Macropinocytic cups function as signal platforms for the mTORC2-AKT pathway to modulate LPS-induced cytokine expression in macrophages.

Macropinocytosis is a large-scale endocytosis process that is primarily observed in phagocytes as part of their cellular function to ingest antigens. Once phagocytes encounter gram-negative bacteria, the receptor proteins identify lipopolysaccharides (LPSs), which trigger radical membrane ruffles that gradually change to cup-like structures. The open area of the cups closes to generate vesicles called macropinosomes. The target bacteria are isolated by the cups and engulfed by the cells as the cups close. In addition to its ingestion function, macropinocytosis also regulates the AKT pathway in macrophages. In the current study, we report that macropinocytic cups are critical for LPS-induced AKT phosphorylation (pAKT) and cytokine expression in macrophages. High-resolution scanning electron microscope (SEM) observations detailed the macropinocytic cup structures induced by LPS stimulation. Confocal microscopy revealed that AKT and the kinase molecule mTORC2 were localized in the cups. The biochemical analysis showed that macropinocytosis inhibition blocked LPS-induced pAKT. RNA-Seq, qPCR, and ELISA analyses revealed that the inhibition of macropinocytosis or the AKT pathway causes a decrease in the expression of pro-inflammatory cytokines IL-6 and IL-1α. Moreover, activation of the transcription factor NF-κB, which regulates the cytokine expression downstream of the AKT/IκB pathway, was hindered when macropinocytosis or AKT were inhibited. These results indicate that LPS-induced macropinocytic cups function as signal platforms for the AKT pathway to regulate the cytokine expression by modulating NF-κB activity in LPS-stimulated macrophages. Based on these findings, we propose that macropinocytosis may be a good therapeutic target for controlling cytokine expression.

GTPase-activating protein ARAP1 regulates circular dorsal ruffles as a nutrient uptake mechanism in the Hep3B hepatocellular carcinoma cell line.

Circular dorsal ruffles (CDRs), large-scale rounded membrane ruffles, function as precursors of macropinocytosis. We recently reported that CDRs are exposed in the Hep3B hepatocellular carcinoma cell line, while not in other hepatocellular carcinoma cell lines, indicating that the CDRs in Hep3B are associated with malignant potential. In this study, we investigated the cellular function of CDRs in Hep3B cells by focusing on the molecular mechanisms of the GTPase-activating protein ARAP1. ARAP1 was localized to the CDRs, the sizes of which were reduced by deletion of this protein. High-resolution scanning electron micrographs revealed that CDRs comprise small vertical lamellipodia, the expression pattern of which was disrupted in ARAP1 KO cells. Extracellular solute uptake, rate of cell growth, and malignant potential were attenuated in the KO cells. ARAP1 is also localized in Hep3B cell mitochondria, although not in those of the Huh7 hepatocellular carcinoma cell line. On the basis of these findings, we propose that the aberrant expression of ARAP1 in Hep3B cells modulates CDRs, thereby resulting in an excess uptake of nutrients as an initial event in cancer development. SUMMARY STATEMENT: ARAP1 regulates circular dorsal ruffles (CDRs) in the Hep3B HCC cell line and deletion of this protein attenuates malignant potential, thereby indicating the involvement of CDRs in cancer development.

Multiple Lymphaticovenular Anastomoses for Chyluria in Klippel-Trenaunay Syndrome.

ABSTRACT: Klippel-Trenaunay syndrome (KTS) is characterized by port-wine stains, mixed vascular malformations, and soft tissue and bone hypertrophy. Klippel-Trenaunay syndrome is occasionally complicated by chyluria, for which there is no effective treatment currently. We report a case of KTS complicated by intractable chyluria and hematuria due to a lymphatic-ureteral fistula. The patient was successfully treated with multiple lymphaticovenular anastomoses (LVAs).A 66-year-old woman with an enlarged left lower extremity since childhood was diagnosed with KTS. At 60 years of age, she developed chyluria (urine albumin, 2224 µg/mL) and hematuria. Lymphoscintigraphy showed a lymphatic-ureteral fistula near the ureterovesical junction. Conservative treatment was ineffective. She also developed left lower extremity lymphedema, which gradually worsened. Leg cellulitis and purulent pericarditis developed because of hypoalbuminemia (minimum serum albumin level, 1.3 g/dL).We performed 14 LVAs in 2 surgeries to reduce lymphatic fluid flow through the lymphatic-ureteral fistula. The chyluria and hematuria resolved soon after the second operation, and the urine albumin level decreased (3 µg/mL). After 28 months, she had no chyluria or hematuria recurrence and her serum albumin level improved (3.9 g/dL). Multiple LVAs can definitively treat chyluria caused by a lymphatic-ureteral fistula in patients with KTS.

Process to Remove the Size Variants Contained in the Antibody-Chelator Complex PCTA-NCAB001 for Radiolabeling with Copper-64.

Understanding the physicochemical properties of antibody-drug conjugates is critical to assess their quality at manufacturing and monitor them during subsequent storage. For radiometal-antibody complexes, it is important to control the properties of the antibody-chelator conjugate to maintain the quality of the final product. We have been developing 64Cu-labeled anti-epidermal growth factor receptor antibody NCAB001 (64Cu-NCAB001) for the early diagnosis and therapy of pancreatic cancer with positron-emission tomography. Here, we characterized the larger size variants contained in the antibody-chelator conjugate PCTA-NCAB001 by multi-angle light scattering coupled with size-exclusion chromatography. Secondly, we developed a chromatographic method to remove these size variants. Lastly, we demonstrated the stability of PCTA-NCAB001 after the removal of size variants. Dimer and oligomers were identified in PCTA-NCAB001. These larger size variants, together with some smaller size variants, could be removed by hydrophobic interaction chromatography. The PCTA-NCAB001 product, after the removal of these size variants, could be stored at 4 °C for six months. The methods developed here can be applied to assure the quality of PCTA-NCAB001 and other antibody-drug conjugates to facilitate the development of antibody-radiometal conjugates for positron-emission tomography and radioimmunotherapy of malignant cancers.

Metronomic capecitabine with rapamycin exerts an immunosuppressive effect by inducing ferroptosis of CD4+ T cells after liver transplantation in rat.

Liver transplantation is one of the most effective treatments for hepatocellular carcinoma (HCC). The balance between inhibiting immune rejection and preventing tumor recurrence after liver transplantation is the key to determining the long-term prognosis of patients with HCC after liver transplantation. In our previous study, we found that capecitabine (CAP), an effective drug for the treatment of HCC, could exert an immunosuppressive effect after liver transplantation by inducing T cell ferroptosis. Recent studies have shown that ferroptosis is highly associated with autophagy. In this study, we confirmed that the autophagy inducer rapamycin (RAPA) combined with metronomic capecitabine (mCAP) inhibits glutathione peroxidase 4 (GPX4) and promotes ferroptosis in CD4+ T cells to exert immunosuppressive effects after rat liver transplantation. Compared with RAPA or mCAP alone, the combination of RAPA and mCAP could adequately reduce liver injury in rats with acute rejection after transplantation. The CD4+ T cell counts in peripheral blood, spleen, and transplanted liver of recipient rats significantly decreased, and the oxidative stress level and ferrous ion concentration of CD4+ T cells significantly increased in the combination group. In vitro, the combination of drugs significantly promoted autophagy, decreased GPX4 protein expression, and induced ferroptosis in CD4+ T cells. In conclusion, the autophagy inducer RAPA improved the mCAP-induced ferroptosis in CD4+ T cells. Our results support the concept of ferroptosis as an autophagy-dependent cell death and suggest that the combination of ferroptosis inducers and autophagy inducers is a new research direction for improving immunosuppressive regimens after liver transplantation.

Metronomic capecitabine inhibits liver transplant rejection in rats by triggering recipients' T cell ferroptosis.

BACKGROUND: Capecitabine (CAP) is a classic antimetabolic drug and has shown potential antirejection effects after liver transplantation (LT) in clinical studies. Our previous study showed that metronomic CAP can cause the programmed death of T cells by inducing oxidative stress in healthy mice. Ferroptosis, a newly defined non-apoptotic cell death that occurs in response to iron overload and lethal levels of lipid peroxidation, is an important mechanism by which CAP induces cell death. Therefore, ferroptosis may also play an important role in CAP-induced T cell death and play an immunosuppressive role in acute rejection after trans-plantation. AIM: To investigate the functions and underlying mechanisms of antirejection effects of metronomic CAP. METHODS: A rat LT model of acute rejection was established, and the effect of metronomic CAP on splenic hematopoietic function and acute graft rejection was evaluated 7 d after LT. In vitro, primary CD3+ T cells were sorted from rat spleens and human peripheral blood, and co-cultured with or without 5-fluorouracil (5-FU) (active agent of CAP). The levels of ferroptosis-related proteins, ferrous ion concentration, and oxidative stress-related indicators were observed. The changes in mito-chondrial structure were observed using electron microscopy. RESULTS: With no significant myelotoxicity, metronomic CAP alleviated graft injury (Banff score 9 vs 7.333, P < 0.001), prolonged the survival time of the recipient rats (11.5 d vs 16 d, P < 0.01), and reduced the infiltration rate of CD3+ T cells in peripheral blood (6.859 vs 3.735, P < 0.001), liver graft (7.459 vs 3.432, P < 0.001), and spleen (26.92 vs 12.9, P < 0.001), thereby inhibiting acute rejection after LT. In vitro, 5-FU, an end product of CAP metabolism, induced the degradation of the ferritin heavy chain by upregulating nuclear receptor coactivator 4, which caused the accumulation of ferrous ions. It also inhibited nuclear erythroid 2 p45-related factor 2, heme oxygenase-1, and glutathione peroxidase 4, eventually leading to oxidative damage and ferroptosis of T cells. CONCLUSION: Metronomic CAP can suppress acute allograft rejection in rats by triggering CD3+ T cell ferroptosis, which makes it an effective immunosuppressive agent after LT.

Identification of circular dorsal ruffles as signal platforms for the AKT pathway in glomerular podocytes.

Circular dorsal ruffles (CDRs) are rounded membrane ruffles induced by growth factors to function as precursors of the large-scale endocytosis called macropinocytosis. In addition to their role in cellular uptake, recent research using cell line systems has shown that CDRs/macropinocytosis regulate the canonical AKT-mTORC1 growth factor signaling pathway. However, as CDRs have not been observed in tissues, their physiological relevance has remained unclear. Here, utilizing ultrahigh-resolution scanning electron microscopy, we first report that CDRs are expressed in glomerular podocytes ex vivo and in vivo, and we visually captured the transformation process to macropinocytosis. Moreover, through biochemical and imaging analyses, we show that AKT phosphorylation localized to CDRs upstream of mTORC1 activation in podocyte cell lines and isolated glomeruli. These results demonstrate the physiological role of CDRs as signal platforms for the AKT-mTORC1 pathway in glomerular podocytes at the tissue level. As mTORC1 plays critical roles in podocyte metabolism, and aberrant activation of mTORC1 triggers podocytopathies, our results strongly suggest that targeting CDR formation could represent a potential therapeutic approach for these diseases.

Translational nanomedicine potentiates immunotherapy in sarcoma by normalizing the microenvironment.

Nanocarrier-based chemo-immunotherapy has succeeded in clinical trials and understanding its effect on the tumor microenvironment could facilitate development of strategies to increase efficacy of these regimens further. NC-6300 (epirubicin micelle) demonstrates anti-tumor activity in sarcoma patients, but whether it is combinable with immune checkpoint inhibition is unclear. Here, we tested NC-6300 combined with anti-PD-L1 antibody in mouse models of osteosarcoma and fibrosarcoma. We found that sarcoma responds to NC-6300 in a dose-dependent manner, while anti-PD-L1 efficacy is potentiated even at a dose of NC-6300 less than 10% of the maximum tolerated dose. Furthermore, NC-6300 is more effective than the maximum tolerated dose of doxorubicin in increasing the tumor growth delay induced by anti-PD-L1 antibody. We investigated the mechanism of action of this combination. NC-6300 induces immunogenic cell death and its effect on the efficacy of anti-PD-L1 antibody is dependent on T cells. Also, NC-6300 normalized the tumor microenvironment (i.e., ameliorated pathophysiology towards normal phenotype) as evidenced through increased blood vessel maturity and reduced fibrosis. As a result, the combination with anti-PD-L1 antibody increased the intratumor density and proliferation of T cells. In conclusion, NC-6300 potentiates immune checkpoint inhibition in sarcoma, and normalization of the tumor microenvironment should be investigated when developing nanocarrier-based chemo-immunotherapy regimens.

Videofluorographic Analysis of Swallowing Function after Total Glossolaryngectomy.

SUMMARY: Surgeons have traditionally believed that swallowing is mainly dependent on gravity after total glossolaryngectomy. However, swallowing function after total glossolaryngectomy varies widely among patients, and a thorough analysis is lacking. The authors aimed to clarify the swallowing function after total glossolaryngectomy and determine whether it is primarily dependent on gravity. The authors retrospectively analyzed videofluorographic examinations of patients who underwent total glossolaryngectomy and free or pedicle flap reconstruction. The authors enrolled 20 patients (12 male; mean age, 61 years; age range, 43 to 89 years). All patients demonstrated constriction of the reconstructed pharynx to some degree, and no patient's ability to swallow was dependent on gravity alone. Videofluorography showed excellent barium clearance in eight patients and poor clearance in 12. All patients with excellent clearance showed strong constriction of the posterior pharyngeal wall, whereas only 8.3 percent of the patients with poor clearance showed adequate constriction, which was significantly different ( p = 0.0007). Velopharyngeal closure and lip closure also contributed significantly to excellent clearance ( p = 0.041). The shape of the reconstructed pharynx (depressed, flat, protuberant) showed no statistically significant association with excellent clearance. Contrary to previous understanding, constriction of the remnant posterior pharyngeal wall played an important role in swallowing after total glossolaryngectomy, and gravity played a secondary role. Dynamic posterior pharyngeal wall movement might result from the increased power of the pharyngeal constrictor muscle and compensate for the immobility of the transferred flap. A well-functioning pharyngeal constrictor muscle and complete velopharyngeal and lip closures can contribute to excellent barium clearance in patients after total glossolaryngectomy. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Preclinical Safety Evaluation of Intraperitoneally Administered Cu-Conjugated Anti-EGFR Antibody NCAB001 for the Early Diagnosis of Pancreatic Cancer Using PET.

Detecting tumor lesions <1 cm in size using current imaging methods remains a clinical challenge, especially in pancreatic cancer. Previously, we developed a method to identify pancreatic tumor lesions ≥3 mm using positron emission tomography (PET) with an intraperitoneally administered 64Cu-labeled anti-epidermal growth factor receptor (EGFR) antibody (64Cu-NCAB001 ipPET). Here, we conducted an extended single-dose toxicity study of 64Cu-NCAB001 ipPET in mice based on approach 1 of the current ICH M3 [R2] guideline, as our new drug formulation contains 45 µg of the antibody. We used NCAB001 labeled with stable copper isotope instead of 64Cu. The total content of size variants was approximately 6.0% throughout the study. The relative binding potency of Cu-NCAB001 to recombinant human EGFR was comparable to that of cetuximab. The general and neurological toxicities of Cu-NCAB001 ipPET at 62.5 or 625 µg/kg were assessed in mice. The no-observed-adverse-effect level of Cu-NCAB001 was 625 µg/kg, a dose approximately 1000-fold higher at the µg/kg level than the dose of 64Cu-NCAB001 in our formulation (45 µg). The size variants did not affect the safety of the formulation. Therefore, clinical studies on the efficacy of 64Cu-NCAB001 ipPET for early detection of pancreatic cancer using PET imaging can be safely conducted.

Circular dorsal ruffles disturb the growth factor-induced PI3K-AKT pathway in hepatocellular carcinoma Hep3B cells.

BACKGROUND: Circular dorsal ruffles (CDRs) are rounded membrane ruffles induced on the dorsal surfaces of cells stimulated by growth factors (GF). They can serve as signal platforms to activate AKT protein kinase. After GF stimulation, phosphatidylinositol 3-kinase (PI3K) generates phosphatidylinositol (3,4,5)-triphosphate (PIP3) in the plasma membrane. PIP3 accumulates inside CDRs, recruits AKT into the structures, and phosphorylates them (pAKT). Given the importance of the PI3K-AKT pathway in GF signaling, CDRs are likely involved in cell growth. Interestingly, some cancer cell lines express CDRs. We hypothesized that CDRs contribute to carcinogenesis by modulating the AKT pathway. In the present study, we identified CDR-expressing cancer cell lines and investigated their cellular functions. METHODS: CDR formation was examined in six cancer cell lines in response to epidermal growth factor (EGF) and insulin. The morphology of the CDRs was characterized, and the related signaling molecules were observed using confocal and scanning electron microscopy. The role of CDRs in the AKT pathway was studied using biochemical analysis. The actin inhibitor cytochalasin D (Cyto D) and the PI3K inhibitor TGX221 were used to block CDRs. RESULTS: GF treatment induced CDRs in the hepatocellular carcinoma (HCC) Hep3B cell line, but not in others, including HCC cell lines HepG2 and Huh7, and the LO2 hepatocyte cell line. Confocal microscopy and western blot analysis showed that the PI3K-PIP3-AKT pathway was activated at the CDRs and that receptor proteins were recruited to the structures. Cyto D and TGX221 completely blocked CDRs and partially attenuated GF-induced pAKT. These results indicate that CDRs regulate the receptor-mediated PI3K-AKT pathway in Hep3B cells and the existence of CDR-independent pAKT mechanisms. CONCLUSIONS: Our results showed that CDRs modulate the AKT pathway in Hep3B cells. Since CDRs were not observed in other HCC and hepatocyte cell lines, we propose that CDRs in Hep3B would determine the carcinoma characteristic of the cell by aberrantly triggering the AKT pathway. Signaling molecules involved in CDR formation are promising therapeutic targets for some types of HCC. Video abstract.

Capecitabine Regulates HSP90AB1 Expression and Induces Apoptosis via Akt/SMARCC1/AP-1/ROS Axis in T Cells.

Transplant oncology is a newly emerging discipline integrating oncology, transplant medicine, and surgery and has brought malignancy treatment into a new era via transplantation. In this context, obtaining a drug with both immunosuppressive and antitumor effects can take into account the dual needs of preventing both transplant rejection and tumor recurrence in liver transplantation patients with malignancies. Capecitabine (CAP), a classic antitumor drug, has been shown to induce reactive oxygen species (ROS) production and apoptosis in tumor cells. Meanwhile, we have demonstrated that CAP can induce ROS production and apoptosis in T cells to exert immunosuppressive effects, but its underlying molecular mechanism is still unclear. In this study, metronomic doses of CAP were administered to normal mice by gavage, and the spleen was selected for quantitative proteomic and phosphoproteomic analysis. The results showed that CAP significantly reduced the expression of HSP90AB1 and SMARCC1 in the spleen. It was subsequently confirmed that CAP also significantly reduced the expression of HSP90AB1 and SMARCC1 and increased ROS and apoptosis levels in T cells. The results of in vitro experiments showed that HSP90AB1 knockdown resulted in a significant decrease in p-Akt, SMARCC1, p-c-Fos, and p-c-Jun expression levels and a significant increase in ROS and apoptosis levels. HSP90AB1 overexpression significantly inhibited CAP-induced T cell apoptosis by increasing the p-Akt, SMARCC1, p-c-Fos, and p-c-Jun expression levels and reducing the ROS level. In conclusion, HSP90AB1 is a key target of CAP-induced T cell apoptosis via Akt/SMARCC1/AP-1/ROS axis, which provides a novel understanding of CAP-induced T cell apoptosis and lays the experimental foundation for further exploring CAP as an immunosuppressant with antitumor effects to optimize the medication regimen for transplantation patients.

HIF-1α/FOXO1 axis regulated autophagy is protective for ß cell survival under hypoxia in human islets.

ß cells suffer from hypoxia due to the rapid metabolic rate to supply insulin production. Mechanistic study of ß cell survival under hypoxia may shed light on the ß cell mass loss in type 2 diabetes mellitus (T2DM). Here, we found that the expressions of LC3 and p62/SQSTM1, two key autophagy regulators, were significantly higher in ß cells than that in non-ß endocrine cells in both non-diabetic and T2DM human pancreases, and the autophagy process was accelerated upon Cobalt Chloride (CoCl2) treatment in ex vivo cultured primary human islets. Meanwhile, CoCl2 induced the upregulation of FOXO1 in human islets, where HIF-1α played a key role. CoCl2 treatment caused the increase of ß cell apoptosis, yet inhibiting autophagy by Chloroquine or by FOXO1 knockdown further aggravated apoptosis, suggesting that FOXO1-regulated autophagy is protective for ß cell survival under hypoxia. Immunofluorescence staining showed that LC3 and p62/SQSTM1 expressions were significantly decreased in T2DM patients and negatively correlated with HbA1c, indicating that the autophagy capacity of ß cells is impaired along with the progression of the disease. Our study revealed that HIF-1α/FOXO1 regulated autophagy benefits ß cell survival under hypoxia and autophagy dysregulation may account for ß cell mass loss in T2DM. BRIEF SUMMARY: Our study revealed that HIF-1α/FOXO1 regulated autophagy benefits ß cell survival under hypoxia and autophagy dysregulation may account for ß cell mass loss in T2DM.

Evaluation of 64Cu-Labeled New Anti-EGFR Antibody NCAB001 with Intraperitoneal Injection for Early PET Diagnosis of Pancreatic Cancer in Orthotopic Tumor-Xenografted Mice and Nonhuman Primates.

OBJECTIVES: To improve the prognosis of pancreatic cancer, new imaging methods to identify tumor lesions at a size of <1 cm are urgently needed. To approach this clinical issue, we developed a new method to detect small tumor lesions in the pancreas (≥3 mm) by positron emission tomography (PET) using an intraperitoneally (ip)-administered 64Cu-labeled new anti-epidermal growth factor receptor (EGFR) antibody (encoded as NCAB001), called 64Cu-NCAB001 ipPET. METHODS: NCAB001 was manufactured under cGMP conditions and labeled with 64Cu. The radiochemical and biological properties of 64Cu-NCAB001 were evaluated. Tumor uptake of an ip-administered 64Cu-NCAB001 in mice with orthotopic pancreatic tumor xPA1-DC xenografts was also evaluated. Pharmacokinetics and radiation dosimetry were examined using PET images acquired after the ip administration of 64Cu-NCAB001 into cynomolgus monkeys with pharmacologic safety monitoring. RESULTS: Radio-chromatography, cell-binding assays, and biodistribution of 64Cu-NCAB001 in mice were identical to those of our previous data with clinically available cetuximab. Small tumor lesions in the pancreas (≥3 mm) of mice could be identified by 64Cu-NCAB001 ipPET. The ip administration of 64Cu-NCAB001 into monkeys was safely conducted using ultrasound imaging. PET images in monkeys showed that ip-administered 64Cu-NCAB001 was distributed throughout the intraperitoneal cavity for up to 6 h and cleared thereafter. Most of the radioactivity was distributed in the liver and the large intestine. The radioactivity around the pancreas became negligible 24 h after administration. The estimated human effective dose was 0.0174 mSv/MBq. CONCLUSION: Our data support the initiation of clinical trials of 64Cu-NCAB001 ipPET to transfer this promising tool for the early diagnosis of pancreatic cancers.

Capecitabine Can Induce T Cell Apoptosis: A Potential Immunosuppressive Agent With Anti-Cancer Effect.

Capecitabine (CAP) is now widely used in the comprehensive treatment of digestive system tumors. Some clinical observations have shown that CAP may have immunosuppressive effects, but there is still a lack of clear experimental verification. In this study, different doses of CAP were administered to normal mice by gavage. Our results confirmed that CAP did not cause myelosuppression in bone marrow tissue; CAP selectively reduced the proportion of T cells and the concentration of related pro-inflammatory cytokines, while it increased the concentration of anti-inflammatory cytokines. Thymidylate phosphorylase (TP) is the key enzyme for the transformation of CAP in vivo; this study confirmed that T cells express TP, but the bone marrow tissue lacks TP expression, which explains the selectivity in pharmacodynamic effects of CAP. In addition, it was confirmed that CAP can induce T cell apoptosis in vivo and in vitro. In vitro experiments showed that CAP-induced T cell apoptosis was related to TP expression, endoplasmic reticulum stress (ERS) induction, reactive oxygen species (ROS) production, and mitochondria-mediated apoptosis activation. Therefore, this study confirmed that the differential expression of TP in cells and tissues explains why CAP avoids the toxic effects of myelosuppression while inducing T cell apoptosis to exert the immunosuppressive effect. Therefore, CAP may become an immunosuppressive agent with a simultaneous anti-cancer effect, which is worthy of further studies.

Cancer of the External Auditory Canal with Extensive Osteoradionecrosis of the Skull Base after Re-Irradiation with Particle Beams: A Case Report.

Re-irradiation with X-rays and particle beams can be used to treat localized recurrence of unresectable head and neck cancer after initial irradiation therapy. However, re-irradiation therapy increases the risk of severe and late sequelae by 4-to 8-fold. It can also result in fatal outcomes, such as rupture of the carotid artery and cerebral necrosis or abscess. A 41-year-old woman was diagnosed with squamous cell carcinoma of the external auditory canal. The patient was initially treated with X-ray irradiation. However, the patient underwent re-irradiation with heavy particle beams and neutron rays for a recurrent tumor. The patient developed necrosis of the skull base involving the facial skin and temporal bone 2 months after the last session of re-irradiation therapy. The tissue in the parapharyngeal and masticatory regions also became completely necrotic, resulting in extensive exposure of the brain parenchyma. Although the patient underwent conservative and surgical treatment, necrosis of the tissue progressed, and a large part of the brain was exposed. Approximately 2.5 years later, although the brain is still exposed, the patient is alive without disease. Although the tumor had subsided and long-term survival was achieved, our patient developed serious osteoradionecrosis of the skull base with extensive brain exposure. For patients who are not candidates for surgery, re-irradiation alone is an option, albeit with poor prospects. This approach should be discussed with the patient while balancing the potential survival gain against the burden of treatment and the risk of complications.

Successful Management of a Severe Sacral Pressure Injury Penetrating to the Retroperitoneum.

INTRODUCTION: Reports of retroperitoneal infection related to a sacral pressure injury (PI) are rare, and none of the reports described the direct spread of infection through the sacrum to the retroperitoneum. The authors present, to their knowledge, the first report of a severely infected PI that showed full-thickness sacral destruction and direct retroperitoneal penetration. CASE REPORT: A 63-year-old female was referred for management of a stage 4 sacral PI complicated by a retroperitoneal abscess. The patient's comorbidities were diabetes mellitus and pemphigus foliaceus with steroid therapy-induced immunosuppression. Upon admission, the patient presented with a sacral PI producing copious purulent discharge that measured 5 cm × 3 cm. Magnetic resonance imaging revealed full-thickness sacral bone destruction and a massive retroperitoneal abscess, suggesting the sacral PI directly penetrated to the retroperitoneal space. Antibiotics were administered, and surgical debridement and sequestrectomy were performed. Negative pressure wound therapy (NPWT) with continuous saline irrigation was initiated. The patient's mesorectum was exposed within the retroperitoneal space. Therefore, a nonadhesive wound dressing was applied before placing the irrigation tube to avoid perforating the rectum. Because the patient had fragile skin secondary to long-standing pemphigus foliaceus and steroid treatment, a liquid skin protectant and hydrocolloid wound dressing were applied. The infection was successfully controlled with NPWT with saline irrigation. The patient experienced no rectal injury or skin rupture, and surgical closure was performed after 75 days. Although partial wound dehiscence occurred because of the poor condition of the skin, the resultant open wound was managed conservatively. The patient showed no retroperitoneal abscess recurrence 6 months later. CONCLUSIONS: A rare case of an intractable sacral PI complicated by retroperitoneal abscess was successfully managed in an immunocompromised patient. Notably, NPWT with saline irrigation was useful in controlling the patient's severe retroperitoneal infection.

Lymphaticovenular anastomosis for lymph vessel injury in the pelvis and groin.

BACKGROUND: Lymphatic diseases due to lymph vessel injuries in the pelvis and groin require immediate clinical attention when conventional treatments fail. We aimed to clarify the effectiveness of and indications for lymphaticovenular anastomosis (LVA) to treat these lymphatic diseases. METHODS: We retrospectively evaluated six patients who underwent LVA for lymphatic diseases due to lymph vessel injuries in the pelvis and groin. Specific pathologies included groin lymphorrhea (N = 3), chylous ascites (N = 2), and retroperitoneal lymphocele (N = 1). The maximum lymphatic fluid leakage volume was 150-2600 mL daily. Conventional treatments (compression, drainage, fasting, somatostatin administration, negative pressure wound therapy, or lymph vessel ligation) had failed to control leakage in all cases. We performed lower extremity LVAs after confirming the site of lymph vessel injury using lymphoscintigraphy. We preferentially placed LVAs in thigh sites that showed a linear pattern by indocyanine green lymphography. Postoperative lymphatic fluid leakage volume reduction was evaluated, and leakage cessation was recorded when the drainage volume approached 0 mL. RESULTS: LVA was performed at an average of 4.3 sites (range, 3-6 sites) in the thigh and 2.7 sites (range, 0-6 sites) in the lower leg. Lymphatic fluid leakage ceased in all cases after a mean of 6 days (range, 1-11 days) postoperatively. No recurrence of symptoms was observed during an average follow-up of 2.9 (range, 0.5-5.5) years. CONCLUSIONS: LVA demonstrates excellent and rapid effects. We recommend lower extremity LVA for the treatment of lymphatic diseases due to lymph vessel injuries in the pelvis and groin.

Endoplasmic reticulum-associated degradation is required for nephrin maturation and kidney glomerular filtration function.

Podocytes are key to the glomerular filtration barrier by forming a slit diaphragm between interdigitating foot processes; however, the molecular details and functional importance of protein folding and degradation in the ER remain unknown. Here, we show that the SEL1L-HRD1 protein complex of ER-associated degradation (ERAD) is required for slit diaphragm formation and glomerular filtration function. SEL1L-HRD1 ERAD is highly expressed in podocytes of both mouse and human kidneys. Mice with podocyte-specific Sel1L deficiency develop podocytopathy and severe congenital nephrotic syndrome with an impaired slit diaphragm shortly after weaning and die prematurely, with a median lifespan of approximately 3 months. We show mechanistically that nephrin, a type 1 membrane protein causally linked to congenital nephrotic syndrome, is an endogenous ERAD substrate. ERAD deficiency attenuated the maturation of nascent nephrin, leading to its retention in the ER. We also show that various autosomal-recessive nephrin disease mutants were highly unstable and broken down by SEL1L-HRD1 ERAD, which attenuated the pathogenicity of the mutants toward the WT allele. This study uncovers a critical role of SEL1L-HRD1 ERAD in glomerular filtration barrier function and provides insights into the pathogenesis associated with autosomal-recessive disease mutants.