[Preliminary outcomes of neoadjuvant chemoimmunotherapy combined with transoral robotic surgery for locally advanced oropharyngeal squamous cell carcinoma].

Objective: To evaluate the efficacy of neoadjuvant chemoimmunotherapy (NACI) combined with transoral robotic surgery (TORS) in the treatment of locally advanced oropharyngeal squamous cell carcinoma (OPSCC). Methods: This was a retrospective study of 15 patients with locally advanced OPSCC who underwent TORS after neoadjuvant therapy (NAT) at the Department of Otolaryngology-Head and Neck Surgery of Sun Yat-sen Memorial Hospital of Sun Yat-sen University from April 2019 to February 2023. There were 12 males and 3 females, aged 31 to 74 years. Twelve cases were tonsil cancer, and 3 cases were tongue base cancer. There were 11 cases in stage Ⅲ and 4 cases in stage Ⅳ. Two patients received neoadjuvant chemotherapy and 13 patients received NACI, with 2 to 3 cycles, and all patients underwent TORS after multidisciplinary team consultation. The clinicopathological characteristics, surgical outcomes, and oncological results were summarized. Results: All surgeries were successfully completed with negative surgical margins, and no case was required conversion surgery. All patients were fed via nasogastric tubes postoperatively, with a median gastric tube stay of 7 days (range: 2-60 days). No tracheotomy was applied. There were no major complications such as postoperative bleeding. Pathological complete response (pCR) was found in 10 cases (76.9%) among the 13 patients with NACI. The follow-up time was 21 months (range: 10-47 months), and there was no death or distant metastasis. One patient with rT0N3M0 tonsil cancer had local recurrence 5 months after surgery. The 2-year overall survival and 2-year disease-free survival were respectively 100.0% and 93.3% in the 15 patients. Conclusion: NACI combined with TORS provides a safe, effective and minimally invasive treatment for patients with locally advanced oropharyngeal squamous cell carcinoma.

[Preliminary experience of gasless transoral vestibular robotic thyroidectomy].

Objective: To explore the feasibility and safety of the gasless transoral vestibular robotic thyroidectomy using skin suspension. Methods: The clinical data of 20 patients underwent gasless transoral vestibular robotic thyroidectomy in the Department of Otorhinolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University from February 2022 to May 2022 were retrospectively analyzed. Among them, 18 were females and 2 were males, aged (38.7±8.0) years old. The intraoperative blood loss, operation time, postoperative hospital stay, postoperative drainage volume, postoperative pain visual analogue scale (VAS) score, postoperative swallowing function swallowing impairment score-6 (SIS-6), postoperative aesthetic VAS score, postoperative voice handicap index-10 (VHI-10) voice quality, postoperative pathology and complications were recorded. SPSS 25.0 was used for statistical analysis of the data. Results: The operations were successfully completed without conversion to open surgery in all patients. Pathological examination showed papillary thyroid carcinoma in 18 cases, retrosternal nodular goiter in 1 case, and cystic change in goiter in 1 case. The operative time for thyroid cancer was 161.50 (152.75, 182.50) min [M (P25, P75), the same below] and the average operative time for benign thyroid diseases was 166.50 minutes. The intraoperative blood loss 25.00 (21.25, 30.00) ml. In 18 cases of thyroid cancer, the mean diameter of the tumors was (7.22±2.02) mm, and lymph nodes (6.56±2.14) were dissected in the central region, with a lymph node metastasis rate of 61.11%. The postoperative pain VAS score was 3.00 (2.25, 4.00) points at 24 hours, the mean postoperative drainage volume was (118.35±24.32) ml, the postoperative hospital stay was 3.00 (3.00, 3.75) days, the postoperative SIS-6 score was (4.90±1.58) points at 3 months, and the postoperative VHI-10 score was 7.50 (2.00, 11.00) points at 3 months. Seven patients had mild mandibular numbness, 10 patients had mild cervical numbness, and 3 patients had temporary hypothyroidism three months after surgery and 1 patient had skin flap burn, but recovered one month after surgery. All patients were satisfied with the postoperative aesthetic effects, and the postoperative aesthetic VAS score was 10.00 (10.00, 10.00). Conclusion: Gasless transoral vestibular robotic thyroidectomy using skin suspension is a safe and feasible option with good postoperative aesthetic effect, which can provide a new treatment option for some selected patients with thyroid tumors.

[Preliminary experience of robotic lateral neck dissection via combined axillary-retroauricular approach for N1b papillary thyroid carcinoma].

Objective: To evaluate the feasibility, safety, and short-term efficacy of robotic lateral neck dissection via combined axillary-retroauricular approach for N1b papillary thyroid carcinoma (PTC). Methods: Thirty patients with cT1-2N1bM0 PTC who received robotic lateral neck dissection via combined axillary-retroauricular approach were included in the Department of Otorhinolaryngology of Sun Yat-sen Memorial Hospital from December 2016 to December 2020. There were 10 males and 20 females, with a median age of 34.5 years and a median body mass index of 25.55 kg/m2. The clinical, surgical, complications, pathology and follow-up data were analysed with SPSS 25.0 software package. Results: The median operative time of 30 patients was 255.50 min, the median operative blood loss was 69.00 ml, and the median postoperative hospital stay was 6.00 days. The incidence of postoperative temporary recurrent laryngeal nerve paralysis was 3.33% (1/30), temporary hypoparathyroidism was 16.67%(5/30), temporary accessory nerve injury was 3.33% (1/30), hematoma was 3.33% (1/30) and chylous leakage was 3.33% (1/30). The median visual analogue scale (VAS) score was 8.00, and the follow-up time was 13-38 months, with a median of 25.5 months. One case showed cervical lymph node recurrence 14 months after surgery. The most recent dynamic recurrence risk stratification showed 21 patients (70.00%) had excellent responses. Conclusions: Robotic lateral neck dissection via combined axillary-retroauricular approach for unilateral cN1b PTC is safe, feasible and aesthetic. The short-term efficacy and dynamic recurrence risk stratification results of short-term follow-up are satisfactory. It can provide a surgical option for cN1b PTC patients.

Correction to: CCN2 inhibits lung cancer metastasis through promoting DAPK-dependent anoikis and inducing EGFR degradation.

Following publication of their article "CCN2 inhibits lung cancer metastasis through promoting DAPK-dependent anoikis and inducing EGFR degradation", the authors reported an error in Fig.6b. α-Tubulin image of rCCN2 treatment  (upper panel in CL1-5) only showed eight lanes, when there should be nine.

[Robotic nasopharyngectomy via combined approach of nose and oral for local recurrent nasopharyngeal carcinoma].

Objective:Surgery is one of the salvage treatments for recurrent nasopharyngeal carcinoma. The safety and efficacy of Da Vinci's robotic surgery was preliminarily investigated to resect recurrent nasopharyngeal cancer after one-course radiotherapy.Method:Since Oct 2017, Da Vinci surgery system was used to complete the operation of locally recurrent nasopharyngeal carcinoma including two approaches, such as trans oral with soft palate incision and trans oral and nose with soft palate suspended.Result:Ten patients underwent robotic nasopharyngectomy, The median operation time was 90 minutes, median follow-up time was 6 months, and all patients had clear resection margins. There was no residual, recurrent or cancer related death during short-term follow-up.Conclusion:Robotic nasopharyngectomy via combined approach of nose and mouth is safe, effective and has good local control.

[Robot-assisted transaxillary thyroidectomy: our early experience].

Objective:To evaluate the feasibility, effectiveness and safety of robot-assisted transaxillary thyroidectomy (RATT).Method: The clinical data of 66 patients undergoing RATT from November 2016 to May 2018 were prospectively collected and analyzed. The average age was (38.61±11.72) years, 57 cases were female and 9 cases were male. Preoperative fine needle aspiration biopsy revealed papillary thyroid carcinoma in 58 cases and follicular thyroid tumor in 8 cases.Result:All the patients successfully completed RATT, and there was no open operation, in which 54 cases of ipsilateral lobetomy and isthmus resection and ipsilateral central lymph node dissection, 8 cases with ipsilateral lobectomy and contralateral near-total lobectomy, and total thyroidectomy with ipsilateral central lymph node dissection and selective neck dissection combined with retroauricular approach in 4 cases. The mean operative time was (124.30±23.41) min, and the average bleeding volume was (17.73±8.28) ml. The mean diameter of thyroid papillary carcinoma was (0.71±6.22) cm, and the postoperative drainage volume was (67.57±25.11) ml. The average postoperative hospitalization time was (3.24±0.81) days. 3 cases (4.5%) had temporary laryngeal nerve palsy after operation, and 1 case (1.5%) had temporary hypocalcemia after operation, all recovered after one month. No postoperative bleeding, subcutaneous emphysema, drinking water cough and permanent hypocalcemia were observed. The average numbers of lymph node dissection in PTC patients were (6.26±4.76), of which 21 cases (36.2%) had lymph node metastasis, postoperative stage T1 54 cases, T2 4 cases, N1a 17 cases, N1b 4 cases. The follow-up time were 1-18 months. The postoperative cosmetic VAS score in January was (9.66±0.54). Ultrasound showed no residual glands in the affected thyroid gland, and there was no recurrence in the local and regional regions.Conclusion:RATT is safe and feasible with good aesthetic effect and can be used as an option for the treatment of thyroid diseases..

Suppressed CCL2 expression inhibits the proliferation of leukemia cells via the cell cycle protein Cyclin D1: preliminary in vitro data.

OBJECTIVE: Chemokine (C-C motif) ligand 2 (CCL2) is a member of the CC subfamily, which displays chemotactic activity for monocytes and basophils. This molecule plays a very important role in many solid tumors and shows changes in the bone marrow microenvironment. However, its role in acute myeloid leukaemia (AML) is still unclear. MATERIALS AND METHODS: In this study, we established a HL-60 cell line with CCL2 knockdown to explore its effect on leukemogenesis. Lentivirus with CCL2-knockdown was successfully constructed after screening effective CCL2 short hairpin RNA (shRNA) sequences and was transfected into HL-60 cells, which was further validated at the mRNA and protein levels by real-time polymerase chain reaction (PCR) and Western blotting, respectively. RESULTS: Low expression of CCL2 significantly decreased HL-60 cell growth by increasing the cell arrest at G1 phase by 12% more than controls. We applied RNA sequencing technology to discriminate the gene expression profiles between the cells with CCL2 knockdown and the controls, and Cyclin D1 was selected for further experiments as its expression level was significantly downregulated, which was validated at the mRNA and protein levels. Cyclin D1 knockdown experiments showed that the cell proliferation rate was evidently decelerated, and cell cycle analysis also indicated a similar pattern for CCL2. CONCLUSIONS: Our study revealed that Cyclin D1 is an effector that mediates CCL2's function in cell proliferation by blocking cells at G1 phase.

[Gasless endoscopic selective lateral neck dissection via an anterior chest approach for papillary thyroid carcinomas].

Objective: To assess the safety and curative effect of gasless endoscopic selective lateral neck dissection (GESLND) via an anterior chest approach for papillary thyroid carcinoma (PTC). Methods: Eighteen patients with PTC(T1-2N1bM0, size<3.0 cm), having GESLND via an anterior chest approach, were included from November 2008 to December 2016. Results: GESLND via an anterior chest approach was successfully performed in all 18 PTC patients (seven male and eleven female) with 83.3% of T1 and 16.7% of T2. The mean operative time of selective lateral neck dissection was 73 min (range 51-92 min). The mean of intraoperative bleeding was 61.1 ml (range 30-120 ml). No major complications occurred except one transient hypoparathyroidism. No residual thyroid glands were detected on ultrasonography and thyroglobulin was(0.73±0.16)ng/ml three months postoperatively. The median of follow-up was 54.5 months (range 6-104 months). No recurrence disease was observed in any patient on ultrasonography, computer tomography, thyroglobulin or selective iodine-131 scan during the follow-up period. The cosmetic result and functional preservation was excellent, when the assessments were performed three months postoperatively. Conclusion: GESLND via an anterior chest approach is feasible and safe for selected PTCs, with superior appearance.

KLHL39 suppresses colon cancer metastasis by blocking KLHL20-mediated PML and DAPK ubiquitination.

Cullin 3 (Cul3)-family ubiquitin ligases use the BTB-domain-containing proteins for the recruitment of substrates, but the regulation of this family of ubiquitin ligases has not been completely understood. KLHL20 is a BTB-family protein and targets tumor suppressor promyelocytic leukemia protein (PML) and death-associated protein kinase (DAPK) to its kelch-repeat domain for ubiquitination and degradation. Here, we show that another BTB-kelch protein KLHL39 is recruited to the substrate-binding domain of KLHL20 but is not a substrate of Cul3-KLHL20 complex. Interestingly, KLHL39 does not bind Cul3 because of the absence of certain conserved residues in the BTB domain. Instead, KLHL39 blocks KLHL20-mediated ubiquitination of PML and DAPK by disrupting the binding of these substrates to KLHL20 as well as the binding of KLHL20 to Cul3. Through the two mechanisms, KLHL39 increases the stability of PML and DAPK. In human colon cancers, downregulations of KLHL39, PML and DAPK are associated with metastatic progression. Furthermore, preclinical data indicate that KLHL39 promotes colon cancer migration, invasion and survival in vitro and metastasis in vivo through a PML- and DAPK-dependent mechanism. Our study identifies KLHL39 as a negative regulator of Cul3-KLHL20 ubiquitin ligase and reveals a role of KLHL39-mediated PML and DAPK stabilization in colon cancer metastasis.

CCN2 inhibits lung cancer metastasis through promoting DAPK-dependent anoikis and inducing EGFR degradation.

CCN family protein 2 (CCN2), also known as connective tissue growth factor, is a secreting protein that modulates multiple cellular events. We previously demonstrated the metastasis-suppressive effect of CCN2 in lung cancer cells. In this study, we investigate the role of CCN2 in anoikis, a form of programmed cell death that is critical in suppressing cancer metastasis. CCN2 binds to the epidermal growth factor receptor (EGFR) and triggers ubiquitination by inhibiting the formation of the ß-pix/Cbl complex, resulting in the degradation of EGFR. Binding of CCN2 to EGFR suppresses the phosphorylation of c-Src and extracellular signal-regulated kinase but increases the expression of death-associated protein kinase, which leads to anoikis. Overall, our findings provide evidence validating the use of CCN2 as an anti-metastatic therapy in lung cancer patients, and prospect a potential therapeutic synergy between CCN2 and the anti-EGFR antibody for the treatment of lung cancer.

Association of TNF-alpha gene polymorphisms with systemic lupus erythematosus in Taiwanese patients.

Tumour necrosis factor-alpha (TNF-alpha), an important proinflammatory cytokine, exerts a variety of physiological and pathogenic effects that lead to tissue destruction. Studies on the association of TNF-alpha genetic polymorphisms with systemic lupus erythematosus (SLE) have yielded inconclusive results. We investigated the association of TNF-alpha genetic polymorphisms (-1031T/C, -863C/A, -857T/C, -308A/G and +489A/G) with SLE in Taiwanese patients and controls. Our results indicate that 1) the frequency of the A-allele at -863 position was significantly higher in SLE patients (odds ratio = 1.46; 95% CI = 1.02-2.08); 2) the frequency of the A-allele at +489 position was significantly higher in SLE patients (odds ratio = 1.79; 95% CI = 1.21-2.65); 3) the AA or GA genotype frequencies at +489 position were significantly increased in SLE patients (AA genotype: odds ratio = 11.20; 95% CI = 1.36-92.55; GA genotype: odds ratio = 1.63; 95% CI = 1.03-2.58); 4) no significant association of TNF-alpha haplotypic distributions was observed, except for the haplotypes TCCGA, CACGA and CCCGG; and 5) the genotype frequency of the polymorphisms at -1031 was significantly different in patients with antinuclear antibodies (P = 0.022). The allele and genotype frequencies of the polymorphisms at -863 were not significantly different. The genotype frequency of the polymorphisms at -857 was significantly different in patients with haematological disorder (P = 0.025). The frequency of A allele of the polymorphisms at -308 was significantly increased in patients with malar rash (P = 0.033), discoid rash (P = 0.023), photosensitivity (P = 0.037), oral ulcers (P = 0.002) and serositis (P = 0.029). The genotype frequency of the polymorphisms at +489 was significantly different in patients with discoid rash and photosensitivity (data not shown; discoid rash, P = 0.031; photosensitivity, P = 0.044). These results suggest that TNF-alpha genetic polymorphisms contribute to SLE susceptibility in the Taiwanese population.

Lack of association between pro-inflammatory cytokine (IL-6, IL-8 and TNF-alpha) gene polymorphisms and Graves' disease.

Graves' disease (GD) is a common, autoimmune disease involving the thyroid gland, and it has been previously suggested that pro-inflammatory cytokines are involved in the disease's pathogenesis. The aim of this study was to test whether the interleukin (IL)-6 gene promoter region, or tumour necrosis factor (TNF)-alpha or IL-8 gene 3'-untranslated region (3'-UTR) polymorphisms could provide useful genetic markers for an individual's susceptibility to GD. A normal control group of 60 healthy people and 95 patients featuring GD were examined. Polymerase chain reaction (PCR)-based restriction analysis was performed for the three gene polymorphisms using endonucleases BsrBI, NcoI and ApaLI, respectively. We found no significant difference between the frequencies of genotype and allelic variants for the IL-6 gene promoter (-572 G/C), the TNF-alpha gene promoter (-308 A/G) and the IL-8 gene 3'-UTR (2767 A/G) for GD patients and for normal controls. Cytokines are a large group of proteins that may elicit multiple effects upon immunological reactions. It still appears to be very worthwhile to continue to aggressively search for cytokine gene polymorphisms in order to predict the development of such disease.

Role of breast tumour kinase in the in vitro differentiation of HaCaT cells.

BACKGROUND: Breast tumour kinase (BRK) is a newly identified non-receptor protein tyrosine kinase from a metastatic breast tumour. Its biological functions are still under extensive investigation. The mouse homologue Sik (Src-related intestinal kinase) has been implicated in mouse keratinocyte differentiation; however, not much is known about the functions of BRK in human cutaneous biology. OBJECTIVES: Using HaCaT cells as an experimental model, to explore the mutual relationships between BRK and differentiation of human keratinocytes. METHODS: Archival paraffin blocks of normal and pathological skin were retrieved for examining the in vivo distribution of BRK. Its expression and subcellular localization were examined via indirect immunofluorescence, and quantitative changes were analysed by Northern and Western blots. The kinase activity of BRK was determined by its autophosphorylation and phosphorylation of exogenous substrate in the in vitro kinase assay. Using a retroviral infection method, we established stably transfected HaCaT cells expressing vector, wild-type BRK or a kinase-defective mutant (K219M). Expression of the differentiation marker keratin 10 (K10) was compared among these cells using semiquantitative reverse transcription-polymerase chain reaction. Results Histochemical examination showed that BRK was expressed exclusively in suprabasal keratinocytes. Its distribution was both cytoplasmic and intranuclear. An enhanced regional suprabasal expression pattern was observed in the confluent areas of cell cultures. The expression of BRK transcript and protein was up-regulated in prolonged confluence culture in a serum-dependent manner. Its kinase activity was activated shortly after the addition of calcium and ionomycin and returned to the basal level within 30 min. Overexpression of wild-type BRK moderately promoted the expression of K10 transcript while the kinase-defective BRK mutant exerted a prominent suppressive effect. CONCLUSIONS: The in vivo distribution of BRK and its up-regulation during in vitro differentiation of HaCaT cells, together with the activation of its kinase activity by calcium/ionomycin and its influence on K10 expression, all indicate a role for BRK in the complex process of keratinocyte differentiation.

Automated distal coronary bypass with a novel magnetic coupler (MVP system).

OBJECTIVE: We sought to assess the feasibility of performing sutureless distal coronary artery bypass anastomoses with a novel magnetic coupling device. METHODS: From May 2000 to April 2001, single-vessel side-to-side coronary artery bypass grafting on a beating heart was performed in 39 domestic white pigs (35-60 kg) without the use of mechanical stabilization, shunts, or perfusion bridges. Animals were divided into 2 groups. Seventeen pigs underwent right internal thoracic artery to right coronary artery bypass grafting through a median sternotomy (group 1) with a novel magnetic vascular positioning system (MVP system; Ventrica, Inc, Fremont, Calif). Twenty-two pigs underwent left internal thoracic artery to left anterior descending artery grafting with the MVP anastomotic device through a left anterior minithoracotomy (group 2). This system consists of 2 pairs of elliptical magnetic implants and a deployment device. One pair of magnets forms the anastomotic docking port within the graft; the other pair forms an identical anastomotic docking port within the target vessel. The anastomosis is created when the 2 docking ports magnetically couple. Anastomotic patency was evaluated by means of angiography during the first postoperative week and at 1 month. Histologic studies were performed at different time points as late as 6 months. RESULTS: Right internal thoracic artery to right coronary artery anastomoses and left internal thoracic artery to left anterior descending artery anastomoses were successfully performed with the system in all animals. The self-adherent and self-aligning properties of the implants allowed for immediate and secure approximation of the arteries (total anastomotic time between 2-3 minutes). Anastomoses were constructed without a stabilization platform. Five nondevice-related deaths occurred postoperatively. One-week angiography, performed in 35 surviving animals, showed a patent graft and anastomosis in all cases. The patency rate at 1 month was 97% (33/34). Histologic studies as late as 6 months demonstrated neointimal coverage of the magnets without any significant luminal obstruction. Histology also confirmed the presence of viable tissue between magnets. CONCLUSION: The MVP anastomotic system uses magnetic force to create rapid and secure distal coronary artery anastomoses, which might facilitate minimally invasive and totally endoscopic coronary artery bypass surgery.

Does coronary artery bypass grafting alone correct moderate ischemic mitral regurgitation?

BACKGROUND: The optimal management of moderate (3+ on a scale of 0 to 4+) ischemic mitral regurgitation (MR) remains controversial. Some advocate CABG alone, whereas others favor concomitant mitral annuloplasty. To clarify the optimal management of these patients, we evaluated the early impact of isolated CABG on moderate ischemic MR. METHODS AND RESULTS: Between January 1992 and August 1999, 136 patients (54% male, mean age 70.5 years, mean New York Heart Association class 2.7, mean ejection fraction 38.1%) with a preoperative diagnosis of moderate ischemic MR, without leaflet prolapse or pathology, underwent isolated CABG. Thirty-eight (28%) of 136 patients had intraoperative transesophageal echocardiography (TEE) before CABG, and 68 (50%) had postoperative transthoracic echocardiography (TTE) within 6 weeks of surgery. The subgroups of patients undergoing intraoperative TEE and postoperative TTE had preoperative characteristics similar to the overall group. The 30-day operative mortality was 2.9% (). Intraoperative TEE downgraded the severity of MR to mild or less (0 to 2+) in 89% (). On postoperative TTE, 40% () continued to have at least moderate MR (3 to 4+), 51% () improved somewhat to mild (2+) MR, and only 9% () had resolution of their MR (0 to 1+). The mean preoperative, intraoperative, and postoperative MR grades were 3.0+/-0.0, 1.4+/-1.0, and 2.3+/-0.8, respectively (P<0.001). CONCLUSIONS: CABG alone for moderate ischemic MR leaves many patients with significant residual MR and may not be the optimal therapy for most patients. Intraoperative TEE may significantly underestimate the severity of ischemic MR. A preoperative diagnosis of moderate MR may warrant concomitant mitral annuloplasty.

Selective targeting to the hyperactive beta-catenin/T-cell factor pathway in colon cancer cells.

Many colon cancers suffer mutations in either the adenomatous polyposis coli or beta-catenin genes that lead to stabilization of beta-catenin and activation of downstream T-cell factor (Tcf) target genes. We have developed a novel approach targeting colon cancer cells based on their aberrant beta-catenin/Tcf signaling pathway. A recombinant adenovirus, in which an apoptosis gene fadd is under the control of the promoter containing Tcf-responsive elements, selectively and efficiently kills colon cancer cells in which the beta-catenin/Tcf pathway is hyperactivated. Our data therefore provide a conceptual proof that aberrantly activated Wnt/beta-catenin/Tcf pathways can be used to selectively target colon cancers.

Hemograft crossmatching is unnecessary due to the absence of blood group antigens.

BACKGROUND: Homograft valves are subject to calcification and structural degeneration in the long term. Blood group matching is performed in many centers, and it remains controversial whether immunologic responses associated with potential blood group incompatibility contribute to the degeneration of unmatched homografts. We studied the expression of carbohydrate blood group antigens on valve endothelium of thawed aortic homograft valves and freshly harvested human cardiac valves. METHODS: Cryopreserved human aortic homograft valves and freshly harvested human aortic, pulmonary, mitral, and tricuspid valves were incubated with antibodies to A, B, and O blood group antigens. RESULTS: Cardiac microvascular endothelium stained positively with antiendothelial CD31 antibody in both cryopreserved and fresh tissue. Cryopreserved valve endothelial lining rarely stained positively for CD31, in contrast to fresh valves, which always stained positive. Cryopreserved or fresh cardiac microvascular endothelium strongly expressed A, B, or H antigens. In contrast, ABH antigens were not detectable on homograft or fresh cardiac valve endothelium. CONCLUSIONS: The absence of expression of carbohydrate antigen on valvular endothelium suggests that blood group incompatibility does not play a significant role in homograft degeneration.

Transgenic porcine valves show no signs of delayed cardiac xenograft rejection.

BACKGROUND: Glutaraldehyde fixation stiffens the structural integrity of porcine valves, although the solution also destroys tissue viability and accelerates calcification. Recently, we demonstrated that fresh cardiac valves from domestic pigs do not express the galactose alpha1, 3 galactose (alpha-Gal) antigen and may be immunologically unique. The absence of alpha-Gal explained why the valves remained pristine while the rest of the porcine heart was destroyed by primate immunoglobulin M (IgM) and complement membrane attack complex (MAC) within 60 minutes. We sought to clarify whether fresh porcine valves from transgenic pigs bearing human complement regulatory proteins (CD59/DAF) can survive longer in primates and whether porcine cardiac valves remained immunologically privileged after prolonged exposure. METHODS: Tissue sections from wild-type untransplanted (n = 6), wild-type transplanted (n = 3), and transgenic pigs expressing human CD59/DAF proteins transplanted (n = 3) porcine-to-primate cardiac grafts were examined by hematoxylin and eosin, and by immunohistochemistry for the porcine endothelial marker (GalNac), alpha-Gal, primate IgM and MAC. RESULTS: alpha-Gal antigens were highly expressed on the vascular, but not valvular, endothelium of transgenic pigs. Hearts from CD59/DAF transgenic pigs survived 5, 7, and 11 days, but showed increasing IgM and MAC deposition until failure. Valves remained morphologically intact at explant, and strong GalNac staining suggested an intact endothelial surface. However, the valves showed no signs of IgM- or MAC-mediated damage. CONCLUSIONS: Although hearts from transgenic pigs expressing human complement regulatory proteins can survive for days in the primate recipient, the xenografts eventually fail because of escalating attacks of primate IgM and MAC. The absence of the alpha-Gal antigens protects unfixed porcine valves from rejection.

Decreased porcine valve antigenicity with in vitro culture.

BACKGROUND: Porcine valvular prostheses may stimulate inflammation after implantation, with resultant accelerated structural degeneration. We investigated the expression of porcine major histocompatibility complex (MHC) class II molecules on valve leaflets and the possibility of decreasing valve antigenicity with in vitro culture. METHODS: Aortic and pulmonary valves were harvested from domestic pigs under sterile conditions and cultured in vitro with either porcine or baboon serum for 4 days. Valves were harvested daily and fixed in Carnoy's or formalin solution. Microtome sections of valves were examined by hematoxylin and eosin, and by immunohistochemistry for porcine MHC class II proteins and an endothelial marker, alpha-N-acetylgalactosaminyl glycoprotein (alpha-GalNac). RESULTS: Porcine aortic and pulmonary valves constitutively express alpha-GalNac proteins and porcine MHC class II antigens. Porcine valves continue to express both alpha-GalNac and MHC class II after 48 hours of culture in porcine serum. After 48-hour culture in baboon serum, however, MHC class II antigens became undetectable on valvular leaflets, although alpha-GalNac molecules were still detected. CONCLUSIONS: Porcine valvular endothelial cells remain viable after 2 days of in vitro culture. Porcine valves cultured with primate serum show decreased MHC class II antigenic expression. In vitro culture before glutaraldehyde fixation may decrease inflammation associated with implantation.

Artificial mitral valve chordae replacement made simple.

Mitral valve repair techniques are now widely applied in patients with myxomatous valve disease. The use of artificial chords to achieve correct height adjustment of the prolapsing anterior leaflet segment can often be challenging. We describe a simple method of artificial chord reconstruction performed after annuloplasty, which allows for easy identification of functional prolapse and accurate chordal height adjustment.