Mitochondria are subcellular organelles involved in essential cellular functions, including cytosolic calcium regulation, cell apoptosis, and reactive oxygen species production. They are the site of important biochemical pathways, including the tricarboxylic acid cycle, parts of the ureagenesis cycle, or haem synthesis. Mitochondria are responsible for the majority of cellular ATP production through OXPHOS. Mitochondrial dysfunction has been associated with metabolic pathologies such as diabetes, obesity, hypertension, neurodegenerative diseases, cellular aging, and cancer. In this article, we describe the pathophysiological changes in, and mitochondrial role of, metabolic disorders (diabetes, obesity, and cardiovascular disease) and their correlation with oxidative stress. We highlight the genetic changes identified at the mtDNA level. Additionally, we selected several representative biomarkers involved in oxidative stress and summarize the progress of therapeutic strategies.

In recent years, research has shown that oxidative stress plays a significant role in chronic inflammatory conditions. The alteration of the oxidant/antioxidant balance leads to the appearance of free radicals, important molecules involved in both diabetes mellitus and periodontal disease. Diabetes is considered to be one of the major risk factors of periodontal disease and the inflammation characterizing this condition is associated with oxidative stress, implicitly resulting in oxidative damage to DNA. 8-Hydroxydeoxyguanosine (8-OHdG) is the most common stable product of oxidative DNA damage caused by reactive oxygen species, and its levels have been reported to increase in body fluids and tissues during inflammatory conditions. 8-OHdG emerges as a pivotal biomarker for assessing oxidative DNA damage, demonstrating its relevance across diverse health conditions, including neurodegenerative disorders, cancers, inflammatory conditions, and periodontal disease. Continued research in this field is crucial for developing more precise treatments and understanding the detailed link between oxidative stress and the progression of periodontitis. The use of the 8-OHdG biomarker in assessing and managing chronic periodontitis is an area of increased interest in dental research, with the potential to provide crucial information for diagnosis and treatment.

The diagnosis and management of fragile X syndrome (FXS) have significantly improved in the last three decades, although the current diagnostic techniques are not yet able to precisely identify the number of repeats, methylation status, level of mosaicism, and/or the presence of AGG interruptions. A high number of repeats (>200) in the fragile X messenger ribonucleoprotein 1 gene (FMR1) results in hypermethylation of promoter and gene silencing. The actual molecular diagnosis is performed using a Southern blot, TP-PCR (Triplet-Repeat PCR), MS-PCR (Methylation-Specific PCR), and MS-MLPA (Methylation-Specific MLPA) with some limitations, with multiple assays being necessary to completely characterise a patient with FXS. The actual gold standard diagnosis uses Southern blot; however, it cannot accurately characterise all cases. Optical genome mapping is a new technology that has also been developed to approach the diagnosis of fragile X syndrome. Long-range sequencing represented by PacBio and Oxford Nanopore has the potential to replace the actual diagnosis and offers a complete characterization of molecular profiles in a single test. The new technologies have improved the diagnosis of fragile X syndrome and revealed unknown aberrations, but they are a long way from being used routinely in clinical practice.

Periodontitis is a widespread inflammatory condition, characterized by a progressive deterioration of the supporting structures of the teeth. Due to the complexity of periodontal tissue and the surrounding inflammatory microenvironment, the repair of lesions at this level represents a continuous challenge. The regeneration of periodontal tissues is considered a promising strategy. Stem cells have remarkable properties, such as immunomodulatory potential, proliferation, migration, and multilineage differentiation. Thus, they can be used to repair tissue damage and reduce inflammation, potentially leading to periodontal regeneration. Among the stem cells used for periodontal regeneration, we studied dental mesenchymal stem cells (DMSCs), non-dental stem cells, and induced pluripotent stem cells (IPSCs). Although these cells have well documented important physiological characteristics, their use in contemporary practice to repair the affected periodontium is still a challenge.

Background/Objectives: Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder characterized not only by impaired carbohydrate metabolism but also by alterations in lipid and protein metabolism. Hyperglycaemia in T2DM can promote the excessive production of reactive oxygen species (ROS), leading to oxidative stress. 8-Hydroxy-2′-deoxyguanosine (8-OHdG) is a biomarker of oxidative DNA damage commonly used to investigate oxidative stress. Methods: In this cross-sectional analytical observational study, patients diagnosed with T2DM and healthy controls were enrolled. Plasma 8-OHdG concentrations were measured using an enzyme-linked immunosorbent assay (ELISA). Associations between 8-OHdG concentrations and age, fasting blood glucose, and lipid profile parameters were evaluated. These associations were further explored in patient subgroups defined according to glycated haemoglobin (HbA1c) levels. Results: Patients with T2DM had higher plasma 8-OHdG concentrations than healthy controls (Cohen’s d = 1.092; 95% CI, 0.646–1.532; p < 0.001). After adjustment for age, the between-group difference was attenuated, with an adjusted mean difference of 28.84 ng/mL (95% CI, 0.278–57.41; p = 0.048). In the overall cohort, statistically significant correlations were identified between 8-OHdG levels and age (ρ = 0.379; 95% CI, 0.164–0.556; p < 0.001), fasting blood glucose (ρ = 0.266; 95% CI, 0.059–0.474; p = 0.011), and triglycerides (ρ = 0.376, 95% CI, 0.178–0.554; p < 0.001). Stratification of patients according to HbA1c levels revealed no statistically significant differences in 8-OHdG concentrations among the subgroups. Furthermore, none of the correlations examined within these subgroups remained statistically significant after adjustment for multiple testing. Conclusions: Plasma 8-OHdG concentrations were higher in patients with T2DM than in healthy controls, although the magnitude of the between-group difference was attenuated after adjustment for age. In the overall study population, 8-OHdG concentrations were associated with age, fasting blood glucose, and triglyceride concentrations. These findings suggest that 8-OHdG levels may be associated with demographic and metabolic factors. Given the cross-sectional design, these associations should not be interpreted as causal. Further prospective studies with larger cohorts are needed to evaluate the potential clinical relevance of plasma 8-OHdG measurement in T2DM.