Photon-counting computed tomography in the assessment of rheumatoid arthritis-associated interstitial lung disease: an initial experience

PURPOSE: Interstitial lung disease (ILD) accounts for a significant proportion of mortality and morbidity in patients with rheumatoid arthritis (RA). The aim of this cross-sectional study is to evaluate the performance of novel photon-counting detector computed tomography (PCD-CT) in the detection of pulmonary parenchymal involvement. METHODS: Sixty-one patients with RA without a previous definitive diagnosis of ILD underwent high-resolution (HR) (0.4 mm slice thickness) and ultra-high-resolution (UHR) (0.2 mm slice thickness) PCDCT examination. The extent of interstitial abnormalities [ground-glass opacity (GGO), reticulation, bronchiectasis, and honeycombing] were scored in each lobe using a Likert-type scale. Total ILD scores were calculated as the sum of scores from all lobes. RESULTS: Reticulation and bronchiectasis scores were higher in the UHR measurements taken compared with the HR protocol [median (quartile 1, quartile 3): 2 (0, 3.5) vs. 0 (0, 3), P < 0.001 and 2 (0, 2) vs. 0 (0, 2), P < 0.001, respectively]; however, GGO and honeycombing scores did not differ [2 (2, 4) vs. 2 (2, 4), P = 0.944 and 0 (0, 0) vs. 0 (0, 0), P = 0.641, respectively]. Total ILD scores from both HR and UHR scans showed a mild negative correlation in diffusion capacity for carbon monoxide (HR: r = -0.297, P = 0.034; UHR: r = -0.294, P = 0.036). The pattern of lung parenchymal involvement did not differ significantly between the two protocols. The HR protocol had significantly lower volume CT dose index [0.67 (0.69, 1.06) mGy], total dose length product [29 (24.48, 33.2) mGy*cm] compared with UHR scans [8.18 (6.80, 9.23) mGy, P < 0.001 and 250 (218, 305) mGy*cm, P < 0.001]. CONCLUSION: UHR PCD-CT provides more detailed information on ILD in patients with RA than low-dose HR PCDCT. HR PCD-CT image acquisition with a low effective radiation dose may serve as a valuable, low-radiation screening tool in the selection of patients for further, higher-dose UHR PCD-CT screening.

Proteomic Changes of Osteoclast Differentiation in Rheumatoid and Psoriatic Arthritis Reveal Functional Differences.

Background: Osteoclasts play a crucial role in the maintenance, repair, and remodeling of bones of the adult vertebral skeleton due to their bone resorption capability. Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are associated with increased activity of osteoclasts. Objectives: Our study aimed to investigate the dynamic proteomic changes during osteoclast differentiation in healthy donors, in RA, and PsA. Methods: Blood samples of healthy donors, RA, and PsA patients were collected, and monocytes were isolated and differentiated into osteoclasts in vitro using macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor κB ligand (RANK-L). Mass spectrometry-based proteomics was used to analyze proteins from cell lysates. The expression changes were analyzed with Gene Set Enrichment Analysis (GSEA). Results: The analysis of the proteomic changes revealed that during the differentiation of the human osteoclasts, expression of the proteins involved in metabolic activity, secretory function, and cell polarity is increased; by contrast, signaling pathways involved in the immune functions are downregulated. Interestingly, the differences between cells of healthy donors and RA/PsA patients are most pronounced after the final steps of differentiation to osteoclasts. In addition, both in RA and PsA the differentiation is characterized by decreased metabolic activity, associated with various immune pathway activities; furthermore by accelerated cytokine production in RA. Conclusions: Our results shed light on the characteristic proteomic changes during human osteoclast differentiation and expression differences in RA and PsA, which reveal important pathophysiological insights in both diseases.

Impact of Medium-Sized Extracellular Vesicles on the Transduction Efficiency of Adeno-Associated Viruses in Neuronal and Primary Astrocyte Cell Cultures.

(1) Adeno-associated viruses (AAV) are safe and efficient gene therapy vectors with promising results in the treatment of several diseases. Extracellular vesicles (EV) are phospholipid bilayer-surrounded structures carrying several types of lipids, proteins, and nucleic acids with the ability to cross biological barriers. EV-associated AAVs might serve as new and efficient gene therapy vectors considering that they carry the benefits of both AAVs and EVs. (2) We tested vesicle-associated AAVs and vesicles mixed with AAVs on two major cell types of the central nervous system: a neural cell line (N2A) and primary astrocyte cells. (3) In contrast to previously published in vivo observations, the extracellular vesicle packaging did not improve but, in the case of primary astrocyte cells, even inhibited the infection capacity of the AAV particles. The observed effect was not due to the inhibitory effects of the vesicles themselves, since mixing the AAVs with extracellular vesicles did not change the effectiveness. (4) Our results suggest that improvement of the in vivo efficacy of the EV-associated AAV particles is not due to the enhanced interaction between the AAV and the target cells, but most likely to the improved delivery of the AAVs through tissue barriers and to the shielding of AAVs from neutralizing antibodies.

Transarticular epithelioid hemangioma of the ankle-a case of a rare vascular neoplasm.

Epithelioid hemangioma of the bone is a rare kind of vascular neoplasm posing a diagnostic challenge because of its ability to mimic malignant tumors. We report a case of a fast-growing, talofibular joint-involving epithelioid hemangioma, which was suspectedly initiated by vascular damage due to trauma and arthroscopy. The ankle mass appeared as a lytic lesion on the CT images and as a T1 hypo-, T2 mildly hyperintense, lobulated structure on the MRI scans. The contrast enhancement pattern was typical to vascular neoplasms. Histologically the lesion consisted of well-formed vessels lined with epithelioid cells with a slightly atypical nuclear morphology, inflammation with a significant number of eosinophils, and low mitotic rate. Immunohistochemistry analysis showed the presence of vascular markers but no rearrangements characteristic of soft tissue sarcomas were registered by the next-generation sequencing. The surgical treatment was curative. The report presents current imaging methods and summarizes the imaging findings of transarticular spreading tumors. The paper also highlights that for the differential diagnosis of vascular tumors showing signs of aggressivity, the pathological analysis is inevitable. Correct diagnosis of the epithelioid hemangioma is essential, as the treatment of more malignant entities is substantially different. An added value of the report is that to the best of our knowledge, a transarticular spreading epithelioid hemangioma of the ankle has never been described before.

Distinct In Vitro T-Helper 17 Differentiation Capacity of Peripheral Naive T Cells in Rheumatoid and Psoriatic Arthritis.

Background: The T-helper 17 (Th17) cells have a prominent role in inflammation as well as in bone and join destruction in both rheumatoid and psoriatic arthritis (RA and PsA). Here, we studied Th17 cell differentiation in RA and PsA. Methods: Blood samples from healthy donors, RA and PsA patients were collected. CD45RO- (naive) and CD45RO+ (memory) T cells were isolated from peripherial blood mononuclear cell by magnetic separation. Naive T cells were stimulated with anti-CD3, anti-CD28, and goat anti-mouse IgG antibodies and treated with transforming grow factor beta, interleukin (IL)-6, IL-1ß, and IL-23 cytokines and also with anti-IL-4 antibody. IL-17A and IL-22 production were measured by enzyme linked immunosorbent assay, RORC, and T-box 21 (TBX21) expression were analyzed by quantitative polymerase chain reaction and flow cytometry. C-C chemokine receptor 6 (CCR6), CCR4, and C-X-C motif chemokine receptor 3 expression were determined by flow cytometry. Cell viability was monitored by impedance-based cell analyzer (CASY-TT). Results: RORC, TBX21, CCR6, and CCR4 expression of memory T cells of healthy individuals (but not RA or PsA patients) were increased (p < 0.01; p < 0.001; p < 0.05; p < 0.05, respectively) compared to the naive cells. Cytokine-induced IL-17A production was different in both RA and PsA patients when compared to healthy donors (p = 0.0000026 and p = 0.0001047, respectively). By contrast, significant differences in IL-22 production were observed only between RA versus healthy or RA versus PsA patients (p = 0.000006; p = 0.0013454, respectively), but not between healthy donors versus PsA patients. Conclusion: The naive CD4 T-lymphocytes are predisposed to differentiate into Th17 cells and the in vitro Th17 cell differentiation is profoundly altered in both RA and PsA.

Extracellular vesicles regulate the human osteoclastogenesis: divergent roles in discrete inflammatory arthropathies.

OBJECTIVE: Extracellular vesicles (EVs) are subcellular signalosomes. Although characteristic EV production is associated with numerous physiological and pathological conditions, the effect of blood-derived EVs on bone homeostasis is unknown. Herein we evaluated the role of circulating EVs on human osteoclastogenesis. METHODS: Blood samples from healthy volunteers, rheumatoid arthritis (RA) and psoriatic arthritis (PsA) patients were collected. Size-based EV sub-fractions were isolated by gravity-driven filtration and differential centrifugation. To investigate the properties of EV samples, resistive pulse sensing technique, transmission electron microscopy, flow cytometry and western blot were performed. CD14+ monocytes were separated from PBMCs, and stimulated with recombinant human M-CSF, RANKL and blood-derived EV sub-fractions. After 7 days, the cells were fixed and stained for tartrate-resistant acid phosphatase and counted. RESULTS: EVs isolated by size-based sub-fractions were characterized as either microvesicles or exosomes (EXO). Healthy (n = 11) and RA-derived (n = 12) EXOs profoundly inhibited osteoclast differentiation (70%, p < 0.01; 65%, p < 0.01, respectively). In contrast, PsA-derived (n = 10) EXOs had a stimulatory effect (75%, p < 0.05). In cross-treatment experiments where EXOs and CD14+ cells were interchanged between the three groups, only healthy (n = 5) and RA (n = 5)-derived EXOs inhibited (p < 0.01, respectively) the generation of osteoclasts in all groups, whereas PsA (n = 7)-derived EXOs were unable to mediate this effect. CONCLUSIONS: Our data suggest that blood-derived EXOs are novel regulators of the human osteoclastogenesis and may offer discrete effector function in distinct inflammatory arthropathies.

The Emerging and Diverse Roles of Src-Like Adaptor Proteins in Health and Disease.

Although Src-like adaptor proteins (SLAP-1 and SLAP-2) were mainly studied in lymphocytes, where they act as negative regulators and provide fine control of receptor signaling, recently, several other functions of these proteins were discovered. In addition to the well-characterized immunoregulatory functions, SLAP proteins appear to have an essential role in the pathogenesis of type I hypersensitivity, osteoporosis, and numerous malignant diseases. Both adaptor proteins are expressed in a wide variety of tissues, where they have mostly inhibitory effects on multiple intracellular signaling pathways. In this review, we summarize the diverse effects of SLAP proteins.