Intravenous magnesium for chronic complex regional pain syndrome type 1 (CRPS-1).

OBJECTIVE: To assess the effects of intravenous administration of magnesium on complex regional pain syndrome type 1 (CRPS-1), a randomized double-blind placebo-controlled trial was performed. METHODS: Fifty-six patients with CRPS-1 (International Association for the Study of Pain Orlando criteria) received MgSO(4) 70 mg/kg or placebo (NaCl 0.9%) in 4 hours over 5 consecutive days. Pain (BOX-11 and McGill), the level of impairment (Impairment level Sum Score [ISS]), functional limitations (Radboud Skills Questionnaire, Walking Skills Questionnaire/questionnaire rising and sitting down), participation (Impact on Participation and Autonomy [IPA]), and quality of life (Short Form-36, EuroQol, IPA) were evaluated at baseline and at 1, 3, 6, and 12 weeks. RESULTS: No significant differences were found between MgSO(4) and placebo on the BOX-11 and ISS at different time points during the trial on intention-to-treat and per-protocol analysis. A significant improvement on the BOX-11 was found after the first week of the trial in both groups (mean 0.7; standard deviation 1.1). For the MgSO(4) group, a clinically relevant and statistically significant improvement on the ISS at 1 week (median 5, interquartile range [IQR] -1 to 8) and a significant improvement on the McGill up to 6 weeks (median 2 words, IQR 0-4.5) were found compared with baseline, which were not found in the placebo group. Significant improvement in perceived job participation was found for the MgSO(4) group at 12 weeks (median improvement 1.44-1.17; P = 0.01). ISS improved significantly more in patients with a low Hospital Anxiety and Depression Scale (HADS) score (≤10) in the MgSO(4) group (mean 4.4 vs mean -3.1; P = 0.02). CONCLUSION: Administration of the physiological competitive N-methyl-D-aspartate receptor antagonist magnesium in chronic CRPS provides insufficient benefit over placebo. Future research should focus on patients with acute CRPS and early signs and symptoms of central sensitization.

Oxidative stress in Complex Regional Pain Syndrome (CRPS): no systemically elevated levels of malondialdehyde, F2-isoprostanes and 8OHdG in a selected sample of patients.

Exaggerated inflammation and oxidative stress are involved in the pathogenesis of Complex Regional Pain Syndrome (CRPS). However, studies assessing markers for oxidative stress in CRPS patients are limited. In this study, markers for lipid peroxidation (malondialdehyde and F2-isoprostanes) and DNA damage (8-hydroxy-2-deoxyguanosine) were measured in nine patients (mean age 50.1 ± 17.1 years) with short term CRPS-1 (median 3 months) and nine age and sex matched healthy volunteers (mean age 49.3 ± 16.8 years) to assess and compare the level of oxidative stress. No differences were found in plasma between CRPS patients and healthy volunteers for malondialdehyde (5.2 ± 0.9 µmol/L vs. 5.4 ± 0.5 µmol/L) F2-isoprostanes (83.9 ± 18.7 pg/mL vs. 80.5 ± 12.3 pg/mL) and 8-hydroxy-2-deoxyguanosine (92.6 ± 25.5 pmol/L vs. 86.9 ± 19.0 pmol/L). Likewise, in urine, no differences were observed between CRPS patients and healthy volunteers for F2-isoprostanes (117 ng/mmol, IQR 54.5-124.3 vs. 85 ng/mmol, IQR 55.5-110) and 8-hydroxy-2-deoxyguanosine (1.4 ± 0.7 nmol/mmol vs. 1.4 ± 0.5 nmol/mmol). Our data show no elevation of systemic markers of oxidative stress in CRPS patients compared to matched healthy volunteers. Future research should focus on local sampling methods of oxidative stress with adequate patient selection based on CRPS phenotype and lifestyle.

Nuchal edema and venous-lymphatic phenotype disturbance in human fetuses and mouse embryos with aneuploidy.

OBJECTIVE: Nuchal edema (NE) is a clinical indicator for aneuploidy, cardiovascular anomalies, and several genetic syndromes. Its etiology, however, is unknown. In the nuchal area, the endothelium of the jugular lymphatic sacs (JLS) develops by budding from the blood vascular endothelium of the cardinal veins. Abnormal distension of the jugular sacs is associated with NE. We hypothesize that a disturbed lymphatic endothelial differentiation and sac formation causes NE. We investigated endothelial differentiation of the jugular lymphatic system in human and mouse species with NE. METHODS: Aneuploid human fetuses (trisomy 21; trisomy 18) were compared with euploid controls (gestational age 12 to 18 weeks). Trisomy 16 mouse embryos were compared with wild type controls (embryonic day 10 to 18). Trisomy 16 mice are considered an animal model for human trisomy 21. Endothelial differentiation was investigated by immunohistochemistry using lymphatic markers (prox-1, podoplanin, lymphatic vessel endothelial hyaluronan receptor [LYVE]-1) and en blood vessel markers (neuropilin [NP]-1 and ligand vascular endothelial growth factor [VEGF]-A). Smooth muscle actin (SMA) was included as a smooth muscle cell marker. RESULTS: We report a disturbed venous-lymphatic phenotype in aneuploid human fetuses and mouse embryos with enlarged jugular sacs and NE. Our results show absent or diminished expression of the lymphatic markers Prox-1 and podoplanin in the enlarged jugular sac, while LYVE-1 expression was normal. Additionally, the enlarged JLS showed blood vessel characteristics, including increased NP-1 and VEGF-A expression. The lumen contained blood cells and smooth muscle cells lined the wall. CONCLUSION: A loss of lymphatic identity seems to be the underlying cause for clinical NE. Also, abnormal endothelial differentiation provides a link to the cardiovascular anomalies associated with NE.