Future Needs in Mast Cell Biology.

The pathophysiological roles of mast cells are still not fully understood, over 140 years since their description by Paul Ehrlich in 1878. Initial studies have attempted to identify distinct "subpopulations" of mast cells based on a relatively small number of biochemical characteristics. More recently, "subtypes" of mast cells have been described based on the analysis of transcriptomes of anatomically distinct mouse mast cell populations. Although mast cells can potently alter homeostasis, in certain circumstances, these cells can also contribute to the restoration of homeostasis. Both solid and hematologic tumors are associated with the accumulation of peritumoral and/or intratumoral mast cells, suggesting that these cells can help to promote and/or limit tumorigenesis. We suggest that at least two major subsets of mast cells, MC1 (meaning anti-tumorigenic) and MC2 (meaning pro-tumorigenic), and/or different mast cell mediators derived from otherwise similar cells, could play distinct or even opposite roles in tumorigenesis. Mast cells are also strategically located in the human myocardium, in atherosclerotic plaques, in close proximity to nerves and in the aortic valve. Recent studies have revealed evidence that cardiac mast cells can participate both in physiological and pathological processes in the heart. It seems likely that different subsets of mast cells, like those of cardiac macrophages, can exert distinct, even opposite, effects in different pathophysiological processes in the heart. In this chapter, we have commented on possible future needs of the ongoing efforts to identify the diverse functions of mast cells in health and disease

The N-Formyl Peptide Receptors and Rheumatoid Arthritis: A Dangerous Liaison or Confusing Relationship?

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by a progressive symmetric inflammation of the joints resulting in bone erosion and cartilage destruction with a progressive loss of function and joint deformity. An increased number of findings support the role of innate immunity in RA: many innate immune mechanisms are responsible for producing several cytokines and chemokines involved in RA pathogenesis, such as Tumor Necrosis Factor (TNF)-α, interleukin (IL)-6, and IL-1. Pattern recognition receptors (PRRs) play a crucial role in modulating the activity of the innate arm of the immune response. We focused our attention over the years on the expression and functions of a specific class of PRR, namely formyl peptide receptors (FPRs), which exert a key function in both sustaining and resolving the inflammatory response, depending on the context and/or the agonist. We performed a broad review of the data available in the literature on the role of FPRs and their ligands in RA. Furthermore, we queried a publicly available database collecting data from 90 RA patients with different clinic features to evaluate the possible association between FPRs and clinic-pathologic parameters of RA patients

Cardiovascular abnormalities and impaired exercise performance in adolescents with congenital adrenal hyperplasia

Context: Patients with classic Congenital Adrenal Hyperplasia (CAH) are treated with lifelong glucocorticoids (GCS). Cardiovascular (CV) and metabolic effects of such therapy in adolescents have never been quantified. Objective: To investigate left ventricular (LV) morphology, function and exercise performance in adolescents with CAH. Design and Setting: cross-sectional and controlled study conducted at a tertiary referral centre. Patients: Twenty patients with classic CAH (10 females) aged 13.6±2.5 years and 20 healthy controls comparable for sex and pubertal status were enrolled in the study and compared to a group of 18 patients without CAH receiving a similar dose of GCS for Juvenile Idiopathic Arthritis (JIA). Main Outcomes Measures: Echocardiographic assessment and symptom-limited exercise testing were performed. Anthropometric, hormonal and biochemical parameters were also measured. Results: Compared to healthy controls, patients with CAH exhibited an increased BMI (p<0.001), waist-to-height ratio (p<0.001), percentage of body fat (p<0.001) as well as higher insulin concentrations and HOMA index even after adjustment for BMI (p=0.03 and p=0.05, respectively). Moreover, CAH patients exhibited an impaired exercise capacity as shown by reduced peak workload (99±27 vs 126±27 W, p<0.01) and higher systolic blood pressure response at peak (156±18 vs 132±11 mmHg, p<0.01; Δ=45±24 vs 22±10 mmHg, p=0.05) with respect to healthy controls. CAH males displayed mild LV diastolic dysfunction as documented by significant prolongation of both isovolumic relaxation time (IRT) (118±18 vs 98±11ms, p<0.05) and mitral deceleration time (MDT) (138±25 vs 111±15 ms, p<0.01). No significant differences in CV function were found between CAH and JIA patients. Conclusion: Adolescents with CAH exhibit impaired exercise performance and enhanced systolic blood pressure response during exercise. In our population, such abnormalities appear related to GCS therapy rather than CAH per se. CAH males, but no females, present mild LV diastolic dysfunction that correlates with testosterone concentrations suggesting a sex hormone related difference

Neurologic and Psychiatric Manifestations of Bradykinin-Mediated Angioedema: Old and New Challenges

Neurologic manifestations have been occasionally described in patients with bradykinin-mediated angioedema. The existing literature is currently limited to case series and case reports mainly described in the hereditary forms (HAE) concerning central nervous system (CNS) involvement. On the contrary, very little is known about peripheral and autonomic nervous system manifestations. CNS involvement in HAE may present with symptoms including severe headaches, visual disturbance, seizures, and various focal and generalized deficits. In addition, a stroke-like clinical picture may present in HAE patients. In turn, some drugs used in patients with cardiovascular and neurologic disorders, such as recombinant tissue plasminogen activator (r-tPA) and angiotensin-converting enzyme inhibitors (ACEI), may produce medication-induced angioedema, resulting in a diagnostic challenge. Finally, most patients with HAE have higher levels of psychological distress, anxiety, and depression. With this review, we aimed to provide an organized and detailed analysis of the existing literature on neurologic and psychiatric manifestations of HAE to shed light on these potentially invalidating symptoms and lay the foundation for further personalized diagnostic pathways for patients affected by this protean disease

Endothelial-to-mesenchymal transition contributes to endothelial dysfunction and dermal fibrosis in systemic sclerosis

Objective: Systemic sclerosis (SSc) features multiorgan fibrosis orchestrated predominantly by activated myofibroblasts. Endothelial-to-mesenchymal transition (EndoMT) is a transdifferentiation by which endothelial cells (ECs) lose their specific morphology/markers and acquire myofibroblast-like features. Here, we determined the possible contribution of EndoMT to the pathogenesis of dermal fibrosis in SSc and two mouse models. Methods: Skin sections were immunostained for endothelial CD31 or vascular endothelial (VE)-cadherin in combination with α-smooth muscle actin (α-SMA) myofibroblast marker. Dermal microvascular ECs (dMVECs) were prepared from SSc and healthy skin (SSc-dMVECs and H-dMVECs). H-dMVECs were treated with transforming growth factor-β1 (TGFβ1) or SSc and healthy sera. Endothelial/mesenchymal markers were assessed by real-time PCR, immunoblotting and immunofluorescence. Cell contractile phenotype was assayed by collagen gel contraction. Results: Cells in intermediate stages of EndoMT were identified in dermal vessels of either patients with SSc or bleomycin-induced and urokinase-type plasminogen activator receptor (uPAR)-deficient mouse models. At variance with H-dMVECs, SSc-dMVECs exhibited a spindle-shaped appearance, co-expression of lower levels of CD31 and VE-cadherin with myofibroblast markers (α-SMA+ stress fibres, S100A4 and type I collagen), constitutive nuclear localisation of the EndoMT driver Snail1 and an ability to effectively contract collagen gels. Treatment of H-dMVECs either with SSc sera or TGFβ1 resulted in the acquisition of a myofibroblast-like morphology and contractile phenotype and downregulation of endothelial markers in parallel with the induction of mesenchymal markers. Matrix metalloproteinase-12-dependent uPAR cleavage was implicated in the induction of EndoMT by SSc sera. Conclusions: In SSc, EndoMT may be a crucial event linking endothelial dysfunction and development of dermal fibrosis

Predictive Response to Immunotherapy Score: A Useful Tool for Identifying Eligible Patients for Allergen Immunotherapy

A specific predictive tool of allergen immunotherapy (AIT) outcome has not been identified yet. This study aims to evaluate the efficacy of a disease score referred to as Predictive Response to Immunotherapy Score (PRIS) to predict the response to AIT and identify eligible patients. A total of 110 patients diagnosed with allergic rhinitis with or without concomitant asthma were enrolled in this study. Before beginning sublingual immunotherapy (SLIT), patients were evaluated by analyzing clinical and laboratory parameters. A specific rating was assigned to each parameter to be combined in a total score named PRIS. At baseline (T0) and follow-up [after 12 (T12) and 24 months (T24) of SLIT], a Visual Analogue Scale (VAS) was used to calculate a mean symptom score (MSS). Finally, the percentage variation between the MSS at T0 and at T12 [ΔMSS-12(%)] and T24 [ΔMSS-24 (%)] was measured. We observed a significant improvement of symptoms at T12 and T24 compared to T0 in all groups undergoing SLIT. PRIS was effective in predicting ΔMSS-24 (%) in patients treated with single-allergen SLIT. In addition, PRIS was effective in predicting ΔMSS-24 (%) in both patients with only rhinitis and with concomitant asthma. PRIS assessment can represent a useful tool to individuate potential responders before SLIT prescription

Immunogenicity and Safety of Anti-SARS-CoV-2 mRNA Vaccines in a Cohort of Patients with Hereditary Angioedema

Many factors may trigger hereditary angioedema (HAE) attacks. This study aims to gain insights into the benefits and potential risks of COVID-19 vaccination in HAE patients, focusing particularly on the possibility of triggering attacks. We enrolled 31 patients with HAE undergoing two doses of the SARS-CoV-2 mRNA Comirnaty-BioNTech/Pfizer vaccine. To evaluate the possible influence of the vaccine on disease control and attack frequency, we administered the angioedema control test (AECT) 4-week version before (T0), 21 days after the first dose (T1), and between 21 and 28 days after the second dose (T2). Despite 5 patients (16.1%) experiencing attacks within 72 h of the first dose administration, no significant variation in attack frequency was observed before and after vaccination [F(2,60) = 0.123; p = 0.799]. In addition, patients reported higher AECT scores at T1 and T2 compared to T0 [F(2,44) = 6.541; p < 0.05; post hoc p < 0.05)], indicating that the disease was rather more controlled after vaccinations than in the previous period. All patients showed a positive serological response to the vaccine without significant differences from healthy controls (U = 162; p = 0.062). These observations suggest that the vaccine administration is safe and effective in HAE patients

67 kDa laminin receptor (67LR) in normal and neoplastic hematopoietic cells: is its targeting a feasible approach?

The 67 kDa laminin receptor (67LR) is a non-integrin cell surface receptor for laminin (LM) that derives from a 37 kDa precursor (37LRP). 67LR expression is increased in neoplastic cells and correlates with an enhanced invasive and metastatic potentialin many human solid tumors, recommending this receptor as a new promising target for cancer therapy. This is supported by in vivo studies showing that 67LR downregulation reduces tumour cell proliferation and tumour formation by inducing apoptosis. 67LR association with the anti-apoptotic protein PED/PEA-15 activates a signal transduction pathway, leading to cell proliferation and resistance to apoptosis. However, the main function of 67LR is to enhance tumor cell adhesion to the LM of basement membranes and cell migration, two crucial events in the metastasis cascade.Thus, inhibition of 67LR binding to LM has been proved to be a feasible approach to block metastatic cancer cell spread. Despite accumulating evidences on 67LR overexpression in hematologic malignancies, 67LR role in these diseases has not been clearly defined. Here, we review 67LR expression and function in normal and malignant hematopoietic cells, 67LR role and prognostic impact in hematological malignancies and first attempts in targeting its activity