[Chronic allograft dysfunction: role of immunosuppressive treatment]

Renal transplantation is the treatment of choice for patients with end-stage renal disease. In recent years a major improvement has been observed in short-term graft survival, but there has been no corresponding improvement in long-term survival. Chronic allograft dysfunction (CAD) is an anatomical and clinical alteration that can lead to the loss of the transplanted organ without any specific cause. The pathogenesis of CAD, which still remains to be fully clarified, involves both immunological factors (acute rejection, subclincial rejection, HLA mismatches between donor and recipient, noncompliance, etc) and non-immunological factors (marginal donor ischemia/reperfusion injury, infection, cardiovascular risk factors, nephrotoxicity, etc). Immunosuppressive therapy represents one of the strategies for the prevention of CAD. The introduction into clinical practice of novel immunosuppressive agents with no or lower nephrotoxicity, like mycophenolate mofetile, rapamycin and everolimus, will make therapeutic strategies aimed at decreasing the incidence of CAD feasible.

Inflammatory cytokines increase mitochondrial damage in motoneuronal cells expressing mutant SOD1

Recent studies indicate that molecular signals from microglia determine disease progression in transgenic mice overexpressing mutant superoxide dismutase (mutSOD1) typical of amyotrophic lateral sclerosis patients and that toxicity of mutSOD1 in motor neurons descends from its tendency to associate with mitochondria. To assess whether the neurotoxicity of mutSOD1 is influenced by signals from glia, we challenged motoneuronal cells overexpressing either wild-type or mutant SOD1 with inflammatory cytokines. We have obtained evidence that combined treatment with tumor necrosis factor alpha and interferon gamma increases the fraction of both wtSOD1 and mutSOD1 associated with mitochondria, but these inflammatory cytokines dramatically alter morphological features and functionality of mitochondria only in cells expressing mutSOD1. As an effect downstream the increase in mitochondria-associated mutSOD1, the ratio between reduced and oxidized glutathione further shifts toward the oxidized form in this compartment and a clear death phenotype is evoked upon treatment with inflammatory cytokines. These results suggest that signals coming from non-neuronal cells contribute to death of motor neurons induced by mutSOD1 through reinforcement of mitochondrial damage.

Amyotrophic lateral sclerosis: from current developments in the laboratory to clinical implications

Amyotrophic lateral sclerosis (ALS) is a late-onset progressive degeneration of motor neurons occurring both as a sporadic and a familial disease. The etiology of ALS remains unknown, but one fifth of instances are due to specific gene defects, the best characterized of which is point mutations in the gene coding for Cu/Zn superoxide dismutase (SOD1). Because sporadic and familial ALS affect the same neurons with similar pathology, it is hoped that understanding these gene defects will help in devising therapies effective in both forms. A wealth of evidence has been collected in rodents made transgenic for mutant SOD1, which represent the best available models for familial ALS. Mutant SOD1 likely induces selective vulnerability of motor neurons through a combination of several mechanisms, including protein misfolding, mitochondrial dysfunction, oxidative damage, cytoskeletal abnormalities and defective axonal transport, excitotoxicity, inadequate growth factor signaling, and inflammation. Damage within motor neurons is enhanced by noxious signals originating from nonneuronal neighboring cells, where mutant SOD1 induces an inflammatory response that accelerates disease progression. The clinical implication of these findings is that promising therapeutic approaches can be derived from multidrug treatments aimed at the simultaneous interception of damage in both motor neurons and nonmotor neuronal cells.

Cysteine 111 affects aggregation and cytotoxicity of mutant Cu,Zn-superoxide dismutase associated with familial amyotrophic lateral sclerosis

Converging evidence indicates that aberrant aggregation of mutant Cu,Zn-superoxide dismutase (mutSOD1) is strongly implicated in familial amyotrophic lateral sclerosis (FALS). MutSOD1 forms high molecular weight oligomers, which disappear under reducing conditions, both in neural tissues of FALS transgenic mice and in transfected cultured cells, indicating a role for aberrant intermolecular disulfide cross-linking in the oligomerization and aggregation process. To study the contribution of specific cysteines in the mechanism of aggregation, we mutated human SOD1 in each of its four cysteine residues and, using a cell transfection assay, analyzed the solubility and aggregation of those SOD1s. Our results suggest that the formation of mutSOD1 aggregates are the consequence of covalent disulfide cross-linking and non-covalent interactions. In particular, we found that the removal of Cys-111 strongly reduces the ability of a range of different FALS-associated mutSOD1s to form aggregates and impair cell viability in cultured NSC-34 cells. Moreover, the removal of Cys-111 impairs the ability of mutSOD1s to form disulfide cross-linking. Treatments that deplete the cellular pool of GSH exacerbate mutSOD1s insolubility, whereas an overload of intracellular GSH or overexpression of glutaredoxin-1, which specifically catalyzes the reduction of protein-SSG-mixed disulfides, significantly rescues mutSOD1s solubility. These data are consistent with the view that the redox environment influences the oligomerization/aggregation pathway of mutSOD1 and point to Cys-111 as a key mediator of this process.

The submental island flap in head and neck reconstruction

The authors describe their experience with the submental island flap for the primary correction of head and neck deformities following oncologic surgery, over the past 5 years. The use of this flap is reported in 12 patients, with a mean age of 67 years, requiring facial or intraoral reconstruction. A brief review of the key points and some refinements in the operative technique are discussed. The reconstruction of defects with a submental island flap was successful in every patient. Complications encountered were one case of temporary palsy of the marginal mandibular branch of the facial nerve and one case of orocutaneous fistula. All the donor site defects were closed primarily. The submental island flap is an excellent choice for the reconstruction of head and neck defects because of its reliability, versatility, colour and texture match, and relative ease of application.

Melatonin decreases the oxidative stress produced by 2,4-dichlorophenoxyacetic acid in rat cerebellar granule cells

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most widely used herbicides due to its relatively moderate toxicity and to its biodegradability in the soil. In toxic concentrations, 2,4-D displays strong neurotoxicity, partly due to generation of free radicals. Since melatonin has remarkable antioxidant properties, the objective of this study was to assess to what extent it was effective in preventing the 2,4-D effect on redox balance of rat cerebellar granule cells (CGC) in vitro. Cellular viability, generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS), reduced glutathione (GSH) levels, and the activities of the antioxidant enzymes Cu/Zn-superoxide dismutase (Cu/Zn-SOD), Mn-SOD, selenium-glutathione peroxidase (Se-GPx) and catalase (CAT) were measured in CGC exposed to 2,4-D and/or melatonin for 48 h. In CGC cultures exposed to 2,4-D, cell viability, GSH levels and CAT activity decreased significantly whereas ROS generation and Se-GPx activities were augmented. Except for Se-GPx activity, all these changes were counteracted by the concomitant addition of 0.1 or 0.5 mM melatonin. In addition, incubation of CGC with melatonin alone resulted in augmentation of cell viability, GSH levels and Se-GPx activity. RNS generation and SOD activity remained unaffected by either treatment. Since melatonin was able to counteract most of redox changes produced by 2,4-D in CGC in culture, the experimental evidence reported further support the efficacy of melatonin to act as a neuroprotector.

Familial ALS-superoxide dismutases associate with mitochondria and shift their redox potentials

Recent studies suggest that the toxicity of familial amyotrophic lateral sclerosis mutant Cu, Zn superoxide dismutase (SOD1) arises from its selective recruitment to mitochondria. Here we demonstrate that each of 12 different familial ALS-mutant SOD1s with widely differing biophysical properties are associated with mitochondria of motoneuronal cells to a much greater extent than wild-type SOD1, and that this effect may depend on the oxidation of Cys residues. We demonstrate further that mutant SOD1 proteins associated with the mitochondria tend to form cross-linked oligomers and that their presence causes a shift in the redox state of these organelles and results in impairment of respiratory complexes. The observation that such a diverse set of mutant SOD1 proteins behave so similarly in mitochondria of motoneuronal cells and so differently from wild-type SOD1 suggests that this behavior may explain the toxicity of ALS-mutant SOD1 proteins, which causes motor neurons to die.

Antibodies to filamentous actin (F-actin) in type 1 autoimmune hepatitis

AIMS

To evaluate the diagnostic significance of anti-filamentous actin antibodies (A-FAA) assessed with a commercial ELISA in comparison with immunofluorescence reactivity and patterns of anti-smooth muscle antibodies (SMA); and to correlate A-FAA positivity with clinical, immunogenetic, laboratory, and histological features in patients with autoimmune hepatitis type 1 (AIH-1).

METHODS

We studied 78 consecutive untreated AIH-1 patients and 160 controls: 22 with autoimmune hepatitis type 2 (AIH-2), 51 with hepatitis C, 17 with coeliac disease (CD), 20 with primary biliary cirrhosis (PBC) and 50 blood donors. SMA was evaluated by indirect immunofluorescence (IIF) on frozen sections of rat tissues, and A-FAA with a modified commercial ELISA.

RESULTS

SMA was detected by IIF in 61 (78%) of 78 AIH-1 patients, of whom 47 (60%) had the SMA-T/G and 14 (18%) the SMA-V pattern. Of the pathological controls, 32 (20%) had the SMA-V pattern (25 with hepatitis C, 2 with AIH-2, 2 with PBC, 3 with CD). A-FAA were present in 55 AIH-1 patients (70.5%; 46 with SMA-T/G, 7 with SMA-V, and 2 SMA-negative), and in 10 controls (6%), of whom five had hepatitis C, two AIH-2, two PBC and one CD. The association between A-FAA and the SMA-T/G pattern was statistically significant (p<0.0001). A-FAA levels were higher in SMA-T/G positive than SMA-V positive AIH-1 patients and controls (p<0.0001). A-FAA positivity was significantly associated with higher gamma-globulin and IgG levels, but did not correlate with other considered parameters.

CONCLUSION

The modified A-FAA ELISA strictly correlates with the SMA-T/G pattern and is a reliable and operator independent assay for AIH-1. Detection of A-FAA, even if devoid of prognostic relevance, may be useful when interpretative doubts of standard IIF arise.

Superoxide dismutase 1 modulates expression of transferrin receptor

Copper-zinc superoxide dismutase (SOD1) plays a protective role against the toxicity of superoxide, and studies in Saccharomyces cerevisiae and in Drosophila have suggested an additional role for SOD1 in iron metabolism. We have studied the effect of the modulation of SOD1 levels on iron metabolism in a cultured human glial cell line and in a mouse motoneuronal cell line. We observed that levels of the transferrin receptor and the iron regulatory protein 1 were modulated in response to altered intracellular levels of superoxide dismutase activity, carried either by wild-type SOD1 or by an SOD-active amyotrophic lateral sclerosis (ALS) mutant enzyme, G93A-SOD1, but not by a superoxide dismutase inactive ALS mutant, H46R-SOD1. Ferritin expression was also increased by wild-type SOD1 overexpression, but not by mutant SOD1s. We propose that changes in superoxide levels due to alteration of SOD1 activity affect iron metabolism in glial and neuronal cells from higher eukaryotes and that this may be relevant to diseases of the nervous system.

Detection of 2,4-dichlorophenoxyacetic acid in rat milk of dams exposed during lactation and milk analysis of their major components

2,4-Dichlorophenoxyacetic acid (2,4-D) and its derivatives are herbicides widely used to control the growth of broadleaf and woody plant. Human and animal exposure to 2,4-D through agriculture use, food products, or use in lawn and garden care has been well documented, but little information is available on the transfer from serum to milk in exposed dams. In this study, we measured the content of 2,4-D in rat milk from mother exposed to 15, 25, 50 or 7 0mg 2,4-D/kg bw through the diet (4 treated groups, 8 dam each; 1 control group with 8 dams) over a period of 16 days starting on the post-natal day 1 (PND 1). The effect of 2,4-D on milk components was also evaluated. All doses tested caused a decrease in the body weight gain of the pups (4 groups, 64 pups each). It also produce a 30% in the content of total lipids and a changed the content of minor proteins in milk of the treated groups. 2,4-D produces an important decrease in some fatty acids content, being the polyunsaturated fatty acids the most affected. Further analysis showed that 2,4-D concentrations chromatographically detected both serum of dams and pups and milk were dose-dependent.

Apaf1 mediates apoptosis and mitochondrial damage induced by mutant human SOD1s typical of familial amyotrophic lateral sclerosis

Several studies have indicated that apoptotic pathways are responsible for the loss of motor neurons that constitute the hallmark of amyotrophic lateral sclerosis (ALS). In this study, we demonstrate that apoptosis induced by the expression of several mutant Cu,Zn superoxide dismutases (SOD1) typical of familial ALS is mediated by Apaf1, a scaffold protein involved in neural development. Using different cell lines of neuronal origin and modulating the expression of both mutant SOD1s and Apaf1, we show that the removal of Apaf1 prevents cells death. Interestingly, intercepting activation of the caspases cascade is also effective in preventing both the mitochondrial damage and the increase in the production of reactive oxygen species induced by fALS-SOD1, even in the presence of cytochrome c release. This death pathway may be crucial also for the pathogenesis of the sporadic form of the disease, where markers of increased oxidative stress and mitochondria damage have been found.

Characterization of a 2D ion chamber array for the verification of radiotherapy treatments

In this study we investigated the characteristics of a commercial ion chamber array and its performance in the verification of radiotherapy plans. The device was the 2D Array Seven29 model (PTW, Freiburg, Germany). This is a two-dimensional detector array with 729 ionization chambers uniformly arranged in a 27 x 27 matrix with an active area of 27 x 27 cm(2). The detector short-, medium- and long-term reproducibility have been tested through an extensive set of repeated measurements. Short-term reproducibility was well within 0.2%. Medium- and long-term reproducibility were within 1%, including set-up reproducibility errors and linac output fluctuations. Dose linearity was also assessed. The system response to dose was verified to be linear within the range 2-500 MU. Output factors matched very well pinpoint chamber measurements performed in the same experimental conditions with a maximum local percentage difference of 0.4%. Furthermore, the 2D Array sensitivity to millimetric collimator positional changes and to perturbation effect of irradiated area was tested. The comparison with ion chamber data carried out in water was very satisfying. Finally, measurements of wedge-modulated fields and IMRT beam sequence matched very well ion chamber dose profiles acquired in a water tank. The extensive tests performed in this investigation show that the 2D Array Seven29 is a reliable and accurate dosimeter and that it could be a useful tool for the quality assurance and the verification of radiotherapy plans.

Apoptosome inactivation rescues proneural and neural cells from neurodegeneration

Deficiency of the apoptosome component Apaf1 leads to accumulation of supernumerary brain cells in mouse embryos. We observed that neural precursor cells (NPCs) in Apaf1(-/-) embryos escape programmed cell death, proliferate and retain their potential to differentiate. To evaluate the circumstances of Apaf1(-/-) NPC survival and investigate their fate under neurodegenerative conditions, we established cell lines of embryonic origin (ETNA). We found that Apaf1(-/-) NPCs resist common apoptotic stimuli and neurodegenerative inducers such as amyloid-beta peptide (typical of Alzheimer's disease) and mutant G93A superoxide dismutase 1 (typical of familial amyotrophic lateral sclerosis). Similar results were obtained in Apaf1(-/-) primary cells. When death is prevented by Apaf1 deficiency, cytochrome c is released from mitochondria and rapidly degraded by the proteasome, but mitochondria remain intact. Under these conditions, neither activation by cleavage of initiator caspases nor release of alternative apoptotic inducers from mitochondria takes place. In addition, NPCs can still differentiate, as revealed by neurite outgrowth and expression of differentiation markers. Our findings imply that the mitochondrion/apoptosome pathway is the main route of proneural and neural cells to death and that its inhibition prevents them from dismantling in neurodegenerative conditions. Indeed, the ETNA cell model is ideally suited for exploring the potential of novel cell therapies for the treatment of human neurodegenerations.

Muscle function and functional ability improves more in community-dwelling older women with a mixed-strength training programme

BACKGROUND

Supervised training can reach a limited number of elderly people.

OBJECTIVE

To determine the impact of a 1-year mixed-strength training programme on muscle function (MF), functional ability (FA) and physical activity (PA).

SETTING

Twice-a-week hospital-based exercise classes and a once-a-week home session.

PARTICIPANTS

twenty-eight healthy community-dwelling men and women on the training programme and 20 controls aged over 75 years.

METHODS

Training with two multi-gym machines for the lower limbs at 60% of the repetition maximum (1RM). At-home subjects used elastic bands.

MEASUREMENTS

Maximum isometric strength of knee extensors (KE), ankle plantar flexors (PF), leg extensor power (LEP), functional reach (FR), chair rise 1 (CR1) and 10 times (CR10), bed rise (BR), six-minute walking test (6MWT), stair climbing (SC), get-up-and-go (GU&G), one-leg standing (1LS). PA was assessed with the Paqap questionnaire.

RESULTS

Women were significantly weaker than men at baseline: -47% for KE and -59% for PF. Training induced significant gains in MF and FA in the training females; males improved significantly only in FA. PA levels increased non-significantly (2%) in all of the training group.

CONCLUSIONS

Long-term mixed-strength programmes can improve MF and FA in elderly females, and FA in elderly males.