Ketone flux through BDH1 supports metabolic remodeling of skeletal and cardiac muscles in response to intermittent time-restricted feeding

Time-restricted feeding (TRF) has gained attention as a dietary regimen that promotes metabolic health. This study questioned if the health benefits of an intermittent TRF (iTRF) schedule require ketone flux specifically in skeletal and cardiac muscles. Notably, we found that the ketolytic enzyme beta-hydroxybutyrate dehydrogenase 1 (BDH1) is uniquely enriched in isolated mitochondria derived from heart and red/oxidative skeletal muscles, which also have high capacity for fatty acid oxidation (FAO). Using mice with BDH1 deficiency in striated muscles, we discover that this enzyme optimizes FAO efficiency and exercise tolerance during acute fasting. Additionally, iTRF leads to robust molecular remodeling of muscle tissues, and muscle BDH1 flux does indeed play an essential role in conferring the full adaptive benefits of this regimen, including increased lean mass, mitochondrial hormesis, and metabolic rerouting of pyruvate. In sum, ketone flux enhances mitochondrial bioenergetics and supports iTRF-induced remodeling of skeletal muscle and heart.

Extreme Metastability of Diamond and its Transformation to the BC8 Post-Diamond Phase of Carbon

Diamond possesses exceptional physical properties due to its remarkably strong carbon-carbon bonding, leading to significant resilience to structural transformations at very high pressures and temperatures. Despite several experimental attempts, synthesis and recovery of the theoretically predicted post-diamond BC8 phase remains elusive. Through quantum-accurate multimillion atom molecular dynamics (MD) simulations, we have uncovered the extreme metastability of diamond at very high pressures, significantly exceeding its range of thermodynamic stability. We predict the post-diamond BC8 phase to be experimentally accessible only within a narrow high pressure-temperature region of the carbon phase diagram. The diamond to BC8 transformation proceeds through premelting followed by BC8 nucleation and growth in the metastable carbon liquid. We propose a double-shock compression pathway for BC8 synthesis, which is currently being explored in experiments at the National Ignition Facility.

Circulating Metabolites Associated with Albuminuria in a Hispanic/Latino Population

BACKGROUND

Albuminuria is associated with metabolic abnormalities, but these relationships are not well understood. We studied the association of metabolites with albuminuria in Hispanic/Latino people, a population with high risk for metabolic disease.

METHODS

We used data from 3736 participants from the Hispanic Community Health Study/Study of Latinos, of which 16% had diabetes and 9% had an increased urine albumin-to-creatinine ratio (UACR). Metabolites were quantified in fasting serum through nontargeted mass spectrometry (MS) analysis using ultra-performance liquid chromatography-MS/MS. Spot UACR was inverse normally transformed and tested for the association with each metabolite or combined, correlated metabolites, in covariate-adjusted models that accounted for the study design. In total, 132 metabolites were available for replication in the Hypertension Genetic Epidemiology Network study ( n =300), and 29 metabolites were available for replication in the Malmö Offspring Study ( n =999).

RESULTS

Among 640 named metabolites, we identified 148 metabolites significantly associated with UACR, including 18 novel associations that replicated in independent samples. These metabolites showed enrichment for D-glutamine and D-glutamate metabolism and arginine biosynthesis, pathways previously reported for diabetes and insulin resistance. In correlated metabolite analyses, we identified two modules significantly associated with UACR, including a module composed of lipid metabolites related to the biosynthesis of unsaturated fatty acids and alpha linolenic acid and linoleic acid metabolism.

CONCLUSIONS

Our study identified associations of albuminuria with metabolites involved in glucose dysregulation, and essential fatty acids and precursors of arachidonic acid in Hispanic/Latino population.

PODCAST

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_02_08_CJN09070822.mp3.

The persistent effects of corticosterone administration during lactation on the physiology of maternal and offspring mitochondria

Reproduction and environmental stressors are generally thought to be associated with a cost to the individual experiencing them, but the physiological mechanisms mediating costs of reproduction and maternal effects remain poorly understood. Studies examining the effects of environmental stressors on a female's physiological state and body condition during reproduction, as well as the physiological condition of offspring, have yielded equivocal results. Mitochondrial physiology and oxidative stress have been implicated as important mediators of life-history trade-offs. The goal of this investigation was to uncover the physiological mechanisms responsible for the enhanced trade-off between self-maintenance and offspring investment when an animal is exposed to stressful conditions during reproduction. To that end, we manipulated circulating corticosterone (CORT) levels by orally supplementing lactating female mice with CORT and investigated mitochondrial physiology and oxidative stress of both the reproductive females and their young. We found that maternal CORT exposure resulted in lower litter mass at weaning, but mitochondrial performance and oxidative status of females were not impacted. We also found potential beneficial effects of maternal CORT on mitochondrial function (e.g. higher respiratory control ratio) and oxidative stress (e.g. lower reactive oxygen species production) of offspring in adulthood, suggesting that elevated maternal CORT may be a signal for early-life adversity and prepare the organism with a predictive, adaptive response to future stressors.

Nicotinamide riboside supplementation confers marginal metabolic benefits in obese mice without remodeling the muscle acetyl-proteome

Nicotinamide riboside supplements (NRS) have been touted as a nutraceutical that promotes cardiometabolic and musculoskeletal health by enhancing nicotinamide adenine dinucleotide (NAD⁺) biosynthesis, mitochondrial function, and/or the activities of NAD-dependent sirtuin deacetylase enzymes. This investigation examined the impact of NRS on whole body energy homeostasis, skeletal muscle mitochondrial function, and corresponding shifts in the acetyl-lysine proteome, in the context of diet-induced obesity using C57BL/6NJ mice. The study also included a genetically modified mouse model that imposes greater demand on sirtuin flux and associated NAD⁺ consumption, specifically within muscle tissues. In general, whole body glucose control was marginally improved by NRS when administered at the midpoint of a chronic high-fat diet, but not when given as a preventative therapy upon initiation of the diet. Contrary to anticipated outcomes, the study produced little evidence that NRS increases tissue NAD⁺ levels, augments mitochondrial function, and/or mitigates diet-induced hyperacetylation of the skeletal muscle proteome.

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Dietary NR supplementation (NRS) raises plasma and muscle NAM levels in obese mice

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NRS given post obesity slightly improved glucose control and mitochondrial function

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NRS did not oppose obesity-induced remodeling of the muscle acetyl-proteome

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NRS during weight gain did not protect glucose control and mitochondrial function

Crystal structure of silver pentazolates AgN5 and AgN6

Silver pentazolate, a high energy density compound containing the cyclo-N₅^- anion, has recently been synthesized under ambient conditions. However, due to high sensitivity to irradiation, its crystal structure has not been determined. In this work, silver-nitrogen crystalline compounds under ambient conditions and at high pressures, up to 100 GPa, are predicted and characterized by performing first-principles evolutionary crystal structure searching with variable stoichiometry. It is found that newly discovered AgN₅ and AgN₆ are the only thermodynamically stable silver-nitrogen compounds at pressures between 42 and 80 GPa. In contrast to AgN₅, the pentazolate AgN₆ compound contains N₂ diatomic molecules in addition to cyclo-N₅^-. These AgN₅ and AgN₆ crystals are metastable under ambient conditions with positive formation enthalpies of 54.95 kJ mol^-1 and 46.24 kJ mol^-1, respectively. The underlying cause of the stability of cyclo-N₅^- silver pentazolates is the enhanced aromaticity enabled by the charge transfer from silver atoms to nitrogen rings. To aid in the experimental identification of these materials, calculated Raman spectra are reported at ambient pressure: the frequencies of N₅^- vibrational modes of AgN₅ are in good agreement with those measured in the experiment.

Examination of mercury contamination from a recent coal ash spill into the Dan River, North Carolina, United States

Coal ash spills occasionally occur due to the accidental failure of surface impoundments, and toxic metal-laden ash can pose a serious health threat to adjacent aquatic ecosystems. Here, we performed an investigation into longitudinal variations of mercury (Hg) contamination in the Dan River (North Carolina, United States) about 17 and 29 months after a February 2014 coal ash spill incident, in which the reported Hg concentrations in the spilled coal ash (210 ng/g) were 1-2 orders of magnitude higher than the river sediments (2-61 ng/g). We examined total Hg (THg) and methyl Hg (MeHg) in sediments from 0 to 65 km downstream of the spill, and found that most of the variations of THg and MeHg in surface sediments (0-16 cm) could be well accounted by the organic matter content and appeared to be not contaminated by Hg derived from coal ash. In examining MeHg bioaccumulation in invertebrates (aquatic and riparian) and fish in the Dan River and fish in a reservoir downstream of Dan River, we found no evidence of elevated MeHg bioaccumulation due to the 2014 coal ash spill. Thus, we concluded that Hg contamination from the coal ash spill is largely absent in the Dan River for both surface sediments and biota within the first three years of spill (until 2017), even though the majority of coal ash may be buried deeper in the sediment in the river channel and/or the downstream reservoir. Alternatively, the Hg associated with the coal ash is largely not bioavailable for extensive microbial Hg methylation. The findings provide useful insights into remediation strategies for this incident and other coal ash spills.

Reciprocity Between Skeletal Muscle AMPK Deletion and Insulin Action in Diet-Induced Obese Mice

Insulin resistance due to overnutrition places a burden on energy-producing pathways in skeletal muscle (SkM). Nevertheless, energy state is not compromised. The hypothesis that the energy sensor AMPK is necessary to offset the metabolic burden of overnutrition was tested using chow-fed and high-fat (HF)-fed SkM-specific AMPKα1α2 knockout (mdKO) mice and AMPKα1α2lox/lox littermates (wild-type [WT]). Lean mdKO and WT mice were phenotypically similar. HF-fed mice were equally obese and maintained lean mass regardless of genotype. Results did not support the hypothesis that AMPK is protective during overnutrition. Paradoxically, mdKO mice were more insulin sensitive. Insulin-stimulated SkM glucose uptake was approximately twofold greater in mdKO mice in vivo. Furthermore, insulin signaling, SkM GLUT4 translocation, hexokinase activity, and glycolysis were increased. AMPK and insulin signaling intersect at mammalian target of rapamycin (mTOR), a critical node for cell proliferation and survival. Basal mTOR activation was reduced by 50% in HF-fed mdKO mice, but was normalized by insulin stimulation. Mitochondrial function was impaired in mdKO mice, but energy charge was preserved by AMP deamination. Results show a surprising reciprocity between SkM AMPK signaling and insulin action that manifests with diet-induced obesity, as insulin action is preserved to protect fundamental energetic processes in the muscle.

Mitochondrial physiology varies with parity and body mass in the laboratory mouse (Mus musculus)

The life-history patterns that animals display are a product of their ability to maximize reproductive performance while concurrently balancing numerous metabolic demands. For example, the energetic costs of reproduction may reduce an animal's ability to support self-maintenance and longevity. In this work, we evaluated the impact of parity on mitochondrial physiology in laboratory mice. The theory of mitohormesis suggests that modest exposure to reactive oxygen species can improve performance, while high levels of exposure are damaging. Following this theory, we hypothesized that females that experienced one bout of reproduction (primiparous) would display improved mitochondrial capacity and reduced oxidative damage relative to non-reproductive (nulliparous) mice, while females that had four reproductive events (multiparous) would have lower mitochondrial performance and greater oxidative damage than both nulliparous and primiparous females. We observed that multiple reproductive events enhanced the mitochondrial respiratory capacity of liver mitochondria in females with high body mass. Four-bout females showed a positive relationship between body mass and mitochondrial capacity. In contrast, non-reproductive females showed a negative relationship between body mass and mitochondrial capacity and primiparous females had a slope that did not differ from zero. Other measured variables, too, were highly dependent on body mass, suggesting that a female's body condition has strong impacts on mitochondrial physiology. We also evaluated the relationship between how much females allocated to reproduction (cumulative mass of all young weaned) and mitochondrial function and oxidative stress in the multiparous females. We found that females that allocated more to reproduction had lower basal respiration (state 4), lower mitochondrial density, and higher protein oxidation in liver mitochondria than females that allocated less. These results suggest that, at least through their first four reproductive events, female laboratory mice may experience bioenergetic benefits from reproduction but only those females that allocated the most to reproduction appear to experience a potential cost of reproduction.

An Ecologist’s Guide to Mitochondrial DNA Mutations and Senescence

Longevity plays a key role in the fitness of organisms, so understanding the processes that underlie variance in senescence has long been a focus of ecologists and evolutionary biologists. For decades, the performance and ultimate decline of mitochondria have been implicated in the demise of somatic tissue, but exactly why mitochondrial function declines as individual’s age has remained elusive. A possible source of decline that has been of intense debate is mutations to the mitochondrial DNA. There are two primary sources of such mutations: oxidative damage, which is widely discussed by ecologists interested in aging, and mitochondrial replication error, which is less familiar to most ecologists. The goal of this review is to introduce ecologists and evolutionary biologists to the concept of mitochondrial replication error and to review the current status of research on the relative importance of replication error in senescence. We conclude by detailing some of the gaps in our knowledge that currently make it difficult to deduce the relative importance of replication error in wild populations and encourage organismal biologists to consider this variable both when interpreting their results and as viable measure to include in their studies.

Respiratory Phenomics across Multiple Models of Protein Hyperacylation in Cardiac Mitochondria Reveals a Marginal Impact on Bioenergetics

Acyl CoA metabolites derived from the catabolism of carbon fuels can react with lysine residues of mitochondrial proteins, giving rise to a large family of post-translational modifications (PTMs). Mass spectrometry-based detection of thousands of acyl-PTMs scattered throughout the proteome has established a strong link between mitochondrial hyperacylation and cardiometabolic diseases; however, the functional consequences of these modifications remain uncertain. Here, we use a comprehensive respiratory diagnostics platform to evaluate three disparate models of mitochondrial hyperacylation in the mouse heart caused by genetic deletion of malonyl CoA decarboxylase (MCD), SIRT5 demalonylase and desuccinylase, or SIRT3 deacetylase. In each case, elevated acylation is accompanied by marginal respiratory phenotypes. Of the >60 mitochondrial energy fluxes evaluated, the only outcome consistently observed across models is a ∼15% decrease in ATP synthase activity. In sum, the findings suggest that the vast majority of mitochondrial acyl PTMs occur as stochastic events that minimally affect mitochondrial bioenergetics.

SIRT2 knockout exacerbates insulin resistance in high fat-fed mice

The NAD+-dependent deacetylase SIRT2 is unique amongst sirtuins as it is effective in the cytosol, as well as the mitochondria. Defining the role of cytosolic acetylation state in specific tissues is difficult since even physiological effects at the whole body level are unknown. We hypothesized that genetic SIRT2 knockout (KO) would lead to impaired insulin action, and that this impairment would be worsened in HF fed mice. Insulin sensitivity was tested using the hyperinsulinemic-euglycemic clamp in SIRT2 KO mice and WT littermates. SIRT2 KO mice exhibited reduced skeletal muscle insulin-induced glucose uptake compared to lean WT mice, and this impairment was exacerbated in HF SIRT2 KO mice. Liver insulin sensitivity was unaffected in lean SIRT2 KO mice. However, the insulin resistance that accompanies HF-feeding was worsened in SIRT2 KO mice. It was notable that the effects of SIRT2 KO were largely disassociated from cytosolic acetylation state, but were closely linked to acetylation state in the mitochondria. SIRT2 KO led to an increase in body weight that was due to increased food intake in HF fed mice. In summary, SIRT2 deletion in vivo reduces muscle insulin sensitivity and contributes to liver insulin resistance by a mechanism that is unrelated to cytosolic acetylation state. Mitochondrial acetylation state and changes in feeding behavior that result in increased body weight correspond to the deleterious effects of SIRT2 KO on insulin action.

Integrin-Linked Kinase Is Necessary for the Development of Diet-Induced Hepatic Insulin Resistance

The liver extracellular matrix (ECM) expands with high-fat (HF) feeding. This finding led us to address whether receptors for the ECM, integrins, are key to the development of diet-induced hepatic insulin resistance. Integrin-linked kinase (ILK) is a downstream integrin signaling molecule involved in multiple hepatic processes, including those related to differentiation, wound healing, and metabolism. We tested the hypothesis that deletion of ILK in mice on an HF diet would disrupt the ECM-integrin signaling axis, thereby preventing the transformation into the insulin-resistant liver. To determine the role of ILK in hepatic insulin action in vivo, male C57BL/6J ILK^lox/lox mice were crossed with Albcre mice to produce a hepatocyte-specific ILK deletion (ILK^lox/loxAlbcre). Results from this study show that hepatic ILK deletion has no effect on insulin action in lean mice but sensitizes the liver to insulin during the challenge of HF feeding. This effect corresponds to changes in the expression and activation of key insulin signaling pathways as well as a greater capacity for hepatic mitochondrial glucose oxidation. This demonstrates that ILK contributes to hepatic insulin resistance and highlights the previously undefined role of integrin signaling in the pathogenesis of diet-induced hepatic insulin resistance.

Integrin-Linked Kinase in Muscle Is Necessary for the Development of Insulin Resistance in Diet-Induced Obese Mice

Diet-induced muscle insulin resistance is associated with expansion of extracellular matrix (ECM) components, such as collagens, and the expression of collagen-binding integrin, α2β1. Integrins transduce signals from ECM via their cytoplasmic domains, which bind to intracellular integrin-binding proteins. The integrin-linked kinase (ILK)-PINCH-parvin (IPP) complex interacts with the cytoplasmic domain of β-integrin subunits and is critical for integrin signaling. In this study we defined the role of ILK, a key component of the IPP complex, in diet-induced muscle insulin resistance. Wild-type (ILK(lox/lox)) and muscle-specific ILK-deficient (ILK(lox/lox)HSAcre) mice were fed chow or a high-fat (HF) diet for 16 weeks. Body weight was not different between ILK(lox/lox) and ILK(lox/lox)HSAcre mice. However, HF-fed ILK(lox/lox)HSAcre mice had improved muscle insulin sensitivity relative to HF-fed ILK(lox/lox) mice, as shown by increased rates of glucose infusion, glucose disappearance, and muscle glucose uptake during a hyperinsulinemic-euglycemic clamp. Improved muscle insulin action in the HF-fed ILK(lox/lox)HSAcre mice was associated with increased insulin-stimulated phosphorylation of Akt and increased muscle capillarization. These results suggest that ILK expression in muscle is a critical component of diet-induced insulin resistance, which possibly acts by impairing insulin signaling and insulin perfusion through capillaries.

SIRT3 Is Crucial for Maintaining Skeletal Muscle Insulin Action and Protects Against Severe Insulin Resistance in High-Fat-Fed Mice

Protein hyperacetylation is associated with glucose intolerance and insulin resistance, suggesting that the enzymes regulating the acetylome play a role in this pathological process. Sirtuin 3 (SIRT3), the primary mitochondrial deacetylase, has been linked to energy homeostasis. Thus, it is hypothesized that the dysregulation of the mitochondrial acetylation state, via genetic deletion of SIRT3, will amplify the deleterious effects of a high-fat diet (HFD). Hyperinsulinemic-euglycemic clamp experiments show, for the first time, that mice lacking SIRT3 exhibit increased insulin resistance due to defects in skeletal muscle glucose uptake. Permeabilized muscle fibers from HFD-fed SIRT3 knockout (KO) mice showed that tricarboxylic acid cycle substrate-based respiration is decreased while fatty acid-based respiration is increased, reflecting a fuel switch from glucose to fatty acids. Consistent with reduced muscle glucose uptake, hexokinase II (HKII) binding to the mitochondria is decreased in muscle from HFD-fed SIRT3 KO mice, suggesting decreased HKII activity. These results show that the absence of SIRT3 in HFD-fed mice causes profound impairments in insulin-stimulated muscle glucose uptake, creating an increased reliance on fatty acids. Insulin action was not impaired in the lean SIRT3 KO mice. This suggests that SIRT3 protects against dietary insulin resistance by facilitating glucose disposal and mitochondrial function.

Exercise and the Regulation of Hepatic Metabolism

The accelerated metabolic demands of the working muscle cannot be met without a robust response from the liver. If not for the hepatic response, sustained exercise would be impossible. The liver stores, releases, and recycles potential energy. Exercise would result in hypoglycemia if it were not for the accelerated release of energy as glucose. The energetic demands on the liver are largely met by increased oxidation of fatty acids mobilized from adipose tissue. Adaptations immediately following exercise facilitate the replenishment of glycogen stores. Pancreatic glucagon and insulin responses orchestrate the hepatic response during and immediately following exercise. Like skeletal muscle and other physiological systems, liver adapts to repeated demands of exercise by increasing its capacity to produce energy by oxidizing fat. The ability of regular physical activity to increase fat oxidation is protective and can reverse fatty liver disease. Engaging in regular physical exercise has broad ranging positive health implications including those that improve the metabolic health of the liver.

The extracellular matrix and insulin resistance

The extracellular matrix (ECM) is a highly-dynamic compartment that undergoes remodeling as a result of injury and repair. Over the past decade, mounting evidence in humans and rodents suggests that ECM remodeling is associated with diet-induced insulin resistance in several metabolic tissues. In addition, integrin receptors for the ECM have also been implicated in the regulation of insulin action. This review addresses what is currently known about the ECM, integrins, and insulin action in the muscle, liver, and adipose tissue. Understanding how ECM remodeling and integrin signaling regulate insulin action may aid in the development of new therapeutic targets for the treatment of insulin resistance and type 2 diabetes (T2D).

Integrin α1-null mice exhibit improved fatty liver when fed a high fat diet despite severe hepatic insulin resistance

Hepatic insulin resistance is associated with increased collagen. Integrin α1β1 is a collagen-binding receptor expressed on hepatocytes. Here, we show that expression of the α1 subunit is increased in hepatocytes isolated from high fat (HF)-fed mice. To determine whether the integrin α1 subunit protects against impairments in hepatic glucose metabolism, we analyzed glucose tolerance and insulin sensitivity in HF-fed integrin α1-null (itga1(-/-)) and wild-type (itga1(+/+)) littermates. Using the insulin clamp, we found that insulin-stimulated hepatic glucose production was suppressed by ∼50% in HF-fed itga1(+/+) mice. In contrast, it was not suppressed in HF-fed itga1(-/-) mice, indicating severe hepatic insulin resistance. This was associated with decreased hepatic insulin signaling in HF-fed itga1(-/-) mice. Interestingly, hepatic triglyceride and diglyceride contents were normalized to chow-fed levels in HF-fed itga1(-/-) mice. This indicates that hepatic steatosis is dissociated from insulin resistance in HF-fed itga1(-/-) mice. The decrease in hepatic lipid accumulation in HF-fed itga1(-/-) mice was associated with altered free fatty acid metabolism. These studies establish a role for integrin signaling in facilitating hepatic insulin action while promoting lipid accumulation in mice challenged with a HF diet.

Exacerbated inflammatory arthritis in response to hyperactive gp130 signalling is independent of IL-17A

Objective

Interleukin (IL)-17A producing CD4 T-cells (T_H-17 cells) are implicated in rheumatoid arthritis (RA). IL-6/STAT3 signalling drives T_H-17 cell differentiation, and hyperactive gp130/STAT3 signalling in the gp130^F/F mouse promotes exacerbated pathology. Conversely, STAT1-activating cytokines (eg, IL-27, IFN-γ) inhibit T_H-17 commitment. Here, we evaluate the impact of STAT1 ablation on T_H-17 cells during experimental arthritis and relate this to IL-17A-associated pathology.

Methods

Antigen-induced arthritis (AIA) was established in wild type (WT), gp130^F/F mice displaying hyperactive gp130-mediated STAT signalling and the compound mutants gp130^F/F:Stat1^−/− and gp130^F/F:Il17a^−/− mice. Joint pathology and associated peripheral T_H-17 responses were compared.

Results

Augmented gp130/STAT3 signalling enhanced T_H-17 commitment in vitro and exacerbated joint pathology. Ablation of STAT1 in gp130^F/F mice (gp130^F/F:Stat1^−/−) promoted the hyperexpansion of T_H-17 cells in vitro and in vivo during AIA. Despite this heightened peripheral T_H-17 cell response, disease severity and the number of joint-infiltrating T-cells were comparable with that of WT mice. Thus, gp130-mediated STAT1 activity within the inflamed synovium controls T-cell trafficking and retention. To determine the contribution of IL-17A, we generated gp130^F/F:IL-17a^−/− mice. Here, loss of IL-17A had no impact on arthritis severity.

Conclusions

Exacerbated gp130/STAT-driven disease in AIA is associated with an increase in joint infiltrating T-cells but synovial pathology is IL-17A independent.

Contractile, but not endothelial, dysfunction in early inflammatory arthritis: a possible role for matrix metalloproteinase-9

BACKGROUND AND PURPOSE

Excess morbidity/mortality in rheumatoid arthritis (RA) is associated with increased incidence of cardiovascular disease. In this 'proof-of-concept' study, vascular function was characterized in the murine collagen-induced arthritis (mCIA) model, the benchmark choice for evaluation of the pathological processes and assessment of new therapies.

EXPERIMENTAL APPROACH

Mice in the very early stages of arthritis development [and appropriate naïve (non-immunized) age-matched controls] were used in the study. Blood pressure was measured using tail cuff plethysmography. Vascular function in rings of isolated aorta was studied with isometric tension myography. Levels of NO metabolites (NO(x)), MMP-9 protein and IL-1β in plasma and MMP-9 protein in aortic homogenates were quantified.

KEY RESULTS

Impaired vascular contractile responses in arthritis were unaffected by ex vivo inhibition of NOS (endothelial/neuronal and inducible) or COX activities. Endothelium-dependent and -independent relaxation, plasma NO(x) and blood pressure were unaffected by arthritis. Plasma and aortic homogenate MMP-9 protein levels were increased significantly in arthritis. Incubation of aortic tissues from naïve control animals with exogenous MMP-9 impaired subsequent contractile responses, mirroring that observed in arthritis. A role for IL-1β in perpetuating contractile dysfunction and increasing aortic MMP-9 was excluded.

CONCLUSIONS AND IMPLICATIONS

These data identify for the first time a relationship between early arthritis and contractile dysfunction and a possible role for MMP-9 therein, in the absence of overt endothelial dysfunction or increased NO production. As such, MMP-9 may constitute a significant target for early intervention in RA patients with a view to decreasing risk of cardiovascular disease.

Permanent genetic resources added to Molecular Ecology Resources Database 1 August 2010-30 September 2010

This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis × Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross-tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.

Role of Rho kinase isoforms in murine allergic airway responses

Inhibition of Rho-associated coiled-coil forming kinases (ROCKs) reduces allergic airway responses in mice. The purpose of this study was to determine the roles of the two ROCK isoforms, ROCK1 and ROCK2, in these responses. Wildtype (WT) mice and heterozygous ROCK1 and ROCK2 knockout mice (ROCK1(+/-) and ROCK2(+/-), respectively) were sensitised and challenged with ovalbumin. ROCK expression and activation were assessed by western blotting. Airway responsiveness was measured by forced oscillation. Bronchoalveolar lavage was performed and the lungs were fixed for histological assessment. Compared with WT mice, ROCK1 and ROCK2 expression were 50% lower in lungs of ROCK1(+/-) and ROCK2(+/-) mice, respectively, without changes in the other isoform. In WT lungs, ROCK activation increased after ovalbumin challenge and was sustained for several hours. This activation was reduced in ROCK1(+/-) and ROCK2(+/-) lungs. Airway responsiveness was comparable in WT, ROCK1(+/-), and ROCK2(+/-) mice challenged with PBS. Ovalbumin challenge caused airway hyperresponsiveness in WT, but not ROCK1(+/-) or ROCK2(+/-) mice. Lavage eosinophils and goblet cell hyperplasia were significantly reduced in ovalbumin-challenged ROCK1(+/-) and ROCK2(+/-) versus WT mice. Ovalbumin-induced changes in lavage interleukin-13, interleukin-5 and lymphocytes were also reduced in ROCK1(+/-) mice. In conclusion, both ROCK1 and ROCK2 are important in regulating allergic airway responses.

Effects of quercetin and EGCG on mitochondrial biogenesis and immunity

PURPOSE

To test the influence of 1000 mg of quercetin (Q) with or without 120 mg of epigallocatechin 3-gallate (EGCG), 400 mg of isoquercetin, and 400 mg of eicosapentaenoic acid and docosahexaenoic acid (Q-EGCG) on exercise performance, muscle mitochondrial biogenesis, and changes in measures of immunity and inflammation before and after a 3-d period of heavy exertion.

METHODS

Trained cyclists (N = 39) were randomized to placebo (P), Q, or Q-EGCG and ingested supplements in a double-blinded fashion for 2 wk before, during, and 1 wk after a 3-d period in which subjects cycled for 3 h x d(-1) at approximately 57% Wmax. Blood, saliva, and muscle biopsy samples were collected before and after 2 wk of supplementation and immediately after the exercise bout on the third day. Blood and saliva samples were also collected 14 h after exercise.

RESULTS

Two-week supplementation resulted in a significant increase in plasma quercetin for Q and Q-EGCG and granulocyte oxidative burst activity (GOBA) in Q-EGCG. Immediately after the third exercise bout, significant decreases for C-reactive protein (CRP), and plasma interleukin 6 (IL-6) and interleukin 10 (IL-10) were measured in Q-EGCG compared with P. Granulocyte colony-stimulating factor and CRP were reduced in Q-EGCG 14 h after exercise. No group differences were measured in muscle messenger RNA expression for peroxisome proliferator-activated receptor gamma coactivator alpha, citrate synthase, or cytochrome c.

CONCLUSIONS

Two-week supplementation with Q-EGCG was effective in augmenting GOBA andin countering inflammation after 3 d of heavy exertion in trained cyclists.

Hybridization of leucyl-transfer ribonucleic Acid isoacceptors from green leaves with nuclear and chloroplast deoxyribonucleic Acid

Chromatographically distinct isoacceptors of leucyl-tRNA from mature bean leaves were all observed to hybridize with bean chloroplast and nuclear DNA in a ratio similar to that exhibited by the unfractionated leucyl-tRNA. Under the same hybridization conditions, maize tRNA failed to form a stable hybrid with bean DNA, and levels of hybridization between bean-leaf leucyl-tRNA and nuclear or chloroplast DNAs from tobacco and maize were relatively small.

Quercetin's influence on exercise performance and muscle mitochondrial biogenesis

PURPOSE

To determine the influence of 2 wk of quercetin (Q; 1000 mg x d(-1)) compared with placebo (P) supplementation on exercise performance and skeletal muscle mitochondrial biogenesis in untrained, young adult males (N = 26, age = 20.2 +/- 0.4 yr, VO2max = 46.3 +/- 1.2 mL x kg(-1) x min(-1)).

METHODS

Using a randomized, crossover design with a 2-wk washout period, subjects provided blood and muscle biopsy samples presupplementation and postsupplementation periods and were given 12-min time trials on 15% graded treadmills after 60 min of moderate exercise preloads at 60% VO2max.

RESULTS

Plasma Q levels rose significantly in Q versus P during the 2-wk supplementation period (interaction P value <0.001). During the 12-min trial, the net change in distance achieved was significantly greater during Q (2.9%) compared with P (-1.2%; 29.5 +/- 11.5 vs -11.9 +/- 16.0 m, respectively, P = 0.038). Skeletal muscle messenger RNA expression tended to increase (range = 16-25%) during Q versus P for sirtuin 1 (interaction effect, P = 0.152), peroxisome proliferator-activated receptor gamma coactivator-1alpha (P = 0.192), cytochrome c oxidase (P = 0.081), and citrate synthase (P = 0.166). Muscle mitochondrial DNA (relative copy number per diploid nuclear genome) increased 140 +/- 154 (4.1%) with Q compared with -225 +/- 157 (6.0% decrease) with P (P = 0.098).

CONCLUSIONS

In summary, 1000 mg x d(-1) Q versus P for 2 wk by untrained males was associated with a small but significant improvement in 12-min treadmill time trial performance and modest but insignificant increases in the relative copy number of mitochondrial DNA and messenger RNA levels of four genes related to mitochondrial biogenesis.

Modulation of ozone-induced airway hyperresponsiveness and inflammation by interleukin-13

The present study aimed to determine whether the T-helper cell type 2-derived cytokines, interleukin (IL)-4 and -13, can modulate the lung response to ozone exposure. IL-13(-/-), IL-4/13(-/-) and IL-13-overexpressing transgenic (Tg) mice were exposed to ozone (3 ppm; 3 h) or air. Wild-type (Wt) Balb/c mice and transgenic-negative littermates (IL-13Wt) were used as controls for gene-deficient and IL-13Tg mice, respectively. IL-4/13(-/-) and IL-13(-/-) mice developed a lesser degree of ozone-induced airway hyperresponsiveness (AHR) while IL-13Tg mice developed a greater degree of AHR compared with ozone-exposed wild-type or IL-13Wt mice, respectively. Ozone caused a time-dependent increase of bronchoalveolar lavage (BAL) neutrophils and macrophages in wild-type mice, maximal at 20-24 h, which was attenuated in the IL-13(-/-) and IL-4/13(-/-) mice. In IL-13Tg mice, there was a greater increase in BAL neutrophils after ozone exposure compared with IL-13Wt mice. Using quantitative real-time PCR, ozone-induced mRNA expression for IL-6 and keratinocyte chemokine was further enhanced in IL-13(-/-) and IL-4/13(-/-) mice, and was inhibited in IL-13Tg mice. Macrophage inflammatory protein (MIP)-3alpha/CCL20 expression was enhanced after ozone exposure in wild-type mice, inhibited in IL-13(-/-) and IL-4/13(-/-) mice, while in IL-13Tg mice it was enhanced. A similar pattern of expression was observed with lipopolysaccharide-induced cytokine (LIX/CXCL5/ENA-78) expression. In conclusion, interleukin-13 augments ozone-induced airway hyperresponsiveness and neutrophilic inflammation, possibly through modulation of certain cytokines induced by ozone exposure.

Interleukin-1beta induced activation of nuclear factor-kappab can be inhibited by novel pharmacological agents in osteoarthritis

OBJECTIVES

To investigate the importance of activation of the transcription factor, nuclear factor-kappaB (NF-kappaB) by interleukin-1beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha) in the pathogenesis of osteoarthritis (OA) and assess its suitability as a target for therapy by determining its role in the induction of the cytokine IL-6 and the degenerative enzymes, matrix metalloproteinase (MMP)-1 and MMP-3 in vitro.

METHODS

Three distinct cellular models, derived from primary OA tissue, were employed, namely, fibroblast-like synoviocytes (OA-SF); co-cultures containing phenotypic macrophage-like and fibroblast-like cells (OA-COCUL); and primary OA synovial tissue explants (OA-EXP). These were treated with specific inhibitors of IL-1beta, TNF-alpha and NF-kappaB to assess their differential role in the production of pathologically relevant mediators, specifically IL-6, MMP-1, MMP-3 and the tissue inhibitor of metalloproteinases-1 (TIMP-1), which were quantified by enzyme-linked immunosorbent assay.

RESULTS

Inhibition of NF-kappaB by a novel agent, RO100 at a dose of 0.1 microM, exerted significant (P < 0.05) repression of IL-6, MMP-1 and MMP-3 production in OA-SF. Notably, neither TIMP-1 production nor cell viability was significantly affected at the dose tested. These data were reproduced in OA-EXP, which might be considered as having greater physiological relevance. Interestingly, comparable efficacy was noted using IL-1beta and TNF-alpha neutralizing antibodies in OA-COCUL.

CONCLUSIONS

We have demonstrated that a novel pharmacological inhibitor of NF-kappaB, RO100 inhibits pathological mediators of OA progression with equivalent efficacy as established IL-1beta and TNF-alpha neutralizing strategies. Our findings highlight a potential for developing NF-kappaB targeted therapeutics for positively regulating disease activity and improving clinical outcome in OA.

Deletion of the gene encoding CD59a in mice increases disease severity in a murine model of rheumatoid arthritis

OBJECTIVE

To investigate the roles of CD59a in the protection of joint tissue in the context of murine antigen-induced arthritis (AIA).

METHODS

AIA was triggered in CD59a-deficient (CD59a(-/-)) mice and in CD59a-sufficient (CD59a(+/+)) controls; the course and severity of disease were compared between groups. The effects on arthritis of restoring CD59 to the joint in CD59a(-/-) mice by use of a membrane-targeted recombinant CD59 were also explored.

RESULTS

Disease, as assessed clinically by measurement of joint swelling on day 1 (P < 0.0001), day 2 (P < 0.01), and day 7 (P < 0.02) and histologically from indicators of joint damage on day 21 (P < 0.02), was significantly enhanced in CD59a(-/-) mice compared with CD59a(+/+) wild-type controls. Membrane attack complex (MAC) deposition in the arthritic joints of CD59a(-/-) mice was also increased compared with that in the joints of CD59a(+/+) controls. Restitution of CD59 activity in joints of CD59a(-/-) mice was attempted with soluble recombinant rat CD59 (sCD59) or with a novel membrane-targeted rat CD59 derivative (sCD59-APT542). Strong immunohistochemical staining of the synovial membrane and subsynovial tissue was apparent in sCD59-APT542-injected joints, but not in joints injected with untargeted sCD59. Intraarticular administration of sCD59-APT542 markedly ameliorated disease severity in CD59a(-/-) mice, knee swelling was significantly reduced over the time course of the disease, and joint damage, assessed histologically, was significantly milder on day 21 (P < 0.05).

CONCLUSION

These data firmly implicate the MAC of complement as a major effector of joint damage in the murine AIA model of rheumatoid arthritis (RA), and they provide a rationale for the inhibition of MAC assembly as a therapeutic strategy for RA.

Nitrite inhibits hydrogen production and kills the cattle parasite Tritrichomonas foetus

AIMS

To investigate the effects of NaNO2 on the microaerophilic flagellated protozoan, Tritrichomonas foetus KV1, an economically important cattle parasite that inhabits the vagina and can spread rapidly through herds of animals by sexual transmission and leads to abortion of foetal calves.

METHODS AND RESULTS

Growth of the parasite was inhibited by 50% in the presence of 4 mm NaNO2; immediate killing occurred at 10 mm. Mass spectrometric monitoring of gases showed that H2 and CO2 evolution were inhibited by NaNO2, and electron paramagnetic resonance spectrometry revealed a signal similar to that of a thiolate-iron-NO complex. Growth with sublethal concentrations of NaNO2 yielded organisms that produced ethanol rather than H2.

CONCLUSIONS

NaNO2 probably inactivates FeS protein(s) of hydrogenosomes so as to inhibit the conversion of pyruvate (derived from maltose in the growth medium) to H2 and acetate.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of NaNO2 as a topical antitrichomonal agent in veterinary practice is a possibility. At present, slaughter of infected animals is the favoured method of control.

Coupling complement regulators to immunoglobulin domains generates effective anti-complement reagents with extended half-life in vivo

Complement activation and subsequent generation of inflammatory molecules and membrane attack complex contributes to the pathology of a number of inflammatory and degenerative diseases, including arthritis, glomerulonephritis and demyelination. Agents that specifically inhibit complement activation might prove beneficial in the treatment of these diseases. Soluble recombinant forms of the naturally occurring membrane complement regulatory proteins (CRP) have been exploited for this purpose. We have undertaken to design better therapeutics based on CRP. Here we describe the generation of soluble, recombinant CRP comprising rat decay accelerating factor (DAF) or rat CD59 expressed as Fc fusion proteins, antibody-like molecules comprising two CRP moieties in place of the antibody Fab arms (CRP-Ig). Reagents bearing DAF on each arm (DAF-Ig), CD59 on each arm (CD59-Ig) and a hybrid reagent containing both DAF and CD59 were generated. All three reagents inhibited C activation in vitro. Compared with soluble CRP lacking Fc domains, activity was reduced, but was fully restored by enzymatic release of the regulator from the Ig moiety, implicating steric constraints in reducing functional activity. In vivo studies showed that DAF-Ig, when compared to soluble DAF, had a much extended half-life in the circulation in rats and concomitantly caused a sustained reduction in plasma complement activity. When given intra-articularly to rats in a model of arthritis, DAF-Ig significantly reduced severity of disease. The data demonstrate the potential of CRP-Ig as reagents for sustained therapy of inflammatory disorders, including arthritis, but emphasize the need for careful design of fusion proteins to retain function.

Suppression of chronic streptococcal cell wall-induced arthritis in Lewis rats by liposomal clodronate

OBJECTIVES

To investigate the role of macrophages in the pathogenesis of chronic streptococcal cell wall (SCW)-induced arthritis using liposomal clodronate.

METHODS

Female Lewis rats with SCW-induced arthritis received a single intravenous injection of 20 mg of clodronate encapsulated within small unilamellar vesicles (SUVc) 10 days post-arthritis induction.

RESULTS

SUVc significantly suppressed the development of chronic SCW-induced arthritis for up to 26 days after treatment. At this time point, ED1(+) macrophages were significantly depleted in the liver and ankle joints, although splenic macrophage numbers were not significantly different from control groups. Macrophage elimination induced a significant reduction in local levels of interleukin (IL)-1beta, IL-6, tumour necrosis factor-alpha (TNFalpha) and matrix metalloproteinase-9 (MMP-9) from ankle joints.

CONCLUSIONS

Macrophage elimination by SUVc inhibits local production of IL-1beta, IL-6, TNFalpha and MMP-9, and the pathogenesis of inflammatory arthritis.

Amelioration of rat antigen-induced arthritis by liposomally conjugated methotrexate is accompanied by down-regulation of cytokine mRNA expression

OBJECTIVES

We examined the temporal changes in the expression of interleukin 1beta (IL-1beta), tumour necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) in the rat antigen-induced arthritis (AIA) model and investigated how their expression was modulated following disease amelioration by liposomally conjugated methotrexate (G-MLV).

METHODS

On the day of arthritis induction (day 0), rats were treated with a single intra-articular injection of G-MLV, methotrexate (MTX), a dose of lipid equivalent to G-MLV (E-LIPO) or saline. On days 3 and 7 after disease induction, animals from each experimental group were killed. Joint tissue was examined histologically and for mRNA expression (IL-6, IL-1beta and TNF-alpha) using semiquantitative reverse transcription-polymerase chain reaction.

RESULTS

There was no significant difference (ANOVA) in knee swelling between MTX-, E-MLV- or saline-treated animals from day 0 to day 7. By day 1, G-MLV significantly reduced knee swelling (1.94+/-0.12 mm; P<0.0001) compared with rats treated with MTX (3.17+/-0.18 mm). G-MLV treatment also significantly inhibited the histological progression of AIA. This reduction in disease severity was accompanied by a reduction in IL-1beta mRNA expression in synovial tissue extracts on day 3 and IL-6 mRNA expression on both day 3 and day 7.

CONCLUSIONS

Liposomally conjugated MTX may exert its beneficial effects in experimental arthritis through IL-1beta and IL-6 inhibition.

Therapeutic efficacy of a novel membrane-targeted complement regulator in antigen-induced arthritis in the rat

OBJECTIVE

Complement system activation is strongly implicated as a factor in the pathogenesis of chronic synovitis in human rheumatoid arthritis. The objective of this study was to explore the therapeutic potential and local retention of a novel membrane-targeting complement regulatory protein, derived from human complement receptor 1, in the experimental setting of rat antigen-induced arthritis.

METHODS

Sensitized animals were treated at the time of arthritis induction with a single intraarticular (IA) dose of the membrane-targeting regulator APT070, a non-membrane-targeting control regulator (APT898), or vehicle control, and disease was assessed clinically and histologically. In addition, immunocytochemical analysis was performed on sections from normal rat knee joints at various time points after IA injection with APT070.

RESULTS

Animals treated with APT070 showed a dose-dependent therapeutic effect, with significantly milder clinical and histologic disease compared with both other treatment groups (P < 0.008 at the higher dose) and minimal evidence of erosive disease at study end in the active treatment group. Immunoperoxidase and immunofluorescence studies demonstrated local retention of APT070 on cell surface membranes within the normal joint up to 48 hours after IA injection.

CONCLUSION

These results show that IA complement inhibition represents an effective therapeutic strategy in experimental arthritis, by demonstrating that the exogenous delivery of a membrane-targeting complement regulator can result in prolonged synovial cell surface binding and significant clinical benefit in vivo. Complement inhibitory strategies of this type should be considered as novel therapies in human inflammatory arthritis.

Soluble complement receptor one (sCR1) inhibits the development and progression of rat collagen-induced arthritis

We set out to determine whether inhibition of complement using sCR1 could influence the development and progression of collagen arthritis in the Lewis rat. Collagen arthritis was successfully established in the Lewis rat, using a novel immunization schedule. In separate experiments, cobra venom factor (CVF) and sCR1 were used to achieve systemic complement inhibition. Their respective effects on disease onset and on the progression of established disease compared with saline-treated control animals was explored. Arthritis was assessed by measurement of clinical score, paw diameter and paw volume. Complement inhibition using either CVF or sCR1, prior to the onset of clinical signs of inflammation, delayed the development of disease. CVF was ineffective in the treatment of established disease, whereas sCR1 delayed the progression of disease in affected joints and prevented the recruitment of further joints while the animals were complement-depleted. In the control saline-treated groups the disease continued to progress relentlessly. We conclude that complement activation is important in the initiation and maintenance of inflammation in collagen arthritis. The potent disease-modulating effect of sCR1 provides persuasive evidence that specific complement inhibiting agents may be an effective approach to the treatment of inflammatory joint diseases

Pro-inflammatory effects of the aminobisphosphonate ibandronate in vitro and in vivo

OBJECTIVES

To investigate the effects of the aminobisphosphonate, ibandronate, on the course of joint inflammation in rat antigen-induced arthritis (AIA) and the release of pro-inflammatory cytokines in partially purified human peripheral blood mononuclear cells (PBMC).

METHODS

Rats with AIA received a single intra-articular injection of ibandronate (1 mg) 7 days post-arthritis induction and knee swelling was measured for 7 days thereafter. The effects of ibandronate (300 microg/ml) on PBMC cytokine production and activation marker expression were determined using polymerase chain reaction (PCR)/ELISA and FACS analysis, respectively.

RESULTS

Joint swelling, associated with AIA, was sustained in ibandronate-treated rats compared with saline-treated control rats. Ibandronate stimulated the production of interferon gamma (IFN-gamma) in adherent PBMC, and increased the surface expression of FcgammaRI and HLA DP, DQ, DR on the adherent monocyte population. Activation by lipopolysaccharide (LPS) of PBMC previously incubated with ibandronate led to enhanced levels of tumour necrosis factor alpha (TNF-alpha) secretion, and this could be partially inhibited by neutralizing antibodies to IFN-gamma.

CONCLUSIONS

The enhanced production of TNF-alpha by ibandronate-treated PBMC in vitro involves stimulation of adherent monocytes by IFN-gamma prior to LPS-induced activation. Similar cellular interactions may be involved in the pro-inflammatory effects of ibandronate in vivo.

Liposomal clodronate eliminates synovial macrophages, reduces inflammation and ameliorates joint destruction in antigen-induced arthritis

OBJECTIVES

To investigate the efficacy of a single i.v. dose of clodronate encapsulated within small unilamellar vesicles in suppressing joint inflammation and the histological progression of rat antigen-induced arthritis (AIA).

METHODS

Rats with AIA received a single i.v. injection of 20 mg of clodronate encapsulated within small unilamellar vesicles (SUVc) or larger multilamellar vesicles (MLVc) 7 days post-arthritis induction. Free clodronate or saline were used as negative controls.

RESULTS

SUVc was shown to be more effective than MLVc, sustaining a significant reduction in knee swelling for up to 7 days after the initial systemic administration. Knee swelling in free clodronate-treated animals was not significantly affected. The increased efficacy of SUVc in reducing inflammation and joint destruction was associated with a significant depletion of resident ED1+, ED2+ and ED3+ macrophages from the synovial membrane (SM).

CONCLUSIONS

SUVc is more efficient than MLVc in reducing the severity of inflammation and joint destruction in rat AIA, and is associated with the specific elimination of macrophage subpopulations from the SM.

Interleukin-1beta (IL-1beta) inhibition: a possible mechanism for the anti-inflammatory potency of liposomally conjugated methotrexate formulations in arthritis

1. Liposomes with conventional and long-circulation times were employed as carriers for the methotrexate derivative MTX-gamma-DMPE (MTX-EPC and MTX-PEG respectively), their mechanism of action was investigated in vitro and in vivo and their therapeutic efficacy assessed using the rat collagen-induced arthritis (CIA) model. 2. At non-toxic dose, both MTX-EPC and MTX-PEG inhibited the lipopolysaccharide (LPS) induced release of IL-1beta from activated rat peritoneal macrophages (rPMPhi) in a dose and time dependent manner. Free methotrexate (MTX) was not active in this respect. After a single intravenous injection (i.v.), and at equivalent doses, both free MTX (500 microg) and MTX-EPC inhibited the LPS induced rise in plasma IL-1beta levels observed in MTX-PEG and saline treated rats. 3. When used to treat established CIA, MTX-EPC resulted in significantly lower clinical score (CS) (1.0+/-0.42 (P<0.001)) and hind paw diameter (HPD) (6.5+/-0.34 mm (P<0.001)) measurements than controls (3.0+/-0.26; 7.33+/-0.41 mm), after only two i.v. doses, and remained significantly lower for the entire experimental period. By day 24 both CS (2+/-0.61 (P<0.001)) and HPD (6.97+/-0.25 mm (P<0.002)) measurements had also become significantly lower in MTX-PEG treated rats than in saline treated controls (3.62+/-0.17, 7. 92+/-0.38 mm) and remained lower until day 30. Joint inflammation in MTX treated rats was completely ameliorated by day 20 but the health and well being of the animals was compromised and the experiment terminated at this time-point. 4. Our results clearly demonstrate that both MTX-EPC and MTX-PEG liposomes have potential for development into therapeutic modalities for the treatment of inflammatory joint disease in man.

Intracellular measurement of prostaglandin E2: effect of anti-inflammatory drugs on cyclooxygenase activity and prostanoid expression

Cyclooxygenase (COX) converts arachidonic acid to prostaglandin (PG) H2, which is further metabolized to various prostaglandins, prostacyclin and thromboxane A2. COX exists in at least two different isoforms. COX-1 is constitutively expressed, whereas COX-2 is induced by proinflammatory stimuli. Prostaglandin E2 is a major metabolite of COX activation. In order to compare the activity of target ligands and COX inhibitors on PGE2 synthesis and release, the responsiveness of several cell lines to the calcium ionophore A23187, bacterial lipopolysaccharide (LPS), nonsteroidal anti-inflammatory drugs (NSAIDs), and the glucocorticoid, dexamethasone, were investigated. For intracellular measurements, the culture supernatant was aspirated, and the cells were thoroughly washed and lysed with dodecyltrimethylammonium bromide. Intracellular and secreted PGE2 were measured with an enzyme immunoassay. A23187 and LPS increased intracellular PGE2 in a dose-dependent manner. Kinetic experiments with A23187-stimulated mouse 3T3 fibroblast cells revealed a distinct biphasic response in COX activity. In the presence of NSAIDs or dexamethasone, there was a dose-dependent inhibition in intracellular PGE2 with A23187-stimulated 3T3 cells. Inhibitory studies demonstrated an apparent increased sensitivity of COX activity to the action of inhibitors when measuring intracellular PGE2 compared with using cell culture supernatants. Indeed, intracellular PGE2 levels were comprehensively reduced in the presence of low concentrations of inhibitor. The utilization of cell culture lysates and, in particular, measurement of intracellular PGE2 should prove useful for identifying new COX inhibitors.

7-Oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridines as novel inhibitors of human eosinophil phosphodiesterase

High-throughput file screening against inhibition of human lung PDE4 led to the discovery of 3-ethyl-1-(4-fluorophenyl)-6-phenyl-7-oxo-4, 5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine (11) as a novel PDE4 inhibitor. Subsequent SAR development, using an eosinophil PDE assay, led to analogues up to 50-fold more potent than 11 with IC50 values of 0.03-1.6 microM. One such compound, CP-220,629 (22) (IC50 = 0.44 microM), was efficacious in the guinea pig aerosolized antigen induced airway obstruction assay (ED50 2.0 mg/kg, po) and demonstrated a significant reduction in eosinophil (55%), neutrophil (65%), and IL-1beta (82%) responses to antigen challenge in atopic monkeys (10 mg/kg, po).

A group for the adult daughters of mentally ill mothers: looking backwards and forwards

A closed time-limited therapy group was conducted for four women who had all been raised by mentally ill mothers. Themes recurring frequently included hatred of self and mother, current lack of extended family support, current parenting difficulties, ongoing stigma and isolation. All group members perceived themselves as troubled despite others' perceptions of them as resilient. The results for the individuals treated are outlined using clinical material, as statistical analysis was not undertaken. All were able to cease individual therapy. Conclusions focus on the benefits of such a group process of recognition and affirmation of the profound consequences of a mother's mental illness on her daughters and thence to grandchildren. The possibility of primary prevention using techniques from infant-parent and child-group therapy is discussed.

Local therapy with soluble complement receptor 1 (sCR1) suppresses inflammation in rat mono-articular arthritis

Complement activation has been implicated in the pathogenesis of human rheumatoid arthritis. We sought to determine whether inhibition of complement (C) using sCR1 could influence the development and progression of antigen arthritis in the rat, a recognized model of human chronic synovitis. The effect of C inhibition, systemically and locally, on three different stages of disease was examined: (i) prophylaxis, (ii) treatment of established inflammation, and (iii) prevention of antigen-induced flares of disease. Arthritis was assessed by knee swelling and by histological examination. Our results show that intra-articular injection of sCR1 prior to disease onset reduced joint swelling and development of arthritis, whereas systemic administration was ineffective. Treatment of established arthritis with intraarticular sCR1 3 days after disease onset caused a transient reduction in swelling, but treatment 7 days after disease onset had no effect on disease. An intra-articular dose of sCR1 given at the time of disease flares had a small, yet significant effect on knee swelling. We conclude that complement activation is important in the initiation and maintenance of inflammation in antigen arthritis. The potent effect of local C inhibition suggests that C biosynthesis and activation within the joint contributes to inflammation in this model of arthritis.

The isolation and characterization of a novel G protein-coupled receptor regulated by immunologic challenge

Using a degenerate PCR based approach, a fragment of the novel G protein-coupled receptor, VTR 15-20, was identified from the rat ventral tegmentum. Hybridization screening and RACE PCR were employed to isolate the full length clone. The cDNA encodes a protein of 305 amino acids which shares homology to several orphan as well as known G protein-coupled receptors. Amino acid analysis demonstrates the VTR 15-20 contains specific regions conserved among the G protein-coupled receptor superfamily. Messenger RNA encoding VTR 15-20 is expressed throughout the mammalian nervous system. Using primary rat culture systems we have demonstrated the expression of VTR 15-20 mRNA in both microglia and astrocytes. The highest levels of VTR 15-20 mRNA expression are detected in peripheral tissues including the spleen. Moreover, we have found that the expression of VTR 15-20 mRNA in brain and spleen is regulated by immunologic challenge. Based on the cellular distribution and regulation by immune challenge and neuronal insult, we hypothesize that VTR 15-20 plays a role in neuroimmune function.

Trabeculectomy with intraoperative 5-fluorouracil vs mitomycin C

PURPOSE

To compare the effectiveness of intraoperative 5-fluorouracil (5-FU) and mitomycin C used adjunctively with trabeculectomy in a black West African population.

METHODS

Eighty-five consecutive eyes of 85 black patients undergoing primary trabeculectomy for open-angle glaucoma were prospectively randomly assigned to receive either 5-FU (50 mg/ml for 5 minutes) or mitomycin C (0.5 mg/ml for 3 1/2 minutes) intraoperatively by soaked sponge.

RESULTS

Of the 81 eyes with at least a 3-month postoperative follow-up, 41 of 44 (93.2%) in the mitomycin C group and 27 of 37 (73.0%) in the 5-FU group had a final intraocular pressure of less than 21 mm Hg (P = .01). Twenty-eight of 44 eyes (63.6%) in the mitomycin C group and 18 of 37 (51.4%) in the 5-FU group had a final intraocular pressure of less than 15 mm Hg (P = .26). Mean postoperative intraocular pressure was 13.7 mm Hg in the mitomycin C group and 16.3 mm Hg in the 5-FU group (P = .05). There were no differences between the two groups in mean age, preoperative intraocular pressure, postoperative visual acuity, and complications. Mean follow-up was 10.0 +/- 4.41 months (range, 4 to 19 months).

CONCLUSIONS

The adjunctive use of mitomycin C with trabeculectomy is equally safe and more efficacious compared to 5-FU in this West African population. Use of mitomycin C in this study was not associated with a statistically significantly greater proportion of patients achieving low intraocular pressure (less than 15 mm Hg) compared to 5-FU.