Excessive leukotriene B4 in nucleus tractus solitarii is prohypertensive in spontaneously hypertensive rats

Inflammation within the brainstem microvasculature has been associated with chronic cardiovascular diseases. We found that the expression of several enzymes involved in arachidonic acid (AA) - leukotriene B4 (LTB4) production was altered in NTS of SHR. LTB4 produced from AA by 5-lipoxygenase (5LOX) is a potent chemoattractant of leukocytes. Leukotriene B4-12-hydroxydehydrogenase (LTB4-12-HD), which degrades leukotriene B4 (LTB4), was down-regulated compared to Wistar-Kyoto rats (WKY). Quantitative RT-PCR revealed that LTB4-12-HD was reduced by 63 and 58% in the NTS of adult SHR and pre-hypertensive (PH) SHR respectively, compared to age-matched WKY rats (n=6). 5LOX gene expression was up-regulated in the NTS of SHR (~50%; n=6). LTB4 levels were increased in the NTS of the SHR (17%; n=10, p<0.05). LTB4 receptors BLT1 (but not BLT2), were expressed on astroglia in the NTS but not neurons or vessels. Microinjection of LTB4 into the NTS of WKY rats increased both leukocyte adherence and arterial pressure for over 4 days (peak: +15 mmHg; P<0.01). In contrast, blockade of NTS BLT1 receptors lowered blood pressure in the SHR (peak: -13 mmHg; P<0.05) but not WKY rats. Thus, excessive amounts of LTB4 in NTS of SHR possibly as a result of up-regulation of 5LOX and down regulation of LTB412-HD, can induce inflammation. Since blockade of NTS BLT1 receptors lowered arterial pressure in the SHR their endogenous activity may contribute to the hypertensive state of this rodent model. Thus, inflammatory reactions in the brainstem are causally associated with neurogenic hypertension

Immune Dysregulation and Tumor-Associated Gene Changes in Recurrent Respiratory Papillomatosis: A Paired Microarray Analysis

Recurrent respiratory papillomas (RRP) are benign airway tumors, caused primarily by human papillomaviruses (HPV) types 6 and 11. The disease is characterized by multiple recurrences after surgical removal, with limited effective therapy. To identify novel targets for future therapy, we established transcriptional profiles for actively growing papillomas compared with autologous, clinically normal, laryngeal epithelia (adjacent tissue). Total ribonucleic acid (RNA) from 12 papillomas and 12 adjacent tissues were analyzed by microarray, and the matched sets of tissues compared by paired t test, to identify differentially expressed genes in papilloma tissues while minimizing variations intrinsic to individual patients. Quantitative polymerase chain reaction (PCR) was used to confirm the relative expression levels for a subset of genes. Within the 109 differentially expressed transcripts whose expression varied at least three-fold were two large groups of genes with related functions. The first group consisted of 18 genes related to host defense, including both innate and adaptive immunity. The second group contained 37 genes that likely contribute to growth of papillomas as benign tumors, since the altered pattern of expression also had been reported previously in many cancers. Our results support our previous studies that document a systemic TH2-like adaptive immune response in RRP, and suggest that there is a role for altered innate immunity in RRP as well. We propose that HPV 6 and 11 infection establishes a tumorigenic microenvironment characterized by alteration of both innate inflammatory signals and adaptive immune responses that prevent effective TH1-like response, in conjunction with altered expression of numerous genes that regulate cellular growth and differentiation