HYPOCHOLESTEROLEMIA IN CLINICALLY SERIOUS CONDITIONS - REVIEW

Cholesterol levels as a predictive marker for ICU survival in patients with cardiogenic shock supported by VenoArterial ExtraCorporeal membrane oxygenation

BackgroundVeno-Arterial Extracorporeal Life Support (VA ECMO) is a critical intervention for patients with cardiogenic shock, serving as bridge to recovery, transplantation, or long-term therapies. The complexity of VA ECMO and its associated risks underscore the need for reliable prognostic markers to guide patient management. This study aimed to evaluate whether cholesterol levels could serve as a specific marker for ICU survival in patients with cardiogenic shock treated with VA ECMO.MethodsA retrospective observational study was conducted at Catharina Hospital Eindhoven, The Netherlands, between January 2013 and November 2019. Data from 67 patients treated with VA ECMO were analyzed. Cholesterol levels were measured daily from day 1 to day 5 after VA ECMO initiation. Demographic data, comorbidities, and outcomes were extracted from the patient data management system. Statistical analysis was performed, with a focus on non-normality of data distribution and the predictive value of cholesterol levels on ICU survival.ResultsThe study identified a significant association between higher cholesterol levels on the first day of VA ECMO treatment and increased ICU survival. A cholesterol threshold of 2.0 mmol/L was found to be an independent predictor of survival, with patients above this threshold having a higher survival rate. Multivariate logistic regression analysis confirmed the significance of this cholesterol threshold in predicting ICU survival.ConclusionCholesterol levels measured on the first day after the initiation of VA ECMO are a significant indicator of ICU survival in patients with cardiogenic shock. A threshold of 2.0 mmol/L is particularly predictive, offering a potential prognostic tool for clinicians managing these critically ill patients.

Total cholesterol and bilirubin levels are associated with neurologic outcomes in patients with out-of-hospital cardiac arrest

BACKGROUND

Assessing the neurologic outcomes of patients who experience out of hospital cardiac arrest (OHCA) is challenging. Neurologic outcomes were evaluated using initial nutrition related biochemical markers.

METHODS

We used data from a multicentre retrospective observational study, the Korean Cardiac Arrest Resuscitation Consortium (KoCARC) registry. Among the 666 patients, 217 had good neurologic outcomes, while 449 had poor neurologic outcomes. Multivariate logistic regression and classification and regression tree (CART) analyses were employed.

RESULT

In the multivariate logistic regression analysis, total cholesterol ≥ 158.5 mg/dL, total bilirubin ≥ 0.265 mg/dL, Sodium < 142.1 mEq/L, AST < 200.5 U/L and were identified as significant biomarkers for good neurologic outcomes. In the CART analysis, total cholesterol ≥ 158.5 mg/dL and total bilirubin ≥ 0.365 mg/dL were found to be significant indicators. In additional analysis, when the total bilirubin level ranged from 0.6 to 0.7 mg/dL, the highest rate of a good neurologic outcome was observed at 44.6%, whereas levels below or above this range gradually indicated a lower rate of a good neurologic outcome.

CONCLUSION

We propose that total cholesterol and total bilirubin levels could serve as valuable indicators for predicting neurologic outcomes in patients with OHCA.

Cholesterol mediated ferroptosis suppression reveals essential roles of Coenzyme Q and squalene

Recent findings have shown that fatty acid metabolism is profoundly involved in ferroptosis. However, the role of cholesterol in this process remains incompletely understood. In this work, we show that modulating cholesterol levels changes vulnerability of cells to ferroptosis. Cholesterol alters metabolic flux of the mevalonate pathway by promoting Squalene Epoxidase (SQLE) degradation, a rate limiting step in cholesterol biosynthesis, thereby increasing both CoQ10 and squalene levels. Importantly, whereas inactivation of Farnesyl-Diphosphate Farnesyltransferase 1 (FDFT1), the branch point of cholesterol biosynthesis pathway, exhibits minimal effect on ferroptosis, simultaneous inhibition of both CoQ10 and squalene biosynthesis completely abrogates the effect of cholesterol. Mouse models of ischemia-reperfusion and doxorubicin induced hepatoxicity confirm the protective role of cholesterol in ferroptosis. Our study elucidates a potential role of ferroptosis in diseases related to dysregulation of cholesterol metabolism and suggests a possible therapeutic target that involves ferroptotic cell death.

Life-Limiting Peripheral Organ Dysfunction in Feline Sandhoff Disease Emerges after Effective CNS Gene Therapy

OBJECTIVE

GM2 gangliosidosis is usually fatal by 5 years of age in its 2 major subtypes, Tay-Sachs and Sandhoff disease. First reported in 1881, GM2 gangliosidosis has no effective treatment today, and children succumb to the disease after a protracted neurodegenerative course and semi-vegetative state. This study seeks to further develop adeno-associated virus (AAV) gene therapy for human translation.

METHODS

Cats with Sandhoff disease were treated by intracranial injection of vectors expressing feline β-N-acetylhexosaminidase, the enzyme deficient in GM2 gangliosidosis.

RESULTS

Hexosaminidase activity throughout the brain and spinal cord was above normal after treatment, with highest activities at the injection sites (thalamus and deep cerebellar nuclei). Ganglioside storage was reduced throughout the brain and spinal cord, with near complete clearance in many regions. While untreated cats with Sandhoff disease lived for 4.4 ± 0.6 months, AAV-treated cats lived to 19.1 ± 8.6 months, and 3 of 9 cats lived >21 months. Correction of the central nervous system was so effective that significant increases in lifespan led to the emergence of otherwise subclinical peripheral disease, including megacolon, enlarged stomach and urinary bladder, soft tissue spinal cord compression, and patellar luxation. Throughout the gastrointestinal tract, neurons of the myenteric and submucosal plexuses developed profound pathology, demonstrating that the enteric nervous system was inadequately treated.

INTERPRETATION

The vector formulation in the current study effectively treats neuropathology in feline Sandhoff disease, but whole-body targeting will be an important consideration in next-generation approaches. ANN NEUROL 2023;94:969-986.

Nutrition and Outcome of 100 Endoscopic Gastrostomy-Fed Citizens with Severe Dementia

Dementia is a rising public health concern. Feeding and nutritional problems increase as the disease progresses, affecting the clinical course and caregiver burden. While some guidelines advise against percutaneous endoscopic gastrostomy (PEG) and tube feeding in advanced dementia, conflicting evidence exists. This study aims to evaluate the nutritional status and influence of PEG feeding on the outcome and evolution of nutritional/prognosis markers of patients with severe dementia (PWSD) who underwent gastrostomy for nutritional support. We conducted a 16-year retrospective study on 100 PEG-fed PWSD with strong familial support. We evaluated the survival PEG-feeding period, safety, and objective nutritional/prognosis data on the gastrostomy day and after 3 months: Body Mass Index (BMI), Mid Upper Arm Circumference, Tricipital Skinfold, Mid-Arm Muscle Circumference, albumin, transferrin, total cholesterol, and hemoglobin. Most patients presented low values in these nutritional/prognosis parameters. No major life-threatening PEG complications were reported. The mean survival time after gastrostomy was 27.9 months (median of 17 months). Female sex, BMI recovery at 3 months, and higher baseline hemoglobin levels were associated with a reduced risk of death and increased survival time. The study concluded that, in carefully selected PWSD with strong familial support, PEG feeding can improve nutritional status and have a positive impact on survival.

Malnutrition, Cancer Stage and Gastrostomy Timing as Markers of Poor Outcomes in Gastrostomy-Fed Head and Neck Cancer Patients

For percutaneous endoscopic gastrostomy (PEG)-fed head and neck cancer (HNC) patients, risk markers of poor outcomes may identify those needing more intensive support. This retrospective study aimed to evaluate markers of poor outcomes using TNM-defined stages, initial anthropometry [body mass index (BMI), mid-upper arm circumference (MUAC), tricipital skinfold (TSF), mid-arm muscle circumference (MAMC)] and laboratory data (albumin, transferrin, cholesterol), with 138 patients, 42-94 years old, enrolled. The patients had cancer, most frequently in the larynx (n = 52), predominantly stage IV (n = 109). Stage IVc presented a four times greater death risk than stage I (OR 3.998). Most patients presented low parameters: low BMI (n = 76), MUAC (n = 114), TSF (n = 58), MAMC (n = 81), albumin (n = 47), transferrin (n = 93), and cholesterol (n = 53). In stages I, III, IVa, and IVb, MAMC and PEG-timing were major survival determinants. Each MAMC unit increase resulted in 16% death risk decrease. Additional 10 PEG-feeding days resulted in 1% mortality decrease. Comparing IVa/IVb vs. IVc, albumin and transferrin presented significant differences (p = 0.042; p = 0.008). All parameters decreased as severity of stages increased. HNC patients were malnourished before PEG, with advanced cancer stages, and poor outcomes. Initial MAMC, reflecting lean tissue, significantly increases survival time, highlighting the importance of preserving muscle mass. PEG duration correlated positively with increased survival, lowering death risk by 1% for every additional 10 PEG-feeding days, signaling the need for early gastrostomy.

Early postoperative serum albumin levels as predictors of surgical outcomes in head and neck squamous cell carcinoma

BACKGROUND

Malnutrition is a common issue in patients with head and neck squamous cell carcinoma and has a negative effect on surgical outcomes.

OBJECTIVE

We attempted to determine which malnutrition diagnostic variables can be used as predictors of postoperative complications in patients with head and neck squamous cell carcinoma.

METHODS

Forty-one patients undergoing surgery for head and neck squamous cell carcinoma were submitted to a prospective evaluation. Biochemical data, anthropometric measurements and evaluation of body composition were used in the nutritional analysis.

RESULTS

Twenty-two patients (53.6%) developed complications. Serum albumin measured on the first postoperative day was the only variable that significantly differed between groups. A cut-off value of 2.8 g/dL distinguished between patients with a complicated and uncomplicated postoperative course. Normalization of albumin levels occurred more frequently and more rapidly in the noncomplicated group.

CONCLUSION

Serum albumin measured on the first postoperative day was the only variable that was a predicter of postoperative complications after major head and neck squamous cell carcinoma surgery.

Correlation between early changes of serum lipids and clinical severity in patients with wasp stings

BACKGROUND

Wasp stings are a serious problem worldwide, and patients in severe cases may experience multi-organ failure. However, the mechanism of hypolipidemia in patients with wasp stings is unknown.

OBJECTIVE

To investigate the relationship between early changes in lipid levels and clinical severity and the possible underlying mechanisms.

METHODS

A retrospective analysis of 212 patients (mild: 77; moderate: 50; severe: 85) with wasp stings was conducted. Clinical data, including lipid test results within 24 h of admission, were analysed. A total of 1060 healthy age- and gender-matched controls were used.

RESULTS

Patients with wasp stings had lower lipid levels than healthy controls (P<0.01). Lipid levels decreased with disease severity, except for triglycerides (P<0.05). The number of stings, degree of organ failure, need for mechanical ventilation and extracorporeal blood purification, and mortality were higher in the severe group than in the mild and moderate groups (P<0.01). A decrease in lipid levels was accompanied by an increase in inflammatory indicators. In the severe group, a reduction in lipid levels was associated with ventilator application and blood purification, independent of survival status.

CONCLUSIONS

Patients with wasp stings experience a reduction in lipid levels, which is related to the severity of clinical manifestations. Early lipid levels may serve as a simple indicator for the severity of wasp stings, and targeting lipid metabolism may be a novel treatment.

Low total cholesterol predicts early death in children with hemophagocytic lymphohistiocytosis

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rapidly progressive and potentially life-threatening disorder. Identifying risk factors and timely adjustment of the given treatment regimens is critical to reducing the early mortality in HLH patients. Hypocholesterolemia has been reported to be associated with poor prognosis in a variety of critical illnesses. However, serum cholesterol is rarely studied in HLH patients, and its prognostic value is unclear.

METHODS

We conducted a retrospective cohort study in National Clinical Research Center for Child Health and Disorders (Chongqing), identifying pediatric HLH patients (including genetically confirmed pHLH and not genetically confirmed pHLH) diagnosed with the HLH-2004 protocol and treated with immunochemotherapy between January 2008 and December 2020. The patients' blood lipid levels at initial diagnosis of HLH, including triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), were reviewed based on electronic medical records. Both Cox and logistic regression models were used to estimate the effects of blood lipid indicators on early death (within 30 days after diagnosis).

RESULTS

A total of 353 patients were enrolled in the study, with a median age at diagnosis of 45 months. The observed 30-day mortality rate was 19.05% (64/336, 17 were lost to follow-up) and Kaplan-Meier-estimated 3-year survival rate was 61.67% (95% CI, 56.27%-67.59%). DNA-targeted sequencing of HLH-related genes was performed in 173 (49.0%, 173/353) patients (not all patients with suspected pHLH underwent genetic testing), and 29 patients were diagnosed with genetically confirmed pHLH. Lipid panel was performed in 349 patients: 91.98% (321/349) had TG ≥ 1.80 mmol/L, 62.75%(219/349) had TG ≥ 3.00 mmol/L, 92.84% (324/349) had HDL-C ≤ 1.04 mmol/L, 58.74% (205/349) had LDL-C ≤ 1.30 mmol/L and 24.64% (86/349) had TC ≤ 3.11 mmol/L. TC ≤ 3.11 mmol/L and BUN ≥ 7.14 mmol/L were the independent risk factors for 30-day mortality [HR(95%CI): 2.85(1.46, 5.57) and 2.90(1.48, 5.68), respectively]. The presence of one of these risk factors increased the 30-day mortality rate by 6-fold [HR = 6.24, 95%CI: (3.18, 12.22)] and the presence of two risk factors by nearly 10-fold [HR = 9.98, 95%CI: (4.23, 23.56)] compared with the patients with no risk factors.

CONCLUSION

Severe derangement of lipoproteins is common in children with HLH, and decreased TC is an independent risk factor for early death. Hypocholesterolemia should be included as a biomarker during the diagnosis and management of HLH patients.

Characterising the relationships between physiological indicators and all-cause mortality (NHANES): a population-based cohort study

BACKGROUND

Mortality risk stratification based on dichotomising a physiological indicator with a cutoff point might not adequately capture increased mortality risk and might not account for non-linear associations. We aimed to characterise the linear and non-linear relationships of 27 physiological indicators with all-cause mortality to evaluate whether the current clinical thresholds are suitable in distinguishing patients at high risk for mortality from those at low risk.

METHODS

For this observational cohort study of the US non-institutionalised population, we used data from adults (≥18 years) included in the 1999-2014 National Health and Nutrition Examination Survey (NHANES) linked with National Death Index mortality data collected from Jan 1, 1999, up until Dec 31, 2015. We used Cox proportional hazards regression models adjusted for age, sex, and race or ethnicity to assess associations of physiological indicators with all-cause mortality. We assessed non-linear associations by discretising the physiological indicator into nine quantiles (termed novemtiles) and by using a weighted sum of cubic polynomials (spline). We used ten-fold cross validation to select the most appropriate model using the concordance index, Nagelkerke R2, and Akaike Information Criterion. We identified the level of each physiological indicator that led to a 10% increase in mortality risk to define our cutoffs used to compare with the current clinical thresholds.

FINDINGS

We included 47 266 adults of 82 091 assessed for eligibility. 25 (93%) of 27 indicators showed non-linear associations with substantial increases compared with linear models in mortality risk (1·5-2·5-times increase). Height and 60 s pulse were the only physiological indicators to show linear associations. For example, participants with an estimated glomerular filtration rate (GFR) of less than 65 mL/min per 1·73 m2 or between 90-116 mL/min per 1·73 m2 are at moderate (hazard ratio 1-2) mortality risk. Those with a GFR greater than 117 mL/min per 1·73 m2 show substantial (hazard ratio ≥2) mortality risk. Both lower and higher values of cholesterol are associated with increased mortality risk. The current clinical thresholds do not align with our mortality-based cutoffs for fat deposition indices, 60 s pulse, triglycerides, cholesterol-related indicators, alkaline phosphatase, glycohaemoglobin, homoeostatic model assessment of insulin resistance, and GFR. For these indicators, the misalignment suggests the need to consider an additional bound when only one is provided.

INTERPRETATION

Most clinical indicators were shown to have non-linear associations with all-cause mortality. Furthermore, considering these non-linear associations can help derive reliable cutoffs to complement risk stratification and help inform clinical care delivery. Given the poor alignment with our proposed cutoffs, the current clinical thresholds might not adequately capture mortality risk.

Prospective Analysis of Lipid Variations in Hyperthyroid Subjects from Lahore, Pakistan

Perturbations in the actions of T3 and T4 influence the normal metabolic pathways. Responsiveness of lipid biomarkers like LDL-C, HDL-C, TC, TG, Apo-A, and Apo-B after rehabilitation of thyroid profile attaining euthyroid state was determined. A total of 179 age-matched subjects of both genders were recruited for this research. Sixty healthy controls, thirty-four subclinical, fifty overt hyperthyroid, and thirty-five follow-up subjects having 3 months of Carbimazole therapy were enrolled. Biochemical analysis was performed by chemistry analyzer, RIA, and ELISA. One-way ANOVA was applied for the statistical analysis, while significance (P < 0.05) of means was compared by the Student-Newman-Keuls (SNK) test. Pronounced reduction (P < 0.001) of cholesterol in overt as compared to control and subclinical was noticed, whereas marked improvement (P < 0.001) was evidenced in follow-up. Prominent elevation (P < 0.05) of TG in follow-up was evidenced as compared to control. Overt presented marked reduction of HDL-C as compared to subclinical and control (P < 0.01 and P < 0.001), respectively. Pronounced elevation (P < 0.001) of HDL-C was evidenced after treatment. Overt presented reduction of LDL-C as compared to subclinical and control (P < 0.01 and P < 0.05, respectively). The follow-up group demonstrated considerable (P < 0.001) improvement of LDL-C after treatment and elevation (P < 0.05) as compared to control. Overt presented reduction of Apo-B as compared to subclinical and control (P < 0.05 and P < 0.001, respectively). Improvement (P < 0.05) of Apo-B was evidenced in follow-up. Reduction (P < 0.05) of Apo-A in overt as compared to control and elevation (P < 0.05) in follow-up as compared to overt was evidenced. Conclusively, improvement after treatment was evidenced in lipid profile.

Alteration of lipid profile and value of lipids in the prediction of the length of hospital stay in COVID-19 pneumonia patients

To observe lipid profiles and their alterations in hospitalized patients with COVID-19 pneumonia (NCP) and evaluate the value of lipids for the prediction of the length of hospital stay (LOS), a total of 248 patients aged 18 years or older were enrolled in this retrospective study. At admission, the median levels of triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) in all patients were 1.11, 4.00, 0.89, and 2.11 mmol/L, respectively. Compared with common cases (n = 174), severe cases (n = 74) exhibited higher TG and HDL-C, and lower LDL-C. Levels of TC and LDL-C were negatively correlated with LOS. In 68 severe cases, serum lipids were followed up during hospitalization, and the median LOS was 29 days. The average levels of serum lipids were lowest at admission and gradually increased during hospitalization. Compared with the LOS ≤ 29 days group, serum levels of TC, HDL-C, and LDL-C were significantly lower in the LOS > 29 days group at admission; this lower trend was found in the subsequent tests for TC and LDL-C but not for HDL-C or TG. Multiple-variant COX regression showed that levels of TC or LDL-C at admission were independent risk of LOS prolongation. Together, these findings suggest that in patients with NCP, levels of TC and LDL-C at admission were negatively correlated with LOS. In severe cases, the gradual increase in TC, LDL-C, and HDL-C during hospitalization might indicate gradual recovery. TC < 3.75 mmol/L or LDL-C < 1.7 mmol/L at admission may act as an independent predictor of prolonged LOS.

Gene expression profiling of sepsis-associated acute kidney injury

Sepsis accounts for more than 50% of all acute kidney injury (AKI) cases, and the combination of sepsis and AKI increases the risk of mortality from sepsis alone. However, to the best of our knowledge, the specific mechanism by which sepsis causes AKI has not yet been fully elucidated, and there is no targeted therapy for sepsis-associated AKI (SA-AKI). The present study investigated gene expression profiles using RNA sequencing (RNA-Seq) and bioinformatics analyses to assess the function of differentially expressed genes (DEGs) and the molecular mechanisms relevant to the prognosis of SA-AKI. From the bioinformatics analysis, 2,256 downregulated and 3,146 upregulated genes were identified (false discovery rate <0.1 and fold-change >2). Gene Ontology analysis revealed that the genes were enriched in cellular metabolic processes, cell death and apoptosis. The enriched transcription factors were v-rel reticuloendotheliosis viral oncogene homolog A and signaling transducer and activator of transcription 3. The enriched microRNAs (miRNAs or miRs) among the DEGs were miR-30e, miR-181a, miR-340, miR-466d and miR-466l. Furthermore, the enriched pathways included toll-like receptor signaling, nod-like receptor signaling and the Janus kinase/STAT signaling pathway. In conclusion, the present study identified certain prognosis-related genes, transcription factors, miRNAs and pathways by analyzing gene expression profiles of SA-AKI using RNA-Seq, which provides some basis for future experimental studies.

Identification and Functional Annotation of Genes Related to Horses' Performance: From GWAS to Post-GWAS

Simple Summary

It is assumed that the athletic performance of horses is influenced by a large number of genes; however, to date, not many genomic studies have been performed to identify candidate genes. In this study we performed a systematic review of genome-wide association studies followed by functional analyses aiming to identify the most candidate genes for horse performance. We were successful in identifying 669 candidate genes, from which we built biological process networks. Regulatory elements (transcription factors, TFs) of these genes were identified and used to build a gene–TF network. Genes and TFs presented in this study are suggested to play a role in the studied traits through biological processes related with exercise performance, for example, positive regulation of glucose metabolism, regulation of vascular endothelial growth factor production, skeletal system development, cellular response to fatty acids and cellular response to lipids. In general, this study may provide insights into the genetic architecture underlying horse performance in different breeds around the world.

Abstract

Integration of genomic data with gene network analysis can be a relevant strategy for unraveling genetic mechanisms. It can be used to explore shared biological processes between genes, as well as highlighting transcription factors (TFs) related to phenotypes of interest. Unlike other species, gene–TF network analyses have not yet been well applied to horse traits. We aimed to (1) identify candidate genes associated with horse performance via systematic review, and (2) build biological processes and gene–TF networks from the identified genes aiming to highlight the most candidate genes for horse performance. Our systematic review considered peer-reviewed articles using 20 combinations of keywords. Nine articles were selected and placed into groups for functional analysis via gene networks. A total of 669 candidate genes were identified. From that, gene networks of biological processes from each group were constructed, highlighting processes associated with horse performance (e.g., regulation of systemic arterial blood pressure by vasopressin and regulation of actin polymerization and depolymerization). Transcription factors associated with candidate genes were also identified. Based on their biological processes and evidence from the literature, we identified the main TFs related to horse performance traits, which allowed us to construct a gene–TF network highlighting TFs and the most candidate genes for horse performance.

Prognostic value of dyslipidemia for sick dogs hospitalized in the intensive care unit of a veterinary teaching hospital

OBJECTIVE To evaluate the lipidemia status and serum concentrations of cholesterol and triglycerides of dogs when initially examined for hospitalization in the intensive care unit (ICU) of a veterinary teaching hospital and to determine whether these variables were predictive of survival to hospital discharge. DESIGN Retrospective cohort study. ANIMALS 549 client-owned sick (n = 398) and healthy (151) dogs. PROCEDURES Medical records of sick dogs hospitalized in the ICU at a veterinary teaching hospital between January 1, 2012, and September 30, 2015, and of healthy dogs evaluated at the teaching hospital during the same time frame were reviewed. Data collection included signalment, results of initial physical and clinicopathologic examinations, treatments, diagnosis, and survival to hospital discharge. Lipidemia status and serum concentrations of cholesterol and triglycerides were compared between healthy and sick dogs and between sick dogs that did and did not survive to hospital discharge. Regression analysis was performed to determine whether these variables were predictive of survival to hospital discharge in dogs. RESULTS Factors associated with increased odds of sick dogs not surviving to hospital discharge were hypocholesterolemia (OR, 1.87; 95% confidence interval [CI], 1.04 to 3.34), hypertriglyceridemia (OR, 3.20; 95% CI, 2.00 to 5.13), and concurrent hypocholesterolemia and hypertriglyceridemia (OR, 55.7; 95% CI, 3.2 to 959.6) at the time of initial evaluation. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that hypocholesterolemia and hypertriglyceridemia, alone or in combination, at initial examination were negative prognostic indicators for survival of dogs hospitalized in the ICU and that these conditions were easily identified with routine serum clinicopathologic analyses. (J Am Vet Med Assoc 2019;254:699-709).

Comparison of nutritional screening tools to assess nutritional risk and predict clinical outcomes in Mexican patients with digestive diseases

BACKGROUND

The prevalence of malnutrition remains high in hospitals but no "gold standard" has been established to identify nutritional risks adequately. The Nutrition Risk Screening-2002 (NRS-2002), Subjective Global Assessment (SGA), and Controlling Nutritional Status Index (CONUT) are widely used screening tools, but their efficacy has not yet been compared in Mexican patients. Here, we aimed to compare the efficacy of these tools in identifying nutritional risks within the first 48 h of admission in a group of patients with gastrointestinal diseases.

METHODS

This was a cross-sectional study of 196 patients. The results of the screening tools, length of hospital stay, serum albumin and cholesterol concentrations, lymphocyte counts, age, body mass index (BMI), complications, and mortality were analyzed. Kappa (κ) statistics were applied to determine the degree of agreement between tools. The performances of the screening tools in predicting complications and mortality were assessed using binary logistic regression.

RESULTS

The NRS-2002, SGA, and CONUT tools identified nutritional risk in 67, 74, and 51% of the patients, respectively. The observed agreements between tools were: NRS2002/SGA, κ = 0.53; CONUT/NRS-2002, κ = 0.42; and SGA/CONUT, κ = 0.36. Within age groups, the best agreement was found in those aged 51-65 years (κ = 0.68). CONUT and length of stay were both predictive for the number of complications. The number of complications and serum cholesterol concentrations were predictive for mortality.

CONCLUSIONS

The proportion of patients identified as having nutritional risk was high using all three screening tools. SGA, NRS-2002, and CONUT had similar capacities for screening risk, but the best agreement was observed between NRS-2002 and SGA. Only CONUT predicted complications, but none of these tools performed well in predicting mortality.

Hypocholesterolaemia and mortality in patients with coronary artery disease

BACKGROUND

The association between hypocholesterolaemia and outcome of patients with coronary artery disease (CAD) remains controversial. We undertook this study to investigate whether there is an association between spontaneous or under statin therapy occurring hypocholesterolaemia and mortality in patients with CAD.

MATERIALS AND METHODS

This study included 14 952 patients with CAD undergoing percutaneous coronary intervention (PCI). Hypocholesterolaemia was defined as a total cholesterol (TC) <157 mg/dL (the upper limit of 1st quintile of TC). The study outcome was all-cause mortality at 30 days and 3 years after PCI.

RESULTS

Patients are categorized in four groups according to TC and statin therapy on admission: statin-naïve patients with hypocholesterolaemia (n = 1102), statin-naïve patients without hypocholesterolaemia (n = 7490), statin-treated patients with hypocholesterolaemia (n = 1824) and statin-treated patients without hypocholesterolaemia (n = 4536). In these groups, 30-day all-cause deaths occurred in 3.7%, 1.4%, 1.2% and 0.6% of the patients, respectively; 3-year deaths occurred in 18.0%, 8.4%, 10.9% and 7.2%, of the patients, respectively. After adjustment, hypocholesterolaemia remained independently associated with 30-day (adjusted hazard ratio [HR] = 1.50, 95% confidence interval [CI] 1.07 to 2.09; P < 0001) and 3-year (HR = 1.29 [1.12-1.47]; P < .001) mortality. Statin therapy on admission was independently associated with 30-day (HR = 0.61 [0.43-0.86]; P = .012) and 3-year (HR = 0.82 [0.72-0.94]; P = .017) mortality with no statin-by-cholesterol interaction with respect to 30-day (adjusted Pint = 0.669) or 3-year (adjusted Pint = 0.767) all-cause mortality suggesting that statins reduce the risk of mortality irrespective of cholesterol level.

CONCLUSIONS

In patients with CAD, hypocholesterolaemia on admission was independently associated with increased risk of all-cause mortality at 30 days and 3 years after PCI.

The association between lipid profiles and the neurologic outcome in patients with out-of-hospital cardiac arrest

BACKGROUND

Lipid profiles are known to be a risk factor for development of cardiovascular disease. However, the relationship between lipid profiles and outcome in out-of-hospital cardiac arrest (OHCA) survivors remains unclear. We aimed to examine the association between lipid profiles and neurologic outcome in OHCA survivors.

METHODS

This retrospective observational study included adult (≥18 years) OHCA survivors between January 2016 and December 2018. We measured patients' lipid profiles after return of spontaneous circulation (ROSC) including total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglyceride. The primary outcome was neurologic outcome at hospital discharge. Good neurologic outcome was defined cerebral performance categories 1 and 2.

RESULTS

A total of 182 patients were included. Of them, 57 (31.3%) were discharged with good neurologic outcomes. Median serum levels of total cholesterol (178.0 vs. 123.0 mg/dL), HDL (44.0 vs. 31.0 mg/dL), and LDL (104.0 vs. 75.0 mg/dL) were significantly higher in patients with good neurologic outcome. The area under the curves of total cholesterol, HDL, LDL, and triglyceride were 0.742 (95% confidence interval [CI], 0.672-0.803), 0.729 (95% CI, 0.658-0.792), 0.683 (95% CI, 0.610-0.750), and 0.572 (95% CI, 0.497-0.645), respectively. Total cholesterol (odds ratio [OR], 1.013; 95% CI, 1.000-1.025; p = 0.043) and HDL (OR, 1.071; 95% CI, 1.021-1.123; p = 0.005) levels were associated with good neurologic outcomes.

CONCLUSIONS

The levels of total cholesterol and HDL after ROSC were associated with good neurologic outcomes in patients with OHCA, without considering the effect of other lipid profiles simultaneously.

Assessment of 7 trace elements in serum of patients with nontuberculous mycobacterial lung disease

Nontuberculous mycobacterial (NTM) lung diseases are an emerging cause of pulmonary infection, becoming more common in the clinical setting as incidence of NTM lung diseases steadily increases worldwide. Trace elements are essential micronutrients and are known to play many important roles in infectious diseases. We investigated the concentrations of trace elements in patients with NTM lung disease and compared these values to patients with pulmonary tuberculosis and healthy controls. A case-control study was conducted to evaluate the serum trace element concentrations in 95 patients with NTM lung disease, 97 patients with pulmonary tuberculosis, and 99 healthy control subjects. The serum concentrations of 7 trace elements (cobalt, copper, chromium, manganese, molybdenum, selenium, and zinc) were measured using inductively coupled plasma-mass spectrometry. We also analyzed demographic data, clinical outcomes, and other biochemical parameters. The median serum concentrations of copper and molybdenum were higher in patients with NTM lung disease (109 vs. 91 μg/dL, p < 0.001 and 1.70 vs. 0.96 μg/L, p < 0.001). In contrast, the median serum concentrations of selenium and zinc were significantly lower in patients with NTM lung disease than in healthy controls (105 vs. 115 μg/L, p < 0.001 and 94 vs. 102 μg/dL, p < 0.001). Compared to patients with pulmonary tuberculosis, the serum concentrations of molybdenum and zinc were higher in patients with NTM lung disease, while cobalt and copper concentrations were lower (p < 0.001). Correlations among trace element concentrations were observed (copper and zinc, r = -0.367; cobalt and molybdenum, r = -0.360; selenium and zinc, r = 0.335; and manganese and zinc, r = 0.327, respectively). None of the 7 trace elements were associated with treatment outcomes. Patients with NTM lung disease showed different serum trace element concentrations. Our study indicates that altered trace element status is associated with mycobacterial disease. Further study investigating the clinical significance of individual trace elements and their association with nutritional status in patients with NTM lung disease would be required.

Assessment of Vitamin Status in Patients with Nontuberculous Mycobacterial Pulmonary Disease: Potential Role of Vitamin A as a Risk Factor

As microbiological diagnostic techniques improve and the frequency of nontuberculous mycobacterial pulmonary disease (NTM-PD) infection increases worldwide, NTM-PD is becoming increasingly important to clinicians and researchers. Vitamin activity has been associated with the host immune response in tuberculosis; however, such information is very limited in NTM-PD. We performed a case-control study in 150 patients with NTM-PD and 150 healthy controls to investigate serum vitamin status. We measured concentrations of vitamins A, D, and E along with homocysteine and methylmalonic acid (MMA) as indicators of vitamin B₁₂ deficiency, using high-performance liquid chromatography (HPLC) or HPLC-tandem mass spectrometry. The serum concentrations of vitamins A and E were significantly lower in patients with NTM-PD than in healthy controls (1.5 vs. 2.1 µmol/L, p < 0.01 for vitamin A; and 27.3 vs. 33.1 µmol/L, p < 0.01 for vitamin E). In contrast, the serum concentrations of vitamin D and homocysteine were not significantly different between the two groups. Vitamin A deficiency (< 1.05 µmol/L) was significantly more prevalent in patients with NTM-PD than in healthy controls (p < 0.01) and was associated with an 11-fold increase in risk of NTM-PD. Multiple vitamin deficiencies were only observed in patients with NTM-PD (7.3% of all NTM-PD patients). Positive correlations were observed among vitamins (vitamins A and D; r = 0.200, p < 0.05; vitamins D and E, r = 0.238, p < 0.05; vitamins A and E, r = 0.352, p < 0.05). Serum vitamin status, demographic variables, and biochemical indicators were not associated with treatment outcomes. Vitamin A deficiency was strongly associated with patients with NTM-PD. Our study suggests that altered vitamin status is associated with mycobacterial disease. Future well-designed prospective studies with large patient cohorts addressing these issues are needed to clarify the significance of vitamins in NTM-PD.

Sheep and cattle exposed to Mycobacterium avium subspecies paratuberculosis exhibit altered total serum cholesterol profiles during the early stages of infection

Pathogenic mycobacteria such as Mycobacterium tuberculosis are capable of utilising cholesterol as a primary carbon-based energy source in vitro but there has been little research examining the significance of cholesterol in vivo. Johne's disease is a chronic enteric disease of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). This study sought to evaluate the levels of total serum cholesterol in the host following exposure to MAP. Blood samples were collected from both sheep and cattle prior to experimental challenge with MAP and at monthly intervals post-challenge. Total serum cholesterol levels in sheep challenged with MAP were significantly elevated at 9 weeks post-inoculation (wpi) in comparison to controls. When stratified based on disease outcome, there was no significant difference in serum cholesterol at the timepoints examined between MAP exposed sheep that were susceptible and those that were resistant to Johne's disease. There was a similar elevation in serum cholesterol at 9 wpi in cattle with histopathological gut lesions associated with disease or those with an early high IFN-γ response. Total serum cholesterol in exposed cattle was significantly lower when compared to controls at 13 wpi. Taken together, these results demonstrate changes in serum cholesterol following MAP exposure and disease progression which could reflect novel aspects of the pathogenesis and immune response associated with MAP infection in both sheep and cattle.

Severe persistent hypocholesterolemia after emergency gastrointestinal surgery predicts in-hospital mortality in critically ill patients with diffuse peritonitis

BACKGROUND

Plasma cholesterol acts as a negative acute phase reactant. Total cholesterol decreases after surgery and in various pathological conditions, including trauma, sepsis, burns, and liver dysfunction. This study aimed to determine whether hypocholesterolemia after emergency gastrointestinal (GI) surgery is associated with in-hospital mortality in patients with diffuse peritonitis.

METHODS

The medical records of 926 critically ill patients who had undergone emergency GI surgery for diffuse peritonitis, between January 2007 and December 2015, were retrospectively analyzed. The integrated areas under the curve (iAUCs) were calculated to compare the predictive accuracy of total cholesterol values from postoperative days (PODs) 0, 1, 3, and 7. Cox proportional hazard regression modeling was performed for all possible predictors identified in the univariate and multivariable analyses.

RESULTS

The total cholesterol level measured on POD 7 had the highest iAUC (0.7292; 95% confidence interval, 0.6696-0.7891) and was significantly better at predicting in-hospital mortality than measurements on other days. The optimal total cholesterol cut-off value for predicting in-hospital mortality was 61 mg/dL and was determined on POD 7. A Cox proportional hazard regression analysis revealed that a POD 7 total cholesterol level < 61 mg/dL was an independent predictor of in-hospital mortality after emergency GI surgery (hazard ratio, 3.961; 95% confidence interval, 1.786-8.784).

CONCLUSION

Severe persistent hypocholesterolemia (<61 mg/dL) on POD 7 independently predicted in-hospital mortality, after emergency GI surgery, in critically ill patients with diffuse peritonitis.

Lipid levels are inversely associated with infectious and all-cause mortality: international MONDO study results

Cardiovascular (CV) events are increased 36-fold in patients with end-stage renal disease. However, randomized controlled trials to lower LDL cholesterol (LDL-C) and serum total cholesterol (TC) have not shown significant mortality improvements. An inverse association of TC and LDL-C with all-cause and CV mortality has been observed in patients on chronic dialysis. Lipoproteins also may protect against infectious diseases. We used data from 37,250 patients in the international Monitoring Dialysis Outcomes (MONDO) database to evaluate the association between lipids and infection-related or CV mortality. The study began on the first day of lipid measurement and continued for up to 4 years. We applied Cox proportional models with time-varying covariates to study associations of LDL-C, HDL cholesterol (HDL-C), and triglycerides (TGs) with all-cause, CV, infectious, and other causes of death. Overall, 6,147 patients died (19.2% from CV, 13.2% from infection, and 67.6% from other causes). After multivariable adjustment, higher LDL-C, HDL-C, and TGs were independently associated with lower all-cause death risk. Neither LDL-C nor TGs were associated with CV death, and HDL-C was associated with lower CV risk. Higher LDL-C and HDL-C were associated with a lower risk of death from infection or other non-CV causes. LDL-C was associated with reduced all-cause and infectious, but not CV mortality, which resulted in the inverse association with all-cause mortality.

Changes in lipid metabolism in pediatric patients with severe sepsis and septic shock

OBJECTIVES

Limited knowledge exists regarding the lipid profiles of critically ill pediatric patients with systemic inflammatory response syndrome. The aim of this study was to evaluate the relationship between the intensity of the inflammatory response and changes in the lipid profiles of critically ill pediatric patients admitted to a pediatric intensive care unit (PICU) with severe sepsis/septic shock.

METHODS

This was a prospective and observational study at a 15-bed PICU at a public university hospital. We analyzed the lipid profiles of 40 patients with severe sepsis/septic shock admitted to the PICU on the first and seventh days of hospitalization. C-reactive protein was used as a marker for systemic inflammation. Forty-two pediatric patients seen in the emergency department and without systemic inflammatory response syndrome were used to provide control values.

RESULTS

On day 1 of admission to the PICU, the patients had significantly lower levels of total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) as well as higher concentrations of triacylglycerols compared with the control group. There was a significant increase in the TC, HDL, LDL, and apolipoprotein levels from day 1 to day 7 of the study.

CONCLUSIONS

During severe sepsis/septic shock, we found lower serum levels of lipoproteins and apolipoproteins, and these were negatively correlated with C-reactive protein. As the inflammatory response improved, the levels of TC, HDL, LDL, and apolipoproteins increased, suggesting a direct relationship between changes in the lipid profiles and inflammation.

Regulation of Ca2+-Sensitive K+ Channels by Cholesterol and Bile Acids via Distinct Channel Subunits and Sites

Cholesterol (CLR) conversion into bile acids (BAs) in the liver constitutes the major pathway for CLR elimination from the body. Moreover, these steroids regulate each other's metabolism. While the roles of CLR and BAs in regulating metabolism and tissue function are well known, research of the last two decades revealed the existence of specific protein receptors for CLR or BAs in tissues with minor contribution to lipid metabolism, raising the possibility that these lipids serve as signaling molecules throughout the body. Among other lipids, CLR and BAs regulate ionic current mediated by the activity of voltage- and Ca²⁺-gated, K⁺ channels of large conductance (BK channels) and, thus, modulate cell physiology and participate in tissue pathophysiology. Initial work attributed modification of BK channel function by CLR or BAs to the capability of these steroids to directly interact with bilayer lipids and thus alter the physicochemical properties of the bilayer with eventual modification of BK channel function. Based on our own work and that of others, we now review evidence that supports direct interactions between CLR or BA and specific BK protein subunits, and the consequence of such interactions on channel activity and organ function, with a particular emphasis on arterial smooth muscle. For each steroid type, we will also briefly discuss several mechanisms that may underlie modification of channel steady-state activity. Finally, we will present novel computational data that provide a chemical basis for differential recognition of CLR vs lithocholic acid by distinct BK channel subunits and recognition sites.

Dyslipdemia induced by chronic low dose co-exposure to lead, cadmium and manganese in rats: the role of oxidative stress

Lead (Pb), cadmium (Cd) and manganese (Mn) have many potential adverse health effects in vitro and in animal models of clinical toxicity. The current study investigated the dyslipidaemic and oxidative stress effects of chronic low-dose oral exposure to Pb, Cd and Mn and the combination (Pb+Cd+Mn) in rats for 15 weeks. Chronic exposure to the metals did not significantly (P>0.05) alter serum lipid profiles. However, the atherogenic index decreased by 32.2% in the Pb+Cd+Mn group, relative to the control. The triglyceride/high-density lipoprotein cholesterol ratio decreased by 39.4% in the Pb+Cd+Mn group, relative to the control, and elevated by 81.8, 94.8 and 20.8%, relative to the Pb, Cd and Mn groups, respectively. While the serum concentrations of malondialdehyde significantly increased in the Mn and Pb+Cd+Mn groups, that of glutathione peroxidase-1 decreased in the Pb+Cd+Mn group, and metallothionein-1 and zinc concentrations markedly decreased in all the metal treatment groups. The results suggest that long-term exposure of rats to Pb+Cd+Mn may result in hypolipidaemia, mediated via oxidative stress and metal interactions. Individuals who are constantly exposed to environmentally relevant levels of the metals may be at risk of hypolipidaemia.

Common structural features of cholesterol binding sites in crystallized soluble proteins

Cholesterol-protein interactions are essential for the architectural organization of cell membranes and for lipid metabolism. While cholesterol-sensing motifs in transmembrane proteins have been identified, little is known about cholesterol recognition by soluble proteins. We reviewed the structural characteristics of binding sites for cholesterol and cholesterol sulfate from crystallographic structures available in the Protein Data Bank. This analysis unveiled key features of cholesterol-binding sites that are present in either all or the majority of sites: i) the cholesterol molecule is generally positioned between protein domains that have an organized secondary structure; ii) the cholesterol hydroxyl/sulfo group is often partnered by Asn, Gln, and/or Tyr, while the hydrophobic part of cholesterol interacts with Leu, Ile, Val, and/or Phe; iii) cholesterol hydrogen-bonding partners are often found on α-helices, while amino acids that interact with cholesterol's hydrophobic core have a slight preference for β-strands and secondary structure-lacking protein areas; iv) the steroid's C21 and C26 constitute the "hot spots" most often seen for steroid-protein hydrophobic interactions; v) common "cold spots" are C8-C10, C13, and C17, at which contacts with the proteins were not detected. Several common features we identified for soluble protein-steroid interaction appear evolutionarily conserved.

Changes in cholesterol level correlate with the course of pulmonary nontuberculous mycobacterial disease

BACKGROUND

Nutritional assessment is important in patients with pulmonary nontuberculous mycobacterial (PNTM) disease. The therapeutic effect of a cholesterol-rich diet in tuberculosis (TB) patients has been demonstrated, but the role of cholesterol in PNTM disease is unclear. This study evaluated the sequential changes in nutritional markers, including cholesterol, total lymphocyte count and visceral fat volume, according to the PNTM disease course.

METHODS

This was an age-, sex- and number of comorbid diseases-matched case-control analysis of 89 patients with PNTM disease and 356 controls, who were participants in a Korean national survey.

RESULTS

The median body mass index (BMI) and cholesterol level in the PNTM group [BMI =19.7 kg/m²; interquartile range (IQR): 17.8-21.6; cholesterol: 159 mg/dL; IQR, 135-185] were lower than those in controls (BMI: 23.1 kg/m²; IQR, 21.3-25.3; cholesterol: 188 mg/dL; IQR, 164-217; both P<0.001). In a multivariate analysis, Age more than 70 years (OR =3.38; 95% CI: 1.13-10.15, P=0.029), BMI <19.5 kg/m² (OR =5.09; 95% CI: 1.67-15.48; P=0.004) and cavitary lesions (OR: 3.86; 95% CI: 1.30-11.47; P=0.015) were independently associated with extensive pulmonary lesions involving more than four lobes. The total cholesterol level, total lymphocyte count showed a tendency to decrease in PNTM patients with disease progression (both, P value <0.05), but not in those with a stable disease course. A decrease in cholesterol concentration of >20 mg/dL and a decrease in lymphocyte count more than 200/µL were predictive factors for disease progression (cholesterol: OR =10.50, 95% CI: 2.51-43.98, P=0.001; lymphocyte count: OR =5.32, 95% CI: 1.46-19.35, P=0.011).

CONCLUSIONS

These findings suggest that the change in cholesterol level may be a marker of disease progression in patients with PNTM disease.

On-Site Classification of Pansteatitis in Mozambique Tilapia (Oreochromis mossambicus) using a Portable Lipid-Based Analyzer

While no pansteatitis-related large-scale mortality events have occurred since 2008, the current status of pansteatitis (presence and pervasiveness) in the Olifants River system and other regions of South Africa remain largely unknown. In part, this is due to both a lack of known biological markers of pansteatitis and a lack of suitable non-invasive assays capable of rapidly classifying the disease. Here, we propose the application of a point-of-care (POC) device using lipid-based test strips (total cholesterol (TC) and total triglyceride (TG)), for classifying pansteatitis status in the whole blood of pre-spawning Mozambique tilapia (Oreochromis mossambicus). Using the TC strips, the POC device was able to non-lethally classify the tilapia as either healthy or pansteatitis-affected; the sexes were examined independently because sexual dimorphism was observed for TC (males p = 0.0364, females χ2 = 0.0007). No significant difference between diseased and pansteatitis-affected tilapia was observed using the TG strips. This is one of the first described applications of using POC devices for on-site environmental disease state testing. A discussion on the merits of using portable lipid-based analyzers as an in-field disease-state diagnostic tool is provided.

Malnutrition and Clinical Outcome of 234 Head and Neck Cancer Patients who Underwent Percutaneous Endoscopic Gastrostomy

Head and neck cancer (HNC) patients who underwent percutaneous endoscopic gastrostomy (PEG) present malnutrition risk and speech impairments. Their assessment relies on objective anthropometric/laboratory data. Focusing on HNC PEG patients, our aims were to evaluate: 1) outcome; 2) nutritional status when the patients underwent PEG; and 3) association of nutritional status/outcome, creating a survival predictive model. We evaluated the outcome based on NRS 2002, dietary assessment, body mass index (BMI), mid-upper arm circumference (MUAC), triceps skinfold thickness (TSF), mid-arm muscle circumference (MAMC), albumin, transferrin, and cholesterol on the day of gastrostomy. Using BMI, TSF, MAMC, and laboratory data, a survival predictive model was created. Of the 234 patients (cancer stages III-IV), 149 died, 33 were still PEG-fed, and 36 resumed oral intake (NRS-2002≥3, caloric needs <50% in all). BMI was 12.7-43. 189, 197, and 168 patients displayed, respectively, low MUAC, TSF, and MAMC. 91, 155, and 119 patients displayed low albumin, transferrin, and cholesterol. Albumin, cholesterol, and transferrin were strongly associated with the outcome. A predictive model was created, discriminating between short-term survivors (<4 months) and long-term survivors. HNC patients were malnourished. Using anthropometric/laboratory parameters, a predictive model provides discrimination between patients surviving PEG for <4 months and long-term survivors. Teams taking care of PEG patients may provide special support to potential short-term survivors.

Serum Lipoproteins Are Critical for Pulmonary Innate Defense against Staphylococcus aureus Quorum Sensing

Hyperlipidemia has been extensively studied in the context of atherosclerosis, whereas the potential health consequences of the opposite extreme, hypolipidemia, remain largely uninvestigated. Circulating lipoproteins are essential carriers of insoluble lipid molecules and are increasingly recognized as innate immune effectors. Importantly, severe hypolipidemia, which may occur with trauma or critical illness, is clinically associated with bacterial pneumonia. To test the hypothesis that circulating lipoproteins are essential for optimal host innate defense in the lung, we used lipoprotein-deficient mice and a mouse model of Staphylococcus aureus pneumonia in which invasive infection requires virulence factor expression controlled by the accessory gene regulator (agr) operon. Activation of agr and subsequent virulence factor expression is inhibited by apolipoprotein B, the structural protein of low-density lipoprotein, which binds and sequesters the secreted agr-signaling peptide (AIP). In this article, we report that lipoprotein deficiency impairs early pulmonary innate defense against S. aureus quorum-sensing-dependent pathogenesis. Specifically, apolipoprotein B levels in the lung early postinfection are significantly reduced with lipoprotein deficiency, coinciding with impaired host control of S. aureus agr-signaling and increased agr-dependent morbidity (weight loss) and inflammation. Given that lipoproteins also inhibit LTA- and LPS-mediated inflammation, these results suggest that hypolipidemia may broadly impact posttrauma pneumonia susceptibility to both Gram-positive and -negative pathogens. Together with previous reports demonstrating that hyperlipidemia also impairs lung innate defense, these results suggest that maintenance of normal serum lipoprotein levels is necessary for optimal host innate defense in the lung.

Apolipoprotein B48, the Structural Component of Chylomicrons, Is Sufficient to Antagonize Staphylococcus aureus Quorum-Sensing

Serum lipoproteins (LP) are increasingly being recognized as dual purpose molecules that contribute to both cholesterol homeostasis and host innate defense. In fact, very low LP levels are associated with increased risk of bacterial infection in critically ill patients. In this respect, we reported that apolipoprotein B100 (apoB100), the 4536 amino acid structural protein of very low density lipoprotein (VLDL) produced by the liver, limits Staphylococcus aureus pathogenesis. S. aureus uses quorum-sensing (QS) via the accessory gene regulator (agr) operon and an autoinducing peptide (AIP) to coordinate expression of over 200 virulence genes. ApoB100 prevents agr activation by binding and sequestering secreted AIP. Importantly, human serum LP are produced not only by the liver, but are also produced by enterocytes, in the form of chylomicrons, during uptake of dietary lipids. In contrast to apoB100 in VLDL, human enterocytes use apoB48, the N-terminal 2152 amino acids (48%) of apoB100, as the structural component of chylomicrons. Interestingly, enteral feeding of critically ill patients has been associated with decreased risk of infectious complications, suggesting chylomicrons could contribute to host innate defense in critically ill patients when serum LP production by the liver is limited during the acute phase response. Therefore, we hypothesized that apoB48 would be sufficient to antagonize S. aureus QS. As expected, isolated apoB48-LP bound immobilized AIP and antagonized agr-signaling. ApoB48- and apoB100-LP inhibited agr activation with IC50s of 3.5 and 2.3 nM, respectively, demonstrating a conserved AIP binding site. Importantly, apoB48-LP antagonized QS, limited morbidity and promoted bacterial clearance in a mouse model of S. aureus infection. This work demonstrates that both naturally occurring forms of apolipoprotein B can antagonize S. aureus QS, and may suggest a previously unrecognized role for chylomicrons and enterocytes in host innate defense against S. aureus QS-mediated pathogenesis.

Inflammatory bowel disease and risk of coronary heart disease

Emerging data have shown consistent evidence of an association between inflammation and development of atherosclerosis. Systemic autoimmune diseases are characterized by chronic inflammation and immune dysregulation, and diseases such as rheumatoid arthritis and lupus erythematosus are now commonly accepted to associate with development of cardiovascular disease, including coronary artery disease. However, the risk of cardiovascular disease in inflammatory bowel disease (IBD), a chronic inflammatory disease of the gut, is still unclear and the magnitude of a potentially increased risk is continuously debated. The aim of this review is to give an update on the existing literature on the association between inflammatory bowel disease and risk of cardiovascular disease, in particular coronary artery disease, and further to discuss traditional and non-traditional risk factors in patients with inflammatory bowel disease.

Critical illness is associated with decreased plasma levels of coenzyme Q10: a cross-sectional study

PURPOSE

Plasma coenzyme Q10 (CoQ10) levels are lower in patients with septic shock (SS) than in healthy controls (HCs). However, CoQ10 status in critically ill patients without SS is unknown. Here, we investigated CoQ10 concentrations in patients with SS and without SS as compared with HCs.

MATERIALS AND METHODS

We enrolled 36 critically ill patients and 18 HCs. Plasma CoQ10 concentrations were measured, and patients' clinical and demographical data were collected.

RESULTS

Plasma CoQ10 concentrations were lower in critically ill patients (0.50±0.36 μg/mL, P<.001), both in patients with SS (0.37±0.25 μg/mL, P=.002) and patients without SS (0.56±0.39, P=.04), as compared with HCs (0.79±0.19). Coenzyme Q10 levels did not differ between patients with SS and patients without SS (P=.13). In critically ill patients, CoQ10 levels inversely correlated with age (r=-0.40, P=.015) and did not correlate with partial pressure of oxygen in the arterial blood/fraction of inspired oxygen, Simplified Acute Physiology Score II, Systemic Organ Failure Assessment score, or mortality. Lower CoQ10 levels were associated with lower activities of daily living score after discharge (P=.005), independent of age.

CONCLUSIONS

Decreased plasma CoQ10 levels are not specific to patients with SS, but rather observed in a broad range of critically ill patients. In critically ill patients, CoQ10 insufficiency may be associated with various conditions; age may be a risk factor.

Characteristics of subjects with very low serum low-density lipoprotein cholesterol and the risk for intracerebral hemorrhage

BACKGROUND/AIMS

The clinical implications of hypocholesterolemia have not been well studied, although some studies have revealed an association between hypocholesterolemia and intracerebral hemorrhage (ICH). We evaluated the clinical characteristics of subjects with very low-density lipoprotein cholesterol (LDL-C) and compared the risk for ICH using various clinical parameters.

METHODS

Using hospital records, we evaluated the clinical characteristics of subjects with LDL-C levels ≤ 40 mg/dL (very low LDL-C group). We also evaluated the risk for ICH in this very low LDL-C group and in subjects with low LDL-C ≤ 70 mg/dL (low LDL-C group).

RESULTS

Among 34,415 subjects who presented at the laboratory for serum LDL-C measurements, 250 subjects had a very low serum LDL-C level (≤ 40 mg/dL). About half of the subjects were statin users; the very low LDL levels in the other subjects were likely attributable to alcohol consumption or a various chronic illness such as liver disease or end-stage renal disease (ESRD). ICH occurred in three subjects with very low LDL-C, all of whom had no history of statin use. ESRD tended to be associated with ICH in subjects with serum LDL-C ≤ 70 mg/dL.

CONCLUSIONS

About 1% of the subjects whose LDL-C was measured in the hospital had a LDL-C level ≤ 40 mg/dL, and about half of these subjects had no history of hypolipidemic therapy. ICH incidence was not related to LDL-C level or statin use.