Publications by authors named "Phing-How Lou"

Background: Vegaven is a novel lipid emulsion for parenteral nutrition (PN) based on 18-carbon n-3 (ω-3) fatty acids, which elicits liver protection via interleukin-10 (IL-10) in the murine model of PN.

Objectives: In a preclinical model of PN in neonatal piglets, Vegaven was tested for efficacy and safety and compared with a mixed-oil lipid emulsion containing fish oil (SMOFlipid).

Methods: Male piglets 4-5 d old were randomly allocated to isocaloric isonitrogenous PN for 14 d, which varied only by the type of lipid emulsion (Vegaven, n = 8; SMOFlipid, n = 8).

View Article and Find Full Text PDF

Background: Due to the shortage of donor organs, an increasing number of transplant organs are harvested after circulatory arrest (donation after circulatory death [DCD]). Using a translational porcine model of DCD, this study developed and evaluated a protocol based on cardioprotection by multidrug postconditioning to optimize resuscitation of DCD hearts during ex situ heart perfusion (ESHP).

Methods: Hearts of female pigs (45.

View Article and Find Full Text PDF

Background: While lipid emulsions in modern formulations for total parenteral nutrition (TPN) provide essential fatty acids and dense calories, they also promote inflammation and immunometabolic disruptions.

Objectives: We aimed to develop a novel lipid emulsion for TPN use with superior immunometabolic actions compared with available standard lipid emulsions.

Methods: A novel lipid emulsion [Vegaven (VV)] containing 30% of 18-carbon n-3 fatty acids (α-linolenic acid and stearidonic acid) was developed for TPN (VV-TPN) and compared with TPN containing soybean oil-based lipid emulsion (IL-TPN) and fish-oil-based lipid emulsion (OV-TPN).

View Article and Find Full Text PDF

Background: Lipid emulsions are a key component of total parenteral nutrition (TPN) and are administered to patients who are unable to ingest their daily required calories orally. Lipid emulsions rich with n-6 (ω-6) PUFAs are known to cause parenteral nutrition-associated liver disease and have inflammatory side effects, whereas n-3 PUFA-rich emulsions have favourable clinical outcomes.

Objectives: The present study used targeted lipid mediator analysis to investigate the metabolism of a n-3 PUFA-rich lipid emulsion and a n-6 PUFA-rich lipid emulsion in a mouse model of TPN and in primary human monocyte-derived macrophages (MDMs) and CD4+ T cells.

View Article and Find Full Text PDF

Background & Aims: Total parenteral nutrition (TPN) causes gut atrophy, dysbiosis and leakage of the gut barrier. This study aimed to characterize the gut microbiome in response to different TPNs and tested the hypothesis whether increased gut permeability in TPN would lead to changes in the circulating bacterial DNA ("blood microbiome").

Methods: Male C57BL/6J mice were randomly allocated to the following groups for seven days (1) chow-fed control (C) without jugular vein catheter (JVC, n=6) (2) chow-fed with JVC and infusion of saline (S) (n = 6) (3) Intralipid-based TPN (n-6:n-3 ratio 7:1) (IL, n = 6) (4) Omegaven-based TPN (n-6:n-3 ratio 1:8) (OV, n = 6).

View Article and Find Full Text PDF

Objectives: Lipid mediators are bioactive lipids which help regulate inflammation. We aimed to develop an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to quantify 58 pro-inflammatory and pro-resolving lipid mediators in plasma, determine preliminary reference ranges for adolescents, and investigate how total parenteral nutrition (TPN) containing omega-3 polyunsaturated fatty acid (n-3 PUFA) or n-6 PUFA based lipid emulsions influence lipid mediator concentrations in plasma.

Methods: Lipid mediators were extracted from plasma using SPE and measured using UHPLC-MS/MS.

View Article and Find Full Text PDF

Scope: The aim of this study is to test whether the choice of the lipid emulsion in total parenteral nutrition (TPN), that is, n-3 fatty acid-based Omegaven versus n-6 fatty acid-based Intralipid, determines inflammation in the liver, the incretin profile, and insulin resistance.

Methods And Results: Jugular vein catheters (JVC) are placed in C57BL/6 mice and used for TPN for 7 days. Mice are randomized into a saline group (saline infusion with oral chow), an Intralipid group (IL-TPN, no chow), an Omegaven group (OV-TPN, no chow), or a chow only group (without JVC).

View Article and Find Full Text PDF
Article Synopsis
  • Chaperones in the endoplasmic reticulum (ER) regulate calcium ion flow into mitochondria, affecting energy production in cells.
  • Calnexin, an ER lectin, boosts the activity of the calcium pump SERCA by maintaining its redox state, which helps manage calcium availability for mitochondria.
  • Without calnexin, cells adapt by relying more on glycolysis for energy and exhibit closer proximity between the ER and mitochondria, highlighting calnexin's role in balancing energy generation between oxidative phosphorylation and glycolysis.
View Article and Find Full Text PDF

Background: While Omegaven, an omega-3 (n3) fatty acid-based lipid emulsion, fosters insulin signaling in healthy hearts, it is unknown whether beneficial metabolic effects occur in insulin-resistant diabetic hearts.

Methods: Diabetic hearts from fructose-fed Sprague-Dawley rats were perfused in the working mode for 90 minutes in the presence of 11 mM glucose and 1.2 mM palmitate bound to albumin, the first 30 minutes without insulin followed by 60 minutes with insulin (50 mU/L).

View Article and Find Full Text PDF

Total parenteral nutrition (TPN) is a life-saving therapy administered to millions of patients. However, it is associated with significant adverse effects, namely liver injury, risk of infections, and metabolic derangements. In this review, the underlying causes of TPN-associated adverse effects, specifically gut atrophy, dysbiosis of the intestinal microbiome, leakage of the epithelial barrier with bacterial invasion, and inflammation are first described.

View Article and Find Full Text PDF

Background: It is currently unknown whether acute exposure to n3 fatty acid-containing fish oil-based lipid emulsion Omegaven as opposed to the n6 fatty acid-containing soybean oil-based lipid emulsion Intralipid is more favorable in terms of insulin signaling and glucose uptake in the intact beating heart.

Methods: Sprague-Dawley rat hearts were perfused in the working mode for 90 minutes in the presence of 11 mM glucose and 1.2 mM palmitate bound to albumin, the first 30 minutes without insulin followed by 60 minutes with insulin (50 mU/L).

View Article and Find Full Text PDF

Purpose: Intralipid (ILE), a clinically used lipid emulsion, reduces ischemia-reperfusion (IR) injury in healthy and infarct-remodelled rat hearts. We tested whether ILE is also cardioprotective in large porcine hearts in the context of the donation after circulatory death (DCD) model, where human hearts are procured for transplantation after cardiac arrest and thus are exposed to significant IR injury.

Methods: After induction of anesthesia, surgical preparation, termination of ventilator support, and cardiac arrest, hearts of female pigs were procured following a 15 min standoff period, with an optimized normokalemic crystalloid adenosine-lidocaine cardioplegia.

View Article and Find Full Text PDF

Background: Despite an array of cardioprotective interventions identified in preclinical models of ischemia-reperfusion (IR) injury, successful clinical translation has not been achieved. This study investigated whether drugs routinely used in clinical anesthesia influence cardioprotective effectiveness by reducing effects of reactive oxygen species (ROS), upstream triggers of cardioprotective signaling. Effects of propofol, sevoflurane, or remifentanil were compared on postischemic functional recovery induced by ROS-mediated postconditioning with Intralipid.

View Article and Find Full Text PDF

Despite the fact that skeletal muscle insulin resistance is the hallmark of type-2 diabetes mellitus (T2DM), inflexibility in substrate energy metabolism has been observed in other tissues such as liver, adipose tissue, and heart. In the heart, structural and functional changes ultimately lead to diabetic cardiomyopathy. However, little is known about the early biochemical changes that cause cardiac metabolic dysregulation and dysfunction.

View Article and Find Full Text PDF

The clinically used lipid emulsion Intralipid (ILE) reduces ischemia reperfusion injury in healthy rodent hearts. We tested whether ILE is cardioprotective in postinfarct remodeled hearts. Post-infarct remodeled and sham Sprague-Dawley rat hearts were perfused in working mode and subjected to ischemia (15 minutes) and reperfusion (30 minutes).

View Article and Find Full Text PDF
Article Synopsis
  • The movement of calcium ions (Ca(2+)) between the endoplasmic reticulum (ER) and mitochondria is crucial for maintaining cellular metabolism, especially in tumor cells where this process is often disrupted, contributing to chemotherapy resistance and tumor growth.
  • TMX1, a redox-sensitive protein located at the mitochondria-associated membrane (MAM), is linked to the regulation of this Ca(2+) flux; low levels of TMX1 result in altered calcium dynamics that favor cancer progression.
  • TMX1 functions as a tumor suppressor by enhancing mitochondrial ATP production and apoptosis, but it needs specific modifications to effectively target MAM and facilitate ER-mitochondria communication.
View Article and Find Full Text PDF

Background: The IV anesthetic, propofol, when administered as fat emulsion-based formulation (Diprivan) promotes insulin resistance, but the direct effects of propofol and its solvent, Intralipid, on cardiac insulin resistance are unknown.

Methods: Hearts of healthy and type-2 diabetic rats (generated by fructose feeding) were aerobically perfused for 60 minutes with 10 μM propofol in the formulation of Diprivan or an equivalent concentration of its solvent Intralipid (25 μM) ± insulin (100 mU•L). Glucose uptake, glycolysis, and glycogen metabolism were measured using [H]glucose.

View Article and Find Full Text PDF

Background: Insulin resistance and early type-2 diabetes are highly prevalent. However, it is unknown whether Intralipid® and sevoflurane protect the early diabetic heart against ischemia-reperfusion injury.

Methods: Early type-2 diabetic hearts from Sprague-Dawley rats fed for 6 weeks with fructose were exposed to 15 min of ischemia and 30 min of reperfusion.

View Article and Find Full Text PDF

Background: Intralipid® administration at reperfusion elicits protection against myocardial ischemia-reperfusion injury. However, the underlying mechanisms are not fully understood.

Methods: Sprague-Dawley rat hearts were exposed to 15 min of ischemia and 30 min of reperfusion in the absence or presence of Intralipid® 1% administered at the onset of reperfusion.

View Article and Find Full Text PDF

Although evidence that type 2 diabetes mellitus (T2DM) is accompanied by mitochondrial dysfunction in skeletal muscle has been accumulating, a causal link between mitochondrial dysfunction and the pathogenesis of the disease remains unclear. Our study focuses on an early stage of the disease to determine whether mitochondrial dysfunction contributes to the development of T2DM. The fructose-fed (FF) rat was used as an animal model of early T2DM.

View Article and Find Full Text PDF

Aims: Infarct-remodelled hearts are less amenable to protection against ischaemia/reperfusion. Understanding preservation of energy metabolism in diseased vs. healthy hearts may help to develop anti-ischaemic strategies effective also in jeopardized myocardium.

View Article and Find Full Text PDF

Background: Mesenchymal stem cells (MSC) are self-renewing clonal progenitor cells of nonhematopoietic tissues that exhibit a marked tropism to wounds and tumors. The authors' studies aimed at exploring how local anesthetics would affect MSC biology.

Methods: Proliferation, colony formation, in vitro wound healing, and bone differentiation assays of culture-expanded bone-marrow-derived murine MSC were performed in the presence of increasing concentrations of lidocaine, ropivacaine, and bupivacaine.

View Article and Find Full Text PDF

Background: There is a lack of studies investigating cardioprotection by common combinations of anesthetics. However, because a general anesthetic consists of a mixture of drugs with potentially interfering effects on signaling and cytoprotection, the most favorable combination should be used.

Methods: Working rat hearts were exposed to 20 min of ischemia and 30 min of reperfusion.

View Article and Find Full Text PDF

Background: Secretion of insulin and glucagon is triggered by elevated intracellular calcium levels. Although the precise mechanism by which the calcium signal is coupled to insulin and glucagon granule exocytosis is unclear, synaptotagmin-7 has been shown to be a positive regulator of calcium-dependent insulin and glucagon secretion, and may function as a calcium sensor for insulin and glucagon granule exocytosis. Deletion of synaptotagmin-7 leads to impaired glucose-stimulated insulin secretion and nearly abolished Ca(2+)-dependent glucagon secretion in mice.

View Article and Find Full Text PDF