Erythrocytes Display Metabolic Changes in High-Altitude Polycythemia.

Qile, Muge, Qiying Xu, Yi Ye, Huifang Liu, Drolma Gomchok, Juanli Liu, Tana Wuren, and Ri-Li Ge. Erythrocytes display metabolic changes in high-altitude polycythemia. High Alt Med Biol. 24:104-109, 2023. Background: Sphingosine-1-phosphate (S1P) levels are increased after acute exposure to high altitude; however, whether this effect is observed in chronic high-altitude hypoxia is unknown. Methods: We studied erythrocyte S1P levels in 13 subjects with high-altitude polycythemia (HAPC) and 13 control subjects and also used a mouse model of HAPC. HAPC subjects lived in Maduo (4,300 m altitude) for 10 years, whereas control subjects lived permanently in Xining (2,260 m). The mouse model of HAPC was established by stimulating an altitude of 5,000 m in a hypobaric chamber for 30 days. Hematology and S1P, CD73, 2,3-bisphosphoglycerate (2,3-BPG), and reticulocyte levels were measured. Results: The hemoglobin concentration and number of red blood cells were significantly elevated in human and mouse HAPC groups. Blood S1P levels in HAPC subjects and mice were higher than those in control groups (p < 0.05 and p < 0.001, respectively). 2,3-BPG and CD73 levels in HAPC subjects were significantly higher than those in control subjects (p < 0.05). No significant changes in reticulocyte levels were observed. Conclusions: The critical altitude-induced metabolic changes such as S1P retained high levels even after prolonged exposure, and it may inspire future research into therapeutic strategies for hypoxia-associated illnesses.

Inflammation and immunity in the pathogenesis of hypoxic pulmonary hypertension.

Hypoxic pulmonary hypertension (HPH) is a complicated vascular disorder characterized by diverse mechanisms that lead to elevated blood pressure in pulmonary circulation. Recent evidence indicates that HPH is not simply a pathological syndrome but is instead a complex lesion of cellular metabolism, inflammation, and proliferation driven by the reprogramming of gene expression patterns. One of the key mechanisms underlying HPH is hypoxia, which drives immune/inflammation to mediate complex vascular homeostasis that collaboratively controls vascular remodeling in the lungs. This is caused by the prolonged infiltration of immune cells and an increase in several pro-inflammatory factors, which ultimately leads to immune dysregulation. Hypoxia has been associated with metabolic reprogramming, immunological dysregulation, and adverse pulmonary vascular remodeling in preclinical studies. Many animal models have been developed to mimic HPH; however, many of them do not accurately represent the human disease state and may not be suitable for testing new therapeutic strategies. The scientific understanding of HPH is rapidly evolving, and recent efforts have focused on understanding the complex interplay among hypoxia, inflammation, and cellular metabolism in the development of this disease. Through continued research and the development of more sophisticated animal models, it is hoped that we will be able to gain a deeper understanding of the underlying mechanisms of HPH and implement more effective therapies for this debilitating disease.

Apoptosis is one cause of thrombocytopenia in patients with high-altitude polycythemia.

High-altitude polycythemia (HAPC) can occur in individuals who are intolerant to high-altitude hypoxia. In patients with HAPC, erythrocytosis is often accompanied by a decrease in platelet count. Chronic hypoxia can increase the incidence of arteriovenous thrombosis and the risk of bleeding during antithrombotic treatment due to thrombocytopenia; therefore, understanding the cause of thrombocytopenia can reduce the risk of treatment-related bleeding. In this study, we examined platelet production and apoptosis to understand the cause of thrombocytopenia in patients with HAPC. The classification of myeloid-derived megakaryocytes (MKs) in HAPC patients was mainly granular MKs rather than mature MKs, suggesting impaired differentiation and maturation. However, the total number of MKs and newly generated reticulated platelets in the peripheral blood increased, indicating sufficient platelet generation in HAPC thrombocytopenia. Increased platelet apoptosis may be one of the causes of thrombocytopenia. Platelet activation and GP1bα pathway activation induced by thrombin and von Willebrand factor can lead to platelet apoptosis. Platelet production was not reduced in patients with HAPC, whereas platelet apoptosis was associated with thrombocytopenia. These findings provide a rationale for considering the bleeding risk in HAPC patient while treating thrombotic diseases.

What is the context?Platelets are essential in the process of blood clotting; hence, low platelet count increases the risk of bleeding. Thrombocytopenia is present in patients with high-altitude polycythemiaHypoxia can lead to platelet activation and increase in procoagulant factors, while at the same time increase the risk of thrombosis due to erythrocytosis and blood stasis.Antithrombotic therapy should be administered when thrombosis occurs in patients with high altitude polycythemia; however, due to the low platelet count, risk of bleeding must be considered.What is new?In this study, we found that platelet production was not decreased in patients with high-altitude polycythemia.One cause of thrombocytopenia is apoptosis, which is associated with platelet activation, especially GP1bα activation.Inhibition of GP1bα binding to ligand decreased the level of platelet apoptosis.What is the impact?This study provides novel insights into antithrombotic therapy for patients with high-altitude polycythemia complicated by thrombosis.Thrombocytopenia is associated with excessive apoptosis.Interfering with GP1bα targets may have a dual benefit, both in inhibiting thrombosis and avoiding thrombocytopenia.

Dynamic changes in myeloid-derived suppressor cells during the menstrual cycle: A pilot study.

Various studies have described the roles of myeloid-derived suppressor cells (MDSCs) in pathological conditions, but relatively few have described them under normal physiological conditions. Accumulation of MDSCs is important creating an anti-inflammation environment, which is essential for fertilized egg implantation. This study was designed to record the dynamic changes in MDSC-like cells composition during the menstrual period (MP) and ovulation period (OP) in healthy volunteers over the course of a single menstrual cycle to explore the association between MDSCs and the menstrual cycle under normal physiological conditions. The ratio of MDSC-like cells was higher in MP samples, whereas the activity of Arg-1 was higher during the OP window. There was a negative correlation between the ratio of MDSC-like cells and the percentage of lymphocytes and a positive correlation between MDSC-like cells and prostaglandin E2 (PGE2). Furthermore, regular changes in the ratio and function of MDSC-like cells in the peripheral blood were observed during menstruation, all of which corresponded to the cycle stage. During menstruation, MDSCs may promote endometrial repair, whereas they promote pregnancy during the OP. These findings may help to better understand the pathophysiology of pregnancy-related complications and lay a foundation for improving perinatal outcomes.

Identification of a miRNA-mRNA Regulatory Networks in Placental Tissue Associated With Tibetan High Altitude Adaptation.

The Tibetan population has lived and successfully reproduced at high altitude for many generations. Studies have shown that Tibetans have various mechanisms for protection against high-altitude hypoxia, which are probably due, at least in part, to placental adaptation. However, comprehensive in silico analyses of placentas in Tibetans are lacking. We performed a microarray-based comparative transcriptome analysis of 10 Tibetan women from Yushu, Qinghai, CHN (∼3,780 m) and 10 European women living in Leadville, CO, United States (∼3,100 m) for less than three generations. Expression of HIF-1α, STAT3, EGFR, HSP5A, XBP1, and ATF6A mRNA was less in the Tibetan placentas as compared with European placentas. A total of 38 miRNAs were involved in regulating these genes. Differentially expressed genes were enriched for HIF1α signaling pathways, protein processing in the endoplasmic reticulum, PI3K-AKT signaling pathways, and MAPK signaling pathways. Based on the transcriptome profiles, the Tibetan population was distinct from the European population; placental tissues from the Tibetan population are lacking hypoxic responses, and "passivation" occurs in response to hypoxic stress. These results provide insights into the molecular signature of adaptation to high altitudes in these two populations.

MicroRNA-29a inhibits cell proliferation and arrests cell cycle by modulating p16 methylation in cervical cancer.

Cervical cancer is the second most common gynecological malignancy. Accumulating evidence has suggested that microRNAs (miRNAs) are involved in the occurrence and development of cervical cancer. The present study aimed to investigate the function and underlying molecular mechanism of microRNA (miRNA/miR)-29a in cervical cancer. Reverse transcription-quantitative PCR and methylation-specific PCR were used to examine the expression of miR-29a and methylated status of p16 promoter, respectively. Cell Counting Kit-8 analysis and flow cytometry were performed to evaluate cell viability and cycle, respectively. Dual-luciferase reporter assay was performed to verify the interaction between miR-29a and its targets. Western blot analysis was performed to detect the protein levels of DNA methyltransferases (DNMT)3A and DNMT3B. The results demonstrated that miR-29a expression was downregulated in cervical cancer tissues and cells, and negatively correlated with p16 promoter hypermethylation. Furthermore, cell experiments confirmed that miR-29a suppressed cell proliferation and induced cell cycle arrest in HeLa and C-33A cells. Mechanically, miR-29a restored normal methylation pattern of the p16 gene by sponging DNMT3A and DNMT3B. Taken together, the results of the present study demonstrated the epigenetic regulation of tumor suppressor p16 by miR-29a as a unique mechanism, thus providing a rationale for the development of miRNA-based strategies in the treatment of cervical cancer.

Study of the Characterization of Side Population Cells in Endometrial Cancer Cell Lines: Chemoresistance, Progestin Resistance, and Radioresistance.

Introduction: Radiotherapy, combined regimens as platinum-paclitaxel chemotherapy and/or endocrine therapy is an important adjuvant treatment after surgery for endometrial cancer (EC). While, the resistance to them remain unclear. In our study, to separate the characteristics of side population (SP) cells from EC cell lines, study the mechanism of Taxol-resistance, progestin resistance and radioresistanc, and provide the basic for EC. Methods: SP cells from EC cell lines HEC-1A, Ishikawa and RL95-2 were separated by Hoechst 33342 staining and flow cytometry analysis. The expression of breast cancer resistance protein (BCRP) in SP cells and non-SP cells from HEC-1A was examined by immunocytochemistry, and the radiation-resistant and Taxol-resistant characteristics of SP cells and non-SP cells were compared by MTS. Ishikawa, Ishikawa-SP, and Ishikawa-non-SP cells incubated with MPA were selected for cell apoptosis assays by using flow cytometry. The expression of caspase-3 was examined by immunocytochemistry, and autophagy was detected by MDC staining. Results: Small proportions of SP cells, namely, 1.44 ± 0.93%, 2.86 ± 3.09%, and 2.87 ± 1.29%, were detected in HEC-1A, Ishikawa and RL95-2, respectively. There was a stronger clone formation efficiency for the SP cells than for non-SP cells in HEC-1A [(6.02 ± 1.17) vs. (0.53±0.20)%, P = 0.001], and there was a significant difference in the rate of tumourigenicity between the SP cells and non-SP cells in HEC-1A (87.5 vs. 12.5%). There were higher levels of BCRP expression (P = 0.001) and resistance to Taxol and radiation (P < 0.05) in the SP cells than in non-SP cells. After MPA treatment, the apoptosis rates were significantly different among the Ishikawa, Ishikawa-SP and Ishikawa-non-SP groups [(4.64 ± 0.18)%, (4.01 ± 0.43)%, and (9.3 ± 0.67)%; (P = 0.05)], and the expression of Caspase-3 in the Ishikawa group was higher than that in Ishikawa-SP group. The autophagic activity of the Ishikawa-SP cells was the strongest, while the autophagic activity of Ishikawa-non-SP was the weakest. Conclusions: There is a significant enrichment in SP cells among different EC cell lines, and these SP cells be more resistant to Taxol, MPA and radiation therapy. The overexpression of BCRP among SP cells may be the cause of resistance to Taxol, progestin and radiotherapy, which may be related to apoptosis and autophagic activity.

Evaluation of whether serum tumor markers in patients with epithelial ovarian carcinoma change following chemotherapy.

BACKGROUND: Phenotypic and genotypic heterogeneity is a known feature of many cancers. Whether serum tumor marker kinds vary and change following chemotherapy is still unclear. The aim of this study was to investigate whether there is a change in the expression of serum tumor markers following chemotherapy, and the potential clinical significance in patients with epithelial ovarian carcinoma (EOC) or primary serous peritoneal carcinoma (PSPC). METHODS: Samples were collected before surgery, during chemotherapy and during follow-up for enzyme-linked immunosorbent assay (ELISA)-based evaluation of serum CA-125, CA19-9 and CP2 levels in patients with EOC or PSPC who had received primary debulking surgery followed by adjuvant chemotherapy. In total, 72 patients were examined, including 37 patients with recurrent lesions and 35 patients receiving first-line chemotherapy. RESULTS: In 35 de novo patients, 20% (7/35) demonstrated a significant changed serum tumor marker kinds among whom the patients with mucinous carcinoma (57.1%, 4/7) showed resistance to chemotherapy. In the 37 recurrent patients, 51.4% (19/37) had changed serum tumor markers, of whom 57.9% (11/19) presented with serous carcinoma. There was no significant difference in median progression-free survival or overall survival in patients with drug-sensitive or drug-resistant recurrence in patients with changed tumor marker kinds relative to those with unchanged markers. However, for patients with changed serum tumor markers there was a trend towards prolonged survival compared with the unchanged serum tumor marker group. In the 17 patients with secondary recurrence, 37.5% (6/17) had changed tumor marker levels. The ratios of CA-125/CP2 and CA-125/CA19-9 were significantly different after either chemotherapy or recurrence. CONCLUSIONS: Serum tumor marker expression in patients with EOC or PSPC may change after chemotherapy or recurrence, indicating that in addition to the markers that are abnormal before surgery, those markers that are normal should also be monitored during chemotherapy and follow-up.

[Establishment of cisplatin-resistant human endometrial cancer cell line and the study of its resistant mechanisms].

OBJECTIVE: To establish the cisplatin (DDP)-resistant cell line from human endometrial cancer cell line Ishikawa and to investigate its resistant mechanism to DDP. METHODS: A resistant endometrial cancer cell line ISH/DDP was established by gradually increasing dose of cisplatin and high-dose stimulation. The resistant index was estimated by 3-(4,5-dimethylthiazol-zyl)-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. Cell growth curve, doubling time and cell cycle phase distribution were measured; drug-resistant protein of breast cancer resistance protein (BCRP), P-glycoprotein (P-gp) and glutathione-S-transferase-π (GST-π) were examined by immuocytochemistry. Results The DDP-resistant cell line ISH/DDP was established with the resistant index of 3.77. The proliferation of ISH/DDP got slow, doubling time prolonged, which were 40.1 hours, while it was 34.1 hours in Ishikawa (P<0.05); and the cell number of G0/G1 phase [(44.3±5.7)% and (39.0±10.7)%, P>0.05] and G2/M phase [(11.9±0.7)% and (5.7±2.4)%, P<0.05] decreased, while S-phase [(44.2±6.1)% and (55.3±8.4)%, P<0.05] increased compared with parent cells. The comprehensive score of the expression of BCRP in ISH/DDP was 16.3±2.0, while it was 13.4±1.5 in Ishikawa (P<0.05). The score of the expression of P-gp in ISH/DDP and Ishikawa were 15.5±1.2 and 16.1±1.0 (P>0.05), respectively. The score of the expression of GST-π in ISH/DDP and Ishikawa were 15.2±1.9 and 14.9±1.1 (P>0.05). CONCLUSION: ISH/DDP cell line showed a typical resistant phenotype and biological characteristics, which may be accounted for high BCRP expression.

The changes in residual cancer burden after interval debulking surgery are effective in evaluating the response to adjuvant chemotherapy.

OBJECTIVE: To study the clinical significance of the change of residual cancer burden (RCB) of epithelial ovarian carcinoma (EOC) between primary (PDS) and interval debulking surgery (IDS) in order to evaluate the effectiveness of adjuvant chemotherapy. METHODS: Thirty-eight EOC patients with suboptimal PDS with adjuvant chemotherapy were selected for this retrospective study and divided into pathologically negative (group A) and pathologically positive (group B) groups based on the histopathological examination and the change of size of residual disease after IDS. Patients in group B were further divided into groups B1 (partial remission criteria, n = 9), B2 (consistent with stable disease, n = 12) and B3 (consistent with disease progression, n = 4) based on the changes in RCB between PDS and IDS and the guidelines to evaluate the response to treatment in solid tumors (Response Evaluation Criteria in Solid Tumors, RECIST). The responses to chemotherapy evaluated by pathological examination of RCB versus by CA-125, recurrence patterns, and prognoses were analyzed. RESULTS: The clinical benefit rates evaluated by pathological assessment for groups A, B1, B2 and B3 were 100, 100, 100 and 0%, respectively (p < 0.01), whereas the rates were not statistically different when evaluated by CA-125 (100, 100, 91.7 and 100%, respectively; p > 0.05). The median progression-free survival (PFS) for patients in groups A and B was 36 and 6 months, respectively (p < 0.05); the median overall survival (OS) was 93 and 42 months, respectively (p < 0.05). There were no significant differences in median PFS or OS among patients in groups B1, B2 and B3 (PFS: 16, 6 and 1.5 months; OS: 52, 31 and 30.5 months, respectively; all p > 0.05), but there were significant differences in median PFS or OS between B1 and B3. There was no significant difference in recurrence rates between groups A and B (53.8 vs. 72.0%, p > 0.05), but there were significant differences in the rate of drug-resistant recurrence [28.6% (2/7) vs. 72.2% (13/18), p < 0.05] and in median PFS of relapsed patients (19 vs. 4 months, p < 0.05). CONCLUSION: The histopathological assessment of RCB between PDS and IDS may be used to evaluate and predict the response to adjuvant chemotherapy in EOC.