## 3 Oxidative Stress Biomarkers Involved in Psoriasis Inflammation
### Superoxide Dismutase (SOD)  
Superoxide dismutase (SOD) is a vital enzyme that aids in antioxidant defense inside cells. Its principal function is to catalyze the dismutation of superoxide radicals (O\({}_{2}\)\({}^{-}\)) to oxygen (O\({}_{2}\)) and hydrogen peroxide (H\({}_{2}\)O\({}_{2}\)) [49]. This enzymatic process is essential for defending cells against the damaging effects of ROS and oxidative stress. SOD exists in three main forms: cytosolic (SOD1), mitochondrial (SOD2), and extracellular (SOD3), each encoded by distinct genes [49]. SOD2, specifically found in the mitochondria, has a vital function in mitigating mtROS by converting superoxide radicals [50]. The dismutation of superoxide radicals by SOD is an important step in the antioxidant defense mechanism of cells. SOD protects cellular components such as proteins, lipids, and DNA from oxidative damage by converting superoxide radicals into less damaging molecules like oxygen and hydrogen peroxide. This mechanism is critical to maintaining cellular redox equilibrium and general health. Deficiencies or dysregulation of SOD activity, particularly SOD2, leads to increased mtROS and oxidative stress, which have been associated with various diseases and conditions, including psoriasis. Therefore, SOD plays a significant role in protecting cells from oxidative damage and maintaining their normal function and integrity. In psoriasis, where there is an imbalance between ROS production and antioxidant capacity, SOD helps to scavenge superoxide radicals and reduce oxidative stress. The observed alterations in SOD levels among individuals with psoriasis underscore the complex nature of oxidative stress in this skin condition. Several studies indicate a decrease in SOD activity, suggesting a compromised antioxidant defense system in affected individuals. This decrease in SOD levels may lead to an imbalance between ROS generation and antioxidant capacity, worsening oxidative stress and inflammation in the skin and so impacting the severity and course of psoriasis. In 2020, [PERSON] et al. noted a correlation between SOD levels and psoriasis, finding significantly lower SOD levels in psoriatic patients compared to healthy controls [51]. Similarly, [PERSON] et al. (2016) also investigated SOD levels in both psoriasis patients and controls, reporting markedly decreased SOD levels (168.46 \(\pm\) 51.89 U/mL) in psoriasis patients compared to the control group (237 \(\pm\) 39.30 U/mL) [52]. Plasma levels of SOD were evaluated in 100 psoriasis patients and 100 controls revealed a significant decrease in SOD activity (\(p\) < 0.05) among psoriasis patients, suggesting a state of oxidative stress in the disease [35]. These findings imply a potential link between diminished SOD activity and psoriasis development. However, research examining the levels of SOD in the saliva and blood of plaque psoriasis patients to healthy controls revealed considerably greater SOD concentrations in both unstimulated and stimulated saliva of psoriasis patients, suggesting redox imbalances and oxidative stress in the condition [53]. Research also found that the activity of SOD1 was notably elevated in the plasma of individuals with psoriasis [54]. Besides that, the levels of SOD1 and SOD2 genes were measured using real-time PCR, as described by [PERSON] et al. (2018). No notable disparities were detected in the manifestation of SOD1 or SOD2 genes among patients and controls, as well as across various clinical subtypes of psoriasis [55]. These investigations have shown conflicting results, with no significant decreases in SOD levels detected in psoriasis patients vs. healthy controls. These disparities might be attributable to variations in research demographics, illness severity, sample collecting procedures, or analytical methodologies. Fluctuations in SOD gene expression or enzyme activity may contribute to the disruption of cellular redox equilibrium, intensifying oxidative stress and promoting the advancement of illness.