Undiagnosed connective tissue diseases: High prevalence in pulmonary arterial hypertension patients

Umbilical Cord Mesenchymal Stem Cells for Inhibiting the Fibrosis and Autoimmune Development in HOCl-Induced Systemic Scleroderma Mouse Model

Background and Objectives

Systemic scleroderma (SSc) is a rare and serious connective tissue disease, an autoimmune disease, and a rare refractory disease. In this study, preventive effect of single systemic human umbilical cord mesenchymal stem cells (UC-MSCs) transfusion on SSc was preliminarily explored.

Methods and Results

SSc mouse model was established by daily intradermal injection of Hypochlorite (HOCl). SSc mice were treated by single transfusion of UC-MSCs at 0.625×10⁵, 2.5×10⁵ and 1×10⁶ respectively. At the 42nd day of intradermal injection of HOCl, the symptoms showed up by skin and alveolar wall thickening, lymphocytic infiltration, increased collagen in skin/lung, and the increased proportion of CD3^＋CD4^＋CD25^＋FoxP3^＋ cells (a Treg subset) in spleen. After UC-MSCs transfusion, the degree of skin thickening, alveolar wall thickening and lymphocyte infiltration were decreased, the collagen sedimentation in skin/lung was decreased, and the proportion of CD3^＋CD4^＋CD25^＋FoxP3^＋ cells was decreased.

Conclusions

UC-MSC can achieve a preventive effect in SSc mice by fibrosis attenuation and immunoregulation.

Inflammatory Mechanisms in the Pathogenesis of Pulmonary Arterial Hypertension: Recent Advances

Inflammatory processes are increasingly recognized in the pathogenesis of the vascular remodeling that characterizes pulmonary arterial hypertension (PAH). Chronic inflammation may contribute to disease progression or serve as a biomarker of PAH severity. Furthermore, inflammatory pathways may represent possible therapeutic targets for novel PAH-specific drugs beyond the currently approved therapies targeting the endothelin, nitric oxide/cyclic GMP, and prostacyclin biological pathways. The main focus of this article is to provide recent advances in the understanding of the role of inflammatory pathways in the pathogenesis of PAH from preclinical studies and current clinical data supporting chronic inflammation in PAH patients and to discuss emerging therapeutic implications. © 2021 American Physiological Society. Compr Physiol 11:1805-1829, 2021.

Systemic Sclerosis and Pulmonary Disease

Systemic sclerosis is a complex, often progressive, multisystem autoimmune disease. It is commonly categorized into limited cutaneous or diffuse cutaneous systemic sclerosis. There is near universal involvement of skin fibrosis and gastrointestinal dysfunction, but lung disease is not only common but also a most serious complication. Severe lung disease is the top cause of mortality, displacing scleroderma renal crisis as the leading cause of death. Whether there is limited cutaneous or diffuse cutaneous manifestations can be predictive of what type of lung disease that can present in the patient. Limited cutaneous systemic sclerosis patients tend to have pulmonary hypertension whereas diffuse cutaneous systemic sclerosis patients tend to have interstitial lung disease. There are more rare phenotypes associated with antibodies Th/To and U3RNP that can have both pulmonary hypertension and interstitial lung disease concomitantly. There are inherent challenges in the management for both pulmonary hypertension and interstitial lung disease but with the focus on early diagnosis for each of these lung complications, treatment may have a higher chance of efficacy.

Morphological signs of connective tissue dysplasia as predictors of frequent post-exercise musculoskeletal disorders

Background

Connective tissue dysplasia (CTD) is a risk factor for musculoskeletal disorders. Changes caused by disorganization of collagen and elastin fibers lead to the inability of withstanding heavy mechanical stress. In clinical practice, diagnosis of these disorders depends on physical and anthropomorphic evaluation.

Methods

Forty-eight patients with frequent post-exercise musculoskeletal disorders were evaluated for CTD. The control group included 36 healthy participants. Both groups were evaluated via therapeutic examination with assessment of anthropometric indicators and physical-physiological evaluation, surveying and gathering of anamnesis. Based on testing results, study participants were evaluated on CTD presence and risk factors.

Results

All experimental group patients had connective tissue dysplasia of moderate and severe degree, with a total score of 49.44 ± 13.1. Certain morphological characteristics showed prevalence, allowing to determine pathognomonic predictors of high predisposition to frequent post-exercise musculoskeletal disorders. Back pain (100%), asthenic syndrome and kyphotic spinal deformation (75%), high gothic palate, hypermobility of joints and the auricles, excessive elasticity (63%), varicose veins of the lower extremities (56%) and hemorrhoids (56%), changes in the shape of the legs and temporomandibular joint (50%) showed to be significant clinical factors indicating possible connective tissue dysplasia.

Conclusions

The presence of these diagnostically significant morphological signs of CTD in humans is a pathognomonic predictor of a high predisposition to frequent injuries. Their early detection helps promote proper appointment of adequate physical activity regimen and develop treatment for the underlying cause.

Multidisciplinary Approach in the Early Detection of Undiagnosed Connective Tissue Diseases in Patients With Interstitial Lung Disease: A Retrospective Cohort Study

Interstitial lung disease (ILD) encompasses a wide range of parenchymal lung pathologies with different clinical, histological, radiological, and serological features. Follow-up, treatment, and prognosis are strongly influenced by the underlying pathogenesis. Considering that an ILD may complicate the course of any connective tissue disease (CTD) and that CTD's signs are not always easily identifiable, it could be useful to screen every ILD patient for a possible CTD. The recent definition of interstitial pneumonia with autoimmune features is a further confirmation of the close relationship between CTD and ILD. In this context, the multidisciplinary approach is assuming a growing and accepted role in the correct diagnosis and follow-up, to as early as possible define the best therapeutic strategy. However, despite clinical advantages, until now, the pathways of the multidisciplinary approach in ILD patients are largely heterogeneous across different centers and the best strategy to apply is still to be established and validated. Aims of this article are to describe the organization of our multidisciplinary group for ILD, which is mainly focused on the early identification and management of CTD in patients with ILD and to show our results in a 1 year period of observation. We found that 15% of patients referred for ILD had an underlying CTD, 33% had interstitial pneumonia with autoimmune feature, and 52% had ILD without detectable CTD. Furthermore, we demonstrated that the adoption of a standardized strategy consisting of a screening questionnaire, specific laboratory tests, and nailfold videocapillaroscopy in all incident ILD proved useful in making the right diagnosis.

Interstitial pneumonia with autoimmune features: a new classification still on the move

In the past decade, the attention has been focused on the relationship between interstitial lung disease (ILD) and connective tissue diseases (CTDs). The clinical impact, as well as the therapeutic approach, classification and diagnosis have been addressed. These two latter items represent an area of great interest because the underlying conditions leading to ILD and the most appropriate treatment still needs to be defined. Recently, the European Respiratory Society/American Thoracic Society proposed the interstitial pneumonia with autoimmune features (IPAF) criteria which represents the effort of pulmonologists to classify patients that may remain clinically undefined [1]. The analysis of these criteria shows that IPAF, similarly to pulmonary arterial hypertension classification [2], may cluster conditions referring to a wide spectrum of rheumatic conditions such as systemic sclerosis, myositis, rheumatoid arthritis and overlap syndromes. These diseases are characterised by highly different characteristics, evolution and therapeutic approaches. Furthermore, IPAF criteria have an intrinsically changing structure, related to the regular update of existing CTD classification criteria and to the even more common identification of new biomarkers in CTDs. By far the most important effect of these criteria is the identification of a grey zone of not well-defined rheumatology conditions, e.g. anti-synthetase syndrome (ASSD) [3]. In this issue of the European Respiratory Review, Sambataroet al. [4] address the need to identify specific clinical characteristics and potential areas of improvement in IPAF patients. The starting point of the review is interesting because of the exclusion of papers that included patients diagnosed with ASSD, because no ASSD established classification criteria still exist. The authors' choice is related to the unique characteristics of ASSD, in which it is not unusual to observe the occurrence during follow-up of findings lacking at disease onset. [5]. However, as reported previously [6], in the case of anti-synthetase antibody positivity, the diagnostic scenario may vary with the same patient diagnosed with ASSD if referred to a rheumatologist, or IPAF if referred to a pulmonologist. In fact, a high prevalence of anti-synthetase antibody positivity is reported in the majority of papers evaluated by Sambataroet al. [4], thus confirming the fact that despite the presence of this antibody (identifying ASSD) patients may frequently end up being classified as having IPAF. However, some IPAF patients could not be tested for the entire spectrum of antibodies, probably due to the local unavailability of these tests, or because initial anti-Ro antibody positivity might have prompted the clinicians to evaluate further non-anti-Jo-1 myositis specific auto-antibodies. In fact, it is established that anti-Ro antibodies and anti-synthetase antibodies may co-occur in about 50% of cases, even when patients could be classified as IPAF [7]. Furthermore, we should also consider that if eight anti-synthetase antibodies have been identified to date, at least another 12 aminoacyl-tRNA synthetase enzymes exist, and that the entire spectrum of anti-synthetase antibodies is not covered by any of the existing commercially available tests. All these points clearly indicate the risk that anti-synthetase antibody positivity could be underestimated and that it could be clustered in IPAF. This evidence clearly suggests that well-established and clinically based ASSD classification criteria are needed to reduce the risk of stratifying patients across specialties, in areas that may contribute to real-time incorrectly diagnosed primary disease. Recently, the CLASS (classification criteria of anti-synthetase syndrome) project has been funded by the American College of Rheumatology and the European League against Rheumatism. The aim of the project is to define clinically based criteria of ASSD involving a large number of rheumatology, pulmonology, dermatology, immunology and internal medicine centres expert in the management of rheumatoid arthritis, systemic sclerosis, Sjogren's syndrome and other lung fibrosing conditions. From a scientific point of view, by putting together different specialists we hope to solve the daily discussions about “anti-synthetase antibody positive patient classification” that may delay the correct approach and treatment of affected patients.

IPAF classification criteria include several autoimmune conditions with different evolution. The progression into established CTD is common and a continuous up-to-date process of classification criteria of both IPAF and CTD is mandatory.http://ow.ly/pXNW30knUzl

Exercise-based evaluations and interventions for pulmonary hypertension with connective tissue disorders

INTRODUCTION

Exercise intolerance is a common and often significant limitation in pulmonary arterial hypertension (PAH). This intolerance greatly affects the quality of life and function of the individual with PAH, irrespective of its etiology. In PAH associated with connective tissue disorders (PAH-CTD), exercise intolerance is further amplified by the presence of coexisting musculoskeletal manifestations of CTD. The evaluation of exercise capacity and prescription for exercise training therefore becomes a challenge to the clinician. Areas covered: This review highlights factors contributing to exercise intolerance in PAH-CTD, evaluation methods of exercise capacity and an overview on exercise training and a roadmap for future research. Expert commentary: Exercise intolerance is a complex interplay of cardiovascular, pulmonary, and musculoskeletal systems. Data from cardiopulmonary exercise tests have shown predictive abilities for both diagnosis and prognosis. In its absence, the 6-min walk test can be used to provide similar information thereby making the role of exercise testing an invaluable evaluation method in PAH-CTD. Exercise training data in PAH-CTD are still sparse, though, data from PAH studies suggest potential benefit. However, more research is required in this area of testing and training for greater understanding on exercise hemodynamic, phenotypes, and training benefits.

Prevalence of primary Sjögren's syndrome in patients undergoing evaluation for pulmonary arterial hypertension

Background

The prevalence of pulmonary arterial hypertension (PAH) in primary Sjögren’s syndrome (SS) had been reported to be rare. However, recent studies using echocardiography as a screening method showed conflicting results, and the true prevalence is still unclear. Since diagnosing primary SS is difficult because of its heterogeneous nature, a number of patients with primary-SS-associated PAH may be misdiagnosed with idiopathic PAH, losing their chance to undergo immunosuppressive therapy. Therefore, we sought to elucidate the prevalence of primary SS among patients who initially present with PAH.

Methods

From our prospective institutional PAH database, 40 consecutive patients without any obvious cause of PAH at the time of PAH diagnosis were identified. We retrospectively evaluated the prevalence of primary SS diagnosed during or after the initial assessment of PAH.

Results

During the initial assessment, one patient was diagnosed with primary-SS-associated PAH. Among the 25 patients who were initially diagnosed with idiopathic PAH, five were diagnosed with primary SS during their course of the disease. Of the five patients, three had key signs suggesting primary SS and were probably underdiagnosed at the time of initial evaluation. The remaining two patients, who were finally diagnosed with primary SS, did not have any specific signs suggesting primary SS at the time of initial evaluation but showed positive conversion of their autoantibodies during the course of PAH.

Conclusion

The prevalence of primary-SS-associated PAH may be relatively high among patients who undergo initial evaluation for PAH. Furthermore, primary-SS-associated PAH may be underdiagnosed with routine evaluation for the primary cause of PAH. Clinicians should pay specific attention and carefully evaluate the possibility of primary SS in patients with PAH.

Systemic sclerosis

Systemic sclerosis, also called scleroderma, is an immune-mediated rheumatic disease that is characterised by fibrosis of the skin and internal organs and vasculopathy. Although systemic sclerosis is uncommon, it has a high morbidity and mortality. Improved understanding of systemic sclerosis has allowed better management of the disease, including improved classification and more systematic assessment and follow-up. Additionally, treatments for specific complications have emerged and a growing evidence base supports the use of immune suppression for the treatment of skin and lung fibrosis. Some manifestations of the disease, such as scleroderma renal crisis, pulmonary arterial hypertension, digital ulceration, and gastro-oesophageal reflux, are now treatable. However, the burden of non-lethal complications associated with systemic sclerosis is substantial and is likely to become more of a challenge. Here, we review the clinical features of systemic sclerosis and describe the best practice approaches for its management. Furthermore, we identify future areas for development.

Nailfold capillaroscopic changes in patients with idiopathic pulmonary arterial hypertension and systemic sclerosis-related pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) represents one of the main clinical expressions of the vascular changes in systemic sclerosis (SSc). Lung microvascular changes can play a role in the pathogenesis of idiopathic PAH (IPAH) also. The aim of this study is to investigate the presence of capillaroscopic abnormalities in patients with IPAH and to evaluate the differences in capillary nailfold changes between patients with IPAH and patients with SSc with and without PAH.

METHODS

39 SSc patients (19 with PAH - SSc-PAH and 20 without - SSc-noPAH), 21 subjects with IPAH and 20 healthy subjects were recruited. PAH was diagnosed by right heart catheterization. Nailfold videocapillaroscopy was performed (NVC) in all recruited subjects; capillary quantitative parameters (loops length and width, capillary density, neoangiogenesis) were evaluated and a semiquantitative scoring was used (normal, minor or major abnormalities for healthy controls and IPAH subjects and specific patterns - early, active and late - for SSc subjects) to define microvascular alterations.

RESULTS

The presence of capillaroscopic abnormalities was detected in 38,1% subjects with IPAH; particularly, compared to healthy controls, capillary density was significantly lower (7,5±1,65loops/mm vs 9±1,37loops/mm p<0,05) and mean capillary width was significantly higher (21±13μm vs 17±3μm p<0,05). A more severe NVC pattern (active/late) was described. SSc-PAH patients compared to SSc-noPAH patients (73,2% vs 50% respectively, p<0,05), with a significantly lower capillary density (5,64±1,9loops/mm vs 6,5±1,3loops/mm p<0,05) and a significantly higher capillary width (55±7μm vs 35±8μm - p<0,05) and mean number of neoangiogenesis (N/mm) (1±0,33 vs 0,2±0,22 respectively p<0,05).

CONCLUSIONS

These data, beyond to confirm the role of microvascular damage in SSc-related PAH, support the hypothesis of systemic microvascular involvement in IPAH also, which can be detected by NVC, although further studies are needed to establish whether the changes in the systemic microcirculation are causal or consequential to PAH.