Epigenetic susceptibility to severe respiratory viral infections and its therapeutic implications: a narrative review.

The emergence of highly pathogenic strains of influenza virus and coronavirus (CoV) has been responsible for large epidemic and pandemic outbreaks characterised by severe pulmonary illness associated with high morbidity and mortality. One major challenge for critical care is to stratify and minimise the risk of multi-organ failure during the stay in the intensive care unit (ICU). Epigenetic-sensitive mechanisms, including deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) methylation, histone modifications, and non-coding RNAs may lead to perturbations of the host immune-related transcriptional programmes by regulating chromatin structure and gene expression patterns. Viruses causing severe pulmonary illness can use epigenetic-regulated mechanisms during host-pathogen interaction to interfere with innate and adaptive immunity, adequacy of inflammatory response, and overall outcome of viral infections. For example, Middle East respiratory syndrome-CoV and H5N1 can affect host antigen presentation through DNA methylation and histone modifications. The same mechanisms would presumably occur in patients with coronavirus disease 2019, in which tocilizumab may epigenetically reduce microvascular damage. Targeting epigenetic pathways by immune modulators (e.g. tocilizumab) or repurposed drugs (e.g. statins) may provide novel therapeutic opportunities to control viral-host interaction during critical illness. In this review, we provide an update on epigenetic-sensitive mechanisms and repurposed drugs interfering with epigenetic pathways which may be clinically suitable for risk stratification and beneficial for treatment of patients affected by severe viral respiratory infections.

Epigenetics Mechanisms in Multiorgan Dysfunction Syndrome.

Epigenetic mechanisms including deoxyribonucleic acid (DNA) methylation, histone modifications (eg, histone acetylation), and microribonucleic acids (miRNAs) have gained much scientific interest in the last decade as regulators of genes expression and cellular function. Epigenetic control is involved in the modulation of inflammation and immunity, and its dysregulation can contribute to cell damage and organ dysfunction. There is growing evidence that epigenetic changes can contribute to the development of multiorgan dysfunction syndrome (MODS), a leading cause of mortality in the intensive care unit (ICU). DNA hypermethylation, histone deacetylation, and miRNA dysregulation can influence cytokine and immune cell expression and promote endothelial dysfunction, apoptosis, and end-organ injury, contributing to the development of MODS after a critical injury. Epigenetics processes, particularly miRNAs, are emerging as potential biomarkers of severity of disease, organ damage, and prognostic factors in critical illness. Targeting epigenetics modifications can represent a novel therapeutic approach in critical care. Inhibitors of histone deacetylases (HDCAIs) with anti-inflammatory and antiapoptotic activities represent the first class of drugs that reverse epigenetics modifications with human application. Further studies are required to acquire a complete knowledge of epigenetics processes, full understanding of their individual variability, to expand their use as accurate and reliable biomarkers and as safe target to prevent or attenuate MODS in critical disease.

The Effect of Modified Ultrafiltration on Serum Vancomycin Levels During Cardiopulmonary Bypass in Cardiac Surgery.

OBJECTIVE: The aim of this study was to investigate whether the use of modified ultrafiltration at the end of cardiopulmonary bypass for cardiac surgical procedures significantly changes vancomycin serum concentrations. DESIGN: Prospective study. SETTING: Single tertiary cardiac center. PARTICIPANTS: Twenty-six elective adult patients undergoing cardiac surgery with cardiopulmonary bypass from April 2014 to April 2015. INTERVENTIONS: Serum vancomycin concentrations were measured just before cardiopulmonary bypass; during cardiopulmonary bypass at 5, 30, 60 minutes and then every 60 minutes; after completion of cardiopulmonary bypass before initiation of modified ultrafiltration; and at the end of modified ultrafiltration. MEASUREMENTS AND MAIN RESULTS: Seventeen patients received modified ultrafiltration at the end of cardiopulmonary bypass. Serum vancomycin concentrations prior to cardiopulmonary bypass (45.9 ± 17.3 µg/mL) were significantly higher (P < 0.0001) than each time point following cardiopulmonary bypass (5 min 20.4 ± 6.4 µg/mL, 30 min 18.8 ± 5.4 µg/mL, 60 min 16.6 ± 4.9 µg/mL, and 120 min 14.3 ± 4.7 µg/mL). In the modified ultrafiltration group, serum vancomycin concentrations were 14.7 ± 4.6 µg/mL prior to modified ultrafiltration and 13.9 ± 4.3 µg/mL after ultrafiltration; this difference was statistically significant (P  =  0.0288). The mean modified ultrafiltration volume was 465 ± 158 mL. CONCLUSIONS: Using modified ultrafiltration at the end of cardiopulmonary bypass significantly decreases serum vancomycin levels, but not by a clinically relevant amount. The decrease is to a concentration that is still significantly higher than the minimum inhibitory concentration for Staphylococcus epidermidis and Staphylococcus aureus; thus additional vancomycin administration is not recommended.

Nutrition and metabolic support for critically ill patients.

PURPOSE OF REVIEW: Acute critical illness increases the risk of malnutrition, are more obese, and have multiple comorbidities and frequent pre-existing nutritional deficits. There is a vast amount of research and literature being written on nutritional practices in the critically ill. We review and discuss herein the important nutrition literature over the past 12 months. RECENT FINDINGS: Sarcopenia, defined as loss of skeletal mass and strength, is associated with increased mortality and morbidity, particularly in elderly patients with trauma. Ultrasound is emerging as a noninvasive and promising method of measuring muscularity. Measuring gastric residuals and postpyloric feeding may not decrease rates of pneumonia in critically ill patients. Trophic and full feeding lead to similar long-term functional and cognitive outcomes in patients with acute respiratory distress syndrome. SUMMARY: Nutrition and metabolic support of critically ill patients is a complex and diverse topic. Nutritional measurements, requirements, and modes and routes of delivery are currently being studied to determine the best way to treat these complicated patients. We present just a few of the current controversial topics in this fascinating arena.

Improved Technical Skill and Procedure Time With Central Venous Catheter Simulation.

Simulation manikins provide anesthetists a training modality to practice ultrasound-guided central venous catheter (CVC) insertion safely without the risk of patient harm. The goals of this quality improvement (QI) project were to increase technical skills and reduce procedure time among anesthesia providers during CVC placement by implementing an ultrasoundguided, simulated CVC insertion workshop. A primary benefit of simulation-based education is the provision of a safe learning environment-one in which learners and providers may practice and increase skillsets. This QI project utilized a pretest-posttest design for which anesthesia providers completed a CVC insertion educational session and three formally evaluated simulated CVC placements: preworkshop, immediate postworkshop, and 3 months postworkshop. CVC insertion skills were evaluated by two experienced raters who established interrater reliability using a validated checklist and recorded procedure time in minutes. When comparing preworkshop median checklist score (33.74/52 [65%]), significant improvement was found in the immediate postworkshop (46.32/52 [89%]) and 3-month follow-up (44.26/52 [85%]). Time for CVC insertion significantly improved immediately postworkshop (15.7 minutes) and 3-month follow-up (15.9 minutes) when compared with preworkshop (21.5 minutes). An ultrasound-guided CVC simulation workshop can appreciably advance anesthesia providers' technical skills and decrease procedure time when performing insertion of a simulated internal jugular CVC.

Practice Patterns of Transesophageal Echocardiography Use Among Trauma Patients: A Multi-Institutional Retrospective Study.

Transesophageal echocardiography (TEE) can be utilized for hemodynamic monitoring and resuscitation. In order to study the pattern of TEE use in trauma patients, a multi-institutional retrospective cohort study was performed comparing adult trauma patients who underwent TEE or those who underwent traditional invasive hemodynamic monitoring (TIHM). TIHM was defined as the use of arterial line, central venous line, or pulmonary artery catheter without TEE. Mortality rates were obtained and multivariable logistic regression was used to risk adjust for age, gender, race, insurance status, Glasgow coma scale (GCS), ICD Injury severity score (ICISS). Compared to TIHM group, more patients in TEE group had a history of congestive heart failure (CHF) or chronic pulmonary disease (CPD). Mortality rate was lower in the TEE group 7 versus 23% (P-value < .0001). After adjusting for GCS and ICISS in multivariable analysis, inpatient mortality was significantly lower in the TEE cohort.

Optimal timing and outcomes among COVID-19 patients undergoing tracheostomy.

BACKGROUND: Patients who require mechanical ventilation secondary to severe COVID-19 infection have poor survival. It is unknown if the benefit of tracheostomy extends to COVID-19 patients. If so, what is the optimal timing? METHODS: Retrospective cohort study within a large hospital system in the United States. The population included patients with COVID-19 from January 1, 2020 to September 30, 2020. In total, 93,918 cases were identified. They were excluded if no intubation or tracheostomy, underwent tracheostomy before intubation, <18 years old, hospice patients before admission, and bacterial pneumonia. In total, 5,911 patients met the criteria. Outcomes between patients who underwent endotracheal intubation only versus tracheostomy were compared. The primary outcome was inpatient mortality. All patients who underwent tracheostomy versus intubation only were compared. Three cohort analysis compared early (<10 days) versus late (>10 days) tracheostomy versus control. Eight cohort analysis compared days 0-2, days 3-6, days 7-10, days 11-14, days 15-18, days 19-22, and days 23+ to tracheostomy versus control. RESULTS: There was an overall inpatient mortality rate of 37.5% in the tracheostomy cohort compared to 54.4% in the control group (P < .0001). There was an early tracheostomy group inpatient mortality rate of 44.7% (adjusted odds ratio 0.73, 95% confidence interval 0.52-1.01) compared to 33.1% (adjusted odds ratio 0.44, 95% confidence interval 0.34-0.58) in the late tracheostomy group. CONCLUSION: COVID-19 patients with tracheostomy had a significantly lower mortality rate compared to intubated only. Optimal timing for tracheostomy placement for COVID-19 patients is 11 days or later. Future studies should focus on early tracheostomy patients.

Beneficial effects of prehospital use of statins in a large United States cohort of hospitalized coronavirus disease 2019 patients.

AIMS: This large cohort study aimed to assess the role of chronic statin use on COVID-19 disease severity. METHODS: An observational retrospective study from electronic medical records of hospitalized patients (n = 43 950) with COVID-19 between January and September 2020 in 185 hospitals in the United States. A total of 38 875 patients met inclusion criteria; 23 066 were included in the propensity-matched sampling with replacement cohort; 11 533 were prehospital statin users. The primary outcome was all-cause death; secondary outcomes were death from COVID-19 and serious complications. Mean, standard deviation, chi-square test, Student's t-test, linear regression, and binary and multinomial logistic regressions were used for statistical analysis. RESULTS: Among 38 875 patients, 30% were chronic statin users [mean age, 70.82 (±12.25); 47.1% women] and 70% were statin nonusers [mean age, 58.44 (±18.27); 48.5% women]. Key propensity-matched outcomes among 11 533 chronic statin users showed 20% lower risk of all-cause mortality (OR 0.80, 95% CI 0.74-0.86, P < 0.001), 23% lower risk of mortality from COVID-19 (OR 0.77, 95% CI 0.71-0.84, P < 0.001), 16% lower risk of ICU admission (OR 0.84, 95% CI 0.79-0.89, P < 0.001), 24% lower risk of critical acute respiratory distress syndrome with COVID-19 (OR 0.76, 95% CI 0.70-0.83, P < 0.001), 23% lower risk of mechanical ventilation (OR 0.77, 95% CI 0.71-0.82, P < 0.001), 20% lower risk of severe sepsis with septic shock (OR 0.80, 95% CI 0.67-0.93, P = 0.004), shorter hospital length of stay [9.87 (±8.94), P < 0.001] and brief duration of mechanical ventilation [8.90 (±8.94), P < 0.001]. CONCLUSION: Chronic use of statins is associated with reduced mortality and improved clinical outcomes in patients hospitalized for COVID-19.

Transesophageal echocardiography guidance for stent-graft repair of a thoracic aneurysm is facilitated by the ability of partial stent deployment.

Transesophageal echocardiography (TEE) is routinely used in our Institution for monitoring correct positioning of thoracic aortic stent grafts. We present a case of successful endovascular repair of three discrete thoracic aortic aneurysms with Zenith TX2 endovascular stent grafts in an 82-year-old female patient. Our focus is on the increased value of TEE guidance because of the ability of partial stent deployment and manipulation during insertion.

Administration of hydrogen sulfide via extracorporeal membrane lung ventilation in sheep with partial cardiopulmonary bypass perfusion: a proof of concept study on metabolic and vasomotor effects.

INTRODUCTION: Although inhalation of 80 parts per million (ppm) of hydrogen sulfide (H2S) reduces metabolism in mice, doses higher than 200 ppm of H2S were required to depress metabolism in rats. We therefore hypothesized that higher concentrations of H2S are required to reduce metabolism in larger mammals and humans. To avoid the potential pulmonary toxicity of H2S inhalation at high concentrations, we investigated whether administering H2S via ventilation of an extracorporeal membrane lung (ECML) would provide means to manipulate the metabolic rate in sheep. METHODS: A partial venoarterial cardiopulmonary bypass was established in anesthetized, ventilated (fraction of inspired oxygen = 0.5) sheep. The ECML was alternately ventilated with air or air containing 100, 200, or 300 ppm H2S for intervals of 1 hour. Metabolic rate was estimated on the basis of total CO2 production (VCO2) and O2 consumption (VO2). Continuous hemodynamic monitoring was performed via indwelling femoral and pulmonary artery catheters. RESULTS: VCO2, VO2, and cardiac output ranged within normal physiological limits when the ECML was ventilated with air and did not change after administration of up to 300 ppm H2S. Administration of 100, 200 and 300 ppm H2S increased pulmonary vascular resistance by 46, 52 and 141 dyn·s/cm5, respectively (all P ≤ 0.05 for air vs. 100, 200 and 300 ppm H2S, respectively), and mean pulmonary artery pressure by 4 mmHg (P ≤ 0.05), 3 mmHg (n.s.) and 11 mmHg (P ≤ 0.05), respectively, without changing pulmonary capillary wedge pressure or cardiac output. Exposure to 300 ppm H2S decreased systemic vascular resistance from 1,561 ± 553 to 870 ± 138 dyn·s/cm(5) (P ≤ 0.05) and mean arterial pressure from 121 ± 15 mmHg to 66 ± 11 mmHg (P ≤ 0.05). In addition, exposure to 300 ppm H2S impaired arterial oxygenation (PaO2 114 ± 36 mmHg with air vs. 83 ± 23 mmHg with H2S; P ≤ 0.05). CONCLUSIONS: Administration of up to 300 ppm H2S via ventilation of an extracorporeal membrane lung does not reduce VCO2 and VO2, but causes dose-dependent pulmonary vasoconstriction and systemic vasodilation. These results suggest that administration of high concentrations of H2S in venoarterial cardiopulmonary bypass circulation does not reduce metabolism in anesthetized sheep but confers systemic and pulmonary vasomotor effects.

Cerebrospinal fluid findings and hypernatremia in COVID-19 patients with altered mental status.

BACKGROUND: The objective of the study was to assess the cerebrospinal fluid (CSF) findings in COVID-19 patients. AIMS: This was an observational retrospective cohort from electronic medical records of hospitalized patients (n = 2655) with confirmed COVID-19 between February 15, 2020, and April 15, 2020, in 182 hospitals from a large health system in the USA. The review of data yielded to a total of 79 patients in 20 hospitals who had CSF analysis. METHODS: Outcomes during hospitalization, including hospital length of stay, disease severity, ventilator time, and in-hospital death were recorded. Independent variables collected included patient demographics, diagnoses, laboratory values, and procedures. RESULTS: A total of 79 patients underwent CSF analysis. Of these, antigen testing was performed in 73 patients. Ten patients had CSF analysis for general markers such as total protein, cell count, glucose, clarity, and color. Seven of the 10 cases (70%) had normal total cell count and normal white blood cell count in CSF. Sixty-three percent (5/8) had elevated total protein. Two patients had normal levels of lactate dehydrogenase (LDH) and 1 patient had significantly elevated (fourfold) neuron-specific enolase (NSE) level in CSF. CONCLUSION: Unlike bacterial infections, viral infections are less likely to cause remarkable changes in CSF glucose, cell count, or protein. Our observations showed no pleocytosis, but mild increase in protein in the CSF of the COVID-19 patients. The fourfold elevation of NSE may have diagnostic/prognostic value as a biomarker in CSF for COVID-19 patients who have altered mental status.

Clinical epigenetics and multidrug-resistant bacterial infections: host remodelling in critical illness.

The inappropriate use of antibiotics in man is driving to insurgence of pathogenic bacteria resistant to multiple drugs (MDR) representing a challenge in critical illness. The interaction of MDR bacteria with host cells can guide molecular perturbations of host transcriptional programmes involving epigenetic-sensitive mechanisms, mainly DNA methylation, histone modifications, and non-coding RNAs leading to pathogen survival. Clinical evidence of epigenetic manipulation from MDR bacteria mainly arises from Mycobacterium tuberculosis as well as Helicobacter pylori, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Legionella pneumophila infection suggesting possible biomarkers of disease. For example, DNA hypermethylation of E-cadherin (CDH1), upstream transcription factor 1/2 (USF1/2), WW domain containing oxidoreductase (WWOX), and mutL homolog 1 (MLH1) genes in gastric mucosa is correlated with malignancy suggesting useful biomarkers of early disease state. Moreover, upregulated circulating miR-361-5p, miR-889, miR-576-3p may be useful biomarkers to discriminate tuberculosis patients. Moreover, Listeria monocytogenes can indirectly induce H3 hyperacetylation leading to inflammation in human endothelial cells whereas Pseudomonas aeruginosa excretes QS 2-AA to directly induce H3 deacetylation leading to bacterial persistence in human monocytes. Remarkably, epigenetic-sensitive drugs may aid to counteract MDR in clinical setting. Trichostatin A, a histone deacetyltransferase inhibitor (HDACi), leads to AMP ß-defensin 2 (HBD2) gene up-regulation in human epithelial cells suggesting a useful 'epi-therapy' for Escherichia coli-induced intestinal diseases. We update on the most current clinical studies focusing on epigenetic changes involved in bacterial-host interactions and their putative role as biomarkers or drug targets to improve precision medicine and personalized therapy in critical illness and transplantation setting.

Long-term treatment with sulfhydryl angiotensin-converting enzyme inhibition reduces carotid intima-media thickening and improves the nitric oxide/oxidative stress pathways in newly diagnosed patients with mild to moderate primary hypertension.

BACKGROUND: Sulfhydryl angiotensin-converting enzyme (ACE) inhibitors exert antiatherosclerotic effects in preclinical models and antioxidant effects in patients. However, whether ACE inhibitors have any clinically significant antiatherogenic effects remains still debated. OBJECTIVES: In mildly hypertensive patients, we evaluated the effect of the sulfhydryl ACE inhibitor zofenopril in comparison with the carboxylic ACE inhibitor enalapril on carotid atherosclerosis (intima-media thickness [IMT] and vascular lumen diameter) and systemic oxidative stress (nitrite/nitrate, asymmetrical dimethyl-l-arginine, and isoprostanes). METHODS: In 2001, we started a small prospective randomized clinical trial on 48 newly diagnosed mildly hypertensive patients with no additional risk factors for atherosclerosis (eg, hyperlipidemia, smoke habit, familiar history of atherosclerosis-related diseases or diabetes). Patients were randomly assigned either to the enalapril (20 mg/d, n = 24) or the zofenopril group (30 mg/d, n = 24); the planned duration of the trial was 5 years. Carotid IMT and vascular lumen diameter were determined by ultrasonography for all patients at baseline and at 1, 3, and 5 years. Furthermore, nitrite/nitrate, asymmetrical dimethyl-l-arginine, and isoprostane levels were measured. RESULTS: In our conditions, IMT of the right and left common carotid arteries was similar at baseline in both groups (P = NS). Intima-media thickness measurements until 5 years revealed a significant reduction in the zofenopril group but not in the enalapril group (P < .05 vs enalapril-treated group). This effect was coupled with a favorable nitric oxide/oxidative stress profile in the zofenopril group. CONCLUSIONS: Long-term treatment with the sulfhydryl ACE inhibitor zofenopril besides its blood pressure-lowering effects may slow the progression of IMT of the carotid artery in newly diagnosed mildly hypertensive patients.

Differential gene profiling in acute lung injury identifies injury-specific gene expression.

OBJECTIVES: Acute lung injury can result from distinct insults, such as sepsis, ischemia-reperfusion, and ventilator-induced lung injury. Physiologic and morphologic manifestations of disparate forms of injury are often indistinguishable. We sought to demonstrate that acute lung injury resulting from distinct insults may lead to different gene expression profiles. DESIGN: Microarray analysis was used to examine early molecular events in lungs from three rat models of acute lung injury: lipopolysaccharide, hemorrhage shock/resuscitation, and high-volume ventilation. SETTING: University laboratory. SUBJECTS: Male Sprague-Dawley rats (body weight, 300-350 g). INTERVENTIONS: Rats were subjected to hemorrhagic shock or lipopolysaccharide followed by resuscitation or were subjected to sham operation. First hit was followed by ventilation with either low (6 mL/kg) or high (12 mL/kg) tidal volume for 4 hrs. MEASUREMENTS AND MAIN RESULTS: Physiologic and morphologic variables were assessed. Total RNA was hybridized to Affymetrix chips. Bioconductor was used to identify significantly altered genes. Functional enrichment predictions were performed in Gene Ontology Tree Machine. Confirmation studies included real-time polymerase chain reaction, Western blots, and immunohistochemistry. Physiologic and morphologic variables were noncontributory in determining the cause of acute lung injury. In contrast, molecular analysis revealed unique gene expression patterns that characterized exposure to lipopolysaccharide and high-volume ventilation. We used hypergeometric probability to demonstrate that specific functional enrichment groups were regulated by biochemical vs. biophysical factors. Genes stimulated by lipopolysaccharide were involved in metabolism, defense response, immune cell proliferation, differentiation and migration, and cell death. In contrast, high-volume ventilation led to the regulation of genes involved primarily in organogenesis, morphogenesis, cell cycle, proliferation, and differentiation. CONCLUSIONS: These results demonstrate the application of functional genomics to the molecular "fingerprinting" of acute lung injury and the potential for decoupling biophysical from biochemical injury.

Therapeutic dose of nebivolol, a nitric oxide-releasing beta-blocker, reduces atherosclerosis in cholesterol-fed rabbits.

Nitric oxide (NO) exerts a plethora of vascular beneficial effects. The NO-releasing beta-blocker nebivolol is a racemic mixture of D/L-enantiomers that displays negative inotropic as well as direct vasodilating activity. The in vivo antiatherogenic activity of therapeutic doses of the beta-blocker with antioxidant properties carvedilol (12.5mg/day) or nebivolol (5mg/day) was tested in cholesterol-fed rabbits. Animals received a 1% cholesterol-rich diet alone (controls) or mixed with drugs (treated animals) for 8 weeks. While it did not affect hyperlipidemia, nebivolol inhibited the development of atherosclerosis, expressed as computer-assisted imaging analysis of aortic area covered by lesions (23.3+/-4.1% in treated vs 38.2+/-6.4% in control animals, p<0.01). Differently, in our experimental condition of therapeutic drug doses, this antiatherogenic effect did not reach statistical significance in rabbits treated with carvedilol (32.5+/-5.1% aortic area covered by lesions, p=NS vs controls). Plasma nitrates increased in rabbits treated with nebivolol while both beta-blockers reduced LDL oxidation. Moreover, nebivolol induced a consistent increase of endothelial reactivity and aortic eNOS expression compared with control animals (p<0.05) and those receiving carvedilol (p<0.05). Since NO may exert beneficial effects in atherosclerosis, a NO-dependent mechanism could explain this data. These observations suggest that the NO-releasing beta-blocker, nebivolol, might represent an effective pharmacological approach for preventing atherosclerotic lesion progression.

Functional impairment of hematopoietic progenitor cells in patients with coronary heart disease.

The circulating form of endothelial progenitors cells (EPCs) are derived from bone marrow (BM)-derived hematopoietic stem cells (HSCs). Enhanced mobilization of EPCs was shown to be linked to cardiac diseases. This study investigated whether reduced EPC levels in advanced coronary heart disease (CHD) are secondary to a functional exhaustion of HSCs in the BM or to reduced mobilization. Number and functional properties of EPCs were assessed in 15 healthy controls, and 40 patients with CHD. The colony-forming unit (CFU) capacity of BM-derived mononuclear cells and the CD34+ HSC number were examined in four healthy volunteers, and 15 CHD patients. EPC number was reduced in CHD patients (P < 0.01 vs. controls). Moreover, the migratory capacity was significantly impaired in EPCs of CHD patients (P < 0.05 vs. controls). On multivariate analysis, CHD was an independent predictor of functional EPC impairment. CFUs were reduced in CHD patients (59.6 +/- 21.2 vs. 75.4 +/- 25.8 in controls, P < 0.05). CHD was also predictor of impaired CFU capacity. In this small clinical study, CHD is associated with selective impairment of HSC function in the BM and in the peripheral blood, which may contribute to impairment of cardiac function.

The role of oxidative stress in adult critical care.

Oxidative stress defines an imbalance in production of oxidizing chemical species and their effective removal by protective antioxidants and scavenger enzymes. Evidence of massive oxidative stress is well established in adult critical illnesses characterized by tissue ischemia-reperfusion injury and by an intense systemic inflammatory response such as during sepsis and acute respiratory distress syndrome. Oxidative stress could exacerbate organ injury and thus overall clinical outcome. We searched MEDLINE databases (January 1966 to June 2005). For interventional studies, we accepted only randomized trials. Several small clinical trials have been performed in order to reduce oxidative stress by supplementation of antioxidants alone or in combination with standard therapies. These studies have reported controversial results. Newer large multicenter trials with antioxidant supplementation should be performed, considering administration at an early stage of illness and a wider population of critically ill patients.

Role of oxidative stress in experimental sepsis and multisystem organ dysfunction.

Massive increase in radical species can lead to oxidative stress, promoting cell injury and death. This review focuses on experimental evidence of oxidative stress in critical illnesses, sepsis and multisystem organ dysfunction. Oxidative stress could negatively affect organ injury and thus overall survival of experimental models. Based on this experimental evidence, we could improve the rationale of supplementation of antioxidants alone or in combination with standard therapies aimed to reduce oxidative stress as novel adjunct treatment in critical care.

Severe Type 2 Diabetes Induces Reversible Modifications of Endothelial Progenitor Cells Which are Ameliorate by Glycemic Control.

BACKGROUND: Circulating endothelial progenitors cells (EPCs) play a critical role in neovascularization and endothelial repair. There is a growing evidence that hyperglycemia related to Diabetes Mellitus (DM) decreases EPC number and function so promoting vascular complications. AIM OF THE STUDY: This study investigated whether an intensive glycemic control regimen in Type 2 DM can increase the number of EPCs and restores their function. METHODS: Sixty-two patients with Type 2 DM were studied. Patients were tested at baseline and after 3 months of an intensive regimen of glycemic control. The Type 2 DM group was compared to control group of subjects without diabetes. Patients with Type 2 DM (mean age 58.2±5.4 years, 25.6% women, disease duration of 15.4±6.3 years) had a baseline HgA1c of 8.7±0.5% and lower EPC levels (CD34+/KDR+) in comparison to healthy controls (p<0.01). RESULTS: The intensive glycemic control regimen (HgA1c decreased to 6.2±0.3%) was coupled with a significant increase of EPC levels (mean of 18%, p<0.04 vs. baseline) and number of EPCs CFUs (p<0.05 vs. baseline). CONCLUSION: This study confirms that number and bioactivity of EPCs are reduced in patients with Type 2 DM and, most importantly, that the intensive glycemic control in Type 2 DM promotes EPC improvement both in their number and in bioactivity.