Pharmaceutical treatment of osteoarthritis

OBJECTIVE

To review the current state of pharmaceutical treatment recommendations for the management of osteoarthritis.

METHOD

A narrative review was drafted to describe treatment guidelines, mechanism of action, pharmacokinetics, and toxicity for nine classes of pharmaceuticals: 1) oral nonsteroidal anti-inflammatory drugs (NSAIDs), 2) topical NSAIDs, 3) COX-2 inhibitors, 4) duloxetine, 5) intra-articular corticosteroids, 6) intra-articular hyaluronic acid, 7) acetaminophen (paracetamol), 8) tramadol, and 9) capsaicin.

RESULTS

In general, oral and topical NSAIDs, including COX-2 inhibitors, are strongly recommended first-line treatments for osteoarthritis due to their ability to improve pain and function but are associated with increased risks in patients with certain comorbidities (e.g., heightened cardiovascular risks). Intra-articular corticosteroid injections are generally recommended for osteoarthritis management and have relatively minor adverse effects. Other treatments, such as capsaicin, tramadol, and acetaminophen, are more controversial, and many updated guidelines offer differing recommendations.

CONCLUSION

The pharmaceutical management of osteoarthritis is a constantly evolving field. Promising treatments are emerging, and medicines that were once considered conventional (e.g., acetaminophen) are gradually becoming less acceptable based on concerns with efficacy and safety. Clinicians need to consider the latest evidence and recommendations to make an informed decision with their patients about how to optimize treatment plans for patients with knee, hip, polyarticular, or hand osteoarthritis.

[Supporting the fragile equilibrium of the family relationship]

Constructing bonds within the family sphere helps to establish a stable relational equilibrium. When a member of the family suffers from psychological disorders, maintaining this bond is akin to walking a tightrope. It must therefore be reinforced by the professionalism of the caregiving teams, attentive to the patient and his or her family. The place and identification of peers and family and friends is, likewise, essential in order to be able to continue walking along this tightrope.

Outcomes of sympathectomy and vascular bypass for digital ischaemia in connective tissue disorders

All patients (36 hands) with connective tissue disorders who underwent periarterial sympathectomy of the hand alone or in conjunction with vascular bypass at our institution between 1995-2013 were reviewed. The durable resolution of ulcers was significantly higher in patients treated by periarterial sympathectomy and bypass than in patients treated by periarterial sympathectomy alone. Although there were more digital amputations in patients treated by periarterial sympathectomy alone, the difference was not statistically significant. Vascular bypass in conjunction with sympathectomy may be better than sympathectomy alone in patients with digital ischaemia related to connective tissue disorders.

LEVEL OF EVIDENCE

IV.

Intravenous Injection of Clinical Grade Human MSCs After Experimental Stroke: Functional Benefit and Microvascular Effect

Stroke is the leading cause of disability in adults. Many current clinical trials use intravenous (IV) administration of human bone marrow-derived mesenchymal stem cells (BM-MSCs). This autologous graft requires a delay for ex vivo expansion of cells. We followed microvascular effects and mechanisms of action involved after an IV injection of human BM-MSCs (hBM-MSCs) at a subacute phase of stroke. Rats underwent a transient middle cerebral artery occlusion (MCAo) or a surgery without occlusion (sham) at day 0 (D0). At D8, rats received an IV injection of 3 million hBM-MSCs or PBS-glutamine. In a longitudinal behavioral follow-up, we showed delayed somatosensory and cognitive benefits 4 to 7 weeks after hBM-MSC injection. In a separate longitudinal in vivo magnetic resonance imaging (MRI) study, we observed an enhanced vascular density in the ischemic area 2 and 3 weeks after hBM-MSC injection. Histology and quantitative polymerase chain reaction (qPCR) revealed an overexpression of angiogenic factors such as Ang1 and transforming growth factor-1 (TGF-1) at D16 in hBM-MSC-treated MCAo rats compared to PBS-treated MCAo rats. Altogether, delayed IV injection of hBM-MSCs provides functional benefits and increases cerebral angiogenesis in the stroke lesion via a release of endogenous angiogenic factors enhancing the stabilization of newborn vessels. Enhanced angiogenesis could therefore be a means of improving functional recovery after stroke.

Respective effects of oxygen and energy substrate deprivation on beta cell viability

Deficit in oxygen and energetic substrates delivery is a key factor in islet loss during islet transplantation. Permeability transition pore (PTP) is a mitochondrial channel involved in cell death. We have studied the respective effects of oxygen and energy substrate deprivation on beta cell viability as well as the involvement of oxidative stress and PTP opening. Energy substrate deprivation for 1h followed by incubation in normal conditions led to a cyclosporin A (CsA)-sensitive-PTP-opening in INS-1 cells and human islets. Such a procedure dramatically decreased INS-1 cells viability except when transient removal of energy substrates was performed in anoxia, in the presence of antioxidant N-acetylcysteine (NAC) or when CsA or metformin inhibited PTP opening. Superoxide production increased during removal of energy substrates and increased again when normal energy substrates were restored. NAC, anoxia or metformin prevented the two phases of oxidative stress while CsA prevented the second one only. Hypoxia or anoxia alone did not induce oxidative stress, PTP opening or cell death. In conclusion, energy substrate deprivation leads to an oxidative stress followed by PTP opening, triggering beta cell death. Pharmacological prevention of PTP opening during islet transplantation may be a suitable option to improve islet survival and graft success.

Microvascular plasticity after experimental stroke: a molecular and MRI study

BACKGROUND

Microvasculature plays a key role in stroke pathophysiology both during initial damage and extended neural repair. Moreover, angiogenesis processes seem to be a promising target for future neurorestorative therapies. However, dynamic changes of microvessels after stroke still remain unclear, and MRI follow-up could be interesting as an in vivo biomarker of these.

METHODS

The aim of this study is to characterize the microvascular plasticity 25 days after ischemic stroke using both in vivo microvascular 7T-MRI (vascular permeability, cerebral blood volume (CBV), vessel size index (VSI), vascular density) and quantification of angiogenic factor expressions by RT-qPCR in a transient middle cerebral artery occlusion rat model. CBV and VSI (perfused vessel caliber) imaging was performed using a steady-state approach with a multi gradient-echo spin-echo sequence before and 2 min after intravenous (IV) injection of ultrasmall superparamagnetic iron particles. Vascular density (per mm2) was derived from the ratio [ΔR₂/(ΔR₂*)²/³]. Blood brain barrier leakage was assessed using T₁W images before and after IV injection of Gd-DOTA. Additionally, microvessel immunohistology was done.

RESULTS

3 successive stages were observed: 1) 'Acute stage' from day 1 to day 3 post-stroke (D1-D3) characterized by high levels of angiopoietin-2 (Ang2), vascular endothelial growth factor receptor-2 (VEGFR-2) and endothelial NO synthase (eNOS) that may be associated with deleterious vascular permeability and vasodilation; 2) 'Transition stage' (D3-D7) that involves transforming the growth factors β1 (TGFβ1), Ang1, and tyrosine kinase with immunoglobulin-like and endothelial growth factor-like domains 1 (Tie1), stromal-derived factor-1 (SDF-1), chemokine receptor type 4 (CXCR-4); and 3) 'Subacute stage' (D7-D25) with high levels of Ang1, Ang2, VEGF, VEGFR-1 and TGFβ1 leading to favorable stabilization and maturation of microvessels. In vivo MRI appeared in line with the angiogenic factors changes with a delay of at least 1 day. All MRI parameters varied over time, revealing the different aspects of the post-stroke microvascular plasticity. At D25, despite a normal CBV, MRI revealed a limited microvessel density, which is insufficient to support a good neural repair.

CONCLUSIONS

Microvasculature MRI can provide imaging of different states of functional (perfused) microvessels after stroke. These results highlight that multiparametric MRI is useful to assess post-stroke angiogenesis, and could be used as a biomarker notably for neurorestorative therapy studies. Additionally, we identified that endogenous vessel maturation and stabilization occur during the 'subacute stage'. Thus, pro-angiogenic treatments, such as cell-based therapy, would be relevant during this subacute phase of stroke.

Studies of circulating microparticle release in peripheral blood after pancreatic islet transplantation

The loss of graft function after intraportal islet transplantation is likely multifactorial involving allogeneic rejection, recurrent autoimmunity, graft exhaustion due to a marginally implanted islet mass, immunosuppressant toxicity, and impaired β-cell regeneration. Because early markers of the loss of β-cell mass or function are lacking, monitoring of islet function remains a challenging issue. We have reported herein monitoring of membrane procoagulant microparticles (MPs) as markers of cell stress in the plasma of three recipients with various clinical histories. Early kinetics of C-peptide and MPs followed identical patterns during the first weeks after transplantation; a major increase probably reflected processes related to cell infusion and islet engraftment. Importantly in the case of rejection, MPs and C-peptide showed opposite patterns. A fall in C-peptide was associated with enhanced insulin needs. Our results suggested that a peak in MP levels might indicate rejection with prognotic value. Treatment of the loss of islet function by a new islet infusion or steroid therapy returned MP and C-peptide levels to their baselines with concomitant restoration of islet function. In the patient with suspected acute cellular rejection, MPs also appeared to be sensors of immunosuppressive steroid therapy.

The dual effect of mesenchymal stem cells on tumour growth and tumour angiogenesis

INTRODUCTION

Understanding the multiple biological functions played by human mesenchymal stem cells (hMSCs) as well as their development as therapeutics in regenerative medicine or in cancer treatment are major fields of research. Indeed, it has been established that hMSCs play a central role in the pathogenesis and progression of tumours, but their impact on tumour growth remains controversial.

METHODS

In this study, we investigated the influence of hMSCs on the growth of pre-established tumours. We engrafted nude mice with luciferase-positive mouse adenocarcinoma cells (TSA-Luc+) to obtain subcutaneous or lung tumours. When tumour presence was confirmed by non-invasive bioluminescence imaging, hMSCs were injected into the periphery of the SC tumours or delivered by systemic intravenous injection in mice bearing either SC tumours or lung metastasis.

RESULTS

Regardless of the tumour model and mode of hMSC injection, hMSC administration was always associated with decreased tumour growth due to an inhibition of tumour cell proliferation, likely resulting from deep modifications of the tumour angiogenesis. Indeed, we established that although hMSCs can induce the formation of new blood vessels in a non-tumoural cellulose sponge model in mice, they do not modify the overall amount of haemoglobin delivered into the SC tumours or lung metastasis. We observed that these tumour vessels were reduced in number but were longer.

CONCLUSIONS

Our results suggest that hMSCs injection decreased solid tumour growth in mice and modified tumour vasculature, which confirms hMSCs could be interesting to use for the treatment of pre-established tumours.

Intracerebral injection of human mesenchymal stem cells impacts cerebral microvasculature after experimental stroke: MRI study

Stroke, the leading cause of disability, lacks treatment beyond thrombolysis. The acute injection of human mesenchymal stem cells (hMSCs) provides a benefit which could be mediated by an enhancement of angiogenesis. A clinical autologous graft requires an hMSC culture delay incompatible with an acute administration. This study evaluates the cerebral microvascular changes after a delayed injection of hMSCs. At day 8 after middle cerebral artery occlusion (MCAo), two groups of rats received an intracerebral injection in the damaged brain of either 10 μL of cell suspension medium (MCAo-PBS, n = 4) or 4 × 10⁵ hMSCs (MCAo-hMSC, n = 5). Two control groups of healthy rats underwent the same injection procedures in the right hemisphere (control-PBS, n = 6; control-hMSC, n = 5). The effect of hMSCs on the microvasculature was assessed by MRI using three parameters: apparent diffusion coefficient (ADC), cerebral blood volume (CBV) and vessel size index (VSI). At day 9, eight additional rats were euthanised for a histological study of the microvascular parameters (CBV, VSI and vascular fraction). No ADC difference was observed between MCAo groups. One day after intracerebral injection, hMSCs abolished the CBV increase observed in the lesion (MCAo-hMSC: 1.7 ± 0.1% versus MCAo-PBS: 2.2 ± 0.2%) and delayed the VSI increase (vasodilation) secondary to cerebral ischaemia. Histological analysis at day 9 confirmed that hMSCs modified the microvascular parameters (CBV, VSI and vascular fraction) in the lesion. No ADC, CBV or VSI differences were observed between control groups. At the stroke post-acute phase, hMSC intracerebral injection rapidly and transiently modifies the cerebral microvasculature. This microvascular effect can be monitored in vivo by MRI.

Plasmacytoid dendritic cells induce efficient stimulation of antiviral immunity in the context of chronic hepatitis B virus infection

The immune control of hepatitis B virus (HBV) infection is essential for viral clearance. Therefore, restoring functional anti-HBV immunity is a promising immunotherapeutic approach to treatment of chronic infection. Plasmacytoid dendritic cells (pDCs) play a crucial role in triggering antiviral immunity through their ability to capture and process viral antigens and subsequently induce adaptive immune responses. We investigated the potential of pDCs to trigger antiviral cellular immunity against HBV. We used a human leukocyte antigen A (HLA-A)*0201(+) pDC line loaded with HLA-A*0201-restricted peptides derived from hepatitis B core/hepatitis B surface (HBc/HBs) antigens to amplify specific CD8 T cells ex vivo from chronic HBV patients and established a Hepato-HuPBL mouse model to address the therapeutic potential of the strategy in vivo. Stimulation of PBMCs or liver-infiltrating lymphocytes from HLA-A*0201(+) chronic HBV patients by HBc peptide-loaded pDCs elicited up to 23.1% and 76.1% HBV-specific CD8 T cells in 45.8% of cases. The specific T cells from the "responder" group secreted interferon-γ, expressed CD107 upon restimulation, and efficiently lysed HBV antigen-expressing hepatocytes. Circulating hepatitis B e antigen (HBeAg) was found to distinguish the group of patients not responding to the pDC stimulation. The therapeutic efficacy of the pDC vaccine was evaluated in immunodeficient NOD-SCID β(2) m(-/-) mice reconstituted with HBV patients' PBMCs and xenotransplanted with human HBV-transfected hepatocytes. Vaccination of Hepato-HuPBL mice with the HBc/HBs peptide-loaded pDCs elicited HBV-specific T cells able to specifically lyse the transfected hepatocytes and reduce the systemic viral load.

CONCLUSION

pDCs loaded with HBV-derived peptides can elicit functional virus-specific T cells. HBeAg appears to be critical in determining the outcome of immunotherapies in chronic HBV patients. A pDC-based immunotherapeutic approach could be of interest in attempts to restore functional antiviral immunity, which is critical for the control of the virus in chronic HBV patients.

[Femur reconstruction using combined autologous fibula transfer and humeral allograft]

Wide resection far into the femoral metaphysis may be required to treat malignant bone tumors in the pediatric and adolescent patient population. Biological reconstruction using a free, vascularized fibular graft is a well-established surgical technique. A short remaining femoral medullary canal and a relatively small fibula diameter can make fixation of the vascularized bone transfer difficult. Stable fixation and short fusion times, however, can be achieved with the use of an additional humeral allograft and plate osteosynthesis.

Magnetic resonance imaging and fluorescence labeling of clinical-grade mesenchymal stem cells without impacting their phenotype: study in a rat model of stroke

Human mesenchymal stem cells (hMSCs) have strong potential for cell therapy after stroke. Tracking stem cells in vivo following a graft can provide insight into many issues regarding optimal route and/or dosing. hMSCs were labeled for magnetic resonance imaging (MRI) and histology with micrometer-sized superparamagnetic iron oxides (M-SPIOs) that contained a fluorophore. We assessed whether M-SPIO labeling obtained without the use of a transfection agent induced any cell damage in clinical-grade hMSCs and whether it may be useful for in vivo MRI studies after stroke. M-SPIOs provided efficient intracellular hMSC labeling and did not modify cell viability, phenotype, or in vitro differentiation capacity. Following grafting in a rat model of stroke, labeled hMSCs could be detected using both in vivo MRI and fluorescent microscopy until 4 weeks following transplantation. However, whereas good label stability and unaffected hMSC viability were observed in vitro, grafted hMSCs may die and release iron particles in vivo.

Pyrosequencing, a method approved to detect the two major EGFR mutations for anti EGFR therapy in NSCLC

Background

Epidermal Growth Factor Receptor (EGFR) mutations, especially in-frame deletions in exon 19 (ΔLRE) and a point mutation in exon 21 (L858R) predict gefitinib sensitivity in patients with non-small cell lung cancer. Several methods are currently described for their detection but the gold standard for tissue samples remains direct DNA sequencing, which requires samples containing at least 50% of tumor cells.

Methods

We designed a pyrosequencing assay based on nested PCR for the characterization of theses mutations on formalin-fixed and paraffin-embedded tumor tissue.

Results

This method is highly specific and permits precise characterization of all the exon 19 deletions. Its sensitivity is higher than that of "BigDye terminator" sequencing and enabled detection of 3 additional mutations in the 58 NSCLC tested. The concordance between the two methods was very good (97.4%). In the prospective analysis of 213 samples, 7 (3.3%) samples were not analyzed and EGFR mutations were detected in 18 (8.7%) patients. However, we observed a deficit of mutation detection when the samples were very poor in tumor cells.

Conclusions

pyrosequencing is then a highly accurate method for detecting ΔLRE and L858R EGFR mutations in patients with NSCLC when the samples contain at least 20% of tumor cells.

Intracoronary autologous mononucleated bone marrow cell infusion for acute myocardial infarction: results of the randomized multicenter BONAMI trial

AIMS

Intracoronary administration of autologous bone marrow cells (BMCs) leads to a modest improvement in cardiac function, but the effect on myocardial viability is unknown. The aim of this randomized multicentre study was to evaluate the effect of BMC therapy on myocardial viability in patients with decreased left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI) and to identify predictive factors for improvement of myocardial viability.

METHODS AND RESULTS

One hundred and one patients with AMI and successful reperfusion, LVEF ≤45%, and decreased myocardial viability (resting Tl201-SPECT) were randomized to either a control group (n = 49) or a BMC group (n = 52). Primary endpoint was improvement of myocardial viability 3 months after AMI. Baseline mean LVEF measured by radionuclide angiography was 36.3 ± 6.9%. Bone marrow cell infusion was performed 9.3 ± 1.7 days after AMI. Myocardial viability improved in 16/47 (34%) patients in the BMC group compared with 7/43 (16%) in the control group (P = 0.06). The number of non-viable segments becoming viable was 0.8 ± 1.1 in the control group and 1.2 ± 1.5 in the BMC group (P = 0.13). Multivariate analysis including major post-AMI prognostic factors showed a significant improvement of myocardial viability in BMC vs. control group (P = 0.03). Moreover, a significant adverse role for active smoking (P = 0.04) and a positive trend for microvascular obstruction (P = 0.07) were observed.

CONCLUSION

Intracoronary autologous BMC administration to patients with decreased LVEF after AMI was associated with improvement of myocardial viability in multivariate-but not in univariate-analysis. A large multicentre international trial is warranted to further document the efficacy of cardiac cell therapy and better define a group of patients that will benefit from this therapy.

CLINICAL TRIAL REGISTRATION INFORMATION

URL: http://www.clinicaltrials.gov. Unique identifier NCT00200707.

A novel cancer vaccine strategy based on HLA-A*0201 matched allogeneic plasmacytoid dendritic cells

Background

The development of effective cancer vaccines still remains a challenge. Despite the crucial role of plasmacytoid dendritic cells (pDCs) in anti-tumor responses, their therapeutic potential has not yet been worked out. We explored the relevance of HLA-A*0201 matched allogeneic pDCs as vectors for immunotherapy.

Methods and Findings

Stimulation of PBMC from HLA-A*0201⁺ donors by HLA-A*0201 matched allogeneic pDCs pulsed with tumor-derived peptides triggered high levels of antigen-specific and functional cytotoxic T cell responses (up to 98% tetramer⁺ CD8 T cells). The pDC vaccine demonstrated strong anti-tumor therapeutic in vivo efficacy as shown by the inhibition of tumor growth in a humanized mouse model. It also elicited highly functional tumor-specific T cells ex-vivo from PBMC and TIL of stage I-IV melanoma patients. Responses against MelA, GP100, tyrosinase and MAGE-3 antigens reached tetramer levels up to 62%, 24%, 85% and 4.3% respectively. pDC vaccine-primed T cells specifically killed patients' own autologous melanoma tumor cells. This semi-allogeneic pDC vaccine was more effective than conventional myeloid DC-based vaccines. Furthermore, the pDC vaccine design endows it with a strong potential for clinical application in cancer treatment.

Conclusions

These findings highlight HLA-A*0201 matched allogeneic pDCs as potent inducers of tumor immunity and provide a promising immunotherapeutic strategy to fight cancer.

[Extracorporeal photochemotherapy or immunotherapy using cells modified by photochemistry]

Extracorporeal photochemotherapy (ECP) is an autologous cell therapy used for the treatment of diseases involving pathogenic cells: cutaneous T-cell lymphoma, organ rejection and graft versus host disease. During an ECP procedure, patients receive a cellular product consisting of autologous mononuclear cells, containing the pathogenic cells, treated with a photosensitising agent and an UV-A radiation. The aim of the treatment is to induce a specific immune reaction modulating the activity of untreated pathogenic lymphocytes responsible for the disease and therefore an improvement of clinical manifestations. The precise mechanisms of action remain to be defined in humans. Its efficacy coupled with the absence of side effects could lead to decrease the use of immunosuppressive drugs. PCE appears as an immunotherapy using cells modified by photochemistry, which allows specific immune modulation of pathogenic lymphocytes.

Splenic lymphoma in a short-beaked echidna (Tachyglossus aculeatus)

A 23-year-old, male short-beaked echidna (Tachyglossus aculeatus) housed at a North American zoo was successfully treated for flea-associated anaemia, but subsequently died. Cause of death was presumptive septicaemia secondary to splenic lymphoma. This is only the fifth case of neoplasia reported in this monotreme species, and the first from outside of Australia.

Intravenous administration of 99mTc-HMPAO-labeled human mesenchymal stem cells after stroke: in vivo imaging and biodistribution

Human mesenchymal stem cells (hMSC) are a promising source for cell therapy after stroke. To deliver these cells, an IV injection appears safer than a local graft. We aimed to assess the whole-body biodistribution of IV-injected (99m)Tc-HMPAO-labeled hMSC in normal rats (n = 9) and following a right middle cerebral artery occlusion (MCAo, n = 9). Whole-body nuclear imaging, isolated organ counting (at 2 and 20 h after injection) and histology were performed. A higher activity was observed in the right damaged hemisphere of the MCAo group [6.5 +/- 0.9 x 10(-3) % of injected dose (ID)/g] than in the control group (3.6 +/- 1.2 x 10(-3) %ID/g), 20 h after injection. In MCAo rats, right hemisphere activity was higher than that observed in the contralateral hemisphere at 2 h after injection (11.6 +/- 2.8 vs. 9.8 +/- 1.7 x 10(-3) %ID/g). Following an initial hMSC lung accumulation, there was a decrease in pulmonary activity from 2 to 20 h after injection in both groups. The spleen was the only organ in which activity increased between 2 and 20 h. The presence of hMSC was documented in the spleen, liver, lung, and brain following histology. IV-injected hMSC are transiently trapped in the lungs, can be sequestered in the spleen, and are predominantly eliminated by kidneys. After 20 h, more hMSC are found in the ischemic lesion than into the undamaged cerebral tissue. IV delivery of hMSC could be the initial route for a clinical trial of tolerance.

Pyrosequencing method to detect KRAS mutation in formalin-fixed and paraffin-embedded tumor tissues

KRAS mutation status has been reported to be a predictive marker of tumor response to epidermal growth factor receptor (EGFR) inhibitors. We have designed a pyrosequencing assay based on nested polymerase chain reaction (PCR) to characterize KRAS mutation status using formalin-fixed and paraffin-embedded tumor tissues. Mutant and wild-type KRAS cell lines were used to determine the specificity and sensitivity (detection limit approximately 5% mutant alleles) of the method. The results obtained for tumor samples were 95% comparable to those obtained by dideoxy sequencing. Analysis of KRAS mutation using nested PCR and pyrosequencing is a simple, robust, fast, and sensitive method that can be used with formalin-fixed and paraffin-embedded tissues.

Oct-4, Rex-1, and Gata-4 expression in human MSC increase the differentiation efficiency but not hTERT expression

Micro-environment seems to exert an important influence on human mesenchymal stem cell (MSC) differentiation and proliferative capacity in bone marrow as well as in culture ex vivo. Oct-4, Rex-1, and TERT genes are well-known for the maintenance of pluripotentiality differentiation and the proliferative capacity of embryonic stem cells. Some previous data report expression of these embryonic factors in selected clones from bone marrow adult stem cells. Our goal was to study expression of Oct-4, Rex-1, and TERT in primary cultured human MSC according to the serum concentration. In addition, we have studied the expression of Gata-4 since this factor plays a key role in organogenesis. We hypothesized that low serum concentration with appropriate growth factors may induce an undifferentiated status with a re-expression of embryonic factors and extend differentiation capacity. Thus, using a defined culture medium, we report on the increased expression of Oct-4, Rex-1, and Gata-4 in human MSC. We have correlated this expression to an increase in differentiation efficiency towards osteogenic and adipogenic phenotypes. Our data suggest that the culture medium used permits the emergence of adult stem cells with a high differentiation capacity and expression of embryonic factors. These cells may have important implications for cell therapy.

Antioxidant supplementation preserves antioxidant response in physical training and low antioxidant intake

The present controlled-training double-blind study (supplemented (S) group,n7; placebo (P) group,n10) was designed to investigate whether an antioxidant mixture (Se 150 μg, retinyl acetate mg, ascorbic acid 120 mg, α-tocopheryl succinate) would allow overloaded triathletes to avoid adaptation failure in the antioxidant system. Dietary intakes were recorded. The supplement of Se, and vitamins A and E provided 100 % of the French RDA. Four weeks of overloaded training (OT) followed 4 weeks of normal training (NT). After NT and OT, biological studies were conducted at rest and after a duathlon test (run 5 km, cycle 20 km, run 5 km). During the 4-week period of NT, blood levels of GSH levels increased in response to supplementation (P<0·05) and remained elevated during OT. Plasma glutathione peroxidase activity was significantly higher in the S group in all situations after NT and OT (P<0·01). The S group had increased erythrocyte Cu,Zn-superoxide dismutase activity in response to OT (P<0·05). Supplementation significantly reduced (P<0·05) the magnitude in duathlon-induced creatine kinase isoenzyme MB mass increase, which tended to be higher with OT (P=0·09). We conclude that the antioxidant mixture helped to preserve the antioxidant system during an OT-induced stress in subjects with initially low antioxidant intakes. Effects of supplementation during NT and/or OT are shown mostly by the alleviated muscle damage. The effects of the antioxidant mixture were observed for doses that can be provided by a diversified and well-balanced diet. The maintenance of normal nutritional status with regard to the antioxidant intake (Se, vitamins C and E) plays a key role in antioxidant adaptive effects during NT and OT.

MnTMPyP, a metalloporphyrin-based superoxide dismutase/catalase mimetic, protects INS-1 cells and human pancreatic islets from an in vitro oxidative challenge

AIMS

Pancreatic islets can be lost early following allotransplantation from oxidative stress. Antioxidant enzyme overexpression could confer a beneficial effect on islets exposed to reactive oxygen species (ROS) and nitrogen species. Here, we tested the effect of MnTMPyP, a superoxide dismutase/catalase mimetic.

METHODS

INS-1 insulin-secreting cells or human islets were cultured with MnTMPyP and exposed to a superoxide donor (the hypoxanthine/xanthine oxidase (HX/XO) system), a nitric oxide donor [3-morpholinosydnonimine (SIN-1)] or menadione. Viability of INS-1 cells was assessed by WST-1 colorimetric assay and FACS analysis (Live/Dead test). ROS production was determined using fluorescent probes. Islet viability was estimated by WST-1 assay and endocrine function by static incubation.

RESULTS

Following MnTMPyP treatment, ROS production in INS-1 cells was reduced by 4- to 20-fold upon HX/XO challenge and up to 2-fold upon SIN-1 stress. This phenomenon correlated with higher viability measured by WST-1 or Live/Dead test. MnTMPyP preserved islet viability upon exposure to SIN-1 or menadione but not upon an HX/XO challenge. Similarly, decrease in insulin secretion tended to be less pronounced in MnTMPyP-treated islets than in control islet when exposed to SIN-1, but no changes were noticed during an HX/XO stress.

CONCLUSIONS

MnTMPyP was able to improve the viability of INS-1 cells and human islets exposed to oxidative challenges in vitro. Protection of INS-1 cells could be as high as 90%. This agent is therefore potentially attractive in situations involving the overproduction of ROS, such as islet transplantation.

Plasma glutathione peroxidase activity as a potential indicator of hypoxic stress in breath-hold diving

INTRODUCTION

Diving mammals can cope with oxidants which are produced in excess during the reoxygenation of hypoxic tissues. This study addresses the question of whether antioxidants can adapt and whether it allows humans to tolerate the hypoxic stress induced by a single breath-holding in the course of a dynamic diving exercise and protect them from oxidative insult.

METHODS

There were 20 male subjects who performed submaximal apnea dynamic diving (ADD). Nine control subjects stayed out of the water and breathed normally. Venous blood samples were collected 1 h before and immediatly after ADD.

RESULTS

ADD induced a significant increase in plasma glutathione peroxidase (GPx-3) activity (from 397.5 +/- 44.4 to 410 +/- 43 U x L(-1)), blood reduced glutathione (GSH) (from 1060 +/- 302 to 1292 +/- 213 micromol x L(-1)), and in plasma creatine kinase activity (from 215 +/- 137 to 235 +/- 152 U x L(-1)). The activity of the erythrocyte superoxide dismutase and glutathione peroxidase, as well as the blood oxidized glutathione and the plasma thiobarbituric acid reactive substances concentrations, were maintained at their basal level. The level of training, characterized by the duration and distance of the dive, had no effect on the markers used.

CONCLUSION

GPx-3 and GSH could constitute the most readily mobilizable antioxidants that would then contribute to the buffering against a sudden increase in the generation of radical oxygen species. These biomarkers could be used as tools for establishing oxidative stress during hypoxia. The response of GPx-3 to hypoxia could be of physiological relevance.

Human bone marrow mesenchymal stem cells can express insulin and key transcription factors of the endocrine pancreas developmental pathway upon genetic and/or microenvironmental manipulation in vitro

Multipotential stem cells can be selected from the bone marrow by plastic adhesion, expanded, and cultured. They are able to differentiate not only into multiple cell types, including cartilage, bone, adipose and fibrous tissues, and myelosupportive stroma, but also into mesodermal (endothelium), neuroectodermal, or endodermal (hepatocytes) lineages. Our goal was to characterize the multipotential capacities of human mesenchymal stem cells (hMSCs) and to evaluate their ability to differentiate into insulin-secreting cells in vitro. hMSCs were obtained from healthy donors, selected by plastic adhesion, and phenotyped by fluorescence-activated cell sorter and reverse transcription-polymerase chain reaction analysis before and after infection with adenoviruses coding for mouse IPF1, HLXB9, and FOXA2 transcription factors involved early in the endocrine developmental pathway. We found that native hMSCs have a pluripotent phenotype (OCT4 expression and high telomere length) and constitutively express NKX6-1 at a low level but lack all other transcription factors implicated in beta-cell differentiation. In all hMSCs, we detected mRNA of cytokeratin 18 and 19, epithelial markers present in pancreatic ductal cells, whereas proconvertase 1/3 mRNA expression was detected only in some hMSCs. Ectopic expression of IPF1, HLXB9, and FOXA2 with or without islet coculture or islet-conditioned medium results in insulin gene expression. In conclusion, our results demonstrated that in vitro human bone marrow stem cells are able to differentiate into insulin-expressing cells by a mechanism involving several transcription factors of the beta-cell developmental pathway when cultured in an appropriate microenvironment.

Extracorporeal chemophototherapy for the treatment of graft-versus-host disease: hematologic consequences of short-term, intensive courses

BACKGROUND AND OBJECTIVES

Extracorporeal chemophototherapy (ECP) is considered an immunomodulatory agent useful in both acute and chronic graft-versus-host disease (GVHD). Little is known about the best treatment schedule, and there are no data concerning hematologic parameters and cellular compositions of products during the treatment.

DESIGN AND METHODS

This was a single-center study of 27 patients treated with ECP for corticoresistant GVHD. Treatment was given in a short-term series of six courses over 3 weeks, and in case of response, consolidation treatment was given until complete response or stabilization of lesions.

RESULTS

Nine out of 12 patients with acute GVHD responded to treatment. In patients with chronic GVHD, 13 out of 15 patients responded (11 complete and 2 partial responses). Responses were obtained essentially in skin or gut lesions; ECP was of particular effect in three cases of bronchiolitis obliterans associated with transplantation, with all three patients responding. Hematologic consequences were studied in patients with chronic GVHD: hemoglobin levels increased significantly after treatment and a reduction in red blood cell transfusion requirements was also observed.

INTERPRETATION AND CONCLUSIONS

ECP is effective in both chronic and acute GVHD, particularly in lung forms. ECP can reduce the duration of immunosuppressive therapy and improve erythroid recovery. ECP product quality, including standardization for the number of mononuclear cells for each patient, needs further investigation.

An interaction between CD16 and CR3 enhances iC3b binding to CR3 but is lost during differentiation of monocytes into dendritic cells

The receptor for the iC3b fragment of complement, CR3, is involved in monocytes/macrophages and neutrophils phagocytosis. CR3 is known to interact with the low affinity receptor for Ig (CD16) and previous studies have suggested that this cooperation modulates CR3 functions. Herein we have studied the effect of CD16 on the ability of human monocytes CR3 to bind to iC3b. We show that iC3b binding to CR3 is inhibited by several reagents that are known to dissociate the CD16/CR3 complex. In addition, treatment of monocytes with soluble CD16 inhibited iC3b binding to CR3. Together, these data indicate that iC3b binding to monocyte CR3 is up-regulated by an interaction between membrane CD16 and CR3. The implication of CD16 in CR3 binding to iC3b was also analyzed after monocyte differentiation into dendritic cells (DC). Differentiation of monocytes into DC abrogates the cooperation between CD16 and CR3, due to a loss of CD16/CR3 interaction. In accordance, this phenomenon is associated with a lack of iC3b binding to DC. As a consequence, deposition of iC3b on apoptotic cells does not modify their phagocytosis by DC. In conclusion, we demonstrate a cooperation between CD16 and CR3 that favors iC3b binding to CR3 but is lost on DC.

Precision and accuracy of joint space width measurements of the medial compartment of the knee using standardized MTP semi-flexed radiographs

OBJECTIVE

To quantify the precision and accuracy of measurements of joint space width (JSW) and joint space narrowing (JSN) from the medial tibiofemoral compartment of knee radiographs using a simple and easily adaptable protocol.

METHODS

Radiographs of a caliper (a surrogate for JSW) were obtained to determine the precision limits of the system under ideal conditions. Bilateral knee radiographs from 10 healthy volunteers were obtained at three different times using the metatarsophalangeal (MTP) semi-flexed view posterior-anterior position without fluoroscopy. A backlit digitizing tablet and three manual methods were used to measure JSW and analyses of precision were performed. The accuracy of measuring change in JSW (a measure of JSN) was estimated from radiographs of cadaver knees that were placed in a servo-hydraulic device that moved the femur relative to the tibia through known intervals.

RESULTS

Radiographic measurements of the caliper inter-blade distance were comparable to the resolution limits of the backlit digitizing tablet (0.025 mm). Repeated radiography of healthy subject knees produced JSW standard deviation (SD) measurements of 0.08 mm by the median SD method, and 0.11 mm by repeated measures analysis. The accuracy of JSN measurements in the cadaver knees as a mean difference from the known reference value was 0.09 mm.

CONCLUSION

The results indicate a high level of precision in measurements of JSW from MTP semi-flexed view knee radiographs of normal volunteers. Reproducibility was attained through careful subject positioning without fluoroscopy and the use of a backlit digitizing tablet. From the cadaver study we can predict that greater than 0.13 mm of measured JSN represents actual or true change in JSN. This radiographic technique can be used as a primary measure for early knee osteoarthritis (OA) when cartilage thickness is decreasing and limited bony remodeling has occurred.

Overloaded training increases exercise-induced oxidative stress and damage

We hypothesized that overloaded training (OT) in triathlon would induce oxidative stress and damage on muscle and DNA. Nine male triathletes and 6 male sedentary subjects participated in this study. Before and after a 4-week OT, triathletes exercised for a duathlon. Blood ratio of reduced vs. oxidized glutathione (GSH/GSSG), plasma thiobarbituric acid reactive substances (TBARS), leukocyte DNA damage, creatine kinase (CK), and CK-MB mass in plasma, erythrocyte superoxide dismutase (SOD) activity, erythrocyte and plasma glutathione peroxidase (GSH-Px) activities, and plasma total antioxidant status (TAS) were measured before and after OT in pre- and postexercise situations. Triathletes were overloaded in response to OT. In rest conditions, OT induced plasma GSH-Px activity increase and plasma TAS decrease (both p < 0.05). In exercise conditions, OT resulted in higher exercise-induced variations of blood GSH/GSSG ratio, TBARS level (both p < 0.05), and CK-MB mass (p < 0.01) in plasma; and decreased TAS response (p < 0.05). OT could compromise the antioxidant defense mechanism with respect to exercise-induced response. The resulting increased exercise-induced oxidative stress and further cellular susceptibility to damage needs more study.

[Extracorporeal photochemotherapy for treatment of clonal T cell proliferations]

Extracorporeal photochimiotherapy (ECP) is based on the exposure of peripheral blood mononuclear cells to the photosensitizing agent (psoralen or 8MOP) and UVA radiation. Mononuclear cells are harvested by cytapheresis and reinfused to the patient after irradiation. This cell therapy has been shown to be effective in the treatment of selected diseases mediated by clonal T cells proliferation such as Sezary T cells lymphoma, rejection after solid organ transplantation and graft-versus-host disease but results obtained in autoimmune diseases are less convincing. ECP is well tolerated with very few side effects and can be combined with immunosuppressive drugs. Two methods of ECP are currently used: in the first one, the whole procedure is performed with the same equipment whereas in the second one, the cytapheresis is performed on a conventional cell separator and treated with an independent UVA irradiation: Experimental data and clinical results suggest that PCE might induced an immune response against pathological T cells clones. However, technical differences in the methods of PCE and weak knowledge on its mechanism of action impair the standardization and evaluation of this cell therapy process as well as its clinical development.

Activation of p53 by the cytoprotective aminothiol WR1065: DNA-damage-independent pathway and redox-dependent modulation of p53 DNA-binding activity

WR1065 is an aminothiol with selective cytoprotective effects in normal compared to cancer cells, which is used to protect tissues against the damaging effect of radiation and chemotherapeutic drugs. WR1065 has been shown to induce wild-type p53 accumulation and activation in cultured cells, suggesting a role of p53 in cytoprotection. However, the molecular mechanisms by which WR1065 activates p53 remain unclear. Here, we demonstrated that p53 accumulation by WR1065 in MCF-7 cells did not result from the formation of DNA-damage as measured by DNA fragmentation and Comet assay, nor from oxidative stress as detected by measurement of glutathione levels, lipid peroxidation and reactive oxygen species production. p53 activation by WR1065 was not prevented by inhibition of PI-3 kinases, and was still detectable in MCF-7 cells stably transfected with the oncoprotein E6, which repressed p53 induction by DNA damage. These data provided evidence that WR1065 induces p53 by a pathway different than the one elicited by DNA-damage. Direct reduction by WR1065 of key cysteines in p53 may play an important role in this alternative pathway, as shown by the fact that WR1065 activated the redox-dependent, DNA-binding activity of p53 in vitro.

Antioxidant supplementation and tapering exercise improve exercise-induced antioxidant response

OBJECTIVE AND METHODS

The present controlled-training, double-blind study (supplemented, n = 7; placebo, n = 9) investigated whether taper training (TT) and antioxidant supplementation, i.e., 150 micro g of selenium, 2000 IU of retinol, 120 mg of ascorbic acid and 30 IU of alpha-tocopherol, modulates antioxidant potential, redox status and oxidative damage occurrence both at rest and in response to exercise. Two weeks of TT followed four weeks of overloaded training. Dietary intakes were recorded. Before and after TT, triathletes did a duathlon consisting of 5-km run, 20-km bike and 5-km run. Biological studies were conducted at rest and after exercise.

RESULTS

Whatever the nutritional status, TT induced a decrease in resting blood reduced glutathione (GSH) concentration (p < 0.001), erythrocyte superoxide dismutase (SOD) activity (p < 0.0001) and plasma total antioxidant status (TAS) (p < 0.05). Only in the supplemented group (Su) with TT, did plasma glutathione peroxidase (GSH-Px) activity decrease (p < 0.05) and CD4(+) cell concentration increase (p < 0.05). However, antioxidant supplementation increased plasma TAS increase in response to exercise and TT (p < 0.05). After exercise, TT also induced a lower decrease in blood reduced and oxidized (GSSG) glutathione (p < 0.01) in both groups, but TT had no effect on lipoperoxidation as estimated by plasma thiobarbituric reactive substances or on muscular damage occurrence estimated by plasma creatine kinase isoenzyme MB mass.

CONCLUSION

During TT, antioxidant supplementation at nutritional doses reinforces antioxidant status response to exercise, with an effect on exercise-induced oxidative stress, and no effect on oxidative damage.

Protection of insulin-secreting INS-1 cells against oxidative stress through adenoviral-mediated glutathione peroxidase overexpression

OBJECTIVES

A large fraction of an islet graft can be lost early following allotransplantation from various non specific mechanisms including oxidative stress. Overexpression of antioxidant enzymes could confer a beneficial effect on islets exposed to reactive oxygen and nitrogen species. We examined the viability of beta cells driven to overexpress glutathione peroxidase (GPx) and exposed to a superoxide donor (hypoxanthine/xanthine oxidase HX/XO) and a nitric oxide donor (3-morpholinosydnonimine SIN-1).

METHODS

Cultured INS-1 rat-derived insulin-secreting cells were transfected by an E1-deleted adenovirus carrying GPx cDNA (AdGPx). Additional experiments were performed with an adenovector carrying Cu/Zn superoxide dismutase cDNA (AdSOD). Cellular viability was tested by the WST-1 colorimetric assay and functionality by static incubation.

RESULTS

AdGPx increased GPx activity within 48 hours from 0 (untransfected cells) to 60 +/- 11 U/g (cells transfected at an MOI of 25: 1). GPx overexpression significantly reduced cytotoxicity induced by HX/XO from 10.81 +/- 1.41 to 5.42 +/- 2.62% at 10 mU/ml and from 61.19 +/- 4.17 to 52.9 +/- 4.39% at 20 mU/ml (p=0.0002, transfected cells vs control cells). Doses of SIN-1 from 600 to 1000 micromol/l resulted in cytotoxicity ranging from 17.66 +/- 3.48 to 45.97 +/- 6.48% in control cells and from 5.65 +/- 1.37 to 35.80 +/- 5.59% in AdGPx transfected cells (p=0.015). The combination of AdGPx and AdSOD did not exhibit any synergistic cytoprotective effect. Control cells exposed to a HX/XO stress exhibited a reduction in glucose-theophylline stimulated insulin secretion by half, while stressed GPx overexpressing-cells maintained the same insulin secretion level than non-stressed cells.

CONCLUSIONS

Adenoviral-induced overexpression of GPx enhances the resistance of a rat beta cell line to both reactive oxygen (ROS) and reactive nitrogen species (RNS) cytotoxicity. Transposition of these findings to human islet transplantation with a clinically-relevant procedure deserves further investigations.

Quality control for the validation of extracorporeal photopheresis process using the Vilbert-Lourmat UV-A irradiation's system

In agreement with good practices for therapeutic use of human cells, quality control has to be performed to valid the process of extracorporeal photopheresis (ECP) with the Vilbert-Lourmat system. Since no protocol exists, we evaluated a technique based on the measurement of the inhibition of mitogen (PHA, Con-A, OKT3)-induced proliferation, in 164 procedures from 16 patients. Whatever the pathology, we observed a high proliferation rate in most samples, and we obtained over 90% ECP-induced inhibition in as many as 94% of the cases. Since this approach proved to be relevant regarding our objective, a protocol for the ECP process validation is proposed.

Enzymatic antioxidant balance and cognitive decline in aging – the EVA study

We studied whether primary enzymatic antioxidant protection should influence cognitive decline (CD) in subjects aged 62-72 years volunteers in the Etude du Vieillissement Antériel (EVA) cohort. At baseline, we measured red blood cells activities of two enzymes: cytoplasmic form of superoxide dismutase (CuZn-SOD) and seleno dependent glutathione peroxidase (GSH-Px). During the 4 year-follow up (follow-up rate of 81%), a drop of at least 3 points in MMSE score was observed in 71 subjects (7.2%) defining individuals with CD+ among the 980 individuals. Initial GSH-Px activity appeared to be significantly lower in individual CD+ (41.2 +/- 10.3 U/g Hb vs. 44.4 +/- 9.4 in CD-, p = 0.008). Conversely, there was an increase of CuZn-SOD activity in CD+ subjects (1.13 +/- 0.10 U/mg Hb vs. 1.10 +/- 0.10, p = 0.05). Taking into account the ratio between these two levels suggest that the equilibrium between these two enzymes, an important determinant of oxidative stress level, is associated with CD. These results are independent of other potential risk factors for CD (education, Apolipoprotein E, hypertension) and suggest that this primary enzymatic system could be related to CD during aging.

Cytotoxicity in ciprofloxacin-treated human fibroblast cells and protection by vitamin E

Quinolones (Qs) were shown to have cytotoxic effects in various cell lines including human carcinoma cells; however, mechanism of these effects was not fully understood. To investigate the possibility of the involvement of an oxidative stress induction in this mechanism of action, we examined viability of human fibroblast cells exposed to a Q antibiotic, ciprofloxacin (CPFX), and measured lipid peroxidation and total glutathione (GSH) levels, and activities of catalase (Cat), superoxide dismutases (SODs), glutathione peroxidase (GPx). The effects of vitamin E pretreatment on those parameters were also examined. Our results showed that the effect of CPFX on the viability of the cells, as determined by neutral red uptake assay, was time dependent. Cytotoxicity was not observed in the concentration range of 0.0129-0.387 mM CPFX when the cells were incubated for 24 hours. However, significant level of cytotoxicity was observed at concentrations 0.129 and 0.194 mM, and >0.129 mM, following 48 and 72 hours of exposure, respectively. When the cells were exposed to 0.194 mM CPFX for 48 hours, the level of lipid peroxidation increased and the content of total GSH decreased significantly; activities of total SOD, Mn SOD and CuZn SOD did not change; the decrease observed in the activity of Cat was not significant; and the activity of GPx was highly variable. Vitamin E pretreatment of the cells provided significant protection against CPFX-induced cytotoxicity; lowered the level of lipid peroxidation significantly, but increased the total GSH content only moderately; no change was observed in the activities of Cat and total SOD, but a significant increase in Mn SOD and a significant decrease in CuZn SOD were noticed. These results suggested that CPFX-induced cytotoxicity on human fibroblast cell cultures is related to oxidative stress, and vitamin E pretreatment can afford a protection.

Effects of cadmium and zinc on solar-simulated light-irradiated cells: potential role of zinc-metallothionein in zinc-induced genoprotection

Zinc is an essential oligoelement for cell growth and cell survival and has been demonstrated to protect cells from oxidative stress induced by UVA or from genotoxic stress due to UVB. In a recent work we demonstrated that the antioxidant role of zinc could be related to its ability to induce metallothioneins (MTs). In this study we identified the mechanism of zinc protection against solar-simulated light (SSL) injury. Cultured human keratinocytes (HaCaT) were used to examine MTs expression and localization in response to solar-simulated radiation. We found translocation to the nucleus, with overexpression of MTs in irradiated cells, a novel observation. The genoprotective effect of zinc was dependent on time and protein synthesis. DNA damage was significantly decreased after 48 h of ZnCl(2) (100 microM) treatment and is inhibited by actinomycin D. ZnCl(2) treatment (100 microM) led to an intense induction, redistribution, and accumulation of MT in the nucleus of irradiated cells. MT expression correlated with the time period of ZnCl(2) treatment. CdCl(2), a potent MT inducer, did not show any genoprotection, although the MTs were expressed in the nucleus. Overall our findings demonstrate that MTs could be a good candidate for explaining the genoprotection mediated by zinc on irradiated cells.

Hyperthermia assists survival of astrocytes from oxidative-mediated necrotic cell death

In response to many stresses and pathologic states, including different models of nervous system injury, cells synthesize a variety of proteins, most notably the inducible 72 kDa heat shock protein 70 (Hsp70), which plays important roles in maintaining cellular integrity and viability. We report here that cultured astrocytes from rat diencephalon express high levels of Hsp70 upon exposure to elevated temperatures, and are less vulnerable to a subsequent oxidative stress. Complex oxidative stress was induced by exposure of astrocytes to an aqueous extract of tobacco smoke. This resulted in both glutathione and ATP depletion, along with cell death that proceeded through a necrotic pathway. Pretreatment of cultures with the glutathione replenishing agent, N-acetyl-L-cysteine, prevented glutathione and ATP loss as well as necrotic cell death. Thermal stress also protected astrocytes from necrotic cell death but without affecting glutathione or ATP levels. We propose that heat shock protects astrocytes from necrosis induced by oxidative stress, probably as a result of Hsp70 synthesis, through an antioxidant-ATP independent mechanism. As Hsp70 may transfer from glial to neuronal cells, its synthesis by astrocytes may represent an important survival mechanism by which astrocytes protect neurons against oxidative-mediated cell death.

Toxicity of cadmium in tobacco smoke: protection by antioxidants and chelating resins

The effects of cadmium, an environmental toxin present in tobacco smoke, were studied in vitro in human monocytes and compared to those of tobacco smoke. Overexpression of the 72kDa heat shock/stress protein Hsp70 and cell death occurred with a similar time-course and to a similar extent in human monocytes exposed to either cadmium or tobacco smoke. Cadmium and tobacco smoke-mediated toxicity were associated with a decrease in the cellular content of glutathione and ATP and the glutathione precursor N-acetyl-L-cysteine prevented both cadmium and tobacco smoke-mediated toxicity. Furthermore, tobacco smoke-mediated toxicity was prevented by pretreatment with the cadmium chelator resin Chelex-100, supporting the conclusion that cadmium plays a major role in tobacco smoke-mediated toxicity.

Increased lipid peroxidation in pregnant women after iron and vitamin C supplementation

Iron overload could promote the generation of free radicals and result in deleterious cellular damages. A physiological increase of oxidative stress has been observed in pregnancy. A routine iron supplement, especially a combined iron and vitamin C supplementation, without biological justifications (low hemoglobin [Hb] and iron stores) could therefore aggravate this oxidative risk. We investigated the effect of a daily combined iron supplementation (100 mg/d as fumarate) and vitamin C (500 mg/d as ascorbate) for the third trimester of pregnancy on lipid peroxidation (plasma TBARS), antioxidant micronutriments (Zn, Se, retinol, vitamin E, (beta-carotene) and antioxidant metalloenzymes (RBC Cu-Zn SOD and Se-GPX). The iron-supplemented group (n = 27) was compared to a control group (n = 27), age and number of pregnancies matched. At delivery, all the women exhibited normal Hb and ferritin values. In the supplemented group, plasma iron level was higher than in the control group (26.90 +/- 5.52 mmol/L) and TBARs plasma levels were significantly enhanced (p < 0.05) (3.62 +/- 0.36 vs 3.01 +/- 0.37 mmol/L). No significant changes were observed in plasma trace elements and red blood cell antioxidant metalloenzymes. Furthermore, the alpha-tocopherol plasma level was lowered in the iron-supplemented groups, suggesting an increased utilization of vitamin E. These data show that pharmalogical doses of iron, associated with high vitamin C intakes, can result in uncontrolled lipid peroxidation. This is predictive of adverse effects for the mother and the fetus. This study illustrates the potential harmful effects of iron supplementation when prescribed only on the assumption of anemia and not on the bases of biological criteria.

Induction of thioredoxin by ultraviolet-A radiation prevents oxidative-mediated cell death in human skin fibroblasts

The present study analyzes the expression of the thioredoxin/thioredoxin reductase (Trx/TR) system in UVA-irradiated human skin fibroblasts. Irradiation increases the intracellular level of Trx and a time-dependent increase of Trx mRNA is observed. Our data indicate that Trx translocates from the cytoplasm to the nucleus. In addition, UV exposure results in an increase in TR synthesis. In order to evaluate the function of Trx/TR system, we investigated the antioxidant role of Trx in transient transfected cells. The ROS accumulation in UVA irradiated cells was assessed using flow cytometry. A 3-fold decrease in ROS production was observed in transiently transfected fibroblasts. These results indicate that Trx acts as an antioxidant protein in UVA irradiated fibroblasts. As ROS are inducers of cell death, this raises the question as to whether Trx is able to protect cells from apoptosis and/or necrosis induced by UVA. Six hours after UVA-irradiation, 29.92% of cells were annexin-V positive. This population was significantly reduced in Trx-transfected cells (8.58%). Moreover, this work demonstrates that Trx prevents the loss of the membrane potential of the mitochondria, the depletion of cellular ATP content, and the loss of cell viability induced by irradiation.

Modulation of exogenous and endogenous levels of thioredoxin in human skin fibroblasts prevents DNA damaging effect of ultraviolet A radiation

Thioredoxin (Trx) plays important biological roles both intra- and extracellularly via thiol redox control. We have previously demonstrated that Trx exhibited protective effects against UVA cytotoxicity in human skin fibroblasts. As an extension of the latter investigation, the present work is aimed at assessing ability of Trx to maintain genomic integrity in human skin fibroblasts upon exposure to UVA radiation. Indeed, UVA (320--380 nm) is mutagenic and induces genomic damage to skin cells. The alkaline comet assay was used in association with DNA repair enzyme including formamido pyrimidine glycosylase (Fpg) and endonuclease III (endo III) to estimate the amount of modified bases together with the level of strand breaks and alkali-labile sites. The HPLC-EC assay was applied to assess 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) levels and to permit the calibration of comet assay as previously described. We reported that overexpression of human Trx (transient transfection) as well as exogenous human recombinant Trx added to the culture medium, decreased the level of DNA damage in UVA irradiated cells. Interestingly, transfection appeared to prevent UVA-induced 8-oxodGuo (3.06 au per Joules.cm(-2) compared to 4.94 au per Joules.cm(-2) for nontransfected cells). Moreover, Trx accumulates into nuclei in transfected cells. This finding supports the notion that Trx is important for the maintenance of the integrity of genetic information. This work demonstrated that under conditions of UVA oxidative stress, Trx prevented the UVA-induced DNA damage.

Blood micronutrients in Algeria, relationships with sex and age

Despite trace elements and vitamins are major public health problems in some African countries, there are few studies reporting micronutrient status in North Africa. Therefore, it could be interesting to evaluate plasma concentrations of vitamin A, E and beta-cartene, along with zinc, copper, selenium erythrocyte glutathione peroxidase and superoxide dismutase in Algeria. Volunteers were randomly recruited in Constantine, Batna and Mila. Vitamins, trace elements and enzymes were measured in the University Hospital of Grenoble. 455 persons were included in the study. Subjects were divided in 3 groups: group I: 15 girls and 12 boys who were 6 to 12.9 years old, group II: 190 women and 192 men 13 to 49.9 years old, group III: 24 women and 24 men 50 to 65 years old. Plasma concentrations of micronutrients and enzymes are close to those commonly observed in Europe, except for vitamin A concentrations. Indeed, retinol levels are 30-35% lower than those reported in European countries, moreover almost 8% of the population showed retinol concentrations less than 1.05 mumol/l. beta-Carotene levels were also lower than in the French average population. Ten per cent of the population had plasma zinc levels lower than 10.6 mumol/l. Vitamin E, copper and selenium status seems satisfactory in Algeria. Vitamin A is not a public health problem, however a significant percentage of residents exhibits impaired vitamin A levels and may benefit from retinol supplementation. Larger studies are needed, and particularly in children, to detect possible higher prevalence of vitamin A deficiency in poor socio-economical classes and in inner geographic areas.

Selenium status in an iodine deficient population of the West Ivory Coast

Selenium is an essential trace element which is part of the active site of seleno-dependent glutathione peroxidase and type 1 deiodinase. Therefore, it plays a key role in thyroid hormone metabolism. The present work was undertaken in order to evaluate selenium status in two Ivory Coast populations: the first with high (Glanlé) and the second with low (Abidjan) prevalence of iodine deficiency. Selenium, glutathione peroxidase, glutathione reductase, glutathione and diglutathione were determined in blood and/or urine. In plasma and erythrocytes, selenium and glutathione peroxidase were dramatically low in Glanlé. Compared to Abidjan, selenium, glutathione peroxidase, vitamin E and riboflavin status were decreased whereas diglutathione was increased in Glanlé. The results clearly demonstrate a selenium deficiency and suggest an oxidant stress in Glanlé. Causes and consequences of this selenium deficiency and oxidant stress remain to be determined.

Human Immunodeficiency Virus Type 1 Tat Protein Impairs Selenoglutathione Peroxidase Expression and Activity by a Mechanism Independent of Cellular Selenium Uptake: Consequences on Cellular Resistance to UV-A Radiation

The expression of the HIV-1 Tat protein in HeLa cells resulted in a 2.5-fold decrease in the activity of the antioxidant enzyme glutathione peroxidase (GPX). This decrease seemed not to be due to a disturbance in selenium (Se) uptake. Indeed, the intracellular level of Se was similar in parental and tat-transfected cells. A Se enrichment of the medium did not lead to an identical GPX activity in both cell lines, suggesting a disturbance in Se utilization. Total intracellular 75Se selenoproteins were analyzed. Several quantitative differences were observed between parental and tat-transfected cells. Mainly, cytoplasmic glutathione peroxidase and a 15-kDa selenoprotein were decreased in HeLa-tat cells, while phospholipid hydroperoxide glutathione peroxidase and low-molecular-mass selenocompounds were increased. Thioredoxin reductase activity and total levels of 75Se-labeled proteins were not different between the two cell types. The effect of Tat on GPX mRNA levels was also analyzed. Northern blots revealed a threefold decrease in the GPX/glyceraldehyde phosphate dehydrogenase mRNA ratio in HeLa-tat versus wild type cells. By deregulating the intracellular oxidant/antioxidant balance, the Tat protein amplified UV sensitivity. The LD50 for ultraviolet radiation A was 90 J/cm2 for HeLa cells and only 65 J/cm2 for HeLa-tat cells. The oxidative stress occurring in the Tat-expressing cells and demonstrated by the diminished ratio of reduced glutathione/oxidized glutathione was not correlated with the intracellular metal content. Cellular iron and copper levels were significantly decreased in HeLa-tat cells. All these disturbances, as well as the previously described decrease in Mn superoxide dismutase activity, are part of the viral strategy to modify the redox potential of cells and may have important consequences for patients.

[Transition metals and nitric oxide production in human endothelial cells]

The bioavailability of endothelial nitric oxide (NO) is regulated by transition metals but their mechanisms of action on NO synthesis and degradation are not clearly understood. Using differential pulse amperometry and NO microelectrodes, local NO concentration was measured at the surface of cultured human umbilical vein endothelial cells (HUVECs) stimulated by histamine or thrombin in the presence of transition metal chelators. The agonist-activated NO release required both extracellular Ca2+ and transition metals. In the presence of 1 mM external Ca2+, a low concentration of EGTA (5 microM) inhibited by 40% the NO release from stimulated HUVECs. In the presence of extracellular L-arginine, the inhibitory effect of EGTA was even more marked and, in its absence, it was suppressed by adding exogenous superoxide dismutase. The decrease in NO release induced by the copper chelators, cuprizone and DETC, suggests that extracellular traces of Cu2+ could regulate NO availability.

Seasonal variations of antioxidant imbalance in Cuban healthy men

OBJECTIVE

To determine the antioxidant imbalance in healthy Cuban men 2y after the end of the epidemic neuropathy (50 862 cases from 1991 to 1993) and to evaluate its change over 1 y.

DESIGN

Prospective study.

SETTING

La Lisa health centres (Havana, Cuba).

SUBJECTS

One-hundred and ninety-nine healthy middle-aged men were selected and 106 completed the study. Subjects were studied at 3 month intervals over 1 year.

INTERVENTIONS

No invervention.

MAIN OUTCOME MEASURES

An assessment of dietary intake and the determination of blood lipid peroxides (TBARS), glutathione, diglutathione, glutathione peroxidase, superoxide dismutase, vitamin E, carotenoids, copper, zinc and selenium were performed at each period.

RESULTS

While dietary zinc, vitamins C and E, carotenoids and fat dietary intakes and blood concentrations were low for adult men compared to international reference ranges, serum TBARS concentrations were high at every period. Some significant seasonal variations were observed. The lowest carotenoids (P < 0.002) and vitamin C(P = 0.0001) intakes, serum beta-carotene (P = 0.0001) and lutein/zeaxanthin (P < 0.05) concentrations, and the highest blood TBARS (P = 0.0001) and diglutathione (P < 0.001) concentrations were observed at the end of the rainy season (October). This period seemed to pose the greatest risk of antioxidant imbalance.

CONCLUSIONS

Cuban men still represent a vulnerable population in terms of antioxidant imbalance. A national program of vegetable growing and increase in fruit and vegetable consumption is now evaluated in Cuba.

Metalloregulation of the tumor suppressor protein p53: zinc mediates the renaturation of p53 after exposure to metal chelators in vitro and in intact cells

The tumor suppressor p53 is a transcription factor which binds DNA through a structurally complex domain stabilized by a zinc atom. Zinc chelation disrupts the architecture of this domain, inducing the protein to adopt an immunological phenotype identical to that of many mutant forms of p53. In this report, we used 65Zn to show that incorporation of zinc within the protein was required for folding in the 'wild-type' conformation capable of specific DNA-binding. Using a cellular assay, we show that addition of extracellular zinc at concentrations within the physiological range (5 microM) was required for renaturation and reactivation of wild-type p53. Among other divalent metals tested (Cd2+, Cu2+, Co2+, Fe2+ and Ni2+), only Co2+ at 125 microM had a similar effect. Recombinant metallothionein (MT), a metal chelator protein, was found to modulate p53 conformation in vitro. In cultured cells, overexpression of MT by transfection could modulate p53 transcriptional activity. Taken together, these results suggest that zinc binding plays a regulatory role in the control of p53 folding and DNA-binding activity.

Effect of okadaic acid, a protein phosphatase inhibitor, on heat stress-induced HSP72 synthesis and thermotolerance

Heat stress proteins (HSPs), in particular HSP72, seem to play a major role in cell protection against lethal stresses such as hyperthermia or ischemia. HSP synthesis is negatively regulated by protein phosphatases, which are implicated in dephosphorylation processes. In the present study, we have investigated the effect of okadaic acid (OA, a protein phosphatase inhibitor) on heat stress-induced HSP72 synthesis and thermotolerance in smooth muscle cells (SMC). SMC were heat stressed (42 degrees C for 20 minutes) in the presence of 250 nM OA (HS+OA cells) or its vehicle (HS+V cells). Control (OA or V) cells were not heat stressed. HSP72 mRNA expression was determined 1, 1.5, 3, and 6 hours after heat stress by RT-PCR, and HSP72 synthesis was determined 6, 12, 24, 48, and 72 hours after heat stress by Western blotting. SMC survival of lethal hyperthermia (47 degrees C for 90 minutes) was assessed 6, 24, and 48 hours after heat stress by a tetrazolium assay. The maximal expression of HSP72 mRNA was markedly prolonged in HS+OA cells (until 6 hours after heat stress) compared to HS+V cells (1 hour after heat stress). The kinetics of HSP72 synthesis and thermotolerance of SMC were not different between HS+OA and HS+V cells. Baseline HSP72 mRNA and protein expression were similar in control V and OA cells. In conclusion, okadaic acid treatment of SMC potentiated HSP72 mRNA expression without affecting heat stress-induced HSP72 synthesis and thermotolerance.

Contrasting effects of NO and peroxynitrites on HSP70 expression and apoptosis in human monocytes

The free radicals nitric oxide (.NO) and superoxide (O(2)(-).) react to form peroxynitrite (ONOO(-)), a highly toxic oxidant species. In this study we investigated the respective effects of NO and ONOO(-) in monocytes from healthy human donors. Purified monocytes were incubated for 6 or 16 h with a pure NO donor (S-nitroso-N-acetyl-DL-penicillamine, 0-2 mM), an.NO/ONOO(-) donor (3-morpholinosydnonimine chlorhydrate, 0-2 mM) with and without superoxide dismutase (200 IU/ml), or pure ONOO(-). We provide evidence that 3-morpholinosydnonimine chlorhydrate alone represents a strong stress to human monocytes leading to a dose-dependent increase in heat shock protein-70 (HSP70) expression, mitochondrial membrane depolarization, and cell death by apoptosis and necrosis. These phenomena were abolished by superoxide dismutase, suggesting that ONOO(-), but not.NO, was responsible for the observed effects. This observation was further strengthened by the absence of a stress response in cells exposed to S-nitroso-N-acetyl-DL-penicillamine. Conversely, exposure of cells to ONOO(-) alone also induced mitochondrial membrane depolarization and cell death by apoptosis and necrosis. Thus ONOO(-) formation may well explain the toxic effect generally attributed to.NO.