Table 2.

Studies exploring the predictive capacity of biomarkers of protein peroxidation in AD.

Reference	Subjects' characteristic	Specimen	Results
Protein carbonyls
Cristalli et al. (2012) [7]	110 AD pts (mean age = 74.7, GDS 3 = mild, GDS 4-5 = intermediate, GDS 6-7 = severe). No further exclusion criteria. 134 controls (mean age = 77.8).	plasma/ erythrocyte/ leukocytes	Significantly higher in mild, intermediate, and severe AD in comparison with control in plasma, erythrocytes, and leukocytes samples. Significantly higher in severe AD than intermediate AD and in intermediate AD than mild AD in plasma, erythrocytes, and leukocytes samples. Inversely correlated with MMSE in all kind of samples.
Bermejo et al. (2008) [41]	45 AD pts. 28 controls.	Serum	Significantly higher in AD (P < 0.05).
Conrad et al. (2000) [42]	25 AD pts (mean age = 78). 14 controls (mean age = 84).	Serum (HPLC)	Significantly higher in AD (P < 0.05).
Aldred et al. (2010) [17]	72 AD pts (mean age = 80, AD GDS = 7.4 ± 3.6, MMSE = 19 ± 4).72 controls (mean age = 75).	Serum	No significant difference between AD and NC.
Cai et al. (2007) [40]	15 AD pts. 15 controls.	Serum	Significantly higher in AD (P < 0.05). MMSE inversely correlated with ox-LDL (P < 0.05).
Puertas et al. (2012) [28]	20 AD men (mean age = 70.6, MMSE 23.7 ± 0.92). 26 AD women (mean age = 73.9, MMSE 20.7 ± 0.66). Exclusion criteria: taking NSAIDs, steroids, vitamins or antioxidant supplements, history of smoking and alcohol intake, and comorbidity with other clinical major neurological illnesses. 16 control men (mean age = 73.3. 30 control women (mean age = 73.8).	Plasma	Significantly higher in both male and female AD individuals in serum level (P < 0.05).
Sultana et al. (2006) [43]	6 AD pts (mean age at death = 84.5, MMSE = 15.7 ± 2.6). 6 controls (mean age at death = 85.8)	Brain: hippocampus	All identified proteins with protein carbonyls significantly higher in AD (P ≤ 0.05).
Castegna et al. (2002) [47]	5 AD pts (mean age at death = 85. 5). 5 controls (mean age at death = 83).	Brain: neocortical, hippocampal, entorhinal, amygdala, brainstem, and cerebellum	All identified proteins with protein carbonyls significantly higher in AD (P ≤ 0.05).
Korolainen and Pirttilä (2009) [18]	22 AD pts (mean age = 72, 22 AD pts disease duration = 2.3 ± 0.3, MMSE = 21.3 ± 0.9, 12 AD pts APOE4 positive). 10 control APOE4 positive. 18 controls (mean age = 68).	CSF/ plasma/ serum	Significantly higher in all APOE4 negative subjects (P = 0.03) and APOE4 negative control (P = 0.016) in CSF specimen. Significantly higher in all control subjects than AD in serum (P = 0.005). No significant difference in plasma.
Choi et al. (2002) [44]	9 AD pts (age of 70 to 89). 9 controls (age of 74 to 89).	plasma	Significantly higher protein carbonyl in AD (P < 0.05).
Korolainen et al. (2007) [45]	11 AD pts (mean age = 73.5, mild AD MMSE of 14 to 26). 8 controls (mean age = 64.6)	CSF	Significantly higher carbonation of λ chain precursor in AD (P = 0.03).
Ahmed et al. (2005) [46]	32 AD pts (mean age = 71). All before treatment of AchEI. 18 controls (mean age = 69).	CSF	Significantly higher oxidized NFK and DG-H in AD (P < 0.05).
Aksenov et al. (2001) [14]	6 AD pts (mean age = 80.4). 6 controls (mean age = 81.1).	Brain: hippocampus, superior and middle temporal lobe	Significantly higher carbonated CKBB and β-actin in AD (P < 0.05).
Nitrated protein
Korolainen and Pirttilä (2009) [18]	22 AD pts (mean age = 72, 22 AD pts disease duration = 2.3 ± 0.3, MMSE = 21.3 ± 0.9, 12 AD pts APOE4 positive). 10 control APOE4 positive. 18 controls (mean age = 68).	CSF/ plasma/ serum	No significant difference in CSF, plasma, serum.
Sultana et al. (2006) [43]	6 AD pts (mean age = 84.5). 6 controls (mean age = 85.8).	Brain: hippocampus	All identified proteins with nitrated protein significantly higher in AD (P ≤ 0.05).
Tohgi et al. (1999) [48]	25 AD pts (mean age = 67.9, 25 AD pts disease duration = 3.9 ± 2.1, MMSE = 15.6 ± 5.0. 24 controls.	CSF	Significantly higher nitrated protein in AD (P = 0.0001). CSF nitrated protein inversely correlated with MMSE.
Castegna et al. (2003) [19]	5 AD pts (mean age at death = 85. 5). 5 controls (mean age at death = 83).	Brain: inferior parietal lobe	A-Enolase, Triosephosphate isomerase, and neuropolypeptide h3 nitration significantly higher in AD (P ≤ 0.05).
Hensley et al. (1998) [49]	11 AD pts (mean age at death = 78.5). controls (mean age at death = 78).	Brain: hippocampus, inferior parietal lobe, superior and middle temporal lobe, cerebellum.	Nitrated protein significantly in AD in area of hippocampus, inferior parietal lobe, superior and middle temporal lobe (P < 0.05).
Ahmed et al. (2005) [46]	32 AD pts (mean age = 71, all before treatment of AchEI). 18 controls (mean age = 69).	CSF	Significantly higher nitrated protein in AD (P < 0.05).
Ryberg et al. (2004) [50]	17 AD pts (mean age = 73.4, mild AD pts MMSE of 19 to 24, moderate AD pts MMSE of 12 to 18, severe AD pts MMSE of 0 to 12. 19 controls (mean age = 68).	CSF	No difference of nitrated protein between AD and control.