Upregulation of VEGFR1 in a rat model of esophagogastric anastomotic healing.

INTRODUCTION: Anastomotic leakage after gastrointestinal surgery is a significant cause of morbidity and mortality. Esophagogastric and colorectal anastomoses are vulnerable to leakage. Extended knowledge of growth factors and their receptors is needed to understand anatomic healing. METHODS: The expression pattern of vascular growth factor receptor (VEGFR1-3), epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFRα/ß) and keratinocyte growth factor receptor (KGFR) were analyzed by semiquantitative-PCR in the rat intestinal tract and in esophagogastric anastomosis 5d after surgery. RESULTS: VEGFR1, VEGFR2, EGFR, KGFR and PDGFRα expression was observed throughout the intestinal tract including esophagus, stomach, small bowl and colon. VEGFR3 was not found in gastric samples and PDGFRß expression was not detected in the small bowl. Semiquantitative analyses of the VEGFR1, PDGFRα and EGFR expression in esophagogastric anastomotic tissues revealed a 2-fold upregulation of the VEGFR1 in gastric samples, while no change was observed in the esophageal anastomotic side. CONCLUSION: Our results revealed a distinct expression pattern of the investigated growth factor receptors in rat intestinal tract. Showing higher expression levels of growth factor receptors at the gastric anastomotic tissue at the fifth postoperative day suggests a different contribution of the gastric and the esophageal side to the anastomotic healing.

Common variants in the HLA-DQ region confer susceptibility to idiopathic achalasia.

Idiopathic achalasia is characterized by a failure of the lower esophageal sphincter to relax due to a loss of neurons in the myenteric plexus. This ultimately leads to massive dilatation and an irreversibly impaired megaesophagus. We performed a genetic association study in 1,068 achalasia cases and 4,242 controls and fine-mapped a strong MHC association signal by imputing classical HLA haplotypes and amino acid polymorphisms. An eight-residue insertion at position 227-234 in the cytoplasmic tail of HLA-DQß1 (encoded by HLA-DQB1*05:03 and HLA-DQB1*06:01) confers the strongest risk for achalasia (P=1.73×10(-19)). In addition, two amino acid substitutions in the extracellular domain of HLA-DQα1 at position 41 (lysine encoded by HLA-DQA1*01:03; P=5.60×10(-10)) and of HLA-DQß1 at position 45 (glutamic acid encoded by HLA-DQB1*03:01 and HLA-DQB1*03:04; P=1.20×10(-9)) independently confer achalasia risk. Our study implies that immune-mediated processes are involved in the pathophysiology of achalasia.

Murine genetic deficiency of neuronal nitric oxide synthase (nNOS(-/-) ) and interstitial cells of Cajal (W/W(v) ): Implications for achalasia?

BACKGROUND AND AIM: Nitric oxide (NO) is an important inhibitory mediator of esophageal function, and its lack leads to typical features of achalasia. In contrast, the role of intramuscular interstitial cells of Cajal (ICC-IM) and vasoactive intestinal peptide (VIP) in lower esophageal sphincter (LES) function is still controversial. Therefore, we examined the function and morphology of the LES in vivo in NO-deficient (nNOS(-/-) ), ICC-IM-deficient (W/W(v) )-, and wild-type (WT) mice. METHODS: Esophageal manometry was performed with a micro-sized transducer catheter to quantify LES pressure, swallow evoked LES relaxation, and esophageal body motility. The LES morphology was examined by semiquantitative analysis of the immunoreactivity (reduction grade I-IV) of neuronal NOS (nNOS), ICC-IM, and VIP and their correlation with esophageal function. RESULTS: nNOS(-/-) in comparison to WT mice showed a significantly higher LES mean resting pressure with an impaired swallow induced relaxation, whereas W/W(v) mice had a hypotensive LES with decreased relaxation. W/W(v) and nNOS(-/-) mice demonstrated differing degrees of tubular esophageal dysfunction. The reduced immunoreactivity of nNOS correlated with an increased LES pressure and decreased LES relaxation, respectively. Cajal-cell reduction correlated with impaired LES relaxation, whereas VIP reduction revealed no correlation with esophageal function. CONCLUSIONS: The reduction of ICC-IM and nNOS can cause dysfunction of the LES and esophageal peristalsis, whereas VIP reduction seems to have no effect. ICC-IM and nNOS deficiency might be independent relevant causes of esophageal dysfunction similar to that seen in human achalasia.

Minimally invasive surgery for achalasia in patients >40 years: more favorable than anticipated.

PURPOSE: The efficacy of Heller myotomy in patients >40 years-a significant predictor suggesting a favorable response to pneumatic dilation-has been questioned. The aim of our study was to evaluate the results obtained in patients aged <40 and >40 years undergoing minimally invasive surgery (MIS) for achalasia. METHODS: In January 2008, we established the MIS technique for achalasia in our clinic. In the following period from January 2008 to March 2011, 74 patients underwent primary laparoscopic myotomy for achalasia. The procedure was accomplished with an anterior 180° semifundoplication according to Dor in all patients. The Eckardt score and the Gastrointestinal Quality of Life Index (GQLI) served as outcome measures. RESULTS: The median age of patients was 45.5 years (range, 18-85 years) with a median duration of preoperative achalasia symptoms of 57 months (range, 2-468 months). There were no conversions to open surgery and-except for one patient with a sterile pleural effusion-no postoperative complications. At a median follow-up of 12 months, the preoperative Eckardt score of 7.0 (range, 3-12) was found to be significantly decreased to a median of 2 (range, 0-6; P < 0.001). With regard to patients <40 and >40 years, the postoperative Eckardt score obtained in the older patient population was not significantly lower (P = 0.074). There was no statistically significant difference between the two groups with respect to the postoperative GQLI (P = 0.860). Neither gender nor preoperative Botox injection or pneumatic dilation inserted a significant influence on the postoperative clinical outcome (P > 0.05). CONCLUSIONS: Laparoscopic Heller myotomy for achalasia is associated with a high success rate as the primary therapeutic option and after failure of endoscopic therapy. It can be performed safely and with favorable outcomes also in patients >40 years. However, the long-term durability of the procedure remains to be established.

VEGF-D correlates with metastatic disease in gastric cancer patients undergoing surgery.

BACKGROUND: The present study was designed to evaluate the impact of the tyrosine kinase ligands VEGF-A/C/D, PDGF-A/B on tumor dissemination and survival in gastric cancer. This is the first study analyzing all these parameters in a homogeneous patient population undergoing surgery. METHODS: The expression pattern of VEGF-A/C/D and PDGF-A/B was analyzed by reverse transcriptase polymerase chain reaction (RT-PCR) in 69 samples of human gastric adenocarcinoma and correlated with tumor stage and survival. RESULTS: Expression of the ligand VEGF-D significantly correlated with distant metastatic disease (P=0.00001) but not with patient survival. However, VEGF-A inversely correlated with M1 and grading, PDGF-A inversely correlated with pT and pN category. In contrast, VEGF-C and PDGF-B did not have an impact on clinicopathological parameters. CONCLUSIONS: The ligand VEGF-D, rather than the other ligands or tyrosine kinase receptors analyzed, is associated with progressive disease in gastric cancer patients undergoing surgery. The VEGF-D ligand might be a helpful marker indicating disseminated disease, and targeting VEGF-D may be a potential therapeutic strategy, although limitations imposed by the selected sample population have to be considered critically.

Does expression of receptor tyrosine kinases in gastric adenocarcinoma correlate with clinicopathological parameters?

BACKGROUND/AIMS: This study was initiated in order to define the (co-)expression patterns of target receptor tyrosine kinases (RTKs) in human gastric adenocarcinoma and to correlate them with clinicopathological parameters. METHODOLOGY: The (co-)expression pattern of VEGFR1, VEGFR2, VEGFR3, PDGFRalpha, PDGFRbeta and EGFR1 was analyzed in 56 samples of human gastric adenocarcinoma and correlated with staging and survival. RESULTS: VEGFR1, VEGFR2, VEGFR3, PDGFRalpha, PDGFRbeta and EGFR1 were expressed at relevant levels in 79%, 50%, 50%, 63%, 55% and 30%, respectively. VEGFR2, VEGFR3, and PDGFRbeta were significantly co-expressed. Thirty-four percent of gastric adenocarcinoma samples revealed a co-expression of 6 receptors, 27% expressed 5 receptors and only 23% showed expression of 3 receptors or less. Expression of VEGFR1, VEGFR2, VEGFR3, PDGFRalpha, PDGFRbeta and EGFR1 in gastric adenocarcinoma did not significantly correlate with a higher pT-category, the presence of lymph node metastasis (pN+) or overall survival. However, a trend towards a higher pT-category was seen for expression of VEGFR1 without reaching statistical significance. CONCLUSIONS: The data obtained reveal that specific RTKs are significantly co-expressed. However, co-expression of RTKs did not impact on staging or survival. It has to be further analyzed, if the expression of the respective ligands is of higher relevance than the expression of the receptor itself.

Co-expression of receptor tyrosine kinases in esophageal adenocarcinoma and squamous cell cancer.

This study aimed to define the co-expression pattern of target receptor tyrosine kinases (RTKs) in human esophageal adenocarcinoma and squamous cell cancer. The co-expression pattern of vascular endothelial growth factor receptor (VEGFR)1-3, platelet-derived growth factor receptor (PDGFR)alpha/beta and epidermal growth factor receptor 1 (EGFR1) was analyzed by RT-PCR in 50 human esophageal cancers (35 adenocarcinomas and 15 squamous cell cancers). In addition, IHC staining was applied for the confirmation of the expression and analysis of RTK localisation. The adenocarcinoma samples revealed VEGFR1 (97%), VEGFR2 (94%), VEGFR3 (77%), PDGFRalpha (91%), PDGFRbeta (85%) and EGFR1 (97%) expression at different intensities. Ninety-four percent of the esophageal adenocarcinomas expressed at least four out of six RTKs. Similarly, squamous cell cancers revealed VEGFR1 (100%), VEGFR2 (100%), VEGFR3 (53%), PDGFRalpha (100%), PDGFRbeta (87%) and EGFR1 (100%) expression at different intensities. All esophageal squamous cell carcinomas expressed at least four out of six RTKs. While VEGFR1-3 and PDGFRalpha and EGFR1 was expressed by tumor cells, PDGFRbeta was restricted to stromal cells, which also depicted a PDGFRalpha expression. Our results revealed a high rate of RTK co-expression in esophageal adenocarcinoma and squamous cell cancer and may encourage application of multi-target RTK inhibitors within a multimodal concept as a promising novel approach for innovative treatment strategies.

PDGFRalpha/beta expression correlates with the metastatic behavior of human colorectal cancer: a possible rationale for a molecular targeting strategy.

As new multi-target tyrosine kinase inhibitors are emerging in the therapy of various malignancies, our aim was to define the co-expression pattern of receptor-tyrosine-kinase platelet-derived growth factor receptors alpha and beta (PDGFRalpha/beta) in human colorectal cancer. The co-expression pattern of PDGFRalpha/beta was analyzed by RT-PCR in 99 histologically confirmed human colorectal carcinomas and five colorectal cancer cell lines. In addition, immunohistochemical (IHC) staining was applied for confirmation of expression and analysis of receptor tyrosine kinase (RTK) localisation. The colorectal cancer cell lines that were analysed revealed varying expression intensities of PDGFRalpha and PDGFRbeta. The majority of human colorectal cancer specimens revealed a PDGFRalpha (83%) or PDGFRbeta (60%) expression. While PDGFRalpha showed a predominantly cytoplasmic staining in tumor cells as well as in stromal pericytes, PDGFRbeta was restricted to stromal pericytes only. Furthermore, PDGFRalpha expression significantly correlated with lymph node metastasis (P=0.0082) and advanced UICC stages III/IV (P=0.018) in older patients (P=0.043). PDGFRbeta expression only revealed a trend towards lymphatic dissemination (P=0.099). Co-expression of PDGFRalpha/beta occurred in 57% of the colorectal cancer samples, whereas another 29% of the samples depicted mono-expression of PDGFRalpha or PDGFRbeta. Notably, PDGFRalpha/beta expression significantly correlated with lymphatic metastasis (P=0.007) and advanced UICC stages III/IV (P=0.017) in older patients (P=0.03). In summary, our results revealed that PDGFRalpha/beta expression significantly correlates with lymphatic dissemination and therefore encourages application of PDGFRalpha/beta RTK-inhibitors within a combination therapy.

Coexpression of receptor-tyrosine-kinases in gastric adenocarcinoma--a rationale for a molecular targeting strategy?

AIM: To define the (co-)expression pattern of target receptor-tyrosine-kinases (RTK) in human gastric adenocarcinoma. METHODS: The (co-)expression pattern of VEGFR1-3, PDGFR alpha/beta and EGFR1 was analyzed by RT-PCR in 51 human gastric adenocarcinomas. In addition, IHC staining was applied for confirmation of expression and analysis of RTK localisation. RESULTS: The majority of samples revealed a VEGFR1 (98%), VEGFR2 (80%), VEGFR3 (67%), PDGFR alpha (82%) and PDGFR beta (82%) expression, whereas only 62% exhibited an EGFR1 expression. 78% of cancers expressed at least four out of six RTKs. While VEGFR1-3 and PDGFR alpha revealed a predominantly cytoplasmatic staining in tumor cells, accompanied by an additional nuclear staining for VEGFR3, EGFR1 was almost exclusively detected on the membrane of tumor cells. PDGFR beta was restricted to stromal pericytes, which also depicted a PDGFR alpha expression. CONCLUSION: Our results reveal a high rate of receptor-tyrosine-kinases coexpression in gastric adenocarcinoma and might therefore encourage an application of multiple-target RTK-inhibitors within a combination therapy.

Expression of chemokine receptor CXCR4 in esophageal squamous cell and adenocarcinoma.

BACKGROUND: Prognosis of esophageal cancer is poor despite curative surgery. The chemokine receptor CXCR4 has been proposed to distinctly contribute to tumor growth, dissemination and local immune escape in a limited number of malignancies. The aim of our study was to evaluate the role of CXCR4 in tumor spread of esophageal cancer with a differentiated view of the two predominant histologic types--squamous cell and adenocarcinoma. METHODS: Esophageal cancer tissue samples were obtained from 102 consecutive patients undergoing esophageal resection for cancer with curative intent. The LSAB+ System was used to detect the protein CXCR4. Tumor samples were classified into two groups based on the homogeneous staining intensity. A cut-off between CXCR4w (= weak expression) and CXCR4s (= strong expression) was set at 1.5 (grouped 0-1.5 versus 2.0-3). Long-term survival rates were calculated using life tables and the Kaplan-Meier method. Using the Cox's proportional hazards analysis, a model of survival prediction was established. RESULTS: The overall expression rate for CXCR4 in esophageal squamous cell carcinoma was 94.1%. Subdividing these samples, CXCR4w was found in 54.9% and CXCR4s in 45.1%. In adenocarcinoma, an overall expression rate of 89.1% was detected with a weak intensitiy in 71.7% compared to strong staining in 29.3% (p = 0.066 squamous cell versus adenocarcinoma). The Cox's proportional hazards analysis identified the pM-category with a hazard ratio (HR) of 1.860 (95% CI: 1.014-3.414) (p = 0.045), the histologic tumor type (HR: 0.334; 95% CI: 0.180-0.618) (p = 0.0001) and the operative approach (transthoracic > transhiatal esophageal resection) (HR: 0.546; 95% CI: 0.324-0.920) (p = 0.023) as independent factors with a possible influence on the long-term prognosis in patients with esophageal carcinoma, whereas CXCR4 expression was statistically not significant (>0.05). CONCLUSION: Expression of the chemokine receptor CXCR4 in esophageal cancer is of major relevance in both histologic entities--squamous cell and adenocarcinoma. Though with lack of statistical significance, strong CXCR4 expression revealed a poorer long-term prognosis following curative esophagectomy in both histologic subtypes. Thus, the exact biological functions of CXCR4 in terms of tumor dissemination of esophageal cancer is yet undetermined. Inhibition of esophageal cancer progression by CXCR4 antagonists might be a promising therapeutic option in the future.

Sex steroid metabolism in human peripheral blood mononuclear cells changes with aging.

CONTEXT: Dehydroepiandrosterone (DHEA) mainly exerts indirect action via downstream conversion toward sex steroids within peripheral target cells including immune cells. In vitro DHEA has been shown to enhance IL-2 release from T lymphocytes, whereas it inhibits IL-6 secretion. Conversely, aging is associated with a decline in both DHEA and IL-2, whereas IL-6 increases. OBJECTIVE: The objective of the study was to investigate age-related differences in expression and functional activity of steroidogenic enzymes involved in downstream conversion of DHEA in peripheral blood mononuclear cells (PBMCs). DESIGN: This study was cross-sectional. PARTICIPANTS/SETTING: Healthy young men (n = 8; age range, 23-29 yr) and healthy middle-aged men (n = 8; age range, 52-66 yr) were studied in an academic setting. MEASURES: mRNA expression of steroidogenic enzymes in PBMCs was measured by qualitative and quantitative RT-PCR analysis and enzyme activity assays after incubation of PBMCs with radiolabeled DHEA, 4-androstene-3,17-dione (androstenedione), and testosterone. RESULTS: RT-PCR analysis showed expression of all enzymes required for DHEA conversion toward active androgens and to the immune-stimulatory metabolite androstenediol. Steroid conversion patterns indicated a particularly increased activity of 17beta-hydroxysteroid dehydrogenase type 5 (17beta-HSD5) in the older men, demonstrated by significantly higher conversion rates of DHEA to androstenediol and of androstenedione to testosterone (all P < 0.05). By contrast, conversion of DHEA to androstenedione via 3beta-HSD occurred at a similar rate. Quantitative RT-PCR analysis revealed increased expression of 17beta-HSD 5 mRNA in PBMCs from the older men. CONCLUSIONS: Our results provide evidence for significant changes in sex steroid metabolism by human PBMCs with aging, which may represent an endocrine link to immune senescence.