Navigating the multifaceted intricacies of the Na+-Cl- cotransporter, a highly regulated key effector in the control of hydromineral homeostasis

The Na+-Cl- cotransporter (NCC; SLC12A3) is a highly regulated integral membrane protein that is known to exist as three splice variants in primates. Its primary role in the kidney is to mediate the cosymport of Na+ and Cl- across the apical membrane of the distal convoluted tubule. Through this role and the involvement of other ion transport systems, NCC allows the systemic circulation to reclaim a fraction of the ultrafiltered Na+, K+, Cl-, and Mg+ loads in exchange for Ca2+ and [Formula: see text]. The physiological relevance of the Na+-Cl- cotransport mechanism in humans is illustrated by several abnormalities that result from NCC inactivation through the administration of thiazides or in the setting of hereditary disorders. The purpose of the present review is to discuss the molecular mechanisms and overall roles of Na+-Cl- cotransport as the main topics of interest. On reading the narrative proposed, one will realize that the knowledge gained in regard to these themes will continue to progress unrelentingly no matter how refined it has now become.

35 Pharmacologic management of children with juvenile idiopathic arthritis in Batna, Algeria

Background

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in childhood and is usually treated with non-steroidal anti-inflammatory drugs or disease-modifying anti-rheumatic drugs. The outcome in patients with JIA has markedly improved with the advent of biologic drugs.

Objectives

The aim of this study was to describe treatments prescribed for children with JIA in Batna, Algeria.

Methods

A multicentre retrospective and descriptive study was conducted in Batna health centers (public and private sectors), over a seven-year period from January 2013 to December 2019, based on (JIA patient’s data collection). As public sector source, we referred to the department of pediatrics of the university hospital center (CHU Benflis Touhami Batna), and as private sector source, we referred to private adult rheumatologists based in Batna.

Results

The study included a total of 69 cases of JIA that were being followed in Batna health centers over the study period. Treatment modalities used for these patients included non-steroidal anti-inflammatory drugs (NSAIDs) in 54 patients (79.4%), steroids (prednisolone) in 37 patients (54.4%), conventional disease-modifying anti-rheumatic drug (c-DMARDs) in 51 patients (72.5%), biologic agents in 11 (15.9%) and intra articular injections in 17 patients (24.6%). The most frequently used c-DMARDs was methotrexate 42 (63.7%). The mean maximal dose reached was 7.5 mg (range 2.5–15). It was associated to other c-DMARDs in 2 cases. Sulfasalazine was used in 8 cases, Leflunomide in 1 case, and Hydroxychloroquine in 1 case. Biologics were used in 11 cases (15.9%).

RF-positive polyarthritis 4(50%), RF-negative polyarthritis 3 (33.3), systemic arthritis 2 (33.3) were the groups that most commonly needed a biological therapy. Biologics included Rituximab (n = 2), Tocilizumab (n = 1), Anakinra (n = 1), Etanercept (n = 1) and Infliximab (n = 1). The (mean duration of the disease evolution at the initiation of the biological agent) was 4.8 ± 5.4 years (range 0.5–8 years). At the time of enrolment, 31 patients (44.9%) were in remission: 20 patients (29%) were under treatment and 11 patients (15.9%) were not, while 12 patients (17.4%) had active disease.

Conclusion

A high proportion of children presenting with JIA received cDMARDs. Biologics were needed in a few cases.

Disclosure of Interest

None declared

POS0497 A RELIABILITY EXERCISE USING CONSENSUAL DEFINITIONS FOR THE ULTRASONOGRAPHY OF THE SHOULDER IN RHEUMATOID ARTHRITIS

Background:

Although numerous clinical tests for the diagnosis of painful shoulder are available, differentiating articular from periarticular lesions may be difficult in daily practice. Fortunately, the precise diagnosis of shoulder pain in RA benefited from a reliable imaging modality to detect its exact origin as ultrasonography (US).

Objectives:

This study aimed to assess the intraobserver and interobserver reliabilities of the ultrasonographic findings for patients with established RA having shoulder pain in a patient-based exercise among maghrebian rheumatologists experts on US.

Methods:

A total of 7 operators examined 10 patients in 2 rounds independently and blindly of each other.

Each patient underwent a US scanning of the painful shoulder in four sites based on US technical guidelines of the European society of musculoskeletal radiology: long head of Biceps (LHB), subscapularis recess, posterior recess and axillary recess. The presence of a subdeltoid or subcoracoid bursitis or the presence of transfixiant tear of the suprasupinatus were notified if present. Intra and inter-observer reliabilities were calculated.

Results:

Intraobserver reliability was excellent for GS synovitis in subscapularis and posterior recesses (k=0.91 for both) and for subcoracoid bursitis (k=0.81). It was good in case of presence of a subdeltoid bursitis (k=0.79), transfixiant tear of the suprasupinatus (k=0.65), GS synovitis and effusion in LHB (k=0.67 and 0.6 respectively) and subdeltoid bursitis (k= 0.79). Interobserver reliability was good for PD for LHB signals searched longitudinally (k=0.78) and transversally (k=0.78). It was moderate for GS for LHB synovitis (k=0.55). Interobserver agreement was poor for effusion and GS synovitis for subscapularis, posterior and axillary recesses. It was very poor and/or absent for PD signals in these recesses.

Conclusion:

US is a reliable imaging tool for shoulder in RA especially with regard to LHB effusion, GS and PD synovitis. Interobserver reliability of subscapularis, posterior and axillary recesses could be optimized by standardization of sites to assess.

References:

[1]Bruyn G a. W, Naredo E, Möller I, Moragues C, Garrido J, de Bock GH, et al. Reliability of ultrasonography in detecting shoulder disease in patients with rheumatoid arthritis. Ann Rheum Dis 2009;68:357–61.

Disclosure of Interests:

None declared

AB0243 CONSIDERING THE COMBINATION OF TWO BIOLOGICS IN CASE OF FAILURE OF THE MONOTHERAPY IN JUVENILE ONSET RHEUMATOID ARTHRITIS

Background:

The management of rheumatoid arthritis refractory to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) is currently well codified and includes different types of biologics and even targeted sDMARDs. A rotation of biologic therapies is recommended in order to better control the disease.

Methods:

We report the case of a 20-year-old patient followed in our hospital for the management of a deforming and erosive seropositive rheumatoid arthritis (FR +, ACPA +) with a juvenile onset at the age of 8 years. The diagnosis of an immunopositive polyarticular form of JIA was retained in 2010 (9 years old); the patient was treated with methotrexate (MTX) at a dose of 10 mg per week and methylprednisolone at doses varying between 4 and 10 mg per day. Following the failure of MTX, etanercept was introduced for 6 months without success, followed by tocilizumab in 2012 at a dose of 8mg/kg/month for a year, without good response. In 2014, a course of rituximab (RTX) at a dose of 2 shots of 500mg, 2 weeks apart was prescribed followed 9 months later by etanercept at a dose of 50 mg a week for 3 years then by adalimumab (40mg/ week) because of the multiple treatment failures.

In 2018, the repetition of RTX at a dose of 1g, renewed 15 days later, improved the patient for only 3 months. Then, a combination of two biologics, namely RTX (2 x 1g, 15 days apart) and adalimumab 1 month later (40mg / week) was received by the patient with a good response at 3 months. The latter was maintained for 7 months even after stopping the adalimumab following confinement for COVID-19. In September 2020, flares occurred and the adalimumab (ADA) has been delivered but without success during 3 months, stopped later for a benign form of COVID-19 (15 months after RTX). In January 2021, the association RTX + ADA was given again and we hope that it will be as effective as the first prescription.

Results:

The clinical and biological severity of our patient’s rheumatoid arthritis led us to give a combination of two biological treatments. Indeed, we do not have other therapeutic classes to deliver to her, that encouraged us to rotate between all the available biological therapies in our country. The combination of a CD20 inhibitor (RTX) with a TNF blocker (ADA) was safe and made possible, for the first time, the achievement of clinical and biological remission during 7 months, even after stopping the TNF blocker. Greenwald et al. reported the safety of the combination of RTX + TNF inhibitors in a randomized clinical trial in 51 patients. Its efficacy, a secondary goal of the study, was suggested at 24 weeks by the percentage of ACR 20 and ACR 50 responses that was greater than in the RTX placebo group.

Conclusion:

The combination of RTX with a TNF blocker can be a real alternative therapy in rheumatoid arthritis with failure to a biological monotherapy.

Disclosure of Interests:

None declared

Magnetic mesoporous silica nanostructures: investigation of magnetic properties

Magnetic mesoporous silica (MS) nanocomposites provide the possibility of generating multi-functional objects for application in different technological areas. This paper focuses on the magnetic properties of nanocomposites constituted by spinel iron oxide nanoparticles (magnetic nanoparticles (MNPs), < D > ≈ 8-9 nm) embedded in an MS matrix. The mesoporous structure of the silica matrix and the presence of the nanoparticles inside clearly emerge from transmission electron microscopy (TEM) measurements. Low temperature (5 K) field-dependent magnetization measurements reveal saturation magnetization (M_S ) close to bulk value (M _S bulk ∼ 90 emu g^-1) for both MNPs and MNP/MS nanocomposites, indicating that the presence of silica does not affect the magnetic features of the single MNPs. Moreover, the dependence of the remanent magnetization on field (i.e. δM plots) at low temperature has shown a small but evident decrease of interaction in an MNP/MS sample with respect to MNP samples A m² Kg^-1. Finally, a partial orientation of the easy axis is observed when the MNPs are embedded in the silica matrix.

Multiple Facets and Roles of Na+-K+-Cl−Cotransport: Mechanisms and Therapeutic Implications

The Na+-K+-Cl−cotransporters play key physiological and pathophysiological roles by regulating the membrane potential of many cell types and the movement of fluid across a variety of epithelial or endothelial structures. As such, they should soon become invaluable targets for the treatment of various disorders including pain, epilepsy, brain edema, and hypertension. This review highlights the nature of these roles, the mechanisms at play, and the unresolved issues in the field.

Staphylococcus capitis isolated from bloodstream infections: a nationwide 3-month survey in 38 neonatal intensive care units

To increase the knowledge about S. capitis in the neonatal setting, we conducted a nationwide 3-month survey in 38 neonatal intensive care units (NICUs) covering 56.6% of French NICU beds. We demonstrated 14.2% of S. capitis BSI (S.capBSI) among nosocomial BSIs. S.capBSI incidence rate was 0.59 per 1000 patient-days. A total of 55.0% of the S.capBSIs were late onset catheter-related BSIs. The S. capitis strains infected preterm babies (median gestational age 26 weeks, median birth weight 855 g). They were resistant to methicillin and aminoglycosides and belonged to the NRCS-A clone. Evolution was favorable in all but one case, following vancomycin treatment.

THU0191 HAS THE DOSE OF METHOTREXATE IN RHEUMATOID ARTHRITIS BEEN OPTIMIZED BEFORE INITIATING BIOLOGICAL TREATMENT? RESULTS OF AN ALGERIAN MULTICENTER STUDY

Background:

Methotrexate (MTX) is the gold standard treatment for rheumatoid arthritis (RA). The international guidelines recommend optimizing its dose before the introduction of a biologic treatment in cases where it is well tolerated1.

Objectives:

The objective of this study is to evaluate the dose of MTX before the initiation of biological treatment in RA patients with MTX ineffectiveness.

Methods:

This is a multicenter, cross-sectional, prospective study including adults RA, over a period of 6 months (January-June 2019). We collected the following data: sex, age, comorbidities (diabetes, hypertension), rate of RF and ACPA, dose of MTX, rate of patients on corticosteroids, Disease Activity Score (DAS 28-vs), Health Assessment Questionnaire (HAQ) and SHARP Score.

Results:

Number of patients: 239 (187 women / 52 men); average age: 48.3 years (19 - 81); average duration of the disease: 13.6 ± 8.2 years. Comorbidities: arterial hypertension (14,6 %) - diabetes (13 %),The RF were positive in 59.8%. The average value of ACPA is 228.76 ± 287.08 IU / L, positive in 73% case. The average DAS28vs is 4.77 ± 1.46 (0.77 - 12.26). The average modified SHARP 111.67 ± 98.16 (0-448), the average HAQ is 1.13 ± 0.82 (0 - 2.87). 86.7% of patients are under corticosteroids.Only 18.5% of patients had a dose of MTX between 20 and 25 mg / week. the remaining 82% of patients the average dose of MTX was 14 mg / week (10-18.5).

Conclusion:

These results suggest that the dose of MTX was not optimized before the initiation of biotherapy in the majority of patients with RA.

References:

[1]Smolen JS, Landewé R, Bijlsma J, et al.EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2016 updateAnnals of the Rheumatic Diseases2017;76:960-977.

[3]Claire Daiena, Charlotte Huac, Cécile Gaujoux-Viala, et al. Update of French society for rheumatology recommendations for managing rheumatoid arthritis. Joint Bone Spine 86 (2019) 135–150

[2]Singh JA, Saag KG, Bridges SL Jr, et al. 2015 American College of Rheumatology Guideline for the Treatment of Rheumatoid Arthritis. Arthritis Care Res. 2016 Jan;68(1):1-25.

Disclosure of Interests:

None declared

K+-Cl- cotransporter 1 (KCC1): a housekeeping membrane protein that plays key supplemental roles in hematopoietic and cancer cells

During the 1970s, a Na+-independent, ouabain-insensitive, N-ethylmaleimide-stimulated K+-Cl- cotransport mechanism was identified in red blood cells for the first time and in a variety of cell types afterward. During and just after the mid-1990s, three closely related isoforms were shown to account for this mechanism. They were termed K+-Cl- cotransporter 1 (KCC1), KCC3, and KCC4 according to the nomenclature of Gillen et al. (1996) who had been the first research group to uncover the molecular identity of a KCC, that is, of KCC1 in rabbit kidney. Since then, KCC1 has been found to be the most widely distributed KCC isoform and considered to act as a housekeeping membrane protein. It has perhaps received less attention than the other isoforms for this reason, but as will be discussed in the following review, there is probably more to KCC1 than meets the eye. In particular, the so-called housekeeping gene also appears to play crucial and specific roles in normal as well as pathological hematopoietic and in cancer cells.

Physiological roles and molecular mechanisms of K+ -Cl- cotransport in the mammalian kidney and cardiovascular system: where are we?

In the early 80s, renal microperfusion studies led to the identification of a basolateral K⁺ -Cl^- cotransport mechanism in the proximal tubule, thick ascending limb of Henle and collecting duct. More than ten years later, this mechanism was found to be accounted for by three different K⁺ -Cl^- cotransporters (KCC1, KCC3 and KCC4) that are differentially distributed along the renal epithelium. Two of these isoforms (KCC1 and KCC3) were also found to be expressed in arterial walls, the myocardium and a variety of neurons. Subsequently, valuable insights have been gained into the molecular and physiological properties of the KCCs in both the mammalian kidney and cardiovascular system. There is now robust evidence indicating that KCC4 sustains distal renal acidification and that KCC3 regulates myogenic tone in resistance vessels. However, progress in understanding the functional significance of these transporters has been slow, probably because each of the KCC isoforms is not identically distributed among species and some of them share common subcellular localizations with other KCC isoforms or sizeable conductive Cl^- pathways. In addition, the mechanisms underlying the process of K⁺ -Cl^- cotransport are still ill defined. The present review focuses on the knowledge gained regarding the roles and properties of KCCs in renal and cardiovascular tissues.

Fast detection of both O157 and non-O157 shiga-toxin producing Escherichia coli by real-time optical immunoassay

Among bacterial pathogens involved in food-illnesses, seven serogroups (O26, O45, O103, O111, O121, O145 and O157) of Shiga-toxin producing Escherichia coli (STEC), are frequently identified. During such outbreak, and due to the perishable property of most foodstuff, the time laps for the identification of contaminated products and pathogens is thus critical to better circumvent their spread. Traditional detection methods using PCR or culture plating are time consuming and may present some limitations. In this study, we present a multiplexed immunoassay for the optical detection of most commonly enterohemorrhagic E. coli serogroups: O26, O45, O103, O111, O121, O145 and O157:H7 in a single device. The use of Surface Plasmon Resonance imaging not only enabled the label-free analysis of the samples but gave results in a real-time manner. A dedicated protocol was set up for the detection of both low contaminating bacterial concentrations of food samples (5 CFU per 25 g) and postenrichment aliquots. By combining one single device for the detection of O157 and non-O157 STEC in a label-free manner, this rapid approach may have an important economic and societal impact.

SIGNIFICANCE AND IMPACT OF THE STUDY

This article presents a simple-to-operate immunoassay for the specific detection of Shiga-toxin producing Escherichia coli (STEC). This approach consists in the on-chip assay detection of viable cells on a specifically designed antibody microarray. By skipping any enrichment step and avoiding the use of labelling agent, this approach based on the Surface Plasmon Resonance imaging of the microarrays turns out to be much faster and more cost effective by comparison with standardized methods.

[A paraneoplastic Sharp syndrome reversible after resection of a benign schwannoma: a paraneoplastic syndrome?]

Paraneoplastic syndromes commonly occur in malignancies and often precede the first symptoms of the tumor. By definition, paraneoplastic syndromes are only associated with malignancies although some exceptions have been reported, occurring with benign tumors. We report a patient presenting with a clinical and serological Sharp syndrome, followed a few months later by a cervical schwannoma. Curative surgical resection of the mass resulted in a clinical and serological healing from the Sharp syndrome. To our knowledge, this is the first report of a benign schwannoma complicated by a possible paraneoplastic Sharp syndrome.

Hospital washbasin water: risk of Legionella-contaminated aerosol inhalation

The contamination of aerosols by washbasin water colonized by Legionella in a hospital was evaluated. Aerosol samples were collected by two impingement technologies. Legionella was never detected by culture in all the (aerosol) samples. However, 45% (18/40) of aerosol samples were positive for Legionella spp. by polymerase chain reaction, with measurable concentrations in 10% of samples (4/40). Moreover, immunoassay detected Legionella pneumophila serogroup 1 and L. anisa, and potentially viable bacteria were seen on viability testing. These data suggest that colonized hospital washbasins could represent risks of exposure to Legionella aerosol inhalation, especially by immunocompromised patients.

Urinary markers of workers chronically exposed to mercury vapor

The effects of chronic mercury intoxication on urinary markers in workers from northeast Algeria were investigated. Workmen were chosen from highly and moderately mercury-exposed factories, while controls were selected from a nonexposed site. The number of proteinuria cases were higher in the highly exposed subjects, although the nature (glomerular or tubular) of proteinuria remains unclear. However, it appears difficult to assess the degree of renal disturbance among the different exposure levels, such as the amount of excreted proteins, which have not clearly reflected the kidney lesion severity. The results also reveal that urine acidity increased progressively with increased levels of exposure, while a remarkable inverse relationship between urinary pH and urinary Hg in the highly exposed workers has been recorded. Furthermore, the significant differences in blood and urinary mercury concentrations of the three sites reflect the dose-response relationships.

[Absence of interaction between thiomersal and aluminum occlusion chambers]

BACKGROUND

Positive patch tests to thiomersal are frequent, but of little relevance. Interaction between aluminium occlusive chambers and the mercury of thiomersal may elicit skin irritation and cause false positive results.

METHODS

Between January 1998 and May 1999, the patients were simultaneously patch tested with aluminium and plastic chambers. Positive skin tests were compared.

RESULTS

Seventeen of 213 subjects showed positive tests: 15 with the 2 materials, 1 only for the aluminium chamber, 1 for the plastic chamber.

DISCUSSION

The results did not differ for the two materials. We concluded that positive reactions observed were not caused by interaction between aluminium and thiomersal.

Clinical efficacy and safety of a topical combination of retinaldehyde 0.1% with erythromycin 4% in acne vulgaris

The objective of this randomized, controlled, multicentre study was to assess the efficacy and safety of a topically applied retinaldehyde 0.1% gel in combination with a topical erythromycin 4% lotion for the treatment of acne vulgaris. Treatment consisted of applying either retinaldehyde or its vehicle every morning and erythromycin every evening for 8 weeks. Efficacy parameters were sequential lesion counts for papules and pustules, and a 6-point semiquantitative scale for comedones and microcysts. Safety parameters were local tolerance and adverse events. Of 74 recruited patients, 73 were appraisable for efficacy and safety. In both treatment groups, papules and pustules were reduced significantly at the end of treatment (P < 0.001), and no statistical difference was observed between the groups. Comedones and microcysts were significantly improved with retinaldehyde combined with erythromycin (P = 0.005), but not with erythromycin alone. However, no statistical difference between the groups could be demonstrated (test power, 50%). Local tolerance of the combined treatment group was very satisfactory, as only a few patients experienced local irritation. In conclusion, retinaldehyde combined with erythromycin appears to be a valuable topical therapy in polymorphic acne.

[Diagnosis and evaluation of mitral endocarditis complicating obstructive cardiomyopathy using cardiac echo-Doppler]

The authors report a case of mitral endocarditis diagnosed by cardiac echo-Doppler and complicating an obstructive cardiomyopathy (OCM) in a 37-year-old woman. Despite the high degree of sub-aortic obstruction and the existence of an apparently severe mitral leak by Doppler analysis, the patient remained totally asymptomatic and the outcome was favourable with appropriate antibiotics. A review of the literature revealed 11 cases of endocarditis in a context of OCM, documented by echocardiography. Echo-Doppler enables precise evaluation of this grave and often poorly tolerated complication of OCM.

[Partial epilepsy in children in Algeria. Electroclinical and tomodensitometric study]

The authors report the results of an electroclinical and tomographic study of 145 cases of partial epilepsy in children. Without advancing any views on etiology or symptomatologic classification, they analyse the various prognoses on the basis of case history, clinical aspects, symptomatology of seizures, EEG and tomographic signs. None of these factors in isolation appears to determine the prognosis of epilepsy. A significant percentage of apparently idiopathic epilepsies may develop adversely whereas half of the cases show a good prognosis.