Riccardo Lacchini

This study investigated the biological mechanisms underlying temporomandibular disorder (TMD) pain in monozygotic twins discordant for the condition, isolating environmental factors from genetic influence. Twenty women (ten pairs of discordant twins) underwent standardized examinations and venous plasma analysis. Inflammatory biomarkers (IL-6, IL-10), oxidative markers (MDA, SOD, catalase), matrix remodeling proteins (MMP-2, MMP-9, TIMP-1, TIMP-2), and neurotrophic factors (BDNF, β-NGF, α2M) were measured. Twins with painful TMD demonstrated greater pain severity, functional interference, and mechanical sensitivity compared to discordant controls. Significant within-pair differences were identified in IL-6, IL-6/IL-10 ratio, MDA/SOD ratio, MMP-9, TIMP-2, and BDNF levels. Pro-inflammatory and oxidative indices positively correlated with pain intensity and palpation sensitivity, while reduced BDNF associated with greater symptom burden. Principal component analysis revealed a dominant inflammatory-oxidative profile that discriminated painful twins from controls. In genetically identical individuals, painful TMD associates with selective peripheral biological alterations involving inflammation, oxidative imbalance, and extracellular matrix remodeling. These findings could demonstrate that environmental and experiential factors biologically may contribute to vulnerability to chronic orofacial pain, highlighting the importance of epigenetic mechanisms in TMD pathogenesis beyond genetic predisposition. This article identifies specific peripheral biomarker profiles distinguishing monozygotic twins with and without painful TMD, and could show that inflammation, oxidative imbalance, matrix remodeling, and reduced neurotrophic support characterize the painful phenotype. These mechanistic insights could enable clinicians to develop targeted, biologically informed therapeutic strategies and potentially predict pain vulnerability in genetically susceptible individuals.

Introduction: Erectile dysfunction (ED) is a multifactorial condition influenced by vascular, neuroendocrine, metabolic, and psychological factors. Growing evidence suggests that genetic variation may contribute to individual susceptibility, severity, and therapeutic response, particularly regarding nitric oxide (NO) signaling and vascular pathways. To systematically synthesize evidence on genetic biomarkers associated with the risk, severity, or therapeutic response of ED in adult men. Methods: A systematic review was conducted following PRISMA 2020 guidelines and registered in PROSPERO (CRD420251144891). Searches were performed in MEDLINE, Embase, Scopus, LILACS, and Web of Science. Observational studies evaluating genetic polymorphisms or related biomarkers in adult men with Erectile dysfunction were included. Two reviewers independently screened studies, extracted data, and assessed methodological quality using JBI tools and the certainty of evidence using GRADE. Results: Thirty-five studies met inclusion criteria. The genetic markers most frequently investigated involved pathways related to nitric oxide synthesis and endothelial function, including NOS3 (eNOS), NOS1, PDE5A, VEGF, ACE, ARG1/ARG2, DDAH1/2 , and MTHFR . Functional variants—particularly NOS3 G894T, T-786C, and the intron 4 VNTR—were commonly associated with increased ED susceptibility, earlier onset, or greater severity, though results varied across populations. Several polymorphisms influenced pharmacological response to PDE5i, especially variants in PDE5A, VEGF, eNOS, ARG1/2 , and DDAH . However, methodological limitations were pervasive: 77.8% of studies had moderate risk of bias, and 80.6% showed low certainty of evidence. Only one study reached moderate certainty. Discussion/Conclusion: Current evidence suggests that genetic polymorphisms related to nitric oxide signaling, vascular regulation, and PDE5 inhibitor pharmacodynamics are associated with variability in erectile dysfunction risk and treatment response. However, the overall certainty of evidence is low, and further validation in well-designed, multiethnic studies is required before clinical translation.

Inorganic nitrite contributes to the nitrosation of biomolecules and exerts antioxidant effects. The proton pump inhibitor omeprazole has pro-oxidant effects, inhibits the formation of nitroso species in the stomach, and abrogates the blood pressure-lowering effects of orally administered nitrite. Here, we examine whether a two-week treatment with nitrite leads to tissue nitrosation that scales with local thiol concentrations and whether oral nitrite treatment can prevent the pro-oxidant effects of omeprazole. Male Sprague–Dawley rats received daily doses of omeprazole 10 mg/kg i.p. (or vehicle) and sodium nitrite 15 mg/kg by gavage (or water) for 14 days. Animals were euthanized 6 h after the last nitrite dose, and blood and tissues (brain, heart, and liver) were collected for biochemical analyses. We found that nitrite treatment increased liver nitrite and total nitroso species (RxNO) concentrations approximately eight-fold (with minor increases in other organs), and omeprazole treatment attenuated these effects. Nitrite treatment selectively elevated non-protein thiol concentrations in the liver, but not in animals also receiving omeprazole. Tissue thiol elevation was associated with increased nitrosation of hepatic proteins, which was prevented by omeprazole. Nitrite upregulated mRNA expression of microsomal glutathione S-transferase-1 (Mgst1) and decreased superoxide and hydrogen peroxide production, especially in rats co-treated with omeprazole. While omeprazole increased liver xanthine oxidoreductase (XOR), nitrite treatment attenuated this effect. These results demonstrate that oral nitrite treatment robustly elevates nitrite and RxNO concentrations in the liver, and these effects are associated with increased hepatic glutathione production and an upregulation of Mgst1 expression, counteracting the pro-oxidant effects induced by omeprazole.

Background: Psychosocial factors influence the perception of TMD signs and symptoms. Regular mindfulness practice supports their management through emotional and cognitive self‐regulation, modulating the TMD‐related pain experience. Objective: To analyse the influence of a mindfulness‐based intervention on pain, cognitions, behaviour and emotions reported by women with TMD‐related chronic pain. Methods: Eighty‐four women, aged between 18 and 61 years, with chronic TMD (diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders, DC/TMD), were randomised into an intervention group (IG) or a control group (CG). The intervention group underwent an 8‐week mindfulness practice programme, consisting of weekly 2‐h sessions and one immersion session lasting 4 h. The entire programme consisted of nine meetings. The control group did not receive any intervention during the same period. All participants underwent clinical pain assessments and completed self‐administered questionnaires before and after the intervention period. These questionnaires addressed cognitive, behavioural and emotional variables. Evaluators were blinded to the group allocations of the participants. Simple linear regression was used for the main statistical analyses, with significance established at p < 0.05. Results: Fifty‐three women completed the study (IG = 30; CG = 23). The intervention had a positive influence on the following variables: number of pain points, pain pressure threshold (PPT), stress, catastrophic thoughts and facets of mindfulness, including ‘observe’, ‘distract’, ‘non‐react’ and overall mindfulness levels (all analyses at p < 0.05). Conclusion: This unique trial, in which the mindfulness‐based intervention was compared against a control (no treatment), showed that mindfulness can contribute to the sensory, cognitive, behavioural and emotional management of pain‐related TMD. The improvement in pain, therefore, was probably influenced by the regulation of psychological aspects related to it.

Cardiovascular diseases (CVDs) are often associated with impaired nitric oxide (NO) bioavailability, a critical pathophysiological alteration in CVDs and an important target for therapeutic interventions. Recent studies have revealed the potential of inorganic nitrite and nitrate as sources of NO, offering promising alternatives for managing various cardiovascular conditions. It is now becoming clear that taking advantage of enzymatic pathways involved in nitrite reduction to NO is very relevant in new therapeutics. However, recent studies have shown that nitrite may be bioactivated in the acidic gastric environment, where nitrite generates NO and a variety of S-nitrosating compounds that result in increased circulating S-nitrosothiol concentrations and S-nitrosation of tissue pharmacological targets. Moreover, transnitrosation reactions may further nitrosate other targets, resulting in improved cardiovascular function in patients with CVDs. In this review, we comprehensively address the mechanisms and relevant effects of nitrate and nitrite-stimulated gastric S-nitrosothiol formation that may promote S-nitrosation of pharmacological targets in various CVDs. Recently identified interfering factors that may inhibit these mechanisms and prevent the beneficial responses to nitrate and nitrite therapy were also taken into consideration.

Background: Anxiety and stress are common mental health conditions reported by university workers. Practices of mindfulness represent one promising approach as an effective and feasible means to reduce stress, improve mental health and promote well-being; however, there are no clinical trials that have combined long-term stress biomarkers (hair cortisol) and psychometric assessments in a sample of university workers. Objective: This study investigated the effectiveness of a mindfulness-based program on long-term stress, by measuring hair cortisol concentration and perceived stress and anxiety among workers who were undergoing high levels of stress. Method: We conducted a randomized clinical trial at work among the employees of a public university. We compared a group that received the eight-week mindfulness intervention with the wait list group who received no intervention. Results: A total of 30 participants were included in the study, with n = 15 subjects in the intervention group and n = 15 in the control group. Hair cortisol, perceived stress and anxiety significantly reduced after the intervention compared to the control group, which had no appreciable decline in the measured variables. Conclusion: This clinical trial showed the effectiveness of a mindfulness program on mental health psychometric measures (perceived stress and anxiety) and on a long-term stress biomarker (hair cortisol). It can be concluded that an eight-week mindfulness program could be implemented as an effective strategy to reduce stress biomarkers (hair cortisol) as well as perceived stress and anxiety, improving the mental health of university workers.

Erectile dysfunction (ED) is a common male disorder, often associated with cardiovascular disease and ageing. The Sildenafil, a PDE5 inhibitor, can improve the erectile function by prolonging the nitric oxide (NO) downstream effect. NO is a molecule of pivotal importance in erection physiology and is mainly produced by neuronal nitric oxide synthase (nNOS) and endothelial NO synthase (eNOS). While it has been shown that eNOS and nNOS genetic polymorphisms could be associated with Sildenafil responsiveness in ED, no study so far has assessed whether nNOS polymorphisms and PDE5A polymorphism could be associated with increased risk to ED or with intensity of symptoms. A total of 119 ED patients and 114 controls were studied, with evaluation of the clinical disability by the International Index for Erectile Function instrument, plasma assessment of nitrite levels and genomic DNA analysis regarding the rs41279104 and rs2682826 polymorphisms of the NOS1 gene and the rs2389866, rs3733526 and rs13124532 polymorphisms of the PDE5A gene. We have found a significant association of the rs2682826 with lower IIEF scores in the clinical ED group. While this result should be confirmed in other populations, it may be helpful in establishing a genetic panel to better assess disease risk and prognosis on ED therapy.

Lower HMW (high molecular weight) adiponectin levels are associated with obesity, insulin resistance, and metabolic syndrome in children and adolescents. However, data on HMW levels in pediatric population with hypertension are lacking. This study aimed to examine the association and predictive capacity of HMW levels, HMW/HOMA-IR, and HMW/APN ratio with hypertension in obese children and adolescents. The 299 pediatric subjects were grouped in obese hypertensive (OH), obese normotensive (ON), and normal weight normotensive (NN). Plasma concentrations of HMW were investigated by ELISA. ANOVA was used to compare study groups, and a binary logistic regression analysis was used to verify if HMW, HMW/HOMA-IR, HMW/APN, APN, APN/HOMA-IR, and HOMA-IR are associated to hypertension regardless obesity in children and adolescents. To compare the strength and performance of each biomarker to classify individuals with and without hypertension, the receiver-operating characteristic (ROC) curve, area under the curve (AUC), and Youden index (J) were evaluated. Both HMW plasma levels and the HMW/HOMA-IR ratio were significantly lower in the OH group when compared to the ON group (HMW: 2.00 ± 1.33 µg/mL vs 2.48 ± 1.48 µg/mL; HMW/HOMA-IR ratio: 0.87 ± 0.95 vs 1.27 ± 1.2; P < 0.05) and NN weight groups (HMW: 2.00 ± 1.33 µg/mL vs 4.02 ± 1.99 µg/mL; HMW/HOMA-IR ratio: 0.87 ± 0.95 vs 2.62 ± 1.86; P < 0.05). Hypertension was associated with lowest HMW (OR = 4.50; 95% CI = 1.41–15.84) and HMW/HOMA-IR (OR = 12.13; 95% CI = 2.51–92.93) regardless of obesity. However, HOMA-IR or the HMW/APN was not significant (P > 0.05). In the ROC curve analyses, the HMW and HMW/HOM-IR were more sensitive to detect hypertension in children and adolescents with obesity. Conclusion: Low levels of HMW oligomer and HMW/HOM-IR are associated with hypertension in childhood obesity. Thus, these biomarkers could be clinically useful in identifying hypertension in childhood obesity. What is Known: • HMW has previously been reported as the most biologically active isoform of adiponectin, and lower HMW concentrations are associated with obesity, insulin resistance, and metabolic syndrome in children and adolescents. • HMW/HOMA-IR ratio is a sensitive predictor for metabolic syndrome in adults. What is New: • HMW levels are associated with hypertension in children and adolescents, independently of presence of obesity. • HMW was more sensitive to detect hypertension in children and adolescents with obesity when compared to HMW/HOMA-IR, HMW/APN, APN, APN/HOMA-IR, or HOMA-IR.

Objectives: Gene-environment interactions increase the risk of psychosis. The objective of this study was to investigate gene-gene and gene-environment interactions in psychosis, including single nucleotide variants (SNVs) of dopamine-2 receptor (D2R), N-methyl-d-aspartate receptor (NMDAR), and cannabinoid receptor type 1 (CB1R), lifetime cannabis use, and childhood trauma.Methods: Twenty-three SNVs of genes encoding D2R (DRD2: rs1799978, rs7131056, rs6275), NMDAR (GRIN1: rs4880213, rs11146020; GRIN2A: rs1420040, rs11866328; GRIN2B: rs890, rs2098469, rs7298664), and CB1R (CNR1: rs806380, rs806379, rs1049353, rs6454674, rs1535255, rs2023239, rs12720071, rs6928499, rs806374, rs7766029, rs806378, rs10485170, rs9450898) were genotyped in 143 first-episode psychosis patients (FEPp) and 286 communitybased controls by Illumina HumanCoreExome-24 BeadChip. Gene-gene and gene-environment associations were assessed using nonparametric Multifactor Dimensionality Reduction software.Results: Single-locus analyses among the 23 SNVs for psychosis and gene-gene interactions were not significant (p 4 0.05 for all comparisons); however, both environmental risk factors showed an association with psychosis (p < 0.001). Moreover, gene-environment interactions were significant for an SNV in CNR1 and cannabis use. The best-performing model was the combination of CNR1 rs12720071 and lifetime cannabis use (p < 0.001), suggesting an increased risk of psychosis.Conclusion: Our study supports the hypothesis of gene-environment interactions for psychosis involving T-allele carriers of CNR1 SNVs, childhood trauma, and cannabis use.