Malignant triton tumor in the abdominal wall: A case report.

BACKGROUND: Malignant triton tumors (MTTs) comprise a subgroup of malignant peripheral nerve sheath tumors (MPNSTs) that exhibits rhabdomyosarcomatous differentiation and follow an aggressive course. MTTs are primarily located along peripheral nerves. Cases of MTTs in the abdominal wall have not been reported. MTT has a poorer prognosis than classic MPNSTs, and accurate diagnosis necessitates a keen understanding of the clinical history and knowledge of its differential diagnosis intricacies. Treatment for MTTs mirrors that for MPNSTs and is predominantly surgical. CASE SUMMARY: A 49-year-old woman presented with a subcutaneous mass in her lower abdominal wall and a pre-existing surgical scar that had grown slowly over 3-4 months before the consultation. She had previously undergone radical hysterectomy and concurrent chemo-radiotherapy for cervical cancer approximately 5 years prior to the consultation. Abdominal computed tomography (CT) showed a 1.3 cm midline mass in the lower abdomen with infiltration into the rectus abdominis muscle. There was no sign of metastasis (T1N0M0). An incisional biopsy identified sporadic MTT of the lower abdomen. A comprehensive surgical excision with a 3 cm margin inclusive of the peritoneum was executed. Subsequently, the general surgeon utilized an approach akin to the open peritoneal onlay mesh technique. The patient underwent additional treatment with an excision shaped as a mini-abdominoplasty for the skin defect. No complications arose, and annual follow-up CTs did not show signs of recurrence or metastasis. CONCLUSION: An abdominal MTT was efficaciously treated with extensive excision and abdominal wall reconstruction, eliminating the need for postoperative radiotherapy.

Improvement in Biocompatibility and Biointegration of Human Acellular Dermal Matrix through Vacuum Plasma Surface Treatment.

Efforts are ongoing to enhance the functionality of human acellular dermal matrices (hADMs), which are extensively utilized in reconstructive surgeries. Among these efforts, plasma treatments, particularly vacuum plasma treatments, have recently emerged in the medical field. This study aims to investigate the efficacy of a vacuum plasma treatment in enhancing the biocompatibility and biointegration of hADMs. Utilizing a plasma activator (ACTILINK reborn, Plasmapp Co., Ltd., Daejeon, Republic of Korea), hADMs were treated and evaluated through in vitro and in vivo analyses. Hydrophilicity changes were gauged by the blood absorption times, while SEM imaging was used to analyze physical surface deformation. Protein adsorption was measured with fluorescently labeled bovine serum albumin and fibronectin. For the in vivo study, mice were implanted with plasma-treated and untreated hADMs, and the post-implantation effects were analyzed through histological and immunofluorescence microscopy. The plasma-treated hADMs demonstrated a significantly enhanced hydrophilicity compared to the untreated samples. SEM imaging confirmed the maintenance of the microroughness after the treatment. The treated hADMs showed a significant reduction in fibronectin adsorption, a critical factor for cellular adhesion. In vivo, the plasma-treated hADMs exhibited reduced capsule formation and enhanced fibroblast infiltration, indicating improved biocompatibility and integration. These findings highlight the potential of a plasma treatment to enhance the performance of hADMs in clinical settings, offering a promising avenue for improving reconstructive surgery outcomes.

Customized Reconstruction of Lower Eyelid Defects.

BACKGROUND: A lower eyelid defect is a loss of skin, muscle, and underlying structures that can occur due to trauma, malignant or benign tumors, burns, or other causes. The conventional surgical treatment of lower lid defects has several limitations, including visible scarring, narrowing of the eye, and ectropion. Here, we combined the use of a customized mid-face lift with a free mucochondral graft to overcome the disadvantages of existing methods. METHODS: Forty patients underwent reconstructive surgery using a customized mid-face lift with or without a free mucochondral graft for a lower lid defect between April 2013 and October 2020. Patients were discharged shortly after surgery and were expected to visit the outpatient clinic periodically for 12 months. RESULTS: The causes of lower eyelid defects were malignancy, trauma, foreign body granuloma, and other causes. Four patients reported complications, including 2 cases of chemosis, 1 case of a hematoma, and 1 case of corneal abrasion, who reportedly performed well after 2 weeks of conservative therapy. No patient required revision during the average follow-up period. CONCLUSIONS: Customized reconstruction demonstrated a better aesthetic reconstruction of the lower eyelid. This method represents a good option for reconstructing lower lid defects.

Effects of Midcheek Lift According to Dissection Plane and Range: An Anatomical Study.

BACKGROUND: Midcheek lift has been performed for cosmetic or reconstructive surgery of the lower eyelid. For midcheek lift through the subciliary incision, preperiosteal and subperiosteal dissections are the most often implemented, with good clinical outcomes. However, a comparative assessment of the effects of these 2 methods had not been conducted. OBJECTIVES: In this study we compared the effects of midcheek lift according to preperiosteal or subperiosteal plane and range of midfacial dissection. METHODS: Forty hemifaces of 20 fresh cadavers were dissected. One side of the hemiface underwent preperiosteal dissection, and the other side underwent subperiosteal dissection. After dissections of 5, 10, 15, 20, and 30 mm and all of the midcheek area from the inferior orbital rim, the length of the elevated lid-cheek junction was measured by placing upward traction on the lateral portion of the lower lid. RESULTS: In both methods, the length of the midcheek lift increased as the dissection progressed, and the length of the lift on the lateral side was greater than that on the medial side. The length of the pulled skin in the preperiosteal group was the greatest in most cases. However, in the full dissection cases, the midcheek lift length was not statistically different between the 2 surgical methods, especially on the lateral side. CONCLUSIONS: Flap elevation in lower blepharoplasty surgery can be predicted based on the surgical method and dissection range. Implementing a surgical plan that takes this into account can enhance both reconstruction and aesthetic surgery outcomes in the midcheek area.

Introduction of Deep Learning-Based Infrared Image Analysis to Marginal Reflex Distance1 Measurement Method to Simultaneously Capture Images and Compute Results: Clinical Validation Study.

Marginal reflex distance1 (MRD1) is a crucial clinical tool used to evaluate the position of the eyelid margin in relation to the cornea. Traditionally, this assessment has been conducted manually by plastic surgeons, ophthalmologists, or trained technicians. However, with the advancements in artificial intelligence (AI) technology, there is a growing interest in the development of automated systems capable of accurately measuring MRD1. In this context, we introduce novel MRD1 measurement methods based on deep learning algorithms that can simultaneously capture images and compute the results. This prospective observational study involved 154 eyes of 77 patients aged over 18 years who visited Chungnam National University Hospital between 1 January 2023 and 29 July 2023. We collected four different MRD1 datasets from patients using three distinct measurement methods, each tailored to the individual patient. The mean MRD1 values, measured through the manual method using a penlight, the deep learning method, ImageJ analysis from RGB eye images, and ImageJ analysis from IR eye images in 56 eyes of 28 patients, were 2.64 ± 1.04 mm, 2.85 ± 1.07 mm, 2.78 ± 1.08 mm, and 3.07 ± 0.95 mm, respectively. Notably, the strongest agreement was observed between MRD1_deep learning (DL) and MRD1_IR (0.822, p < 0.01). In a Bland-Altman plot, the smallest difference was observed between MRD1_DL and MRD1_IR ImageJ, with a mean difference of 0.0611 and ΔLOA (limits of agreement) of 2.5162, which was the smallest among all of the groups. In conclusion, this novel MRD1 measurement method, based on an IR camera and deep learning, demonstrates statistical significance and can be readily applied in clinical settings.

Smartphone-Based LiDAR Application for Easy and Accurate Wound Size Measurement.

The accurate assessment of wound size is a critical step in advanced wound care management. This study aims to introduce and validate a Light Detection and Ranging (LiDAR) technique for measuring wound size. Twenty-eight wounds treated from December 2022 to April 2023 at the Chungnam National University Hospital were analyzed. All the wounds were measured using three techniques: conventional ruler methods, the LiDAR technique, and ImageJ analysis. Correlation analysis, linear regression, and Bland-Altman plot analysis were performed to validate the accuracy of the novel method. The measurement results (mean ± standard deviation) obtained using the ruler method, LiDAR technique, and ImageJ analysis were 112.99 ± 110.07 cm2, 73.59 ± 72.97 cm2, and 74.29 ± 72.15 cm2, respectively. The Pearson correlation coefficient was higher for the LiDAR application (0.995) than for the conventional ruler methods (mean difference, -5.0000 cm2), as was the degree of agreement (mean difference, 38.6933 cm2). Wound size measurement using LiDAR is a simple and reliable method that will enable practitioners to conveniently assess wounds with a flattened and irregular shape with higher accuracy. However, non-flattened wounds cannot be assessed owing to the technical limitations of LiDAR.

The Effect of Botulinum Toxin A on NADPH oxidase system and Ischemia Reperfusion Injury.

BACKGROUND: While studies aimed at overcoming ischemia-reperfusion (IR) injury using various materials are becoming popular, studies using botulinum toxin type A (BoNTA) are still limited. This study tested the hypotheses that BoNTA can protect flaps from IR injury by inhibiting the NADPH oxidase system and suppressing ROS (reactive oxygen species) production. MATERIAL AND METHODS: The subjects were Sprague-Dawley rats (n = 76). In 4 rats, the effects of different dose of BoNTA on superoxide production was evaluated through lucigenin enhanced chemiluminescence assay (LECL) using SD rats' thoracic aorta ring. In 60 SD rats, The BoNTA and normal saline-pretreated superficial inferior epigastric artery (SIEA) flaps were clamped for 0, 1, and 4 hours, and reperfused. On the 5th day after the opeartion, well-maintained flaps were grossly inspected, survival rates were analyzed, and histological analysis was also performed. In 12 rats, after making IR injury through the same model, SIEA flap segments and femoral vessels were obtained, and ROS production was evaluated through LECL and dihydroethidium (DHE) staining. RESULTS: In LECL, the experimental group produced a smaller amount of superoxide than the control group through NADPH oxidase inhibition (p < .05). There was no significant difference between the experimental and control group in the 0, and 1 hour IR groups, but the experimental group (90%) showed a higher survival rate than the control group (60%) in the 4 hours IR group (p = .028). In the measurement of ROS production through LECL and DHE staining, there was no significant difference in the 0, and 1 hour IR groups, but a significant difference was shown in the 4 hours IR group in both the SIEA flaps and femoral vessels (p < .05). SUMMARY: This study verified hypothesis that BoNTA can protect flaps from IR injury by inhibiting the NADPH oxidase system and suppressing ROS production. Based on this research model, future research should be expanded into studies on subtypes or subunits of NADPH oxidase, and the findings from the present study are expected to contribute and lead to clinical studies on BoNTA, which has already been proven to be clinically safe.

Accuracy and availability of automated urine output monitoring in the operating room using a smart scale.

PURPOSE: Urine output (UO) is an important intraoperative parameter that is not yet electronically monitored. We compared an automatic urinometer (AU) based on a smart scale with a manual urinometer (MU). PATIENTS AND METHODS: This prospective study investigated the hourly UO of 35 preoperative patients with an indwelling urinary catheter using AU, MU, and cylinder measurements. Data were analyzed using the Bland-Altman method. A questionnaire related to the use of the AU was completed by medical staff (n=25). RESULTS: Compared to the cylinder measurements, the differences in measurements by the AU and the MU were -6.31 â€‹± â€‹15.03 â€‹mL/h (p=0.018) and 20.26 â€‹± â€‹26.81 â€‹mL/h (p=0.001), respectively. The r values for the comparison of cylinder measurements with AU and MU values were 0.985 (p<0.001) and 0.968 (p<0.001), respectively. Bland-Altman analyses showed that cylinder measurements had better agreement with the AU measurements than with the MU measurements. Also, the medical staff reported that the use of the AU was easier to learn than the use of the MU (p<0.001). CONCLUSIONS: Compared to the MU values, AU values were noninferior; they had significantly less bias and temporal deviation. Additionally, the medical staff reported that the use of the AU was easier to learn than the use of the MU.

In Vivo Efficacy of an Injectable Human Acellular Dermal Matrix.

BACKGROUND: Human acellular dermal matrix (hADM) has found applications in a variety of settings, particularly in breast surgery. The most common hADM is a sheet. Recently, an injectable hADM has been introduced; we compared the biocompatibility and long-term structural integrity of, an injectable hADM and a sheet-type hADM in mice. METHODS: An injectable hADM (experimental group) and a sheet-type hADM (control group) were implanted into sub-panniculus pockets on the backs of 50 mice. The animals were sacrificed 2, 4, 8, 12, or 24 weeks later and the hADMs and surrounding tissues were recovered and stained for histopathological analyses. The microscopic endpoints included the thickness of the hADM and capsule around the hADM, and the extents of fibroblast proliferation and neovascularization. RESULTS: No animal developed a complication or infection. The capsule was significantly thinner in the experimental than the control group. There were no significant differences between groups in the hADM thickness. Microscopically, the fibroblast density inside the hADM was significantly higher in the experimental group. The fibroblasts inside of the hADM lay significantly deeper in the experimental group. Similarly, the experimental group exhibited significantly deeper microvessels inside the hADM. CONCLUSIONS: The injectable hADM had a thinner capsule thickness (more biocompatible), than the sheet-type hADM. It maintained its thickness as well as the sheet-type hADM and had a more fibroblast proliferation and neovascularization. This means the tissue incorporation and long-term structural integrity of the injectable hADM may be as good as or better than that of the sheet-type hADM. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A multi-targeting bionanomatrix coating to reduce capsular contracture development on silicone implants.

BACKGROUND: Capsular contracture is a critical complication of silicone implantation caused by fibrotic tissue formation from excessive foreign body responses. Various approaches have been applied, but targeting the mechanisms of capsule formation has not been completely solved. Myofibroblast differentiation through the transforming growth factor beta (TGF-ß)/p-SMADs signaling is one of the key factors for capsular contracture development. In addition, biofilm formation on implants may result chronic inflammation promoting capsular fibrosis formation with subsequent contraction. To date, there have been no approaches targeting multi-facted mechanisms of capsular contracture development. METHODS: In this study, we developed a multi-targeting nitric oxide (NO) releasing bionanomatrix coating to reduce capsular contracture formation by targeting myofibroblast differentiation, inflammatory responses, and infections. First, we characterized the bionanomatrix coating on silicon implants by conducting rheology test, scanning electron microcsopy analysis, nanoindentation analysis, and NO release kinetics evaluation. In addition, differentiated monocyte adhesion and S. epidermidis biofilm formation on bionanomatrix coated silicone implants were evaluated in vitro. Bionanomatrix coated silicone and uncoated silicone groups were subcutaneously implanted into a mouse model for evaluation of capsular contracture development for a month. Fibrosis formation, capsule thickness, TGF-ß/SMAD 2/3 signaling cascade, NO production, and inflammatory cytokine production were evaluated using histology, immunofluorescent imaging analysis, and gene and protein expression assays. RESULTS: The bionanomatrix coating maintained a uniform and smooth surface on the silicone even after mechanical stress conditions. In addition, the bionanomatrix coating showed sustained NO release for at least one month and reduction of differentiated monocyte adhesion and S. epidermidis biofilm formation on the silicone implants in vitro. In in vivo implantation studies, the bionanomatrix coated groups demonstrated significant reduction of capsule thickness surrounding the implants. This result was due to a decrease of myofibroblast differentiation and fibrous extracellular matrix production through inhibition of the TGF-ß/p-SMADs signaling. Also, the bionanomatrix coated groups reduced gene expression of M1 macrophage markers and promoted M2 macrophage markers which indicated the bionanomatrix could reduce inflammation but promote healing process. CONCLUSIONS: In conclusion, the bionanomatrix coating significantly reduced capsular contracture formation and promoted healing process on silicone implants by reducing myfibroblast differentiation, fibrotic tissue formation, and inflammation. A multi-targeting nitric oxide releasing bionanomatrix coating for silicone implant can reduce capsular contracture and improve healing process. The bionanomatrix coating reduces capsule thickness, α-smooth muscle actin and collagen synthesis, and myofibroblast differentiation through inhibition of TGF-ß/SMADs signaling cascades in the subcutaneous mouse models for a month.

Effects of preoperative education using virtual reality on preoperative anxiety and information desire: a randomized clinical trial.

This study aimed to investigate the effect of preoperative education using virtual reality (VR) on preoperative anxiety and information desire. The participants were randomly assigned to the VR group and control group. The VR group received preoperative education using VR content describing preoperative and postoperative processes and their management, and the control group received preoperative education with traditional verbal education. Preoperative anxiety and information desire were measured using the Amsterdam Preoperative Anxiety and Information Scale (APAIS). Additionally, patient satisfaction was investigated. Preoperative anxiety (APAIS-A) and information desire (APAIS-I) scores were statistically significantly different between the VR group and the control group (p < 0.001). Patient satisfaction was not statistically significant (p = 0.147). Preoperative education using VR effectively reduced preoperative anxiety and information desire.Trial registration CRIS, KCT0007489. Registered 30 June 2022. http://cris.nih.go.kr/cris/ .

Reconstruction of complex knee wounds with a distally based gracilis flap and gastrocnemius myocutaneous flap: A case report.

A gastrocnemius muscle flap is a versatile option for covering the proximal one-third of the lower leg and around the knee. On the other hand, it is of limited use in patients with short gastrocnemius muscle or insufficient volume. The authors present a case in which a knee soft tissue defect occurred in a very thin patient and was reconstructed using a gastrocnemius myocutaneous flap and a distally based gracilis flap as a supplementary flap.

Autophagy Dysfunction in a Diabetic Peripheral Neuropathy Model.

BACKGROUND: The relationship between autophagy and diabetic peripheral neuropathy (DPN) has been highlighted in few reports. Using an animal model, the authors investigated the relationship between autophagy and DPN, focused particularly on changes in autophagy in Schwann cells. METHODS: The ultrastructural features of DPN mice were evaluated in vivo using transmission electron microscopy. Dysfunction of autophagy in DPN was evaluated using immunofluorescence microscopy and Western blot analysis of proteins related to autophagy, including Beclin1, LC3, and p62. Reactive oxygen species levels were measured in vitro in glucose-treated Schwann cells. Dysfunction of autophagy in glucose-treated Schwann cells was examined by immunofluorescence microscopy and Western blot analysis. RESULTS: Reduced myelin thickness and axonal shrinkage were observed in the sciatic nerves of DPN mice. Reactive oxygen species levels were increased in Schwann cells treated with high glucose ( P < 0.05). The expression of Beclin1 was increased in DPN mice and Schwann cells treated with high glucose ( P < 0.05), whereas the expression of LC3-II/LC3-I ratio and p62 were decreased in DPN mice and Schwann cells treated with high glucose ( P < 0.05). CONCLUSIONS: These results suggest that increased levels of reactive oxygen species induced by high glucose may contribute to autophagy dysfunction in Schwann cells. Autophagy dysfunction especially in Schwann cells may be an underlying cause of DPN. CLINICAL RELEVANCE STATEMENT: This study presents the pathological mechanism of diabetic peripheral neuropathy.

Alar crease as a donor site for the extension limb of modified nasolabial V-Y advancement flap.

BACKGROUND: The traditional nasolabial V-Y advancement flap is widely used for midface reconstruction, particularly for the lower third of the nose and upper lip, as its color and texture are similar to these areas. However, it provides insufficient tissue to cover large defects and cannot restore the nasal convexity, nasal ala, and adjacent tissues. The purpose of this study is to investigate the modified nasolabial V-Y advancement flap with extension limbs the along alar crease for the reconstruction of complex midface defects. METHODS: A retrospective analysis of 18 patients, who underwent reconstruction with the modified nasolabial V-Y advancement flap, was performed between September 2014 and December 2022. An extension limb was added along the alar crease, adjacent to the defect area, and was hinged down as a transposition flap at the end of the advancement flap. RESULTS: The extension limb along the alar crease successfully covered large and complicated defects, including those of the ala, the alar rim, the alar base, the nostrils, and the upper lip, with minor complications. CONCLUSION: The alar crease is a good donor site for the reconstruction of large and complex nasal and upper lip defects.

Ultrathin Nanostructured Films of Hyaluronic Acid and Functionalized ß-Cyclodextrin Polymer Suppress Bacterial Infection and Capsular Formation of Medical Silicone Implants.

A type of ultrathin films has been developed for suppressing capsule formation induced by medical silicone implants and hence reducing the inflammation response to such formation and the differentiation to myofibroblasts. The films were each fabricated from hyaluronic acid (HA) and modified ß-cyclodextrin (Mod-ß-CyD) polymer which was synthesized with a cyclodextrin with partially substituted quaternary amine. Ultrathin films comprising HA and Mod-ß-CyD or poly(allylamine hydrochloride) (PAH) were fabricated by using a layer-by-layer dipping method. The electrostatic interactions produced from the functional groups of Mod-ß-CyD and HA influenced the surface morphology, wettability, and bio-functional activity of the film. Notably, medical silicone implants coated with PAH/HA and Mod-ß-CyD multilayers under a low pH condition exhibited excellent biocompatibility and antibiofilm and anti-inflammation properties. Implantation of these nanoscale film-coated silicones showed a reduced capsular thickness as well as reduced TGFß-SMAD signaling, myofibroblast differentiation, biofilm formation, and inflammatory response levels. We expect our novel coating system to be considered a strong candidate for use in various medical implant applications in order to decrease implant-induced capsule formation.

Designing with relaxed skin tension line in perforator-based island flap for sacral sore reconstruction: A STROBE-compliant observational study.

Many various types of operative techniques have been performed used to treat make-up for sacral defects. Perforator-based flaps with flap transposition, but achieving an optimal flap design and tension-free flap closure without skeletonizing the perforator requires a great deal of clinical experience. In this study, we demonstrate perforator selection based on considerations of the relaxed skin tension line (RSTL), which has proven to be a suitable method of achieving an efficient flap design that enables primary closure. Twenty-five perforator-based flap procedures were performed on 25 patients at a single institution from February 2018 to January 2021. The medical records of patients were retrospectively reviewed. Twenty-three flaps survived completely. Two flaps developed partial tip necrosis but recovered after secondary healing, and 1 patient developed temporary congestion, which resolved spontaneously. No recipient or donor site recurrence or dehiscence was identified during follow-up. We report our clinical experiences of perforator-based flap use in the sacral region. When selecting an appropriate perforating vessel, 2 important points should be considered, that is, a flap long axis parallel to RSTLs and defect shape. According to the method presented in this paper, perforator-based flaps can be transposed safely and easily with few complications and serve as useful practice models to cover sacral defects.

A Regio- and Diastereoselective Stille Coupling/Intramolecular Diels-Alder Cascade for the Generation of Fused Pyridines and Application in the Synthesis of (+)-Lycopladine A and (-)-Lycoposerramine R.

2-Pyrones with a chiral branched allylic silyl ether substituent underwent intramolecular Diels-Alder reactions with remarkably high π-facial- and endo-selectivities. The resulting diastereomerically and enantiomerically pure cycloadducts were transformed into the natural products (+)-lycopladine A and (-)-lycoposerramine R.

Aesthetic Removal of Foreign Body Granulomas of Forehead Via Pretrichial Approach.

ABSTRACT: In the field of plastic surgery, various filler types have been developed, which are widely used for cosmetic or reconstruction purposes. However, unregulated substances often injected by unlicensed practitioners may cause difficult-to-treat side effects, such as foreign body granulomas. Since the forehead is an exposed area and the lesions are likely extensive, complete surgical removal with inconspicuous scar can be difficult. In addition, pharmacological treatments, such as steroids, have only a temporary effect. The authors report successful cases of foreign body removal combined with subcutaneous forehead lift via a pretrichial approach for cosmetic satisfaction.Ten patients who had received illegal filler injections that resulted in chronic granulomas on the forehead were studied. The granulomas were confirmed using sonography, and simultaneous foreign body removal and subcutaneous forehead lifts using pretrichial incisions were planned. For the surgical method, the forehead flap was carefully elevated to a uniform thickness in the subcutaneous plane via a pretrichial incision, and the foreign body was removed, paying attention to the forehead contour and nerve damage; excess skin was excised from the top of the flap to tighten the remaining skin on the forehead.None of the patients developed complications, such as skin necrosis, infection, hematoma, or wound dehiscence, during the follow-up period. The functional and aesthetic outcomes were satisfactory in all the patients.The subcutaneous forehead lift via a pretrichial incision seems to facilitate foreign body removal and improve the forehead deformity by tightening the remaining skin.

CRIF1 Deficiency Increased Homocysteine Production by Disrupting Dihydrofolate Reductase Expression in Vascular Endothelial Cells.

Elevated plasma homocysteine levels can induce vascular endothelial dysfunction; however, the mechanisms regulating homocysteine metabolism in impaired endothelial cells are currently unclear. In this study, we deleted the essential mitoribosomal gene CR6 interacting factor 1 (CRIF1) in human umbilical vein endothelial cells (HUVECs) and mice to induce endothelial cell dysfunction; then, we monitored homocysteine accumulation. We found that CRIF1 downregulation caused significant increases in intracellular and plasma concentrations of homocysteine, which were associated with decreased levels of folate cycle intermediates such as 5-methyltetrahydrofolate (MTHF) and tetrahydrofolate (THF). Moreover, dihydrofolate reductase (DHFR), a key enzyme in folate-mediated metabolism, exhibited impaired activity and decreased protein expression in CRIF1 knockdown endothelial cells. Supplementation with folic acid did not restore DHFR expression levels or MTHF and homocysteine concentrations in endothelial cells with a CRIF1 deletion or DHFR knockdown. However, the overexpression of DHFR in CRIF1 knockdown endothelial cells resulted in decreased accumulation of homocysteine. Taken together, our findings suggest that CRIF1-deleted endothelial cells accumulated more homocysteine, compared with control cells; this was primarily mediated by the disruption of DHFR expression.