## 4 Oxidative Stress Parameters Involved in Psoriasis Inflammation
### Malondialdehydedehyde (MDA)  
Malondialdehydedehyde (MDA) is a reactive aldehyde compound generated as a byproduct of lipid peroxidation, a process initiated when free radicals attack unsaturated fatty acids within cell membranes [63]. Widely recognized as a marker of oxidative stress, MDA levels serve as indicators of oxidative damage in biological systems. Elevated MDA levels signify increased lipid peroxidation and oxidative stress, processes implicated in the pathophysiology of various disorders, including inflammatory skin conditions like psoriasis [64]. In studies involving psoriasis patients, elevated MDA levels have been consistently observed, indicating heightened oxidative stress in this population [47; 65]. In a study conducted by [PERSON] et al., 150 psoriasis patients and 150 healthy controls had their serum lipids, lipoproteins, and antioxidant-oxidant status assessed. The findings revealed that the psoriasis patients had significantly higher levels of lipid peroxidation products, such as MDA [66]. In addition, 23 psoriasis patients and 23 healthy people had their levelsof MDA analyzed and the findings indicated that the MDA levels in the psoriasis patients were considerably greater than those in the control group [65].  
Furthermore, MDA levels have been linked to disease severity and duration in psoriasis patients, suggesting a potential role in disease progression. Fifty psoriasis patients participated in research where their MDA levels were measured [67]. The findings showed that psoriatic patients had much higher MDA levels than controls, and there were positive associations found between MDA levels and the length and severity of the illness [67]. Measurement of MDA levels in biological samples such as blood, urine, and tissues provides valuable insights into oxidative stress status and disease monitoring. A study compared the blood and saliva of patients with plaque psoriasis to healthy controls in order to assess redox balance parameters and indicators of oxidative stress in both stimulated and nonstimulated saliva [53]. MDA concentrations in psoriatic patients' samples were considerably higher than in controls, suggesting that patients with plaque psoriasis have greater levels of oxidative stress [53]. According to these results, MDA concentration in saliva may be used as a biomarker for plaque psoriasis diagnosis. According to [PERSON] et al.'s study, tissue levels of MDA in lesional skin were significantly higher than in non-lesional skin, indicating a role for increased oxidative stress in the etiology of psoriasis [65].  
Overall, elevated MDA levels indicate heightened oxidative damage and the need for antioxidant intervention. Monitoring MDA levels offers insights into the degree of oxidative stress and its impact on skin diseases like psoriasis. Beyond serving as oxidative stress markers, MDA actively participates in cellular dysfunction and disease pathogenesis by forming adducts with proteins and DNA, thereby contributing to tissue damage, inflammation, and disruption of vital cellular processes. Understanding the role of MDA in psoriasis pathophysiology provides avenues for targeted therapeutic interventions aimed at mitigating oxidative stress and improving patient outcomes.  
Figure 2: Overview of oxidative stress parameters in psoriasis inflammation. This figure provides a summary of key oxidative stress parameters associated with psoriasis. It depicts the roles of malondialdehydedehyde (MDA), total antioxidant status (TAS), oxidative stress index (OSI), and total oxidant status (TOS) in evaluating oxidative stress and antioxidant defense mechanisms in psoriasis patients.