Study of femoral component malrotation as a cause of pain after total knee arthroplasty

INTRODUCTION

The total knee arthroplasty (TKA) has been shown to be a successful and cost-benefit procedure in terms of pain improvement in patient with symptomatic knee osteoarthritis. However, almost a 20% of the patients are not satisfied with the result of the surgery.

MATERIAL AND METHOD

We have carried out a transversal unicentric cases controls study with clinical cases of the own hospital, obtained by a clinical records revision. A total of 160 patients with a TKA with at least 1year of follow-up were selected. Demographic variables, functional scales (WOMAC and VAS) and rotation of the femoral component through the analysis of the images obtained by CT scan were collected.

RESULTS

The total was 133 patients that was divided in two groups. A control group and pain group. The control group was made up of 70 patients with a mean age of 69.59years (23 men and 47 women) and the pain group was made up of 63 patients with a mean age of 69.48years (13 men and 50 women). We did not found difference regarding the analysis of the rotation of the femoral component. In addition, we were not found significant differences when applying a stratification by sex. The analysis of the malrotation of the femoral component, previously defining limits of value rotation considered as extreme, in any of the case did not show significant differences.

CONCLUSION

The results of the study confirm that malrotation of the femoral component had no influence on the presence of pain at a minimum of one year of follow-up after TKA implantation.

[Translated article] Study of femoral component malrotation as a cause of pain after total knee arthroplasty

INTRODUCTION

The total knee arthroplasty (TKA) has been shown to be a successful and cost-benefit procedure in terms of pain improvement in patient with symptomatic knee osteoarthritis. However, almost a 20% of the patients are not satisfied with the result of the surgery.

MATERIAL AND METHOD

We have carried out a transversal unicentric cases controls study with clinical cases of the own hospital, obtained by a clinical records revision. A total of 160 patients with a TKA with at least 1 year of follow-up were selected. Demographic variables, functional scales (WOMAC and VAS) and rotation of the femoral component through the analysis of the images obtained by CT scan were collected.

RESULTS

The total was 133 patients that was divided in two groups. A control group and pain group. The Control group was made up of 70 patients with a mean age of 69.59 years (23 men and 47 women) and the pain group was made up of 63 patients with a mean age of 69.48 years (13 men and 50 women). We didn't find difference regarding the analysis of the rotation of the femoral component. In addition, we were not found significant differences when applying a stratification by sex. And, the analysis of the malrotation of the femoral component, previously defining limits of value rotation considered as extreme, in any of the case did not show significant differences.

CONCLUSION

The results of the study confirm that malrotation of the femoral component had no influence on the presence of pain at a minimum of one year of follow-up after TKA implantation.

Sexual pheromone modulates the frequency of cytosolic Ca2+ bursts in Saccharomyces cerevisiae

Transient and highly regulated elevations of cytosolic Ca²⁺ control a variety of cellular processes. Bulk measurements using radioactive Ca²⁺ and the luminescent sensor aequorin have shown that in response to pheromone, budding yeast cells undergo a rise of cytosolic Ca²⁺ that is mediated by two import systems composed of the Mid1-Cch1-Ecm7 protein complex and the Fig1 protein. Although this response has been widely studied, there is no treatment of Ca²⁺ dynamics at the single-cell level. Here, using protein calcium indicators, we show that both vegetative and pheromone-treated yeast cells exhibit discrete and asynchronous Ca²⁺ bursts. Most bursts reach maximal amplitude in 1-10 s, range between 7 and 30 s, and decay in a way that fits a single-exponential model. In vegetative cells, bursts are scarce but preferentially occur when cells are transitioning G1 and S phases. On pheromone presence, Ca²⁺ burst occurrence increases dramatically, persisting during cell growth polarization. Pheromone concentration modulates burst frequency in a mechanism that depends on Mid1, Fig1, and a third, unidentified, import system. We also show that the calcineurin-responsive transcription factor Crz1 undergoes nuclear localization bursts during the pheromone response.

Dual effects of β3 integrin subunit expression on human pancreatic cancer models

Background: Pancreatic cancer, the fifth leading cause of adult cancer death in Western countries, lacks early detection, and displays significant dissemination ability. Accumulating evidence shows that integrin-mediated cell attachment to the extracellular matrix induces phenotypes and signaling pathways that regulate tumor cell growth and migration.

Methods: In view of these findings, we examined the role of β₃ in pancreatic cancer by generating two stable β₃-expressing pancreatic human cell lines and characterizing their behavior in vitro and in vivo.

Results: Transduction of β₃ selectively augmented the functional membrane αvβ₃ integrin levels, as evident from the enhanced adhesion and migration abilities related to active Rho GTPases. No effects on in vitro anchorage-dependent growth, but higher anoikis were detected in β₃-overexpressing cells. Moreover, tumors expressing β₃ displayed reduced growth. Interestingly, treatment of mice with an αv-blocking antibody inhibited the growth of β₃-expressing tumors to a higher extent.

Conclusion: Our results collectively support the hypothesis that αvβ₃ integrin has dual actions depending on the cell environment, and provide additional evidence on the role of integrins in pancreatic cancer, which should eventually aid in improving prediction of the effects of therapies addressed to modulate integrin activities in these tumors.

Activation of the cell wall integrity pathway promotes escape from G2 in the fungus Ustilago maydis

It is widely accepted that MAPK activation in budding and fission yeasts is often associated with negative effects on cell cycle progression, resulting in delay or arrest at a specific stage in the cell cycle, thereby enabling cells to adapt to changing environmental conditions. For instance, activation of the Cell Wall Integrity (CWI) pathway in the budding yeast Saccharomyces cerevisiae signals an increase in CDK inhibitory phosphorylation, which leads cells to remain in the G2 phase. Here we characterized the CWI pathway of Ustilago maydis, a fungus evolutionarily distant from budding and fission yeasts, and show that activation of the CWI pathway forces cells to escape from G2 phase. In spite of these disparate cell cycle responses in S. cerevisiae and U. maydis, the CWI pathway in both organisms appears to respond to the same class cell wall stressors. To understand the basis of such a difference, we studied the mechanism behind the U. maydis response. We found that activation of CWI pathway in U. maydis results in a decrease in CDK inhibitory phosphorylation, which depends on the mitotic phosphatase Cdc25. Moreover, in response to activation of the CWI pathway, Cdc25 accumulates in the nucleus, providing a likely explanation for the increase in the unphosphorylated form of CDK. We also found that the extended N-terminal domain of Cdc25, which is dispensable under normal growth conditions, is required for this G2 escape as well as for resistance to cell wall stressors. We propose that the process of cell cycle adaptation to cell stress evolved differently in these two divergent organisms so that each can move towards a cell cycle phase most appropriate for responding to the environmental signals encountered.

Spa2 is required for morphogenesis but it is dispensable for pathogenicity in the phytopathogenic fungus Ustilago maydis

The increasing evidence linking regulation of polar growth and pathogenicity in fungi has elicited a significant effort devoted to produce a better understanding of mechanisms determining polarization in pathogenic fungi. Here we characterize in the phytopathogenic basidiomycete Ustilago maydis, the Spa2 protein, a well-known component of polarisome, firstly described in Saccharomyces cerevisiae. U. maydis display a dimorphic switch between budding growth of hapoid cells and filamentous growth of the dikaryon. During yeast growth, a GFP-tagged Spa2 protein localized to distinct growth sites in a cell cycle-specific manner, while during hyphal growth is persistently located to hyphal tips. Deletion of spa2 gene produces rounder budding cells and thicker filaments than wild-type cells, suggesting a role of Spa2 for the determination of the growth area in U. maydis. We also address the connections between Spa2 and the actin- and microtubule-cytoskeleton. We found that the absence of Spa2 does not affect cytoskeleton organization and strikingly, interference with actin filament or microtubule formation does not affect the polar localization of Spa2. In contrast, defects in the small GTPase Rac1 seems to affect the ability of Spa2 to locate to precise sites at the tip cell. Finally, to our surprise, we found that cells defectives in Spa2 function were as pathogenic as wild-type cells.

Optimized preclinical models for human pancreatic adenocarcinoma therapy research

15019

Background: Efforts to find new therapies for human pancreatic ductal adenocarcinoma (PDAC) have not resulted in clear improvements on patient survival. Better knowledge of resistance mechanisms and redefiniton of molecular targets is essential to design more efficient therapies. The multifactorial origin of PDAC points to combined strategies as the therapy of choice, though the effective development of such strategies is hampered by the lack of optimal preclinical models. We have generated and validated optimized human PDAC models by direct implantation of fresh tumoral tissue into the pancreas of athymic mice. Methods: Thirteen pancreatic adenocarcinoma specimens from PDAC patients were obtained by surgical resection. From each specimen, several 10 mg-fragments were used to generate the corresponding intrapancreatic xenografted tumours. Eleven human PDAC orthotopic models have been successfully generated and perpetuated by succesive passages (up to 4). Histological and molecular analyses of both primary and xenografted tumors have been performed by tissue- array, western-blot and DNA sequentiation. Results: Initial engraftment rate ranged from 20 to 100% (mean 59%) and it improved with succesive passages (mean 76% at second and 90% at third generation). Ki67 expression and degree of differentiation in primary tumors correlated with xenograft growth kinetics. Furthermore, their spontaneous metastatic behaviour fairly reproduced the original patient dissemination patterns. Xenografted tumors kept the original architecture and expression patterns of common PDAC markers. Efficacy of several agents was tested on different xenografted tumors, validating this model and underlining its utility to define future therapeutic strategies for drug development and clinical trials. Conclusions: The orthotopic models described here are, probably, the closest resemblance to a patient clinical setting since they preserve human pancreatic structures, genotypic features and biological behaviour. From their use, biological relevant data could be drawn for future clinical trials and for testing new agents and new drug combinations since they represent, very likely, the most reliable animal models at present.

No significant financial relationships to disclose.

Pathocycles: Ustilago maydis as a model to study the relationships between cell cycle and virulence in pathogenic fungi

Activation of virulence in pathogenic fungi often involves differentiation processes that need the reset of the cell cycle and induction of a new morphogenetic program. Therefore, the fungal capability to modify its cell cycle constitutes an important determinant in carrying out a successful infection. The dimorphic fungus Ustilago maydis is the causative agent of corn smut disease and has lately become a highly attractive model in addressing fundamental questions about development in pathogenic fungi. The different morphological and genetic changes of U. maydis cells during the pathogenic process advocate an accurate control of the cell cycle in these transitions. This is why this model pathogen deserves attention as a powerful tool in analyzing the relationships between cell cycle, morphogenesis, and pathogenicity. The aim of this review is to summarize recent advances in the unveiling of cell cycle regulation in U. maydis. We also discuss the connection between cell cycle and virulence and how cell cycle control is an important downstream target in the fungus-plant interaction.

Mice lacking TNFalpha receptors 1 and 2 are resistant to death and fulminant liver injury induced by agonistic anti-Fas antibody

The liver is particularly susceptible to Fas-mediated cytotoxicity. Mice given an adequate parenteral dose of agonistic anti-Fas antibody (aFas) or of FasL are known to develop a devastating liver injury and to die in a few hours. The present work shows that mice lacking TNFR1 and TNFR2 (R(-)) both survive a single dose of aFas, otherwise rapidly lethal, and develop a mild form of hepatic damage, compared to the much more severe liver injury that in a few hours strikes wild-type mice (R(+)), eventually involving increased activity of proteases of different families (caspase 3-, 8-, and 9-like, calpains, cathepsin B). Neither the overall tissue levels of Fas and FasL nor Fas expression at the hepatocyte surface are altered in the liver of R(-) animals. The DNA-binding activity of the NF-kappaB transcription factor is enhanced after aFas treatment, but much more markedly in R(-) than in R(+) mice. Bcl2, while unchanged in untreated animals, is markedly upregulated in R(-) but not in R(+) mice challenged with aFas. The requirement of a normal TNFR1/TNFR2 phenotype for full deployment of the general and liver-specific aFas toxicity in mice most likely implies that treatment with aFas in some way results in activation of the TNFalpha-TNFRs system and that this activation synergizes with Fas-mediated signals in causing the fulminant liver injury and the animal death. The precise cellular and molecular details underlying this interplay between Fas- and TNFRs-mediated signaling systems in the general and liver-specific aFas toxicity largely remain to be clarified.

Increased tumour necrosis factor-alpha plasma levels during moderate-intensity exercise in COPD patients

Post-training downregulation of muscle tumour necrosis factor (TNF)-alpha messenger ribonucleic acid (mRNA) expression and decrease in cellular TNF-alpha levels have been reported in the elderly. It is hypothesised that chronic obstructive pulmonary disease (COPD) patients may not show these adaptations due to their reduced ability to increase muscle antioxidant capacity with training. Eleven COPD patients (forced expiratory volume in one second 40 +/- 4.4% of the predicted value) and six age-matched controls were studied. Pre- and post-training levels of TNF-alpha, soluble TNF receptors (sTNFRs: sTNFR55 and sTNFR75) and interleukin (IL)-6 in plasma at rest and during exercise and vastus lateralis TNF-alpha mRNA were examined. Moderate-intensity constant-work-rate exercise (11 min at 40% of pretraining peak work-rate) increased pretraining plasma TNF-alpha levels in COPD patients (from 17 +/- 3.2 to 23 +/- 2.7 pg x mL(-1); p<0.005) but not in controls (from 19 +/- 4.6 to 19 +/- 3.2 pg x mL(-1)). No changes were observed in sTNFRs or IL-6 levels. After 8 weeks' endurance training, moderate-intensity exercise increased plasma TNF-alpha levels similarly to pretraining (from 16 +/- 3 to 21 +/- 4 pg x mL(-1); p<0.01). Pretraining muscle TNF-alpha mRNA expression was significantly higher in COPD patients than in controls (29.3 +/- 13.9 versus 5.0 +/- 1.5 TNF-alpha/18S ribonucleic acid, respectively), but no changes were observed after exercise or training. It is concluded that moderate-intensity exercise abnormally increases plasma tumour necrosis factor-alpha levels in chronic obstructive pulmonary disease patients without exercise-induced upregulation of the tumour necrosis factor-alpha gene in skeletal muscle.

TNF-alpha is involved in activating DNA fragmentation in skeletal muscle

Intraperitoneal administration of 100 microg kg(-1) (body weight) of tumour necrosis factor-alpha to rats for 8 consecutive days resulted in a significant decrease in protein content, which was concomitant with a reduction in DNA content. Interestingly, the protein/DNA ratio was unchanged in the skeletal muscle of the tumour necrosis factor-alpha-treated animals as compared with the non-treated controls. Analysis of muscle DNA fragmentation clearly showed enhanced laddering in the skeletal muscle of tumour necrosis factor-alpha-treated animals, suggesting an apoptotic phenomenon. In a different set of experiments, mice bearing a cachexia-inducing tumour (the Lewis lung carcinoma) showed an increase in muscle DNA fragmentation (9.8-fold) as compared with their non-tumour-bearing control counterparts as previously described. When gene-deficient mice for tumour necrosis factor-alpha receptor protein I were inoculated with Lewis lung carcinoma, they were also affected by DNA fragmentation; however the increase was only 2.1-fold. These results suggest that tumour necrosis factor-alpha partly mediates DNA fragmentation during experimental cancer-associated cachexia.

Reduced muscle redox capacity after endurance training in patients with chronic obstructive pulmonary disease

The present study was undertaken to test whether endurance training in patients with COPD, along with enhancement of muscle bioenergetics, decreases muscle redox capacity as a result of recurrent episodes of cell hypoxia induced by high intensity exercise sessions. Seventeen patients with COPD (FEV(1), 38 +/- 4% pred; PaO2), 69 +/- 2.7 mm Hg; PaCO2, 42 +/- 1.7 mm Hg) and five age-matched control subjects (C) were studied pretraining and post-training. Reduced (GSH) and oxidized (GSSG) glutathione, lipid peroxidation, and gamma-glutamyl cysteine synthase heavy subunit chain mRNA expression (gammaGCS-HS mRNA) were measured in the vastus lateralis. Pretraining redox status at rest and after moderate (40% Wpeak) constant-work rate exercise were similar between groups. After training (DeltaWpeak, 27 +/- 7% and 37 +/- 18%, COPD and C, respectively) (p < 0.05 each), GSSG levels increased only in patients with COPD (from 0.7 +/- 0.08 to 1.0 +/- 0.15 nmol/ mg protein, p < 0.05) with maintenance of GSH levels, whereas GSH markedly increased in C (from 4.6 +/- 1.03 to 8.7 +/- 0.41 nmol/ mg protein, p < 0.01). Post-training gammaGCS-HS mRNA levels increased after submaximal exercise in patients with COPD. No evidence of lipid peroxidation was observed. We conclude that although endurance training increased muscle redox potential in healthy subjects, patients with COPD showed a reduced ability to adapt to endurance training reflected in lower capacity to synthesize GSH.

Hyperlipemia: a role in regulating UCP3 gene expression in skeletal muscle during cancer cachexia?

Rats bearing the Yoshida AH-130 ascites hepatoma showed an increased expression of both uncoupling protein-2 (UCP2) (two-fold) and UCP3 (three- to four-fold) in skeletal muscle (both soleus and gastrocnemius). The increase in mRNA content was associated with increased circulating concentrations of fatty acids (two-fold), triglyceride (two-fold) and cholesterol (1.9-fold). Administration of nicotinic acid to tumor-bearing rats abolishes the hyperlipidemic increase associated with tumor burden. The vitamin treatment also resulted in a decreased UCP3 gene expression in soleus muscle but not in gastrocnemius. It is concluded that circulating fatty acids may be involved in the regulation of UCP3 gene expression in aerobic muscles during experimental cancer cachexia. Since the UCP3 protein could have a role in energy expenditure, it may be suggested that hypolipidemic agents may have a beneficial role in the treatment of the cachectic syndrome.

Curcumin, a natural product present in turmeric, decreases tumor growth but does not behave as an anticachectic compound in a rat model

Systemic administration of curcumin [1,7-bis(4-hydroxy-3-methoxyphenil)1,6-heptadiene-3,5-dione] (20 microg/kg body weight) for 6 consecutive days to rats bearing the highly cachectic Yoshida AH-130 ascites hepatoma resulted in an important inhibition of tumor growth (31% of total cell number). Interestingly, curcumin was also able to reduce (24%) in vitro tumor cell content at concentrations as low as 0.5 microM without promoting any apoptotic events. Although systemic administration of curcumin has previously been shown to facilitate muscle regeneration, administration of the compound to tumor-bearing rats did not result in any changes in muscle wasting, when compared with the non-treated tumor-bearing animals. Indeed, both the weight and protein content of the gastrocnemius muscle significantly decreased as a result of tumor growth and curcumin was unable to reverse this tendency. It is concluded that curcumin, in spite of having clear antitumoral effects, has little potential as an anticachectic drug in the tumor model used in the present study.

Hepatic transport of gluconeogenic substrates during tumor growth in the rat

Hepatic gluconeogenic substrates (alanine, lactate, and glycerol) transport have been studied in liver plasma membrane vesicles from rats bearing the ascitic tumor Yoshida AH-130 hepatoma. Hepatic alanine uptake was increased in membrane vesicles from tumor-bearing animals as compared with those isolated from non-tumor-bearing controls. Although no changes were observed in relation with KM (2.19 and 2.10 mM for control and tumor groups, respectively), the presence of the tumor caused a clear increase in Vmax (3.07 and 5.04 nmol alanine/mg protein, respectively). The time course of lactate uptake showed no differences between the tumor-bearing animals and their corresponding controls. Both time course and kinetic experiments showed that liver glycerol uptake was due to passive diffusion and therefore cannot contribute to explain the enhanced utilization of this hepatic gluconeogenic substrate during tumor growth. The results suggest that hepatic alanine uptake may be an important factor accounting for its increased utilization for glucose synthesis in tumor-bearing rats.

Interleukin-15 mediates reciprocal regulation of adipose and muscle mass: a potential role in body weight control

Interleukin (IL)-15 is a cytokine which is highly expressed in skeletal muscle. Cell culture studies have indicated that IL-15 may have an important role in muscle fiber growth and anabolism. However, data concerning the metabolic effects of this cytokine in vivo are lacking. In the present study, IL-15 was administered to adult rats for 7 days. While IL-15 did not cause changes in either muscle mass or muscle protein content, it induced significant changes in the fractional rates of both muscle protein synthesis and degradation, with no net changes in protein accumulation. Additionally, IL-15 administration resulted in a 33% decrease in white adipose tissue mass and a 20% decrease in circulating triacylglycerols; this was associated with a 47% lower hepatic lipogenic rate and a 36% lower plasma VLDL triacylglycerol content. The decrease in white fat induced by IL-15 was in adipose tissue. No changes were observed in the rate of lipolysis as a result of cytokine administration. These findings indicate that IL-15 has significant effects on both protein and lipid metabolism, and suggest that this cytokine may participate in reciprocal regulation of muscle and adipose tissue mass.

The divergent effects of tumour necrosis factor-alpha on skeletal muscle: implications in wasting

Tumour necrosis factor-alpha (TNF) is a pleiotropic cytokine that can have effects on many cell types, including skeletal muscle, the most abundant tissue (representing almost 45% of body weight), where many effects of this cytokine have been described. Thus, TNF receptors have been described in muscle tissue, and different investigations have revealed effects of the cytokine on membrane potential, glucose uptake and metabolism, amino acid transport and protein turnover. However, the results found are relatively divergent, therefore the main aim of the present review has been to clarify and reconcile some of the most contradictory studies concerning the effects of TNF on metabolism in skeletal muscle.

Short-term effects of leptin on skeletal muscle protein metabolism in the rat

We have examined the short-term effects of leptin on protein metabolism in the rat. Indeed, an intravenous leptin administration (100 microg/kg body weight), which resulted in no changes in circulating insulin in the time interval studied, induced a decrease in the incorporation of (14)C-leucine to (14)C-skeletal muscle protein. No changes were observed in relation to muscle protein degradation (either measured in vivo following isotope preloading or in vitro as tyrosine released into the incubation medium) and gene expression associated with the different proteolytic systems (cathepsin B, m-calpain and ubiquitin-proteasome system). The effects of leptin on amino acid incorporation into muscle protein do not seem to be direct because incubation of isolated EDL muscles in the presence of 10 microg/ml of leptin did not modify either the protein incorporation or the oxidation of (14)C-leucine. It may, therefore, be suggested that leptin is able to influence protein synthesis in skeletal muscle through the action of an unknown mediator.

Lack of effect of the cytokine suppressive agent FR167653 on tumour growth and cachexia in rats bearing the Yoshida AH-130 ascites hepatoma

Daily s.c. administration of 6 mg/kg of FR167653 (an inhibitor of the synthesis of interleukin-1 and tumour necrosis factor-alpha) to rats bearing the ascites hepatoma Yoshida AH-130 (a highly cachectic tumour) did not prevent either the anorexia or the massive weight loss - affecting both adipose tissue and skeletal muscle - present in the cachectic animals. The compound did not affect the circulating levels of triacylglycerols or other metabolites such as glucose or lactate. Nor did the administration of FR167653 influence tumour growth. It is concluded that the drug is unable to reverse the cachectic state in this particular experimental tumour model.

Interleukin-15 antagonizes muscle protein waste in tumour-bearing rats

Tissue protein hypercatabolism (TPH) is an important feature in cancer cachexia, particularly with regard to the skeletal muscle. The Yoshida AH-130 rat ascites hepatoma is a model system for studying the mechanisms involved in the processes that lead to tissue depletion, since it induces in the host a rapid and progressive muscle wasting, primarily due to TPH. The present study was aimed at investigating if IL-15, which is known to favour muscle fibre hypertrophy, could antagonize the enhanced muscle protein breakdown in this cancer cachexia model. Indeed, IL-15 treatment partly inhibited skeletal muscle wasting in AH-130-bearing rats by decreasing (8-fold) protein degradative rates (as measured by 14C-bicarbonate pre-loading of muscle proteins) to values even lower than those observed in non-tumour-bearing animals. These alterations in protein breakdown rates were associated with an inhibition of the ATP-ubiquitin-dependent proteolytic pathway (35% and 41% for 2.4 and 1.2 kb ubiquitin mRNA, and 57% for the C8 proteasome subunit, respectively). The cytokine did not modify the plasma levels of corticosterone and insulin in the tumour hosts. The present data give new insights into the mechanisms by which IL-15 exerts its preventive effect on muscle protein wasting and seem to warrant the implementation of experimental protocols involving the use of the cytokine in the treatment of pathological states characterized by TPH, particularly in skeletal muscle, such as in the present model of cancer cachexia.

Calpain-3 gene expression is decreased during experimental cancer cachexia

The Yoshida AH-130 rat ascites hepatoma is a model system for studying the mechanisms involved in the protein hypercatabolism associated with cancer cachexia. The present study was aimed at investigating if the calpain-3 gene expression in skeletal muscle was affected by tumor growth. The results presented clearly show that calpain-3 gene expression is considerably reduced in experimental cancer cachexia, while there is a reciprocal change in the expression of the ubiquitin-dependent proteolytic system and in the ubiquitous m-calpain. The results, observed during cancer cachexia, suggest a potential counterregulatory role of calpain-3 in muscle proteolysis.

DNA fragmentation occurs in skeletal muscle during tumor growth: A link with cancer cachexia?

In two different experimental models of cancer cachexia, the rat Yoshida AH-130 ascites hepatoma and the mouse Lewis lung carcinoma, the implantation of the tumor caused a loss of body weight which was associated with a reduction in the weight of different skeletal muscles, as well as with their protein content. The decrease in protein content was accompanied by a reduction in DNA content. Interestingly, the protein/DNA ratio was unchanged in the skeletal muscle of the tumor-bearing animals as compared with the non-tumor-bearing controls. Analysis of DNA fragmentation in skeletal muscle clearly showed enhanced laddering in the skeletal muscle of tumor-bearing animals, suggesting an apoptotic phenomenon. Interestingly, the degree of laddering (total DNA fragmented) increased with tumor burden. These results suggest that DNA fragmentation may be a primary event in cancer-associated cachexia.

Does the mechanism responsible for TNF-mediated insulin resistance involve the proteasome?

Recent studies have demonstrated that in many pathological states there is an overproduction of tumour necrosis factor-alpha (TNF). Interestingly, TNF also seems to be responsible for the insulin resistance associated with these pathological states, since decreases the tyrosine kinase activity of the insulin receptor. Our group has demonstrated that TNF is able to activate the proteasome-mediated ubiquitin-dependent proteolysis. Since this proteolytic system is involved in the control of receptor-associated tyrosine kinase activity (i.e. insulin receptor), it is postulated here that the mechanism of TNF-induced insulin resistance is mediated by the activation of the proteasomic, ubiquitin-dependent proteolysis.

Leptin and tumor growth in rats

We have examined the role of leptin in tumor-induced anorexia in 2 different tumor models. In rats bearing the Yoshida AH-130 ascites hepatoma, the reduction in food intake becomes important from day 6 after tumor inoculation. Interestingly, at day 4, when the animals do not show any anorectic behavior, circulating leptin levels were already reduced. Indeed, in all the tumor-bearing groups studied the levels of leptin were lower than in control animals. Moreover, the changes in the circulating levels paralleled changes in adipose tissue leptin mRNA expression, even at early stages following tumor inoculation when neither food intake nor fat stores were modified by the presence of a tumor. Interestingly, 7-day pair-fed controls showed changes similar to those present in tumor-bearing rats. These results agree with previous observations relating fasting to decreased leptin expression. Similar results were observed in another tumor model, the mouse Lewis lung carcinoma; i.e., at day 8 after tumor inoculation (when the animals did not show anorexia) both the circulating levels and the adipose leptin mRNA expression were also reduced. Our results suggest that experimental cancer-induced anorexia is not related to leptin changes.

Leptin administration to lactating rats is unable to induce changes in lipid metabolism in white adipose tissue or mammary gland

During lactation in the rat, despite hyperphagia, there are no changes in either the plasma levels or the gene expression of leptin. Removal of the litter, however, results in an important increase in the circulating concentration of leptin. Administration of leptin to lactating rats resulted in no changes in the in vivo lipogenic rate and lipoprotein lipase (LPL) activity in either adipose tissue or mammary gland, although there was an increase in insulin levels as a consequence of leptin administration. Conversely, litter removal resulted in an important decrease of LPL activity and lipogenic rate in the mammary gland while an increase in these parameters took place in adipose tissue. It is concluded that leptin is not the signal responsible for the changes in lipid metabolism that take place both in adipose tissue and mammary gland following litter removal.

Tumour growth and nitrogen metabolism in the host (Review)

Tumour growth is frequently associated with massive loss of body weight and negative nitrogen balance leading to cachexia, one of the worst features of malignancy accounting for nearly two thirds of cancer deaths. At the metabolic level, cachexia is associated with depletion of body lipid stores as well as loss of skeletal muscle protein, which is manifested as an excessive nitrogen loss. The present study reviews the modulations of nitrogen metabolism in tumour-bearing conditions. In addition, the role of different mediators (such as cytokines) in the development of protein wasting is discussed. Particular emphasis has been given to tumour necrosis factor-alpha (TNF-alpha) which seems to have a key role in mediating changes related to nitrogen metabolism in the tumour-bearing host.

Resveratrol, a natural product present in wine, decreases tumour growth in a rat tumour model

Resveratrol administration to rats inoculated with a fast growing tumour (the Yoshida AH-130 ascites hepatoma) caused a very significant decrease (25%) in the tumour cell content. The effects of this diphenol were associated with an increase in the number of cells in the G2/M cell cycle phase. Interestingly, flow cytometric analysis of the tumour cell population revealed the existence of an aneuploid peak (representing 28% of total), which suggests that resveratrol causes apoptosis in the tumour cell population resulting in a decreased cell number.

Different cytokines modulate ubiquitin gene expression in rat skeletal muscle

Intravenous administration of different cytokines caused important changes in the expression of ubiquitin genes in skeletal muscle. Tumour necrosis factor-alpha caused a 2.2- and 1.9-fold increase in the expression of the 2.4 and 1.2 kb transcripts, respectively. Administration of interferon-gamma also caused a 2.2- and 1.8-fold increase in the 2.4 and 1.2 kb transcripts, respectively. While administration of leukaemia inhibitory factor and interleukin-6 resulted in no changes in ubiquitin gene expression, interleukin-1 administration also caused an increase in both ubiquitin gene transcripts (2.8- and 1.9-fold for the 2.4 and 1.2 kb transcripts, respectively). The results suggest that some of the cytokine effects on the ubiquitin system gene expression could be related to the enhanced skeletal muscle proteolysis found during cancer cachexia and other pathological states.

Leptin levels and gene expression during the perinatal phase in the rat

The role of leptin in controlling food intake and adiposity has been the aim of many different investigations in the last 3 years. Pregnancy and lactation are two physiological situations associated with a clear hyperphagia (together with important changes in metabolism and adipose mass) to sustain the different and varying demands for foetal growth and milk production respectively. We therefore focused on the role of leptin in perinatal hyperphagia. The circulating leptin levels and leptin gene expression in adipose tissue of both pregnant and lactating rats were examined. Pregnant rats showed unchanged adipose tissue leptin mRNA levels but increased circulating leptin; this probably reflects the high fat carcass content characteristic of pregnancy. Conversely, lactating rats did not show any change either in circulating leptin or adipose tissue mRNA levels. Litter-removal caused a significant increase in both circulating leptin levels and gene expression. The results obtained permit us to suggest that leptin does not seem to have a role in controlling food intake during the perinatal phase.

Role of TNF receptor 1 in protein turnover during cancer cachexia using gene knockout mice

The implantation of the Lewis lung carcinoma (a fast-growing mouse tumour that induces cachexia) to both wild-type and gene-deficient mice for the TNF-alpha receptor type I protein (Tnfr1 degree/Tnfr1 degree), resulted in a considerable loss of carcass weight in both groups. However, while in the wild-type mice there was a loss of both fat and muscle, in the gene-knockout mice muscle wastage was not affected to the same extent. In both groups, tumour burden resulted in significant increases in circulating TNF-alpha, a cytokine which, as we have previously demonstrated, can induce protein breakdown in skeletal muscle. Muscle wastage in wild-type mice was accompanied by an increase in the fractional rate of protein degradation, while no changes were observed in protein synthesis. The result is a decreased rate of protein accumulation that accounts for the muscle weight loss observed as a result of tumour burden. In contrast, gene knockout mice did not have significantly lower rates of protein accumulation as a result of tumour implantation. The increase in protein degradation in the tumour-bearing wild mice was accompanied by an enhanced expression of both ubiquitin and proteasome subunit genes, all of them related to the activation of the ATP-dependent proteolytic system in skeletal muscle. Tumour-bearing gene-deficient mice did not show any increase in gene expression. It is concluded that TNF-alpha (alone or in combination with other cytokines) is responsible for the activation of protein breakdown in skeletal muscle of tumour-bearing mice.

Short-term effects of leptin on lipid metabolism in the rat

In this study, we have examined the short-term effects of leptin on lipid metabolism in the rat. Acute leptin administration induced hypertriglyceridaemia (31% increase in plasma triacylglycerols) which was not associated with changes in lipoprotein lipase activity in white adipose tissue. Surprisingly, leptin administration did not induce any changes in the lipogenic rate in either white adipose tissue or liver. Leptin administration caused a decreased tissue uptake of exogenous 14C-triacylglycerols. These data suggest that leptin induces important changes in lipid uptake in adipose tissue and skeletal muscle which could be responsible for the observed hypertriglyceridaemia.

Tumour necrosis factor-alpha does not cross the rat placenta

In the last few years there has been a considerable proliferation of studies suggesting that tumour necrosis factor-alpha (TNF) has a very important physiological role in pregnancy. Its presence in the fetus has been related to several important roles such as cell growth and differentiation or immune protection. The aim of the present work was to analyze whether maternal TNF could reach the fetal circulation. The results found after in vivo [125I]TNF administration to pregnant rats at term demonstrate that, TNF does not cross the placenta and therefore it may be suggested that the cytokine which is found in the fetus is synthesized in its organs.

Prevention of cancer and cardiovascular diseases: a common strategy?

Cancer and cardiovascular diseases are two pathological states involving uncontrolled proliferation of either tumor or vascular smooth muscle cells. Interestingly, both types of disease can be prevented by the same type of chemical agent, such as marine polyunsaturated fatty acids, sulfur-containing compounds present in garlic, and wine polyphenols, among others, which seem to be fairly effective in the prevention of certain types of cancer and cardiovascular diseases. This is supported by numerous epidemiological studies and laboratory experiments involving animal models. It is therefore suggested that the mode of action of these compounds interfering with the development of these pathological states share some common trends. This could be taken into consideration in future studies related to the molecular mechanisms leading to these diseases as well as with the chemopreventive potential of some dietary components.

Was tumour necrosis factor-alpha responsible for the fetal malformations associated with thalidomide in the early 1960s?

Prescription of thalidomide as a sedative to pregnant women in the early 1960s resulted in a dramatic number of fetal malformations that affected over ten thousand babies. Although tumour necrosis factor-alpha (TNF-alpha) is basically a cytotoxic molecule produced by macrophages when activated by invasive stimuli (such as bacterial endotoxin or tumour growth), it could have an important role in pregnancy, especially in early embryonic development. On these lines, both in human subjects and experimental animals, the cytokine is expressed and synthesized in endometrium, placenta and fetus. Evidence is presented here suggesting that the embryonic action of thalidomide was mediated by TNF-alpha, since the drug is a powerful inhibitor of the synthesis of this cytokine.

Tumor growth influences skeletal muscle protein turnover in the pregnant rat

The implantation of a fast growing tumor (the Yoshida AH-130 ascites hepatoma) to mid-pregnant rats resulted in no changes in fetus weight, in spite of an important body weight decrease observed in the mother. Tumor-bearing pregnant rats showed an accelerated muscle protein degradation that resulted in decreases in both gastrocnemius and soleus muscle weight and protein content. Although very slight changes were observed in liver protein turnover after tumor implantation, muscle protein degradation and ubiquitin gene expression were increased (in relation with the non-tumor-bearing pregnant rats) in the first postimplantation period (0-4 d), whereas it remained lower in the second studied period (4-7 d), compensating for the initial differences when the whole period (0-7 d) was considered. Similar results were observed when muscle protein synthesis was studied. On the whole, tumor growth resulted in a slightly decreased protein accumulation rate. The results presented suggest that the implantation of this tumor in the pregnant rat has little or no consequences in fetal growth but results in an important muscle waste in the mother.

Lipid metabolism in tumour-bearing mice: studies with knockout mice for tumour necrosis factor receptor 1 protein

The implantation of the Lewis lung carcinoma (a fast-growing mouse tumour that induces cachexia) to both wild-type and gene-deficient mice for the tumour necrosis factor (TNF) receptor type I protein (Tnfr1(0)/Tnfr1(0)), resulted in a considerable loss of carcass (26%) and white (77%) and brown adipose (37%) tissue weights in the wild-type mice, while it induced much less marked effects in the gene-deficient mice. Tumour burden also inflicted an important decrease in total lipoprotein lipase (LPL) activity in epididymal white adipose tissue (50%) in the wild-type mice while no changes were observed in the knockout mice. In addition, all tumour-bearing animals were clearly hypertriglyceridaemic (80% increase in circulating triacylglycerols in wild-type and 36% in knockout mice). It is concluded that although TNF seems to be to some extent responsible for adipose waste, LPL changes and hyperlipaemia (via receptor I), the role of other cytokines (alone or in combination with TNF) in promoting changes in lipid metabolism during cancer cachexia cannot be discarded.

TNF and pregnancy: the paradigm of a complex interaction

Although tumour necrosis factor-alpha (TNF) was originally described as a cytotoxic molecule produced by macrophages when activated by certain stimuli (such as bacterial endotoxin or tumour cells), a large body of evidence suggests that TNF plays a role in pregnancy. Both in humans and experimental animals, TNF is expressed and synthesized in the endometrium, placenta and fetus. Here we review evidence in support of positive roles for the cytokine in gestation (such as early pregnancy maintenance, and the contribution of TNF to the maintenance of a complex cytokine-hormone network or to parturition). We also present evidence supporting the idea that TNF acts as a negative regulator of pregnancy, or does not play any significant role in gestation at all.

The increased skeletal muscle protein turnover of the streptozotocin diabetic rat is associated with high concentrations of branched-chain amino acids

Experimental streptozotocin-induced diabetes resulted in important changes in body weight which were associated with abnormalities in water and food intake. In addition, diabetic rats showed a clear muscle atrophy involving a decrease in both skeletal muscle size and protein content. This was accompanied by a marked loss of total carcass nitrogen. These changes were related to important alterations in protein turnover in skeletal muscle. Thus, the diabetic animals showed changes in the fractional protein rates of both synthesis (decreased by 37%) and degradation (increased by 140%). The increased protein degradation observed in the muscle of the diabetic animals was associated with important changes in the concentration of both circulating and muscle amino acids. Interestingly, the diabetic animals did not show important changes in either liver or kidney protein turnover rates, in spite of having a clear increase (over 50%) in kidney mass. In addition, and although the total amino acid concentration was not affected by the diabetic state, the chemically induced diabetic animals showed important elevations of branched-chain amino acids (leucine, isoleucine, and valine) in both blood and skeletal muscle. Similarly, important decreases in the blood concentrations of glutamate+glutamine, alanine, glycine, proline, serine, and threonine were also observed. These observations reinforce the idea of the association between muscle protein wasting, increased protein turnover, and alterations in branched-chain amino acids previously proposed by our group.

Comparative effects of beta2-adrenergic agonists on muscle waste associated with tumour growth

The implantation of the Yoshida AH-130 ascites hepatoma (a fast growing tumour) to rats resulted in a dramatic loss of both white adipose tissue and muscle (skeletal and cardiac) mass. Administration of beta2-adrenergic agonists to tumour-bearing rats resulted in a partial recovery of skeletal muscle and heart mass. Treatment of the tumour-bearing animals with the different drugs (salbutamol, salmeterol and clenbuterol) did not influence tumour growth or food intake so it can be suggested that the effects were solely due to metabolic changes. In addition, while the three drugs had clear effects on gastrocnemius muscles, clenbuterol and salbutamol had also an effect on soleus, and salbutamol had a clear effect on cardiac muscle. It is suggested that any of the studied beta2-adrenergic agonists (but perhaps, particularly salmeterol) could be used clinically in the treatment of cancer cachexia.

Neutral amino acid transport in placental plasma membrane vesicles in the late pregnant rat. Evidence for a B0-like transport system

Rat placental plasma membrane vesicles have been used to study both alanine and leucine transport at late gestation. The results presented are consistent with the presence of more than two separate transport systems for neutral amino acids in the rat placenta. One system is clearly Na(+)-independent and transports alanine (KM approximately or = 2 mM; Vmax approximately or = 360 pmol ala/mg prot x 5 s), leucine (KM approximately or = 0.07 mM; Vmax approximately or = 100 pmol leu/mg prot x 5 s), serine, cysteine and 2-amino-2 norbornane carboxylic acid (BCH) showing similar properties to the L system, present in many cell types. The other systems are Na(+)-dependent and transport alanine (a, KM approximately or = 5 mM; Vmax approximately or = 3761 pmol ala/mg prot x 5 s; b, KM approximately or = 0.07 mM; Vmax approximately or = 376 pmol ala/mg prot x 5 s), cysteine, serine and leucine (KM approximately or = 0.2 mM; Vmax approximately or = 112 pmol leu/mg prot x 5 s) with different kinetic behaviour referring affinity and capacity. While one of them is sensitive to inhibition by methylaminoisobutyric acid (MeAIB), the other is a B0-like system similar to that characterized in bovine brush-border enterocyte membrane vesicles.

alpha-Adrenergic receptors may contribute to the hypertriglyceridemia associated with tumour growth

The inoculation of the Yoshida AH-130 ascites hepatoma to rats resulted in an important loss of adipose tissue associated with a decrease in lipoprotein lipase (LPL) activity. Tumour burden also resulted in an important hyperlipidemia which affected both triglyceride and free fatty acids. Administration of phentolamine (an alpha-adrenergic antagonist) to tumour-bearing rats did not influence LPL activity, but it reversed the increase in plasma triglycerides associated with tumour burden. It is suggested that the hypertriglyceridemia associated with tumour growth may be, in part, a consequence of the effect of catecholamines on hepatic triglyceride secretion, via alpha-adrenergic receptors.

Tumour growth and fetal uptake of amino acids in the pregnant rat

The aim of the present investigation was to determine the effects of maternal tumour burden on fetal growth and to relate them to amino acid availability to the fetus. A fast-growing tumour, the Yoshida AH-130 ascites hepatoma, was inoculated into rats during pregnancy. Late pregnant rats bearing a rapidly-growing tumour presented a normal conceptus mass while the tumour cell content was unaffected by gestation. In addition, no changes were found in fetal uptake of amino acids as measured by the fetal accumulation of [14C]aminoisobutyrate and [14C] cycloleucine. However, increased alanine and leucine concentrations in the fetal circulation of the tumour-bearing rats suggest an enhanced fetal amino acid availability which does not seem to be the result of changes in placental or fetal relative blood flow, as indicated by the tissue accumulation of [14C]DDT, which were actually lower in the tumour-bearing rats. It may be suggested that tumour burden induces changes in placental amino acid transport systems.

Anti-TNF treatment reverts increased muscle ubiquitin gene expression in tumour-bearing rats

Implantation of the ascitic tumour Yoshida AH-130 hepatoma (a cachectic tumour) resulted in important increases in muscle ubiquitin gene expression. Administration of daily injections of 25 mg/kg b.w. polyclonal goat anti-murine TNF IgG preparation to tumour-bearing rats abolished the increase in muscle ubiquitin gene expression observed in the control (non-anti-TNF-treated) tumour-bearing rats. It is concluded that TNF can have an important role in the activation of the ubiquitin-dependent proteolytic system during tumour growth.

Muscle hypercatabolism during cancer cachexia is not reversed by the glucocorticoid receptor antagonist RU38486

In rats into which a fast growing ascites hepatoma (Yoshida AH-130) had been transplanted, tumor growth elicited a marked loss of body weight and tissue waste, particularly of the skeletal muscle. This depletion has been associated with enhanced rates of protein breakdown, mainly due to hyperactivation of the ATP-ubiquitin-dependent proteolytic system [Llovera, M., García-Martínez, C., Agell, N., Marzábal, M., López-Soriano, F.J. and Argilés, J.M. (1994) FEBS Lett., 338, 311-318]. Profound alterations of the hormonal status and the production of tumor necrosis factor have been involved in the development of such wasting syndrome [Tessitore, L., Costelli, P. and Baccino, F.M. (1993) Br. J. Cancer, 67, 15-23]. In the present study, the role of glucocorticoids in muscle hypercatabolism was investigated using the glucocorticoid receptor antagonist RU38486. The treatment with this drug was unable to interfere with the development of cachexia in the AH-130 hosts with regard to tissue weight as well as to muscle protein turnover rates. As one would expect, the RU38486 was also ineffective in lowering both the expression of ubiquitin mRNA and the degree of muscle protein ubiquitinization in AH-130 bearers. These data allow us to exclude that glucocorticoids play a direct crucial role in the development of cachexia in this tumor model.

Tumour growth results in changes in placental amino acid transport in the rat: a tumour necrosis factor alpha-mediated effect

The implantation of a fast growing tumour (Yoshida AH-130 ascites hepatoma) to late pregnant rats resulted in no changes in fetal growth, this possibly being associated with an important increase in the fetal uptake of maternal-derived amino acids [Carbó, López-Soriano and Argilés (1995) Endocrinology 136, 3579-3584]. The present investigation was undertaken to see whether the presence of the tumour induced changes in placental transport systems. For alanine transport, although no changes in affinity (Km) were observed, tumour growth resulted in a 192% increase in Vmax in the Na(+)-independent component. Kinetic analysis of the Na(+)-dependent component resulted in two clearly different components: while the low-affinity and high-capacity component was unaffected by tumour growth, the high-affinity, low-capacity component of the tumour-bearing rats showed an important increase in Vmax. (78%). With regard to leucine transport, tumour burden induced important increases in the Na(+)-independent component, not only in Km (262%) but also in Vmax. (189%). Since elevated tumour necrosis factor-alpha (TNF) concentrations have been reported in this kind of tumour model, we performed the same type of transport experiments in rats chronically treated with TNF, the results obtained showing great similarities with those observed with tumour growth. The Vmax. of Na(+)-independent alanine transport was also increased by the cytokine (104%) while no changes were observed in affinity. TNF treatment also induced an increase in the Vmax. (67%) of the Na(+)-dependent (high-affinity, low-capacity) component while no changes in affinity were observed. Concerning leucine kinetics, TNF treatment, as in the case of tumour growth, also increased Km (155%) and Vmax. (72%) associated with Na(+)-independent transport. Interestingly, treatment with the cytokine increased both the Km (43%) and Vmax. (64%) of the Na(+)-dependent component. The inhibition patterns suggest the existence of more that one Na(+)-dependent transport for alanine although the majority of the amino acid is transported through the A system. The results presented suggest that, during gestation, the mother is able to adapt her placental amino acid transport systems to compensate for the nitrogen drainage associated with tumour growth and thus provide the fetus with enough amino acids to allow its normal growth, and that TNF could be responsible for the triggering of this compensatory mechanism.

Lack of effect of eicosapentaenoic acid in preventing cancer cachexia and inhibiting tumor growth

It has been recently reported that a diet enriched in n-3 polyunsaturated fatty acids reduces the growth of different kinds of tumors as well as the host tissue hypercatabolic state frequently associated. The rat ascites hepatoma Yoshida AH-130 is a fast growing tumor that causes a rapid and progressive body weight loss in the host and tissue waste associated with a hypercatabolic condition. Plasma levels of classical hormones and humoral mediators (prostaglandin E2 and tumor necrosis factor-alpha) are early perturbed after tumor transplantation (Tessitore, L., Costelli, P. and Baccino, F.M. (1993) Humoral mediation for cachexia in tumour-bearing rats. Br. J. Cancer, 67, 16-23). Enhanced protein degradation rates and alteration of lipoprotein lipase activity mainly account for the wasting of protein and adipose mass, respectively. However, the daily intragastric administration of eicosapentaenoic acid (1.5 g/kg body wt) to AH-130 bearing rats was completely ineffective either in preventing tissue waste or in reducing tumor growth. The low degree of differentiation and the high growth rate of the AH0130 hepatoma probably account for this lack of effect.

Interleukin-1 receptor antagonist (IL-1ra) is unable to reverse cachexia in rats bearing an ascites hepatoma (Yoshida AH-130)

The mechanisms leading to the development of cancer cachexia are still poorly understood. Recently, cytokines such as interleukin 1 and tumour necrosis factor-alpha have been involved as mediators of the tissue wasting consequent to tumour growth. The rat ascites hepatoma Yoshida AH-130 is a highly anaplastic tumour that causes in the host an early and marked depletion of both the skeletal muscle and the adipose tissue, mainly accounted for by a hypercatabolic state. Profound hormonal alterations and the release of tumour necrosis factor-alpha and interleukin 1 by the tumour cells likely concur in forcing the metabolic balance towards the catabolic side [1]. In order to possibly achieve the correction of this wasting condition, the AH-130 bearing rats were administered a daily s.c. dose of interleukin 1 receptor antagonist (IL-1ra; 2 mg/kg). This factor, however, was completely ineffective in either inhibiting tumour proliferation or in preventing the consequent tissue depletion and protein hypercatabolism. These observations suggest that interleukin 1 is not important, at least in this model system, for either the development of cachexia or tumour growth.