VIP and cardiovascular disorder: The phenylalanine concentration was also increased in the patient vs. control serums in this study (Figure 2 and Figure 3) with VIP > 2 (Figure 1b), which is also in accordance with related studies in which it was associated with ischemic stroke and cardiovascular diseases [35] and also suggested to be a compensatory response to high neurotoxic concentrations of glutamate because of phenylalanine inhibition of excitatory glutamatergic synaptic transmission [16].