Pericardial Adipose Tissue Thrombospondin-1 Associates With Antiangiogenesis in Ischemic Heart Disease

Accumulation of ectopic pericardial adipose tissue has been associated with cardiovascular complications which, in part, may relate to adipose-derived factors that regulate vascular responses and angiogenesis. We sought to characterize adipose tissue microvascular angiogenic capacity in subjects who underwent elective cardiac surgeries including aortic, valvular, and coronary artery bypass grafting. Pericardial adipose tissue was collected intraoperatively and examined for angiogenic capacity. Capillary sprouting was significantly blunted (twofold, p <0.001) in subjects with coronary artery disease (CAD) (age 60 ± 9 years, body mass index [BMI] 32 ± 4 kg/m2, low-density lipoprotein cholesterol [LDL-C] 95 ± 46 mg/100 ml, n = 29) compared with age-, BMI-, and LDL-C matched subjects without angiographic obstructive CAD (age 59 ± 10 y, BMI 35 ± 9 kg/m2, LDL-C 101 ± 40 mg/100 ml, n = 12). For potential mechanistic insight, we performed mRNA expression analyses using quantitative real-time polymerase chain reaction and observed no significant differences in pericardial fat gene expression of proangiogenic mediators vascular endothelial growth factor-A (VEGF-A), fibroblast growth factor-2 (FGF-2), and angiopoietin-1 (angpt1), or anti-angiogenic factors soluble fms-like tyrosine kinase-1 (sFlt-1) and endostatin. In contrast, mRNA expression of anti-angiogenic thrombospondin-1 (TSP-1) was significantly upregulated (twofold, p = 0.008) in CAD compared with non-CAD subjects, which was confirmed by protein western-immunoblot analysis. TSP-1 gene knockdown using short hairpin RNA lentiviral delivery significantly improved angiogenic deficiency in CAD (p <0.05). In conclusion, pericardial fat in subjects with CAD may be associated with an antiangiogenic profile linked to functional defects in vascularization capacity. Local paracrine actions of TSP-1 in adipose depots surrounding the heart may play a role in mechanisms of ischemic heart disease.

Novel method for bronchial stump coverage for prevents postpneumonectomy bronchopleural fistula: pedicled thymopericardial fat flap

Background

Bronchopleural fistula (BPF) is a serious complication with high mortality and morbidity that can be seen after lung resections. Although several methods have been described to prevent postoperative BPF it is still unclear which method is the best. In this study, we have used tymopericardial fat flap (TPFF) to cover the bronchial stump in patients after pneumonectomy and aim to show its feasibility and efficacy to prevent BPF.

Methods

Between January 2013 and June 2021, 187 patients with lung cancer underwent pneumonectomy at our institution. Among them, 53 patients underwent bronchial stump coverage with TPFF. In other 134 patients there wasn’t used any coverage method. Patient characteristics, preoperative status, surgical procedures, perioperative course, pathological findings, and long-term prognoses were evaluated retrospectively.

Results

Postoperative BPF was observed in 16 (%8.5) patients. It was observed that TPFF was applied in only 1 of the patients who developed BPF. A statistically significant difference was detected between TPFF-coverage with non-coverage groups in terms of postoperative BPF rates (p = 0.044). Other factors associated with the development of postoperative BPF in univariate analysis were right sided pneumonectomy, and re-operation.

Conclusion

Bronchial stump coverage with TPFF is a feasible and effective method to prevent postpneumonectomy BPF.

Intraoperative methods for wrapping anastomoses after airway reconstruction: a case series

Background

Anastomosis management is the main challenge of airway resection and reconstruction, and postoperative anastomotic complications, including ischemia, stenosis, dehiscence, and separation may lead to severe outcomes and a poor prognosis. The anastomotic buttress is vital in airway reconstruction, but the selection of surgical buttress and reinforcement remains controversial. We aimed to demonstrate and evaluate the buttress options of anastomosis, including their preoperative characteristics, the intraoperative process, and the incidence of postoperative complications to help address the controversy regarding anastomosis management.

Methods

This retrospective study was conducted at a single institution. Patients who underwent airway reconstruction with anastomotic wrapping from Jan. 2019 to Sep. 2021 were enrolled in this study and preoperative characteristics and operational features were collected. All patients were carefully followed up by telephone and outpatient. Their postoperative complications and postoperative status after 6 months were recorded. The surgical procedures and clinical characteristics of the buttress options of anastomosis were assessed.

Results

A total of 62 patients undergoing either cervical tracheal, thoracic tracheal, carinal, or secondary carinal and main bronchus resection and reconstruction were evaluated. The anastomotic buttress used included mediastinal pleural flap (24/62, 38.7%), anterior cervical muscle (14/62, 22.6%), sternocleidomastoid (2/62, 3.2%), thymus flap (12/62, 19.4%), intercostal muscle flap (2/62, 3.2%), biological patch (2/62, 3.2%), prepericardial fat (1/62, 1.6%), thyroid gland (1/62, 1.6%), pectoralis major flap (2/62, 3.2%), and omental flap (2/62, 3.2%). All procedures produced satisfactory results without short-term anastomotic complications. A follow-up for 6 months was conducted and all patients were alive postoperatively. Tracheomalacia stenosis postoperatively occurred in 3 patients and they were subsequently treated with an endotracheal stent. One patient had tumor recurrence 3 months after surgery and received adjuvant chemotherapy.

Conclusions

Various anastomotic wrapping materials are used in airway reconstruction. Different utilizations of buttress are selected according to the anatomic characteristics and the reconstruction method used. This study indicated that appropriate surgical buttresses for wrapping anastomoses are legitimate alternatives to reduce the risk of anastomotic complications.

Autologous Multilayered Fibroblast Sheets Can Reinforce Bronchial Stump in a Rat Model

Bronchopleural fistula is one of the most serious postoperative complications caused by the incomplete healing of a bronchial stump. Fibroblasts play an important role in wound healing by facilitating connective tissue formation and inducing angiogenesis. We developed a method for production of multilayered fibroblast sheets that secreted some growth factors and promoted wound healing. The present study aimed to assess the treatment effect of multilayered fibroblast sheets on bronchial stump healing. In this rat model, left pneumonectomy was performed, and multilayered fibroblast sheets derived from autologous oral mucosal tissues were transplanted to the bronchial stump. The changes in the bronchial stump were examined macroscopically, histologically, and mechanically. The fibroblast sheets promoted the formation of thick connective tissues around the bronchial stump. The formed connective tissues were accompanied by new blood vessels, and fibrosis was observed over time. Then, 7 days after the transplantation of the fibroblast sheets, the bronchial wall became significantly thicker, and the area of the blood vessels for the bronchial wall tissues was significantly larger in the experimental group than in the control group. In addition, the burst pressure in the bronchial stump was significantly higher in the experimental group than in the control group. Bronchial stumps were reinforced by the transplantation of multilayered fibroblast sheets derived from autologous oral mucosal tissues.

Prophylaxis and management of postoperative complications after tracheobronchial surgery

Prevention of bronchial complications after airway surgery must be our primary goal. Understanding bronchial and anastomotic healing is the first step to success. This can be improved by standardizing operating technique (bronchial closure and end-to-end anastomosis) as well as postoperative care. Bronchopleural fistula after pneumonectomy still remains a feared complication with a high mortality rate. Especially after sleeve resection interpretation of endobronchial healing and postoperative measures of care with the help of an algorithm, may avoid anastomotic insufficiency and therefore reduced the secondary pneumonectomy rate.

Indocyanine green fluorescence/thermography evaluation of intercostal muscle flap vascularization

Background

During anatomical lung resection in high‐risk patients, the bronchial stump is covered with tissue flaps (e.g. pericardial fat tissue and intercostal muscle) to prevent bronchopleural fistula development. This is vital for reliable reinforcement of the bronchial stump. We evaluated the blood supply of the flap using indocyanine green fluorescence (ICG‐FL) and thermography intraoperatively in 27 patients at high risk for developing a bronchopleural fistula.

Methods

Before reinforcing the stump with a flap, the fluorescence agent was intravenously injected and the blood supply was evaluated. The surface temperature of the flap was measured with thermography. The two modalities were then compared.

Results

ICG‐FL intensity and surface temperature on the distal compared to the proximal side of the flap decreased by 32.6 ± 29.4% (P < 0.0001) and 3.5 ± 2.0°C (P < 0.0001), respectively. In patients with a higher ICG‐FL intensity value at the tip than the median, the surface temperature at the tip decreased by 2.7 ± 1.7°C compared to the proximal side. In patients with a lower ICG‐FL value at the tip, the surface temperature decreased by 4.6 ± 1.7°C (P = 0.0574). The bronchial stump reinforced the part of the flap with adequate blood supply; none of the patients developed a bronchopleural fistula.

Conclusions

ICG‐FL confirmed variation in the blood supply of the intercostal muscle flap, even if prepared using the same surgical procedure. Thermography analysis tends to correlate with the fluorescence method, but may be influenced by the state of flap preservation during surgery.

The experimental validation of free fat grafts in thoracic surgery

We evaluated the viability of free fat grafts in the thoracic cavity using 3-month old male swine (n = 2). After left caudal lobectomy, 1-3 g of subcutaneous fat tissue harvested via the thoracotomy site was implanted in the chest cavity. At re-thoracotomy 6 weeks after implantation, all of the implanted fat grafts (n = 15) were found to have closely adhered to the parietal pleura and visceral pleura. There was a significant decrease by ∼30% in the weight of the fat grafts after implantation. Regardless of the weight loss, the implanted fat graft showed normal structuring without scar formation in the central area. Our results may suggest that free fat pads, which weighed up to 3 g, were successfully cultured in the thoracic cavity until the implanted tissues integrated into the surrounding tissues. Therefore, the free fat pad can be used as a biomaterial for some purposes in thoracic surgery.