Small Bowel Obstruction Caused by Bezoar Formation Around Intraluminal Hernia Mesh

We present a case report wherein a 55-year-old female presented to our clinic with chronic nausea, vomiting, and dehydration in the setting of a complex past surgical history, including laparoscopic incisional hernia repair in 2007 with intraperitoneal TiMesh^TM. She then developed chronic nausea and vomiting and was hospitalized numerous times for dehydration. Due to her ongoing symptoms, she was taken to the operating room for exploration. A large, firm, mobile mass was identified within a loop of small bowel and was found to be a large bezoar firmly attached to a piece of intraluminal mesh. She progressed well postoperatively and, on outpatient follow-up, her pre-operative abdominal symptoms had completely resolved. To our knowledge, this is the first reported case of gallstone-like bezoar formation around an intraluminal hernia mesh causing small bowel obstruction and chronic abdominal pain.

Effect of Hernia Mesh Weights on Postoperative Patient-Related and Clinical Outcomes After Open Ventral Hernia Repair: A Randomized Clinical Trial

Importance

Although multiple versions of polypropylene mesh devices are currently available on the market for hernia repair, few comparisons exist to guide surgeons as to which device may be preferable for certain indications. Mesh density is believed to impact patient outcomes, including rates of chronic pain and perception of mesh in the abdominal wall.

Objective

To examine whether medium-weight polypropylene is associated with less pain at 1 year compared with heavy-weight mesh.

Design, Setting, and Participants

This multicenter randomized clinical trial was performed from March 14, 2017, to April 17, 2019, with 1-year follow-up. Patients undergoing clean, open ventral hernia repairs with a width 20 cm or less were studied. Patients were blinded to the intervention.

Interventions

Patients were randomized to receive medium-weight or heavy-weight polypropylene mesh during open ventral hernia repair.

Main Outcomes and Measures

The primary outcome was pain measured with the National Institutes of Health (NIH) Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity Short Form 3a. Secondary outcomes included quality of life and pain measured at 30 days, quality of life measured at 1 year, 30-day postoperative morbidity, and 1-year hernia recurrence.

Results

A total of 350 patients participated in the study, with 173 randomized to receive heavy-weight polypropylene mesh (84 [48.6%] female; mean [SD] age, 59.2 [11.4] years) and 177 randomized to receive medium-weight polypropylene mesh (91 [51.4%] female; mean [SD] age, 59.3 [11.4] years). No significant differences were found in demographic characteristics (mean [SD] body mass index of 32.0 [5.4] in both groups [calculated as weight in kilograms divided by height in meters squared] and American Society of Anesthesiologists classes of 2-4 in both groups), comorbidities (122 [70.5%] vs 93 [52.5%] with hypertension, 44 [25.4%] vs 43 [24.3%] with diabetes, 17 [9.8%] vs 12 [6.8%] with chronic obstructive pulmonary disease), or operative characteristics (modified hernia grade of 2 in 130 [75.1] vs 140 [79.1] in the heavy-weight vs medium-weight mesh groups). Pain scores for patients in the heavy-weight vs medium-weight mesh groups at 30 days (46.3 vs 46.3, P = .89) and 1 year (30.7 vs 30.7, P = .59) were identical. No significant differences in quality of life (median [interquartile range] hernia-specific quality of life score at 1 year of 90.0 [67.9-96.7] vs 86.7 [65.0-93.3]; median [interquartile range] hernia-specific quality of life score at 30 days, 45.0 [24.6-73.8] vs 43.3 [28.3-65.0]) were found for the heavy-weight mesh vs medium-weight mesh groups. Composite 1-year recurrence rates for patients in the heavy-weight vs medium-weight polypropylene groups were similar (8% vs 7%, P = .79).

Conclusions and Relevance

Medium-weight polypropylene did not demonstrate any patient-perceived or clinical benefit over heavy-weight polypropylene after open retromuscular ventral hernia repair. Long-term follow-up of these comparable groups will elucidate any potential differences in durability that have yet to be identified.

Trial Registration

ClinicalTrials.gov Identifier: NCT03082391.

Selective Imaging of Lung Macrophages Using [11C]PBR28-Based Positron Emission Tomography

PURPOSE

We tested whether the translocator protein (TSPO)-targeted positron emission tomography (PET) tracer, N-acetyl-N-(2-[¹¹C]methoxybenzyl)-2-phenoxy-5-pyridinamine ([¹¹C]PBR28), could distinguish macrophage dominant from neutrophilic inflammation better than 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) in mouse models of lung inflammation and assessed TSPO association with macrophages in lung tissue from the mouse models and in patients with chronic obstructive pulmonary disease (COPD).

PROCEDURES

MicroPET imaging quantified [¹¹C]PBR28 and [¹⁸F]FDG lung uptake in wild-type (Wt) C57BL/6J or heterozygous transgenic monocyte-deficient Wt/opT mice at 49 days after Sendai virus (SeV) infection, during macrophage-dominant inflammation, and in Wt mice at 3 days after SeV infection or 24 h after endotoxin instillation during neutrophilic inflammation. Immunohistochemical staining for TSPO in macrophages and neutrophils was performed using Mac3 and Ly6G for cell identification in mouse lung sections and CD68 and neutrophil elastase (NE) in human lung sections taken from explanted lungs from patients with COPD undergoing lung transplantation and donor lungs rejected for transplantation. Differences in tracer uptake among SeV-infected, endotoxin-treated, and uninfected/untreated control mice and in TSPO staining between neutrophils and macrophage populations in human lung sections were tested using analysis of variance.

RESULTS

In Wt mice, [¹¹C]PBR28 uptake (% injected dose/ml lung tissue) increased significantly with macrophage-dominant inflammation at 49 days (D49) after SeV infection compared to controls (p = <0.001) but not at 3 days (D49) after SeV infection (p = 0.167). [¹¹C]PBR28 uptake was unchanged at 24 h after endotoxin instillation (p = 0.958). [¹⁸F]FDG uptake increased to a similar degree in D3 and D49 SeV-infected and endotoxin-treated Wt mice compared to controls with no significant difference in the degree of increase among the tested conditions. [¹¹C]PBR28 but not [¹⁸F]FDG lung uptake at D49 post-SeV infection was attenuated in Wt/opT mice compared to Wt mice. TSPO localized predominantly to macrophages in mouse lung tissue by immunostaining, and TSPO staining intensity was significantly higher in CD68+ cells compared to neutrophils in the human lung sections.

CONCLUSIONS

PET imaging with [¹¹C]PBR28 can specifically detect macrophages versus neutrophils during lung inflammation and may be a useful biomarker of macrophage accumulation in lung disease.

Prospective, multicenter study of P4HB (Phasix™) mesh for hernia repair in cohort at risk for complications: 3-Year follow-up

BACKGROUND

This study represents a prospective, multicenter, open-label study to assess the safety, performance, and outcomes of poly-4-hydroxybutyrate (P4HB, Phasix™) mesh for primary ventral, primary incisional, or multiply-recurrent hernia in subjects at risk for complications. This study reports 3-year clinical outcomes.

MATERIALS AND METHODS

P4HB mesh was implanted in 121 patients via retrorectus or onlay technique. Physical exam and/or quality of life surveys were completed at 1, 3, 6,12, 18, 24, and 36 months, with 5-year (60-month) follow-up ongoing.

RESULTS

A total of n = 121 patients were implanted with P4HB mesh (n = 75 (62%) female) with a mean age of 54.7 ± 12.0 years and mean BMI of 32.2 ± 4.5 kg/m2 (±standard deviation). Comorbidities included: obesity (78.5%), active smokers (23.1%), COPD (28.1%), diabetes mellitus (33.1%), immunosuppression (8.3%), coronary artery disease (21.5%), chronic corticosteroid use (5.0%), hypo-albuminemia (2.5%), advanced age (5.0%), and renal insufficiency (0.8%). Hernias were repaired via retrorectus (n = 45, 37.2% with myofascial release (MR) or n = 43, 35.5% without MR), onlay (n = 8, 6.6% with MR or n = 24, 19.8% without MR), or not reported (n = 1, 0.8%). 82 patients (67.8%) completed 36-month follow-up. 17 patients (17.9% ± 0.4%) experienced hernia recurrence at 3 years, with n = 9 in the retrorectus group and n = 8 in the onlay group. SSI (n = 11) occurred in 9.3% ± 0.03% of patients.

CONCLUSIONS

Long-term outcomes following ventral hernia repair with P4HB mesh demonstrate low recurrence rates at 3-year (36-month) postoperative time frame with no patients developing late mesh complications or requiring mesh removal. 5-year (60-month) follow-up is ongoing.

Evaluation of Wound Photography for Remote Postoperative Assessment of Surgical Site Infections

Importance

Surgeons are increasingly interested in using mobile and online applications with wound photography to monitor patients after surgery. Early work using remote care to diagnose surgical site infections (SSIs) demonstrated improved diagnostic accuracy using wound photographs to augment patients' electronic reports of symptoms, but it is unclear whether these findings are reproducible in real-world practice.

Objective

To determine how wound photography affects surgeons' abilities to diagnose SSIs in a pragmatic setting.

Design, Setting, and Participants

This prospective study compared surgeons' paired assessments of postabdominal surgery case vignettes with vs without wound photography for detection of SSIs. Data for case vignettes were collected prospectively from May 1, 2007, to January 31, 2009, at Erasmus University Medical Center, Rotterdam, the Netherlands, and from July 1, 2015, to February 29, 2016, at Vanderbilt University Medical Center, Nashville, Tennessee. The surgeons were members of the American Medical Association whose self-designated specialty is general, abdominal, colorectal, oncologic, or vascular surgery and who completed internet-based assessments from May 21 to June 10, 2016.

Intervention

Surgeons reviewed online clinical vignettes with or without wound photography.

Main Outcomes and Measures

Surgeons' diagnostic accuracy, sensitivity, specificity, confidence, and proposed management with respect to SSIs.

Results

A total of 523 surgeons (113 women and 410 men; mean [SD] age, 53 [10] years) completed a mean of 2.9 clinical vignettes. For the diagnosis of SSIs, the addition of wound photography did not change accuracy (863 of 1512 [57.1%] without and 878 of 1512 [58.1%] with photographs). Photographs decreased sensitivity (from 0.58 to 0.50) but increased specificity (from 0.56 to 0.63). In 415 of 1512 cases (27.4%), the addition of wound photography changed the surgeons' assessment (215 of 1512 [14.2%] changed from incorrect to correct and 200 of 1512 [13.2%] changed from correct to incorrect). Surgeons reported greater confidence when vignettes included a wound photograph compared with vignettes without a wound photograph, regardless of whether they correctly identified an SSI (median, 8 [interquartile range, 6-9] vs median, 8 [interquartile range, 7-9]; P < .001) but they were more likely to undertriage patients when vignettes included a wound photograph, regardless of whether they correctly identified an SSI.

Conclusions and Relevance

In a practical simulation, wound photography increased specificity and surgeon confidence, but worsened sensitivity for detection of SSIs. Remote evaluation of patient-generated wound photographs may not accurately reflect the clinical state of surgical incisions. Effective widespread implementation of remote postoperative assessment with photography may require additional development of tools, participant training, and mechanisms to verify image quality.

Ataxin-7 and Non-stop coordinate SCAR protein levels, subcellular localization, and actin cytoskeleton organization

Atxn7, a subunit of SAGA chromatin remodeling complex, is subject to polyglutamine expansion at the amino terminus, causing spinocerebellar ataxia type 7 (SCA7), a progressive retinal and neurodegenerative disease. Within SAGA, the Atxn7 amino terminus anchors Non-stop, a deubiquitinase, to the complex. To understand the scope of Atxn7-dependent regulation of Non-stop, substrates of the deubiquitinase were sought. This revealed Non-stop, dissociated from Atxn7, interacts with Arp2/3 and WAVE regulatory complexes (WRC), which control actin cytoskeleton assembly. There, Non-stop countered polyubiquitination and proteasomal degradation of WRC subunit SCAR. Dependent on conserved WRC interacting receptor sequences (WIRS), Non-stop augmentation increased protein levels, and directed subcellular localization, of SCAR, decreasing cell area and number of protrusions. In vivo, heterozygous mutation of SCAR did not significantly rescue knockdown of Atxn7, but heterozygous mutation of Atxn7 rescued haploinsufficiency of SCAR.

Triggering Receptor Expressed on Myeloid Cells-2 Expression Tracks With M2-Like Macrophage Activity and Disease Severity in COPD

BACKGROUND

Cell and animal models show a key role for Triggering Receptor Expressed on Myeloid Cells (TREM)-2 in chronic airway disease after viral infection, but comparable evidence in humans still needs to be established.

METHODS

Lung tissue samples were obtained from lung transplant recipients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage IV COPD (n = 16), nontransplantable donor lung tissues (n = 7), and resected lung tissues from patients at risk or with GOLD stage I through IV (n = 55) and were assessed for TREM-2 and TREM-1 messenger RNA (mRNA), protein expression, and other markers of a type 2 immune response.

RESULTS

TREM2 (but not TREM1) mRNA levels were increased in GOLD stage IV COPD lung tissues compared with non-COPD lung tissues. TREM2 mRNA was coexpressed with its signaling molecule DAP12 and the macrophage marker CD68 and M2-macrophage markers CD206 and CHIT1. TREM-2 protein was also increased in COPD lung tissues and was localized to CD14+ macrophages by flow cytometry and CD68+ and CCR2+ macrophages by tissue immunostaining. In lung samples from patients at risk and with GOLD stage I through IV COPD, TREM2 but not TREM1 mRNA levels were also increased, and the ratio of TREM2/TREM1 mRNA levels was associated with increases in CHIT1 mRNA and decreases in FEV1 and FEV1/FVC.

CONCLUSIONS

TREM-2 expression is increased in lung macrophages in COPD, particularly in comparison with TREM-1. Therefore, TREM-2 levels and the ratio of TREM-2/TREM-1 signifies M2 activation in COPD lung tissues and may help to guide therapeutics directed against the type 2 immune response in patients with this disease.

Frequency of endoscopic surveillance for Barrett's esophagus is influenced by health insurance status: results from a population-based analysis

Factors that influence the frequency of surveillance endoscopy for nondysplastic Barrett's esophagus are not well understood. The objective of this study is to assess factors which influence the frequency of endoscopic surveillance for Barrett's esophagus, including health insurance/third-party payer status. Cases of nondysplastic Barrett's esophagus undergoing esophagogastroduodenoscopy with biopsy were identified using longitudinal data from the Healthcare Utilization Project database in 2005-2006 and followed through 2011. The threshold for appropriate surveillance utilization was defined as two to four surveillance esophagogastroduodenoscopies over a standardized 5-year period. Patients' insurance status was designated as either Medicare, Medicaid, private, or noninsured. 36,676 cases of nondysplastic Barrett's esophagus were identified. Among these, 4,632 patients (12.6%) underwent between two and four surveillance esophagogastroduodenoscopies in 5 years of follow-up versus 31,975 patients (87.3%) who underwent fewer than two esophagogastroduodenoscopies during follow-up. Multivariate analysis found that Barrett's patients insured through Medicaid (OR 1.273; 95% CI = 1.065-1.522) or without insurance (OR = 2.453; 95% CI = 1.67-3.603) were at increased likelihood of being under-surveilled. This study identified a difference in frequency of surveillance esophagogastroduodenoscopy for Barrett's esophagus by payer status. Patients without health insurance and those whose primary insurance was Medicaid were at increased odds for under-surveillance. These data suggest that a more robust system for tracking and ensuring longitudinal follow-up of patients with Barrett's esophagus, with attention to the uninsured and underinsured population, may be needed to ensure optimal surveillance.

Heller myotomy versus Heller myotomy with Dor fundoplication for achalasia: long-term symptomatic follow-up of a prospective randomized controlled trial

BACKGROUND

Our prior randomized controlled trial of Heller myotomy alone versus Heller plus Dor fundoplication for achalasia from 2000 to 2004 demonstrated comparable postoperative resolution of dysphagia but less gastroesophageal reflux after Heller plus Dor. Patient-reported outcomes are needed to determine whether the findings are sustained long-term.

METHODS

We actively engaged participants from the prior randomized cohort, making up to six contact attempts per person using telephone, mail, and electronic messaging. We collected patient-reported measures of dysphagia and gastroesophageal reflux using the Dysphagia Score and the Gastroesophageal Reflux Disease-Health-Related Quality of Life (GERD-HRQL) instrument. Patient-reported re-interventions for dysphagia were verified by obtaining longitudinal medical records.

RESULTS

Among living participants, 27/41 (66%) were contacted and all completed the follow-up study at a mean of 11.8 years postoperatively. Median Dysphagia Scores and GERD-HRQL scores were slightly worse for Heller than Heller plus Dor but were not statistically different (6 vs 3, p = 0.08 for dysphagia, 15 vs 13, p = 0.25 for reflux). Five patients in the Heller group and 6 in Heller plus Dor underwent re-intervention for dysphagia with most occurring more than five years postoperatively. One patient in each group underwent redo Heller myotomy and subsequent esophagectomy. Nearly all patients (96%) would undergo operation again.

CONCLUSIONS

Long-term patient-reported outcomes after Heller alone and Heller plus Dor for achalasia are comparable, providing support for either procedure.

Identifying Futile Interfacility Surgical Transfers

Surgeons perceive that some surgical transfers are futile, but the incidence and risk factors of futile transfer are not quantified. Identifying futile interfacility transfers could save cost and undue burdens to patients and families. We sought to describe the incidence and factors associated with futile transfers. We conducted a retrospective cohort study from 2009 to 2013 including patients transferred to a tertiary referral center for general or vascular surgical care. Futile transfers were defined as resulting in death or hospice discharge within 72 hours of transfer without operative, endoscopic, or radiologic intervention. One per cent of patient transfers were futile (27/1696). Characteristics of futile transfers included older age, higher comorbidity burden and illness severity, vascular surgery admission, Medicare insurance, and surgeon documentation of end-stage disease as a factor in initial decision-making. Among futile transfers, 82 per cent were designated as do not resuscitate (vs 9% of nonfutile, P < 0.01), and 59 per cent received a palliative care consult (vs 7%, P < 0.01). A small but salient proportion of transferred patients undergo deliberate care de-escalation and early death or hospice discharge without intervention. Efforts to identify such patients before transfer through improved communication between referring and accepting surgeons may mitigate burdens of transfer and facilitate more comfortable deaths in patients' local communities.

Identifying Futile Interfacility Surgical Transfers

Surgeons perceive that some surgical transfers are futile, but the incidence and risk factors of futile transfer are not quantified. Identifying futile interfacility transfers could save cost and undue burdens to patients and families. We sought to describe the incidence and factors associated with futile transfers. We conducted a retrospective cohort study from 2009 to 2013 including patients transferred to a tertiary referral center for general or vascular surgical care. Futile transfers were defined as resulting in death or hospice discharge within 72 hours of transfer without operative, endoscopic, or radiologic intervention. One per cent of patient transfers were futile (27/ 1696). Characteristics of futile transfers included older age, higher comorbidity burden and illness severity, vascular surgery admission, Medicare insurance, and surgeon documentation of end-stage disease as a factor in initial decision-making. Among futile transfers, 82 per cent were designated as do not resuscitate (vs 9% of nonfutile, P < 0.01), and 59 per cent received a palliative care consult (vs 7%, P < 0.01). A small but salient proportion of transferred patients undergo deliberate care de-escalation and early death or hospice discharge without intervention. Efforts to identify such patients before transfer through improved communication between referring and accepting surgeons may mitigate burdens of transfer and facilitate more comfortable deaths in patients’ local communities.

Unnecessary Transfers for Acute Surgical Care: Who and Why?

Interhospital transfers for acute surgical care occur commonly, but without clear guidelines or protocols. Transfers may subject patients and delivery systems to significant burdens without clear clinical benefit. The incidence and factors associated with unnecessary transfers are not well described. We conducted a retrospective cohort study of patient transfers within a regional referral network to a tertiary center for nontrauma acute surgical care from 2009 to 2013. Clinically unnecessary transfers were defined as transfers that resulted in no intervention (operation, endoscopy, or interventional radiology procedure) and discharge to home within 72 hours. We performed bivariate and multivariate logistic regression analyses. The study population included 2177 patient transfers, 19 per cent of which were determined to be clinically unnecessary. After adjustment, clinically unnecessary transfers were more commonly performed for patient request (odds ratio = 2.52, 95% confidence interval = 1.60-3.99), continuity of care (1.87, 1.44-2.42), and care by urologic (1.50, 1.06-2.13) and vascular services (1.44, 1.03-2.01). Patients with higher comorbidity and severity of illness scores were less likely to have unnecessary transfers. The burden of unnecessary transfers could be mitigated by identifying appropriate transfer candidates through mutually developed guidelines, interfacility collaboration, and increased use of remote care to provide surgical subspecialty consultation and maintain continuity.

Unnecessary Transfers for Acute Surgical Care: Who and Why?

Interhospital transfers for acute surgical care occur commonly, but without clear guidelines or protocols. Transfers may subject patients and delivery systems to significant burdens without clear clinical benefit. The incidence and factors associated with unnecessary transfers are not well described. We conducted a retrospective cohort study of patient transfers within a regional referral network to a tertiary center for nontrauma acute surgical care from 2009 to 2013. Clinically unnecessary transfers were defined as transfers that resulted in no intervention (operation, endoscopy, or interventional radiology procedure) and discharge to home within 72 hours. We performed bivariate and multivariate logistic regression analyses. The study population included 2177 patient transfers, 19 per cent of which were determined to be clinically unnecessary. After adjustment, clinically unnecessary transfers were more commonly performed for patient request (odds ratio = 2.52, 95% confidence interval = 1.60–3.99), continuity of care (1.87, 1.44–2.42), and care by urologic (1.50, 1.06–2.13) and vascular services (1.44, 1.03–2.01). Patients with higher comorbidity and severity of illness scores were less likely to have unnecessary transfers. The burden of unnecessary transfers could be mitigated by identifying appropriate transfer candidates through mutually developed guidelines, interfacility collaboration, and increased use of remote care to provide surgical subspecialty consultation and maintain continuity.

Myb permits multilineage airway epithelial cell differentiation

The epithelium of the pulmonary airway is specially differentiated to provide defense against environmental insults, but also subject to dysregulated differentiation that results in lung disease. The current paradigm for airway epithelial differentiation is a one-step program whereby a p63(+) basal epithelial progenitor cell generates a ciliated or secretory cell lineage, but the cue for this transition and whether there are intermediate steps are poorly defined. Here, we identify transcription factor Myb as a key regulator that permits early multilineage differentiation of airway epithelial cells. Myb(+) cells were identified as p63(-) and therefore distinct from basal progenitor cells, but were still negative for markers of differentiation. Myb RNAi treatment of primary-culture airway epithelial cells and Myb gene deletion in mice resulted in a p63(-) population with failed maturation of Foxj1(+) ciliated cells as well as Scbg1a1(+) and Muc5ac(+) secretory cells. Consistent with these findings, analysis of whole genome expression of Myb-deficient cells identified Myb-dependent programs for ciliated and secretory cell differentiation. Myb(+) cells were rare in human airways but were increased in regions of ciliated cells and mucous cell hyperplasia in samples from subjects with chronic obstructive pulmonary disease. Together, the results show that a p63(-) Myb(+) population of airway epithelial cells represents a distinct intermediate stage of differentiation that is required under normal conditions and may be heightened in airway disease.

Postoperative Care Using a Secure Online Patient Portal: Changing the (Inter)Face of General Surgery

BACKGROUND

Many patients seek greater accessibility to health care. Meanwhile, surgeons face increasing time constraints due to workforce shortages and elevated performance demands. Online postoperative care may improve patient access while increasing surgeon efficiency. We aimed to evaluate patient and surgeon acceptance of online postoperative care after elective general surgical operations.

STUDY DESIGN

A prospective pilot study within an academic general surgery service compared online and in-person postoperative visits from May to December 2014. Included patients underwent elective laparoscopic cholecystectomy, laparoscopic ventral hernia repair, umbilical hernia repair, or inguinal hernia repair by 1 of 5 surgeons. Patients submitted symptom surveys and wound pictures, then corresponded with their surgeons using an online patient portal. The primary outcome was patient-reported acceptance of online visits in lieu of in-person visits. Secondary outcomes included detection of complications via online visits, surgeon-reported effectiveness, and visit times.

RESULTS

Fifty patients completed both online and in-person visits. Online visits were acceptable to most patients as their only follow-up (76%). For 68% of patients, surgeons reported that both visit types were equally effective, while clinic visits were more effective in 24% and online visits in 8%. No complications were missed via online visits, which took significantly less time for patients (15 vs 103 minutes, p < 0.01) and surgeons (5 vs 10 minutes, p < 0.01).

CONCLUSIONS

In this population, online postoperative visits were accepted by patients and surgeons, took less time, and effectively identified patients who required further care. Further evaluation is needed to establish the safety and potential benefit of online postoperative visits in specific populations.

Imaging pulmonary inducible nitric oxide synthase expression with PET

Inducible nitric oxide synthase (iNOS) activity increases in acute and chronic inflammatory lung diseases. Imaging iNOS expression may be useful as an inflammation biomarker for monitoring lung disease activity. We developed a novel tracer for PET that binds to iNOS in vivo, (18)F-NOS. In this study, we tested whether (18)F-NOS could quantify iNOS expression from endotoxin-induced lung inflammation in healthy volunteers.

METHODS

Healthy volunteers were screened to exclude cardiopulmonary disease. Qualifying volunteers underwent a baseline, 1-h dynamic (18)F-NOS PET/CT scan. Endotoxin (4 ng/kg) was then instilled bronchoscopically in the right middle lobe. (18)F-NOS imaging was performed again approximately 16 h after endotoxin instillation. Radiolabeled metabolites were determined from blood samples. Cells recovered by bronchoalveolar lavage (BAL) after imaging were stained immunohistochemically for iNOS. (18)F-NOS uptake was quantified as the distribution volume ratio (DVR) determined by Logan plot graphical analysis in volumes of interest placed over the area of endotoxin instillation and in an equivalent lung region on the left. The mean Hounsfield units (HUs) were also computed using the same volumes of interest to measure density changes.

RESULTS

Seven healthy volunteers with normal pulmonary function completed the study with evaluable data. The DVR increased by approximately 30%, from a baseline mean of 0.42 ± 0.07 to 0.54 ± 0.12, and the mean HUs by 11% after endotoxin in 6 volunteers who had positive iNOS staining in BAL cells. The DVR did not change in the left lung after endotoxin. In 1 volunteer with low-level iNOS staining in BAL cells, the mean HUs increased by 7% without an increase in DVR. Metabolism was rapid, with approximately 50% of the parent compound at 5 min and 17% at 60 min after injection.

CONCLUSION

(18)F-NOS can be used to image iNOS activity in acute lung inflammation in humans and may be a useful PET tracer for imaging iNOS expression in inflammatory lung disease.

Evaluation of (89)Zr-pertuzumab in Breast cancer xenografts

Pertuzumab is a monoclonal antibody that binds to HER2 and is used in combination with another HER2–specific monoclonal antibody, trastuzumab, for the treatment of HER2+ metastatic breast cancer. Pertuzumab binds to an HER2 binding site distinct from that of trastuzumab, and its affinity is enhanced when trastuzumab is present. We aim to exploit this enhanced affinity of pertuzumab for its HER2 binding epitope and adapt this antibody as a PET imaging agent by radiolabeling with ⁸⁹Zr to increase the sensitivity of HER2 detection in vivo. Here, we investigate the biodistribution of ⁸⁹Zr-pertuzumab in HER2–expressing BT-474 and HER2–nonexpressing MDA-MB-231 xenografts to quantitatively assess HER2 expression in vivo. In vitro cell binding studies were performed resulting in retained immunoreactivity and specificity for HER2–expressing cells. In vivo evaluation of ⁸⁹Zr-pertuzumab was conducted in severely combined immunodeficient mice, subcutaneously inoculated with BT-474 and MDA-MB-231 cells. ⁸⁹Zr-pertuzumab was systemically administered and imaged at 7 days postinjection (p.i.) followed by terminal biodistribution studies. Higher tumor uptake was observed in BT-474 compared to MDA-MB-231 xenografts with 47.5 ± 32.9 and 9.5 ± 1.7% ID/g, respectively at 7 days p.i (P = 0.0009) and blocking studies with excess unlabeled pertuzumab showed a 5-fold decrease in BT-474 tumor uptake (P = 0.0006), confirming the in vivo specificity of this radiotracer. Importantly, we observed that the tumor accumulation of ⁸⁹Zr-pertuzumab was increased in the presence of unlabeled trastuzumab, at 173 ± 74.5% ID/g (P = 0.01). Biodistribution studies correlate with PET imaging quantification using max SUV (r = 0.98, P = 0.01). Collectively, these results illustrate that ⁸⁹Zr-pertuzumab as a PET imaging agent may be beneficial for the quantitative and noninvasive assessment of HER2 expression in vivo especially for patients undergoing trastuzumab therapy.

Increased iron sequestration in alveolar macrophages in chronic obstructive pulmonary disease

Free iron in lung can cause the generation of reactive oxygen species, an important factor in chronic obstructive pulmonary disease (COPD) pathogenesis. Iron accumulation has been implicated in oxidative stress in other diseases, such as Alzheimer’s and Parkinson’s diseases, but little is known about iron accumulation in COPD. We sought to determine if iron content and the expression of iron transport and/or storage genes in lung differ between controls and COPD subjects, and whether changes in these correlate with airway obstruction. Explanted lung tissue was obtained from transplant donors, GOLD 2–3 COPD subjects, and GOLD 4 lung transplant recipients, and bronchoalveolar lavage (BAL) cells were obtained from non-smokers, healthy smokers, and GOLD 1–3 COPD subjects. Iron-positive cells were quantified histologically, and the expression of iron uptake (transferrin and transferrin receptor), storage (ferritin) and export (ferroportin) genes was examined by real-time RT-PCR assay. Percentage of iron-positive cells and expression levels of iron metabolism genes were examined for correlations with airflow limitation indices (forced expiratory volume in the first second (FEV₁) and the ratio between FEV₁ and forced vital capacity (FEV₁/FVC)). The alveolar macrophage was identified as the predominant iron-positive cell type in lung tissues. Futhermore, the quantity of iron deposit and the percentage of iron positive macrophages were increased with COPD and emphysema severity. The mRNA expression of iron uptake and storage genes transferrin and ferritin were significantly increased in GOLD 4 COPD lungs compared to donors (6.9 and 3.22 fold increase, respectively). In BAL cells, the mRNA expression of transferrin, transferrin receptor and ferritin correlated with airway obstruction. These results support activation of an iron sequestration mechanism by alveolar macrophages in COPD, which we postulate is a protective mechanism against iron induced oxidative stress.

Chemosensory functions for pulmonary neuroendocrine cells

The mammalian airways are sensitive to inhaled stimuli, and airway diseases are characterized by hypersensitivity to volatile stimuli, such as perfumes, industrial solvents, and others. However, the identity and function of the cells in the airway that can sense volatile chemicals remain uncertain, particularly in humans. Here, we show that solitary pulmonary neuroendocrine cells (PNECs), which are morphologically distinct and physiologically undefined, might serve as chemosensory cells in human airways. This conclusion is based on our finding that some human PNECs expressed members of the olfactory receptor (OR) family in vivo and in primary cell culture, and are anatomically positioned in the airway epithelium to respond to inhaled volatile chemicals. Furthermore, apical exposure of primary-culture human airway epithelial cells to volatile chemicals decreased levels of serotonin in PNECs, and the led to the release of the neuropeptide calcitonin gene-related peptide (CGRP) to the basal medium. These data suggest that volatile stimulation of PNECs can lead to the secretion of factors that are capable of stimulating the corresponding receptors in the lung epithelium. We also found that the distribution of serotonin and neuropeptide receptors may change in chronic obstructive pulmonary disease, suggesting that increased PNEC-dependent chemoresponsiveness might contribute to the altered sensitivity to volatile stimuli in this disease. Together, these data indicate that human airway epithelia harbor specialized cells that respond to volatile chemical stimuli, and may help to explain clinical observations of odorant-induced airway reactions.

Noninvasive imaging of focal atherosclerotic lesions using fluorescence molecular tomography

Insights into the etiology of stroke and myocardial infarction suggest that rupture of unstable atherosclerotic plaque is the precipitating event. Clinicians lack tools to detect lesion instability early enough to intervene, and are often left to manage patients empirically, or worse, after plaque rupture. Noninvasive imaging of the molecular events signaling prerupture plaque progression has the potential to reduce the morbidity and mortality associated with myocardial infarction and stroke by allowing early intervention. Here, we demonstrate proof-of-principle in vivo molecular imaging of C-type natriuretic peptide receptor in focal atherosclerotic lesions in the femoral arteries of New Zealand white rabbits using a custom built fiber-based, fluorescence molecular tomography (FMT) system. Longitudinal imaging showed changes in the fluorescence signal intensity as the plaque progressed in the air-desiccated vessel compared to the uninjured vessel, which was validated by ex vivo tissue studies. In summary, we demonstrate the potential of FMT for noninvasive detection of molecular events leading to unstable lesions heralding plaque rupture.

Long-term IL-33-producing epithelial progenitor cells in chronic obstructive lung disease

Chronic obstructive lung disease is characterized by persistent abnormalities in epithelial and immune cell function that are driven, at least in part, by infection. Analysis of parainfluenza virus infection in mice revealed an unexpected role for innate immune cells in IL-13-dependent chronic lung disease, but the upstream driver for the immune axis in this model and in humans with similar disease was undefined. We demonstrate here that lung levels of IL-33 are selectively increased in postviral mice with chronic obstructive lung disease and in humans with very severe chronic obstructive pulmonary disease (COPD). In the mouse model, IL-33/IL-33 receptor signaling was required for Il13 and mucin gene expression, and Il33 gene expression was localized to a virus-induced subset of airway serous cells and a constitutive subset of alveolar type 2 cells that are both linked conventionally to progenitor function. In humans with COPD, IL33 gene expression was also associated with IL13 and mucin gene expression, and IL33 induction was traceable to a subset of airway basal cells with increased capacities for pluripotency and ATP-regulated release of IL-33. Together, these findings provide a paradigm for the role of the innate immune system in chronic disease based on the influence of long-term epithelial progenitor cells programmed for excess IL-33 production.

Nanoparticle PET/CT imaging of natriuretic peptide clearance receptor in prostate cancer

Atrial natriuretic peptide has been recently discovered to have anticancer effects via interaction with cell surface natriuretic peptide receptor A (NPRA) and natriuretic peptide clearance receptor (NPRC). In a preclinical model, NPRA expression has been identified during tumor angiogenesis and may serve as a potential prognostic marker and target for prostate cancer (PCa) therapy. However, the presence of NPRC receptor in the PCa model has not yet been assessed. Furthermore, there is still no report using nanoparticle for PCa positron emission tomography (PET) imaging. Herein, an amphiphilic comb-like nanoparticle was synthesized with controlled properties through modular construction containing C-atrial natriuretic factor (CANF) for NPRC receptor targeting and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator for high specific activity Cu-64 radiolabeling. The pharmacokinetics of (64)Cu-CANF-Comb exhibited tuned biodistribution and optimized in vivo profile in contrast to the nontargeted (64)Cu-Comb nanoparticle. PET imaging with (64)Cu-CANF-Comb in CWR22 PCa tumor model showed high blood pool retention, low renal clearance, enhanced tumor uptake, and decreased hepatic burden relative to the nontargeted (64)Cu-Comb. Immunohistochemistry staining confirmed the presence of NPRC receptor in tumor tissue. Competitive PET receptor blocking study demonstrated the targeting specificity of (64)Cu-CANF-Comb to NPRC receptor in vivo. These results establish a new nanoagent for prostate cancer PET imaging.

Chronic treatment in vivo with β-adrenoceptor agonists induces dysfunction of airway β(2) -adrenoceptors and exacerbates lung inflammation in mice

BACKGROUND AND PURPOSE

Inhalation of a β-adrenoceptor agonist (β-agonist) is first-line asthma therapy, used for both prophylaxis against, and acute relief of, bronchoconstriction. However, repeated clinical use of β-agonists leads to impaired bronchoprotection and, in some cases, adverse patient outcomes. Mechanisms underlying this β(2) -adrenoceptor dysfunction are not well understood, due largely to the lack of a comprehensive animal model and the uncertainty as to whether or not bronchorelaxation in mice is mediated by β(2) -adrenoceptors. Thus, we aimed to develop a mouse model that demonstrated functional β-agonist-induced β(2) -adrenoceptor desensitization in the context of allergic inflammatory airway disease.

EXPERIMENTAL APPROACH

We combined chronic allergen exposure with repeated β-agonist inhalation in allergen-treated BALB/C mice and examined the contribution of β(2) -adrenoceptors to albuterol-induced bronchoprotection using FVB/NJ mice with genetic deletion of β(2) -adrenoceptors (KO). Associated inflammatory changes - cytokines (ELISA), cells in bronchoalevolar lavage and airway remodelling (histology) and β(2) -adrenoceptor density (radioligand binding) - were also measured. KEY RESULTS β(2) -Adrenoceptors mediated albuterol-induced bronchoprotection in mice. Chronic treatment with albuterol induced loss of bronchoprotection, associated with exacerbation of the inflammatory components of the asthma phenotype.

CONCLUSIONS AND IMPLICATIONS

This animal model reproduced salient features of human asthma and linked loss of bronchoprotection with airway pathobiology. Accordingly, the model offers an advanced tool for understanding the mechanisms of the effects of chronic β- agonist treatment on β-adrenoceptor function in asthma. Such information may guide the clinical use of β-agonists and provide insight into development of novel β-adrenoceptor ligands for the treatment of asthma.

Small-airway obstruction and emphysema in chronic obstructive pulmonary disease

BACKGROUND

The major sites of obstruction in chronic obstructive pulmonary disease (COPD) are small airways (<2 mm in diameter). We wanted to determine whether there was a relationship between small-airway obstruction and emphysematous destruction in COPD.

METHODS

We used multidetector computed tomography (CT) to compare the number of airways measuring 2.0 to 2.5 mm in 78 patients who had various stages of COPD, as judged by scoring on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) scale, in isolated lungs removed from patients with COPD who underwent lung transplantation, and in donor (control) lungs. MicroCT was used to measure the extent of emphysema (mean linear intercept), the number of terminal bronchioles per milliliter of lung volume, and the minimum diameters and cross-sectional areas of terminal bronchioles.

RESULTS

On multidetector CT, in samples from patients with COPD, as compared with control samples, the number of airways measuring 2.0 to 2.5 mm in diameter was reduced in patients with GOLD stage 1 disease (P=0.001), GOLD stage 2 disease (P=0.02), and GOLD stage 3 or 4 disease (P<0.001). MicroCT of isolated samples of lungs removed from patients with GOLD stage 4 disease showed a reduction of 81 to 99.7% in the total cross-sectional area of terminal bronchioles and a reduction of 72 to 89% in the number of terminal bronchioles (P<0.001). A comparison of the number of terminal bronchioles and dimensions at different levels of emphysematous destruction (i.e., an increasing value for the mean linear intercept) showed that the narrowing and loss of terminal bronchioles preceded emphysematous destruction in COPD (P<0.001).

CONCLUSIONS

These results show that narrowing and disappearance of small conducting airways before the onset of emphysematous destruction can explain the increased peripheral airway resistance reported in COPD. (Funded by the National Heart, Lung, and Blood Institute and others.).

Elastase inhibitory activity of airway α1-antitrypsin is protected by treatment with a catalytic antioxidant in a baboon model of severe bronchopulmonary dysplasia

Recent studies in animal models of bronchopulmonary dysplasia (BPD) suggest that antioxidant treatments may be beneficial for the disease. However, the mechanisms by which these drugs improve the course of BPD are not completely known. Alpha1-antitrypsin (α1-AT) is one of the major serine protease inhibitors in human plasma that has antielastase and antiapoptotic activities. Both activities of α1-AT are dependent on its reactive site loop (RSL), which is highly susceptible to oxidative inactivation. In this study, we investigated the elastase inhibitory activity of α1-AT in two different baboon models of BPD, the "new BPD" and the "severe BPD" models, and determined the effect of treatment with a catalytic antioxidant, Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP), on the elastase inhibitory activity of α1-AT in the severe BPD model. Our results demonstrate the presence of sufficient elastase inhibitory activity of the airway α1-AT in the new but not in the severe BPD model. Treatment of severe BPD group baboons with the catalytic antioxidant MnTE-2-PyP resulted in augmentation of the elastase inhibitory activity of α1-AT. These findings suggest that prevention of the oxidative inactivation of α1-AT may be one of the mechanisms by which antioxidant therapy improves the pulmonary outcomes in animal models of severe BPD.

Laparoscopic Dor versus Toupet fundoplication following Heller myotomy for achalasia: results of a multicenter, prospective, randomized-controlled trial

BACKGROUND

The type of fundoplication that should be performed in conjunction with Heller myotomy for esophageal achalasia is controversial. We prospectively compared anterior fundoplication (Dor) with partial posterior fundoplication (Toupet) in patients undergoing laparoscopic Heller myotomy.

METHODS

A multicenter, prospective, randomized-controlled trial was initiated to compare Dor versus Toupet fundoplication after laparoscopic Heller myotomy. Outcome measures were symptomatic GERD scores (0-4, five-point Likert scale questionnaire) and 24-h pH testing at 6-12 months after surgery. Data are mean ± SD. Statistical analysis was by Mann-Whitney U test, Wilcoxon signed rank test, and Freidman's test.

RESULTS

Sixty of 85 originally enrolled and randomized patients who underwent 36 Dor and 24 Toupet fundoplications had follow-up data per protocol for analysis. Dor and Toupet groups were similar in age (46.8 vs. 51.7 years) and gender (52.8 vs. 62.5% male). pH studies at 6-12 months in 43 patients (72%: Dor n = 24 and Toupet n = 19) showed total DeMeester scores and % time pH < 4 were not significant between the two groups. Abnormal acid reflux was present in 10 of 24 Dor group patients (41.7%) and in 4 of 19 Toupet patients (21.0%) (p = 0.152). Dysphagia and regurgitation symptom scores improved significantly in both groups compared to preoperative scores. No significant differences in any esophageal symptoms were noted between the two groups preoperatively or at follow-up. SF-36 quality-of-life measures changed significantly from pre- to postoperative for five of ten domains in the Dor group and seven of ten in the Toupet patients (not significant between groups).

CONCLUSION

Laparoscopic Heller myotomy provides significant improvement in dysphagia and regurgitation symptoms in achalasia patients regardless of the type of partial fundoplication. Although a higher percentage of patients in the Dor group had abnormal 24-h pH test results compared to those of patients who underwent Toupet, the differences were not statistically significant.

Imaging alveolar-duct geometry during expiration via ³He lung morphometry

Acinar geometry has been the subject of several morphological and imaging studies in the past; however, surprisingly little is known about how the acinar microstructure changes when the lung inflates or deflates. Lung morphometry with hyperpolarized (3)He diffusion MRI allows non-destructive evaluation of lung microstructure and acinar geometry, which has important applications in understanding basic lung physiology and disease. In this study, we have measured the alveolar and acinar duct sizes at physiologically relevant volumes by (3)He lung morphometry in six normal, excised, and unfixed canine lungs. Our results imply that, during a 37% decrease in lung volume, the acinar duct radius decreases by 19%, whereas the alveolar depth increases by 9% (P < 0.0001 and P < 0.05, respectively via paired t-tests with a Bonferroni correction). A comparison to serial sections under the microscope validates the imaging results and opens the door to in vivo human studies of lung acinar geometry and physiology during respiration using (3)He lung morphometry.

The role of matrix metalloproteinase-9 in cigarette smoke-induced emphysema

RATIONALE

Matrix metalloprotease (MMP)-9 is an elastolytic endopeptidase produced by activated macrophages that may be involved in the development of human pulmonary emphysema and could be inhibited with existing compounds. Mouse models have demonstrated that excess MMP-9 production can result in permanent alveolar destruction.

OBJECTIVES

To determine if MMP-9 causes cigarette smoke-induced emphysema using MMP-9 knockout mice and human samples.

METHODS

Mouse lungs were analyzed for inflammation and airspace enlargement using a mainstream smoke-exposure model. Human macrophage mRNA was isolated from subjects with emphysema by laser capture microdissection. Human blood monocyte mRNA was isolated from subjects with greater than 30 pack-year smoking history. Human gene expression was determined by quantitative polymerase chain reaction and compared with emphysema severity determined by automated computed tomography analysis. Plasma Clara cell secretory protein and surfactant protein-D were quantified to measure ongoing lung injury.

MEASUREMENTS AND MAIN RESULTS

Mice deficient in MMP-9 develop the same degree of cigarette smoke-induced inflammation and airspace enlargement as strain-matched controls. Macrophages are the predominant source of MMP-9 production in human emphysema specimens and similar quantities of macrophage MMP-9 mRNA is present in areas of lung with and without emphysema. Circulating monocytes produce more MMP-9 in individuals with advanced emphysema severity despite no correlation of MMP-9 with markers of ongoing lung damage.

CONCLUSIONS

These results suggest that MMP-9 in humans who smoke is similar to smoke-exposed mice, where MMP-9 is present in emphysematous lung but not correlated with the emphysema. To the degree that the mechanisms of emphysema in humans who smoke resemble the mouse model, these data suggest specific inhibition of MMP-9 is unlikely to be an effective therapy for cigarette smoke-induced emphysema. Clinical trial registered with www.clinicaltrials.gov (NCT 00757120).

Oxidative and nitrosative modifications of tropoelastin prevent elastic fiber assembly in vitro

Elastic fibers are extracellular structures that provide stretch and recoil properties of tissues, such as lungs, arteries, and skin. Elastin is the predominant component of elastic fibers. Tropoelastin (TE), the precursor of elastin, is synthesized mainly during late fetal and early postnatal stages. The turnover of elastin in normal adult tissues is minimal. However, in several pathological conditions often associated with inflammation and oxidative stress, elastogenesis is re-initiated, but newly synthesized elastic fibers appear abnormal. We sought to determine the effects of reactive oxygen and nitrogen species (ROS/RNS) on the assembly of TE into elastic fibers. Immunoblot analyses showed that TE is oxidatively and nitrosatively modified by peroxynitrite (ONOO(-)) and hypochlorous acid (HOCl) and by activated monocytes and macrophages via release of ONOO(-) and HOCl. In an in vitro elastic fiber assembly model, oxidatively modified TE was unable to form elastic fibers. Oxidation of TE enhanced coacervation, an early step in elastic fiber assembly, but reduced cross-linking and interactions with other proteins required for elastic fiber assembly, including fibulin-4, fibulin-5, and fibrillin-2. These findings establish that ROS/RNS can modify TE and that these modifications affect the assembly of elastic fibers. Thus, we speculate that oxidative stress may contribute to the abnormal structure and function of elastic fibers in pathological conditions.

Quantitative assessment of lung microstructure in healthy mice using an MR-based 3He lung morphometry technique

The recently developed technique of lung morphometry using hyperpolarized (3)He diffusion magnetic resonance (MR) (Yablonskiy DA, Sukstanskii AL, Woods JC, Gierada DS, Quirk JD, Hogg JC, Cooper JD, Conradi MS. J Appl Physiol 107: 1258-1265, 2009) permits in vivo study of lung microstructure at the alveolar level. Originally proposed for human lungs, it also has the potential to study small animals. The technique relies on theoretical developments in the area of gas diffusion in lungs linking the diffusion attenuated MR signal to the lung microstructure. To adapt this technique to small animals, certain modifications in MR protocol and data analysis are required, reflecting the smaller size of mouse alveoli and acinar airways. This is the subject of the present paper. Herein, we established empirical relationships relating diffusion measurements to geometrical parameters of lung acinar airways with dimensions typical for mice and rats by using simulations of diffusion in the airways. We have also adjusted the MR protocol to acquire data with much shorter diffusion times compared with humans to accommodate the substantially smaller acinar airway length. We apply this technique to study mouse lungs ex vivo. Our MR-based measurements yield mean values of lung surface-to-volume ratio of 670 cm(-1), alveolar density of 3,200 per mm(3), alveolar depth of 55 μm, and mean chord length of 62 μm, all consistent with published data obtained histologically in mice by unbiased methods. The proposed technique can be used for in vivo experiments, opening a door for longitudinal studies of lung morphometry in mice and other small animals.

Microfibril-associated glycoprotein-1, an extracellular matrix regulator of bone remodeling

MAGP1 is an extracellular matrix protein that, in vertebrates, is a ubiquitous component of fibrillin-rich microfibrils. We previously reported that aged MAGP1-deficient mice (MAGP1Delta) develop lesions that are the consequence of spontaneous bone fracture. We now present a more defined bone phenotype found in MAGP1Delta mice. A longitudinal DEXA study demonstrated age-associated osteopenia in MAGP1Delta animals and muCT confirmed reduced bone mineral density in the trabecular and cortical bone. Further, MAGP1Delta mice have significantly less trabecular bone, the trabecular microarchitecture is more fragmented, and the diaphyseal cross-sectional area is significantly reduced. The remodeling defect seen in MAGP1Delta mice is likely not due to an osteoblast defect, because MAGP1Delta bone marrow stromal cells undergo osteoblastogenesis and form mineralized nodules. In vivo, MAGP1Delta mice exhibit normal osteoblast number, mineralized bone surface, and bone formation rate. Instead, our findings suggest increased bone resorption is responsible for the osteopenia. The number of osteoclasts derived from MAGP1Delta bone marrow macrophage cells is increased relative to the wild type, and osteoclast differentiation markers are expressed at earlier time points in MAGP1Delta cells. In vivo, MAGP1Delta mice have more osteoclasts lining the bone surface. RANKL (receptor activator of NF-kappaB ligand) expression is significantly higher in MAGP1Delta bone, and likely contributes to enhanced osteoclastogenesis. However, bone marrow macrophage cells from MAGP1Delta mice show a higher propensity than do wild-type cells to differentiate to osteoclasts in response to RANKL, suggesting that they are also primed to respond to osteoclast-promoting signals. Together, our findings suggest that MAGP1 is a regulator of bone remodeling, and its absence results in osteopenia associated with an increase in osteoclast number.

Highly conserved transcriptional responses to mechanical ventilation of the lung

Cross-species analysis of microarray data has shown improved discriminating power between healthy and diseased states. Computational approaches have proven effective in deciphering the complexity of human disease by identifying upstream regulatory elements and the transcription factors that interact with them. Here we used both methods to identify highly conserved transcriptional responses during mechanical ventilation, an important therapeutic treatment that has injurious side effects. We generated control and ventilated whole lung samples from the premature baboon model of bronchopulmonary dysplasia (BPD), processed them for microarray, and combined them with existing whole lung oligonucleotide microarray data from 85 additional control samples from mouse, rat, and human and 19 additional ventilated samples from mouse and rat. Of the 2,531 orthologs shared by all 114 samples, 60 were modulated by mechanical ventilation [false discovery rate (FDR)-adjusted q value (q(FDR)) = 0.005, ANOVA]. These included transcripts encoding the transcription factors ATF3 and FOS. Because of compelling known roles for these transcription factors, we used computational methods to predict their targets in the premature baboon model of BPD, which included elastin (ELN), gastrin-releasing polypeptide (GRP), and connective tissue growth factor (CTGF). This approach identified highly conserved transcriptional responses to mechanical ventilation and may facilitate identification of therapeutic targets to reduce the side effects of this valuable treatment.

Clinical predictors of operative complexity in laparoscopic ventral hernia repair: a prospective study

BACKGROUND

Because of uncertainties about the complexity of laparoscopic ventral hernia repair for varying patient populations, surgeons may be reluctant to perform this procedure. This study aimed to delineate the risk factors that can be identified in the preoperative setting predictive of longer operative times and complexity in laparoscopic ventral hernia repair.

METHODS

Patient demographics including body mass index (BMI), comorbidities, previous laparoscopic and open surgical procedures, ventral hernia repairs, and hernia characteristics (defect size and location, adhesions, incarceration) were recorded prospectively. Data are given as mean +/- standard deviation. Times (min) required for abdominal access, adhesiolysis, and mesh placement as well as the total operative time were recorded during each case as outcome measures of operative difficulty. Univariate analyses were performed with the t-test or the Mann-Whitney U test as well as multivariate analyses using the stepwise analysis of covariance model to determine demographic and clinical variables influencing operative times.

RESULT

The study enrolled 180 patients (78 men and 102 women) with a mean age of 54.8 +/- 12.2 years and a mean BMI of 33.3 +/- 13.0 kg/m(2). Multivariate analysis demonstrated significantly longer (p < 0.05) adhesiolysis and total operative times for patients with prior ventral hernia repairs, suprapubic hernia, bowel adhesion to the abdominal wall or hernia sac, and larger hernia defect. The total operative time also was increased (p < 0.05) with incarcerated hernia contents. Mesh placement time was increased (p < 0.05) with incarcerated hernia contents, suprapubic hernia location, hernias requiring larger mesh for repair, and decreased postgraduate year of the surgical assistant. The time required to obtain abdominal access was longer (p < 0.05) with a greater BMI and a higher American Society of Anesthesiology (ASA) classification. The operative times were not increased with a history of peritonitis, diabetes, immunosuppression, cancer, or with higher numbers of previous open or laparoscopic surgeries.

CONCLUSIONS

At least 10 preoperatively identifiable patient variables, either alone or in combination, are predictive of prolonged operative times during laparoscopic ventral hernia repair and may be used as surrogates to determine the complexity of a minimally invasive approach.

Differential expression of tissue repair genes in the pathogenesis of chronic obstructive pulmonary disease

RATIONALE

The airflow limitation that defines severity of chronic obstructive pulmonary disease (COPD) is caused by a combination of small airway obstruction and emphysematous lung destruction.

OBJECTIVES

To examine the hypothesis that small airway obstructive and emphysematous destructive lesions are produced by differential expression of genes associated with tissue repair.

METHODS

The expression of 54 genes associated with repair of repetitively damaged tissue was measured in 136 paired samples of small bronchioles and surrounding lung tissue separated by laser capture microdissection. These samples were collected from 63 patients at different levels of disease severity who required surgery for either lung cancer or lung transplantation for very severe COPD. Gene expression was measured by quantitative polymerase chain reaction in these paired samples and compared with the FEV(1) by linear regression analysis.

MEASUREMENTS AND MAIN RESULTS

After corrections for false discovery rates, only 2 of 10 genes (serpin peptidase inhibitor/plasminogen activator inhibitor member 2 and matrix metalloproteinase [MMP] 10) increased, whereas 8 (MMP2, integrin-alpha1, vascular endothelial growth factor, a disintegrin and metallopeptidase domain 33, scatter factor/hepatocyte growth factor, tissue inhibitor of matrix metalloproteinase-2, fibronectin, and collagen 3alpha1) decreased in small airways in association with FEV(1). In contrast, 8/12 genes (early growth response factor 1, MMP1, MMP9, MMP10, plasminogen activator urokinase, plasminogen activator urokinase receptor, tumor necrosis factor, and IL13) increased and 4/12 (MMP2, tissue inhibitor of matrix metalloproteinase-1, collagen 1alpha1, and transforming growth factor-beta3) decreased in the surrounding lung tissue in association with progression of COPD.

CONCLUSIONS

The progression of COPD is associated with the differential expression of a cluster of genes that favor the degradation of the tissue surrounding the small conducting airways.

Equal BMD after daily or triweekly exercise in growing rats

The purpose of this study was to examine the efficacy of continuous resistance training (3 days/wk) compared to interrupted resistance training where 20-24 h separated an exercise bout (i. e. 6 days/wk) for enhancing bone mineral density (BMD) in growing male rats. The total volume of work performed per week between the two resistance training programs was equivalent by design. Young male rats were randomly divided into Control (Con, n=9), 3 days/wk resistance trained group (RT3, n=9), and 6 days/wk resistance trained group (RT6, n=9). The RT3 and RT6 groups were conditioned to climb a vertical ladder with weights appended to their tail for a total of 6 wks. After 6 wks, BMD (assessed via DXA) from the left tibia was significantly greater for RT3 (0.242+/-0.004 g/cm (2)) and RT6 (0.244+/-0.004 g/cm (2)) compared to Con (0.226+/-0.003 g/cm (2)). Further, serum osteocalcin (oc, in ng/ml) was significantly greater for RT3 (75.8+/-4.4) and RT6 (73.5+/-3.8) compared to Con (53.4+/-2.4). There was no significant difference in BMD or serum OC between RT3 and RT6 groups. The results indicate that both resistance training programs were equally effective in elevating bone mineral density in young, growing rats.

Cigarette smoke induces nucleic-acid oxidation in lung fibroblasts

Oxidative stress is widely proposed as a pathogenic mechanism for chronic obstructive pulmonary disease (COPD), but the molecular pathway connecting oxidative damage to tissue destruction remains to be fully defined. We suggest that reactive oxygen species (ROS) oxidatively damage nucleic acids, and this effect requires multiple repair mechanisms, particularly base excision pathway components 8-oxoguanine-DNA glycosylase (OGG1), endonuclease III homologue 1 (NTH1), and single-strand-selective monofunctional uracil-DNA glycosylase 1 (SMUG1), as well as the nucleic acid-binding protein, Y-box binding protein 1 (YB1). This study was therefore designed to define the levels of nucleic-acid oxidation and expression of genes involved in the repair of COPD and in corresponding models of this disease. We found significant oxidation of nucleic acids localized to alveolar lung fibroblasts, increased levels of OGG1 mRNA expression, and decreased concentrations of NTH1, SMUG1, and YB1 mRNA in lung samples from subjects with very severe COPD compared with little or no COPD. Mice exposed to cigarette smoke exhibited a time-dependent accumulation of nucleic-acid oxidation in alveolar fibroblasts, which was associated with an increase in OGG1 and YB1 mRNA concentrations. Similarly, human lung fibroblasts exposed to cigarette smoke extract exhibited ROS-dependent nucleic-acid oxidation. The short interfering RNA (siRNA)-dependent knockdown of OGG1 and YB1 expression increased nucleic-acid oxidation at the basal state and after exposure to cigarette smoke. Together, our results demonstrate ROS-dependent, cigarette smoke-induced nucleic-acid oxidation in alveolar fibroblasts, which may play a role in the pathogenesis of emphysema.