Comparative transcriptomic analysis reveals the molecular changes of acute pancreatitis in experimental models

BACKGROUND

Acute pancreatitis (AP) encompasses a spectrum of pancreatic inflammatory conditions, ranging from mild inflammation to severe pancreatic necrosis and multisystem organ failure. Given the challenges associated with obtaining human pancreatic samples, research on AP predominantly relies on animal models. In this study, we aimed to elucidate the fundamental molecular mechanisms underlying AP using various AP models.

AIM

To investigate the shared molecular changes underlying the development of AP across varying severity levels.

METHODS

AP was induced in animal models through treatment with caerulein alone or in combination with lipopolysaccharide (LPS). Additionally, using Ptf1α to drive the specific expression of the hM3 promoter in pancreatic acinar cells transgenic C57BL/6J- hM3/Ptf1α^(cre) mice were administered Clozapine N-oxide to induce AP. Subsequently, we conducted RNA sequencing of pancreatic tissues and validated the expression of significantly different genes using the Gene Expression Omnibus (GEO) database.

RESULTS

Caerulein-induced AP showed severe inflammation and edema, which were exacerbated when combined with LPS and accompanied by partial pancreatic tissue necrosis. Compared with the control group, RNA sequencing analysis revealed 880 significantly differentially expressed genes in the caerulein model and 885 in the caerulein combined with the LPS model. Kyoto Encyclopedia of Genes and Genomes enrichment analysis and Gene Set Enrichment Analysis indicated substantial enrichment of the TLR and NOD-like receptor signaling pathway, TLR signaling pathway, and NF-κB signaling pathway, alongside elevated levels of apoptosis-related pathways, such as apoptosis, P53 pathway, and phagosome pathway. The significantly elevated genes in the TLR and NOD-like receptor signaling pathways, as well as in the apoptosis pathway, were validated through quantitative real-time PCR experiments in animal models. Validation from the GEO database revealed that only MYD88 concurred in both mouse pancreatic tissue and human AP peripheral blood, while TLR1, TLR7, RIPK3, and OAS2 genes exhibited marked elevation in human AP. The genes TUBA1A and GADD45A played significant roles in apoptosis within human AP. The transgenic mouse model hM3/Ptf1α^(cre) successfully validated significant differential genes in the TLR and NOD-like receptor signaling pathways as well as the apoptosis pathway, indicating that these pathways represent shared pathological processes in AP across different models.

CONCLUSION

The TLR and NOD receptor signaling pathways play crucial roles in the inflammatory progression of AP, notably the MYD88 gene. Apoptosis holds a central position in the necrotic processes of AP, with TUBA1A and GADD45A genes exhibiting prominence in human AP.

[The association between baseline TPOAb and/or TgAb positivity and thyroid immune-related adverse events in patients with malignancies following treatment with immune checkpoint inhibitors]

Objective: To investigate the association between positive anti-thyroid peroxidase antibody (TPOAb) and/or anti-thyroglobulin antibody (TgAb) and the occurrence of thyroid immune-related adverse events (irAEs) in patients with malignant tumors who treated with immune checkpoint inhibitors (ICIs). Methods: A case-control study. A total of 116 patients with malignant tumor who received ICIs treatment and underwent thyroid function evaluation at Peking Union Medical College Hospital from January 2017 to April 2023 were enrolled retrospectively, including 77 males and 39 females, with a median age of (M(Q1, Q3)) 63.0 (55.0, 70.0) years. The patients were divided into the euthyroid group (n=58) and the thyroid irAEs group (n=58) according to whether thyroid irAEs occurred after ICIs treatment. The clinical characteristics and baseline anti-thyroid antibodies associated with the occurrence of thyroid irAEs after ICIs treatment in patients with malignant tumors were evaluated. Variables with statistical significance in univariate analysis were included in multivariate logistic regression model to analyze the risk factors for thyroid irAEs in patients with malignant tumors who received ICIs treatment. Results: In irAEs group, therewore 4 (3.4%) cases of clinical thyrotoxicosis, 23(19.8%) cases of subclinical thyrotoxicosis, 23 (19.8%) cases of clinical hypothyroidism, and 8(6.9%) cases of subclinical hypothyroidism. The positive rate of anti-thyroid antibodies at baseline in the thyrioid irAEs group was higher than that in the euthyroid group［16/58（27.6%）vs 3/58（5.2%），P=0.001］. After at least one course of ICIs treatment, the incidence of thyroid irAEs in patients with positive anti-thyroid antibodies at baseline was 84.2% (16/19), whereas it was 43.3% (42/97) in patients with negative anti-thyroid antibodies(P=0.001). Univariate logistic regression analysis showed that gender (OR=2.812, 95%CI:1.257-6.293), baseline thyroid autoantibodies were positive (OR=6.984, 95%CI: 1.909-25.547), baseline TgAb positivity (OR=8.909, 95%CI: 1.923-41.280), and baseline TPOAb positivity (OR=7.304, 95%CI: 1.555-34.308) were associated with thyroid irAEs (all P<0.05). Multivariate logistic regression analysis indicated that baseline TgAb positivity (OR=7.637, 95%CI: 1.617-36.072) was a risk factor for thyroid irAEs (P=0.01). Conclusions: The incidence of thyroid irAEs is higher in patients who are positive for baseline TPOAb and/or TgAb compared to those who are negative for TPOAb and TgAb. Patients with positive TgAb at baseline are at high risk of developing thyroid irAEs.

Fourteen-day vonoprazan and low- or high-dose amoxicillin dual therapy for eradicating Helicobacter pylori infection: A prospective, open-labeled, randomized non-inferiority clinical study

Background and aim

We previously reported that vonoprazan-amoxicillin (VA) dual therapy for 7 or 10 days is not satisfactorily efficacious for Helicobacter pylori (H. pylori) eradication. We aimed to explore the efficacy of VA dual therapy for 14 days as a first-line treatment for H. pylori infection.

Methods

This was a single center, prospective, open-labeled, randomized non-inferiority clinical study conducted in China. Treatment naïve H. pylori infected patients were randomized into two groups: 20 mg vonoprazan (VPZ) b.i.d. in combination with low-dose (1000 mg b.i.d.) or high-dose (1000 mg t.i.d) amoxicillin for 14 days. ¹³C-urea breath tests were used to access the cure rate at least 4 weeks after treatment.

Results

A total of 154 patients were assessed and 110 subjects were randomized. The eradication rate of VPZ with b.i.d. amoxicillin or t.i.d. amoxicillin for 14 days was 89.1% and 87.3% by intention-to-treat analysis, respectively, and 94.1% and 95.9% by per-protocol analysis, respectively. The eradication rate and incidence of adverse events were not different between the two groups.

Conclusion

VPZ with b.i.d. or t.i.d. amoxicillin for 14 days provides satisfactory efficacy as a first-line treatment for H. pylori infection in China.

Analysis of oral microbiota alterations induced by Helicobacter pylori infection and vonoprazan-amoxicillin dual therapy for Helicobacter pylori eradication

BACKGROUND

The oral cavity is considered a potential reservoir of Helicobacter pylori (H. pylori), and the imbalance of oral microbiota directly reflects the health of the host. We aimed to explore the relationship among oral microbiota, H. pylori infection, and vonoprazan-amoxicillin (VA) dual therapy for H. pylori eradication.

METHODS

Helicobacter pylori-positive patients were randomized into low- or high-dose VA dual therapy (i.e., amoxicillin 1 g b.i.d. or t.i.d. and vonoprazan 20 mg b.i.d) for 7 or 10 days. H. pylori-negative patients served as normal controls. Saliva samples were collected from 41 H. pylori-positive patients and 13 H. pylori-negative patients. The oral microbiota was analyzed by 16S rRNA gene sequencing, followed by bioinformatics analysis.

RESULTS

Helicobacter pylori-positive patients had higher richness and diversity and better evenness of oral microbiota than normal controls. Beta diversity analysis estimated by Bray-Curtis or weighted UniFrac showed distinct clustering between H. pylori-positive patients and normal controls. The number of bacterial interactions was reduced in H. pylori-positive patients compared with that in negative patients. Forty-one patients evaluated before and after successful H. pylori eradication were divided into low (L-VA) and high dose (H-VA) amoxicillin dose groups. The alpha and beta diversity of the oral microbiota between L-VA and H-VA patients exhibited no differences at the three time points (before eradication, after eradication, and at confirmation of H. pylori infection cure).

CONCLUSION

Helicobacter pylori infection could alter the diversity, composition, and bacterial interactions of the oral microbiota. Both L-VA and H-VA dual therapy showed minimal influence on the oral microbiota.

Optimization of vonoprazan-amoxicillin dual therapy for eradicating Helicobacter pyloriinfection in China: A prospective, randomized clinical pilot study

BACKGROUND

Vonoprazan-amoxicillin (VA) dual therapy has been shown to achieve acceptable cure rates for treatment of Helicobacter pylori(H. pylori) in Japan. Its effectiveness in other regions is unknown. We aimed to explore the efficacy of VA dual therapy as first-line treatment for H. pyloriinfection in China.

METHODS

This was a single center, prospective, randomized clinical pilot study conducted in China. Treatment naive H. pyloriinfected patients were randomized to receive either low- or high-dose amoxicillin-vonoprazan consisting of amoxicillin 1 g either b.i.d. or t.i.d plus VPZ 20 mg b.i.d for 7 or 10 days. ¹³ C-urea breath tests were used to access the cure rate at least 4 weeks after treatment.

RESULTS

Three hundred and twenty-three patients were assessed, and 119 subjects were randomized. The eradication rates of b.i.d. amoxicillin for 7 and 10 days, t.i.d. amoxicillin for 7 and 10 days were 66.7% (16/24), 89.2% (33/37), 81.0% (17/21), and 81.1% (30/37) (p = .191) by intention-to-treat analysis, respectively, and 72.7% (16/22), 89.2% (33/37), 81.0% (17/21), and 81.1% (30/37) (p = .454) by per-protocol analysis, respectively.

CONCLUSION

Neither 7- or 10-day VA dual therapy with b.i.d. or t.i.d. amoxicillin provides satisfied efficacy as the first-line treatment for H. pyloriinfection in China. Further optimization is needed.

[Advances in clinical prediction scores for prognosis of coronavirus disease-2019]

Coronavirus Disease-2019 (COVID-19) has been a major public health issue all over the world, placing a significant burden on available healthcare resources. The most common types of COVID-19 are the mild and common forms. Although the proportion of the severe-critical types is smaller, the rate of death is significantly higher and the medical resources required tend to be greater. Thus, a variety of scores based on other disease and COVID-19 were used to assess the risk of poor prognosis on the COVID-19, including the common scores for community-acquired pneumonia, sepsis and viral pneumonia. Unfortunately, the above scores often lacked an adequate description of the applicable population or were at high risk of bias with unknown applicability. Therefore, the article summarized the existing scores, aiming to provide a reference for clinical prognostic risk assessment.

Altered Gut Microbiota and Short-Chain Fatty Acids After Vonoprazan-Amoxicillin Dual Therapy for Helicobacter pylori Eradication

The combination of vonoprazan (VPZ) and amoxicillin (VA therapy) has been shown to achieve acceptable eradication rates for Helicobacter pylori (H. pylori). Herein, our aim was to explore the short-term effect of VA therapy on the gut microbiota and short-chain fatty acids (SCFAs) using human fecal samples. A total of 119 H. pylori-positive patients were randomized into low- or high-dose VA therapy (i.e., amoxicillin 1 g b.i.d. or t.i.d. and VPZ 20 mg b.i.d.) for 7 or 10 days. Thirteen H. pylori-negative patients served as controls. Fecal samples were collected from H. pylori-positive and H. pylori-negative patients. The gut microbiota and SCFAs were analyzed using 16S rRNA gene sequencing and gas chromatography–mass spectrometry, respectively. The gut microbiota in H. pylori-positive patients exhibited increased richness, diversity, and better evenness than matched patients. Fifty-three patients studied before and after H. pylori eradication were divided into low (L-VA) and high (H-VA) amoxicillin dose groups. The diversity and composition of the gut microbiota among L-VA patients exhibited no differences at the three time points. However, among H-VA patients, diversity was decreased, and the microbial composition was altered immediately after H-VA eradication but was restored by the confirmation time point. The decreased abundance of Anaerostipes, Dialister, and Lachnospira induced by H-VA was associated with altered SCFA levels. VA dual therapy for H. pylori eradication has minimal negative effects on gut microbiota and SCFAs.

Upregulation of oncogene Activin A receptor type I by Helicobacter pylori infection promotes gastric intestinal metaplasia via regulating CDX2

BACKGROUND

Activin A receptor type I (ACVR1) is involved in tumorigenesis. However, the underlying molecular mechanisms of ACVR1 in gastric cancer (GC) and its association with Helicobacter pylori remained unclear.

MATERIALS AND METHODS

The Cancer Genome Atlas (TCGA) and Gene Expression Profiling Interactive Analysis (GEPIA) database were utilized to explore the ACVR1 expression in GC and normal control and its association with survival. The ACVR1 was knocked out using CRISPR/Cas-9; RNA sequencing analysis was performed in AGS cells with ACVR1 knockout and normal control. Functional experiments (CCK-8, colony-forming, and transwell assays) were conducted to demonstrate the role of ACVR1 in cell proliferation, invasion, and metastasis. H. pylori-infected C57/BL6 models were established. ACVR1, p-Smad1/5, and CDX2 were detected in AGS cells cocultured with H. pylori strains. The CDX2 and key elements of BMP signaling pathway were detected in AGS cells with ACVR1 knockout and normal control. In addition, Immunohistochemistry was performed to detect the ACVR1 and CDX2 expression in gastric samples.

RESULTS

ACVR1 expression was higher in GC than normal control from TCGA, GEPIA, and samples collected from our hospital (p < 0.05). ACVR1 promoted cell proliferation, migration, and invasion in vitro. Both cagA⁺ and cagA^- H. pylori could upregulate the expression ACVR1 (p < 0.05). Downregulation of ACVR1 inhibited the H. pylori-induced cell proliferation, migration, and invasion (p < 0.05). H. pylori increased the expression of p-Smad 1/5 and CDX2. The CDX2 and key elements of BMP signaling pathway were downregulated in AGS cells with ACVR1 knockout. ACVR1 and CDX2 were upregulated in the stage of intestinal metaplasia (IM). Moreover, ACVR1 and CDX2 expressions were higher in H. pylori-positive group than H. pylori-negative group (p < 0.05).

CONCLUSION

Our data indicate that H. pylori infection increases ACVR1 expression, promoting gastric IM via regulating CDX2, which is an essential step in H. pylori carcinogenesis.

Expression and prognostic significance of the DNA damage response pathway and autophagy markers in gastric cancer

Gastric cancer (GC) is a leading cause of mortality and morbidity worldwide. We assessed the expression patterns of DNA damage response (DDR)-related markers, including ATM, CHK2, p-p53 (S15), Rad51, and BRCA2 and autophagy-related proteins including p62 and Beclin-1 in 153 GC specimens using immunohistochemistry staining. GC tissues showed lower levels of ATM, CHK2, p-p53, BRCA2, and higher levels of Rad51 compared to adjacent normal tissues. The autophagy-related protein p62 was upregulated, whereas Beclin-1 was downregulated in human GC groups. Additionally, different statuses of DDR pathways and autophagy characterized by protein expression were associated with overall survival. Our results indicated that the impairment of DNA damage and autophagy may be implicated in gastric cancer progression and its clinical prognosis.

Pancreatic necrosis and severity are independent risk factors for pancreatic endocrine insufficiency after acute pancreatitis: A long-term follow-up study

BACKGROUND

Pancreatic endocrine insufficiency after acute pancreatitis (AP) has drawn increasing attention in recent years.

AIM

To assess the impact of risk factors on the development of pancreatic endocrine insufficiency after AP.

METHODS

This retrospective observational long-term follow-up study was conducted in a tertiary hospital. Endocrine function was evaluated by the oral glucose tolerance test. The data, including age, sex, body mass index, APACHE II score, history of smoking and drinking, organ failure, pancreatic necrosis, debridement of necrosis (minimally invasive and/or open surgery), and time interval, were collected from the record database.

RESULTS

A total of 361 patients were included in the study from January 1, 2012 to December 30, 2018. A total of 150 (41.6%) patients were diagnosed with dysglycemia (including diabetes mellitus and impaired glucose tolerance), while 211 (58.4%) patients had normal endocrine function. The time intervals (mo) of the above two groups were 18.73 ± 19.10 mo and 31.53 ± 27.27 mo, respectively (P = 0.001). The morbidity rates of pancreatic endocrine insufficiency were 46.7%, 28.0%, and 25.3%, respectively, in the groups with different follow-up times. The risk factors for pancreatic endocrine insufficiency after AP were severity (odds ratio [OR] = 3.489; 95% confidence interval [CI]: 1.501-8.111; P = 0.004) and pancreatic necrosis (OR = 4.152; 95%CI: 2.580-6.684; P = 0.001).

CONCLUSION

Pancreatic necrosis and severity are independent risk factors for pancreatic endocrine insufficiency after AP. The area of pancreatic necrosis can affect pancreatic endocrine function.

LncRNA SNHG7 is an Oncogenic Biomarker Interacting with MicroRNA-193b in Colon Carcinogenesis

BACKGROUND

The expression and significance of small nucleolar RNA host gene 7 (SNHG7) in early-stage colon carcinogenesis remains unclear.

METHODS

The level of SNHG7 and microRNA-193b (miR-193b) was detected by qRT-PCR in colon tumor tissues and cells. The interaction of SNHG7 and miR-193b and the influence of SNHG7 silencing on colon tumor cells was evaluated.

RESULTS

Stepwise upregulated SNHG7 in colon advanced adenomas and early-stage cancer negatively correlates with miR-193b level, the direct interaction was confirmed in vitro. SNHG7 silencing in HT29 cells decreased proliferation and promoted apoptosis by inhibiting K-ras/ERK/cyclinD1.

CONCLUSIONS

SNHG7 is an oncogenic biomarker in colon carcinogenesis. The effect may be mediated by interaction with miR-193b.

[Etiology and clinical features of primary adrenal insufficiency]

Objective: To summarize the etiology of primary adrenal insufficiency (PAI) and analyze its clinical features. Methods: A retrospective analysis was performed in the Department of Endocrinology, Peking Union Medical College Hospital from October 1981 to June 2019. Patients with PAI as the first symptom were enrolled. The etiology of PAI was analyzed and the clinical characteristics was also summarized. Results: A total of 131 patients with PAI were enrolled, including 87 males and 44 females (57 adolescents, and 74 adults). The age ranged from 0 to 73 years. The primary cause of PAI in adolescents was genetic defects (52.6%, 30/57), in which congenital adrenal dysplasia caused by DAX1 gene deficiency accounted for 50.0% (15/30), followed by autoimmunity (22.8%, 13/57). The primary cause of adult PAI was infection (58.1%, 43/74), of which tuberculosis accounted for the majority (93.0%, 40/43), and autoimmune adrenalitis accounted for 19.0% (14/74). Compared with the tuberculosis group, female patients were more common, and the onset age was younger, the plasma cortisol, serum sodium, fasting blood glucose, creatinine and aldosterone were lower (all P<0.05), and serum potassium and renin levels were higher in the autoimmune adrenalitis group (both P<0.05). Conclusions: In the current study, the proportion of PAI caused by infection in the adult group was higher than that in the adolescent group. The most common cause of adult PAI was tuberculosis infection. The most common cause of childhood PAI was genetic defects. Autoimmune damage to the adrenal glands may be more severe than tuberculosis infection.

Impact factors that modulate gastric cancer risk in Helicobacter pylori-infected rodent models

Gastric cancer causes a large social and economic burden to humans. Helicobacter pylori (H pylori) infection is a major risk factor for distal gastric cancer. Detailed elucidation of H pylori pathogenesis is significant for the prevention and treatment of gastric cancer. Animal models of H pylori-induced gastric cancer have provided an invaluable resource to help elucidate the mechanisms of H pylori-induced carcinogenesis as well as the interaction between host and the bacterium. Rodent models are commonly used to study H pylori infection because H pylori-induced pathological processes in the stomachs of rodents are similar to those in the stomachs of humans. The risk of gastric cancer in H pylori-infected animal models is greatly dependent on host factors, bacterial determinants, environmental factors, and microbiota. However, the related mechanisms and the effects of the interactions among these impact factors on gastric carcinogenesis remain unclear. In this review, we summarize the impact factors mediating gastric cancer risk when establishing H pylori-infected animal models. Clarifying these factors and their potential interactions will provide insights to construct animal models of gastric cancer and investigate the in-depth mechanisms of H pylori pathogenesis, which might contribute to the management of H pylori-associated gastric diseases.

Downregulation of tumor suppressor RACK1 by Helicobacter pylori infection promotes gastric carcinogenesis through the integrin β-1/NF-κB signaling pathway

Receptor of activated protein kinase C 1 (RACK1) is downregulated in gastric cancer and is involved in modulating NF-κB signaling pathway activity. However, the underlying molecular mechanisms regulating RACK1 expression are unclear. In this study, we demonstrated that downregulated expression of RACK1 was observed in gastric cancer tissue compared to adjacent normal tissue and was correlated with poor prognosis in patients. Helicobacter pylori (H. pylori) infection downregulated RACK1 expression in concert with canonical NF-κB signaling pathway activation in vivo and in vitro. RACK1 overexpression suppressed NF-κB signaling pathway activation as well as the release of downstream proinflammatory cytokines. In addition, RACK1 downregulation increased integrin β-1 expression, while integrin β-1 silencing decreased NF-κB signaling activation. Moreover, H. pylori infection downregulated RACK1 but upregulated integrin β-1 expression at the precancerous lesion stages in human subjects. Our data indicate that H. pylori infection promotes the upregulation of integrin β-1 expression via downregulation of RACK1 expression, which subsequently leads to the elevated activation of the NF-κB signaling pathway, an essential step in H. pylori-induced carcinogenesis.

Analysis of key genes and signaling pathways involved in Helicobacter pylori-associated gastric cancer based on The Cancer Genome Atlas database and RNA sequencing data

BACKGROUND

Helicobacter pylori (H. pylori) infection is associated with the development of gastric cancer, although the mechanism is unclear. Herein, this study aimed to clarify the key genes and signaling pathways involved in H. pylori pathogenesis based on The Cancer Genome Atlas (TCGA) database and RNA sequencing analysis.

MATERIALS AND METHODS

Forty-nine gastric cancer samples (16 with H. pylori and 33 without H. pylori) and 35 cancer-adjacent normal samples from TCGA database were analyzed by bioinformatics. The differentially expressed genes between H. pylori-positive and H. pylori-negative patients were verified in 18 gastric cancer (GC) samples (9 with H. pylori and 9 without H. pylori), which were analyzed using RNA sequencing. Survival analysis was carried out to explore associations between the differentially expressed genes and prognosis. Bioinformatics analysis was performed to determine the signaling pathways associated with H. pylori.

RESULTS

The baseline level of clinical features from TCGA database and RNA sequencing showed no differences between the H. pylori-positive and H. pylori-negative GC groups (P > 0.05). TP53 was shown to be upregulated in the H. pylori-positive group in both TCGA database and RNA sequencing data, which also showed higher expression in the GC tissues than in adjacent normal tissues (P < 0.05). CCDC151, CHRNB2, GMPR2, HDGFRP2, and VSTM2L were shown to be downregulated in the H. pylori-positive group by both TCGA database and RNA sequencing, which also showed lower expression in the GC tissues than in adjacent normal tissues (P < 0.05). GC patients with low expression levels of HDGFRP2 had a poor prognosis (P < 0.05). Thirty-three signaling pathways and 10 biological processes were found to be positively associated with H. pylori infection (P < 0.05, FDR < 0.05).

CONCLUSIONS

These results indicate that some genes (TP53, CCDC151, CHRNB2, GMPR2, HDGFRP2, VSTM2L) and previously unidentified signaling pathways (eg, the Hippo signaling pathway) might play an important role in H. pylori-associated GC.

LKB1/AMPK inhibits TGF-β1 production and the TGF-β signaling pathway in breast cancer cells

Adenosine monophosphate-activated protein kinase (AMPK) acts as a fuel gauge that maintains energy homeostasis in both normal and cancerous cells, and has emerged as a tumor suppressor. The present study aims to delineate the functional relationship between AMPK and transforming growth factor beta (TGF-β). Our results showed that expression of liver kinase B1 (LKB1), an upstream kinase of AMPK, impeded TGF-β-induced Smad phosphorylation and their transcriptional activity in breast cancer cells, whereas knockdown of LKB1 or AMPKα1 subunit by short hairpin RNA (shRNA) enhanced the effect of TGF-β. Furthermore, AMPK activation reduced the promoter activity of TGF-β1. In accordance, type 2 diabetic patients taking metformin displayed a trend of reduction of serum TGF-β1, as compared with those without metformin. A significant reduction of serum TGF-β1 was found in mice after treatment with metformin. These results suggest that AMPK inhibits the transcription of TGF-β1, leading to reduction of its concentration in serum. Finally, metformin suppressed epithelial-to-mesenchymal transition of mammary epithelial cells. Taken together, our study demonstrates that AMPK exerts multiple actions on TGF-β signaling and supports that AMPK can serve as a therapeutic drug target for breast cancer.

2'-C-branched ribonucleosides. 2. Synthesis of 2'-C-beta-trifluoromethyl pyrimidine ribonucleosides

[structure: see text]. The first synthesis of 2'-C-beta-trifluoromethyl pyrimidine ribonucleosides is described. 1,2,3,5-Tetra-O-benzoyl-2-C-beta-trifluoromethyl-alpha-D-ribofuranose (3) is prepared from 1,3,5-tri-O-benzoyl-alpha-D-ribofuranose (1) in three steps and converted to 3,5-di-O-benzoyl-2-C-beta-trifluoromethyl-alpha-D-1-ribofuranosyl bromide (5). The 1-bromo derivative (5) is found to be a powerful reaction intermediate for the synthesis of ribonucleosides. The reaction of silylated pyrimidines with (5) in the presence of HgO/HgBr2 affords exclusively the beta-anomers (6-8). Deprotection of (6-8) with ammonia in methanol yields the 2'-C-beta-trifluoromethyl nucleosides (9-11).

Antithrombotic effects of low-molecular-weight heparin calcium (LMWH-Ca) in experimental models

The antithrombotic activity of low-molecular-weight heparin calcium (LMWH-Ca) was studied in venous and arterial thrombosis models, arterial thrombosis model in rats, arterio-venous shunt model and venous thrombosis model in rabbits. The data showed that LMWH-Ca reduced thrombus formation in a dose-dependent manner. It suggests that LMWH-Ca is a potent antithrombotic agent for venous thrombosis, and also may be a beneficial therapeutic agent in arterial thrombosis.

Endogenous inhibitors of nitric oxide synthesis and lipid peroxidation in hyperlipidemic rabbits

AIM

To examine whether the elevation of endogenous NG, NG-dimethylarginine (DMA) content is related to lipid peroxidation in the high lipid-fed rabbit.

METHODS

In high lipid diet-fed rabbits, concentrations of serum cholesterol, triglyceride, malondialdehyde (MDA), and DMA were measured, and endothelium-dependent relaxation to acetylcholine (ACh) was tested.

RESULTS

After 6-wk on a high lipid-diet, the levels of serum total cholesterol, triglyceride, MDA, and DMA were increased vs those in control group (MDA was 2.88 +/- s 0.20 vs 1.54 +/- 0.13 nmol.L-1, P < 0.01 and DMA was 1.51 +/- 0.07 vs 0.75 +/- 0.13 mumol.L-1, P < 0.01), while the endothelium-dependent vasodilation in the isolated thoracic aorta was impaired (the maximal response to ACh was 45.59 +/- 3.10 vs 76.93 +/- 5.68%). Supplementation with vitamin E decreased MDA and DMA content and improved the endothelium-dependent vasodilation.

CONCLUSIONS

An increase in serum concentration of DMA may be secondary to the elevation of lipid peroxides in the hyperlipidemic rabbit.