, 1.3), P = 0.2], AP progression rate [RR 0.21, 95%CI (0.04, 1.07), P = 0.06] and overall complications rate [RR 0.41, 95%CI (0.17, 1.01), P = 0.05] between the IOR and DOR groups.

CONCLUSIONS

Limited data suggest that IOR could reduce LOS and costs without increasing adverse events in mild to moderate AP.