Liver steatosis in adult patients on home parenteral nutrition

Investigation of parenteral nutrition-induced hepatotoxicity using human liver spheroid co-cultures

Parenteral nutrition (PN) is typically administered to individuals with gastrointestinal dysfunction, a contraindication for enteral feeding, and a need for nutritional therapy. When PN is the only energy source in patients, it is defined as total parenteral nutrition (TPN). TPN is a life-saving approach for different patient populations, both in infants and adults. However, despite numerous benefits, TPN can cause adverse effects, including metabolic disorders and liver injury. TPN-associated liver injury, known as intestinal failure-associated liver disease (IFALD), represents a significant problem affecting up to 90% of individuals receiving TPN. IFALD pathogenesis is complex, depending on the TPN components as well as on the patient's medical conditions. Despite numerous animal studies and clinical observations, the molecular mechanisms driving IFALD remain largely unknown. The present study was set up to elucidate the mechanisms underlying IFALD. For this purpose, human liver spheroid co-cultures were treated with a TPN mixture, followed by RNA sequencing analysis. Subsequently, following exposure to TPN and its single nutritional components, several key events of liver injury, including mitochondrial dysfunction, endoplasmic reticulum stress, oxidative stress, apoptosis, and lipid accumulation (steatosis), were studied using various techniques. It was found that prolonged exposure to TPN substantially changes the transcriptome profile of liver spheroids and affects multiple metabolic and signaling pathways contributing to liver injury. Moreover, TPN and its main components, especially lipid emulsion, induce changes in all key events measured and trigger steatosis.

NAFLD, MAFLD, and beyond: one or several acronyms for better comprehension and patient care

The term non-alcoholic fatty liver disease (NAFLD) has rapidly become the most common type of chronic liver disease. NAFLD points to excessive hepatic fat storage and no evidence of secondary hepatic fat accumulation in patients with "no or little alcohol consumption". Both the etiology and pathogenesis of NAFLD are largely unknown, and a definitive therapy is lacking. Since NAFLD is very often and closely associated with metabolic dysfunctions, a consensus process is ongoing to shift the acronym NAFLD to MAFLD, i.e., metabolic-associated fatty liver disease. The change in terminology is likely to improve the classification of affected individuals, the disease awareness, the comprehension of the terminology and pathophysiological aspects involved, and the choice of more personalized therapeutic approaches while avoiding the intrinsic stigmatization due to the term "non-alcoholic". Even more recently, other sub-classifications have been proposed to concentrate the heterogeneous causes of fatty liver disease under one umbrella. While awaiting additional validation studies in this field, we discuss the main reasons underlying this important shift of paradigm.

Long-term home parenteral nutrition and profile of amino acids in serum and their loss in urine

Amino acids are an essential part of parenteral nutrition. This study aimed to determine the serum profile of amino acids and their loss in urine in patients with long-term home parenteral nutrition (HPN) during 12 h of infusion in comparison with similar parameters in the remaining 12 h as well as in healthy participants. We enrolled forty-five patients with long-term HPN for 6-75 (median, 33) months. The indication for HPN was short bowel syndrome secondary to radical resection of the small intestine following complications of Crohn's disease. HPN was administered via two-chamber all-in-one bags prepared in a hospital pharmacy overnight for 12 h each day. The average dose of amino acids, carbohydrates and fats administered was 1·5, 3·4 and 0·68 g/kg per d, respectively, at an infusion rate of 0·11, 0·28 and 0·06 g/kg per h, respectively. The levels of essential amino acids in the serum of the patients were not significantly different from those in healthy individuals; however, of the non-essential amino acids, cystine and glutamine levels were lower and glycine and ornithine levels were higher in the patients (P < 0·05). Excretion of amino acids in the urine during 12 h of infusion at an infusion rate of 0·11 g/kg per h was 301 mg, while it was 104 mg during the remaining 12 h (P < 0·0001). Our patients on long-term HPN had a normal serum profile of essential amino acids. The total urinary excretion of amino acids during 12 h of infusion accounted for only 0·34 % (0·23-0·46) of the administered dose.

Hepatic dysfunction in patients receiving intravenous lipid emulsions

PURPOSE

Until recently, intravenous lipid emulsions (ILEs) have consisted of soybean oil (SO) only. This review addresses recent developments in the field, including the problem of intestinal failure associated liver disease (IFALD) that can occur with the use of ILEs in children and adults, and newer ILEs that may minimize and reverse IFALD.

RECENT FINDINGS

Cholestasis is the primary manifestation of IFALD in premature infants receiving ILEs, whereas in older children and adults, steatosis is predominant. Two alternative ILEs have been extensively investigated for both safety and efficacy. SMOF, an ILE containing medium chain triglyceride, soybean oil, olive oil and fish oil (FO), is now widely used in both children and adults. A newer FO ILE is approved for use in children only. However, in case reports FO ILE has been shown to improve IFALD in adults. A number of new studies suggest that cholestasis from ILEs is dose-related. IFALD does not improve in many patients after transition from SO to SMOF, but partial or complete replacement with FO can halt and reverse IFALD.

SUMMARY

Adverse hepatic effects from ILEs are to some extent dose-related. Overfeeding with fat or with carbohydrate, or simply providing excessive calories in general, may be responsible. More research is needed investigating dose-related effects of macronutrients on liver injury.

Synergistic and Detrimental Effects of Alcohol Intake on Progression of Liver Steatosis

Nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) are the most common liver disorders worldwide and the major causes of non-viral liver cirrhosis in the general population. In NAFLD, metabolic abnormalities, obesity, and metabolic syndrome are the driving factors for liver damage with no or minimal alcohol consumption. ALD refers to liver damage caused by excess alcohol intake in individuals drinking more than 5 to 10 daily units for years. Although NAFLD and ALD are nosologically considered two distinct entities, they show a continuum and exert synergistic effects on the progression toward liver cirrhosis. The current view is that low alcohol use might also increase the risk of advanced clinical liver disease in NAFLD, whereas metabolic factors increase the risk of cirrhosis among alcohol risk drinkers. Therefore, special interest is now addressed to individuals with metabolic abnormalities who consume small amounts of alcohol or who binge drink, for the role of light-to-moderate alcohol use in fibrosis progression and clinical severity of the liver disease. Evidence shows that in the presence of NAFLD, there is no liver-safe limit of alcohol intake. We discuss the epidemiological and clinical features of NAFLD/ALD, aspects of alcohol metabolism, and mechanisms of damage concerning steatosis, fibrosis, cumulative effects, and deleterious consequences which include hepatocellular carcinoma.

Nutrition Management Through Nitrogen Balance Analysis in Patient With Short Bowel Syndrome

Patients with short bowel syndrome (SBS) have a high risk of developing parenteral nutrition (PN)-associated complications. Therefore, diet or enteral nutrition and PN should be modified to limit such complications. N balance analysis is a method of calculating the amount of protein required to achieve N equilibrium in the body based on intake and excretion. It is important to reduce dependence on PN and achieve the recommended range of N balance 2–4 g with an appropriate diet. We report a recent experience with nutrition modification using N balance analysis and suggest it as a useful method to reduce dependence on PN in nutrition management of SBS patients and in continuing active intestinal rehabilitation.

Intestinal Barrier and Permeability in Health, Obesity and NAFLD

The largest surface of the human body exposed to the external environment is the gut. At this level, the intestinal barrier includes luminal microbes, the mucin layer, gastrointestinal motility and secretion, enterocytes, immune cells, gut vascular barrier, and liver barrier. A healthy intestinal barrier is characterized by the selective permeability of nutrients, metabolites, water, and bacterial products, and processes are governed by cellular, neural, immune, and hormonal factors. Disrupted gut permeability (leaky gut syndrome) can represent a predisposing or aggravating condition in obesity and the metabolically associated liver steatosis (nonalcoholic fatty liver disease, NAFLD). In what follows, we describe the morphological-functional features of the intestinal barrier, the role of major modifiers of the intestinal barrier, and discuss the recent evidence pointing to the key role of intestinal permeability in obesity/NAFLD.

Serum Scoring and Quantitative Magnetic Resonance Imaging in Intestinal Failure-Associated Liver Disease: A Feasibility Study

(1) Background: Intestinal failure-associated liver disease (IFALD) in adults is characterized by steatosis with variable progression to fibrosis/cirrhosis. Reference standard liver biopsy is not feasible for all patients, but non-invasive serological and quantitative MRI markers for diagnosis/monitoring have not been previously validated. Here, we examine the potential of serum scores and feasibility of quantitative MRI used in non-IFALD liver diseases for the diagnosis of IFALD steatosis; (2) Methods: Clinical and biochemical parameters were used to calculate serum scores in patients on home parenteral nutrition (HPN) with/without IFALD steatosis. A sub-group underwent multiparameter quantitative MRI measurements of liver fat fraction, iron content, tissue T1, liver blood flow and small bowel motility; (3) Results: Compared to non-IFALD (n = 12), patients with IFALD steatosis (n = 8) demonstrated serum score elevations in Enhanced Liver Fibrosis (p = 0.032), Aspartate transaminase-to-Platelet Ratio Index (p < 0.001), Fibrosis-4 Index (p = 0.010), Forns Index (p = 0.001), Gamma-glutamyl transferase-to-Platelet Ratio Index (p = 0.002) and Fibrosis Index (p = 0.001). Quantitative MRI scanning was feasible in all 10 sub-group patients. Median liver fat fraction was higher in IFALD steatosis patients (10.9% vs 2.1%, p = 0.032); other parameter differences were non-significant; (4) Conclusion: Serum scores used for non-IFALD liver diseases may be useful in IFALD steatosis. Multiparameter MRI is feasible in patients on HPN.