Search

Pleural epithelial adaptations to mechanical stress are relevant to both normal lung function and parenchymal lung diseases. Assessing regional differences in mechanical stress, however, has been complicated by the nonlinear stress-strain properties of the lung and the large displacements with ventilation. Moreover, there is no reliable method of isolating pleural epithelium for structural studies. To define the topographic variation in pleural structure, we developed a method of en face harvest of murine pleural epithelium. Silver-stain was used to highlight cell borders and facilitate imaging with light microscopy. Machine learning and watershed segmentation were used to define the cell area and cell perimeter of the isolated pleural epithelial cells. In the deflated lung at residual volume, the pleural epithelial cells were significantly larger in the apex (624 ± 247 μm

BackgroundResection of colorectal liver metastasis (CLM) is beneficial when feasible. However, the benefit of second hepatectomy for hepatic recurrence in CLM remains unclear.MethodsThe Colorectal Liver Operative Metastasis International Collaborative retrospectively examined 1004 CLM cases from 2000 to 2018 from a total of 953 patients. Hepatic recurrence after initial hepatectomy was identified in 218 patients. Kaplan-Meier analysis was performed for overall survival (OS) and recurrence-free survival (RFS). Propensity score matching (PSM) was performed to offset selection bias. Cox proportional-hazards regression was performed to identify risk factors associated with OS.ResultsA total of 51 patients underwent second hepatectomy. Unadjusted median OS was 60.1 months in repeat-hepatectomy versus 38.3 months in the single-hepatectomy group (p = 0.015). In the PSM population, median OS remained significantly better in the repeat-hepatectomy group (60.1 vs. 33.1 months; p = 0.0023); median RFS was 12.4 months for the repeat-hepatectomy group, versus 9.8 months in the single-hepatectomy group (p = 0.0050). Repeat hepatectomy was associated with lower risk of death (hazard ratio: 0.283; p = 0.000012). Obesity, tobacco use, and high intraoperative blood loss were associated with significant risk of death (p

BACKGROUND. Malignant peritoneal mesothelioma (MPM) is a rare diagnosis with a dismal prognosis if untreated. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is shown to significantly improve survival. Our institution is uniquely positioned to report long-term outcomes in MPM with CRS-HIPEC, due to our robust peritoneal surface disease program existing over the past three decades. METHODS. Our prospectively maintained, single-institution database of CRS-HIPEC cases was reviewed, identifying 111 consecutive patients with MPM over 28 years (1993–2021). Prognostic, operative, and pathologic factors were reviewed. Overall survival (OS) and conditional survival (CS) analyses were performed. RESULTS. The average age was 55.1 years; 58.6% of patients were male; 17 of 111 patients (15.3%) had a second CRS-HIPEC. At first CRS-HIPEC, the average PCI score was 18.7, and the perfusate drugs were platinum-based (72.1%) and mitomycin C (27.9%). The resection status at first CRS-HIPEC was R2a (46.4%), followed by R0–1 (29.1%), and R2b-c (24.5%). Median OS was 3.3 years for the entire cohort, with 75th and 25th percentiles at 10.7 months and 10.6 years. Median CS was improved if patients survived to the 1-year postoperative mark (4.9 years, p < 0.01) and trended toward further improvement with each passing year. If 3-year postoperative survival was achieved, the median CS improved to 6.1 years. CONCLUSIONS. This represents one of the largest and lengthiest, single-center, longitudinal, case series of peritoneal mesothelioma treated with CRS-HIPEC. The OS suggests efficacy for CRS-HIPEC for MPM. Long-term survival improves significantly after patients achieve the 1-year, postoperative mark.

Cytoreductive surgery (CRS) is at the forefront of treatment for colorectal cancer with peritoneal metastasis or "carcinomatosis" (CRC-PC). We report outcomes of the operative management of CRC-PC at a single center.We retrospectively reviewed our database from 1992 through 2021. The Kaplan-Meier method was used to estimate survival. Proportional hazards regression and multivariable models were used for assessments.This study included 345 patients with mean age 53.5 years. Multivariate analysis revealed performance and resection status were associated with overall survival (OS; p0.001). Within the R0/R1 group, adverse impact on OS was found with increasing Peritoneal Cancer Index (PCI) score starting at 9 (hazard ratio [HR] = 1.98, CI 1.39-2.82, p = 0.0001) with the most significant hazard noted at PCI14 (HR = 2.35, CI 1.52-3.63, p = 0.0001). Incomplete resection (R2) had significantly worse OS compared with complete CRS 33.4 (n = 206) vs R2: 12.7 months (n = 139; p0.0001. When stratified by PCI for the R0/R1 group, median OS for PCI less than 10, 10 to 15, and greater than 15 was 38.2, 19.7, and 22.2 m, respectively (p = 0.0007 comparing PCI less than 10 and greater than 15). Ten-year increments-1991 through 2000, 2001 through 2010, 2011 through 2020-revealed improvement in median OS (13.4 [n = 66], 19.3 [n = 139], and 29.1 months [n = 140]). However, by resection status, median OS remained stable for R0/R1 (32.3 [n = 23], 31.1 [n = 76], and 34.1 months [n = 107]) and improved for R2 (5.2 [n = 43], 14.4 [n = 63], and 14.6 months [n = 33]). Clavien-Dindo complication rate (greater than or equal to grade III) was 29.4%.CRS improves outcomes for CRC-PC compared with historic outcomes with nonoperative management. This benefit is greatest with complete resection and lower disease burden. Results of CRS (with or without heated intraperitoneal chemotherapy) are improving, and surgery for CRC-PC should be routinely considered.

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is an effective surgical intervention for peritoneal surface malignancy. The effect of myometrium invasion on outcomes is unknown.Retrospective review of our institutional registry with analysis of CRS-HIPEC cases involving a hysterectomy. Compared cases with myometrium invasion versus those without invasion. Primary outcome was survival as measured by overall survival (OS) and disease-free survival (DFS). Secondary outcome was the evaluation of risk factors for myometrium invasion based on multivariate analysis.A total of 126 cases of CRS-HIPEC involving a hysterectomy were identified. Ninety-seven cases (76.9%) had no myometrium invasion and the remaining 29 cases (23.1%) had malignant invasion. The presence of myometrial invasion was a significant negative survival prognostic factor. The OS was halved with mean survival times of 2.8 (±2.3) versus 5.8 (±4.7) years for cases with and without invasion, respectively (p = 0.002). Five-year OS rates were also inferior with myometrium invasion at 17.4% versus 53.8% (odds ratio [OR] = 0.181, 95% confidence interval [CI]: 0.057-0.580, p = 0.002). A similar trend was present with DFS with mean survival times of 1.4 (±0.9) versus 3.7 (±3.9) years for noninvasion and invasion cases (p = 0.009). The 5-year DFS rates were 0% versus 34.8% (OR = 0.652, 95% CI: 0.549-0.775, p = 0.004). Secondary analysis significantly associated several risk factors with myometrium invasion to include lymph node positivity (OR = 2.539, 95% CI: 1.074-6.003, p = 0.012), colorectal primary tumors (OR = 2.248, 95% CI: 1.094-5.161, p = 0.035), and high-grade tumors (OR = 2.160, 95% CI: 1.080-4.820, p = 0.038).Myometrium invasion is a significant negative prognostic factor for survival following CRS-HIPEC. Several risk factors are potentially predictive of identifying those at high-risk for myometrium invasion.

Hepatobiliary malignancies present with advanced disease precluding upfront resection. Liver-directed therapy (LDT), particularly Y-90 radioembolization and transarterial chemoembolization (TACE), has become increasingly utilized to facilitate attempt at oncologic resection. However, the safety profile of preoperative LDT is limited.Retrospective review of the ACS NSQIP main and targeted hepatectomy registries for 2014-2016. Primary objective was evaluation of outcomes between preoperative LDT cases and those that received upfront resection.A total of 8923 cases met selection criteria. 192 cases (2.15%) received either Y-90 or TACE prior to hepatectomy. Multivariate analysis for all study patients revealed preoperative LDT significantly increased the risk of perioperative transfusion (OR 2.19, 95% CI 1.445-3.328, P 0.0001), sepsis (OR 2.21, 95% CI 1.104-4.411, P = 0.022), and liver failure (OR 2.72, 95% CI 1.562-4.747, P 0.0001). Subgroup analysis found for primary hepatobiliary malignancies LDT only increased the risk for liver failure. While for secondary hepatic tumors LDT significantly increased perioperative transfusion, sepsis, cardiac failure, renal failure, liver failure, and mortality. The complication profile also significantly increased with advanced T stage. Conversely, on propensity score matching preoperative LDT did not significantly increase perioperative complications.Preoperative LDT has the potential to convert inoperable hepatic tumors into resectable disease but there is a general increased risk for significant postoperative complications, most notable liver failure. However, on controlled analysis preoperative LDT does not increase perioperative complications and should not be considered a contraindication to resection.

BACKGROUND. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) improves survival in abdominal cancer patients with metastatic disease limited to the peritoneal cavity. Patients are increasingly being offered repeat CRS-HIPECs for peritoneal recurrence. However, in this rare clinical scenario, the survival benefit of performing repeat CRS-HIPEC operations remains unclear. METHODS. A retrospective review of the CRS-HIPEC database at Wake Forest Baptist Medical Center was performed over a 30-year timespan. From 1547 patients with appendix cancers, colorectal cancers, mesotheliomas, and other miscellaneous cancers, 156 received more than one CRS-HIPEC. Kaplan-Meier survival analysis was performed using overall survival (OS) from the time of surgery as the primary endpoint. Multi-variable Cox proportional hazards regression modelling was performed on pertinent clinical variables. RESULTS. Patients who received multiple CRS-HIPECs had significantly better median OS (10.7 years) versus those who received one CRS-HIPEC (2.5 years), with appendix cancers faring best (12.9 years). Resection status R2a or better was achieved in 76.4% of repeat CRS-HIPECs. There were no significant changes in complication rates after repeat CRS-HIPEC. On multivariate analysis of repeat CRS-HIPEC, patients with appendix and colorectal cancers, heart disease, and poor functional status were independently associated with poor OS. Factors not independently associated with OS were age, sex, body mass index, race, diabetes, lung disease, smoking history, and systemic chemotherapy between CRS-HIPECs. CONCLUSIONS. Performing multiple CRS-HIPEC operations on appropriate surgical candidates may significantly prolong survival. Appendix cancers derived the greatest benefit. Satisfactory resection margins and complication rates are comparable to first cases and achievable in repeat CRS-HIPEC procedures.

BACKGROUND. Low-grade appendiceal mucinous neoplasm (LAMN) with peritoneal involvement is a common indication for cytoreductive surgery with heated intraperitoneal chemotherapy (CRS/HIPEC). With peritoneal recurrence, patients are increasingly being offered repeat CRS/HIPECs, however optimal timing for a second CRS/HIPEC remains unknown. METHODS. A prospectively maintained 30-year database at our high-volume HIPEC center was analyzed retrospectively for patients with LAMNs and peritoneal recurrence receiving one or two CRS/HIPECs. Kaplan–Meier survival analysis, linear regression modeling, and Cox proportional hazards regression analyses were performed. RESULTS. Overall, 143 patients with LAMNs who underwent CRS/HIPECs had confirmed postoperative peritoneal recurrence. Of these patients, 85 underwent one CRS/HIPEC and 58 underwent two CRS/HIPECs. The groups had significant differences in age, with younger patients more likely to undergo a second CRS/HIPEC (48.5 vs. 58.0 years; p < 0.001). The median overall survival (OS) for the group undergoing two CRS/HIPECs was approximately four times longer compared with the group undergoing one CRS/HIPEC (227.1 vs. 54.5 months; p < 0.0001). The time from recurrence to the second CRS/HIPEC was not significantly associated with OS from the time of the first operation. Instead, a shorter time between the first CRS/HIPEC and recurrence was significantly associated with shorter OS from the time of the first operation (p = 0.037). CONCLUSION. In peritoneal LAMNs with recurrence, receiving two CRS/HIPECs was associated with better OS compared with receiving one CRS/HIPEC. Longer time to recurrence was a good prognostic factor. Delay between recurrence and second CRS/HIPEC had no apparent impact on OS from the first CRS/HIPEC; thus, immediate or delayed reoperative intervention are both reasonable approaches.

Primary laterality of colorectal cancer is thought to be associated with differences in outcomes. Liver metastasis is the most common site of solitary colorectal cancer spread. However, how primary colorectal cancer laterality affects outcomes in colorectal liver metastasis remains unclear.The Colorectal Liver Operative Metastasis International Collaborative (COLOMIC) of operative hepatectomy cases for colorectal liver metastasis was compiled from five participating institutions. This included consecutive cases from 2000 to 2018 at all sites. A total of 884 patients were included in this study. Univariate, multivariate, and Kaplan-Meier analyses were performed.Patients with left-sided versus right-sided cancers had significantly better overall survival: 49.4 vs. 41.8 months (p 0.05). Patients with KRAS mutations had significantly worse median overall survival compared to KRAS wild-type (43.6 vs 56.1 months; p 0.001). In left-sided cancers, KRAS mutations were associated with significantly worse median overall survival compared to KRAS wild-type cancers (43.6 vs 56.6 months; p 0.01). This association was absent in patients with right-sided primary tumors. Multivariate Cox regression analysis revealed different variable sets (non-overlapping) were associated with overall survival, when comparing left-sided and right-sided cancers.Understanding how primary tumor laterality and related biological aspects affect long-term outcomes can potentially inform treatment decisions for patients with colorectal liver metastases.

Metastatic progression occurs along the locoregional vasculature, and a common anatomic variant is an aberrant right hepatic artery (aRHA). This study evaluated the effect of an aRHA following pancreaticoduodenectomy, with a focus on hepatic metastases.This was a single-institution retrospective review of non-metastatic pancreatic cancer cases between 2012 and 2020. aRHA cases were compared with patients with conventional anatomy. The primary outcome was hepatic recurrence rates, while secondary analysis survival outcomes were measured by overall survival (OS) and disease-free survival (DFS). Subgroup analysis was stratified by tumor resectability and utilization of systemic therapy.Overall, 207 cases were reviewed, with 17.4% having aRHA anatomy. On multivariate analysis, aRHA increased hepatic recurrence for all-comers (odds ratio [OR] 4.76, 95% confidence interval [CI] 2.18-10.38; p 0.001). aRHA was significant for resectable tumors (OR 2.58, 95% CI 1.89-6.66; p = 0.045) and borderline resectable tumors (OR 28.88, 95% CI 5.52-151.18; p 0.0001) in regard to hepatic recurrence on univariate analysis. Increased hepatic recurrence correlated with decreased 3-year OS and DFS rates of 30.6% versus 50.3% (OR 0.44, 95% CI 0.20-0.94; p = 0.032) and 13.6% versus 36.9% (OR 0.27, 95% CI 0.08-0.97; p = 0.035). Systemic therapy limited the effects of aRHA.aRHA was associated with inferior survival outcomes due to the significantly increased risk of hepatic metastatic disease with aberrant anatomy. This study provides important prognostic information for a commonly encountered anatomic variant.

Conversion from low-grade to high-grade disease is known to occur following repeat cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC); however, the incidence rate, risk factors, and outcomes have not been studied.We conducted a retrospective review of multiple CRS/HIPEC cases for patients originally diagnosed with low-grade appendiceal neoplasms, and compared converted cases with non-converters. Primary outcomes were the incidence rate and risk factors for conversion, while secondary outcomes were effect on cytoreduction, overall survival (OS), and disease-free survival (DFS).Overall, 65 patients undergoing 134 cases of repeat CRS/HIPEC were identified; 11 patients converted to high-grade disease, an incidence rate of 16.92%. Converted cases averaged 4.4 years between CRS/HIPEC, versus 3.7 years for non-converters. Elevated baseline carcinoembryonic antigen (CEA) level, splenectomy at index CRS/HIPEC, and adjuvant chemotherapy utilization were statistically significant with conversion. Conversion had no impact on specific cytoreductive scores at repeat CRS/HIPEC (p = 0.435). Evaluating the effect on OS from the index CRS/HIPEC conversion had no impact. Mean OS was 9.5 and 8.8 years for cases that remained low-grade compared with those that converted, respectively (p = 0.668); however, when comparing OS from the time of conversion at repeat CRS/HIPEC, patients who progressed to high-grade disease had decreased survival at 4.4 versus 5.8 years (p = 0.0317). There was no difference in DFS between non-converters and converters at 4.1 and 3.6 years, respectively (p = 0.671).Conversion had no impact on OS from the index CRS/HIPEC but resulted in inferior survival from repeat surgery. Conversion was insignificant in regard to DFS, and should not be considered a contraindication to repeat CRS/HIPEC. Adjuvant chemotherapy should be avoided.

Neoadjuvant chemotherapy (NAT) is frequently utilized before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) for high-grade appendiceal neoplasms. The proposed benefits of NAT do not correlate with the limited literature.Retrospective review of our CRS-HIPEC registry. Primary outcomes were the effect of NAT on disease burden, cytoreduction scores, overall survival (OS), disease-free survival (DFS), and recurrence patterns.A total of 126 cases of high-grade disease met selection criteria; 73 cases received NAT before referral, and 53 cases received no therapy before referral and went directly to CRS-HIPEC. For those cases who received NAT 89% received a FOLFOX-based regimen. Mean PCI scores were 16.47 and 16.07 (P = 0.843) with complete cytoreductions rates of 79.5% and 75% (P = 0.556) for NAT and non-NAT cases, respectively. NAT cases were associated with significantly decreased OS and DFS rates. Mean OS was 3.6 and 2.5 years (P = 0.005) with actual 5-year OS rates of 24.2% versus 5% (P = 0.017) for non-NAT and NAT cases respectively. Mean DFS was 2.8 and 1.7 years (P = 0.015) with actual 5-year DFS rates of 18.6% versus 5.7% (P = 0.048) for non-NAT and NAT cases respectively. Lastly, the use of NAT had no impact on recurrence patterns (P = 0.221).This is the largest study to evaluate high-grade appendiceal neoplasms in regard to CRS-HIPEC and NAT. NAT had no impact in regard to disease burden, cytoreduction, or recurrence patterns. Utilization of NAT was associated with decreased OS and DFS.

The sartorius muscle transposition flap is the traditional method of femoral vessel coverage after superficial inguinal lymphadenectomy for regionally-metastatic cancers to the inguinal lymph nodes. However, if the groin has undergone radiotherapy, the sartorius muscle is contained within the irradiated field, and may be problematic for wound healing, in addition to being thin at its insertion and intimately related to several nerves. The gracilis muscle has been used for soft tissue defects and vascular graft infections, but its utility as an alternative to the sartorius muscle flap in the setting of radiation has never been reported. Here, we report the successful use of the retroflexed gracilis muscle flap for femoral vessel coverage after superficial inguinal lymphadenectomy, in a patient who previously underwent chemoradiation for locally-metastatic anal squamous cell carcinoma to the groin. An 86-year old female presented with Stage IIIB anal squamous cell carcinoma metastatic to one left inguinal lymph node. She underwent modified Nigro protocol chemoradiation treatment, which included radiation to the inguinal node basins. A left superficial inguinal lymphadenectomy was performed with a retroflexed gracilis muscle flap to cover the femoral vessels. This was chosen over a sartorius flap because the gracilis muscle was not located within the field of radiation. Despite a subsequent groin wound infection, the gracilis muscle flap remained viable and successfully protected the major vessels. We report the gracilis muscle flap as a viable alternative to the sartorius transposition muscle flap for femoral vessel coverage after oncologic superficial inguinal lymphadenectomy in the irradiated groin.

Background: The sartorius muscle transposition flap is the traditional method of femoral vessel tissue coverage after superficial inguinal lymphadenectomy for regionally-metastatic cancers to the inguinal lymph nodes. Well-vascularized muscle is the best material to cover vessels. However, if the groin has undergone radiation therapy, the sartorius muscle is contained within the irradiated field, and may be problematic for wound healing, in addition to being thin and tendinous at its insertion and intimately related to several nerves. The gracilis muscle, which is a thick well-vascularized muscle, has been used for soft tissue defects and vascular graft infections, but its utility as an alternative to the sartorius muscle flap in the setting of radiation has never been reported. Here, we report the successful use of the retroflexed gracilis muscle flap for femoral vessel coverage after superficial inguinal lymphadenectomy, in a patient who previously underwent chemoradiation for locally-metastatic anal squamous cell carcinoma to the groin. Case Presentation: An 86-year old female presented with Stage IIIB anal squamous cell carcinoma metastatic to one left inguinal lymph node (T2N2M0). She underwent modified Nigro protocol chemoradiation treatment, which included radiation to bilateral inguinal node basins and subsequent boost radiation to the left side. A left superficial inguinal lymphadenectomy was performed with a retroflexed gracilis muscle flap to cover the femoral vessels. This was chosen over a sartorius flap because the gracilis muscle was not located within the field of radiation and was more robust to fill the defect. The patient developed a groin wound infection, and the gracilis muscle flap remained viable and successfully protected the major vessels. Conclusions: We report the gracilis muscle flap as a viable alternative to the sartorius transposition muscle flap for femoral vessel coverage after oncologic superficial inguinal lymphadenectomy in the irradiated groin.

Lung regeneration occurs in a variety of adult mammals after surgical removal of one lung (pneumonectomy). Previous studies of murine post-pneumonectomy lung growth have identified regenerative “hotspots” in subpleural alveolar ducts; however, the cell-types participating in this process remain unclear. To identify the single cells participating in post-pneumonectomy lung growth, we used laser microdissection, enzymatic digestion and microfluidic isolation. Single-cell transcriptional analysis of the murine alveolar duct cells was performed using the C1 integrated fluidic circuit (Fluidigm) and a custom PCR panel designed for lung growth and repair genes. The multi-dimensional data set was analyzed using visualization software based on the tSNE algorithm. The analysis identified 6 cell clusters; 1 cell cluster was present only after pneumonectomy. This post-pneumonectomy cluster was significantly less transcriptionally active than 3 other clusters and may represent a transitional cell population. A provisional cluster identity for 4 of the 6 cell clusters was obtained by embedding bulk transcriptional data into the tSNE analysis. The transcriptional pattern of the 6 clusters was further analyzed for genes associated with lung repair, matrix production, and angiogenesis. The data demonstrated that multiple cell-types (clusters) transcribed genes linked to these basic functions. We conclude that the coordinated gene expression across multiple cell clusters is likely a response to a shared regenerative microenvironment within the subpleural alveolar ducts.

Pulmonary "air leaks," typically the result of pleural injury caused by lung surgery or chest trauma, result in the accumulation of air in the pleural space (pneumothorax). Air leaks are a major source of morbidity and prolonged hospitalization after pulmonary surgery. Previous work has demonstrated structural heteropolysaccharide (pectin) binding to the mouse pleural glycocalyx. The similar lectin-binding characteristics and ultrastructural features of the human and mouse pleural glycocalyx suggested the potential application of these polymers in humans. To investigate the utility of pectin-based polymers, we developed a simulacrum using freshly obtained human pleura. Pressure-decay leak testing was performed with an inflation maneuver that involved a 3 s ramp to a 3 s plateau pressure; the inflation was completely abrogated after needle perforation of the pleura. Using nonbiologic materials, pressure-decay leak testing demonstrated an exponential decay with a plateau phase in materials with a Young's modulus less than 5. In human pleural testing, the simulacrum was used to test the sealant function of four mixtures of pectin-based polymers. A 50% high-methoxyl pectin and 50% carboxymethylcellulose mixture demonstrated no sealant failures at transpleural pressures of 60 cmH2 O. In contrast, pectin mixtures containing 50% low-methoxyl pectin, 50% amidated low-methoxyl pectins, or 100% carboxymethylcellulose demonstrated frequent sealant failures at transpleural pressures of 40-50 cmH2 O (p

In the normal lung, a dominant structural element is an elastic "line element" that originates in the central bronchi and inserts into the distal airspaces. Despite its structural importance, the process that leads to development of the cable line element is unknown. To investigate the morphologic events contributing to its development, we used optical clearing methods to examine the postnatal rat lung. An unexpected finding was numerous spheres, with a median diameter of 1-2 µm, within the primary septa of the rat lung. The spheres demonstrated green autofluorescence, selective fluorescent eosin staining, reactivity with carboxyfluorescein succinimidyl ester, and specific labeling with anti-tropoelastin monoclonal antibody-findings consistent with tropoelastin. The sphere number peaked on rat postnatal day 4 (P4) and were rare by P14. The disappearance of the spheres was coincident with the development of the cable line element in the rat lung. Transmission electron microscopy demonstrated no consistent association between parenchymal cells and sphere alignment. In contrast, the alignment of tropoelastin spheres appeared to be the direct result of interactions of scaffold proteins including collagen fibers and fibrillin microfibrils. We conclude that the spatial organization of the cable line element appears to be independent of tropoelastin deposition, but dependent on crosslinking to scaffold proteins within the primary septa. Anat Rec, 300:1670-1679, 2017. © 2017 Wiley Periodicals, Inc.

Nintedanib, a tyrosine kinase inhibitor approved for the treatment of idiopathic pulmonary fibrosis, has anti-fibrotic, anti-inflammatory, and anti-angiogenic activity. We explored the impact of nintedanib on microvascular architecture in a pulmonary fibrosis model. Lung fibrosis was induced in C57Bl/6 mice by intratracheal bleomycin (0.5 mg/kg). Nintedanib was started after the onset of lung pathology (50 mg/kg twice daily, orally). Micro-computed tomography was performed via volumetric assessment. Static lung compliance and forced vital capacity were determined by invasive measurements. Mice were subjected to bronchoalveolar lavage and histologic analyses, or perfused with a casting resin. Microvascular corrosion casts were imaged by scanning electron microscopy and synchrotron radiation tomographic microscopy, and quantified morphometrically. Bleomycin administration resulted in a significant increase in higher-density areas in the lungs detected by micro-computed tomography, which was significantly attenuated by nintedanib. Nintedanib significantly reduced lung fibrosis and vascular proliferation, normalized the distorted microvascular architecture, and was associated with a trend toward improvement in lung function and inflammation. Nintedanib resulted in a prominent improvement in pulmonary microvascular architecture, which outperformed the effect of nintedanib on lung function and inflammation. These findings uncover a potential new mode of action of nintedanib that may contribute to its efficacy in idiopathic pulmonary fibrosis.

In many mammals, including humans, removal of one lung (pneumonectomy) results in the compensatory growth of the remaining lung. Compensatory growth involves not only an increase in lung size, but also an increase in the number of alveoli in the peripheral lung; however, the process of compensatory neoalveolarization remains poorly understood. Here, we show that the expression of α-smooth muscle actin (SMA)—a cytoplasmic protein characteristic of myofibroblasts—is induced in the pleura following pneumonectomy. SMA induction appears to be dependent on pleural deformation (stretch) as induction is prevented by plombage or phrenic nerve transection (P < 0.001). Within 3 days of pneumonectomy, the frequency of SMA⁺ cells in subpleural alveolar ducts was significantly increased (P < 0.01). To determine the functional activity of these SMA⁺ cells, we isolated regenerating alveolar ducts by laser microdissection and analyzed individual cells using microfluidic single-cell quantitative PCR. Single cells expressing the SMA (Acta2) gene demonstrated significantly greater transcriptional activity than endothelial cells or other discrete cell populations in the alveolar duct (P < 0.05). The transcriptional activity of the Acta2⁺ cells, including expression of TGF signaling as well as repair-related genes, suggests that these myofibroblast-like cells contribute to compensatory lung growth. Keywords: compensatory growth; gene expression; lung; myofibroblasts, National Institutes of Health (U.S.) (Grant HL94567), National Institutes of Health (U.S.) (Grant CA009535), National Institutes of Health (U.S.) (Grant ES000002)

Objectives: The mesothelium, the surface layer of the heart, lung, bowel, liver and tunica vaginalis, is a complex tissue implicated in organ-specific diseases and regenerative biology; however, the mechanism of mesothelial repair after surgical injury is unknown. Previous observations indicated seeding of denuded mesothelium by free-floating mesothelial cells may contribute to mesothelial healing. In this study, we investigated the prevalence of mesothelial cells in pleural fluid during the 7 days following pulmonary surgery. Study design: Flow cytometry was employed to study pleural fluid of 45 patients after lung resection or transplantation. We used histologically validated mesothelial markers (CD71 and WT1) to estimate the prevalence of mesothelial cells. Results: The viability of pleural fluid cells approached 100%. Leukocytes and mesothelial cells were identified in the pleural fluid within the first week after surgery. The leukocyte concentration was relatively stable at all time points. In contrast, mesothelial cells, identified by CD71 and WT1 peaked on POD3. The broad expression of CD71 molecule in postoperative pleural fluid suggests that many of the free-floating non-leukocyte cells were activated or proliferative mesothelial cells. Conclusion: We demonstrated that pleural fluid post lung surgery is a source of mesothelial cells; most of these cells appear to be viable and, as shown by CD71 staining, activated mesothelial cells. The observed peak of mesothelial cells on POD3 is consistent with a potential reparative role of free-floating mesothelial cells after pulmonary surgery.

Bioadhesives are biopolymers with potential applications in wound healing, drug delivery, and tissue engineering. Pectin, a plant-based heteropolysaccharide, has recently demonstrated potential as a mucoadhesive in the gut. Since mucoadhesion is a process likely involving the interpenetration of the pectin polymer with mucin chains, we hypothesized that pectin may also be effective at targeting the glycocalyx of the visceral mesothelium. To explore the potential role of pectin as a mesothelial bioadhesive, we studied the interaction of various pectin formulations with the mesothelium of the lung, liver, bowel, and heart. Tensile strength, peel strength, and shear resistance of the bioadhesive-mesothelial interaction were measured by load/displacement measurements. In both high-methoxyl pectins (HMP) and low-methoxyl pectins, bioadhesion was greatest with an equal weight % formulation with carboxymethylcellulose (CMC). The tensile strength of the high-methoxyl pectin was consistently greater than low-methoxyl or amidated low-methoxyl formulations (p

Pulmonary “air leaks,” typically the result of pleural injury caused by lung surgery or chest trauma, result in the accumulation of air in the pleural space (pneumothorax). Air leaks are a major source of morbidity and prolonged hospitalization after pulmonary surgery. Previous work has demonstrated structural heteropolysaccharide (pectin) binding to the mouse pleural glycocalyx. The similar lectin-binding characteristics and ultrastructural features of the human and mouse pleural glycocalyx suggested the potential application of these polymers in humans. To investigate the utility of pectin-based, we developed a simulacrum using freshly obtained human pleura. Pressure-decay leak testing was performed with an inflation maneuver that involved a 3 second ramp to a 3 second plateau pressure; the inflation as completely abrogated after needle perforation of the pleura. Using non-biologic materials, pressure-decay leak testing demonstrated an exponential decay with a plateau phase in materials with a Young’s modulus less than 5. In human pleural testing, the simulacrum was used to test the sealant function of four mixtures of pectin-based polymers. A 50% high-methoxyl pectin and 50% carboxymethylcellulose mixture demonstrated no sealant failures at transpleural pressures of 60 cm H(2)0. In contrast, pectin mixtures containing 50% low-methoxyl pectin, 50% amidated low-methoxyl pectins, or 100% carboxymethylcellulose demonstrated frequent sealant failures at transpleural pressures of 40–50 cm H(2)O (p

The axial connective tissue system is a fiber continuum of the lung that maintains alveolar surface area during changes in lung volume. Although the molecular anatomy of the axial system remains undefined, the fiber continuum of the lung is central to contemporary models of lung micromechanics and alveolar regeneration. To provide a detailed molecular structure of the axial connective tissue system, we examined the extracellular matrix of murine lungs. The lungs were decellularized using a 24 hr detergent treatment protocol. Systematic evaluation of the decellularized lungs demonstrated no residual cellular debris; morphometry demonstrated a mean 39 ± 7% reduction in lung dimensions. Scanning electron microscopy (SEM) demonstrated an intact structural hierarchy within the decellularized lung. Light, fluorescence, and SEM of precision-cut lung slices demonstrated that alveolar duct structure was defined by a cable line element encased in basement membrane. The cable line element arose in the distal airways, passed through septal tips and inserted into neighboring blood vessels and visceral pleura. The ropelike appearance, collagenase resistance and anti-elastin immunostaining indicated that the cable was an elastin macromolecule. Our results indicate that the helical line element of the axial connective tissue system is composed of an elastin cable that not only defines the structure of the alveolar duct, but also integrates the axial connective tissue system into visceral pleura and peripheral blood vessels.