Cancer-Derived Small Extracellular Vesicles Affect Vascular Endothelial Cells and Promote Adhesiveness of Pancreatic Cancer Cells.

OBJECTIVES: Pancreatic cancer (PC) is one of the most aggressive malignancies due to the high rate of metastasis. The mechanisms underlying metastasis need to be elucidated. Small extracellular vesicles (sEVs) mediate cell-to-cell communication, and cancer-derived sEVs contribute to the formation of premetastatic niches. The present study examined changes in adhesiveness by the internalization of PC-derived sEVs into vascular endothelial cells, and investigated the molecular mechanisms underlying metastasis. MATERIALS AND METHODS: Pancreatic cancer-derived sEVs were internalized into vascular endothelial cells, and changes in adhesiveness were evaluated. We evaluated the effects of sEVs on the formation of liver metastasis in vivo. We also assessed molecular changes in vascular endothelial cells by the internalization of PC-derived sEVs. RESULTS: The internalization of PC-derived sEVs into vascular endothelial cells promoted the adhesiveness of vascular endothelial cells and PC cells. Pancreatic cancer-derived sEVs contained high levels of transforming growth factor ß1 mRNA and acted as its transporter. Once PC-derived sEVs were internalized into vascular endothelial cells, the expression of fibronectin 1 increased on the cell surface, and the adhesiveness of vascular endothelial cells was enhanced. CONCLUSIONS: We investigated association between PC-derived sEVs and adhesiveness. Regulation of PC-derived sEVs has potential as a therapeutic modality to suppress the metastasis of PC.

Purulent nasal discharge due to gonococcal nasopharyngitis in a neonate.

Neonatal gonorrhea, caused by Neisseria gonorrhoeae, is an uncommon but important disease to prevent because its complications, such as gonococcal ophthalmia neonatorum causes blindness if untreated. Neonatal gonococcal nasopharyngitis is a rare, but important clinical manifestation to suspect gonococcal infection in a neonate. Herein we report a case of neonatal gonococcal nasopharyngitis, presented with purulent nasal discharge. A full-term male neonate without perinatal complications developed purulent eye discharge on the 7th day of life. N. gonorrhoeae was isolated from the eye discharge culture; however, he did not receive the standard regimen. Subsequently, he presented to our hospital with fever and nasal discharge on the 20th day of life. N. gonorrhoeae was also isolated from nasal discharge and nasopharyngeal swabs without any evidence of chlamydia or syphilis. He received intravenous cefotaxime until disseminated gonococcal infection was ruled out and was discharged without any sequelae. Rhinorrhea in newborns requires consideration of mother-to-child transmission of various microorganisms, not only common respiratory viruses, but also rare, serious preventable infections such as gonorrhea or syphilis. Along with the recent syphilis patients on the rise in Japan, gonorrhea is an important disease to recognize, and the incidence could increase. Clinical manifestations of neonatal gonococcal infections, including nasopharyngitis, need to be recognized to suspect the diagnosis and initiate appropriate treatment to prevent serious complications.

Roles of miR-4442 in Colorectal Cancer: Predicting Early Recurrence and Regulating Epithelial-Mesenchymal Transition.

Early recurrence in patients with colorectal cancer (CRC) is associated with a poor prognosis. We aimed to identify circulating microRNAs that are biomarkers of early CRC recurrence and elucidate their functions. We identified miR-4442 as a candidate biomarker by microRNA array analysis comparing preoperative and postoperative plasma levels in patients with CRC, with and without recurrence. The association between preoperative plasma miR-4442 levels, clinicopathological features, and recurrence-free survival was analyzed in 108 patients with CRC after curative surgery. Furthermore, cell-function analyses were performed, and the involvement of miR-4442 in regulating epithelial-mesenchymal transition (EMT) was examined. Preoperatively plasma miR-4442 levels were associated with CRC recurrence and exhibited an incremental increase with earlier recurrence dates. Moreover, miR-4442 demonstrated high sensitivity and specificity as a potential biomarker for early CRC recurrence. The expression of miR-4442 in cancer tissues of patients with metastatic liver cancer from CRC was higher than in normal liver, CRC, and normal colorectal tissues. The overexpression of miR-4442 promoted the proliferative, migratory, and invasive activities of CRC cells, decreased levels of RBMS1 and E-cadherin, and increased levels of N-cadherin and Snail1. Plasma miR-4442 is a clinically useful biomarker for predicting the early recurrence of CRC. Furthermore, miR-4442 regulates EMT in CRC by directly targeting the messenger RNA of RBMS1.

Plasma microRNA-192-5p can predict the response to neoadjuvant chemotherapy and prognosis in esophageal cancer.

Esophageal cancer (EC) is the sixth leading cause of cancer-related death worldwide. Recently, neoadjuvant chemotherapy (NAC) before curative surgery has become a standard treatment for clinical stage II or III EC patients. Some EC patients receive a complete response (CR) by NAC; thus, curative surgery may be unnecessary for such patients. MicroRNA levels in plasma have the potential to be a predictor of response to NAC. In the present study, we focused on miR-192-5p, which is highly expressed in EC tissue. The purpose was to investigate the correlations between levels of plasma miR-192-5p and the response to NAC. Furthermore, molecular functions of miR-192-5p associated with chemosensitivity were examined using EC cell lines. The levels of miR-192-5p in plasma before surgery were evaluated in 113 EC patients. Sixty-nine patients received NAC. miR-192-5p levels in the CR group were significantly higher than in the other groups (p = 0.002). The downregulation of miR-192-5p in the EC cell line inhibited sensitivity to cisplatin, and the overexpression of miR-192-5p in the EC cell line promoted sensitivity to cisplatin. miR-192-5p regulated sensitivity to cisplatin by targeting ERCC3 and ERCC4. Plasma miR-192-5p could be used as a predictor of response to chemotherapy and prognosis in EC patients.

The Role of Inflammation-associated microRNA-4257 as a Promoter of Malignancy in Colorectal Cancer.

BACKGROUND/AIM: The clinical significance ofmiR-4257 in patients with colorectal cancer (CRC) remains unclear. Here, we investigated the usefulness of measuring miR-4257 levels in the plasma and cancer tissues of patients with CRC, and the function of miR-4257 in CRC cell lines. MATERIALS AND METHODS: miR-4257 levels were measured in the plasma and cancer tissues of patients with CRC using quantitative polymerase chain reaction. The relationships between miR-4257 level and clinicopathological features were examined. Proliferation, transwell, wound healing, and adhesion assays were performed using a miR-4257 mimic and inflammatory cytokines. RESULTS: Relapse-free survival was significantly lower in patients with high miR-4257 levels in the plasma and cancer tissue (p<0.001 andp=0.016, respectively). High miR-4257 expression was an independent predictive factor for recurrence (p=0.017 and p=0.028). Addition of inflammatory cytokines to CRC and normal cell lines increased the expression of miR-4257 in the cell lines and cell culture medium. Over-expression of miR-4257 in CRC cells increased malignancy, while over-expression in normal cells increased adhesion to CRC cells. The addition of inflammatory cytokines to normal cell lines enhanced adhesion to CRC cell lines. CONCLUSION: miR-4257 level in plasma and cancer tissues is a biomarker of disease recurrence in patients with CRC. Moreover, miR-4257 promoted tumour growth and was associated with cancer-induced inflammation.

miR­4730 suppresses the progression of liver cancer by targeting the high mobility group A1 pathway.

As liver cancer (LC) is the sixth most commonly diagnosed malignancy, it is necessary to elucidate the molecular mechanisms responsible for LC progression. MicroRNAs (miRNAs/miRs) play crucial roles in tumor progression by regulating target gene expression. The present study assessed miRNA­4730 expression and function in LC. The effects of miR­4730 overexpression were examined in LC cell lines, and the target genes of miR­4730 were evaluated using microarray analysis and TargetScan data. In addition, the association between miR­4730 expression in tissue samples and the prognosis of 70 patients with LC was evaluated. miR­4730 expression was suppressed in LC tissues and cell lines. miR­4730 overexpression suppressed cell proliferation and cell cycle progression and promoted apoptosis. High mobility group A1 (HMGA1) was revealed as the direct target of miR­4730 using luciferase reporter assay, and the inhibition of downstream integrin­linked kinase (ILK) expression and Akt or glycogen synthase kinase 3ß (GSK3ß) phosphorylation was confirmed. The lower expression of miR­4730 in tissue samples was significantly associated with a worse recurrence­free survival of patients with LC. On the whole, miR­4730 suppressed tumor progression by directly targeting HMGA1 and inhibiting the ILK/Akt/GSK3ß pathway. miR­4730 thus has potential for use as a prognostic marker and may prove to be a therapeutic target for miRNA­based therapies.

Removal of small extracellular vesicles inhibits the progression of peritoneal dissemination in gastric cancer.

BACKGROUND: The prognosis of gastric cancer patients with peritoneal dissemination is extremely poor and effective treatment for peritoneal dissemination has not been established. Gastric cancer-derived small extracellular vesicles play an important role in the development of a favorable microenvironment for peritoneal metastasis and progression of peritoneal dissemination. Here, we aimed to investigate the transformation of gastric cancer cells by removing gastric cancer-derived small extracellular vesicles and to develop a novel therapy for inhibiting peritoneal dissemination. METHODS: Gastric cancer cells were cultured in medium containing gastric cancer- and peritoneal mesothelium-derived small extracellular vesicles and in medium from which small extracellular vesicles were removed by ultracentrifugation. Cell function assays were performed in vitro, and the alternations in gene expression in gastric cancer cells were analyzed. The inhibitory effect of intraperitoneal lavage on peritoneal dissemination was investigated in vivo as a method to remove gastric cancer-derived small extracellular vesicles. RESULTS: Removal of gastric cancer-derived small extracellular vesicles suppressed the proliferative and migrative abilities of gastric cancer cells and the adhesion of gastric cancer cells to peritoneal mesothelial cells. It altered the expression of several genes related to the cell cycle and epithelial-mesenchymal transition pathways of gastric cancer cells, leading to the inhibition of gastric cancer cell growth and peritoneal dissemination in vivo. CONCLUSIONS: Our study provides novel insights into a novel therapy for inhibiting the peritoneal dissemination of gastric cancer by targeting gastric cancer-derived small extracellular vesicles to improve the prognosis of gastric cancer patients with peritoneal metastasis.

Role of Extracellular High-Mobility Group Box-1 as a Therapeutic Target of Gastric Cancer.

Background: High-mobility group box-1 (HMGB1) is involved in the tumorigenesis and metastasis of various cancers. The present study investigated the roles of extracellular HMGB1 in the progression of gastric cancer (GC) and the therapeutic effects of recombinant human soluble thrombomodulin (rTM) targeting HMGB1. Methods: The effects of extracellular HMGB1 and rTM on GC cells were assessed using proliferation and Transwell assays. Their effects on local tumor growth and metastasis were evaluated using subcutaneous tumor and liver metastasis mouse models, respectively. Plasma HMGB1 concentrations in GC patients were measured using ELISA. The relationships between plasma HMGB1 concentrations and the prognosis and clinicopathological factors of patients were also investigated. Results: GC proliferation, migration, and invasion abilities were promoted by increases in extracellular HMGB1 concentrations and alleviated by rTM. In the subcutaneous tumor model, local tumor growth was promoted by the addition of rhHMGB1 and alleviated by rTM. Similar changes occurred in the liver metastasis model. Recurrence-free survival (p < 0.01) and overall survival (p = 0.01) were significantly worse in patients with high plasma HMGB1 concentrations. Conclusion: Plasma HMGB1 concentrations are a prognostic marker in GC patients. Extracellular HMGB1 promotes cancer progression and has potential as a novel treatment target in GC cells for rTM.

Soluble LR11 as a Novel Biomarker in Acute Kawasaki Disease.

BACKGROUND: Intimal smooth muscle cells (SMCs) play an important role in the vasculitis caused by Kawasaki disease (KD). Lipoprotein receptor 11 (LR11) is a member of the low-density lipoprotein receptor family, which is expressed markedly in intimal vascular SMCs and secreted in a soluble form (sLR11). sLR11 has been recently identified as a potential vascular lesion biomarker. sLR11 is reportedly elevated in patients with coronary artery lesions long after KD, but there is no description of sLR11 in acute KD. Our aim was to determine the sLR11 dynamics in acute KD and to assess its usefulness as a biomarker.Methods and Results: 106 acute KD patients and 18 age-matched afebrile controls were enrolled. KD patients were classified into the following subgroups: intravenous immunoglobulin (IVIG) responders (n=85) and non-responders (n=21). Serum sLR11 levels before IVIG therapy were higher in non-responders (median, 19.6 ng/mL; interquartile range [IQR], 13.0-24.9 ng/mL) than in controls (11.9 ng/mL, 10.4-14.9 ng/mL, P<0.01) or responders (14.3 ng/mL, 11.7-16.5 ng/mL, P<0.01). Using a cutoff of >17.5 ng/mL, non-responders to initial IVIG therapy were identified with 66.7% sensitivity and 78.8% specificity. CONCLUSIONS: sLR11 can reflect the state of acute KD and might be a biomarker for patient response to IVIG therapy.

Anterior gradient 2 regulates cancer progression in TP53­wild­type esophageal squamous cell carcinoma.

Anterior gradient 2 (AGR2) reportedly promotes tumor growth and has an unfavorable impact on survival in several cancers. However, no comprehensive functional analysis of AGR2 in esophageal squamous cell carcinoma (ESCC) has been performed. In the present study, the function and clinical significance of AGR2 were examined using ESCC cell lines and clinical samples. AGR2 was upregulated in EC tissue and ESCC cell lines. The downregulation of AGR2 suppressed cell proliferation and increased the proportion of G2/M­phase cells and phosphorylation of p53 in TP53­wild­type ESCC and osteosarcoma cells. However, these changes were not observed in TP53­mutant ESCC cells. In addition, immunohistochemistry results demonstrated that high AGR2 and low p53 expression levels in ESCC tissues were correlated with a worse prognosis. These results suggested that although AGR2 enhanced cell proliferation by inhibiting p53 phosphorylation in TP53­wild­type ESCC, the same mechanism did not regulate cell functions in TP53­mutant ESCC. Thus, AGR2 served an important role in ESCC progression and might be a useful prognostic marker in patients with TP53­wild­type ESCC.

Significance of Circular FAT1 as a Prognostic Factor and Tumor Suppressor for Esophageal Squamous Cell Carcinoma.

BACKGROUND: Circular RNA is a novel endogenous non-coding RNA with a stable loop structure, and theories for its biogenesis and usefulness as a biomarker in various cancers have been proposed. The present study investigated the significance of circular FAT1 (circFAT1) as a novel biomarker in esophageal squamous cell carcinoma (ESCC). METHOD: CircFAT1 expression levels were measured in ESCC cell lines and the effects of downregulating circFAT1 on cell migration and invasion were examined using a transwell assay. The functions of miR-548g, which will be sponged by circFAT1, were assessed. Furthermore, the expression of circFAT1 was evaluated in 51 radically resected ESCC tissue samples using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The relationships between circFAT1 expression, clinicopathological factors, and patient prognosis were analyzed. RESULTS: CircFAT1 expression levels were significantly lower in tumor tissue than in adjacent non-tumorous mucosal tissue (p = 0.01). The downregulation of circFAT1 expression promoted ESCC cell migration and invasive ability, but not proliferation. The expression of miR-548g was upregulated by the downregulation of circFAT1. The overexpression of miR-548g also promoted ESCC cell migration and invasion. Recurrence-free survival (p = 0.02) and cancer-specific survival (p = 0.04) rates were significantly higher in patients with elevated circFAT1 expression levels. CONCLUSION: The expression level of circFAT1 is a novel prognostic marker in ESCC patients. New treatment strategies may be developed using the tumor suppressive functions of circFAT1.

[A case of mature intestinal malrotation with cecal volvulus].

We report an uncommon case of an elderly patient with cecal volvulus caused by intestinal malrotation. We performed lower gastrointestinal endoscopy on an 84-year-old man with a chief complaint of abdominal distention and fever. However, emergency surgery had to be performed because intestinal perforation had occurred. The patient had cecal volvulus associated with incomplete rotation of the intestine. Subsequently, the patient developed multiple organ failure and died 2 days after the surgery. Despite its low incidence, we believe that the possibility of intestinal malrotation should be considered in elderly patients who present with abdominal distention for which the definitive diagnosis cannot be easily obtained.

[A Case of Laparoscopic Whole Layer Cholecystectomy for Elevated Lesion Suspected Biliary Cancer].

A case of attempted laparoscopic cholecystectomy for elevated lesion which was clearly early biliary cancer. Laparoscopic cholecystectomy has become popular as a minimally invasive surgical method, and is the primary choice for benign diseases. However for cases of suspected biliary cancer, open cholecystectomy, rather than laparoscopic, is recommended according to medical guidelines. The reason for this is that in cases of damage to the gallbladder, bile spillage to the abdominal cavity may occur, leading to port site recurrence and peritoneal recurrence. In addition, for invasion depth exceeding ss, or in cases of RAS cancer, the cancer may become exposed on the resected surface and remain. Hypothetically though, if the gallbladder is resected by total layer resection, RAS cancer can be removed. At this time, we performed a laparoscopic whole layer cholecystectomy for elevated lesion. We would like to report this case along with some bibliographic considerations.

A Liquid-Surface-Based Three-Axis Inclination Sensor for Measurement of Stage Tilt Motions.

In this paper a new concept of a liquid-surface-based three-axis inclination sensor for evaluation of angular error motion of a precision linear slide, which is often used in the field of precision engineering such as ultra-precision machine tools, coordinate measuring machines (CMMs) and so on, is proposed. In the liquid-surface-based three-axis inclination sensor, a reference float mounting a line scale grating having periodic line grating structures is made to float over a liquid surface, while its three-axis angular motion is measured by using an optical sensor head based on the three-axis laser autocollimation capable of measuring three-axis angular motion of the scale grating. As the first step of research, in this paper, theoretical analysis on the angular motion of the reference float about each axis has been carried out based on simplified kinematic models to evaluate the possibility of realizing the proposed concept of a three-axis inclination sensor. In addition, based on the theoretical analyses results, a prototype three-axis inclination sensor has been designed and developed. Through some basic experiments with the prototype, the possibility of simultaneous three-axis inclination measurement by the proposed concept has been verified.

[A Two-Stage Right Hemicolectomy Case in Which the First Surgery Was Laparoscopic Ileocecal Resection Based on Preoperative Diagnosis of Acute Appendicitis].

We report a case oftwo -stage right hemicolectomy in which the first surgery performed was laparoscopic ileocecal resection based on the preoperative diagnosis ofacute appendicitis. The second surgery was performed based on pathological diagnosis ofadvanced cecal cancer accompanied by appendicitis. A 49-year-old woman came to our hospital with a chief complaint of abdominal pain in the lower quadrant for 1 week. Blood test results indicated an inflammatory response, with white blood cells at 10,000/mL and C-reactive protein of1 7.5mg/dL. Abdominal computed tomography showed a swollen appendix and increased uptake in adipose tissue around the appendix. The patient was diagnosed with acute appendicitis, and emergency laparoscopic surgery was performed. Because the cecum wall was thickened and formed an inflammatory mass, ileocecal resection was performed. The pathological diagnosis was advanced cecal cancer accompanied by appendicitis, with metastasis to lymph node No. 201; thus, right hemicolectomy and D3 dissection were performed 14 days after the first surgery. No tumor was found in additional resected tissues. The final diagnosis was cecal cancer: adenocarcinoma tub1, SE, N1, M0, Stage III a. The patient received adjuvant chemotherapy with XELOX and remains relapse free. Acute appendicitis is induced by certain mechanisms that cause appendiceal obstruction. Unlike young patients, middle-aged and elderly patients rarely develop acute appendicitis because ofa tumor causing appendiceal obstruction, which often makes preoperative or perioperative diagnosis difficult. The presence of cancer, such as cecal cancer, should be considered when appendicitis is accompanied by severe inflammation in elderly patients.

Safety evaluation of substituting clopidogrel for ticlopidine in Japanese patients with ischemic stroke--Hiroshima ticlopidine, clopidogrel safe exchange trial.

BACKGROUND: Clopidogrel is sometimes substituted for ticlopidine when cerebrovascular or cardiovascular patients develop hematologic abnormalities after ticlopidine treatment. However, the adverse event rate after the substitution to clopidogrel remains undetermined. Therefore, in this study, we aimed to define the risk of adverse events after substituting clopidogrel for ticlopidine without a washout period. METHODS: We prospectively enrolled patients older than 20 years who had a history of noncardioembolic strokes, including transient ischemic attacks, were treated with ticlopidine for at least 6 months. This study was conducted from August 26, 2008, when the first patient was enrolled, to January 16, 2012, the date of the last patient examination, at 8 active stroke centers in Hiroshima, Japan. We excluded patients who had severe disabilities, evidence of cardioembolic stroke, or history of a bleeding event. Each patient received clopidogrel (either 50 mg or 75 mg) once a day in place of ticlopidine without a washout period. Follow-up exams were scheduled within 12 months after the medication substitution. The primary end point of this study was adverse events of interest, including clinically significant reduced blood cell counts, hepatic dysfunction, bleeding, and other serious side effects. RESULTS: In this study, 110 patients were enrolled and analyzed in an intent-to-treat manner (modified intent to treat). Within the scheduled follow-up periods, 9 primary end point events were observed in separate patients. The primary end point events were observed at a rate of 8.4% per year (Kaplan-Meier method). At the time of enrolment, 16 patients met the exclusion criteria, of which 8 recovered from their abnormal hematologic results to the institutional normal limit after the substitution of ticlopidine for clopidogrel (57.4% per year). CONCLUSIONS: The adverse event rates after the substitution of ticlopidine for clopidogrel is similar to the adverse event rates of patients who were initially treated with clopidogrel. The substitution of clopidogrel for ticlopidine should be considered for patients who develop hematologic abnormalities from ticlopidine treatment.

[A case of Wegener's granulomatosis presenting with tonic-clonic status epilepticus].

A 47-year-old man with a diagnosis of paranasal Wegener's granulomatosis was admitted to our hospital for generalized seizures. He had been treated with long-term predonine therapy after the initial onset of Wegener's granulomatosis. The ictal EEG showed generalized spike and wave complexes, mainly presenting in the bifrontal areas. The postictal EEG revealed periodic localized sharp discharges in the left frontal area. At the initial seizure onset, a midline multilobular mass lesion having a heterogeneous enhancement effect was detected in the lower frontal lobe on gadolinium-enhanced T1-weighted imaging (Gd T1-WI). The anterior skull base and bifrontal lobes were encroached by upward contiguous invasion of the midline mass lesion from the ethmoid sinus on Gd T1-WI. The high signal intensity lesions in the bifrontal lobes on T2- and Gd T1-WI resolved with palliative predonine therapy following methylpredonisolone pulse therapy. Recurrent generalized tonic-clonic status epilepticus was caused by the granulomatous lesion encroaching on the frontal lobe with contiguous invasion from the paranasal Wegener's granulomatosis.

[Cerebral peduncle infarction with pure dysarthria--case report].

A 82 year-old male having a long history of hypertension was admitted for dysarthria. Neurological examination revealed dysarthria with mild disturbance of left-sided soft palate elevation. No lingual palsy nor facial weakness were noted. No motor weakness in the upper and lower extremities was noted. Diffusion-weighted image and T2 weighted image revealed a small high signal lesion localized in the medial one-third of the left cerebral peduncle. There were bilateral stenotic lesions of the posterior cerebral artery at P1 portion in intracranial magnetic resonance angiography. Pure dysarthria can be caused by disruption of the supranuclear fiber of glossopharyngeal and vagal nerve nucleus in the corticobulbar tract, which can be localized in the medial portion of the cerebral peduncle.

Variability in microbial community and venting chemistry in a sediment-hosted backarc hydrothermal system: Impacts of subseafloor phase-separation.

Phase-separation and -segregation (boiling/distillation of subseafloor hydrothermal fluids) represent the primary mechanisms causing intra-field variations in vent fluid compositions. To determine whether this geochemical process affects the formation of microbial communities, we examined the microbial communities at three different vent sites located within a few tens meters of one another. In addition to chimney structures, colonization devices capturing subseafloor communities entrained by the vent fluids were studied, using culture-dependent and -independent methods. Microbiological analyses demonstrated the occurrence of distinctive microbial communities in each of the hydrothermal niches. Within a chimney structure, there was a transition from a mixed community of mesophiles and thermophiles in the exterior parts to thermophiles in the interior. Beside the transition within a chimney structure, intra-field variations in microbial communities in vent fluids were apparent. Geochemical analysis demonstrated that different vent fluids have distinctive end-member compositions as a consequence of subseafloor phase-separation and -segregation, which were designated gas-depleted, normal and gas-enriched fluids. In comparison to gas-depleted and normal fluids, gas-enriched fluids harbored more abundant chemolithoautotrophs with gaseous component-dependent energy metabolism, such as hydrogenotrophic methanogenesis. Subseafloor phase-separation and -segregation may play a key role in supplying energy and carbon sources to vent-associated chemolithoautotrophs and subvent microbial communities.