## 3 Results
### Blood Plasma Analysis and Blood Count  
Results of the plasma analysis (Table 1) were similar to our earlier findings in homozygous PACAP KO mice [28]. Significant changes were observed in HDL, LDL, and total cholesterol levels. However, in contrast to the earlier described slight, but not statistically significant, increases in aging PACAP KO animals, HZ mice showed significant increases in these parameters (Chol: 2.21 \(\pm\) 0.09 and 2.57 \(\pm\) 0.08 mmol/L; LDL: 0.26 \(\pm\) 0.01 and 0.37 \(\pm\) 0.02; HDL 1.86 \(\pm\) 0.08 and 2.22 \(\pm\) 0.07 in WT and HZ mice, respectively). Among the lipid parameters, no difference was observed in the TG levels. Other parameters were not altered either (creatinin, Na, K, ALP).  
\begin{table}
\begin{tabular}{c c c} \hline  & **PACAP WT Mice** & **PACAP HZ Mice** \\ \hline Creatinin (\(\mu\)mol/L) & 9.50 \(\pm\) 1.64 & 8.10 \(\pm\) 0.68 \\ Na\({}^{+}\) (mmol/L) & 160 \(\pm\) 0.5 & 157.10 \(\pm\) 0.6 \\ K\({}^{+}\) (mmol/L) & 4.13 \(\pm\) 0.09 & 4.17 \(\pm\) 0.08 \\ ALP (U/L) & 51.20 \(\pm\) 2.1 & 53.45 \(\pm\) 2.32 \\ Cholesterol (mmol/L) & 2.21 \(\pm\) 0.09 & 2.57 \(\pm\) 0.08 ** \\ TG (mmol/L) & 1.06 \(\pm\) 0.1 & 0.91 \(\pm\) 0.07 \\ LDL (mmol/L) & 0.26 \(\pm\) 0.01 & 0.37 \(\pm\) 0.02 *** \\ HDL (mmol/L) & 1.86 \(\pm\) 0.08 & 2.22 \(\pm\) 0.07 ** \\ \hline \end{tabular}
\end{table}
Table 1: Plasma analysis of wild type (WT) and PACAP heterozygous (HZ) mice. Results are given in mean \(\pm\) S.E.M. **\(p<0.01\), **\(p<0.001\) vs. WT mice.  
Figure 1: Representative photomicrographs of amyloid deposits in tissues from PAC1 receptor KO mice (**left** side) and from PACAP HZ mice (**right** side). Representative pictures from spleen, kidney, esophagus, duodenum, and skin are shown with HE staining. No amyloid deposits were found in receptor KO mice, while PACAP HZ mice showed severe deposits in the spleen parenchyma, in the renal corpuscles, in the lamina propria of esophagus and intestines, and in the subepidermal layer of the skin. Scale bar: 50 micrometers.  
Earlier, we described that the complete blood count showed no significant alterations between WT and homozygous KO mice. This is different from our present observations. We found that, while most blood count parameters did not change (Figure 3), significant changes were observed in several of them (Table 2). Among characteristic parameters of red blood cells, significant changes were observed in mean corpuscular hemoglobin concentration (MCHC), red cell distribution width--standard deviation (RDW-SD), red cell distribution width--coefficient of variation (RDW-CV), nucleated red blood cell (NRBC), reticulocyte count (RET), reticulocytes with median fluorescence (MFR), and reticulocyte hemoglobin equivalent (RET-HE). Among the platelet parameters, plateletcrit was changed. No significant differences were observed in the other measured parameters, for details see Table 2.  
Figure 3: Representative blood count results from a HZ mouse. WDF: white blood cell differential; upper (green) cloud: monocytes, lower left (purple) cloud: lymphocytes, lower middle (blue) cloud: neutroph granulocytes, lower right (red) cloud: eosinophil granulocytes. RET: reticulocytes and mature red blood cells, with the least differentiated reticulocytes in the right quartile, and mature red blood cells in the left quartile. Lower panels show representative red blood cell (RBC) and platelet (PLT) distribution width histograms.  
Figure 2: Overall amyloid index in young and aging WT and PACAP HZ mice in the most severely affected organs. Scores are represented as mean + SEM, \({}^{*}p<0.05\); \({}^{**}p<0.01\), \({}^{***}p<0.001\) compared to WT mice.