Vascular function in rheumatoid arthritis: intermediate phenotypes and cardiovascular risk

Possible Modulation of Vascular Function Measures in Rheumatoid Arthritis by Homocysteine

The effect of homocysteine on cardiovascular diseases is still equivocal, especially in rheumatoid arthritis patients. In this investigation, the association between homocysteine with blood flow and vascular resistance in rheumatoid arthritis was examined. Serum levels of homocysteine were determined in thirty-one rheumatoid arthritis patients and nineteen apparently healthy subjects using ELISA. Additionally, strain-gauge plethysmography was used to determine both forearm blood flow and vascular function at rest and after occlusion. Forearm occlusion blood flow (patients: 21.9 ± 6.55 versus control: 25.5 ± 6.10ml/100mL/min) was lower (p < 0.05) while occlusion vascular resistance (patients: 4.77 ± 2.08 versus controls 3.05 ± 0.96U) was greater (p < 0.01) in rheumatoid arthritis than in the controls. Level of serum homocysteine was similar (p = 0.803) in rheumatoid arthritis group and healthy group. In addition, level of serum homocysteine was correlated with resting blood flow (r = −0.41; p < 0.02) and resting vascular resistance (r = 0.31, p < 0.05) in the patients group. The study confirms altered vascular function in rheumatoid arthritis. Uniquely, the results show that homocysteine was related to resting, but not postischemia, vascular measures. These relationships indicate that homocysteine might impact the vasculature in rheumatoid arthritis.

Vascular function and handgrip strength in rheumatoid arthritis patients

OBJECTIVE

To examine the relationship of handgrip strength with forearm blood flow (BF) and vascular resistance (VR) in rheumatoid arthritis (RA) patients.

METHODS

Forearm BF at rest (RBF) and after upper arm occlusion (RHBF), and handgrip strength were examined in 78 individuals (RA = 42 and controls (CT) = 36). Subsequently, VR at rest (RVR) and after occlusion (RHVR) were calculated.

RESULTS

The patients' RBF (P = 0.02) and RHBF (P = 0.0001) were less, whereas RVR (P = 0.002) and RHVR (P = 0.0001) were greater as compared to the CTs. Similarly, handgrip strength was lower in the RAs (P = 0.0001). Finally, handgrip strength was directly associated with RBF (r = 0.43; P = 0.0001), and RHBF (r = 0.5; P = 0.0001), and inversely related to RVR (r = -0.3; P = 0.009) and RHVR (r = -0.3; P = 0.007).

CONCLUSION

The present study uniquely identifies an association between regional measures of forearm blood flow and handgrip strength in patients and healthy control. In addition, this study confirms the presence of vascular and muscle dysfunction in patients with rheumatoid arthritis, as evidenced by lower forearm blood flow indices, at rest and following occlusion, and lower handgrip strength as compared to healthy individuals.