A re-innervated in vitro skin model of non-histaminergic itch and skin neurogenic inflammation: PAR2-, TRPV1- and TRPA1-agonist induced functionality.

Background: Skin, and epidermis, is innervated by sensory nerve fibres. Interactions between them and signal transduction are only partially elucidated in physiological/pathological conditions, especially in pruritus. Objectives: To study the mechanisms involved in pruritus in vitro, we developed a skin explant model re-innervated by sensory neurons. Methods: This model is based on the co-culture of human skin explants and sensory neurons from dorsal root ganglia of rats. Innervation and the expression of protease activated receptor 2 (PAR2), transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin one (TRPA1) was analysed by immunostaining. The response of the model to TRPV1, PAR2 and TRPA1 agonists was analysed by patch-clamp, qPCR and enzyme-linked immunosorbent assay. Results: After 5 days of re-innervating nerve fibres was evidenced in the epidermis. Re-innervation was correlated with decrease of epidermal thickness and the number of apoptotic cells in the tissue. The major actors of non-histaminergic itch (PAR-2, thymic stromal lymphopoietin [TSLP], TSLP-R, TRPA1 and TRPV1) were expressed in neurons and/or epidermal cells of skin explants. After topical exposure of TRPV1-(Capsaicin), TRPA1-(Polygodial) and PAR2-agonist (SLIGKV-NH2) activation of reinnervating neurons could be shown in patch-clamp analysis. The release of TSLP was increased with capsaicin or SLIGKV but decreased with polygodial. Release of CGRP was increased by capsaicin and polygodial but decreased with SLIGKV. Activation by SLIGKV showed a decrease of VEGF; polygodial induced an increase of TSLP, Tumour necrosis factor (TNF) and nerve growth factor and capsaicin lead to a decrease of sema3 and TNF expression. Conclusion: The present model is suitable for studying itch and neurogenic inflammation pathways in vitro. We observed that activation of TRPV1, TRPA1 and PAR-2 leads to different response profiles in re-innervated skin explants.

Itch processing in the brain.

Itch is a sensation defined as the urge to scratch. The central mechanisms of itch are being increasingly studied. These studies are usually based on experimental itch induction methods, which can be classified into the following categories: histamine-induced, induction by other non-histamine chemicals (e.g. cowhage), physically induced (e.g. electrical) and mentally induced (e.g. audio-visual). Because pain has been more extensively studied, some extrapolations to itch can be proposed and verified by experiments. Recent studies suggest that the itch-processing network in the brain could be disrupted in certain diseases. This disruption could be related to the implication of new regions or the exclusion of already engaged brain regions from itch-processing network in the brain.

Functional and anatomical brain connectivity in psoriasis patients and healthy controls: a pilot brain imaging study after exposure to mentally induced itch.

BACKGROUND: Despite the prevalence of psoriasis, the processing of itch in psoriasis and its impact on the central nervous system (CNS) remain unclear. OBJECTIVE: We studied the influence of psoriasis on the CNS using magnetic resonance imaging techniques (fMRI and DTI, respectively) to investigate whether mentally induced itch can modify the functional connectivity or the white matter microstructure of the brain. METHODS: Fourteen patients with chronic psoriasis and 15 healthy controls were recruited. Itch was mentally induced in subjects by videos showing others scratching themselves. RESULTS: The observation of functional connectivity during the viewing the video revealed an interconnected network of brain regions that are more strongly coupled in psoriasis patients than in healthy controls. This network links the cerebellum, the thalami, the anteroposterior cingulum, the inferior parietal lobules, the middle temporal poles and the parahippocampal, hippocampal, lingual and supramarginal gyri. We also found connections with the right precuneus and both left insula and superior temporal gyrus. The DTI analysis showed that chronic itch affects the microstructure of white matter, including the anterior thalamic radiations, the superior and inferior longitudinal fasciculi, the corticospinal tracts, the cingulum, the external capsules, the inferior frontal-occipital fasciculi and both minor and major forceps. CONCLUSION: Our results indicate that there could exist a network which is more interconnected in psoriasis patients. Among two building blocks of this network, the subnetwork encoding the perception and control of itch sensation is more affected than the subnetwork representing mentalizing and empathy. With an approach consisting of measuring microstructural changes at a local level in the brain, we also contradict the findings obtained with global measures which stated that chronic psoriasis cannot alter the anatomy of the brain. This confirms that itchy pathophysiological conditions have similar effects on functional and structural connectivity as those observed in chronic pain.

Exercise testing-based algorithms to diagnose McArdle disease and MAD defects.

OBJECTIVE: As exercise intolerance and exercise-induced myalgia are commonly encountered in metabolic myopathies, functional screening tests are commonly used during the diagnostic work-up. Our objective was to evaluate the accuracy of isometric handgrip test (IHT) and progressive cycle ergometer test (PCET) to identify McArdle disease and myoadenylate deaminase (MAD) deficiency and to propose diagnostic algorithms using exercise-induced lactate and ammonia variations. METHODS: A prospective sample of 46 patients underwent an IHT and a PCET as part of their exercise-induced myalgia and intolerance evaluation. The two diagnostics tests were compared against the results of muscle biopsy and/or the presence of mutations in PYGM. A total of 6 patients had McArdle disease, 5 a complete MAD deficiency (MAD absent), 12 a partial MAD deficiency, and 23 patients had normal muscle biopsy and acylcarnitine profile (disease control). RESULTS: The two functional tests could diagnose all McArdle patients with statistical significance, combining a low lactate variation (IHT: <1 mmol/L, AUC = 0.963, P < .0001; PCET: <1 mmol/L, AUC = 0.990, P < .0001) and a large ammonia variation (IHT: >100 µmol/L, AUC = 0.944, P = .0005; PCET: >20 µmol/L, AUC = 1). PCET was superior to IHT for MAD absent diagnosis, combining very low ammonia variation (<10 µmol/L, AUC = 0.910, P < .0001) and moderate lactate variation (>1 mmol/L). CONCLUSIONS: PCET-based decision tree was more accurate than IHT, with respective generalized squared correlations of 0.796 vs 0.668. IHT and PCET are both interesting diagnostic tools to identify McArdle disease, whereas cycle ergometer exercise is more efficient to diagnose complete MAD deficiency.

Influence of sensory neuropeptides on human cutaneous wound healing process.

BACKGROUND: Close interactions exist between primary sensory neurons of the peripheral nervous system (PNS) and skin cells. The PNS may be implicated in the modulation of different skin functions as wound healing. OBJECTIVE: Study the influence of sensory neurons in human cutaneous wound healing. METHODS: We incubated injured human skin explants either with rat primary sensory neurons from dorsal root ganglia (DRG) or different neuropeptides (vasoactive intestinal peptide or VIP, calcitonin gene-related peptide or CGRP, substance P or SP) at various concentrations. Then we evaluated their effects on the proliferative and extracellular matrix (ECM) remodeling phases, dermal fibroblasts adhesion and differentiation into myofibroblasts. RESULTS: Thus, DRG and all studied neuromediators increased fibroblasts and keratinocytes proliferation and act on the expression ratio between collagen type I and type III in favor of collagen I, particularly between the 3rd and 7th day of culture. Furthermore, the enzymatic activities of matrix metalloprotesases (MMP-2 and MMP-9) were increased in the first days of wound healing process. Finally, the adhesion of human dermal fibroblasts and their differentiation into myofibroblasts were promoted after incubation with neuromediators. Interestingly, the most potent concentrations for each tested molecules, were the lowest concentrations, corresponding to physiological concentrations. CONCLUSION: Sensory neurons and their derived-neuropeptides are able to promote skin wound healing.

[Classification of urinary calculi in a pediatric population from Brittany]. / Proposition de "profils types" des calculs urinaires dans une population pédiatrique bretonne.

INTRODUCTION: Urinary lithiasis in children is relatively seldom in France as in industrialized countries. The determination of their etiology based on their composition may lead to a better treatment. METHOD: One hundred and eight urinary calculi from 6 months through 18-year-old children were analyzed by using spectrophotometry, in order to specify their structure. Six groups were evidenced through a multidimensional analysis based on the presence of components weighing at least 5% of the total. RESULTS: The youngest children affected were mostly boys, and the sex ratio switched after 12.5 years. Above 14 years of age, the number of calculi significantly raised. Their composition varied with the gender, and their localization with the age. Finally a correlation between infection and composition of the calculus was shown in our study. CONCLUSION: The classification of calculi among six groups according to their composition, along with clinical informations and morphologic studies, has proven its value in determining the etiology of the lithiasis. These data help to better understand the kind of lithiasis that may be observed and the physiopathology of the mechanism explaining it from the gender and age.

Body mass index, a major confounder to insulin resistance association with unprovoked venous thromboembolism. Results from the EDITH case-control study.

Shared risk factors help explain the association between venous thromboembolism (VTE) and atherothrombosis. The potential association between insulin resistance and VTE has been poorly evaluated. Thus, we aimed to assess the association between insulin resistance and VTE in the EDITH hospital-based case-control study. Between May 2000 and December 2004, 677 patients with unprovoked VTE and their age- and sex-matched controls were included. Fasting glycaemia and insulinaemia were measured and insulin resistance was estimated with the homeostasis model assessment of insulin resistance (HOMA-IR) equation. The association between HOMA-IR and VTE was determined in non-diabetic patients in a quintile-based analysis. A total of 590 non-diabetic cases (median age 73.0 years, 255 men) and 581 non-diabetic controls (median age 72.0 years, 247 men) were analysed. There was a trend for a higher median level of HOMA-IR index in cases than in controls (1.21 [interquartile range 0.84-2.10] vs1.19 [interquartile range 0.72-2.02], p=0.08). The unadjusted analysis showed an increased risk of unprovoked VTE associated with increasing HOMA-IR (odds ratio [OR] 1.53; 95% confidence interval [CI] 1.00-2.34 for the highest quintile of HOMA-IR compared with the first quintile). Adjustment for lipid lowering drugs and antiplatelet agents use slightly modified the association (OR 1.51; 95% CI 0.97-2.34). When body mass index was added in the adjusted model, HOMA-IR was no longer associated with VTE (OR 1.08; 95% CI 0.67-1.73). Our results highlight the role of body mass index in the association between cardiovascular risk factors and VTE.

[Adaptation of free and total plasma carnitine determination on the Dimension HM, X-Pand model (Dade Behring)]. / Adaptation des dosages plasmatiques de carnitine libre et totale sur automate Dimension HM, modèle X-Pand (Dade Behring).

L-carnitine is a quaternary ammonium compound that facilitates long-chain fatty acids crossing through the mitochondrial membrane allowing their beta-oxidation. Human pathologies relatives to carnitine are mainly deficiencies, with myopathy and lipids metabolism disorders. The aim of this study was to validate the free and total carnitine plasmatic level measurement using the Dimension HM, X-Pand model analyzer (Dade Behring). Free carnitine was directly determined on plasma samples, deproteinized by using ultrafiltration, whereas total carnitine was measured after alkaline hydrolysis. Within-day and between-day imprecision were < 4,00 and 9,00 % respectively. The method is linear through 250,00 micromol/L and the limit of quantification is 3,00 micromol/L. Our method was correlated to tandem mass spectrometry (r = 0,956 for free and total carnitine). Recovery of free and total carnitine from spiked plasmas was > 99 %. On board stability of cartridge (5 days) and of calibration (at least 30 days) are in agreement with a method easily adaptable in routine laboratories.

[Evaluation of the renal function in cardiac surgery with CPB: role of the cystatin C and the calculated creatinine clearance]. / Evaluation de la fonction rénale périopératoire en chirurgie cardiaque: rôle de la cystatine C et de clairance de la créatinine calculée.

OBJECTIVES: The evaluation of the renal function in cardiac surgery is difficult. The gold standard remains the creatinine clearance in clinical practice. Cystatin C was recently proposed in order to evaluate the renal function. The aim of our study was to evaluate the cystatin C in cardiac surgery with CPB. PATIENTS AND METHODS: After informed consent and ethical committee agreement, 60 patients operated in cardiac surgery with CPB were prospectively included. Cystatin C,measured and calculated (Cockcroft and MDRD methods) creatinine were compared with the Student t-test and with the Bland and Altman method. p<0,05 was considered as a significant threshold. RESULTS: The reproducibility of the calculated creatinine clearance was better when the urinary collecting time was below 400 minutes. The estimation of the creatinine clearance by the Cockcroft and MDRD methods is better when the clearance is low. A significant correlation between the creatinine clearance and the cystatin C does exist, but the correlation coefficient was low. In case of acute renal dysfunction, the increase of the creatinine occurred earlier than the increase of the cystatin C. CONCLUSION: In cardiac surgery with CPB, the evaluation of the renal function was not improved by the cystatin C.

[Metabolic acidosis after cardiac surgery with cardiopulmonary bypass revisited with the use of the Stewart acid-base approach]. / Evaluation de la théorie de Stewart lors de l'acidose métabolique survenant après chirurgie cardiaque sous circulation extracorporelle.

INTRODUCTION: According to the Stewart approach of acid-base regulation, chloride from either volume replacement or cardiopulmonary bypass (CPB) priming solution may induce metabolic acidosis. The alternative hypothesis stands in volume dilution with solutions free of bicarbonate. OBJECTIVES: Evaluate the acid-base status of patients undergoing cardiac surgery with CPB priming containing chloride and bicarbonate. MATERIAL AND METHODS: Prospective study. METHODS: Twenty-eight patients were prospectively included. Priming of CPB contained 47.4 mmol/l of bicarbonate and 97.7 mmol/l of chloride. Arterial blood samples were taken at 3 timings: prior (T1) and after (T2) CPB, and on arrival in the ICU (T3). Following measurements were performed: Na(+), K(+), Cl(-), Mg(++), Ca(++), phosphates, albumin, lactate and arterial blood gases. RESULTS: After CPB respiratory acidosis was observed. There was a significant increase of chloride with a decrease in apparent strong ion difference (SIDa). At the same time bicarbonate and base excess (BE) remained constant. A significant but weak correlation between BE and SIDa existed (r(2) = 0.06, p=0.024). On the contrary, no correlation was found between variations of BE and SIDa. However, the correlation was stronger between values and variations of bicarbonate and BE (respectively r(2)=0.605, p<0.0001 and r(2)=0.495, p<0.0001). CONCLUSION: No metabolic acidosis occurred after cardiac surgery when CPB was primed with bicarbonate. Therefore, it appears that chloride administration is not the main mechanism being involved in the acid-base regulation. This reinforces the hypothesis that metabolic acidosis during CPB may mainly be due to dilution of bicarbonate.

[Etiological orientation from the analysis morphological and constitutional of urinary stones in Conakry]. / Orientation etiologique a partir de l'analyse morphologique et constitutionnelle des lithiases urinaires a Conakry.

INTRODUCTION: The epidemiological profile of urinary stones varies from region of the world to another according to food habit and certain enviromental factors. The aim of our study was to establish an etiological approach of the urinary lithiasis collected in Conakry by morphological and constitutional analysis. MATERIALS AND METHODS: It was a prospective study from january 1 rst 2003 to january 1 rst 2004 concerning all the stones collected. They were analysed by binocular magnifying glass and infra red spectrophotometry of Fourier. RESULTS: During the period, 18 patients were observed (14 male, 4 femele) of 27.4 +/- 4 years old (from 2 to 69) living mainly in urban environment. From these patients 28 stones were collected; 12 spontaneously and 16 surgicaly. Their composition were whewellite (36%), struvite (29%), carbapatite (14%), urates (14%) and weddellite (7%). In Conakry stones come mainly from hyperoxaluria and urinary tract infection; hypercalciuria is uncomon. CONCLUSION: The urinary calculations examined among patients show in the adult a prevalence of elements in favour of a hyperoxalurie and a notable context of urinary infections in particular in the child; the pure hypercalciurie remains negligible in Conakry, we plan to lead a thorough work to the national scales.

Topical imiquimod treatment of lentigo maligna: clinical and histologic evaluation.

We have treated extensive lentigo maligna in two elderly patients with Imiquimod 5% (Aldara). It was applied 3 times weekly, for 3 to 5 months. Clinical and histological remission was observed over 13 months of follow-up care. Tolerance was good. We suggest that topical imiquimod could be an interesting therapeutic alternative.

[Epidemiologic study of urinary calculi in Western France]. / Etude épidémiologique des calculs urinaires dans l'Ouest de la France.

OBJECTIVES: An epidemiologic study of urinary calculi (N = 1843) was conducted in Western France: distribution according to the main chemical compounds, age and sex. Comparison with the results of a study with national recruitment (N = 10,617) and a study with regional recruitment (N = 1774). METHOD: The study involved 1843 stones characterized beforehand by morphological analysis associated with infra-red spectrophotometry (FTIR). If analysis of the composition of the stones was carried out on the totality of calculi, studies related to age and sex included only 1583 cases. Comparison of percentages was made using chi 2 test. RESULTS: The composition in main compounds of calculi was comparable with the results of other studies; minor significant compounds presented great differences, raising the problem of interpretation of the infra-red spectra of the latter. Hence, our work was directed towards the analysis of the major compounds and we showed, like most authors, that monohydrate calcium oxalate is predominant in male (46%) as well as in females (37%). Calculi average sex-ratio was 2.19 but dehydrated calcium oxalate sex-ratio was 4.42, suggesting that this compound is found mainly in men. Conversely, for the majority of phosphate stones, the sex-ratio was lower or equal to one, indicating that they predominate in women. Infectious calculi (particularly struvite calculi) appeared slightly more frequent in our population than in other studies, whereas the number of uric acid calculi was lower. This, however, remains to be confirmed. CONCLUSION: The population studied was not significantly different from the national population regarding lithiasis, except perhaps for uric acid and struvite calculi, despite specific regional differences in diet and the role of nutritional factors in lithogenesis.

Ontogeny of steroid metabolizing enzymes in rat oligodendrocytes.

Rat oligodendroglial cells were isolated from newborn and developing brains and used immediately after, for quantification of steroid metabolizing activities. Oligodendrocytes (Ol) and their progenitor cells were incubated with [(14)C] testosterone, [(14)C] progesterone, [(14)C] pregnenolone or [(14)C] dehydroepiandrosterone (DHEA). Oligodendrocytes and their progenitor cells expressed different steroid metabolizing enzymes. The main activities were 5 alpha reduction of testosterone and progesterone and 3 beta hydroxy steroid dehydrogenase-isomerase which transformed pregnenolone into progesterone and DHEA into Delta 4 androstenedione. 5 alpha reductase activity increased in male and female rats in parallel with testosterone or progesterone. Contrary to this, 3 beta hydroxysteroid dehydrogenase-isomerase activity was found to be high in the young rat and to decrease when testosterone and progesterone plasma concentration increased.

Reactive microglia in dysmyelination and demyelination.

The relationship between microglial activation and dysmyelination/demyelination was analyzed in a long-lived myelin mutant, the Long Evans shaker (les) rat, which exhibits early dysmyelination and a later loss of abnormal myelin sheaths. A microglial reaction characterized by progressive morphological transformation and increasing cell density was localized exclusively to white matter during postnatal 2-4 weeks, suggesting a microglial response to dysmyelination and oligodendroglial pathology. A further microglial reaction as marked by microglial expression of MHC II and a concomitant expression in the brain and spinal cord of mRNA for interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), and inducible nitric oxide synthase (iNOS) began around 4 weeks when the remaining myelin was lost. Ultrastructurally, activated microglia ingested numerous myelin figures, suggestive of active phagocytosis. Thus, this study indicates that microglial reaction is graded in chronic neurological disorders and suggests that MHC II expression marks a functional change of activated microglia.

Thyroid hormone receptor isoforms are sequentially expressed in oligodendrocyte lineage cells during rat cerebral development.

In the mammalian brain, thyroid hormones regulate myelination. Their actions are mediated by interactions with nuclear receptors that function as ligand-regulated transcription factors. Two genes, alpha and beta, encode different isoforms, of which only the beta and alpha1 isoforms are authentic nuclear triiodothyronine (T3)-receptors (NT3R). In agreement with the important role of T3 on myelination and oligodendrocyte generation, the presence of NT3Rs has been reported in oligodendrocytes and their precursors. We and others have shown that both progenitors and oligodendrocytes in vitro express the alpha1 and alpha2 isoforms, but the expression of the beta1 isoform is confined to differentiated oligodendrocytes, suggesting that they have different functions. To establish if this is the case during development in vivo, we have studied NT3R isoform expression in glial cells isolated by density gradient centrifugation from rat brains of various ages. We report the presence of the alpha1 NT3R and its variant alpha2, but not that of the beta1 isoform, in newborn rat glial progenitors. The pattern of expression of beta1, both at the level of mRNA and protein, parallels the increase in the number of oligodendrocytes. We found a significant change in the kinetic parameters of [125I]-T3 binding to NT3Rs in these cells during the first month of life, consisting of an increase in the binding capacity that peaks with myelination, and a significative decrease in Kd that coincides with the switch from the alpha to the beta1 isoform. Thus, the expression of NT3R isoforms in the rat oligodendrocyte lineage changes radically from the alpha to the beta1 isoform during the period when oligodendrocytes differentiate from progenitors.