MR-Proanp and VEGF As Markers of Response to MEL-DEX Treatment in Systemic AL Amyloidosis

The natriuretic peptides are a family of different biomarkers including NT-proBNP and MR-proANP. As recommended by guidelines, they are important in heart failure diagnosis and monitoring. MR-proANP (1–98) is the mid-regional portion of the active atrial natriuretic peptide prohormone (99–126) and is considered a significant independent predictor of death, adding prognostic value to NT-proBNP. Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen with angiogenic and nonangiogenic role in several disorders including cardiovascular ones. Moreover, it regulates multiple cellular stress responses, including survival, proliferation, migration and differentiation. Systemic AL amyloidosis represents a peculiar disease with a clinical heart involvement that needs of a specific monitoring in order to avoid poor outcome.

The study was devoted to evaluate treatment related changes in cardiovascular activity by MR-proANP and VEGF serum levels in systemic AL amyloidosis. Blood samples were collected from 8 patients with systemic AL amyloidosis (median age 72. 8 yrs) admitted to our Unit and analyzed for serum MR-proANP (mean±SD) and VEGF levels (Kits Brahms MR-proANP Kryptor and Randox Evidence Biochips Arrays). According to age and disease risk stratification all patients were treated with upfront oral Mel-Dex association (Melphalan 9 mg/sm, Dexamethasone 20mg day 1–4 q28). From each patient 2 samples of peripheral blood were performed (T0: at exordium of disease and T1: at conclusion of the first course of treatment). The sera were frozen to −80°C until their use. The results were analyzed by paired t test and Person correlation, p values ≤ 0. 05 were considered statistically significant.

VEGF serum levels were significantly (p=0. 01) reduced at the end of the first course of treatment (M±SD: T0: 282. 3 ± 86. 23 pg/mL vs. T1: 189. 7 ± 64. 24 pg/mL). Also MR-proANP serum levels were significantly decreased (M±SD: T0: 204. 4 ± 28. 82 pmol/L vs. T1: 160. 2 ± 21. 05 pmol/L, p=0. 008; see figure). The decreases of VEGF and MR-proANP were significantly (r =0. 79; p=0. 02) related.

MR-proANP serum levels reduction could be hypothized as related to the decrease of inflammatory activity of disease, including heart involvement and a consequent reduced probability of fatal events. Our hypothesis seems to be confirmed by VEGF serum level reduction suggesting an inhibition of new angiogenesis with reduced interactions between neoplastic plasma cells and bone marrow microenvironment. The effective role of treatment in reducing the disease activity is demonstrated by the significant correlation between VEGF and MR-proANP level decreases. MR-proANP and VEGF could be used to evaluate and select systemic AL amyloidosis patients with an early good response to treatment.

No relevant conflicts of interest to declare.