Sar1A overexpression in Chinese hamster ovary cells and its effects on antibody productivity and secretion.

Chinese hamster ovary (CHO) cells are the most widely used for therapeutic antibody production. In cell line development, engineering secretion processes such as folding-related protein upregulation is an effective way of constructing cell lines with high recombinant protein productivity. However, there have been few studies on the transport of recombinant proteins between the endoplasmic reticulum (ER) and the Golgi apparatus. In this study, Sar1A, a protein involved in COPII vesicle formation, was focused on to improve antibody productivity by enhancing COPII vesicle-mediated antibody transport from the ER to the Golgi apparatus, and to clarify its effect on the secretion process. The constructed Sar1A-overexpressing CHO cell lines were batch-cultured, in which they showed an increased specific antibody production rate. The intracellular antibody accumulation and the specific localization of the intracellular antibodies were investigated by chase assay using a translation inhibitor and observed by immunofluorescence-based imaging analysis. The results showed that Sar1A overexpression reduced intracellular antibody accumulation, especially in the ER. The effects of the engineered antibody transport on the antibody's glycosylation profile and the unfolded protein response (UPR) pathway were analyzed by liquid chromatography-mass spectrometry and UPR-related gene expression evaluation, respectively. Sar1A overexpression lowered glycan galactosylation and induced a stronger UPR at the end of the batch culture. Sar1A overexpression enhanced the antibody productivity of CHO cells by modifying their secretion process. This approach could also contribute to the production of not only monoclonal antibodies but also other therapeutic proteins that require transport by COPII vesicles.

Impact of initial aortic diameter and false-lumen area ratio on Type B aortic dissection prognosis.

OBJECTIVES: Medical treatment is the gold standard for uncomplicated acute Type B aortic dissection (ATBAD). Although endovascular treatment could become an alternative therapy, it is unclear which ATBAD patients should undergo endovascular intervention. We aimed to evaluate the outcomes of patients with uncomplicated ATBAD and identify the risk factors for major adverse events. METHODS: We retrospectively reviewed 134 consecutive patients who underwent initial treatment for uncomplicated ATBAD between 2004 and 2015. Follow-up rate was 98.5%, and the median follow-up period was 47 months. We evaluated the incidence of major adverse events (aortic-related death, aortic surgery and dilated aorta ≥ 55 mm) and identified the predictors of major adverse events using multivariable analysis. RESULTS: In-hospital mortality rate was 0.7% (1/134). During follow-up, 46 patients had major adverse events. The 1-, 3-, and 5-year rates of freedom from major adverse events were 79.8%, 71.4%, and 63.6%, respectively. The independent risk factors for major adverse events were initial aortic diameter ≥40 mm (hazard ratio 3.735, 95% confidence interval 1.888-7.390; P < 0.001) and false-lumen diameter > true-lumen diameter (hazard ratio 3.411, 95% confidence interval 1.491-7.806; P = 0.004). CONCLUSIONS: Initial aortic diameter ≥40 mm and false-lumen diameter > true-lumen diameter are predictors of major adverse events after uncomplicated ATBAD. Patients with these risk factors may benefit from early endovascular intervention. Clinical registration number: UMIN 000025388, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000029229.

Late Disruption of a Polyethylene Terephthalate Aortic Graft 30 Years after Initial Graft Placement.

A 71 year old male who had undergone extra-anatomic bypass grafting between the ascending aorta and the thoraco-abdominal aorta at 41 years of age for aortic coarctation was admitted with back pain and dyspnea. A 16 mm Cooley double velour knitted polyethylene terephthalate (PET) graft was used in the initial operation in 1983. Computed tomography showed disruption of the initial PET graft perforating the right atrium, and a pseudoaneurysm at the distal anastomosis. The patient was in acute cardiac failure because of left to right shunting. A two stage operation was performed. The first stage comprised emergency re-grafting and right atrium repair, and the second stage re-grafting for the pseudoaneurysm. The patient is doing well 48 months post-operatively; however, monitoring of the patient will continue for potential PET graft rupture.

Assessment of coronary flow velocity reserve by transthoracic Doppler echocardiography before and after coronary artery bypass grafting.

Little is known about the changes in the coronary flow velocity reserve (CFVR) of the left anterior descending artery (LAD) before and after coronary artery bypass grafting (CABG). The present study aimed to evaluate the feasibility of measuring the CFVR of the LAD using transthoracic Doppler echocardiography before and after CABG. We prospectively measured the CFVR before and after CABG in 56 patients. The flow velocity in the LAD was measured using transthoracic Doppler echocardiography both at rest and during intravenous infusion of adenosine. The CFVR was calculated as the ratio of hyperemic to the basal peak and mean diastolic flow velocities. Coronary angiography was also performed to assess graft patency after CABG in all patients. Furthermore, we compared the differences between the pre- and postoperative CFVR in patients with and without a diffusely diseased LAD (lesion length >2 cm). All grafts were angiographically patent. The postoperative peak and mean CFVR were significantly increased compared to the preoperative peak and mean CFVR (both peak and mean 2.7 ± 0.9 vs 1.5 ± 0.6, respectively; p<0.0001). The preoperative peak CFVR was significantly lower in patients with a diffusely diseased LAD than in those without a diffusely diseased LAD (1.3 ± 0.5 vs 1.6 ± 0.5, respectively; p=0.04). The postoperative peak CFVR of the 2 groups was almost identical (2.5 ± 0.6 vs 2.9 ± 1.0; p=0.07). In conclusion, assessment of the CFVR of the LAD using transthoracic Doppler echocardiography was useful after CABG for confirming graft patency.