Enhanced fatty acid oxidation through Metformin and Baicalin as therapy for COVID-19 and associated inflammatory states in lung and kidney

Progressive respiratory failure is the primary cause of death in the coronavirus disease 2019 (COVID-19) pandemic. It is the final outcome of the acute respiratory distress syndrome (ARDS), characterized by an initial exacerbated inflammatory response and ultimate tissue scarring. Energy balance may be crucial for the recovery of clinical COVID-19. Hence, we asked if two key pathways involved in energy generation, AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signaling and fatty acid oxidation (FAO) could be beneficial. We tested the drugs Metformin (AMPk activator) and Baicalin (Cpt1A activator) in different experimental models mimicking COVID-19 associated inflammation in lung and kidney. We also studied two different cohorts of COVID19 patients that had been previously treated with Metformin. These drugs ameliorated lung damage in an ARDS animal model, while activation of AMPK/ACC signaling increased mitochondrial function and decreased TGF-beta-induced fibrosis, apoptosis and inflammation markers in lung epithelial cells. Similar results were observed with two new indole derivatives IND6 and IND8 with AMPK activating capacity. Consistently, a reduced stay in the intensive care unit was observed in COVID-19 patients previously exposed to Metformin. Baicalin also reduced kidney fibrosis in two animal models of kidney injury, another key target of COVID-19, while in vitro both drugs improved mitochondrial function and prevented TGF-beta-induced renal epithelial cell dedifferentiation. Our results support that strategies based on energy supply may prove useful in the prevention of COVID-19-induced lung and renal damage.Copyright © 2023

The use of alanine, free carnitine and IGFBP-1 as potential biomarkers for glycogen storage disease type I

Background: Glycogen Storage Disease Ia (GSDIa) and Ib (GSDIb) are inborn errors of carbohydrate metabolism due to a deficiency of glucose-6-phosphatase (G6Pase) or glucose-6-phosphate translocase (G6PT), respectively. Consuming prescribed amounts of uncooked cornstarch (UCCS) to prevent hypoglycemia is the standard of care for GSDIa and GSDIb. Patients followed in our GSD Program are admitted to the hospital annually for evaluation of their metabolic control by measuring glucose and lactate levels and revising treatment regimens accordingly. Lack of bed space due to the COVID-19 pandemic has created a need for alternate markers of metabolic control as lactate measurements are unreliable in the outpatient setting. This research aims to identify alternative biomarkers to show degree of metabolic control in individuals with GSDI. Method(s): A retrospective chart review was conducted on 45 adults and children with GSDI using data from January 1, 2014 toMay 6, 2021. Plasma alanine and free carnitine levels were compared with laboratory reference ranges. Results from the three tests were not available on every subject. Plasma alanine was evaluated on 24 subjects (16-GSDIa, 8-GSDIb) and free carnitine was evaluated on 25 subjects (17-GSDIa, 8-GSDIb). Result(s): Alanine levels in subjects with GSDIa ranged from 378 to 786 umol/L, while alanine levels in subjects with GSDIb ranged from 254 to 506 umol/L (reference range = 103-528 umol/L). Free carnitine levels ranged from26 to 72 umol/L in subjects with GSDIa and from 44 to 90 umol/L in subjects with GSDIb (reference range = 19-55 umol/L). Conclusion(s): Our analysis showed that plasma alanine and free carnitine have potential to be used as biomarkers of metabolic control. For plasma alanine, there seemed to be differences between subjects with GSDIa and GSDIb, as the majority of subjects with GSDIa had elevations in plasma alanine, while subjects with GSDIb did not. Elevated plasma alanine levels indicate lactic acidosis. For GSDIb, we hypothesize that there may be some type of G6Pase enzyme activity that occurs outside of the endoplasmic reticulum. When looking at both groups, free carnitine levels were mostly elevated. This indicates that there could be inhibition of fatty acid oxidation.Copyright © 2022 Elsevier Inc. All rights reserved.

Ketone Bodies and Cardiovascular Disease: An Alternate Fuel Source to the Rescue.

The increased metabolic activity of the heart as a pump involves a high demand of mitochondrial adenosine triphosphate (ATP) production for its mechanical and electrical activities accomplished mainly via oxidative phosphorylation, supplying up to 95% of the necessary ATP production, with the rest attained by substrate-level phosphorylation in glycolysis. In the normal human heart, fatty acids provide the principal fuel (40-70%) for ATP generation, followed mainly by glucose (20-30%), and to a lesser degree (<5%) by other substrates (lactate, ketones, pyruvate and amino acids). Although ketones contribute 4-15% under normal situations, the rate of glucose use is drastically diminished in the hypertrophied and failing heart which switches to ketone bodies as an alternate fuel which are oxidized in lieu of glucose, and if adequately abundant, they reduce myocardial fat delivery and usage. Increasing cardiac ketone body oxidation appears beneficial in the context of heart failure (HF) and other pathological cardiovascular (CV) conditions. Also, an enhanced expression of genes crucial for ketone break down facilitates fat or ketone usage which averts or slows down HF, potentially by avoiding the use of glucose-derived carbon needed for anabolic processes. These issues of ketone body utilization in HF and other CV diseases are herein reviewed and pictorially illustrated.

B Cells Fit for Germinal Center Activity Predict Response to a Third Dose of SARS-CoV-2 Vaccine in Solid Organ Transplant Recipients

Purpose: While SARS-CoV-2 vaccination has dramatically reduced COVID-19 severity in the general population, fully vaccinated solid organ transplant recipients (SOTRs) demonstrate reduced seroconversion and increased breakthrough infection rates. Furthermore, a third vaccine dose only increases antibody and T cell responses in a proportion of SOTRs. We sought to investigate the underlying mechanisms resulting in varied humoral responses in SOTRs. Method(s): Within a longitudinal prospective cohort of SOTRs, anti-spike IgG, total and spike-specific B cells were evaluated in 44 SOTR participants before and after a third vaccine dose using high dimensional flow cytometry to assess immunologic and metabolic phenotypes. B cell phenotypes were compared to those of 10 healthy controls who received a standard two-dose mRNA series. Result(s): Notably, even in the absence anti-spike antibody after two doses, spikespecific B cells were detectable in most SOTRs (76%). While 15% of participants were seropositive before the third dose, 72% were seropositive afterward. B cells, however, were differentially skewed towards non-class switched B cells in SOTRs as compared to healthy control B cells. Expansion of spike-specific class-switched B cells in SOTRs following a third vaccine dose correlated with increased classswitched (IgG) antibody titers. Antibody response to a third vaccine dose was associated with expanded populations of germinal center-like (CD10+CD27+) B cells, as well as CD11c+ alternative lineage B cells with specific upregulation of CPT1a, the rate limiting enzyme of fatty acid oxidation and a preferred energy source of germinal center B cells. Conclusion(s): This analysis defines a distinct B cell phenotype in SOTRs who respond to a third SARS-CoV-2 vaccine dose, specifically identifying fatty acid oxidation as pathway that could be targeted to improve vaccine response such as through targeted immunosuppressive modulation. (Figure Presented).

Triglyceride levels in COVID-19 patients during admission in intensive care correlate with disease severity and mortality

Introduction: It has been established that plasma triglyceride levels are raised during infection and inflammation, due to increased adipose tissue lipolysis, fatty acid synthesis and suppressed fatty acid oxidation.1 Increased triglycerides have also been linked to the 'cytokine storm' underlying the pathophysiology of coronavirus disease 2019 (COVID-19).2 Severe outcomes in COVID-19 patients have been found to be associated with higher triglyceride levels before the infection.3 Another study found triglycerides to be significantly higher after recovery than during the acute phase of infection.4 There is limited data on the trajectory of triglyceride levels in COVID-19 patients during admission in intensive care. Investigating whether triglyceride levels are a useful predictor of disease severity and mortality would enable earlier detection of high-risk patients. While triglyceride levels in COVID-19 patients with mild or severe infections were found to be elevated, this was not the case in those with critical illness which included respiratory or multiple organ failure and septic shock.5 The differences in lipid metabolism between COVID-19 patients and patients with critical illness are yet to be elucidated. Objectives: In this study, triglyceride levels of COVID-19 patients during admission in the general intensive care (GICU) were examined in relation to disease severity and mortality. Triglyceride levels at the beginning of hospitalisation were compared between GICU patients with COVID-19, acute respiratory distress syndrome (ARDS) and critical illness, and healthy controls. Methods: Data was obtained from medical records of 93 patients with COVID-19 admitted to GICU at University Hospital Southampton, between March 2020 and May 2020. Triglyceride levels were recorded for each day of hospitalisation. Data was also obtained from medical records of 8 critically ill patients, 10 patients with ARDS and 10 healthy volunteers. Results: The trajectory of triglyceride levels in this cohort of COVID-19 patients started low, then increased over the course of admission (Figure 1). Increased average triglyceride levels correlated with increased risk for severe disease outcome, as indicated by the Sequential Organ Failure Assessment (SOFA) score calculated at the beginning of GICU admission (p<0.05) (Figure 2). Increased triglyceride levels in the first week of GICU admission also correlated with mortality (p<0.05). When compared with healthy controls and patients admitted to GICU with ARDS, patients with COVID-19 and critical illness had raised triglycerides (Figure 3). Conclusions: Increased triglyceride levels in COVID-19 patients over the duration of GICU admission are associated with worse disease outcomes and increased mortality. This provides further evidence for the role of dyslipidaemia in the progression of COVID-19.

Differential Responses to Sigma-1 or Sigma-2 Receptor Ablation in Adiposity, Fat Oxidation, and Sexual Dimorphism.

Obesity is increasing at epidemic rates across the US and worldwide, as are its co-morbidities, including type-2 diabetes and cardiovascular disease. Thus, targeted interventions to reduce the prevalence of obesity are of the utmost importance. The sigma-1 receptor (S1R) and sigma-2 receptor (S2R; encoded by Tmem97) belong to the same class of drug-binding sites, yet they are genetically distinct. There are multiple ongoing clinical trials focused on sigma receptors, targeting diseases ranging from Alzheimer's disease through chronic pain to COVID-19. However, little is known regarding their gene-specific role in obesity. In this study, we measured body composition, used a comprehensive laboratory-animal monitoring system, and determined the glucose and insulin tolerance in mice fed a high-fat diet. Compared to Sigmar1+/+ mice of the same sex, the male and female Sigmar1-/- mice had lower fat mass (17% and 12% lower, respectively), and elevated lean mass (16% and 10% higher, respectively), but S1R ablation had no effect on their metabolism. The male Tmem97-/- mice exhibited 7% lower fat mass, 8% higher lean mass, increased volumes of O2 and CO2, a decreased respiratory exchange ratio indicating elevated fatty-acid oxidation, and improved insulin tolerance, compared to the male Tmem97+/+ mice. There were no changes in any of these parameters in the female Tmem97-/- mice. Together, these data indicate that the S1R ablation in male and female mice or the S2R ablation in male mice protects against diet-induced adiposity, and that S2R ablation, but not S1R deletion, improves insulin tolerance and enhances fatty-acid oxidation in male mice. Further mechanistic investigations may lead to translational strategies to target differential S1R/S2R regulations and sexual dimorphism for precision treatments of obesity.

Alterations in the Covid-19 - Associated Proteome Relative to Length of Hospital Stay

RATIONALE: The proteomic responses of hospitalized patients with SARS Co-V-2 infection may provide insight into risk, time course, and mechanisms associated with this infection. We used a high throughput proteomic platform to examine proteins that were differentially expressed relative to the length of hospital stay (LOS). METHOD:26 patients, hospitalized with SARS CoV-2 infection (mean age 48 yrs, 44% women) had blood samples obtained within 72 hours of admission. Initial plasma samples were analyzed from patients who were hospitalized for < 3 days (n=6), < 7days (n=12) and > 7 days (n=8) of LOS and compared to healthy controls (HC, n=8). Samples were analyzed with the modified aptamer-based array (SomaScan) that measures more than 7,000 human proteins representing different molecular pathways and gene families. Differentially regulated proteins with > 1.5 fold change and a false discovery rate of 5% were analyzed using the Ingenuity Pathway Analysis (IPA). Unique protein categories associated with LOS were assessed. RESULT: Compared to HC, differentially expressed proteins were detected among the 3 groups: 461 at < 3 days, 1,635 proteins at < 7 days and 1,738 proteins in >7 days. 407 proteins were common among all hospitalized COVID 19 individuals independent of LOS and 12, 250 and 361 proteins were uniquely present at < 3 days, < 7 days and > 7 days respectively compared to HC. The table below demonstrates the top highly enriched canonical pathway, molecular function and upstream regulator of differentially expressed proteins. The temporal sequence of these protein networks varied with LOS. Representative examples include early responses;platelet membrane glycoprotein GP6 signaling pathway that involves the FcR gamma-chain and the Src kinases linked to platelet aggregation, signaling involved in T cell receptor-mediated IL-2 production (TEC kinase). Less than 7 days include diacylglycerol associated with T cell activation, carnitine palmitoyltransferase associated with mitochondrial beta-oxidation of long chain fatty acids. CXCR4 a receptor for stromal -cell derived factor 1 and associated with COVID-19 prognosis. Late responses after 7 days include pathways involved in remodeling of epithelial adherens junctions. CONCLUSIONS : A high throughput proteomic approach provides insight into the dynamic regulation of protein pathways associated with the progression of SARS-Co-V2 infection. This may provide additional insight into risk and mechanisms associated with outcomes in COVID. (Table Presented).

POS-092 SGLT2 INHIBITOR – INDUCED EUGLYCEMIC DIABETIC KETOACIDOSIS IN GUILLAIN-BARRE SYNDROME: A CASE REPORT

Introduction: Introduction: Euglycemic diabetic ketoacidosis (EuDKA) is a rare but increasingly reported serious adverse effect of SGLT2 inhibitors. There is not much published literature on the incidence of EuDKA and the factors associated with it. Though SGLT2 inhibitors were introduced as glucose lowering agents, recent trials have demonstrated their favourable cardiovascular outcome in heart failure and ability to retard progression of proteinuric kidney disease, including in non-diabetics. Hence use of this class of drugs is anticipated to increase exponentially, given the combined high global burden of diabetes, coronary artery disease and chronic kidney disease. As we embark to use the SGLT2 inhibitors in different clinical scenarios, it becomes imperative to report their adverse effects encountered in uncommon clinical conditions as well. Methods: Case history: A 42-year-old gentleman with history of type 2 diabetes mellitus for 15 years and coronary artery disease, presented with difficulty in climbing stairs and walking for 5 days with progressive difficulty in getting up from bed. He did not have past history of covid infection and had been immunised with 1 dose of covid vaccine. On examination, patient had normal hemodynamics. There was flaccid quadriparesis with areflexia and truncal muscle weakness. Nerve conduction study confirmed acute demyelinating polyradiculoneuropathy. His baseline laboratory investigations revealed normal renal parameters but metabolic acidosis was noted at the time of admission. Patient was started on iv immunoglobulin 2mg/kg and the motor weakness improved from grade 2/5 to 4/5. However, the high anion gap metabolic acidosis worsened over the next 4 days and patient developed acidotic breathing. His sugars were within normal limits and the patient was on metformin, glimeperide, vildagliptin, voglibose and dapagliflozin. As blood lactate levels were normal with urine acetone positivity, euglycemic diabetic ketoacidosis secondary to SGLT2 inhibitor was suspected and all the oral hypoglycemic agents were stopped. He was started on hydration and insulin infusion. After 48 hours of stopping dapagliflozin, acidosis resolved completely and the patient was reintroduced back on the other 4 class drugs. At follow-up, there was no recurrence of acidosis and patient was able to walk with support and physiotherapy. [Formula presented] Results: Discussion: SGLT2 inhibitors cause glycosuria and directly induce glucagon release from pancreas. Combined with insulin deficiency, this results in lipolysis, fatty acid oxidation and ketogenesis. They also cause increased renal reabsorption of ketone bodies. The precipitating factors for EuDKA identified so far include abrupt reduction in insulin dosage, reduced oral intake, infections, surgery, excess alcohol use, volume depletion, type 1 diabetes and heavy physical exercise. This is the first reported case of SGLT2 inhibitor-induced EuDKA in a patient with Guillain-Barre syndrome. As symptoms of dehydration may not be significant due to lack of hyperglycemia in EuDKA, there may be a delay in the diagnosis of this complication. Conclusions: Conclusion: The possibility of EuDKA to be kept in mind while evaluating metabolic acidosis in a diabetic patient on SGLT2 inhibitors. Temporarily withholding the SGLT2 inhibitors during an intercurrent illness will prevent the occurrence of the above serious adverse effect. No conflict of interest

Low-Grade Chronic Inflammation: Lifestyle Management

Low-grade chronic inflammation (LGCI) may be managed by lifestyle measures that focus on adipose tissue and the intestine as both contain many immune cells, es-pecially macrophages. The aim regarding adipose tissue is to induce a chronically high fatty acid oxidation rate or prevent increases in fat mass. The former may be achieved by adhering to the minimum amount of physical activity necessary for health maintenance. However, increased fat mass already present often requires weight reduction, which is achieved most effectively by meal replacement. Short-chain fatty acids produced by intestinal microbiota modulate inflammatory potential in the intestine by acting on the intestinal wall and at systemic level. Dietary fibre forms the main substrate for the microbiota, so low fibre intake results in low short-chain fatty acid production and compromised homeostasis. The Mediterranean diet is held to be an ideal alimentary measure in combating LGCI due to the diet’s anti-inflammatory effects and sub-stantial amounts of dietary fibre. Other factors such as sleep and stress also affect LGCI, but to what extent compared to adipose tissue and the intestine remains unclear. Controlling LGCI will likely reduce the risk of severe COVID-19-like and non-communicable disease, warranting routine LGCI analysis.

Fatal COVID-19 infection in a patient with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency: A case report.

Long-chain fatty-acyl CoA dehydrogenase deficiency (LCHADD) is an inborn error of long chain fatty acid oxidation with various features including hypoketotic hypoglycemia, recurrent rhabdomyolysis, pigmentary retinopathy, peripheral neuropathy, cardiomyopathy, and arrhythmias. Various stresses trigger metabolic decompensation. Coronavirus disease 2019 (COVID-19) is a pandemic caused by the RNA virus SARS-CoV-2 with diverse presentations ranging from respiratory symptoms to myocarditis. We report a case of a patient with LCHADD who initially presented with typical metabolic decompensation symptoms including nausea, vomiting, and rhabdomyolysis in addition to mild cough, and was found to have COVID-19. She developed acute respiratory failure and refractory hypotension from severe cardiomyopathy which progressed to multiple organ failure and death. Our case illustrates the need for close monitoring of cardiac function in patients with a long-chain fatty acid oxidation disorder.