Optimized flow cytometric detection of transient receptor potential vanilloid-1 (TRPV1) in human hematological malignancies.

The ectopic overexpression of transient receptor potential vanilloid-1 (TRPV1) has been detected in numerous solid cancers, including breast, prostate, pancreatic, and tongue epithelium cancer. However, the expression of TRPV1 in hematological malignancies remains unknown. Here we show through in silico analysis that elevated TRPV1 mRNA expression occurs in a range of hematological malignancies and presents an optimized flow cytometry method to rapidly assess TRPV1 protein expression for both cell lines and primary patient samples. Three anti-TRPV1 antibodies were evaluated for intracellular TRPV1 detection using flow cytometry resulting in an optimized protocol for the evaluation of TRPV1 in hematological malignant cell lines and patients' peripheral blood mononuclear cells (PBMC). Overexpression of TRPV1 was observed in THP-1 (acute monocytic leukemia) and U266B1 (multiple myeloma, MM), but not U937 (histiocytic lymphoma) compared to healthy PBMC. TRPV1 was also detected in all 49 patients including B-cell non-Hodgkin's lymphoma (B-NHL), MM, and others and 20 healthy controls. TRPV1 expression was increased in 8% of patients (MM = 2, B-NHL = 2). In conclusion, we provide an optimized flow cytometry method for routine expression analysis of clinical samples and show that TRPV1 is increased in a subset of patients with hematological malignancies.

New therapeutic targets for the prevention of infectious acute exacerbations of COPD: role of epithelial adhesion molecules and inflammatory pathways.

Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major contributor, chronic obstructive pulmonary disease (COPD) accounting for approximately 3 million deaths annually. Frequent acute exacerbations (AEs) of COPD (AECOPD) drive clinical and functional decline in COPD and are associated with accelerated loss of lung function, increased mortality, decreased health-related quality of life and significant economic costs. Infections with a small subgroup of pathogens precipitate the majority of AEs and consequently constitute a significant comorbidity in COPD. However, current pharmacological interventions are ineffective in preventing infectious exacerbations and their treatment is compromised by the rapid development of antibiotic resistance. Thus, alternative preventative therapies need to be considered. Pathogen adherence to the pulmonary epithelium through host receptors is the prerequisite step for invasion and subsequent infection of surrounding structures. Thus, disruption of bacterial-host cell interactions with receptor antagonists or modulation of the ensuing inflammatory profile present attractive avenues for therapeutic development. This review explores key mediators of pathogen-host interactions that may offer new therapeutic targets with the potential to prevent viral/bacterial-mediated AECOPD. There are several conceptual and methodological hurdles hampering the development of new therapies that require further research and resolution.

TRPV1 mediates capsaicin-stimulated metabolic activity but not cell death or inhibition of interleukin-1ß release in human THP-1 monocytes.

Human monocytes and dendritic cells express transient receptor potential vanilloid 1 (TRPV1) which may play a role in mediating the inflammatory, immune and cancer surveillance responses of these cells. The aim of the present study was to investigate TRPV1 expression and function in THP-1 monocytic cells. RT-PCR and Western blot were used to detect TRPV1. The metabolic activity and viability of THP-1 cells following exposure to vanilloids was assessed using resorufin production from rezazurin. Cytokine release was measured using ELISA. TRPV1 was expressed in cultured THP-1 monocytic cells and naïve monocytes. Lower concentrations (<250 µM) of capsaicin, but not other putative TRPV1 agonists, were shown to stimulate cell metabolic activity, whereas at concentrations >250 µM, all agonists decreased metabolic activity. Capsaicin-stimulated THP-1 metabolic activity was blocked by the TRPV1 antagonist, 5-iodo-resiniferatoxin (5'-IRTX), whereas the decline in resorufin production by THP-1 cells at higher capsaicin concentrations (due to cell death), was not affected by 5'-IRTX. Finally, capsaicin (≤125 µM) significantly increased lipopolysaccharide-stimulated IL-6 and TNF-α release from THP-1 cells, whereas phytohaemagglutinin-stimulated IL-1ß, TNF-α, MCP-1 and IL-6 release were concentration-dependently inhibited by capsaicin. Modulation of IL-1ß release was not TRPV1 mediated. Overall, these results show that functional TRPV1 channels are present in naïve monocytes and THP-1 cells, and when activated, increase cell metabolic activity. In addition, capsaicin modifies cytokine release from THP-1 cells and induces cell death, most likely by a mechanism that is independent of TRPV1 activation.

Cell Stress Signaling Cascades Regulating Cell Fate.

Initiating anti-apoptotic signaling or triggering cell death depends to a great extent on the nature or source of cellular stress and cell type. Interplay between each stress response eventually determines the fate of stressed cell. Numerous factors induce cell death by a number of pathways including apoptosis, autophagy and necrosis. Not surprisingly, some of the pathways are interrelated to each other through a mediator that could articulate the entire mechanism. The present review attempts to consolidate all the pathways included in intrinsic cellular stress such as oxidative stress and autophagy, endoplasmic reticular stress (ERS) and mitophagy and apoptosis as fate in cell stress. These stress responses are a hallmark of numerous diseases including neurodegenerative diseases, diabetes and cancer. Understanding the cross-talk between different intrinsic cell stress responses will help to develop new therapeutic targets and hence lead to the development of new therapeutics.

TRPV1 Channels in Immune Cells and Hematological Malignancies.

Transient receptor potential vanilloid-1 (TRPV1) is a member of the TRP family of channels that are responsible for nociceptive, thermal, and mechanical sensations. Originally associated exclusively with sensory neurons, TRPV1 is now known to be present in almost all organs, including cells of the immune system, where TRPV1 has been shown to play a pivotal role in inflammation and immunity. Monocytes, macrophages, and dendritic cells express TRPV1, with both mouse and human studies suggesting that TRPV1 activation protects against endotoxin-induced inflammation. In contrast, TRPV1 (and other TRP channels) appears to be required for T-cell receptor activation by mitogens. Additionally, studies in cell lines derived from hematological and other malignancies suggest altered expression/function of TRPV1 might serve as a target for novel cytotoxic therapies.

Capsaicin-Induced Death of Human Haematological Malignant Cell Lines Is Independent of TRPV1 Activation.

The effect of the plant-derived vanilloid, capsaicin (CAP), on the metabolic activity of THP-1, U266B1 and U937 hematological malignancy cells was determined. CAP reduced metabolic activity in a concentration-dependent manner in the three cell lines. A biphasic effect was observed on THP-1 cells (EC50: IC50 (95% CI) 32.9 (19.9-54.3)/219 (144-246) µmol/l). U266B1 cells were more resistant to CAP than THP-1 and U937. Metabolic activity was significantly inhibited by CAP in U937 compared to U266B1 cells (IC50: 197 versus 431 µmol/l, respectively, p < 0.008). Transient receptor potential vanilloid-1 (TRPV1) and CB1 antagonists (SB452533 and AM251, respectively) suppressed the CAP-induced increase in THP-1 cell metabolic activity (p < 0.001). AM251 and SB452533 appeared to act as partial agonists and displayed a synergistic effect with CAP in U937 cells. CAP inhibits the metabolic activity of malignant hematological cells through non-TRPV1-dependent mechanisms.

Effects of atorvastatin on oxidative stress in chronic kidney disease.

AIM: Statins have pleiotropic effects that include attenuation of oxidative stress that may be relevant for chronic kidney disease (CKD) patients. We investigated the effect of long-term atorvastatin therapy on oxidative stress biomarkers in CKD patients. METHODS: This was a pre-specified secondary analysis of data from a randomized, double-blind, placebo-controlled trial (Lipid lowering and Onset of Renal Disease, LORD) in CKD patients. Participants received 10 mg/day atorvastatin (n = 47) or placebo (n = 39) for 3 years. Plasma measures (total F2-isoprostanes, malondialdehyde. protein carbonyls, uric acid, glutathione peroxidase (GPx) activity and total antioxidant capacity (TAC) ) were performed at baseline and at 3 years. Age and sex matched participants (n = 34) with normal kidney function were controls. RESULTS: CKD patients had significantly (P < 0.05) increased F2-isoprostanes and uric acid and decreased GPx activity compared with controls. When comparing the treatment (atorvastatin (A) vs placebo (P) ) change from baseline to 3 years, there were no significant differences (P > 0.05) in the group difference of the change values: (mean (95% CI), F2-isoprostanes = 5.3 (-29.2 to 39.8) pg/mL, protein carbonyls = 0.03 (-0.13 to 0.19) nmol/mg, GPx activity = -0.10 (-4.73 to 4.52) (U/L), uric acid = 8.8 (-33.9 to 51.6) µmol/L or TAC = -0.03 (-0.10 to 0.04) mmol/L. A significant difference (P = 0.04) in the change in malondialdehyde between groups, 1.52(0.09 to 2.96) µmol/L, was due to a large decrease in the placebo group. CONCLUSION: CKD patients had elevated oxidative stress that was not attenuated by atorvastatin 10 mg/day for 3 years.

Vanilloid-like agents inhibit aggregation of human platelets.

INTRODUCTION: Plant-derived and endogenous vanilloid-like agents exert their effects on cells through transient receptor potential vanilloid-1 (TRPV1). Little is known about the effects of these agents on platelet aggregation. We investigated the effect of various vanilloid-like agents on in-vitro platelet aggregation and tested whether this action is mediated through TRPV1. Understanding the mechanism of action of these compounds in platelets is important in that these compounds may be developed as novel anti-platelet agents. MATERIALS AND METHODS: The effects of plant-derived (capsaicin; dihydrocapsaicin, DHC) and endogenous vanilloid-like agents (N-oleoyldopamine, OLDA; N-arachidonoyl-dopamine, NADA) on platelet aggregation were investigated using ADP (5, 10µM), collagen (4, 8µg/mL) and arachidonic acid (AA, 300, 400µg/mL) as agonists. The direct effects of these agents on platelet viability were also determined using an LDH release assay. RESULTS: Capsaicin, OLDA and NADA inhibited ADP-induced platelet aggregation in a concentration-dependent manner. OLDA and NADA, but not capsaicin and DHC, inhibited collagen-induced aggregation, whereas AA-induced aggregation was inhibited by capsaicin, DHC and NADA, but not OLDA. Inhibition of aggregation was not due to direct toxicity of these agents towards platelets. The TRPV1 antagonist, SB-452533, did not affect inhibition of ADP-induced platelet aggregation by capsaicin and OLDA. CONCLUSIONS: These results demonstrate that the endovanilloids, OLDA and NADA, and plant-derived vanilloid, capsaicin, inhibit ADP-induced platelet aggregation. Collagen-induced aggregation was inhibited only by endovanilloids, whereas AA-induced aggregation was inhibited by capsaicin, DHC and NADA. This inhibition was not due to direct toxic effects of these agents, nor was inhibition of ADP-induced aggregation TRPV1 mediated.

The impact of pre-intervention rate of kidney function change on the assessment of CKD progression.

BACKGROUND: Without a run-in phase, chronic kidney disease (CKD) patients enrolled in clinical trials may not be identified as having progressive disease. The aim of this analysis was to quantify the effects of a run-in phase on kidney function outcome in CKD patients enrolled in the Lipid Lowering and Onset of Renal Disease (LORD) trial. METHODS: The LORD trial assessed the effects of atorvastatin on the rate of change in the estimated glomerular filtration rate (eGFR) and included patients with serum creatinine 120 µmol/l. In this post hoc analysis, we assessed eGFR change during the 12-month period prior to enrolment, the 3-month run-in phase and the first 12-month period of the trial. Eighty of the original 132 patients (where retrospective data were available) were included. The rate of eGFR change during each period was compared. RESULTS: Overall kidney function decreased during the 12 months prior to enrolment by (mean, SD) 0.39 ± 0.98 ml/min/1.73 m(2)/month, improved during the 3-month run-in phase by 0.48 ± 2.90 ml/min/1.73 m(2)/month and decreased during the first 12 months of the trial by 0.15 ± 0.57 ml/min/1.73 m(2)/month. However, only 39 % of patients had declining eGFR during the 12 months prior, 19 % in the 3-month run-in and 42 % during the first 12-month study phase. CONCLUSION: Most patients (>60 %) entering this clinical trial had stable or improving kidney function. Enrolment was associated with further improved kidney function, which may have been due to 'regression to the mean' or to the Hawthorne effect. Investigators should include a run-in period to establish the presence of eGFR decline to use as an inclusion criterion in clinical trials assessing this measure of CKD progression.

Hypolipidaemic effect of crude extract from Carpobrotus rossii (pigface) in healthy rats.

Carpobrotus rossii (CR) was used by the Aboriginal population and early European settlers both as a food and therapeutic agent. Based on the presence of flavonoids in CR and results from our previous in vitro investigations, this study aimed to determine whether consumption of CR crude leaf extract: (a) affected lipoprotein profile, resting glucose, systolic blood pressure and vascular function, and (b) produced toxic effects (haematological measures, organ weight) in healthy rats. Male Hooded-Wistar rats (~230 g) were supplemented for 4 weeks with CR extract in their drinking water (35 mg/kg body weight daily). CR extract produced a significant decrease (18%, p=0.033) in atherogenic lipoproteins (but not high density lipoprotein). CR supplemented animals showed no signs of haematological toxicity and body and organ weight, daily fluid and food consumption and in vitro vascular responsiveness were similar for both groups. CR also increased (40%, p=0.049) the renal concentration of 3-hydroxy-3-methylglutaric acid (HMG), consistent with HMG-containing CR flavonoids being bioavailable, and therefore possessing the potential to interfere with cholesterol synthesis pathways. CR extract appears to be safe to ingest and may reduce cardiovascular risk.

Effects of atorvastatin on biomarkers of inflammation in chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is associated with inflammation. The effects of atorvastatin on biomarkers of inflammation were assessed in CKD patients in the LORD trial. METHODS: 117 patients with serum creatinine >120 µmol/L were randomized to receive atorvastatin 10 mg/day (56) or placebo (61) and followed for a mean of 2.5 years. 33 individuals with normal kidney function were controls. Outcomes included comparison of changes in pentraxin-3 (PTX3), TNF-α, CRP, IL-6, IL-8, and IL-10 between atorvastatin and placebo-treated patients. RESULTS: At baseline, compared with controls, CKD patients had increased PTX3 (mean, 1.08 vs. 0.58 ng/mL; p < 0.001), CRP (4.9 vs. 1.5 mg/L; p < 0.001), IL-8 (6.00 vs. 4.58 pg/mL; p = 0.001), IL-10 (59.0 vs. 17.6 pg/mL; p = 0.007), and TNF-α (18.0 vs. 5.6 ng/mL; p < 0.001). In patients with raised baseline plasma IL-6/8/10 and/or PTX3 the eGFR decline during the trial was significantly less in those treated with atorvastatin compared to placebo (mean change, -3.36; vs. + 1.25 mL/min/1.73 m2/year; difference, 4.61 95% CI 0.98 - 8.25; p = 0.002), whilst those without raised inflammatory biomarkers showed no difference. Placebo treated patients with raised TNF-α levels had no eGFR decline (p > 0.90), whereas in atorvastatin-treated patients eGFR declined (p = 0.05). CONCLUSIONS: CKD patients with inflammation treated with atorvastatin had significantly less eGFR decline. Larger studies using statin therapy, specifically enrolling CKD patients with inflammation, may be worthwhile exploring.

Tachykinin (NK1, NK2 and NK3) receptor, transient receptor potential vanilloid 1 (TRPV1) and early transcription factor, cFOS, mRNA expression in rat tissues following systemic capsaicin treatment.

Capsaicin, the pungent component of chilli pepper, stimulates TRPV1-expressing cells which are followed by desensitisation to subsequent exposure to capsaicin and other TRPV1 activators. At high systemic doses (>125 mg/kg), capsaicin produces long-term changes in both tachykinin receptor and TRPV1 expression and function in rats. However, whether desensitising (low) doses of capsaicin (~50 mg/kg) affect tachykinin receptor and TRPV1 gene expression in the short term has yet to be investigated. The aim of the present study was to compare tachykinin receptor (NK1, NK2 and NK3) and TRPV1 mRNA expression 24h after administration of capsaicin (50 mg/kgs.c.). Tachykinin receptor and TRPV1 mRNA were detected in all tissues studied with expression levels differing by up to 2500-fold between tissues. The highest expression of TRPV1 and NK1 mRNA was observed in the salivary gland, whereas NK2 mRNA expression was highest in the urinary bladder and NK3 mRNA expression in the frontal cortex. In the cervical spinal cord of rats treated with capsaicin, NK1 and NK3 mRNA expression were reduced by 56% and 80%, respectively (P<0.05), whereas NK2 and TRPV1 mRNA expression were increased 2.2- and 1.4-fold, respectively (P<0.05). NK1 and NK2 mRNA expression were decreased (P<0.05) in the urinary bladder and gastric fundus, respectively, following capsaicin treatment. There was a marked 100-fold increase in cFOS mRNA expression and 100-fold decrease in NK2 mRNA expression in the whole blood of capsaicin-treated rats. In conclusion, these studies show that tachykinin receptor and TRPV1 mRNA expression undergo significant changes within 24h of systemic low-dose capsaicin administration.

Relationship between antioxidant enzyme genotype and activity and kidney function: a case-control study.

BACKGROUND: Oxidative stress is associated with the progression of chronic kidney disease (CKD). Links between antioxidant enzyme SNPs such as superoxide dismutase (SOD) Ala16Val, glutathione peroxidase (GPx) Pro197Leu and catalase C- 262T and CKD have not been investigated. This study compared antioxidant genotypes and activities of CKD patients with population controls, and determined their relationship to kidney function. METHODS: CKD patients (n = 230) and controls (n = 224) were screened for the GPx, SOD and catalase SNPs. Plasma and red blood cell (RBC) GPx, RBC SOD and RBC catalase activities, and estimated glomerular filtration rate (eGFR) were measured. RESULTS: Significantly more CKD patients (n = 5) had the GPx Leu/Leu genotype compared to controls (n = 0), and had lower eGFR (p = 0.054). CKD patients had significantly lower plasma GPx and RBC catalase activities compared to controls, whereas RBC GPx and RBC SOD activities were significantly higher in CKD patients (p < 0.001). CONCLUSIONS: CKD is associated with reduced plasma GPx and catalase activities and enhanced RBC GPx and SOD activities. Although, genotype frequencies were similar for both groups, lower eGFR was associated with the GPx Leu/ Leu genotype.

Relationships between single nucleotide polymorphisms of antioxidant enzymes and disease.

The presence and progression of numerous diseases have been linked to deficiencies in antioxidant systems. The relationships between single nucleotide polymorphisms (SNPs) arising from specific antioxidant enzymes and diseases associated with elevated oxidative stress have been studied with the rationale that they may be useful in screening for diseases. The purpose of this narrative review is to analyse evidence from these studies. The antioxidant enzyme SNPs selected for analysis are based on those most frequently investigated in relation to diseases in humans: superoxide dismutase (SOD2) Ala16Val (80 studies), glutathione peroxidise (GPx1) Pro197Leu (24 studies) and catalase C-262T (22 studies). Although the majority of evidence supports associations between the SOD2 Ala16Val SNP and diseases such as breast, prostate and lung cancers, diabetes and cardiovascular disease, the presence of the SOD2 Ala16Val SNP confers only a small, clinically insignificant reduction (if any) in the risk of these diseases. Other diseases such as bladder cancer, liver disease, nervous system pathologies and asthma have not been consistently related to this SOD SNP genotype. The GPx1 Pro197Leu and catalase C-262T SNP genotypes have been associated with breast cancer, but only in a small number of studies. Thus, currently available evidence suggests antioxidant enzyme SNP genotypes are not useful for screening for diseases in humans.

Effects of atorvastatin on NGAL and cystatin C in chronic kidney disease: a post hoc analysis of the LORD trial.

BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C are biomarkers of kidney injury and function, respectively. This study assessed whether plasma NGAL and/or serum cystatin C predicted baseline estimated glomerular filtration rate (eGFR) and urinary protein excretion, rate of change of eGFR and urinary protein excretion and whether atorvastatin influenced changes in these biomarkers in patients with chronic kidney disease (CKD). METHODS: This is a post hoc analysis of the Lipid Lowering and Onset of Renal Disease trial, a randomized double-blind, placebo-controlled trial where 88 patients with Stages 2-4 CKD received atorvastatin 10 mg/day (48) or placebo (40). Stored blood samples were analysed for NGAL and cystatin C at baseline and a mean of 1.5 and 2.9 years later. Serum creatinine and Modification of Diet in Renal Disease (MDRD) eGFR were obtained three monthly. RESULTS: There were negative associations between NGAL and cystatin C and eGFR (P = 0.025 and P < 0.001, respectively) at all time points. There were no associations between baseline NGAL and cystatin C and rate of change of eGFR (P = 0.44 and P = 0.49, respectively). Baseline NGAL but not cystatin C (P = 0.043 and P = 0.35, respectively) predicted rate of change of urinary protein excretion. In atorvastatin-treated patients, NGAL decreased (mean, -7.4 ng/mL/year; SD 128.4), whereas it increased in the placebo group [mean, 4.6 ng/mL/year; SD 56.6), the difference being statistically significant (P = 0.049). CONCLUSIONS: NGAL is a biomarker of existing CKD but did not predict CKD progression. Atorvastatin reduced plasma NGAL but the significance and mechanisms require further investigation. Atorvastatin had no significant effect on cystatin C.

Vascular function and mortality in haemodialysis patients: a pilot study.

BACKGROUND: Haemodialysis patients often have impaired vascular function that can contribute to mortality. Endothelial-dependent and -independent vascular function can be assessed using the brachial artery reactivity (BAR) technique that measures flow-mediated dilatation (FMD) and the response to glyceryl trinitrate (GTN), respectively. AIMS: The aim of this pilot study was to determine whether BAR measurements in haemodialysis patients were associated with mortality. METHODS: Brachial artery responses to FMD and administration of GTN were assessed in consecutive haemodialysis patients. Patients were then followed up to 18 months after BAR measurements. RESULTS: Seventeen patients were included in the study. After 18 months of follow-up, patients were divided into two groups: survived (n=12) and deceased (n=5). Patients who survived had a significantly greater median percentage vasodilatation to GTN than those who died (19.1% vs 8.8%; P=0.04); and a significantly greater median area under the diameter change-time curve (318 vs 146 mm/s; P=0.03). However, there were no significant differences between survivors and deceased in median percentage vasodilation to FMD (6.0% vs 4.3%; P=0.21), time to peak dilation (45 vs 40s; P=0.66) or area under the diameter change-time curve (35.5 vs 20 mm/s; P=0.29). CONCLUSION: In this pilot study in a small group of haemodialysis patients, endothelial-independent vasodilatory response to GTN was associated with mortality and was of better prognostic value than the endothelial-dependent response to FMD. This finding needs to be investigated in a larger cohort.

Hematologic, plasma biochemical, and other indicators of the health of Tasmanian platypuses (Ornithorhynchus anatinus): predictors of mucormycosis.

The fungal disease mucormycosis has affected Tasmanian platypuses for nearly three decades. We investigated the influences of mucormycosis on the hematologic, plasma biochemical, and other indicators of health in free-living platypuses across 18 Tasmanian river catchments. Live trapping enabled sampling of 161 (apparently) healthy and six ulcerated, mucormycosis-affected platypuses in 75 rivers and streams between January 2008 and June 2009. There were no obvious differences in any hematologic or biochemical measures between healthy and mucormycosis-affected platypuses. However, multivariate analysis revealed that ulceration was associated with living at higher altitudes, low tail fat content (high tail fat index), and low trypanosome load. There was evidence of overall lymphocytosis and monocytosis in animals from areas currently affected by mucormycosis, which suggests that some level of immune response to the introduced fungus is now widespread in disease-affected catchments. Animals from currently, historically, and possibly disease-affected catchments had lower neutrophil counts, mean cell volumes, plasma alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase levels, and higher plasma gamma-glutamyl transpeptidase and platelet counts compared to animals from catchments with no evidence of infection. Reference intervals were generated for all hematologic and biochemical measurements. Since this is the most comprehensive, systematic, and large-scale assessment of the health of the Tasmanian platypus to date, these references intervals should act as the standard against which future studies of platypuses in Tasmania should be compared.

Effects of systemic capsaicin treatment on TRPV1 and Tachykinin NK(1) receptor distribution and function in the nucleus of the solitary tract of the adult rat.

Vanilloids including capsaicin and resiniferatoxin (RTX) have been identified as potential novel anti-inflammatory and analgesic compounds. We have previously shown that systemic capsaicin administration to neonatal rats evokes profound long-term alterations in transient receptor potential vanilloid 1 (TRPV1)- and neurokinin 1 (NK(1)) receptor-mediated respiratory responses in the commissural nucleus of the solitary tract (cNTS). Whether this effect of capsaicin is unique to developmentally immature animals is unknown. Therefore, in the present study, we investigated the effects of systemic capsaicin administration to adult rats on NK(1) receptor binding sites, TRPV1 and NK(1) immunoreactivity and function in the cNTS. Microinjection of capsaicin (1 nmol) or RTX (75 pmol) into the cNTS of vehicle-pretreated rats produced a profound bradypnoea (maximum change: -45 breaths·min(-1)) and a small increase in tidal volume (VT). Similarly, microinjection of the selective NK(1) receptor agonists [Sar(9), Met(O(2))(11)]substance P (SP; 66 pmol) and septide (20 pmol) decreased respiratory frequency and increased VT. Thirteen to 18 days after systemic administration of capsaicin (125 mg·kg(-1) s.c.), the bradypnoeic responses to both capsaicin and RTX were absent (p < 0.05), indicative of sensory neuron ablation/desensitisation. Systemic capsaicin pretreatment significantly (p < 0.05) reduced the density of both [(125)I]Bolton-Hunter SP binding sites (NK(1) receptors) and NK(1) receptor immunoreactivity in the cNTS, but did not alter the respiratory responses evoked by microinjection of [Sar(9), Met(O(2))(11)]SP and septide into this region. These studies show that systemic capsaicin administration reduces NK(1) receptor density in the cNTS without adversely affecting NK(1) receptor function at this site. We speculate that adult rats may be more resistant than neonatal rats to the neuroplastic effects of systemic capsaicin administration.

Glutathione peroxidase, superoxide dismutase and catalase genotypes and activities and the progression of chronic kidney disease.

BACKGROUND: Oxidative stress has been linked to the progression of disease, including chronic kidney disease (CKD). The aim of the present study was to determine the association between single-nucleotide polymorphisms (SNPs) of the antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase and their activities and the progression of CKD. METHODS: This is a prospective cohort study of 185 CKD patients (Stages 2-4), followed for up to 12 months. All patients were genotyped for SNPs of SOD (SOD Ala16Val), GPx (GPx Pro197Leu) and catalase (C-262T). The rate of change over the study period of estimated glomerular filtration rate (eGFR), plasma and red blood cell (RBC) GPx, RBC SOD and RBC catalase activities were determined. RESULTS: CKD patients with the SOD Ala/Val and Val/Val genotypes had a significantly greater eGFR decline compared to those with the Ala/Ala genotype (Ala/Val compared with Ala/Ala odds ratio (OR) 0.35, 95% CI 0.19 to 0.64, P = 0.001; Val/Val compared with Ala/Ala OR 0.25, 95% CI 0.10 to 0.65, P = 0.005). The progression of CKD was not associated with SNPs of the GPx or catalase genes studied but there was a direct relationship between the rate of change of plasma GPx activity and the rate of change of eGFR over 12 months (P = 0.025). CONCLUSION: CKD patients with the SOD Ala/Val and Val/Val genotypes have a greater decline in kidney function than those with the Ala/Ala genotype.