Cyclooxygenase metabolites mediate glomerular monocyte chemoattractant protein-1 formation and monocyte recruitment in experimental glomerulonephritis

Celecoxib alleviates pathological cardiac hypertrophy and fibrosis via M1-like macrophage infiltration in neonatal mice

Cardiac hypertrophy is an adaptive response to all forms of heart disease, including hypertension, myocardial infarction, and cardiomyopathy. Cyclooxygenase-2 (COX-2) overexpression results in inflammatory response, cardiac cell apoptosis, and hypertrophy in adult heart after injury. However, immune response-mediated cardiac hypertrophy and fibrosis have not been well documented in injured neonatal heart. This study showed that cardiac hypertrophy and fibrosis are significantly attenuated in celecoxib (a selective COX-2 inhibitor)-treated P8 ICR mice after cryoinjury. Molecular and cellular profiling of immune response shows that celecoxib inhibits the production of cytokines and the expression of adhesion molecular genes, increases the recruitment of M1-like macrophage at wound site, and alleviates cardiac hypertrophy and fibrosis. Furthermore, celecoxib administration improves cardiac function at 4 weeks after injury. These results demonstrate that COX-2 inhibition promotes the recruitment of M1-like macrophages during early wound healing, which may contribute to the suppression of cardiac hypertrophy and fibrosis after injury.

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Cryoinjury successfully induces cardiac hypertrophy and fibrosis in P8 ICR mice

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COX-2 inhibition alleviates cardiac hypertrophy and fibrosis after cryoinjury

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MCP-1 significantly increases in COX-2 inhibition

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COX-2 inhibition improves cardiac repair in P8 ICR mice by recruiting M1-like macrophages

Plasma MCP-1 levels in bipolar depression during cyclooxygenase-2 inhibitor combination treatment

BACKGROUND

Neuroinflammation plays a role in the pathophysiology of Bipolar Disorder Depression (BDD) and altered levels of inflammatory mediators, such as monocyte chemoattractant protein-1 (MCP-1, aka CCL2) have been reported. This study reports specifically on MCP-1 levels, as a potential marker of BDD and/or treatment response in patients receiving combination treatment with the cyclooxygenase-2 inhibitor, celecoxib (CBX).

METHODS

In this randomized, 10-week, double-blind, two-arm, placebo-controlled study, 47 patients with treatment resistant BDD received either escitalopram (ESC) + CBX, or ESC + placebo (PBO). Plasma MCP-1 levels were measured at 3 time points in the BDD subjects, and in a healthy control (HC) group. Depression severity was quantified using the Hamilton Depression Scale (HAMD-17).

RESULTS

The CBX group had significantly lower HAMD-17 scores vs. PBO at week 4 (P = 0.026) and week 8 (P = 0.002). MCP-1 levels were not significantly different in BDD vs. HC subjects at baseline (P = 0.588), nor in CBX vs. PBO groups at week 8 (P = 0.929). Week 8 HAMD-17 scores and MCP-1 levels were significantly negatively correlated in treatment non-responders to CBX or PBO (P = 0.050). Non-responders had significantly lower MCP-1 levels vs. responders at weeks 4 (P = 0.049) and 8 (P = 0.014). MCP-1 was positively correlated with pro-inflammatory analytes in the PBO group and with anti-inflammatory analytes in the CBX group.

CONCLUSIONS

Combination treatment reduced treatment resistance and augmented antidepressant response. Baseline plasma MCP-1 levels were not altered in BDD patients. Since non-responders had lower levels of MCP-1, elevated MCP-1 may indicate a better response to CBX + SSRI treatment.

Cardio-renal safety of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used therapeutic class in clinical medicine. These are sub-divided based on their selectivity for inhibition of cyclooxygenase (COX) isoforms (COX-1 and COX-2) into: (1) non-selective (ns-NSAIDs), and (2) selective NSAIDs (s-NSAIDs) with preferential inhibition of COX-2 isozyme. The safety and pathophysiology of NSAIDs on the renal and cardiovascular systems have continued to evolve over the years following short- and long-term treatment in both preclinical models and humans. This review summarizes major learnings on cardiac and renal complications associated with pharmaceutical inhibition of COX-1 and COX-2 with focus on preclinical to clinical translatability of cardio-renal data.

Quantification of Meloxicam in Human Plasma Using Ionic Liquid-Based Ultrasound-Assisted In Situ Solvent Formation Microextraction Followed by High-Performance Liquid Chromatography

A robust extraction method against the variations of sample ionic strength viz. ionic liquid-based ultrasound-assisted in situ solvent formation microextraction (IL-UA-ISFME) was coupled for the first time with high-performance liquid chromatography-ultraviolet detection (HPLC-UV), and successfully used as a more sustainable approach for the determination of meloxicam (MEL) in human plasma. Herein, a hydrophobic IL (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by adding a hydrophilic IL (1-butyl-3-methylimidazolium tetrafluoroborate) to aqueous sample solution containing an ion-exchange reagent (sodium hexafluorophosphate). The target analyte was transferred into the IL medium while the extraction solvent was completely dispersed into the sample using ultrasonic irradiation and then, the settled enriched phase was injected to HPLC. Firstly, main factors affecting the microextraction performance were evaluated and optimized. The linearity was in the range of 5-1,500 ng mL-1 with regression coefficient corresponding to 0.997. Limits of detection (LOD; signal-to-noise ratio (S/N) = 3) and quantification (LOQ, S/N = 10) were 1 and 5 ng mL-1, respectively. An acceptable recovery range of 82.1-93.6% and satisfactory intra-assay (3.6-4.8%, n = 6) and inter-assay (3.3-5.1%, n = 9) precision as well as remarkable sample clean up exhibited good efficiency of the method. The freeze-thaw stability study was performed for samples and standard solutions. To study the applicability of the proposed method, it was employed for the determination of MEL in human plasma after oral administration of the drug and some pharmacokinetic data were achieved. The technique proved to be accurate and reliable for the screening intentions.

Meloxicam fails to augment the reno-protective effects of soluble epoxide hydrolase inhibition in streptozotocin-induced diabetic rats via increased 20-HETE levels

The pro-inflammatory cyclooxygenase (COX)-derived prostaglandins and the anti-inflammatory cytochrome P450 epoxygenase-derived epoxyeicosatrienoic acids (EETs) play an important role in the regulation of renal injury. The current study examined whether COX inhibition augments the reno-protective effects of increased EETs levels via inhibiting EETs degradation by soluble epoxide hydrolase (sEH) in diabetic rats. Streptozotocin (50mg/kg, i.v) was used to induce diabetes in male Sprague Dawley rats. Rats were then divided into 5 groups (n=6-8); control non diabetic, diabetic, diabetic treated with the sEH inhibitor trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB), diabetic treated with the COX inhibitor meloxicam and diabetic treated with meloxicam plus t-AUCB for 2 months. Glomerular albumin permeability and urinary albumin and nephrin excretion levels were significantly elevated in diabetic rats together with decreased glomerular α3 integrin and nephrin expression levels. Inhibition of sEH reduced glomerular albumin permeability, albumin and nephrin excretion levels and restored the decrease in glomerular α3 integrin and nephrin expression in diabetic rats. Meloxicam failed to reduce renal injury or even to synergize the reno-protective effects of sEH inhibition in diabetic rats. Furthermore, inhibition of sEH reduced the elevation in renal collagen deposition and urinary MCP-1 excretion levels together with a reduction in the number of renal TUNEL positive cells in diabetic vs. control rats (P<0.05). Meloxicam did not reduce renal inflammation or apoptosis in diabetic rats or even exacerbate the anti-inflammatory and anti-apoptotic effects of sEH inhibition. Renal 20-hydroxyeicosatetranoic acid (20-HETE) levels were elevated in diabetic rats and meloxicam further exacerbated this elevation. In conclusion, our study suggests that inhibition of COX failed to provide renal protection or to augment the reno-protective effects of sEH inhibition in diabetic rats, at least in part, via increased inflammatory 20-HETE levels.

Cyclooxygenase metabolites in the kidney

In the mammalian kidney, prostaglandins (PGs) are important mediators of physiologic processes, including modulation of vascular tone and salt and water. PGs arise from enzymatic metabolism of free arachidonic acid (AA), which is cleaved from membrane phospholipids by phospholipase A2 activity. The cyclooxygenase (COX) enzyme system is a major pathway for metabolism of AA in the kidney. COX are the enzymes responsible for the initial conversion of AA to PGG2 and subsequently to PGH2, which serves as the precursor for subsequent metabolism by PG and thromboxane synthases. In addition to high levels of expression of the "constitutive" rate-limiting enzyme responsible for prostanoid production, COX-1, the "inducible" isoform of cyclooxygenase, COX-2, is also constitutively expressed in the kidney and is highly regulated in response to alterations in intravascular volume. PGs and thromboxane A2 exert their biological functions predominantly through activation of specific 7-transmembrane G-protein-coupled receptors. COX metabolites have been shown to exert important physiologic functions in maintenance of renal blood flow, mediation of renin release and regulation of sodium excretion. In addition to physiologic regulation of prostanoid production in the kidney, increases in prostanoid production are also seen in a variety of inflammatory renal injuries, and COX metabolites may serve as mediators of inflammatory injury in renal disease.

Nonsteroidal Anti-Inflammatory Drugs and the Kidney

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the isoenzymes COX-1 and COX-2 of cyclooxygenase (COX). Renal side effects (e.g., kidney function, fluid and urinary electrolyte excretion) vary with the extent of COX-2-COX-1 selectivity and the administered dose of these compounds. While young healthy subjects will rarely experience adverse renal effects with the use of NSAIDs, elderly patients and those with co-morbibity (e.g., congestive heart failure, liver cirrhosis or chronic kidney disease) and drug combinations (e.g., renin-angiotensin blockers, diuretics plus NSAIDs) may develop acute renal failure. This review summarizes our present knowledge how traditional NSAIDs and selective COX-2 inhibitors may affect the kidney under various experimental and clinical conditions, and how these drugs may influence renal inflammation, water transport, sodium and potassium balance and how renal dysfunction or hypertension may result.

Mechanisms of non-opioid analgesics beyond cyclooxygenase enzyme inhibition

Non-opioid analgesics including both selective and non-selective cyclooxygenase (COX) inhibitors and acetaminophen are the most widely used treatments for pain. Inhibition of COX is thought to be largely responsible for both the therapeutic and adverse effects of this class of drugs. Accumulating evidence over the past two decades has demonstrated effects of non-opioids beyond the inhibition of COX and prostaglandin synthesis that might also explain their therapeutic and adverse effects. These include their interaction with endocannabinoids, nitric oxide, monoaminergic, and cholinergic systems. Moreover, the recent development of microarray technology that allows the study of human gene expression suggests multiple pathways that may be related to the analgesic and anti-inflammatory effects of non-opioids. The present review will discuss the multiple actions of non-opioids and their interactions with these systems during inflammation and pain, suggesting that COX inhibition is an incomplete explanation for the actions of non-opioids and proposes the involvement of multiple selective targets for their analgesic, as well as, their adverse effects.

Prostaglandin EP2 and EP4 receptors modulate expression of the chemokine CCL2 (MCP-1) in response to LPS-induced renal glomerular inflammation

The pro-inflammatory chemokine CCL2 [chemokine (Cys-Cys motif) ligand 2; also known as MCP-1 (monocyte chemotactic protein-1)] is up-regulated in the glomerular compartment during the early phase of LPS (lipopolysaccharide)-induced nephritis. This up-regulation also occurs in cultured MCs (mesangial cells) and is more pronounced in MCs lacking the PGE2 (prostaglandin E2) receptor EP2 or in MCs treated with a prostaglandin EP4 receptor antagonist. To examine a possible feedback mechanism of EP receptor stimulation on CCL2 expression, we used an in vitro model of MCs with down-regulated EP receptor expression. Selectively overexpressing the various EP receptors in these cells then allows the effects on the LPS-induced CCL2 expression to be examined. Cells were stimulated with LPS and CCL2 gene expression was examined and compared with LPS-stimulated, mock-transfected PTGS2 [prostaglandin-endoperoxide synthase 2, also known as COX-2 (cyclo-oxygenase-2)]-positive cells. Overexpression of EP1, as well as EP3, had no effect on LPS-induced Ccl2 mRNA expression. In contrast, overexpression of EP2, as well as EP4, significantly decreased LPS-induced CCL2 expression. These results support the hypothesis that PTGS2-derived prostaglandins, when strongly induced, counter-balance inflammatory processes through the EP2 and EP4 receptors in MCs.

Upregulation of IL-6, IL-8 and CCL2 gene expression after acute inflammation: Correlation to clinical pain

Tissue injury initiates a cascade of inflammatory mediators and hyperalgesic substances including prostaglandins, cytokines and chemokines. Using microarray and qRT-PCR gene expression analyses, the present study evaluated changes in gene expression of a cascade of cytokines following acute inflammation and the correlation between the changes in the gene expression level and pain intensity in the oral surgery model of tissue injury and acute pain. Tissue injury resulted in a significant upregulation in the gene expression of interleukin-6 (IL-6; 63.3-fold), IL-8 (8.1-fold), chemokine (C-C motif) ligand 2 (CCL2; 8.9-fold), chemokine (C-X-C motif) ligand 1 (CXCL1; 30.5-fold), chemokine (C-X-C motif) ligand 2 (CXCL2; 26-fold) and annexin A1 (ANXA1; 12-fold). The upregulation of IL-6 gene expression was significantly correlated to the upregulation of IL-8, CCL2, CXCL1 and CXCL2 gene expression. Interestingly, the tissue injury-induced upregulation of IL-6, IL-8 and CCL2 gene expression, was positively correlated to pain intensity at 3h post-surgery, the onset of acute inflammatory pain. However, ketorolac treatment did not have a significant effect on the gene expression of IL-6, IL-8, CCL2, CXCL2 and ANXA1 at the same time point of acute inflammation. These results demonstrate that the upregulation of IL-6, IL-8 and CCL2 gene expression contributes to the development of acute inflammation and inflammatory pain. The lack of effect of ketorolac on the expression of these gene products may be related to the ceiling analgesic effects of non-steroidal anti-inflammatory drugs.

Roles of Lipid Mediators in Kidney Injury

Small lipids such as eicosanoids exert diverse and complex functions. In addition to their role in regulating normal kidney function, these lipids also play important roles in the pathogenesis of kidney diseases. Increased glomerular cyclooxygenase (COX)1 or COX2 expression has been reported in patients with nephritis and in animal models of nephritis. COX inhibitors have shown beneficial effects on lupus nephritis and passive Heymann nephritis, but not anti-Thy1.1-induced nephritis. 5-Lipoxygenase-derived leukotrienes are involved in inflammatory glomerular injury. Lipoxygenase product 12-hydroxyeicosatetraenoic acid may mediate angiotensin II and transforming growth factor beta-induced mesangial cell abnormality in diabetic nephropathy. P450 arachidonic acid mono-oxygenase-derived 20-hydroxyeicosatetraenoic acid and epoxyeicosatrienoic acids are involved in several forms of kidney injury, including renal injury in metabolic syndrome. Ceramide also has been shown to be an important signaling molecule that is involved in the pathogenesis of acute kidney injury caused by ischemia/reperfusion and toxic insults. Those pathways should provide fruitful targets for intervention in the pharmacologic treatment of renal disease.

Upregulation of cyclooxygenases by retinoic acid in rat mesangial cells

All-trans retinoic acid (ATRA) increases the expression of COX-1 and COX-2 and the production of PGE2, a prostaglandin with anti-inflammatory effects in human mesangial cells (MC). COX-2 increased through a transcriptional mechanism independent of retinoic acid receptors (RAR) and retinoid X receptors (RXR) and dependent on extracellular regulated kinase-1/2 (ERK1/2), that became phosphorylated 5 min after ATRA addition. Here, in rat MC, ATRA also upregulated COX isoenzymes and PGE2 production, but not in the same way as in human MC: (1) PGE2 production increased only slightly; (2) RAR and RXR were involved in the transcriptional upregulation of COX-2 by ATRA since the RAR-pan-antagonist AGN193109 or the RXR-pan-antagonist HX531 abolished the induction of COX-2 mRNA whereas the RAR-pan-agonist TTNPB or the RXR-pan-agonist AGN194204 induced expression of COX-2, and (3) ERK1/2 phosphorylation, though important for COX-2 upregulation, took more than 1 h. Therefore the regulation of COX by ATRA exhibits striking differences between human and rat MC.

Kinase-dependent, retinoic acid receptor-independent up-regulation of cyclooxygenase-2 by all-trans retinoic acid in human mesangial cells

BACKGROUND AND PURPOSE

Preliminary results in human mesangial cells (MC) suggested that all-trans retinoic acid (ATRA) increased the expression of COX-2 and the production of prostaglandin E2 (PGE2), a PG with anti-inflammatory effects in MC. The aim of this work is to confirm that ATRA increases the expression of COX-2 in MC and to examine the mechanisms involved.

EXPERIMENTAL APPROACH

Cultured MC were treated with ATRA. COX expression and kinase activity were analyzed by Western blot. Transcriptional mechanisms were analyzed by Northern blot, RT-PCR and promoter assays.

KEY RESULTS

COX-2 and COX-1 expression and PGE2 production were increased by ATRA. COX-2 played a role in PGE2 production as production was only partially inhibited by COX-1 inhibitor SC-560. COX-2 up-regulation by ATRA was due to transcriptional mechanisms as pre-incubation with actinomycin D abolished it and ATRA increased the expression of COX-2 mRNA and the activity of a human COX-2 promoter construct, whereas post-transcriptional mechanisms were not found. Retinoic acid receptors (RAR) were not involved in the up-regulation of COX-2 by ATRA since it was not inhibited by RAR-pan-antagonists and the RAR-pan-agonist TTNPB did not up-regulate COX-2. Instead ATRA might act through a sustained activation of extracellular signal-regulated kinase 1/2 (ERK1/2) since up-regulation of COX-2 was prevented by inhibition of the activation of ERK1/2 with PD098059. Also ERK1/2, as well as downstream signalling proteins from ERK1/2, remained phosphorylated when COX-2 increased 24 h later.

CONCLUSIONS AND IMPLICATIONS

These results highlight the relevance of RAR-independent mechanisms to the biological effects of ATRA.

Increases in COX II mRNA in the rat spinal cord induced by cauda equina traction

This article investigated the time response of COX II induction by traction of the cauda equina assessed by a quantified RT-PCR method. Under deep GOI anesthesia, male Wistar rats were fixed in the prone position and a laminectomy of the dorsal part of the first and second sacral vertebrae was performed. Following, COX II-mRNA levels in the cervical, thoracic, lumbar, sacral, and caudal segments were measured at 2, 4, 6, and 24 h after traction by a quantified RT-PCR method. After cauda equina traction, significant levels of COX II mRNA were detected in all segments of the spinal cord examined. Maximum levels in each segment were determined 4 h after traction of the cauda equina. Particularly in the sacrocaudal segments significantly higher levels of COX II mRNA were measured 24 h after traction. These results indicate that significant induction of spinal COX II mRNA was caused by cauda equina traction and that such induction plays a regulatory role in the nociceptive pain pathway.

Regulation of monocyte chemoattractant protein 1 (MCP-1) release by explants of human visceral adipose tissue

BACKGROUND

Monocyte chemoattractant protein-1 (MCP-1) is a chemokine involved in monocyte recruitment during inflammation whose plasma level is elevated in obesity.

OBJECTIVE

The present studies were designed to examine the release of MCP-1 in primary culture by explants of visceral adipose tissue from morbidly obese women.

RESULTS

Most of the MCP-1 released by adipose tissue explants was derived from the nonfat cells in adipose tissue. The release of MCP-1 by adipose tissue explants was upregulated almost five-fold between 3 and 48 h of incubation. Approximately half of this upregulation was due to the release of endogenous tumor necrosis factor alpha (TNFalpha) and IL-1beta based on the ability of a combination of a soluble TNFalpha receptor (etanercept) and a blocking antibody against IL-1beta to reduce MCP-1 release. The release of MCP-1 over 48 h was unaffected by insulin or dexamethasone but significantly reduced by the combination of both agents. MCP-1 release was reduced by 60% in the presence of an inhibitor of the nuclear factor kappaB (NF-kappaB) pathway. There were no significant effects of inhibitors of p44/42 mitogen-activated protein kinase (ERK), Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) pathways on MCP-1 release. However, inhibition of MCP-1 release in the presence of inhibitors of both the p38 MAPK and NF-kappaB pathways was greater than that seen with only the NF-kappaB inhibitor.

DISCUSSION

The present data shows that MCP-1 formation is upregulated over a 48-h incubation of primary explants of visceral adipose tissue. Half of this upregulation is dependent upon endogenous TNFalpha and Il-1beta and involves the p38 MAPK and NF-kappaB pathways.

Independent regulation of prostaglandins and monocyte chemoattractant protein-1 by interleukin-1β and hCG in human endometrial cells

BACKGROUND

Inflammatory mediators such as prostaglandins (PG), chemokines, cytokines and their interactions regulate reproductive functions. The relationship between PG and monocyte chemoattractant protein-1 (MCP-1) has not been elucidated in human endometrium. The presence of hCG receptors in the human endometrium suggests that this embryonic signal may exert a local function in this tissue. Our objectives were to investigate the possible association between PG and MCP-1 and to examine the role of hCG in interleukin-1beta (IL-1beta)-regulated PG and MCP-1 production in human endometrium.

METHODS

Primary cell cultures isolated from endometrial biopsies were used as an in vitro model. PG and MCP-1 levels were measured in the culture medium.

RESULTS

IL-1beta stimulates the production of both PG and MCP-1. Neither COX inhibitors nor direct addition of PG affects MCP-1 production. By contrast, MCP-1 is able to induce PGE2 and PGF2alpha in a concentration-dependent manner but it does not appear to contribute to the increase in PG accumulation following IL-1beta stimulation. hCG inhibits IL-1beta-induced PG level. However, hCG has no effect on either basal or IL-1beta-mediated MCP-1 level.

CONCLUSIONS

PG are not involved in the regulation of MCP-1 production in endometrial cells. hCG appears to play a local function in the endometrium.

Renal Cyclooxygenase-2 (Cox-2)

BACKGROUND/AIMS

The role of COX-2 for renal function during renal development, for physiology and pathophysiology of renal diseases and the side effects of available COX-2 inhibitors, has gained increasing interest. We aimed therefore to review the respective role of renal COX-2.

METHODS

Review of relevant recent publications in the field, and in addition of in part unpublished data obtained in our laboratories.

RESULTS

COX-2 is 'constitutively' localized in the kidney i.e. in macula densa, TALH, interstitial cells, and is of utmost importance for normal renal development. Renal COX-2 is regulated by for example sodium and volume intake, angiotensin II, glucocorticoids often involving specific COX-2 promotor response elements. COX-2 derived prostanoids are required for preservation of renal blood flow and glomerular filtration especially in states of fluid deficit, they promote natriuresis, and furthermore may stimulate renin secretion during low-sodium intake/loop diuretic use. Conversely, COX-2 inhibitors decrease glomerular filtration, and renal perfusion, sometimes even causing acute renal failure. In addition, COX-2 inhibitors cause sodium retention, edema formation, cardiac failure and hypertension. The role of COX-2 derived prostanoids in renal inflammation or failure including diabetic nephropathy and renal transplantation remains at present controversial.

CONCLUSION

COX-2 is one of the major players in renal physiology and pathophysiology. One focus of future work should be placed on COX-2 in primary renal diseases.

Celecoxib reduces skin damage after radiation: selective reduction of chemokine and receptor mRNA expression in irradiated skin but not in irradiated mammary tumor

Inflammatory cytokine and chemokine production is mediated, at least in part, by prostaglandin E (PGE2). Cyclooxygenases, COX-1 and COX-2, are two key enzymes in the conversion of arachidonic acid to PGE2. Radiation induces the overproduction of cytokines and chemokines, and it also increases PGE2 production, both locally and systemically. In this study, we tested the effects of a COX-2 inhibitor (celecoxib) after 50 Gy radiation of MCa-35 tumor and cutaneous tissues of C3H/He mice. Preclinical toxicity endpoints and associated alterations in chemokine production and cellular infiltrates were measured. Celecoxib was given by daily gavage (50 mg/kg for 15 days), with the first dose delivered either 2 hours before, 2 days after, or 7 days after a single dose of radiation. Celecoxib-treated animals had less inflammation of the dermis compared with saline-treated controls. Severe skin dermatitis occurred in 23.8% (5/21) of mice treated with 50 Gy, whereas only 17.6%, 5.3%, and 11.1% of mice in the 2-hour pre-, or the 2-day post-, and 7-day postirradiation groups, respectively, had severe dermatitis on day 20. The decreased skin toxicity scores were associated with a reduction of both blood vessels and focal necrosis in MCa-35 tumors. Celecoxib also significantly decreased C-C family chemokine (Rantes and MCP-1) mRNA expression in irradiated skin tissues, but not in tumor tissues, which was accompanied by a decrease in skin mRNA expression of both C-C (CCR2 and CCR5) and C-X-C (CXCR2 and CXCR4) chemokine receptors. A significant positive correlation was also found between skin damage (skin scores) and chemokine and its receptor mRNA expression in radiation-treated mice. Finally, celecoxib also decreased the infiltration of monocytes and neutrophils in locally irradiated tumor and surrounding normal tissue. The differential effects of celecoxib on inflammation help to explain the selective protection by celecoxib of irradiated cutaneous tissues without a concurrent protection of MCa-35 tumors.

Blockade of TGF-beta action ameliorates renal dysfunction and histologic progression in anti-GBM nephritis

BACKGROUND

We tested whether the entire soluble extracellular domain of the human transforming growth factor-beta (TGF-beta) type II receptor, fused to the Fc portion of human immunoglobulin G (IgG1) (Tbeta-ExR) and expressed in skeletal muscles by adenovirus-mediated gene transfer (AdTbeta-ExR), can ameliorate renal dysfunction and histologic progression in a rat experimental anti-glomerular basement membrane (GBM) nephritis.

METHODS

Anti-GBM nephritis was induced in Wistar Kyoto rats by an intravenous injection of anti-rat glomerular basement membrane (GBM) sera. At day 1 (24 hours after induction), AdTbeta-ExR (1 x 109 pfu/mL) was injected into the femoral muscle in the treatment group, and an adenovirus vector-expressing bacterial beta-galactosidase (AdLacZ) was injected into the control group. Then, clinical and histologic changes were examined for 3 weeks after the induction of anti-GBM nephritis.

RESULTS

Tbeta-ExR was detected in the serum at day 7, but the serum concentration of Tbeta-ExR had decreased below the detectable level by day 14. Although blood pressure and the degree of proteinuria were similar in both groups, the deterioration of renal function was significantly blunted in the treatment group. Crescent formation and interstitial fibrosis were also ameliorated in the treatment group. These histologic improvements were accompanied by the decreased interstitial infiltration of macrophages and the decreased alpha-smooth muscle actin (alpha-SMA)-positive cells in the glomeruli and the interstitium.

CONCLUSION

This study demonstrated for the first time that the blockade of TGF-beta action by AdTbeta-ExR in the early stage of anti-GBM nephritis ameliorates the clinical and histologic progression. In addition, this study shed light on the development of a specific gene therapy for human crescentic glomerulonephritis.

Alterations in renal cytosolic phospholipase A2 and cyclooxygenases in polycystic kidney disease

Cytosolic phospholipase A2 (cPLA2), cyclooxygenase-1 (COX-1), and cyclooxygenase-2 (COX-2) regulate the formation of physiologically active prostaglandins, the production of which is known to be elevated in several renal disorders. We studied the relevance of these enzymes in polycystic kidney disease (PKD) by using two models of the disease: a model in which decline in renal function begins in adulthood (CD1-pcy/pcy mouse) and one in which it occurs early, during growth (Han:SPRD-cy rat). Immunoblotting analyses of cytosolic and particulate kidney fractions revealed that cPLA2 levels are significantly higher (by 34-131%) in the latter stages of the disease in both models. Renal COX enzymes were found only in the particulate fractions, with COX-1 87% higher in 6-month-old CD1-pcy/pcy mice compared with normal controls, and 110% higher in male 70-day-old Han:SPRD-cy rats with cystic kidneys compared with controls. Renal COX-2 was detected only in the rats and was 58% lower in diseased kidneys of 70-day-old male Han:SPRD-cy rats, indicating that cPLA2 is coupled to COX-1 in the kidney. The altered levels of these eicosanoid-regulating enzymes has implications for the use of NSAIDS and specific COX inhibitors in individuals with this disorder.

Chronic anti-Thy-1 nephritis is aggravated in the nonclipped but not in the clipped kidney of Goldblatt hypertensive rats

BACKGROUND

We have previously shown that renovascular hypertension does not inhibit healing of the acute Thy-1 nephritis. To test whether a chronic model of the Thy-1 nephritis is more susceptible to high blood pressure, the repetitive hit model was evaluated in rats with 2-kidney, 1-clip Goldblatt hypertension.

METHODS

Six weeks after initiation of 2-kidney, 1-clip hypertension, chronic Thy-1 glomerulonephritis was induced in hypertensive rats by four consecutive injections of rabbit antiserum in weekly intervals. Renal structure and function were examined two weeks after the last injection. Glomerular binding of rabbit IgG as well as expression of transforming growth factor-beta (TGF-beta), alpha-smooth muscle actin (alpha-SMA) and cyclooxygenase (COX)-1 and -2 were evaluated by Western blotting.

RESULTS

Similar glomerular deposition of rabbit IgG was detected in normotensive rats and in both kidneys of Goldblatt hypertensive rats indicating similar delivery and binding of the heterologous antibody. Induction of the repetitive Thy-1 model significantly enhanced glomerular damage in the nonclipped kidney and increased albuminuria. Surprisingly, no glomerular damage developed in the clipped kidney of nephritic hypertensive rats. In contrast, increased glomerular volume and increased expression of TGF-beta, alpha-SMA as well as COX-1 and COX-2 were found in normotensive nephritic rats and in both kidneys of nephritic hypertensive rats.

CONCLUSION

Glomerular and tubulointerstitial damage of the chronic Thy-1 model is dramatically enhanced in the nonclipped kidneys of Goldblatt hypertensive rats. In contrast, the clipped kidney is completely protected from this immunological injury despite similar activation of glomerular cells, induction of TGF-beta, COX-1 and COX-2 and glomerular hypertrophy.

Polarographic behaviour of meloxicam and its determination in tablet preparations and spiked plasma

Meloxicam is a new non-steroidal anti-inflammatory drug (NSAID), which has a higher activity cyclooxygenase-2 (COX-2) than against cyclooxygenase-1 (COX-1), with potentially high anti-inflammatory and analgesic action. The voltammetric behaviour of meloxicam was studied using direct current (DC), differential pulse polarography (DPP) and cyclic voltammetry (CV). The influence of several variables (including nature of the buffer, pH, concentration, modulation amplitude, scan rate, drop size, etc.) was examined in DPP method for meloxicam. The best DPP response was obtained in acetate buffer pH 4.88. The peak currents were measured with a static mercury drop electrode at -1.49 V versus Ag/AgCl. Calibration curve for meloxicam was linear at a concentration range from 0.38 to 15.0 microg ml(-1). The method was validated and applied to the determination of meloxicam in tablets, which were in two different dosage forms. A spectrophotometric method reported in the literature was utilized as a comparison method. There were no significant differences between the results obtained by two methods. DPP method is also available and applicable for the determination of mentioned substance in plasma. Mean recovery was 99.20+/-0.37%. It was concluded that the developed method was accurate, sensitive, precise, reproducible and useful for the quality control of meloxicam in pharmaceuticals and spiked plasma.

Selective cyclooxygenase-2 inhibition impairs glomerular capillary healing in experimental glomerulonephritis

Selective cyclooxygenase-2 (COX-2) inhibitors have anti-inflammatory activity and reduce proteinuria in experimental membranous glomerulonephritis. Antiangiogenic properties of COX-2 inhibitors were recently reported. Whether these properties are relevant to the glomerular healing process in inflammatory glomerular diseases was investigated. For evaluation of the effects of selective COX-2 inhibitors on the glomerular healing process in a rat model of mesangioproliferative glomerulonephritis (induced by anti-Thy 1.1 antibody), a selective COX-2 inhibitor (rofecoxib or celecoxib) or vehicle was administered daily from day 1 after disease induction until euthanasia on day 6. Additional nephritic rats were treated with rofecoxib or vehicle from day 1 to day 10 and were monitored until day 28. Selective COX-2 inhibition led to significant increases in mesangiolysis (up to +71%) on days 2 and 6 and in albuminuria (up to 3.1-fold) on day 6. This augmentation of glomerular capillary damage was associated with rarefaction of glomerular endothelial cells, whereas the proliferation and activation of mesangial cells were not affected. No significant effects on the glomerular influx of polymorphonuclear neutrophils or the infiltration and proliferation of monocytes/macrophages at day 2 were noted. These effects were independent of systemic hemodynamic features, because rofecoxib did not affect systolic BP on day 2 or 5. Nephritic rats treated with rofecoxib for 10 d demonstrated persistent glomerular injury at day 28, as indicated by increased albuminuria (10-fold) and mesangial type IV collagen deposition (+24%). In normal rats, 5-d administration of rofecoxib failed to induce albuminuria or morphologic renal damage. In conclusion, selective COX-2 inhibitors impair glomerular capillary repair after mesangiolysis in rats with anti-Thy 1.1 glomerulonephritis. These data suggest that selective COX-2 inhibitors should be used with caution among patients with inflammatory endocapillary glomerular disorders.

Pharmacology of cyclooxygenase-2 inhibition in the kidney

Cyclooxygenase (COX) exists as two unique isoforms (that is, COX-1 and COX-2) which are poorly understood with regard to their roles in renal function. The renal effects of conventional non-steroidal anti-inflammatory drugs (NSAIDs) are believed to result from the inhibition of one or both isoforms. Drugs that selectively inhibit COX-2 provide useful pharmacological tools for discerning the effects associated with the inhibition of the individual isoforms, and may help clarify the renal roles of COX-1 and COX-2. This review summarizes the current data on the renal expression of COX isoforms and their potential roles in renal function, and reviews the studies that have attempted to correlate renal functional changes with selective isoform inhibition. Since there are significant differences in the expression of COX isoforms in the kidneys of laboratory animals and humans, this review also examines the correlation of the results of COX inhibition in experimental studies in laboratory animals with clinical data. Because of potential interspecies differences in the roles of COX isoforms in renal function, animal models may have limited predictive value for patients, particularly those with renal risk factors. Accordingly, any uncertainty concerning the safety or therapeutic benefit of COX-2-specific drugs in these patient populations will need to be resolved with clinical investigations.

Effect of corticosteroids and eicosapentaenoic acid/docosahexaenoic acid on pro-oxidant and anti-oxidant status and metabolism of essential fatty acids in patients with glomerular disorders

It is known that the concentrations of essential fatty acids and their metabolites including eicosanoids, free radicals and anti-oxidants are altered in glomerular disorders. Both corticosteroids and n-3 fatty acids--eicosapentaenoic acid and docosahexaenoic acid (EPA and DHA respectively)--are useful in the management of glomerular disorders. In the present study, the altered plasma concentrations of lipid peroxides, nitric oxide and the metabolites of essential fatty acids and anti-oxidants--superoxide dismutase, glutathione peroxidase and vitamin E--in the RBC membranes of patients with glomerular disorders (nephrotic syndrome) reverted to normalcy following corticosteroids or EPA/DHA administration. This suggests that the beneficial actions of corticosteroids and EPA/DHA in glomerular disorders can be attributed to their action on the pro-oxidant and anti-oxidant concentrations and metabolism of essential fatty acids.

Cyclopentenone prostaglandins inhibit cytokine-induced nf-kappab activation and chemokine production by human mesangial cells

In the kidney an uncontrolled inflammatory response to an acute insult may lead to chronic inflammation, permanent tissue damage, and progressive renal insufficiency. Resolution of acute inflammation likely is dependent on endogenous regulatory mechanisms activated in parallel with mediators of renal inflammation. These mechanisms are postulated to attenuate the renal expression of proinflammatory cytokines, including the chemokines responsible for recruiting leukocytes to the kidney, thus facilitating the transition from inflammation to healing. To understand the regulation of the inflammatory response within the kidney, the effects of anti-inflammatory J series cyclopentenone prostaglandins on chemokine production by human mesangial cells were examined. Treatment of mesangial cells with prostaglandin J(2) and 15-deoxy-Delta(12,14)-prostaglandin J(2) blocked interleukin-1beta-induced monocyte chemoattractant protein-1 mRNA expression and protein production. This correlated with failure of the transcription factor nuclear factor-kappaB (NF-kappaB) to translocate to the nucleus and bind to its recognition motif, a step required for cytokine-induced monocyte chemoattractant protein-1 gene activation. NF-kappaB failed to translocate because the cyclopentenone prostaglandins attenuated degradation of the NF-kappaB inhibitor IkappaB-alpha. These data suggest that certain prostaglandins can limit the extent of renal chemokine expression and thus may have an important role in resolving renal inflammation.

Monocyte chemoattractant protein-1 and osteopontin differentially regulate monocytes recruitment in experimental glomerulonephritis

BACKGROUND

This study evaluated the mechanisms of monocyte/macrophage (M/M) infiltration in a rat model of anti-glomerular basement membrane glomerulonephritis (GN). We focused on chemokines and osteopontin, which are known regulators of M/M recruitment.

METHODS

Using immunohistology, in situ hybridization, and Northern blotting, the expression levels of chemokines and osteopontin were evaluated in isolated glomeruli and tubules 4, 10, and 20 days after the induction of GN. In vivo blocking experiments were performed by application of neutralizing antibodies against osteopontin and monocyte chemoattractant protein-1 (MCP-1).

RESULTS

In nephritic animals, high glomerular MCP-1 and RANTES (regulated upon activation normal T cell expressed and secreted) expression levels were observed on days 4 and 10. The tubular expression of MCP-1, however, was only slightly enhanced. In contrast, tubular osteopontin production was maximally stimulated (day 10) and paralleled with peaks of albuminuria and tubulointerstitial M/M infiltration. Application of an anti-osteopontin antibody ameliorated tubulointerstitial and glomerular M/M recruitment, whereas treatment with an anti-MCP-1 antibody selectively reduced glomerular M/M recruitment. However, tubulointerstitial M/M infiltration remained unchanged.

CONCLUSION

These studies show that chemokines and osteopontin are differentially expressed in glomeruli and tubules in this model of GN. Chemokines play a primary role in the glomeruli, whereas osteopontin has a predominant role in tubulointerstitial M/M recruitment. The roles of chemokines and osteopontin may thus be dependent on the renal compartment and on the disease model.

Chemokines in renal diseases

The interaction of activated leukocytes and renal resident cells is thought to play a crucial role in the pathogenesis of renal diseases. Recent investigations of the pathophysiological roles of chemokines and their cognate receptors have shed light on the detailed molecular mechanisms of leukocyte trafficking and activation in the diseased kidneys. Chemokine/chemokine receptor systems may be essentially involved in the pathogenesis of phase-specific renal disorders and the measurement of urinary levels of chemokines may be clinically useful for monitoring the different disease phases and activities. In addition, chemokine receptors expressed in renal resident cells may be involved in proliferation, fibrogenesis, as well as chemotaxis. The selective intervention of chemokine/chemokine receptor systems (anti-chemokine therapy) may have the potential as the particular therapeutic strategies for renal diseases in future.

Cyclooxygenase 2 and the kidney

Cyclooxygenase metabolizes arachidonic acid to a family of bioactive fatty acids designated prostaglandins. Two isoforms of cyclooxygenase exist, designated COX1 and COX2. These isoforms are expressed in distinct but important areas of the kidney. COX1 predominates in vascular smooth muscle and collecting ducts, whereas COX2 predominates in the macula densa and nearby cells in the cortical thick ascending limb. COX2 is also highly expressed in medullary interstitial cells. Whereas COX1 expression does not exhibit dynamic regulation, COX2 expression is subject to regulation by several environmental conditions, including salt intake, water intake, medullary tonicity, growth factors, cytokines, and adrenal steroids. Recently, COX2-selective non-steroidal anti-inflammatory drugs have become widely available. Many of the renal effects of non-selective non-steroidal anti-inflammatory drugs (including sodium retention, decreased glomerular filtration rate, and effects on renin-angiotensin levels) appear to be mediated by the inhibition of COX2 rather than COX1. Therefore, in contrast to the gastrointestinal-sparing effects of COX2-selective non-steroidal anti-inflammatory drugs, when considering the kidney, the same caution must be applied when using COX2-selective inhibitors as has been used with traditional non-selective non-steroidal anti-inflammatory drugs.

The Duffy antigen receptor for chemokines is up-regulated during acute renal transplant rejection and crescentic glomerulonephritis

BACKGROUND

Recruitment of leukocytes during immune responses requires the coordinate expression of adhesion molecules in concert with chemokines and their receptors. The Duffy antigen receptor for chemokines (DARC) binds multiple chemokines and is expressed on postcapillary venules in the normal kidney. The chemokine receptor CCR5, which shares the ligand regulated upon activation, normal T-cell expressed and secreted (RANTES) with DARC, is expressed by infiltrating T cells in the renal interstitium. As DARC might be involved in the attraction of CCR5-positive cells, we studied the distribution of DARC and CCR5 in two forms of cell-mediated renal injury: renal allograft rejection and crescentic glomerulonephritis (cGN).

METHODS

A total of 87 renal specimens, including 12 pretransplant biopsies, 47 transplant biopsies (Banff 1, N = 10; Banff 2, N = 19; and various other lesions N = 18), and 28 biopsies from patients with cGN, was analyzed. Immunohistochemistry for CCR5 and DARC was performed on serial sections of formalin-fixed and paraffin-embedded tissue.

RESULTS

Compared with pretransplant biopsies, the mean number of DARC-positive interstitial venules was significantly increased during both transplant rejection and cGN. This was accompanied by an infiltration of CCR5-positive leukocytes. During transplant rejection, the number and distribution of CCR5-positive cells correlated with DARC-positive venules. Infiltrating CCR5-positive leukocytes were found mainly in the interstitium, often clustering around Bowman's capsules in biopsies from cGN. The number of glomerular CCR5 positive cells is low, but they are common in a subset of crescents.

CONCLUSIONS

We hypothesize that the increased number of DARC-positive venules in areas of interstitial injury and the colocalization with CCR5-positive infiltrating leukocytes may indicate a role for endothelial DARC expression during leukocyte adhesion and interstitial infiltration.

Chemokines as therapeutic targets in renal disease

Increased understanding of the fundamental importance of the role of chemokines and their receptors in inflammation, together with the demonstration of their involvement in human and experimental inflammatory renal disease, make these molecules potential therapeutic targets. A number of recent studies using genetically deficient mice and chemokine receptor antagonists in animal models have demonstrated that chemokine inhibition can attenuate experimental renal injury. Because there is simultaneous expression of multiple chemokines and receptors in disease, strategies that are aimed at antagonizing multiple chemokines receptor interactions are likely to be more effective than therapies that target a single chemokine. It is also now recognized that chemokines are involved in normal immune development and immune regulation. These observations, together with the results of studies that have demonstrated deleterious effects of chemokine receptor antagonism in experimental renal disease, highlight the need for thorough understanding of the role of individual chemokines in the pathogenesis of different types of renal disease before optimal therapeutic interventions may be achieved.

A new anti-inflammatory compound, FR167653, ameliorates crescentic glomerulonephritis in Wistar-Kyoto rats

The pathophysiologic effects of FR167653 were investigated in a model of crescentic glomerulonephritis induced by a small dose of nephrotoxic serum in Wistar-Kyoto rats. The rats developed crescentic glomerulonephritis by 6 d after the administration of serum. The subcutaneous administration of FR167653 (32 mg/kg) markedly decreased the severity of the renal damage. In a group of rats treated with FR167653 daily from day 0 to day 6, glomerular damage, including crescent formation and proteinuria, was virtually absent. FR167653 markedly decreased urinary levels of monocyte chemoattractant protein-1 (MCP-1). In addition, FR167653 reduced production of MCP-1 protein and transcripts in the diseased kidneys. In a group of rats for which treatment was initiated on day 3, shortly after the appearance of glomerular abnormalities, the progression of renal disease was appreciably retarded, with partial inhibition of MCP-1. In contrast, when rats were treated only on the first day, no beneficial effects were observed and severe proliferative and necrotizing glomerulonephritis, with crescent formation, was induced by day 6, with the upregulation of MCP-1. These results suggest that FR167653 may be effective against crescentic glomerulonephritis, possibly via the inhibition of MCP-1. In addition, there was marked reduction in renal injury even when FR167653 treatment was initiated after glomerular inflammation was established, suggesting that the therapeutic application of FR167653 may be clinically useful for human renal diseases.

Cellular and molecular mediators in common pathway mechanisms of chronic renal disease progression

Injury mechanisms activated by the hemodynamic adaptations to nephron loss are considered to represent a final common pathway that underlies the progressive nature of chronic renal disease. In this article, we review experimental evidence that the induction of cell adhesion molecule, cytokine and profibrotic growth factor gene expression and the resultant renal infiltration by inflammatory cells, especially macrophages, are important components of these common pathway mechanisms. Interventions aimed at inhibiting these mechanisms may offer new treatments for slowing or arresting the progression of chronic renal disease.

Complement C5b-9-mediated arachidonic acid metabolism in glomerular epithelial cells : role of cyclooxygenase-1 and -2

In the passive Heymann nephritis (PHN) model of membranous nephropathy, complement C5b-9 induces glomerular epithelial cell (GEC) injury and proteinuria, which is partially mediated by eicosanoids. This study addresses the role of cyclooxygenase (COX)-1 and -2 in C5b-9-mediated eicosanoid production in GEC. Unstimulated rat GEC in culture primarily express COX-1. When stimulated with sublytic C5b-9, COX-2 was significantly up-regulated, whereas COX-1 was not affected. Compared with control, complement-treated GEC produced 32% more prostaglandin (PG) E(2) in the presence of exogenous substrate, and the increase was abolished with the COX-2-selective inhibitor, NS-398. Release of arachidonic acid from GEC phospholipids via C5b-9-induced activation of cytosolic phospholipase A(2) was associated with a marked stimulation of PGE(2) production, which was inhibited by 60% with NS-398. The results in cultured GEC were extended to GEC injury in vivo by examining COX-1 and -2 expression in PHN. Glomeruli from rats with PHN expressed significantly more COX-1 and COX-2, as compared with normal rats. PGE(2) production in glomeruli of rats with PHN was about twofold greater than in control glomeruli, and the increase was partially inhibited with NS-398. Thus, in GEC in culture and in vivo, C5b-9-induced eicosanoid production is regulated by both isoforms of COX. The inducible COX-2 may be an important novel mediator of C5b-9-induced glomerular injury.

Chemokine blockade as a therapy for renal disease

Chemokines have been verified as inflammatory mediators of experimental nephritis by using anti-chemokine antibodies, chemokine receptor antagonists or targeted chemokine gene disruption. In human disease, chemokines are expressed in the kidney in association with inflammatory infiltrates. Chemokine blockade is thus a potentially novel approach to therapy of inflammatory renal disease. Several anti-chemokine strategies are under development. Effective use of anti-chemokine therapy for renal disease will require a precise understanding of the unique roles that individual chemokines have in renal pathology, and the genetic factors that regulate chemokine expression.

Chemokines, chemokine receptors, and renal disease: from basic science to pathophysiologic and therapeutic studies

Leukocyte trafficking from peripheral blood into affected tissues is an essential component of the inflammatory reaction to virtually all forms of injury and is an important factor in the development of many kidney diseases. Advances in the past few years have highlighted the central role of a family of chemotactic cytokines called chemokines in this process. Chemokines help to control the selective migration and activation of inflammatory cells into injured renal tissue. Chemokines and their receptors are expressed by intrinsic renal cells as well as by infiltrating cells during renal inflammation. This study summarizes the in vitro and in vivo data on chemokines and chemokine receptors in renal diseases with a special focus on potential therapeutic effects on inflammatory processes.