Anales de la RANM

61 A N A L E S R A N M R E V I S T A F U N D A D A E N 1 8 7 9 SERUM MYELOPEROXIDASE AND PARKINSON´S DISEASE Fernández-Espejo E An RANM. 2022;139(01): 56 - 66 3.2. DAT-SPECT parameters Regarding DAT-SPECT, all striatal regions (the putamen and the caudate nucleus) showed loss of nigrostriatal dopaminergic neuronal terminals in the cohort of patients, as quantified through percentage reduction of SBR or %rSBR (Table 2). The absolute value of specific binding ratio (SBR) was significantly lower in the left and right putamen versus right and left caudate nucleus, respectively (right, t=7.4626; left, t=9.1306, p<.0001; Table 2). Percentage reduction of SBR (%rSBR) was found to be significantly higher in the left and right putamen relative to the right and left caudate nucleus, respectively (right, t=4.2726; left, t=5.4527, p<.0001; Table 2). Individual values of specific binding ratio of 123 I-Ioflupane on basal ganglia, and percent reduction of DAT binding in patients with idiopathic Parkinson’s disease are available upon request. 3.3. Correlation of serum and CSF myelope- roxidase concentration with demographic, clinical and DAT-SPECT parameters Significant correlations were found between serum MPO concentration and the rating scales Hoehn- Yahr staging (p=.0003) and motor MDS-UPDRS part III (p=.005), as well as percentage reduction of SBR or %rSBR on basal ganglia (p<.001), as shown in Table 3 and Figure 2. PD patients were divided into two subgroups according to disease severity: early disease, Hoehn-Yahr stages 1 and 2, n=25; and moderate-advanced disease, Hoehn-Yahr stage 3, n=11 (no patients at stages 4 or 5). Statistical comparisons revealed that serum MPO concentra- tion was significantly higher in both PD subgroups than in controls (early disease, t=4.496, p<.0001; moderate-advanced disease, t=8.0719, p<.0001), and that patients with moderate-advanced disease showed significantly higher serum MPO content relative to patients with early disease (t=4.1533, p=.0002), as shown in Table 1 and Figure 1B. Taken together, the results indicate that serum MPO content is related to degree of motor severity of PD. Finally, no significant correlation was found between serum MPO concentration and CSF MPO content (patients, r= -.202; controls, r= -.168, NS; Table 1), indicating that both parameters are independent to each other. Regarding DAT-SPECT data, percentage reduction of DAT binding on the striatum and putamen positively correlated with rating scales of motor severity (right and left striatum, and right and left Table 2.- DAT-SPECT parameters in the cohort of patients with idiopathic Parkinson´s disease SBR P Right striatum 2.4998±0.5202 Left striatum 2.5517±0.5491 Right caudate nucleus 3.0131±0.7608 <.0001 vs. right putamen Left caudate nucleus 3.3149±0.5928 <.0001 vs. left putamen Right putamen 1.9528±0.3846 Left putamen 2.1696±0.4637 %rSBR Right striatum 45.2±15.3 Left striatum 43.9±15.1 Right caudate nucleus 29.7±26.8 <.0001 vs. right putamen Left caudate nucleus 26.6±21.8 <.0001 vs. left putamen Right putamen 52.9±16.2 Left putamen 50.7±15.1 Mean ± SD. Statistical comparisons were carried out with the Student’s t test, and Bonferroni correction of significance. Ab- brev.: DAT-SPECT, Dopamine-transporter Single Photon Emission Computed Tomography; P, two-tailed probability value; SBR, specific binding ratio; %rSBR, percentage reduction of SBR.