Sepsis and the Obesity Paradox: Size Matters in More Than One Way.

OBJECTIVES: Multiple studies have demonstrated an obesity paradox such that obese ICU patients have lower mortality and better outcomes. We conducted this study to determine if the mortality benefit conferred by obesity is affected by baseline serum lactate and mean arterial pressure. DESIGN: Retrospective analysis of prospectively collected clinical data. SETTING: Five community-based and one academic medical center in the Omaha, NE. PATIENTS: 7,967 adults hospitalized with sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were categorized by body mass index as underweight, normal weight, overweight, or obese. Multivariable logistic regression models were used to estimate the odds of in-hospital death by body mass index category; two-way interactions between body mass index and each covariate were also evaluated. Subgroup and sensitivity analyses were conducted using an ICU cohort and Acute Physiology and Chronic Health Evaluation III scores, respectively. The overall unadjusted mortality rate was 12.1% and was consistently lower in higher body mass index categories (all comparisons, p < 0.007). The adjusted mortality benefit observed in patients with higher body mass index was smaller in patients with higher lactate levels with no mortality benefit in higher body mass index categories observed at lactate greater than 5 mmol/L. By contrast, the association between lower MAP and higher mortality was constant across body mass index categories. Similar results were observed in the ICU cohort. Finally, the obesity paradox was not observed after including Acute Physiology and Chronic Health Evaluation III scores as a covariate. CONCLUSIONS: Our retrospective analysis suggests that although patient size (i.e., body mass index) is a predictor of in-hospital death among all-comers with sepsis-providing further evidence to the obesity paradox-it adds that illness severity is critically important whether quantified as higher lactate or by Acute Physiology and Chronic Health Evaluation III score. Our results highlight that the obesity paradox is more than a simple association between body mass index and mortality and reinforces the importance of illness severity.

Adenoviral gene transfer corrects the ion transport defect in the sinus epithelia of a porcine CF model.

Cystic fibrosis (CF) pigs spontaneously develop sinus and lung disease resembling human CF. The CF pig presents a unique opportunity to use gene transfer to test hypotheses to further understand the pathogenesis of CF sinus disease. In this study, we investigated the ion transport defect in the CF sinus and found that CF porcine sinus epithelia lack cyclic AMP (cAMP)-stimulated anion transport. We asked whether we could restore CF transmembrane conductance regulator gene (CFTR) current in the porcine CF sinus epithelia by gene transfer. We quantified CFTR transduction using an adenovirus expressing CFTR and green fluorescent protein (GFP). We found that as little as 7% of transduced cells restored 6% of CFTR current with 17-28% of transduced cells increasing CFTR current to 50% of non-CF levels. We also found that we could overcorrect cAMP-mediated current in non-CF epithelia. Our findings indicate that CF porcine sinus epithelia lack anion transport, and a relatively small number of cells expressing CFTR are required to rescue the ion transport phenotype. These studies support the use of the CF pig as a preclinical model for future gene therapy trials in CF sinusitis.

The POSITIONED Study: Prone Positioning in Nonventilated Coronavirus Disease 2019 Patients-A Retrospective Analysis.

Given perceived similarities between coronavirus disease 2019 pneumonia and the acute respiratory distress syndrome, we explored whether awake self-proning improved outcomes in coronavirus disease 2019-infected patients treated in a rural medical center with limited resources during a significant local coronavirus disease 2019 outbreak. DESIGN: Retrospective analysis of prospectively collected clinical data. SETTING: Single-center rural community-based medical center in Grand Island, NE. PATIENTS: One hundred five nonintubated, coronavirus disease-infected patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: After patients were educated on the benefits of awake self-proning, compliance was voluntary. The primary outcome was need for intubation during the hospital stay; secondary outcomes included serial peripheral capillary oxygen saturation measured by pulse oximetry to the Fio2 ratios, in-hospital mortality, and discharge disposition. Of 105 nonintubated, coronavirus disease-infected patients, 40 tolerated awake self-proning. Patients who were able to prone were younger and had lower disease severity. The risk of intubation was lower in proned patients after adjusting for disease severity using Sequential Organ Failure Assessment scores (adjusted hazard ratio, 0.30; 95% CI, 0.09-0.96; p = 0.043) or Acute Physiology and Chronic Health Evaluation II scores (adjusted hazard ratio, 0.30; 95% CI, 0.10-0.91; p = 0.034). No prone patient died compared with 24.6% of patients who were not prone (p < 0.001; number needed to treat = 5; 95% CI, 3-8). The probability of being discharged alive and peripheral capillary oxygen saturation measured by pulse oximetry to the Fio2 ratios were statistically similar for both groups. CONCLUSIONS: Awake self-proning was associated with lower mortality and intubation rates in coronavirus disease 2019-infected patients. Prone positioning appears to be a safe and inexpensive strategy to improve outcomes and spare limited resources. Prospective efforts are needed to better delineate the effect of awake proning on oxygenation and to improve patients' ability to tolerate this intervention.

The effect of geniglossal advancement on airway flow using a computational flow dynamics model.

OBJECTIVES/HYPOTHESIS: Obstructive sleep apnea (OSA) is a sleep disorder caused by partial or complete collapse of the pharyngeal airway. Genioglossal advancement (GGA) is a well-tolerated surgical procedure intended to address hypopharyngeal collapse, yet there are few studies that monitor changes in airflow dynamics at this site. Computation fluid dynamics (CFD) utilizes airflow simulation to predict changes in airflow after anatomic manipulation. STUDY DESIGN: We investigated the change in volume and airflow dynamics of the pharyngeal airway after GGA in a cadaveric model. METHODS: We performed serial GGA from 1 mm (control) to 3, 7, and 9 mm on a lightly preserved cadaver. After each intervention, we performed high-resolution computed tomography scans, reconstructed the pharyngeal airway, and quantified airspace volume and CFD analysis with both laminar and large eddy simulation models. RESULTS: Airway volume increased with linear GGA. In both CFD simulation models, velocity increased and pressure decreased after 9-mm advancement secondary to increased airway diameter and less abrupt changes in airway geometry. CONCLUSIONS: These results suggest that GGA may be effective in increasing airway volume and flow to address hypopharyngeal obstruction in OSA.

Intestinal CFTR expression alleviates meconium ileus in cystic fibrosis pigs.

Cystic fibrosis (CF) pigs develop disease with features remarkably similar to those in people with CF, including exocrine pancreatic destruction, focal biliary cirrhosis, micro-gallbladder, vas deferens loss, airway disease, and meconium ileus. Whereas meconium ileus occurs in 15% of babies with CF, the penetrance is 100% in newborn CF pigs. We hypothesized that transgenic expression of porcine CF transmembrane conductance regulator (pCFTR) cDNA under control of the intestinal fatty acid-binding protein (iFABP) promoter would alleviate the meconium ileus. We produced 5 CFTR-/-;TgFABP>pCFTR lines. In 3 lines, intestinal expression of CFTR at least partially restored CFTR-mediated anion transport and improved the intestinal phenotype. In contrast, these pigs still had pancreatic destruction, liver disease, and reduced weight gain, and within weeks of birth, they developed sinus and lung disease, the severity of which varied over time. These data indicate that expressing CFTR in intestine without pancreatic or hepatic correction is sufficient to rescue meconium ileus. Comparing CFTR expression in different lines revealed that approximately 20% of wild-type CFTR mRNA largely prevented meconium ileus. This model may be of value for understanding CF pathophysiology and testing new preventions and therapies.

Lentiviral vector gene transfer to porcine airways.

In this study, we investigated lentiviral vector development and transduction efficiencies in well-differentiated primary cultures of pig airway epithelia (PAE) and wild-type pigs in vivo. We noted gene transfer efficiencies similar to that observed for human airway epithelia (HAE). Interestingly, feline immunodeficiency virus (FIV)-based vectors transduced immortalized pig cells as well as pig primary cells more efficiently than HIV-1-based vectors. PAE express TRIM5α, a well-characterized species-specific lentiviral restriction factor. We contrasted the restrictive properties of porcine TRIM5α against FIV- and HIV-based vectors using gain and loss of function approaches. We observed no effect on HIV-1 or FIV conferred transgene expression in response to porcine TRIM5α overexpression or knockdown. To evaluate the ability of GP64-FIV to transduce porcine airways in vivo, we delivered vector expressing mCherry to the tracheal lobe of the lung and the ethmoid sinus of 4-week-old pigs. One week later, epithelial cells expressing mCherry were readily detected. Our findings indicate that pseudotyped FIV vectors confer similar tropisms in porcine epithelia as observed in human HAE and provide further support for the selection of GP64 as an appropriate envelope pseudotype for future preclinical gene therapy studies in the porcine model of cystic fibrosis (CF).Molecular Therapy - Nucleic Acids (2012) 1, e56; doi:10.1038/mtna.2012.47; published online 27 November 2012.

Sinus hypoplasia precedes sinus infection in a porcine model of cystic fibrosis.

OBJECTIVES/HYPOTHESIS: Chronic sinusitis is nearly universal in humans with cystic fibrosis (CF) and is accompanied by sinus hypoplasia (small sinuses). However, whether impaired sinus development is a primary feature of loss of the cystic fibrosis transmembrane conductance regulator (CFTR) or a secondary consequence of chronic infection remains unknown. Our objective was to study the early pathogenesis of sinus disease in CF. STUDY DESIGN: Animal/basic science research. METHODS: Sinus development was studied in a porcine CF model. RESULTS: Porcine sinus epithelia expressed CFTR and exhibited transepithelial anion transport. Disruption of the CFTR gene eliminated both. Sinuses of newborn CF pigs were not infected and showed no evidence of inflammation, yet were hypoplastic at birth. Older CF pigs spontaneously developed sinus disease similar to that seen in humans with CF. CONCLUSIONS: These results define a role for CFTR in sinus development and suggest the potential of the CF pig as a genetic model of CF-sinus disease in which to test therapeutic strategies to minimize sinus-related CF morbidity.