Long-Term Complete Response to Trastuzumab Deruxtecan in a Case of Unresectable Gastric Cancer.

Introduction: Trastuzumab deruxtecan (T-Dxd) has been approved for the treatment of HER2-positive gastric cancer. However, there are only a limited number of cases of gastric cancer where a long-term complete response (CR) has been maintained. Consequently, we report a case of gastric cancer in which long-term CR was maintained. Case Presentation: A woman in her late 60s underwent a gastrointestinal endoscopy, which revealed a type 2 lesion with ulceration in the lesser curvature of the vestibule, and a biopsy, which revealed an adenocarcinoma. Computed tomography (CT) revealed wall thickening of the gastric antecubital region, metastatic liver tumor, and extra-regional lymph node metastasis; a diagnosis of T4a, N3a, M1 (H, LYN), and cStage IVB (HER2 3+) was confirmed. Trastuzumab, oxaliplatin, and S-1 were administered initially. After 9 months, ascites appeared, and progressive disease was diagnosed. Paclitaxel and ramucirumab were started as second-line treatments but discontinued owing to neutropenia and increasing ascites. Third-line treatment with T-Dxd was initiated, and 11 months later, CT showed the disappearance of metastases. Even after 31 months, the CR was maintained. Conclusion: To the best of our knowledge, this is one of the few cases in which long-term CR was maintained with third-line T-Dxd treatment. Treatment strategies for patients with gastric cancer to achieve long-term CR require careful consideration.

Lysyl Oxidase Regulates Epithelial Differentiation and Barrier Integrity in Eosinophilic Esophagitis.

BACKGROUND & AIMS: Epithelial disruption in eosinophilic esophagitis (EoE) encompasses both impaired differentiation and diminished barrier integrity. We have shown that lysyl oxidase (LOX), a collagen cross-linking enzyme, is up-regulated in the esophageal epithelium in EoE. However, the functional roles of LOX in the esophageal epithelium remains unknown. METHODS: We investigated roles for LOX in the human esophageal epithelium using 3-dimensional organoid and air-liquid interface cultures stimulated with interleukin (IL)13 to recapitulate the EoE inflammatory milieu, followed by single-cell RNA sequencing, quantitative reverse-transcription polymerase chain reaction, Western blot, histology, and functional analyses of barrier integrity. RESULTS: Single-cell RNA sequencing analysis on patient-derived organoids revealed that LOX was induced by IL13 in differentiated cells. LOX-overexpressing organoids showed suppressed basal and up-regulated differentiation markers. In addition, LOX overexpression enhanced junctional protein genes and transepithelial electrical resistance. LOX overexpression restored the impaired differentiation and barrier function, including in the setting of IL13 stimulation. Transcriptome analyses on LOX-overexpressing organoids identified an enriched bone morphogenetic protein (BMP) signaling pathway compared with wild-type organoids. In particular, LOX overexpression increased BMP2 and decreased the BMP antagonist follistatin. Finally, we found that BMP2 treatment restored the balance of basal and differentiated cells. CONCLUSIONS: Our data support a model whereby LOX exhibits noncanonical roles as a signaling molecule important for epithelial homeostasis in the setting of inflammation via activation of the BMP pathway in the esophagus. The LOX/BMP axis may be integral in esophageal epithelial differentiation and a promising target for future therapies.

Cancer Stem Cells Persist Despite Cellular Damage, Emergence of the Refractory Cell Population.

PURPOSE: Cancer stem cells (CSCs) are responsible for chemotherapy resistance and have unique properties that protect them from chemotherapy. Investigating CSCs may help to identify the population that is more resistant to treatments, leading to recurrence. We evaluated persisting CSCs, emerging after chemotherapy that cause tumor recurrence. METHODS: Using human colorectal cancer organoids prepared from surgical specimens, we looked at changes in CSCs, the emergence and changes in the original population, which single-cell analysis identified. RESULTS: With regards to changes in cancer stem cell markers, CD44 showed low levels after 5-fluorouracil administration. Once the CD44-ve population was sorted and cultured, the CD44+ve population gradually emerged, and the CD44-ve population decreased. Compared with the CD44-ve population of an organoid parent, the CD44-ve population proliferated after chemotherapeutic agent stimulation. The CD44-ve population was derived from the CD44+ve population before chemotherapeutic agents. In addition, when the CD44 variants were evaluated, the CD44v9 population remained. In single-cell analysis, we found that POU5F1 was highly expressed in the CD44low population. Velocity analysis showed that the CD44-ve population was induced after chemotherapy and expressed POU5F1. POU5F1-EGFP-Casp9 transfected organoids resulted in the appearance of a CD44-ve population after administration of a chemotherapeutic reagent. Both in vivo and in vitro, the dimerizer administration inhibited tumor growth significantly. CONCLUSIONS: POU5F1 is involved in chemotherapy resistance in relation to stemness. For the treatment against refractory tumors, such as the recurrence after chemotherapy, the treatment should target the emerging specific population such as CD44 (or CD44v9) and proliferative cancer cells.

A rare case of multiple port site incisional hernias repaired by laparoscopy-assisted intraperitoneal onlay mesh: A case report.

INTRODUCTION: Port site herniation is a frequent complication of abdominal surgery, yet treatment strategies for multiple port site hernias are often difficult and case reports are rare. PRESENTATION OF CASE: A 72-year-old woman, with a history of multiple abdominal surgeries, underwent laparoscopic surgery for rectal prolapse four years prior. Three 12 mm ports were inserted into the umbilical region, right upper quadrant and right lower abdomen, subsequently, incisional hernias developed at all three sites. In addition, an incisional hernia developed in the lower abdomen, for a total of four incisional hernias. She was taking apixaban for atrial fibrillation, and since the standard surgical method of placing the mesh in the extraperitoneal space was judged to be high risk for postoperative bleeding and hematoma formation, we performed a laparoscopy-assisted intraperitoneal onlay mesh repair (IPOM). DISCUSSION: The key points of the surgery performed are: Laparoscopic surgery was initiated with a small incision in the umbilical region, using two 5 mm ports because we reasoned that using a 12 mm port could cause a new hernia. In the lateral hernia repair, a mesh was placed in the preperitoneal space on the dorsal side of the hernia, the mesh was sutured to the peritoneum because tucking cannot be performed if nerves are present on the dorsal aspect. The medial hernia was repaired by IPOM via a small laparotomy incision. CONCLUSION: For multiple incisional hernias, it is necessary to consider appropriate repair methods for each site.

Surgical strategies for localized colorectal amyloidosis.

BACKGROUND: Localized colorectal amyloidosis has a good prognosis, but cases involving bleeding or perforation may require surgery. However, there are few case reports discussing the differences in the surgical strategy between the segmental and pan-colon types. CASE PRESENTATION: A 69-year-old woman with a history of abdominal pain and melena was diagnosed with amyloidosis localized in the sigmoid colon by colonoscopy. Since preoperative imaging and intraoperative findings could not rule out malignancy, we performed laparoscopic sigmoid colectomy with lymph-node dissection. Histopathological examination and immunohistochemical staining revealed a diagnosis of AL amyloidosis (λ type). We diagnosed localized segmental gastrointestinal amyloidosis, because there was no amyloid protein in the margins, and the tumor was localized. There were no malignant findings. CONCLUSIONS: Unlike systemic amyloidosis, localized amyloidosis has a favorable prognosis. Localized colorectal amyloidosis can be classified into the segmental type, in which amyloid protein is deposited locally, and the pan-colon type, in which amyloid protein is deposited extensively in the colon. Amyloid protein causes ischemia due to vascular deposition, weakening of the intestinal wall due to muscle layer deposition, and decreased peristalsis due to nerve plexus deposition. No amyloid protein should remain outside the resection area. The pan-colon type is often reported to cause complications such as anastomotic leakage, and primary anastomosis should be avoided. On the other hand, if there is no contamination or tumor remnants in the margin, the segmental type may be considered for primary anastomosis.

Lysyl oxidase regulates epithelial differentiation and barrier integrity in eosinophilic esophagitis.

Background & Aims: Epithelial disruption in eosinophilic esophagitis (EoE) encompasses both impaired differentiation and diminished barrier integrity. We have shown that lysyl oxidase (LOX), a collagen cross-linking enzyme, is upregulated in the esophageal epithelium in EoE. However, the functional roles of LOX in the esophageal epithelium remains unknown. Methods: We investigated roles for LOX in the human esophageal epithelium using 3-dimensional organoid and air-liquid interface cultures stimulated with interleukin (IL)-13 to recapitulate the EoE inflammatory milieu, followed by single-cell RNA sequencing, quantitative reverse transcription-polymerase chain reaction, western blot, histology, and functional analyses of barrier integrity. Results: Single-cell RNA sequencing analysis on patient-derived organoids revealed that LOX was induced by IL-13 in differentiated cells. LOX-overexpressing organoids demonstrated suppressed basal and upregulated differentiation markers. Additionally, LOX overexpression enhanced junctional protein genes and transepithelial electrical resistance. LOX overexpression restored the impaired differentiation and barrier function, including in the setting of IL-13 stimulation. Transcriptome analyses on LOX-overexpressing organoids identified enriched bone morphogenetic protein (BMP) signaling pathway compared to wild type organoids. Particularly, LOX overexpression increased BMP2 and decreased BMP antagonist follistatin. Finally, we found that BMP2 treatment restored the balance of basal and differentiated cells. Conclusions: Our data support a model whereby LOX exhibits non-canonical roles as a signaling molecule important for epithelial homeostasis in the setting of inflammation via activation of BMP pathway in esophagus. The LOX/BMP axis may be integral in esophageal epithelial differentiation and a promising target for future therapies.

Gastric volvulus associated with shrinkage of a gastrointestinal stromal tumor by neoadjuvant imatinib: a case report.

BACKGROUND: During neoadjuvant chemotherapy for giant gastrointestinal stromal tumors, changes in gastrointestinal stromal tumor size are rarely associated with events such as perforation and bleeding that require emergency surgery. Moreover, it is very rare for gastrointestinal stromal tumors to shrink and become mobile, resulting in gastric volvulus. Herein, we report a case of gastrointestinal stromal tumor shrinkage during neoadjuvant imatinib treatment, resulting in gastric volvulus that required surgery. To the best of our knowledge, this is the first reported occurrence of gastric volvulus during neoadjuvant imatinib treatment for a giant gastrointestinal stromal tumor. CASE PRESENTATION: A 58-year-old Japanese woman who was diagnosed with a giant gastric gastrointestinal stromal tumor and administered neoadjuvant imatinib presented to our hospital with complaints of abdominal pain and retching. Enhanced computed tomography revealed that the gastrointestinal stromal tumor had shrunk and shifted in position, and the stomach had organoaxially twisted. Accordingly, the patient was diagnosed with gastric volvulus caused by a gastric gastrointestinal stromal tumor. Conservative treatment did not improve the volvulus; hence, laparotomy was performed. The tumor developed from the lesser curvature of the stomach and caused rotation of the gastric body. The local gastric wall was resected. Histopathological examination confirmed the diagnosis of gastrointestinal stromal tumor. The patient received adjuvant imatinib for 3 years and has been alive for 5 years without recurrence. CONCLUSIONS: Gastric volvulus can be caused by the laxity of the ligaments that hold the stomach and gastric ptosis or esophageal hernia and diaphragmatic hernia; therefore, gastric gastrointestinal stromal tumors rarely cause gastric volvulus. However, a risk of torsion exists if the gastrointestinal stromal tumor develops extramural to lesser curvature and attains a certain size.

CD73+ Epithelial Progenitor Cells That Contribute to Homeostasis and Renewal Are Depleted in Eosinophilic Esophagitis.

BACKGROUND & AIMS: Although basal cell hyperplasia is a histologic hallmark of eosinophilic esophagitis (EoE), little is known about the capabilities of epithelial renewal and differentiation in the EoE inflammatory milieu. In murine esophageal epithelium, there are self-renewing and slowly proliferating basal stem-like cells characterized by concurrent expression of CD73 (5'-nucleotidase ecto) and CD104 (integrin ß4). Here, we investigated CD73+CD104+ cells within the basal population of human esophageal epithelium and clarified the biological significance of these cells in the EoE epithelium. METHODS: We performed flow cytometry on esophageal biopsy samples from EoE and non-EoE patients to determine the quantity of CD73+CD104+ cells in the epithelium. Simulating the EoE milieu we stimulated primary patient-derived and immortalized cell line-derived esophageal organoids with interleukin (IL)4 and IL13 and analyzed by flow cytometry, immunohistochemistry, and quantitative reverse-transcription polymerase chain reaction. We performed single-cell RNA sequencing on primary organoids in the setting of IL13 stimulation and evaluated the CD73+CD104+ population. We performed fluorescent-activated cell sorting to purify CD73+CD104+ and CD73- CD104+ populations and seeded these groups in organoid culture to evaluate the organoid formation rate and organoid size. We used RNA interference to knock down CD73 in esophageal organoids to evaluate organoid formation rates and size. We evaluated the effects of signal transducer and activator of transcription 6 (STAT6) signaling inhibition by RNA interference, a STAT6 inhibitor, AS1517499, as well as the proton pump inhibitor omeprazole. RESULTS: EoE patients showed decreased epithelial CD73+CD104+ cell content. IL4 and IL13 stimulation depleted this population in 3-dimensional organoids with a recapitulation of basal cell hyperplasia as corroborated by single-cell RNA sequencing of the organoids, which suggests depletion of CD73+CD104+ cells. The CD73+CD104+ population had enhanced organoid formation compared with the CD73-CD104+ population. Similarly, knock-down of CD73 resulted in decreased organoid formation rate. Genetic and pharmacologic inhibition of STAT6 prevented T helper 2 cytokine-induced depletion of CD73+CD104+ cells. Lastly, omeprazole treatment prevented the effects of IL4 and IL13 on the CD73+CD104+ population. CONCLUSIONS: This study addressed the role of CD73+CD104+ cells in epithelial renewal and homeostasis in the context of EoE. The depletion of the CD73+CD104+ self-renewal population by helper T cell 2 cytokines in EoE milieu may be perpetuating epithelial injury. Future therapies targeting epithelial restitution in EoE could decrease the need for immune modulation and steroid therapy.

Current treatment strategies and future perspectives for gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that originate from the gastrointestinal tract, mostly from the stomach. GISTs are derived from the myenteric interstitial cells of Cajal and are caused by several mutations in the c-kit and platelet-derived growth factor receptor genes. Clinically, GISTs are detected by endoscopic and imaging findings and are diagnosed by immunostaining. Surgery is the first line of treatment, and if the tumor is relatively small, minimally invasive surgery such as laparoscopy is performed. In recent years, neoadjuvant therapy has been administered to patients with GISTs that are suspected of having a large size or infiltration to other organs. Postoperative adjuvant imatinib is the standard therapy for high-risk GISTs. It is important to assess the risk of recurrence after GIST resection. However, the effect of tyrosine kinase inhibitor use will vary by the mutation of c-kit genes and the site of mutation. Furthermore, information regarding gene mutation is indispensable when considering the treatment policy for recurrent GISTs. This article reviews the clinicopathological characteristics of GISTs along with the minimally invasive and multidisciplinary treatment options available for these tumors. The future perspectives for diagnostic and treatment approaches for these tumors have also been discussed.

Laparoscopy-assisted repair with Ventralex ST Hernia Patch for a small subcostal hernia: A case report.

A 55-year-old woman with a history of right hepatic lobectomy via a Benz incision presented for evaluation of a new abdominal bulge in the right upper quadrant. We diagnosed an incisional hernia, but because we could neither reduce the hernia contents nor locate the orifice, we performed a laparoscopic evaluation. Laparoscopy revealed subcostal herniation of the greater omentum via a 2-cm defect on the caudal side of the right ribs, which we repaired using a Ventralex ST Hernia Patch. Laparoscopic placement of this mesh with straps allowed for reliable deployment, fixation, and confirmation of defect closure, including the cranial aspect-often a major challenge in subcostal hernia repair.

The meiosis-specific cohesin component stromal antigen 3 promotes cell migration and chemotherapeutic resistance in colorectal cancer.

Chromosome instability is one of the hallmarks of cancer. Stromal antigen (STAG) 3 is a core component of the meiosis-specific cohesin complex, which regulates sister chromatid cohesion. Although aberrantly activated genes encoding the cohesin complex have been identified in cancers, little is known about the role of STAG3 in colorectal cancer (CRC). Here, we evaluated the prognostic impact and role of STAG3 in CRC. Analysis of 172 CRC surgical specimens revealed that high STAG3 expression was associated with poor prognosis. STAG3 knockdown inhibited cell migration and increased drug sensitivity to oxaliplatin, 5-fluorouracil, irinotecan hydrochloride hydrate, and BRAF inhibitor in CRC cell lines. The enhanced drug sensitivity was also confirmed in a human organoid established from a CRC specimen. Moreover, suppression of STAG3 increased γH2AX foci. Particularly, in BRAF-mutant CRC cells, STAG3 silencing suppressed the expression of snail family transcriptional repressor 1 and phosphorylation of extracellular signal-regulated kinase via upregulation of dual-specificity phosphatase 6. Our findings suggest that STAG3 is related to poor clinical outcomes and promotes metastasis and chemotherapeutic resistance in CRC. STAG3 may be a novel prognostic marker and potential therapeutic target for CRC.

Laparoscopic transabdominal preperitoneal repair for recurrent groin hernia after failed anterior-posterior repair.

INTRODUCTION: The International Guidelines for Groin Hernia Management recommends an anterior repair after a failed posterior repair, and laparoscopic repair after a failed anterior tissue repair or Lichtenstein repair. However, there are not enough studies to guide decision-making for patients with recurrent hernia patients after combined anterior-posterior repair. We investigate the safety and usefulness of transabdominal preperitoneal repair (TAPP) for recurrent hernia patients after failed anterior-posterior repair. METHODS: We conducted a retrospective analysis of 13 consecutive patients with recurrent groin hernia who underwent TAPP after prior anterior preperitoneal mesh repair (that created anterior and posterior scarring) between September 2013 and October 2018. The control group comprised 45 patients who underwent TAPP for recurrent hernia after anterior repair (43 nonmesh repairs and two Lichtenstein repairs). RESULTS: There were no intraoperative complications, and chronic pain was not reported by the patients with prior anterior preperitoneal mesh repair. The mean operative time was 113 ± 31.3 minutes, and the mean postoperative stay was 1.62 ± 0.87 days. The Wong-Baker FACES rating scale score for pain on postoperative day 1 was 1.91 ± 1.5; on postoperative day 7, the score was 1.0 ± 0.89. None of these findings was significantly different from the findings in patients who had a prior anterior repair. A single patient experienced a further recurrence and underwent repeat TAPP. CONCLUSIONS: The use of TAPP after failed combined anterior-posterior mesh repair may be feasible and safe for recurrent groin hernia. Further study is needed to determine long-term outcomes.

A case of diaphragmatic hernia incarceration after a heart transplant operation.

We report a case of a diaphragmatic hernia after a heart transplant operation. A 43-year-old woman, who underwent orthotropic heart transplantation for hypertrophic cadiomyopathy two year earlier, presented with vomiting and epigastric pain. A computed tomography scan showed that the stomach and transverse colon were dislocated in the left thoracic cavity. We diagnosed left diaphragmatic hernia incarceration and performed laparoscopic repair of the diaphragmatic hernia. A 12 × 8 cm diaphragmatic defect was found intraoperatively on the ventrolateral aspect of the left diaphragm, and the stomach with volvulus had herniated into the thorax through the defect. The hernia was considered to be iatrogenic. The diaphragmatic defect was large, and the diaphragm was thinning. We closed the defect by mesh repair. Laparoscopic mesh repair of the diaphragmatic hernia could be performed safely and with minimal invasiveness.

Solitary peritoneal metastasis of gastrointestinal stromal tumor: A case report.

BACKGROUND: A gastrointestinal stromal tumor (GIST) is a mesenchymal tumor of the gastrointestinal tract that is most commonly found in the stomach. Recurrence of GISTs mostly occurs in the liver or peritoneum, and in most cases, multiple metastases occur. As a solitary peritoneal metastasis is rare, an appropriate treatment strategy has not been established. Here, we report a case of solitary peritoneal metastasis after complete resection of gastric GIST. CASE SUMMARY: A 76-year-old woman was diagnosed with stomach GIST and underwent laparoscopic local resection using the CLEAN-NET method. As the recurrence risk was intermediate, adjuvant imatinib therapy was not administered. Two years after surgery, routine computed tomography revealed an abdominal mass between the dorsal side of the right hepatic lobe and right kidney. Other imaging tests did not reveal any abnormalities. Laparoscopic observation showed that the tumor was located at the retroperitoneum, and intraperitoneal dissemination was not found. Therefore, we performed laparoscopic tumor resection. Immunohistochemically, the tumor was positive for c-kit and CD34 and had a relatively high mitotic index and MIB-1 Labeling index. We administered adjuvant imatinib therapy. There was no evidence of recurrence 3 years after the operation. CONCLUSION: This is the first reported case of a solitary recurrence of GIST in the peritoneum treated with complete laparoscopic resection.

Dipeptidyl Peptidase 9 Increases Chemoresistance and is an Indicator of Poor Prognosis in Colorectal Cancer.

BACKGROUND: In recent years, systemic chemotherapy has significantly improved the prognosis of metastatic colorectal cancer (CRC); however, different patients have different responses to chemotherapeutics. METHODS: Dipeptidyl peptidase 9 (DPP9) is an enzyme in the dipeptidyl peptidase IV family that has been reported to increase drug sensitivity in acute myeloid leukemia. In this study, we examined the relationship between DPP9 expression and the prognosis of patients with CRC, as well as the role of DPP9 in anticancer drug resistance. Moreover, the effects of the DPP9 inhibitors talabostat and vildagliptin in CRC cell lines and primary cultured cells were assessed. RESULTS: High expression of DPP9 was associated with worse prognosis in 196 patients with CRC. Cell viability was markedly inhibited in CRC cell lines transfected with DPP9 small interfering RNA or small hairpin RNA. Talabostat suppressed proliferation in CRC cell lines and primary cultured cells, and increased their sensitivity to chemotherapy. Vildagliptin, a DPP family inhibitor currently administered for diabetes, also increased the sensitivity of CRC cells to anticancer drugs. CONCLUSION: DPP9 was a poor prognostic factor for CRC and could be a new therapeutic target, while vildagliptin could be used as a repositioned drug for CRC treatment.

The Geriatric Nutritional Risk Index predicts postoperative complications and prognosis in elderly patients with colorectal cancer after curative surgery.

Malnutrition has been considered to be associated with the prognosis of cancer. The Geriatric Nutritional Risk Index (GNRI), based on serum albumin levels, present body weight, and ideal body weight, is a simple screening tool to predict the risk of nutrition-related morbidity and mortality in elderly patients. We aimed to evaluate whether preoperative GNRI was associated with postoperative complications and prognosis in elderly patients with colorectal cancer (CRC). We retrospectively enrolled 313 CRC patients aged ≥65 years after curative surgery and classified them into an all-risk GNRI (≤98) group and a no-risk GNRI (>98) group. Kaplan-Meier analysis showed overall survival was significantly worse in the all-risk GNRI group than in the no-risk GNRI group (P = 0.009). Multivariable analyses showed low GNRI (≤98) was an independent risk factor for postoperative complications (P = 0.048) and overall survival (P = 0.001) in the patients. Among the complications, the incidence of surgical site infection, in particular, was significantly higher in the all-risk GNRI group (P = 0.008). In conclusion, low preoperative GNRI (≤98) was associated with increased postoperative complications and poor prognosis. Preoperative GNRI can be used as an identifier for potential high-risk group of morbidity and mortality in elderly CRC patients.

Fibrodysplasia ossificans progressiva with two emergency laparotomies: A case report.

INTRODUCTION: Fibrodysplasia ossificans progressiva (FOP) is a disorder causing progressive heterotopic ossification of muscles, tendons, and ligaments. Invasive procedures such as surgery should be avoided, because physical stimulation causes heterotopic ossification. PRESENTATION OF CASE: A 40-year-old Japanese man with FOP was transported to our hospital with sudden abdominal pain. Emergency surgery was performed because a computed tomography scan showed the presence of intraabdominal free air. We diagnosed peritonitis due to perforation of Meckel's diverticulum and performed a small intestinal resection. The day after surgery, airway obstruction was recognized, and tracheostomy was required. Six months after surgery, a strangulated small bowel obstruction developed, and a second laparotomy was performed. As the patient continued to have difficulty swallowing, we constructed a gastrostomy at the time of the second surgery. He was discharged with no complications. DISCUSSION: Ossification of the abdominal incision wound due to surgical invasion was suspected, but it did not occur in the short term. CONCLUSION: Two laparotomies could be performed safely in a patient with FOP.

In vitro Assay for Bacterial Membrane Protein Integration into Proteoliposomes.

It is important to experimentally determine how membrane proteins are integrated into biomembranes to unveil the roles of the integration factors, and to understand the functions and structures of membrane proteins. We have developed a reconstitution system for membrane protein integration in E. coli using purified factors, in which the integration reaction in vivo is highly reproducible. This system enabled not only analysis of membrane-embedded factors including glycolipid MPIase, but also elucidation of the detailed mechanisms underlying membrane protein integration. Using the system, the integration of membrane proteins can be evaluated in vitro through a protease-protection assay. We report here how to prepare (proteo)liposomes and to determine the activities of membrane protein integration.

Laparoscopic plug removal for chronic pain after inguinal hernia repair using the plug-and-patch technique: A case report.

INTRODUCTION: The use of tension-free mesh repair techniques for inguinal hernias has led to uniformly low recurrence rates. The main associated morbidity is chronic postoperative inguinal pain. Mesh removal and triple neurectomy is the indicated procedure; there is insufficient evidence to support mesh removal alone without neurectomy in patients with chronic postoperative inguinal pain. PRESENTATION OF CASE: A 76-year-old man previously underwent repair of a right inguinal direct hernia using the plug-and-patch technique. Two years later, he experienced groin pain requiring the use of pain medication. Five years after surgery, he expressed the desire to remove the mesh because of chronic pain, rated 8 out of 10 on a numeric rating scale. We suspected that he was experiencing nociceptive pain caused by a plug meshoma, so we performed a laparoscopic plug extraction. His inguinal pain improved to 2 out of 10 on the second postoperative day, and he stopped taking pain medication by 10 months after surgery. DISCUSSION: The laparoscopic approach to plug removal is safe and simple. We successfully avoided causing new-onset pain by not using a groin incision to remove the mesh plug. CONCLUSION: Laparoscopic plug removal for nociceptive pain due to a plug meshoma is effective. However, since there is insufficient evidence to recommend mesh removal without triple neurectomy, informed consent and further consideration of techniques and diagnostic methods are needed.

The bacterial protein YidC accelerates MPIase-dependent integration of membrane proteins.

Bacterial membrane proteins are integrated into membranes through the concerted activities of a series of integration factors, including membrane protein integrase (MPIase). However, how MPIase activity is complemented by other integration factors during membrane protein integration is incompletely understood. Here, using inverted inner-membrane vesicle and reconstituted (proteo)liposome preparations from Escherichia coli cells, along with membrane protein integration assays and the PURE system to produce membrane proteins, we found that anti-MPIase IgG inhibits the integration of both the Sec-independent substrate 3L-Pf3 coat and the Sec-dependent substrate MtlA into E. coli membrane vesicles. MPIase-depleted membrane vesicles lacked both 3L-Pf3 coat and MtlA integration, indicating that MPIase is involved in the integration of both proteins. We developed a reconstitution system in which disordered spontaneous integration was precluded, which revealed that SecYEG, YidC, or both, are not sufficient for Sec-dependent and -independent integration. Although YidC had no effect on MPIase-dependent integration of Sec-independent substrates in the conventional assay system, YidC significantly accelerated the integration when the substrate amounts were increased in our PURE system-based assay. Similar acceleration by YidC was observed for MtlA integration. YidC mutants with amino acid substitutions in the hydrophilic cavity inside the membrane were defective in the acceleration of the Sec-independent integration. Of note, MPIase was up-regulated upon YidC depletion. These results indicate that YidC accelerates the MPIase-dependent integration of membrane proteins, suggesting that MPIase and YidC function sequentially and cooperatively during the catalytic cycle of membrane protein integration.