Plasma pentraxin 3 in idiopathic inflammatory myopathies: a possible new biomarker of disease activity

Pentraxin-3 (PTX3) is a component of humoral innate immunity with essential functions both in promotion and resolution of inflammation. We aimed to study the PTX3 in the plasma and in the muscle of patients with idiopathic inflammatory myopathies (IIM) and whether PTX3 may correlate with disease activity. Plasma PTX3 levels were assessed in 20 patients with IIMs, 10 dermatomyositis (DM), and 10 polymyositis (PM), compared to 10 patients with rheumatoid arthritis (RA) and 10 healthy donors (HDs) aged, sex, and body mass index matched. Disease activity in IIMs was assessed by Myositis Disease Activity Assessment Visual Analog Scale (MYOACT), while disease activity score on 28 joints (DAS28) was used for RA patients. Muscle histopathology and immunohistochemical (IHC) analyses were also performed. Mean plasma PTX3 levels were significantly higher in IIM patients than HDs (518 ± 260 pg/ml vs. 275 ± 114 pg/ml, P = 0.009). Linear regression analysis adjusted for age, sex, and disease duration showed a direct correlation between PTX3 and CPK levels (β: 0.590), MYOACT (β: 0.759), and physician global assessment of disease activity (β: 0.832) in IIMs. No association between PTX3 levels and DAS28 was found in RA. Global PTX3 pixel fraction was higher in IIM than HDs muscle, but a lower PTX3 expression was found in perifascicular areas of DM and in myofibers with sarcolemmal staining for membrane attack complement. PTX3 plasma levels were increased in IIMs and correlated with disease activity suggesting a possible role as biomarker of disease activity. PTX3 showed a different distribution in DM or PM muscle.

THU0344 CLINICAL AND HISTOLOGICAL SPECTRUM OF ANTI-MI2 DERMATOMYOSITIS: A MULTICENTRE RETROSPECTIVE COHORT

Background:

Dermatomyositis (DM) shows a wide clinical spectrum that seems to be different based on the type of autoantibody status. Furthermore, less is known regarding to the histopathology of different serological subsets of DM

Objectives:

The aim of our study was to investigate clinical and histopathological hallmarks in adult DM patients positive for anti-Mi2 (Mi2+) antibody compared to DM patients negative for anti-Mi2 (Mi2-)

Methods:

All clinical data of adult DM patients admitted in three tertiary Rheumatology Units, who fulfilled EULAR/ACR 2017 classification criteria1, were included in this study. Overlap syndrome and antisynthetase syndrome were exclusion criterion. Serum samples were tested in the local reference laboratories using line immunoassays methods for Myositis specific and associated antibodies. Histopathological study was carried out from muscle biopsies performed for diagnostic purpose in outpatient clinic of Bari (Italy) University. Quantitative analysis was performed for myofiber and capillary features, whereas semi-quantitative analysis (score from 0 to 3) was performed for inflammatory cells infiltrate, both at endomysial and perimysial sites

Results:

A total of 95 DM patients, followed for a median (IQR) follow-up of 28 (9-85) months, were analyzed. Of these, 23 (24.2%) patients (87% female, mean age at onset 55.4±16.2 years) were anti-Mi2+, while 72 (75.8%) patients were Mi2- (72.2% female, mean age at onset 55.2±17 years). All Mi2+ patients showed muscle involvement. Moreover, Mi2+ DM showed higher levels of serum creatine kinase (CK) at onset compared to Mi2- (CK (IQR): 2649 UI/l (1130-6000) vs 575 UI/l (164-1617), p<0.001). Prevalence of interstitial lung disease (ILD) was lower in Mi2+ patients (8.7% vs 30.6%, p=0.05), and no case of rapidly progressive ILD (RP-ILD) was found. Survival analysis at 5-years follow-up highlighted good survival for Mi2+ patients, but not different from Mi2- (95.7% vs 83.1%, p=0.151). Multivariate analysis showed that age at onset (HR:1.07), RP-ILD (HR:36.2) and cancer associated myositis (HR:6.1) correlated with a poor prognosis. Finally, a total of 26 biopsies (12 Mi2+ and 14 Mi2-) were included into the histological analysis showing higher prevalence of necrotic/degenerating myofibers (median (IQR) 2.6 (0.7-11)% vs 0.6 (0.4-1.1)%, p=0.009) and sarcoplasmic deposit of membrane attack complex (MAC) (median (IQR) 0.2 (0-1.2)% vs (0(0-0)%,p=0.009) in Mi2+ patients. In addition, the endomysial macrophage score was higher in Mi-2+ patients (median 1.5 (0.25-2) vs (0.5 (0-1), p=0.031)

Conclusion:

Mi2+ patients represent a specific DM subset with higher muscle damage, sarcoplasmic MAC deposits and endomysial macrophages infiltration as histological hallmarks

References:

[1]Ann Rheum Dis. 2017 Dec;76(12):1955-1964

Disclosure of Interests:

Marco Fornaro: None declared, Francesco Girolamo: None declared, Lorenzo Cavagna: None declared, Franco Franceschini: None declared, margherita giannini: None declared, Giovanni Zanframundo: None declared, Micaela Fredi: None declared, Marilin Tampoia: None declared, Angela Amati: None declared, Luigi Serlenga: None declared, Anna Lia: None declared, Liala Moschetti: None declared, Dario Dabbicco: None declared, Laura Coladonato: None declared, Florenzo Iannone Consultant of: Speaker and consulting fees from AbbVie, Eli Lilly, Novartis, Pfizer, Roche, Sanofi, UCB, MSD, Speakers bureau: Speaker and consulting fees from AbbVie, Eli Lilly, Novartis, Pfizer, Roche, Sanofi, UCB, MSD

Overexpression of autophagic proteins in the skeletal muscle of sporadic inclusion body myositis

AIMS

Sporadic inclusion body myositis (s-IBM) is characterized by rimmed vacuole formation and misfolded protein accumulation. Intracellular protein aggregates are cleared by autophagy. When autophagy is blocked aggregates accumulate, resulting in abnormal rimmed vacuole formation. This study investigated the autophagy-lysosome pathway contribution to rimmed vacuole accumulation.

METHODS

Autophagy was studied in muscle biopsy specimens obtained from eleven s-IBM patients, one suspected hereditary IBM patient, nine patients with other inflammatory myopathies and nine non-myopathic patients as controls. The analysis employed morphometric methods applied to immunohistochemistry using the endosome marker Clathrin, essential proteins of the autophagic cascade such as AuTophaGy-related protein ATG5, splicing variants of microtubule-associated protein light chain 3a (LC3a) and LC3b, compared with Beclin 1, the major autophagy regulator of both the initiation phase and late endosome/lysosome fusion of the autophagy-lysosome pathway.

RESULTS

In muscle biopsies of s-IBM patients, an increased expression of Clathrin, ATG5, LC3a, LC3b and Beclin 1 was shown. Moreover, the inflammatory components of the disease, essentially lymphocytes, were preferentially distributed around the Beclin 1(+) myofibres. These affected myofibres also showed a moderate sarcoplasmic accumulation of SMI-31(+) phospho-tau paired helical filaments.

CONCLUSION

The overexpression of autophagy markers linked to the decreased clearance of misfolded proteins, including SMI-31, and rimmed vacuoles accumulation may exhaust cellular resources and lead to cell death.

Regenerative surgery performed with platelet-rich plasma used in sinus lift elevation before dental implant surgery: an useful aid in healing and regeneration of bone tissue

OBJECTIVES

Aim of this work is to show the effectiveness of a protocol involving the use of platelet-rich plasma (PRP) as a grafting material in bone regeneration before dental implant rehabilitation.

MATERIALS AND METHODS

127 patients, requiring maxillary sinus lift, were enrolled in a follow-up study plan, which established clinical and radiological examinations on the day after surgery and six months later. PRP, in combination with autogenous bone, an organic bone material and organic bone substitutes, was used before implant-prosthetic rehabilitation.

RESULTS AND CONCLUSIONS

After implant placement, 63 patients, previously treated with PRP, reached a statistically significant improvement in implant-prosthetic rehabilitation, established by primary stability and radiographic integration criteria, in comparison with the other 64 patients receiving implant-prosthetic rehabilitation without PRP treatment.

Effects of prenatal exposure to the CB-1 receptor agonist WIN 55212-2 or CO on the GABAergic neuronal systems of rat cerebellar cortex

The aim of this study was to assess the effects of prenatal exposures to cannabinoids or carbon monoxide (CO) in an animal experimental model reproducing the environmental conditions in which a fetus develops whose mother, during pregnancy, ingests by smoking low doses of cannabinoids or CO. Particular attention was devoted to analyses of the long-term effects of the exposures at the level of the cerebellar cortex, where already during prenatal development the GABAergic neuronal systems may be modulated by both cannabinoids and CO. Three groups of rats were subjected to the following experimental conditions: exposure to cannabinoids by maternal treatment during pregnancy with the cannabinoid CB-1 receptor agonist WIN 55212-2 (WIN) (0.5 mg/kg/day, s.c.); exposure to CO by maternal exposure during pregnancy to CO (75 parts per million, by inhalation); and exposure to WIN+CO at the above doses and means of administration; a fourth group was used as control. The body weight of dams, length of pregnancy, litter size at birth, body weight and postnatal mortality of pups were monitored in order to evaluate possible effects of the exposures on reproduction and on prenatal and postnatal development. In the different groups, the long-term effects of the exposures were studied in adult rats (120-150 days) by light microscopy analyses of the structure of the cerebellar cortex and of the distribution in the cortex of markers of GABAergic neurons, such as GAD and GABA itself. Results. Exposures to WIN or CO did not affect reproduction or prenatal/postnatal development. Moreover, the exposed rats showed no structural alterations of the cerebellar cortex and displayed qualitative distribution patterns of GAD and GABA immunoreactivities similar to those of the controls. However, quantitative analyses indicated significant changes of both of these immunoreactivities: in comparison with the controls, they were significantly increased in WIN-exposed rats and reduced in CO-exposed rats, but not significantly different in WIN+CO-exposed rats. The changes were detected in the molecular and Purkinje neuron layers, but not in the granular layer. Prenatal exposures of rats to WIN or CO, at doses that do not affect reproduction, general processes of development and histomorphogenesis of the cerebellar cortex, cause significant changes of GAD and GABA immunoreactivities in some GABAergic neuronal systems of the adult rat cerebellar cortex, indicating selective up-regulation of GABA-mediated neurotransmission as a long-term consequence of chronic prenatal exposures to cannabinoids or CO. Because the changes consist of overexpression or, vice versa, underexpression of these immunoreactivities, functional alterations of opposite types in the GABAergic systems of the cerebellum following exposure to WIN or CO can be postulated, in agreement with the results of behavioral and clinical studies. No changes in immunoreactivities were detected after prenatal exposure to WIN and CO in association.

Non-traditional large neurons in the granular layer of the cerebellar cortex

The granular layer of the cerebellar cortex is composed of two groups of neurons, the granule neurons and the so-called large neurons. These latter include the neuron of Golgi and a number of other, lesser known neuron types, generically indicated as non-traditional large neurons. In the last few years, owing to the development of improved histological and histochemical techniques for studying morphological and chemical features of these neurons, some non-traditional large neurons have been morphologically well characterized, namely the neuron of Lugaro, the synarmotic neuron, the unipolar brush neuron, the candelabrum neuron and the perivascular neuron. Some types of non-traditional large neurons may be involved in the modulation of cortical intrinsic circuits, establishing connections among neurons distributed throughout the cortex, and acting as inhibitory interneurons (i.e., Lugaro and candelabrum neurons) or as excitatory ones (i.e., unipolar brush neuron). On the other hand, the synarmotic neuron could be involved in extrinsic circuits, projecting to deep cerebellar nuclei or to another cortex regions in the same or in a different folium. Finally, the perivascular neuron may intervene in the intrinsic regulation of the cortex microcirculation.

Glutamic acid decarboxylase and GABA immunoreactivities in the cerebellar cortex of adult rat after prenatal exposure to a low concentration of carbon monoxide

Glutamic acid decarboxylase and GABA immunoreactivities were qualitatively and quantitatively evaluated in the cerebellar cortex of adult rats prenatally exposed to a low concentration of carbon monoxide (75 parts per million). Carbon monoxide-exposed and control rats were perfused with modified Bouin's fluid and their cerebella were embedded in paraffin. Sections from the vermis of each cerebellum were stained with Toluidine Blue or assayed with anti-glutamic acid decarboxylase 65/67 or with anti-GABA antisera. In the Toluidine Blue-stained sections, no differences were observed in the microscopic structure of the cerebellar cortex between carbon monoxide-exposed rats and controls. The distribution patterns of glutamic acid decarboxylase and GABA immunoreactivities in the cerebellar cortex of the treated animals were qualitatively comparable to those of the controls, and in accordance with previous descriptions of glutamic acid decarboxylase and GABA immunoreactivities in the rat cerebellar cortex. However, quantitative analyses demonstrated a significant reduction of immunoreactivities to both substances in the exposed rats in comparison with the controls. The reduction regarded: in the molecular layer, the number of glutamic acid decarboxylase/GABA-immunoreactive neuronal bodies and of axon terminals and the area they covered; in the Purkinje neuron layer, the number and the area covered by glutamic acid decarboxylase/GABA immunoreactive axon terminals. The differences detected in the prenatally exposed adult rats could be due to carbon monoxide-induced impairment of the differentiation of cerebellar GABA synthesizing neurons. A consequently diminished synthesis of GABA might account for some behavioral disorders detected in adult rats submitted to the same experimental procedure.

Effects of methylmercury on the microvasculature of the developing brain

The study, undertaken with the aim of further investigating the effects of methylmercury (MeHg) exposure on the developing brain, was performed in the cerebellum of chick embryos, chronically treated with a MeHgCl solution dropped onto the chorioallantoic membrane, and in control embryo cerebella. Quantitative evaluations, performed by cold vapour atomic absorption spectrophotometry, demonstrated a high mercury content in the chorioallantoic membrane, encephalon, liver and kidney of the treated embryos. The morphological observations showed severe neuronal damage consisting of degenerative changes of the granules and Purkinje neurons. The effects on astrocytes were even more severe, since they were extremely rare both in the neuropil and around the vessel wall. Compared with the controls, the cerebellar vessels of MeHg-treated embryos showed immature morphology, poor differentiation of endothelial barrier devices, and high permeability to the exogenous protein horseradish peroxidase. These findings support the hypothesis that MeHg-related neuronal sufferance may be secondary to astrocytic damage and suggest that the developmental neurotoxicity of this compound could also be related to astrocyte loss-dependent impairment of blood-brain barrier (BBB) differentiation.

Choline acetyltransferase-containing neurons in the human parietal neocortex

A number of immunocytochemical studies have indicated the presence of cholinergic neurons in the cerebral cortex of various species of mammals. Whether such cholinergic neurons in the human cerebral cortex are exclusively of subcortical origin is still debated. In this immunocytochemical study, the existence of cortical cholinergic neurons was investigated on surgical samples of human parietal association neocortex using a highly specific monoclonal antibody against choline acetyltransferase (ChAT), the acetylcholine biosynthesising enzyme. ChAT immunoreactivity was detected in a subpopulation of neurons located in layers II and III. These were small or medium-sized pyramidal neurons which showed cytoplasmic immunoreactivity in the perikarya and processes, often in close association to blood microvessels. This study, providing demonstration of ChAT neurons in the human parietal neocortex, strongly supports the existence of intrinsic cholinergic innervation of the human neocortex. It is likely that these neurons contribute to the cholinergic innervation of the intracortical microvessels.

Glutamic acid decarboxylase immunoreactive large neuron types in the granular layer of the human cerebellar cortex

'Non-traditional' large neurons of the granular layer of the cerebellar cortex include all its large neuronal types, except the Golgi neuron, which is instead one of the five 'classic' types of corticocerebellar neurons. The morphological, chemical and functional characteristics of the 'non-traditional' large neurons have not been entirely ascertained. The aim of this study was to ascertain whether morphological evidence can be provided of GABA synthesis within the 'non-traditional' large neurons of the human cerebellar cortex by means of immunocytochemistry for glutamic acid decarboxylase (GAD). Fragments of postmortem cerebellar cortex of various lobules from the hemispheres and vermis were studied. Immunoreactions revealed large neurons distributed throughout the granular layer in all lobules examined. They were discriminated by analyzing the morphological features of their bodies and processes and were identified as Golgi neurons and as some 'non-traditional' types, such as the candelabrum, Lugaro and synarmotic neurons. In addition, immunoreactive large neurons, with their bodies and processes closely adjacent to microvessels, were observed throughout the layer: these perivascular neurons could represent a new type of 'non-traditional' neuron of the cerebellar cortex. This study supplies the first indication that in the human cerebellar cortex some types of 'non-traditional' large neurons are GAD-immunoreactive, in addition to those neurons already known to be GABAergic (i.e., stellate, basket, Purkinje and Golgi neurons). These morphological data further point out possible functional roles for GABA as a neurotransmitter/neuromodulator in intrinsic, associative and projective circuits of the cerebellar cortex.

GABA immunoreactivity in the human cerebellar cortex: a light and electron microscopical study

The distribution of gamma-aminobutyric acid (GABA) in surgical samples of human cerebellar cortex was studied by light and electron microscope immunocytochemistry using a polyclonal antibody generated in rabbit against GABA coupled to bovine serum albumin with glutaraldehyde. Observations by light microscopy revealed immunostained neuronal bodies and processes as well as axon terminals in all layers of the cerebellar cortex. Perikarya of stellate, basket and Golgi neurons showed evident GABA immunoreactivity. In contrast, perikarya of Purkinje neurons appeared to be negative or weakly positive. Immunoreactive tracts of longitudinally- or obliquely-sectioned neuronal processes and punctate elements, corresponding to axon terminals or cross-sectioned neuronal processes, showed a layer-specific pattern of distribution and were seen on the surface of neuronal bodies, in the neuropil and at microvessel walls. Electron microscope observations mainly focussed on the analysis of GABA-labelled axon terminals and of their relationships with neurons and microvessels. GABA-labelled terminals contained gold particles associated with pleomorphic vesicles and mitochondria and established symmetric synapses with neuronal bodies and dendrites in all cortex layers. GABA-labelled terminals associated with capillaries were seen to contact the perivascular glial processes, basal lamina and endothelial cells and to establish synapses with subendothelial unlabelled axons.

Developmental effects of lead acetate on the chick embryo metanephros

The developmental effects of lead acetate were studied in the chick embryo metanephros, the third renal rudiment that acquires morphological characteristics of functioning kidney already during the prenatal life. Lead exposure was obtained by applying a lead acetate solution on the chick embryo chorioallantoic membrane at the days 9, 10 and 11 of incubation. Quantitative evaluation of the lead concentration assessed by furnace atomic absorption spectrophotometry at the days 14 and 21 of incubation demonstrated metal presence both in the chorioallantoic membrane (CAM) and in metanephros (MN). The lead concentration was higher in CAM than in MN; the metal amount was similar in the CAM of 14 and 21 day embryos, but significantly higher in the 14day embryo MN than in the 21 day embryo MN. Morphological observations on metanephros tissue of control and lead-treated embryos were performed under light, electron transmission and electron scanning microscopes. Peculiar attention was devoted to the expression of the junctional protein connexin 43, the major component of the gap junctions in the renal cells. The results indicated that lead treatment does not intervene in the general differentiation of the metanephric nephrons. The lead is reabsorbed by the proximal tubule cells that are engulfed by endocytotic vacuoles and metal deposits and show long term degenerative changes. Expression of Cx43 protein and ultrastructure of gap junctions between proximal tubule cells appeared to be unchanged. The morphological aspects of the MN corpuscles and tubules agree with the suggestion of a lead cytotoxic effect but do not corroborate, at least in this experimental model, the view of primary damage exerted by lead on the gap junctions of the renal epithelial cells.