Levels of C-reactive protein associated with high and very high cardiovascular risk are prevalent in patients with rheumatoid arthritis.

ObjectiveC-reactive protein (CRP) levels>3 mg/L and>10 mg/L are associated with high and very high cardiovascular risk, respectively, in the general population. Because rheumatoid arthritis (RA) confers excess cardiovascular mortality, we determined the prevalence of these CRP levels among RA patients stratified on the basis of their RA disease activity.MethodsWe evaluated physician and patient global assessments of disease activity, tender and swollen 28 joint counts, erythrocyte sedimentation rate (ESR), and CRP measured in a single clinic visit for 151 RA patients. Disease activity was calculated using the Clinical Disease Activity Index (CDAI) and the Disease Activity Score 28 Joints (DAS28-ESR and DAS28-CRP).ResultsMedian CRP level was 5.3 mg/L. 68% of patients had CRP>3 mg/L, and 25% had CRP>10 mg/L. Of those with 0-1 swollen joints (n = 56), or 0-1 tender joints (n = 81), 64% and 67%, respectively, had CRP>3 mg/L, and 23% and 20%, respectively, had CRP>10 mg/L. Of those with remission or mildly active disease by CDAI (n = 58), DAS28-ESR (n = 39), or DAS28-CRP (n = 70), 49-66% had CRP>3 mg/L, and 10-14% had CRP>10 mg/L. Of patients with moderate disease activity by CDAI (n = 51), DAS28-ESR (n = 78), or DAS28-CRP (n = 66), 67-73% had CRP>3 mg/L, and 25-33% had CRP>10 mg/L.ConclusionEven among RA patients whose disease is judged to be controlled by joint counts or standardized disease scores, a substantial proportion have CRP levels that are associated high or very high risk for future cardiovascular events in the general population

Sphingosine-1-phosphate promotes the persistence of activated CD4 T cells in inflamed sites

Inflammation can be protective or pathogenic depending on context and timeframe. Acute inflammation, including the accumulation of CD4 T cells, accompanies protective immune responses to pathogens, but the presence of activated CD4 T cells at sites of inflammation is associated with chronic inflammatory disease. While significant progress has been made in understanding the migration of CD4 T cells into inflamed sites, the signals that lead to their persistence are poorly characterized. Using a murine ear model of acute inflammation and intravital two-photon imaging, we have dissected the signals that mediate CD4 T cell persistence. We report the unexpected finding that the bioactive lipid, sphingosine-1-phosphate (S1P), is both necessary and sufficient for the persistence of activated CD4 T cells at peripheral tissues in acute inflammation. S1P mediated the enhanced motility of CD4 T cells at inflamed tissues but did not affect their migration to the downstream draining lymph node. We found that sphingosine kinase-1, which regulates S1P production is increased at inflamed sites in mice and in patients with the chronic inflammatory disease, rheumatoid arthritis. Together, these data suggest that S1P, or its regulators, may be key targets to promote or disrupt accumulation of CD4 T cells at inflamed tissues

Ultrasound imaging in joint and soft tissue inflammation

The use of ultrasound as an extended and more objective investigation performed as an extension of physical examination has a potential role in studying inflammation in different rheumatic diseases such as rheumatoid arthritis (RT) and spondylarthropathy (SpA). Rheumatoid arthritis is a chronic disease causing joint inflammation and destruction. Metacarpophalangeal (MCP) joint involvement is one of the earliest and most permanent signs of RA. US has been used to detect synovitis and erosions in MCP joints with high accuracy when compared to X-ray and magnetic resonance imaging (MRI). In RA joints, power Doppler has been used to detect increased blood flow as a potential sign of inflammation but grey-scale and power Doppler ultrasonography was not compared to another method to detect increased blood flow in MCP joints. After RA the next most common inflammatory group of diseases are the seronegative spondylarthropathies. In SpA joint inflammation and ankylosis occur in addition to periarticular enthesitis, which is one of the major hallmarks of the disease and has been poorly studied by ultrasonography. In order to reduce observer variation in musculoskeletal ultrasound examination to the level of other imaging methods it is necessary to avoid direct contact between the observer and the subject. This problem has been addressed in the aerospace industry and led to the development of air-coupled non-destructive testing. Air-coupled ultrasonography has the potential in medial imaging to exclude observer variation if it is able to depict human anatomy. There are currently no data regarding airborne ultrasound in the musculoskeletal ultrasound literature

Biomarkers of inflammatory arthritis and proteomics

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Urinary proteomics can define distinct diagnostic inflammatory arthritis subgroups

Current diagnostic tests applied to inflammatory arthritis lack the necessary specificity to appropriately categorise patients. There is a need for novel approaches to classify patients with these conditions. Herein we explored whether urinary proteomic biomarkers specific for different forms of arthritis (rheumatoid arthritis (RA), psoriatic arthritis (PsA), osteoarthritis (OA)) or chronic inflammatory conditions (inflammatory bowel disease (IBD)) can be identified. Fifty subjects per group with RA, PsA, OA or IBD and 50 healthy controls were included in the study. Two-thirds of these populations were randomly selected to serve as a training set, while the remaining one-third was reserved for validation. Sequential comparison of one group to the other four enabled identification of multiple urinary peptides significantly associated with discrete pathological conditions. Classifiers for the five groups were developed and subsequently tested blind in the validation test set. Upon unblinding, the classifiers demonstrated excellent performance, with an area under the curve between 0.90 and 0.97 per group. Identification of the peptide markers pointed to dysregulation of collagen synthesis and inflammation, but also novel inflammatory markers. We conclude that urinary peptide signatures can reliably differentiate between chronic arthropathies and inflammatory conditions with discrete pathogenesis

The role of the cytokines IL-17A and IL-33 in inflammatory arthritis and psoriasis

The inflammatory autoimmune diseases rheumatoid arthritis, psoriatic arthritis and psoriasis have seen a break through in therapy by targeting cytokines in the last decade. Interleukin-17A, a potential new target, is considered as a crucial player in rheumatoid arthritis, and has been suggested to be produced by CD4+ T cells (Th17 cells). I explored the cellular sources of IL-17A in human established RA synovium. Surprisingly, only a small proportion of IL-17 positive cells were T cells without expression of a Th17 marker CCR6. Unexpectedly, the majority of IL-17A expression colocalized within mast cells. These data do not contradict a crucial role for IL-17A in RA pathogenesis, however, suggest that in addition to Th17 cells, cells of the innate immune system, particularly mast cells, may be an important component of the effector IL-17A response. Psoriasis is a common chronic autoimmune disease of the skin characterized by hyperplasia of epidermal keratinocytes with associated inflammation. IL-33 is a new member of the IL-1 superfamily that signals through the ST2 receptor and was originally defined as an inducer of T helper 2 (Th2) cytokines. Recently broader immune potential has been discovered for IL-33 particularly via mast cell activation. With its expression at body barrier surfaces it is assumed to act as an alarmin. In this thesis I demonstrate that IL-33 expression is up-regulated in the epidermis of psoriatic lesions, compared to healthy skin, thus indicating that IL-33 may be a mediator regulating crosstalk between keratinocytes and infiltrating immune cells in psoriatic plaques. In a phorbol ester-induced model of skin inflammation ST2-/- mice exhibited reduced cutaneous inflammatory responses compared to WT mice. Furthermore, consecutive injections of IL-33 into the ears of mice induced a psoriasis-like inflammatory lesion. This was partially mast cell dependent and cellular analysis demonstrated recruitment of neutrophils to the ear. This concludes that IL-33, via activation of mast cells and recruitment of neutrophils, may play a role in psoriasis plaque inflammation. In the last part of the thesis I tested if nanoparticles can be utilized to image cytokine driven inflammation. Bio-linkages with protein-nanoparticles have been established and in vivo detection of nanoparticles performed. This final interdisciplinary outlook demonstrates a still to be established/finalized method with great potential

Development of Portable Diffuse Optical Spectroscopic Systems For Treatment Monitoring

The goal of this dissertation is to demonstrate the utility of portable, small-scale diffuse optical spectroscopic (DOS) systems for the diagnosis and treatment monitoring of various diseases. These systems employ near-infrared light (wavelength range of 650nm to 950nm) to probe human tissue and are sensitive to changes in scattering and absorption properties of tissues. The absorption is mainly influenced by the components of blood, namely oxy- and deoxy-hemoglobin (HbO2 and Hb) and parameters that can be derived from them (e.g. total hemoglobin concentration [THb] and oxygen saturation, StO2). Therefore, I focused on diseases in which these parameters change, which includes vascular diseases such as Peripheral Atrial Disease (PAD) and Infantile Hemangiomas (IH) as well as musculoskeletal autoimmune diseases such as Rheumatoid Arthritis (RA). In each of these specific diseases, current monitoring techniques are limited by their sensitivity to disease progression or simply do not exist as a quantitative metric. As part of this project, I first designed and built a wireless handheld DOS device (WHDD) that can perform DOS measurements at various tissue depths. This device was used in a 15-patient pilot study for infantile hemangiomas (IH) to differentiate diseased skin from normal skin and monitor the vascular changes during intervention. In another study, I compare the ultra-small form- factor WHDD’s ability to monitor synovitis and disease progression during a patient’s treatment of RA against the capabilities of a proven frequency domain optical tomographic (FDOT) system that has shown to differentiate patients with and without RA. Learning from clinical utility of the WHDD from these two studies, I adapted the WHDD technology to develop a compact multi- channel DOS measurement system to monitor perfusion changes in the lower extremities before and after surgical intervention for patients with peripheral artery disease (PAD). Using this multi- channel system, which we called the vascular optical spectroscopic measurement (VOSM) system, our group conducted a 20-subject pilot study to quantify its ability to monitor blood perfusion before and after revascularization of stenotic arteries in the lower extremities. This proof-of- concept study demonstrated how DOS may help vascular surgeons perform revascularization procedures in the operating room and assists in post-operative treatment monitoring of vascular diseases

Imaging of joints with laser‐based photoacoustic tomography: An animal study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134964/1/mp4166.pd