Involvement of CCL2 in Salivary Gland Response to Hyperosmolar Stress Related to Sjögren's Syndrome

In primary Sjögren's syndrome (pSS) patients, salivary gland (SG) epithelial cells (SGECs) could be exposed to chronic hyperosmotic stress (HOS), consecutive to their destruction and deregulation, that exacerbates an inflammatory response. The aims of this study were to assess the mechanism accounting for C-C motif chemokine ligand 2 (CCL2) expression in an immortalized human salivary gland epithelial acinar cell line (NS-SV-AC) subjected to HOS, as well as the involvement of CCL2 in pSS. CCL2 mRNA and protein levels were determined via RT-qPCR and ELISA. Reporter plasmids and a promoter pull-down assay were used to identify transcription factors associated with CCL2 mRNA increase. Our data showed that HOS-induced CCL2 mRNA increase was independent of the nuclear factor of activated T-cells 5 (NFAT5) and nuclear factor-kappa B (NFkB) but involved Kruppel-like factor 5 (KLF5). CCL2 protein levels, quantified by enzyme-linked immunosorbent assay (ELISA) in sera samples from pSS patients, correlated with the European Alliance of Associations for Rheumatology's Sjogren's syndrome disease activity index (ESSDAI) score for systemic activity. In addition, CCL2 protein levels were higher in patients with biological activity, cutaneous manifestations, and ESSDAI score superior or equal to five. Our data suggest that chronic HOS could exacerbate pSS disease by contributing to the inflammatory process induced by the expression and secretion of CCL2.

Intense Pulsed Light Therapy in the Treatment of Dry Eye Diseases: A Systematic Review and Meta-Analysis

BACKGROUND

Intense pulsed light therapy (IPL) is a recently developed way of treating dry eye disease (DED). During the last decade, there was a multiplication of trials studying IPL efficacy. The goal of this review is to summarize the most important and significant results of these trials estimating effect sizes.

METHODS

The PubMed and sciencedirect databases were searched using a PICO model-based approach. Randomized controlled trials including at least 20 patients with DED and no other eye condition, with a control group and break-up time or symptom scores data available for extraction were included in this review. Statistical analysis evaluated the tear break-up time (TBUT), non-invasive break-up time (NIBUT), ocular surface disease index (OSDI), and standard patient evaluation of eye dryness (SPEED). Three comparisons were carried on for each outcome: longest follow-up values vs. baseline in the treatment group, longest follow-up values in the treatment group vs. control group, and changes from baseline in the treatment group vs. control group. A subgroup analysis was carried on.

RESULTS

Eleven randomized controlled trials, published between 2015 and 2021 were included in this systematic review with 759 patients in total. The longest follow-up values vs. baseline in the treatment group analyses were significantly in favor of IPL for all the parameters studied for instance: NIBUT (effect size (ES), 2.02; 95% confidence interval (CI), (1.43; 2.62)), TBUT (ES, 1.83; 95% CI, (0.96; 2.69)), OSDI (ES, -1.38; 95% CI, (-2.12; -0.64)) and SPEED (ES, -1.15; 95% CI, (-1.72; -0.57)). The longest follow-up values in the treatment group vs. control group analyses, and, the change from baseline in the treatment group vs. control group analyses, were both significantly in favor of IPL for NIBUT, TBUT, and SPEED but not for OSDI.

CONCLUSIONS

IPL seems to have a positive effect on tear stability evaluated by the break-up times. However, the effect on DED symptoms is less clear. Some confounding factors such as the age and the IPL device used influence the results indicating that the ideal settings still need to be found and personalized for the patient.

Aquaporin-5 Dynamic Regulation

Aquaporin-5 (AQP5), belonging to the aquaporins (AQPs) family of transmembrane water channels, facilitates osmotically driven water flux across biological membranes and the movement of hydrogen peroxide and CO₂. Various mechanisms have been shown to dynamically regulate AQP5 expression, trafficking, and function. Besides fulfilling its primary water permeability function, AQP5 has been shown to regulate downstream effectors playing roles in various cellular processes. This review provides a comprehensive overview of the current knowledge of the upstream and downstream effectors of AQP5 to gain an in-depth understanding of the physiological and pathophysiological processes involving AQP5.

Impaired humoral immunogenicity of SARS-CoV-2 vaccination in rheumatoid arthritis patients

Humoral immunogenicity of SARS-CoV-2 vaccination in rheumatoid arthritis (RA) seem impaired depending on the underlying immunosuppressive agents, especially with rituximab, glucocorticoids and abatacept but data are still scarce (1–9). Identifying an impairment could lead to a treatment adaptation or a vaccine booster dose, to improve vaccine response.

Ezrin Is a Novel Protein Partner of Aquaporin-5 in Human Salivary Glands and Shows Altered Expression and Cellular Localization in Sjögren's Syndrome

Sjögren’s syndrome (SS) is an exocrinopathy characterized by the hypofunction of salivary glands (SGs). Aquaporin-5 (AQP5); a water channel involved in saliva formation; is aberrantly distributed in SS SG acini and contributes to glandular dysfunction. We aimed to investigate the role of ezrin in AQP5 mislocalization in SS SGs. The AQP5–ezrin interaction was assessed by immunoprecipitation and proteome analysis and by proximity ligation assay in immortalized human SG cells. We demonstrated, for the first time, an interaction between ezrin and AQP5. A model of the complex was derived by computer modeling and in silico docking; suggesting that AQP5 interacts with the ezrin FERM-domain via its C-terminus. The interaction was also investigated in human minor salivary gland (hMSG) acini from SS patients (SICCA-SS); showing that AQP5–ezrin complexes were absent or mislocalized to the basolateral side of SG acini rather than the apical region compared to controls (SICCA-NS). Furthermore, in SICCA-SS hMSG acinar cells, ezrin immunoreactivity was decreased at the acinar apical region and higher at basal or lateral regions, accounting for altered AQP5–ezrin co-localization. Our data reveal that AQP5–ezrin interactions in human SGs could be involved in the regulation of AQP5 trafficking and may contribute to AQP5-altered localization in SS patients

Current State of Knowledge on Primary Sjögren's Syndrome, an Autoimmune Exocrinopathy

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune rheumatic disease characterized by lymphoplasmacytic infiltration of the salivary and lacrimal glands, whereby sicca syndrome and/or systemic manifestations are the clinical hallmarks, associated with a particular autoantibody profile. pSS is the most frequent connective tissue disease after rheumatoid arthritis, affecting 0.3-3% of the population. Women are more prone to develop pSS than men, with a sex ratio of 9:1. Considered in the past as innocent collateral passive victims of autoimmunity, the epithelial cells of the salivary glands are now known to play an active role in the pathogenesis of the disease. The aetiology of the "autoimmune epithelitis" still remains unknown, but certainly involves genetic, environmental and hormonal factors. Later during the disease evolution, the subsequent chronic activation of B cells can lead to the development of systemic manifestations or non-Hodgkin's lymphoma. The aim of the present comprehensive review is to provide the current state of knowledge on pSS. The review addresses the clinical manifestations and complications of the disease, the diagnostic workup, the pathogenic mechanisms and the therapeutic approaches.

Dermatomyositis Associated with Sarcoidosis: Two Cases

Dermatomyositis (DM) and sarcoidosis are two idiopathic systemic disorders. Reports of patients with both conditions are extremely rare. Here we describe two patients who presented with DM and DM-associated antibodies, and later developed biopsy-proven sarcoidosis. There are increasing reports of the occurrence of sarcoidosis in the context of autoimmune diseases. These observations might imply similarities in the pathogenetic mechanisms.

[The new classification criteria for spondylarthritis: implications in clinical practice]

" Spondyloarthritis" consists of a group of several diseases sharing clinical, radiological and genetic similarities. Ankylosing spondylitis is the main representative of this group and is characterized by a predominant axial involvement. The presence of radiographic sacroiliitis is essential for the diagnosis of ankylosing spondylitis according to the modified New York criteria. Because the occurence of radiographic sacroiliitis takes 8 to 11 years, the diagnosis of spondyloarthritis is often delayed. Magnetic resonance imaging can depict sacroiliac joint inflammation before the appearance of radiographic damage thereby defining the concept of " non-radiographic axial spondylo-arthritis". This entity was defined by the axial spondyloarthritis classification criteria published by the Assessment of SpondyloArthritis international Society (ASAS). Some factors, such as elevated levels of C-reactive protein at baseline, have been identified as predictors of radiographic sacroiliitis progression, leading to a definite diagnosis of ankylosing spondylitis. These two entities show similar clinical expression (clinical features and activity levels), suggesting continuity between the two diseases. Non-radiographic forms most often affect women and patients with recent symptoms, and are therefore considered as a pre-radiographic status. If the use of magnetic resonance imaging is necessary for the identification of non-radiographic axial spondyloarthritis according to the ASAS criteria, the presumptive diagnosis is mainly based on complaints of inflammatory back pain. The presence of other typical clinical features, such as HLA B27 positivity and/or radiographic sacroiliitis increases the diagnostic probability and indicates the need for referral to a specialist.

Non-malignant causes of hypercalcemia in cancer patients: a frequent and neglected occurrence

PURPOSE

Hypercalcemia is a frequent finding in cancer patients and can be observed in any type of cancer. The physician in charge of cancer patients often ignores non-malignant causes of hypercalcemia. Our objective was to review the causes of hypercalcemia in a large series of cancer patients.

METHODS

We have retrospectively studied in a Cancer Centre all consecutive hypercalcemic (Ca> 10.5 mg/dl) patients over an 8-year period. Of 699 evaluated patients, 642 were analyzed after exclusion of patients whose hypercalcemia resolved after rehydration or who had a normal Ca level after correction for protein concentrations. Clinical information was gathered on the type of cancer, its histology, whether the disease was active or in complete remission, and on the presence of bone metastases. Biochemical data included serum Ca, P(i), proteins in all patients, PTH in most patients, and PTHrP, 25OH-Vitamin D, 1,25(OH)(2)-Vitamin D, TSH, and T4 in selected cases.

RESULTS

By order of decreasing frequency, the main causes of hypercalcemia were cancer (69.0 %), primary hyperparathyroidism (24.6 %), hyperthyroidism (2.2 %), milk alkali syndrome (0.9 %), and sarcoidosis (0.45 %). In cancer-related causes, bone metastases accounted for 53.0 % of the cases, humoral hypercalcemia of malignancy (HHM) for 35.3 % while there were 11.7 % of cases apparently due to both HHM and bone metastases. Hypercalcemia was not due to cancer in 97 % (84/87) of the patients who were in complete remission. Even in patients with active neoplastic disease, the number of patients whose hypercalcemia was not due to cancer remained clinically relevant (115/555 = 20.5 %). In the 158 patients with primary hyperparathyroidism, 92 patients were in complete remission and 66 patients had active neoplastic disease.

CONCLUSIONS

In this large series of hypercalcemia in cancer patients, the cause was not due to cancer in almost one third of the cases. Most patients considered to be in complete remission had hypercalcemia due to a benign condition. In that perspective, serum PTH determination is essential in the approach of hypercalcemic cancer patients since primary hyperparathyroidism is by far the first non-malignant cause of hypercalcemia.

Relationship between aquaporin-5 expression and saliva flow in streptozotocin-induced diabetic mice?

OBJECTIVE

To investigate the expression and distribution of AQP5 in submandibular acinar cells from sham- and streptozotocin (STZ)-treated mice in relation to the salivary flow.

METHODS

Mice were sham or STZ injected. Distribution of AQP5 subcellular expression in submandibular glands was determined by immunohistochemistry. AQP5 labelling indices (LI), reflecting AQP5 subcellular distribution, were determined in acinar cells. Western blotting was performed to determine the expression of AQP5 in submandibular glands. Blood glycaemia and osmolality and saliva flow rates were also determined.

RESULTS

AQP5 immunoreactivity was primarily located at the apical and apical-basolateral membranes of submandibular gland acinar cells from sham- and STZ-treated mice. No significant differences in AQP5 protein levels were observed between sham- and STZ-treated mice. Compared to sham-treated mice, STZ-treated mice had significant increased glycaemia, while no significant differences in blood osmolality were observed. Saliva flow rate was significantly decreased in STZ-treated mice as compared to sham-treated mice.

CONCLUSIONS

In STZ-treated mice, significant reduction in salivary flow rate was observed without any concomitant modification in AQP5 expression and localization.

Link between inflammation and aquaporin-5 distribution in submandibular gland in Sjögren's syndrome?

OBJECTIVE

To determine whether a link exists between inflammation and aquaporin-5 distribution in submandibular glands from three animal models for Sjögren's syndrome: IQI/JIC, r1ΔT/r2n and non-obese diabetic mice.

METHODS

Mice of different ages were used. Inflammatory infiltrates were quantified using the focus score. Acinar aquaporin-5 subcellular distribution was determined by immunohistochemistry and quantified using labelling indices.

RESULTS

  Minor inflammatory infiltrates were present in r1f/r2n mice. Massive inflammatory infiltrates and acinar destruction were observed in 24-week-old non-obese diabetic mice, 10-and 13-month-old IQI/JIC mice and some r1ΔT/r2n mice. Aquaporin-5 immunoreactivity was primarily apical in submandibular glands from 8- and 24-week-old Balb/C mice, 8-week-old non-obese diabetic mice, 2-, 4- and 7-month-old IQI/JIC mice and r1f/r2n mice. In contrast, decreased apical aquaporin-5 labelling index with concomitant increased apical-basolateral, apical-cytoplasmic and/or apical-basolateral-cytoplasmic aquaporin-5 labelling indices was observed in 24-week-old non-obese diabetic, 10- and 13-month-old IQI/JIC and r1ΔT/r2n mice with a focus score≥1.

CONCLUSIONS

  Altered aquaporin-5 distribution in submandibular acinar cells from IQI/JIC, non-obese diabetic and r1ΔT/r2n mice with a focus score≥1 appears to be concomitant to the presence of inflammatory infiltrates and acinar destruction.

Aquaporin-4 overexpression in rat ALS model

Onset of motoneuron death characterizing amyotrophic lateral sclerosis (ALS) is closely linked to modified astrocytic and glial environments. Here, we show that in the spinal cord from transgenic rat overexpressing mutated human SOD1, aquaporin-4 mRNA and protein are specifically overexpressed in the gray matter at end stage of disease. Immunohistochemistry and double immunofluorescence allowed to detect, in the spinal cord gray matter of the ALS rat, increased aquaporin-4 surrounding both vessel and motoneuron perikarya. The use of pre-embedding immunohistochemistry at electron microscopic level confirmed such localization associated with swollen astrocytic processes surrounding the vessels. The AQP4 immunohistochemical labeling surrounding several motoneuron perikarya was only seen in ALS rats. Identification of this AQP4-positive cellular type remains unclear.

Usefulness of mouse models to study the pathogenesis of Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disorder characterized by ocular and oral dryness as well as systemic manifestations. The immunopathogenesis of SS is complex with different intricate factors. Because of the delay in the appearance of symptoms and due to ethical issues it is very difficult to study the wide array of factors intervening in the pathogenesis of SS in human patients. To circumvent this problem, different animal models have been elaborated for studying the different subsets of the aspects of the physiopathology of this disease. In this review, we focus on the mouse models that have been established to deepen our insight into the immunopathogenesis of SS.