Improvement of Charcot-Marie-Tooth Phenotype with a Nanocomplex Treatment in Two Transgenic Models of CMT1A

Curcumin has been shown to exert beneficial effects in peripheral neuropathies. Despite its known biological activities, curcumin has unfavorable pharmacokinetics. Its instability has been linked to its failure in clinical trials of curcumin for the treatment of human pathologies. For this reason, we developed curcumin-loaded cyclodextrin/cellulose nanocrystals (NanoCur) to improve its pharmacokinetics. The present study aims to assess the potency of a low dose of NanoCur in 2 Charcot-Marie-Tooth disease type 1A (CMT1A) rodent models at different stages of the disease. The efficiency of NanoCur is also compared to that of Theracurmin (Thera), a commercially available curcumin formulation. The toxicity of a short-term and chronic exposure to the treatment is investigated both in vitro and in vivo, respectively. Furthermore, the entry route, the mechanism of action and the effect on the nerve phenotype are dissected in this study. Overall, the data support an improvement in sensorimotor functions, associated with amelioration in peripheral myelination in NanoCur-treated animals; an effect that was not evident in the Thera-treated group. That was combined with a high margin of safety both in vivo and in vitro. Furthermore, NanoCur appears to inhibit inflammatory pathways that normally include macrophage recruitment to the diseased nerve. This study shows that NanoCur shows therapeutic benefits with minimal systemic toxicity, suggesting that it is a potential therapeutic candidate for CMT1A and, possibly, for other neuropathies.

Charcot-Marie-Tooth-1A and sciatic nerve crush rat models: insights from proteomics

The sensorimotor and histological aspects of peripheral neuropathies were already studied by our team in two rat models: the sciatic nerve crush and the Charcot-Marie-Tooth-1A disease. In this study, we sought to highlight and compare the protein signature of these two pathological situations. Indeed, the identification of protein profiles in diseases can play an important role in the development of pharmacological targets. In fact, Charcot-Marie-Tooth-1A rats develop motor impairments that are more severe in the hind limbs. Therefore, for the first time, protein expression in sciatic nerve of Charcot-Marie-Tooth-1A rats was examined. First, distal sciatic nerves were collected from Charcot-Marie-Tooth-1A and uninjured wild-type rats aged 3 months. After protein extraction, sequential window acquisition of all theoretical fragment ion spectra liquid chromatography and mass spectrometry was employed. 445 proteins mapped to Swiss-Prot or trEMBL Uniprot databases were identified and quantified. Of these, 153 proteins showed statistically significant differences between Charcot-Marie-Tooth-1A and wild-type groups. The majority of these proteins were overexpressed in Charcot-Marie-Tooth-1A. Hierarchical clustering and functional enrichment using Gene Ontology were used to group these proteins based on their biological effects concerning Charcot-Marie-Tooth-1A pathophysiology. Second, proteomic characterization of wild-type rats subjected to sciatic nerve crush was performed sequential window acquisition of all theoretical fragment ion spectra liquid chromatography and mass spectrometry. One month after injury, distal sciatic nerves were collected and analyzed as described above. Out of 459 identified proteins, 92 showed significant differences between sciatic nerve crush and the uninjured wild-type rats used in the first study. The results suggest that young adult Charcot-Marie-Tooth-1A rats (3 months old) develop compensatory mechanisms at the level of redox balance, protein folding, myelination, and axonogenesis. These mechanisms seem insufficient to hurdle the progress of the disease. Notably, response to oxidative stress appears to be a significant feature of Charcot-Marie-Tooth-1A, potentially playing a role in the pathological process. In contrast to the first experiment, the majority of the proteins that differed from wild-type were downregulated in the sciatic nerve crush group. Functional enrichment suggested that neurogenesis, response to axon injury, and oxidative stress were important biological processes. Protein analysis revealed an imperfect repair at this time point after injury and identified several distinguishable proteins. In conclusion, we suggest that peripheral neuropathies, whether of a genetic or traumatic cause, share some common pathological pathways. This study may provide directions for better characterization of these models and/or identifying new specific therapeutic targets.

The macrophage: a key player in the pathophysiology of peripheral neuropathies

Macrophages are present in all mammalian tissues and coexist with various cell types in order to respond to different environmental cues. However, the role of these cells has been underestimated in the context of peripheral nerve damage. More importantly, macrophages display divergent characteristics, associated with their origin, and in response to the modulatory effects of their microenvironment. Interestingly, the advent of new techniques such as fate mapping and single-cell transcriptomics and their synergistic use has helped characterize in detail the origin and fate of tissue-resident macrophages in the peripheral nervous system (PNS). Furthermore, these techniques have allowed a better understanding of their functions from simple homeostatic supervisors to chief regulators in peripheral neuropathies. In this review, we summarize the latest knowledge about macrophage ontogeny, function and tissue identity, with a particular focus on PNS-associated cells, as well as their interaction with reactive oxygen species under physiological and pathological conditions. We then revisit the process of Wallerian degeneration, describing the events accompanying axon degeneration, Schwann cell activation and most importantly, macrophage recruitment to the site of injury. Finally, we review these processes in light of internal and external insults to peripheral nerves leading to peripheral neuropathies, the involvement of macrophages and the potential benefit of the targeting of specific macrophages for the alleviation of functional defects in the PNS.

Curcumin-cyclodextrin/cellulose nanocrystals improve the phenotype of Charcot-Marie-Tooth-1A transgenic rats through the reduction of oxidative stress

The most prevalent form of Charcot-Marie-Tooth disease (CMT type 1A) is characterized by duplication of the PMP22 gene, peripheral dysmyelination and decreased nerve conduction velocities leading to muscle weakness. Recently, oxidative stress was reported as a feature in CMT1A patients. Curcumin exhibits antioxidant activities and has shown beneficial properties on peripheral nerves. However, curcumin presents unfavorable pharmacokinetics. We developed curcumin-cyclodextrin/cellulose nanocrystals (Nano-Cur) to bypass this limitation. The present study investigated the therapeutic potential of Nano-Cur in vitro in Schwann cells (SCs) and in vivo in the transgenic CMT1A rat model. In vitro, Nano-Cur treatment (0.01 μM for 8 h) reduced reactive oxygen species and improved mitochondrial membrane potential in CMT1A SCs. Moreover, Nano-Cur treatment (0.01 μM for 1 week) increased the expression of myelin basic protein in SC/neuron co-cultures. Preliminary in vivo experiments carried out in WT rats showed that intraperitoneal (i.p.) injection of Nano-Cur treatment containing 0.2 mg/kg of curcumin strongly enhanced the bioavailability of curcumin. Afterwards, in 1-month-old male CMT1A rats, Nano-Cur treatment (0.2 mg/kg/day, i.p. for 8 weeks) significantly improved sensori-motor functions (grip strength, balance performance, and mechanical and thermal sensitivities). Importantly, sensory and motor nerve conduction velocities were improved. Further histological and biochemical analyses indicated that myelin sheath thickness and myelin protein expression (myelin protein zero and PMP22) were increased. In addition, oxidative stress markers were decreased in the sciatic nerve and gastrocnemius muscle. Finally, Nrf2 expression and some major antioxidant enzymes were increased in sciatic nerve. Therefore, Nano-Cur significantly improved cellular, electrophysiological, and functional features of CMT1A rats.

Key Developments in the Potential of Curcumin for the Treatment of Peripheral Neuropathies

Peripheral neuropathies (PN) can be triggered after metabolic diseases, traumatic peripheral nerve injury, genetic mutations, toxic substances, and/or inflammation. PN is a major clinical problem, affecting many patients and with few effective therapeutics. Recently, interest in natural dietary compounds, such as polyphenols, in human health has led to a great deal of research, especially in PN. Curcumin is a polyphenol extracted from the root of Curcuma longa. This molecule has long been used in Asian medicine for its anti-inflammatory, antibacterial, and antioxidant properties. However, like numerous polyphenols, curcumin has a very low bioavailability and a very fast metabolism. This review addresses multiple aspects of curcumin in PN, including bioavailability issues, new formulations, observations in animal behavioral tests, electrophysiological, histological, and molecular aspects, and clinical trials published to date. The, review covers in vitro and in vivo studies, with a special focus on the molecular mechanisms of curcumin (anti-inflammatory, antioxidant, anti-endoplasmic reticulum stress (anti-ER-stress), neuroprotection, and glial protection). This review provides for the first time an overview of curcumin in the treatment of PN. Finally, because PN are associated with numerous pathologies (e.g., cancers, diabetes, addiction, inflammatory disease...), this review is likely to interest a large audience.

Peripheral nerve regeneration and intraneural revascularization

Peripheral nerves are particularly vulnerable to injuries and are involved in numerous pathologies for which specific treatments are lacking. This review summarizes the pathophysiological features of the most common traumatic nerve injury in humans and the different animal models used in nerve regeneration studies. The current knowledge concerning Wallerian degeneration and nerve regrowth is then described. Finally, the involvement of intraneural vascularization in these processes is addressed. As intraneural vascularization has been poorly studied, histological experiments were carried out from rat sciatic nerves damaged by a glycerol injection. The results, taken together with the data from literature, suggest that revascularization plays an important role in peripheral nerve regeneration and must therefore be studied more carefully.

Isolation of Astrocytes Displaying Myofibroblast Properties and Present in Multiple Sclerosis Lesions

A wide heterogeneity of lesions can affect the central nervous system (CNS). In all situations where neurons are damaged, including multiple sclerosis (MS), a common reactive astrocytosis is present. Sedimentation field-flow fractionation (SdFFF) was used to sort astrocyte subpopulations. After SdFFF elution, cells, prepared from rat newborn cortex, were cultured and analyzed by immunocytofluorescence for glial fibrillary acidic protein (GFAP) and α-smooth muscle (SM) actin (a specific marker for myofibroblasts) expression. Cell contractile capacity was studied. Samples from patients with MS were also analyzed. Three main fractions (F1, F2, and F3) were isolated and compared with the total eluted population (TP). TP, F1, F2, and F3, contained respectively 74, 96, 12, and 98% of GFAP expressing astrocytes. In F3, astrocytes only expressed GFAP while in F1, astrocytes expressed both GFAP and α-SM actin. In F2 and TP, α-SM actin expression was barely detected. F3-derived cells showed higher contractile capacities compared with F1-derived cells. In one specific case of MS known as Baló's concentric MS, astrocytes expressing both GFAP and α-SM actin were detected. Using SdFFF, a population of astrocytes presenting myofibroblast properties was isolated. This subpopulation of astrocytes was also observed in a MS sample suggesting that it could be involved in lesion formation and remodeling during CNS pathologies.

Neural Stem Cell Properties of an Astrocyte Subpopulation Sorted by Sedimentation Field-Flow Fractionation

Astrocytes encompass a heterogeneous cell population. Using sedimentation field-flow fractionation (SdFFF) method, different, almost pure, astrocyte subpopulations were isolated. Cells were collected from cortex of newborn rats and sorted by SdFFF to obtain different fractions, which were subjected to protein analysis and characterized by immunocytofluorescence. The behavior of the cells was analyzed in vitro, under culture conditions used for neural stem cells. These culture conditions were also applied to cells derived from an adult cortical tissue after traumatic brain injury (TBI). Finally, the astrocytic neural stem-like cells were transplanted in damaged sciatic nerve. Protein analysis indicated a high expression of glial fibrillary acidic protein (GFAP) and vimentin in fraction F3-derived cells. These cells formed neurospheres when cultured with epidermal growth factor and large colonies in a collagen-containing semi-solid matrix. Neurospheres expressed GFAP and nestin and were able in addition to generate neurons expressing MAP2 and oligodendrocytes expressing Olig2. When transplanted in a damaged nerve, cells of F3-derived neurospheres colonized the damaged area. Finally, after TBI in adult rats, cells able to form neurospheres containing a subpopulation of astrocytes expressing vimentin were obtained. Using the SdFFF method, an astrocyte subpopulation presenting stem cell properties was isolated from a newborn rat cortex and from an injured adult rat cortex. The specific activation of this astrocyte subpopulation may provide a potential therapeutic approach to restore lost neuronal function in injured or diseased brain.

The myofibroblast, a key cell in normal and pathological tissue repair

Myofibroblasts are characterized by their expression of α-smooth muscle actin, their enhanced contractility when compared to normal fibroblasts and their increased synthetic activity of extracellular matrix proteins. Myofibroblasts play an important role in normal tissue repair processes, particularly in the skin where they were first described. During normal tissue repair, they appear transiently and are then lost via apoptosis. However, the chronic presence and continued activity of myofibroblasts characterize many fibrotic pathologies, in the skin and internal organs including the liver, kidney and lung. More recently, it has become clear that myofibroblasts also play a role in many types of cancer as stromal or cancer-associated myofibroblast. The fact that myofibroblasts are now known to be key players in many pathologies makes understanding their functions, origin and the regulation of their differentiation important to enable them to be regulated in normal physiology and targeted in fibrosis, scarring and cancer.

Smoothelin, a new marker to determine the origin of liver fibrogenic cells

AIM: To explore this hypothesis that smooth muscle cells may be capable of acquiring a myofibroblastic phenotype, we have studied the expression of smoothelin in fibrotic conditions.

METHODS: Normal liver tissue (n = 3) was obtained from macroscopically normal parts of hepatectomy, taken at a distance from hemangiomas. Pathological specimens included post-burn cutaneous hypertrophic scars (n = 3), fibrotic liver tissue (n = 5), cirrhotic tissue (viral and alcoholic hepatitis) (n = 5), and hepatocellular carcinomas (n = 5). Tissue samples were fixed in 10% formalin and embedded in paraffin for immunohistochemistry or were immediately frozen in liquid nitrogen-cooled isopentane for confocal microscopy analysis. Sections were stained with antibodies against smoothelin, which is expressed exclusively by smooth muscle cells, and α-smooth muscle actin, which is expressed by both smooth muscle cells and myofibroblasts.

RESULTS: In hypertrophic scars, α-smooth muscle actin was detected in vascular smooth muscle cells and in numerous myofibroblasts present in and around nodules, whereas smoothelin was exclusively expressed in vascular smooth muscle cells. In the normal liver, vascular smooth muscle cells were the only cells that express α-smooth muscle actin and smoothelin. In fibrotic areas of the liver, myofibroblasts expressing α-smooth muscle actin were detected. Myofibroblasts co-expressing α-smooth muscle actin and smoothelin were observed, and their number was slightly increased in parallel with the degree of fibrosis (absent in liver with mild or moderate fibrosis; 5% to 10% positive in liver showing severe fibrosis). In cirrhotic septa, numerous myofibroblasts co-expressed α-smooth muscle actin and smoothelin (more than 50%). In hepatocellular carcinomas, the same pattern of expression for α-smooth muscle actin and smoothelin was observed in the stroma reaction surrounding the tumor and around tumoral cell plates. In all pathological liver samples, α-smooth muscle actin and smoothelin were co-expressed in vascular smooth muscle cells.

CONCLUSION: During development of advanced liver fibrosis, a subpopulation of myofibroblasts expressing smoothelin may be derived from vascular smooth muscle cells, illustrating the different cellular origins of myofibroblasts.

The myofibroblast, multiple origins for major roles in normal and pathological tissue repair

Myofibroblasts differentiate, invade and repair injured tissues by secreting and organizing the extracellular matrix and by developing contractile forces. When tissues are damaged, tissue homeostasis must be re-established, and repair mechanisms have to rapidly provide harmonious mechanical tissue organization, a process essentially supported by (myo)fibroblasts. Under physiological conditions, the secretory and contractile activities of myofibroblasts are terminated when the repair is complete (scar formation) but the functionality of the tissue is only rarely perfectly restored. At the end of the normal repair process, myofibroblasts disappear by apoptosis but in pathological situations, myofibroblasts likely remain leading to excessive scarring. Myofibroblasts originate from different precursor cells, the major contribution being from local recruitment of connective tissue fibroblasts. However, local mesenchymal stem cells, bone marrow-derived mesenchymal stem cells and cells derived from an epithelial-mesenchymal transition process, may represent alternative sources of myofibroblasts when local fibroblasts are not able to satisfy the requirement for these cells during repair. These diverse cell types probably contribute to the appearance of myofibroblast subpopulations which show specific biological properties and which are important to understand in order to develop new therapeutic strategies for treatment of fibrotic and scarring diseases.

Mechanisms of pathological scarring: role of myofibroblasts and current developments

Myofibroblasts play a key role in the wound-healing process, promoting wound closure and matrix deposition. These cells normally disappear from granulation tissue by apoptosis after wound closure, but under some circumstances, they persist and may contribute to pathological scar formation. Myofibroblast differentiation and apoptosis are both modulated by cytokines, mechanical stress, and, more generally, cell-cell and cell-matrix interactions. Tissue repair allows tissues and organs to recover, at least partially, functional properties that have been lost through trauma or disease. Embryonic skin wounds are repaired without scarring or fibrosis, whereas skin wound repair in adults always leads to scar formation, which may have functional or esthetic consequences, as in the case of hypertrophic scars, for example. Skin wound repair involves a precise remodeling process, particularly in the dermal compartment, during which fibroblasts/myofibroblasts play a central role. This article reviews the origins of myofibroblasts and their role in normal and pathological skin wound healing. This article focuses on traumatic skin wound healing, but largely, the same mechanisms apply in other physiological and pathological settings. Tissue healing in other organs is examined by comparison, as well as the stromal reaction associated with cancer. New approaches to wound/scar therapy are discussed.

TLR4 signal transduction pathways neutralize the effect of Fas signals on glioblastoma cell proliferation and migration

The Fas pathway is described as an activator of the glioblastoma proliferation by increasing the pathogenicity of this tumour. The lipopolysaccharide (LPS) pathway depending on Toll-like receptor 4 (TLR4) could limit the glioblastoma spreading. Here, Fas and TLR4 pathways were activated in glioblastoma cell lines by an agonist antibody and/or LPS treatment. Activation of the Fas pathway or of the TLR4 pathway induced cell proliferation. However, simultaneous treatment with agonist antibody and LPS decreased proliferation. This anti-proliferative effect was caspase dependent, and a decreased cell migration and matrix metalloproteinase (MMP)-9 expression were also observed. Both TLR4 and MMP-9 were highly expressed in human glioblastoma tissues. These data suggest that TLR4 signal transduction pathways neutralize proliferation and migration induced by Fas pathway activation in glioblastoma cell lines.

Patient-specific electromechanical models of the heart for the prediction of pacing acute effects in CRT: a preliminary clinical validation

Cardiac resynchronisation therapy (CRT) is an effective treatment for patients with congestive heart failure and a wide QRS complex. However, up to 30% of patients are non-responders to therapy in terms of exercise capacity or left ventricular reverse remodelling. A number of controversies still remain surrounding patient selection, targeted lead implantation and optimisation of this important treatment. The development of biophysical models to predict the response to CRT represents a potential strategy to address these issues. In this article, we present how the personalisation of an electromechanical model of the myocardium can predict the acute haemodynamic changes associated with CRT. In order to introduce such an approach as a clinical application, we needed to design models that can be individualised from images and electrophysiological mapping of the left ventricle. In this paper the personalisation of the anatomy, the electrophysiology, the kinematics and the mechanics are described. The acute effects of pacing on pressure development were predicted with the in silico model for several pacing conditions on two patients, achieving good agreement with invasive haemodynamic measurements: the mean error on dP/dt(max) is 47.5±35mmHgs(-1), less than 5% error. These promising results demonstrate the potential of physiological models personalised from images and electrophysiology signals to improve patient selection and plan CRT.

Fibrogenic cell phenotype modifications during remodelling of normal and pathological human liver in cultured slices

BACKGROUND

The debate concerning the potential remodelling and/or reversibility of cirrhotic lesions and biliary fibrosis is still open.

AIMS/METHODS

In this work, we have used the precision-cut liver slice (PCLS) model, which maintains cell-cell and cell-matrix interactions to study, by immunohistochemistry, the behaviour of the different fibrogenic cells, i.e. hepatic stellate cells (HSC) and portal fibroblasts, in cultured (for 1 week) PCLS derived from normal and fibrotic human livers.

RESULTS

In normal liver, before and after culture, α-smooth muscle (SM) actin was present only in the vessel walls. Platelet-derived growth factor (PDGF) receptor-β was expressed before and after culture by portal fibroblasts, and appeared after culture in HSC. Before culture, CD 34 was not expressed in parenchyma, but appeared after culture in sinusoidal endothelial cells. In cirrhotic lesions, before culture, α-SM actin, PDGF receptor-β and Thy-1 were expressed in septa; after culture, α-SM actin expression disappeared but the expression of the PDGF receptor-β and Thy-1 was maintained. In cholestatic liver specimens, α-SM actin, PDGF receptor-β and Thy-1 expression, which was present before culture in enlarged portal areas, disappeared after culture, and apoptosis was detected. In the parenchyma of both cirrhotic and cholestatic livers, the expression of the PDGF receptor-β and of CD 34, which was not observed before culture, was present in HSC and sinusoidal endothelial cells, respectively, after culture.

CONCLUSIONS

These results indicate that during remodelling of pathological tissues in cultured liver slices, the myofibroblastic cells derived from HSC or from portal fibroblasts show different behaviours, suggesting different mechanisms of activation/deactivation.

Involvement of corticostriatal glutamatergic terminals in striatal dopamine release elicited by stimulation of delta-opioid receptors

We have previously shown that striatal dopamine release induced locally by a delta-opioid receptor agonist was totally inhibited by a glutamate N-methyl-D-aspartate receptor antagonist, indicating the involvement of glutamatergic receptors in this effect. The aim of the present study was to specify this mechanism. Firstly, we investigated the effect of [D-Pen2,D-Pen5]-enkephalin (DPDPE) on glutamate release in rats by intrastriatal microdialysis. The infusion of DPDPE (10 microm) enhanced the glutamate content in dialysate by approximately 34%, an effect which did not appear to result from inhibition of glutamate uptake. We then considered the consequences of a unilateral thermocoagulation of the frontal cortex on either glutamate or dopamine release induced by stimulation of delta-opioid receptors 2 days later. This lesion, which decreased the glutamate content in ipsilateral striatum by approximately 30%, totally prevented the increase in dialysate levels of glutamate induced by DPDPE. Moreover, whereas DPDPE (10 microm) was found to increase the striatal dopamine release in intact animals by approximately 59%, this effect was also completely suppressed by the cortical lesion. Finally, we studied the effect of the lesion on the [3H]-DPDPE binding to striatal membranes prepared from the whole striatum. In the ipsilateral striatum a significant decrease in this [3H]-DPDPE binding (by approximately 18%) was found 2 days after the lesion. Our results indicate that the increase in striatal dopamine release induced by DPDPE probably depends on glutamate release from corticostriatal glutamatergic afferents in response to the stimulation of delta-opioid receptors located on terminals of these neurons.

[Traissac voice prosthesis. Apropos of 9 years experiences]

BACKGROUND

Long term results are discussed.

PATIENTS

A retrospective study of 9 years (1/01/89, 1/01/98) concern 107 laryngectomized patients with 9 patients a part from this period, and 30% without prosthesis. Among 80 patients with prosthesis, 57% had received primary TEPs (tracheoesophageal puncture), 21% delayed primary TEPs and 22% secondary TEPs. Oesophageal voice is always learned with tracheoesophageal voice.

RESULTS

We find a success rate (1 month) in 75% of cases, with a maximum follow up time of 8 years (the average is 3 years 1 month). We find a success rate with a long-term result in 66% of cases. Prosthesis removal exists in 30% of cases and oesophageal voice is successfull once out of 3 in this cases. Mean lifetime Traissac's prosthesis is 18 months. After removal, non closed fistulas can exist in 40% of cases, and surgery is always successful.

DISCUSSION

Material Traissac's prosthesis explains extended lifetime.

CONCLUSION

Traissac's prosthesis gave us satisfaction during a use of 8 years.

Absence of complement activation in vitro by sodium meglumine ioxitalamate

The effect of radiographic contrast media on proteins of the complement system in vitro was investigated using protein level measurement and crossed immunoelectrophoresis. Despite the 20% loss of total serum hemolytic activity (CH50) induced by sodium meglumine ioxitalamate (0.5 M), no significant changes in C3c, C3N or B were detected by radial immunodiffusion. These contrast media did not cause electrophoretic conversion of C3, as assessed by the absence of split product, and the small degree of spontaneous C3 conversion (loss of 20% C3N antigen and the presence of two peaks with C3c antigen) which occurred when serum was incubated in polypropylene tubes, was inhibited by the contrast media. The effects of sodium meglumine ioxitalamate and zymosan in vitro on complement activation were compared.