Initial investigation on the feasibility of porcine red blood cells from genetically modified pigs as an alternative to human red blood cells for transfusion.

The decline in blood donation rates and the ongoing shortage of blood products pose significant challenges to medical societies. One potential solution is to use porcine red blood cells (pRBCs) from genetically modified pigs as an alternative to human red blood cells (hRBCs). However, adverse immunological reactions remain a significant obstacle to their use. This study aimed to evaluate the compatibility of diverse genetically modified pRBCs with human serum. We acquired human complement-competent serum, complement 7 (C7)-deficient serum, and hRBCs from all ABO blood types. Additionally, we used leftover clinical samples from health checkups for further evaluation. pRBCs were collected from wild-type (WT) and genetically modified pigs: triple knockout (TKO), quadruple KO (QKO), and TKO/hCD55.hCD39 knockin (hCD55.hCD39KI). The extent of C3 deposition on RBCs was measured using flow cytometry after incubation in C7-deficient serum diluted in Ca++-enriched or Ca++-depleted and Mg++-enriched buffers. The binding of immunoglobulin (Ig) M/IgG antibody to RBCs after incubation in ABO-type human serum was evaluated using flow cytometry. Naïve human serum- or sensitized monkey serum-mediated hemolysis was also evaluated. Phagocytosis was assessed by incubating labeled RBCs with the human monocytic cell line THP-1 and measurement by flow cytometry. All three genetic modifications significantly improved the compatibility of pRBCs with human serum relative to that of WT pRBCs. The extent of IgM/IgG binding to genetically modified pRBCs was lower than that of WT pRBCs and similar to that of O-type hRBCs. Total and alternative pathway complement activation in all three genetically modified pRBCs was significantly weaker than that in WT pRBCs and did not differ from that in O-type hRBCs. The extent of serum-mediated hemolysis and phagocytosis of these genetically modified pRBCs was low and similar to that of O-type hRBCs. Sensitized monkey serum-mediated hemolysis in QKO and TKO/hCD55.hCD39KI pRBCs was higher than in O-type hRBCs but lower than in TKO pRBCs. The elimination of porcine carbohydrate antigens in genetically modified pigs significantly enhanced pRBC compatibility with naïve human sera, which was comparable to that of O-type hRBCs. These findings provide valuable insights into the development of pRBCs as potential alternatives to hRBCs.

Recent trends in perioperative blood transfusion during elective kidney transplantation.

Background: Accurately predicting the demand for blood transfusions is crucial for blood banks. Given the potential for emergency situations, it is imperative that blood banks maintain a sufficient inventory of blood products. In this study, we examined the use of perioperative transfusions in patients undergoing elective kidney transplants. Methods: Data on all complement-dependent cytotoxicity-crossmatched assays between 2013 and 2022 were collected. We excluded repeated assays and patients who did not undergo kidney transplantation. Transfusion records and transfusion adverse reactions were reviewed retrospectively. Results: In total, 30 patients underwent elective kidney transplantation from 2013 to 2022. The mean age of the patients was 48.1±9.7 years. The male-to-female ratio was 1.5:1. Four patients received transfusions intraoperatively, whereas eight patients were transfused postoperatively. The postoperative hemoglobin level of the transfusion group (n=9, 8.9±1.3) was significantly lower than that of the nontransfusion group (n=21, 10.4±1.2). The most commonly transfused blood product intraoperatively was leuko-reduced filtered red blood cells, followed by fresh frozen plasma. When the study period was divided into two halves based on the time of operation, the first half showed a higher number of significant transfusions. Conclusions: In most elective kidney transplant cases, surgery was conducted without the need for blood transfusion. The timing of transfusion, when necessary, shifted from during the operation to after the operation. The implementation of patient blood management, coupled with advancements in surgical techniques, appears to have impacted the pattern of perioperative transfusion.

Correction of superior sulcus deformity with orbital fat anatomic repositioning and fat graft applied to retro-orbicularis oculi fat for Asian eyelids.

BACKGROUND: "Sunken eyelid" is a term used to describe a deeply sunken area between the upper eyelid and upper edge of the orbital bone. The condition frequently is accompanied by blepharoptosis. Correction of a "sunken eyelid" generally is performed with a fat graft. However, surgical limitations such as a movement dysfunction of the upper eyelid or irregular skin surface often are encountered using the grafting method previously reported. An open technique is believed to be more precise than a closed procedure, and satisfactory results may be achieved by repositioning the upper eyelid fat and applying a fat graft to the retro-orbicularis orbital fat (ROOF). METHODS: Fat was harvested from the medial thigh area using a 10-ml syringe with minimal pressure. During the upper eyelid surgery, the orbital fat was relocated between the conjoined tendon of the levator aponeurosis and the lower orbicularis oculi muscle and skin flap. The ROOF was verified, and fat grafting then was performed from the upper medial side to the lower lateral side and from the medial aspect to the lateral direction using an 18-gauge Coleman needle. The sunken eyelids were classified into grades 1 to 4 according to the sunken depth (i.e., the distance between the most inferior orbital rim and the site of the most sunken area). The amount of fat graft and the technique of incorporating the fat were different according to sunken depth. RESULTS: From January 2006 to June 2008, 50 Korean and Chinese patients (48 women and 2 men) underwent fat repositioning and ROOF fat grafting using an open technique. The patients ranged in age from 24 to 67 years. The mean observation period was 4.7 months. The amount of fat graft for each palpebra was 0.3 to 3.3 ml, and the mean graft amount was 1.4 ml. Satisfactory results were obtained for most of the patients, but four patients required additional surgery. The reasons for the secondary surgery were a translocation of the fat graft to a lower position forming a lump (2 patients) and undercorrection (2 patients). The rate of fat absorption was relatively low and the complications very few compared with surgical cases involving a noninvasive method. CONCLUSIONS: More precise treatment is possible by dividing the depressed area of the upper eyelid according to the stage. Satisfactory results were achieved by relocating the orbital fat using an open method and adjusting the ROOF fat graft according to the stage.

Results of long-term follow-up observations of blepharoptosis correction using the palmaris longus tendon.

BACKGROUND: The frontalis sling procedure is a useful approach for correcting severe blepharoptosis. However, blepharoptosis often recurs after corrective surgery using the tensor fascia lata. Good results without recurrence after a modified Fox method were obtained using the palmaris longus tendon. This study examined the safety and validity of the surgical method using the palmaris longus tendon through long-term follow-up observations. METHODS: To reduce the rate of recurrence, the highest point on the pentagon of the Fox method was fixed to the frontalis fascia and frontalis muscle. It was fixed once again to the area 1 cm above the highest point. This approach remarkably reduces the incidence of recurrence by fixing the pentagon of the Fox method not only to the palmaris longus tendon but also to the frontalis fascia and again to the frontalis muscle. A modified Fox method using the palmaris longus tendon was used to treat 16 eyelids of 10 patients. A senior surgeon performed the procedure in all cases under local anesthesia. RESULTS: The mean follow-up period was 51 months (range = 18-86 months). There was no case of blepharoptosis recurrence and a good field of view was secured after surgery. Long-term follow-up revealed that the visual field had been well secured with a mean MRD1 of 3.1 mm. The eyelids were well maintained without any postoperative adverse reaction such as exposure keratitis. CONCLUSION: The palmaris longus tendon as useful donor material does not lead to recurrence of blepharoptosis, which is often encountered when the tensor fascia lata is used. The modified Fox method using the palmaris longus tendon can be an effective and valid surgical approach that produces both immediate and long-term results.