An elevated level of serum uric acid—hyperuricemia, is strongly associated with the development of gout and chronic kidney disease (CKD) which is often accompanied by a significantly reduced glomerular filtration rate (GFR). In the present study, we investigated the extra-renal elimination of uric acid via the intestine in a healthy pig model and the effect of oral uricase therapy on plasma uric acid concentrations in pigs with induced hyperuricemia and CKD. The experiment was conducted on eleven, ten-week-old pigs (n = 11). The porcine model of CKD was developed by performing 9/10 nephrectomy surgery on eight pigs. A stable model of hyperuricemia was established in only five of the eight nephrectomized pigs by frequent injections of uric acid (UA) into the jugular vein. All pigs (three healthy pigs and five CKD pigs) were operated for implantation of jugular vein catheters and the three healthy pigs also had portal vein catheters inserted. Blood uric acid concentrations were measured spectrophotometrically, using the Uric Acid Assay Kit (BioAssay Systems, Hayward, USA). The piglets with CKD received orally administered uricase (treatment) and served as their own controls (without uricase supplementation). Oral uricase therapy significantly decreased plasma uric acid concentrations in pigs with CKD, whereas hyperuricemia was observed in the pigs whilst not being treated with uricase. Urinary uric acid excretion was similar during both the treatment and control periods during the first 8 h and 24 h after UA infusions in the CKD pigs. To demonstrate the elimination of UA via the intestine, the healthy pigs were infused with UA into the jugular vein. The blood collected from the jugular vein represents circulating UA concentrations and the blood collected from the portal vein represents the concentration of UA leaving the intestine. The final (after 2 h) concentration of UA was significantly lower in blood collected from the portal vein compared to that collected from the jugular vein (3.34 vs. 2.43 mg/dL, respectively, p = 0.024). The latter allows us to suggest that UA is eliminated from the blood via the gut tissue.

The oral cavity is a unique environment that consists of teeth surrounded by periodontal tissues, oral mucosae with minor salivary glands, and terminal parts of major salivary glands that open into the oral cavity. The cavity is constantly exposed to viral and microbial pathogens. Recent studies indicate that components of the plasminogen (Plg)/plasmin (Pm) system are expressed in tissues of the oral cavity, such as the salivary gland, and contribute to microbial infection and inflammation, such as periodontitis. The Plg/Pm system fulfills two major functions: (a) the destruction of fibrin deposits in the bloodstream or damaged tissues, a process called fibrinolysis, and (b) non-fibrinolytic actions that include the proteolytic modulation of proteins. One can observe both functions during inflammation. The virus that causes the coronavirus disease 2019 (COVID-19) exploits the fibrinolytic and non-fibrinolytic functions of the Plg/Pm system in the oral cavity. During COVID-19, well-established coagulopathy with the development of microthrombi requires constant activation of the fibrinolytic function. Furthermore, viral entry is modulated by receptors such as TMPRSS2, which is necessary in the oral cavity, leading to a derailed immune response that peaks in cytokine storm syndrome. This paper outlines the significance of the Plg/Pm system for infectious and inflammatory diseases that start in the oral cavity.

Periodontitis is a chronic inflammatory condition that gradually destroys the tissues supporting the teeth, including the gingiva, periodontal ligament, and alveolar bone. Emerging evidence suggests that psychological stress plays a significant role in the initiation and progression of periodontal disease, primarily through its impact on immune regulation. Stressors activate the hypothalamic–pituitary–adrenal (HPA) axis, leading to the release of corticotropin-releasing hormone (CRH) from the hypothalamus and, in turn, adrenocorticotropic hormone (ACTH) from the pituitary gland. Activation of the HPA axis and the sympathetic-adrenal-medullary (SAM) system during stress triggers the systemic release of cortisol, epinephrine, norepinephrine, and cytokines. The HPA, SAM, and cytokines interact in both direct and indirect ways. Not only does stress induce interleukin-10 (IL-10), but IL-10 also helps regulate the stress response and cortisol levels. IL-10 can stimulate the release of CRH and ACTH, while concurrently inhibiting cortisol secretion from the adrenal glands. IL-10 has drawn increasing attention within the oral cavity owing to its dual role in modulating immune responses and maintaining periodontal tissue homeostasis. This review outlines the current understanding of stress-related neuroendocrine pathways and their relevance to periodontal health. It explores the involvement of HPA axis effectors—cortisol and IL-10—in modulating the inflammatory milieu associated with periodontitis. This includes recent insights into IL-10-expressing regulatory B cells and the potential role of IL-10 in mitigating alveolar bone loss. By integrating recent advances in neuroendocrinology, immunology, and oral biology, this review clarifies how systemic stress responses contribute to local inflammatory changes in the periodontium. Understanding the mechanisms linking psychological stress, cortisol dynamics, and IL-10-mediated regulation may offer new opportunities for early diagnosis and intervention in stress-exacerbated periodontitis.

Patients with coronavirus disease-2019 (COVID-19) have an increased risk of thrombosis and acute respiratory distress syndrome (ARDS). Thrombosis is often attributed to increases in plasminogen activator inhibitor-1 (PAI-1) and a shut-down of fibrinolysis (blood clot dissolution). Decreased urokinase-type plasminogen activator (uPA), a protease necessary for cell-associated plasmin generation, and increased tissue-type plasminogen activator (tPA) and PAI-1 levels have been reported in COVID-19 patients. Because these factors can occur in free and complexed forms with differences in their biological functions, we examined the predictive impact of uPA, tPA, and PAI-1 in their free forms and complexes as a biomarker for COVID-19 severity and the development of ARDS. In this retrospective study of 69 Japanese adults hospitalized with COVID-19 and 20 healthy donors, we found elevated free, non-complexed PAI-1 antigen, low circulating uPA, and uPA/PAI-1 but not tPA/PAI-1 complex levels to be associated with COVID-19 severity and ARDS development. This biomarker profile was typical for patients in the complicated phase. Lack of PAI-1 activity in circulation despite free, non-complexed PAI-1 protein and plasmin/α2anti-plasmin complex correlated with suPAR and sVCAM levels, markers indicating endothelial dysfunction. Furthermore, uPA/PAI-1 complex levels positively correlated with TNFα, a cytokine reported to trigger inflammatory cell death and tissue damage. Those levels also positively correlated with lymphopenia and the pro-inflammatory factors interleukin1β (IL1β), IL6, and C-reactive protein, markers associated with the anti-viral inflammatory response. These findings argue for using uPA and uPA/PAI-1 as novel biomarkers to detect patients at risk of developing severe COVID-19, including ARDS.

Treatment resistance after chemo-/immunotherapy occurs in patients with head and neck squamous cell cancers (HNSCs), including salivary gland cancers (SGCs). Interleukin-10 (IL-10), a cytokine with pro- and anti-cancer effects, has an unclear impact on HNSC/SGC cells. We show that HNSC patients exhibiting high expression of IL-10 and its receptor IL-10Rα experience have prolonged overall survival. Immunoreactive IL-10 was low in ductal cells of human SGC biopsies. Human (A253) and murine WR21-SGC cells expressed IL-10Rβ, but only A253 cells expressed IL-10 and IL-10Rα. The addition of recombinant IL-10 impaired SGC cell proliferation and induced apoptosis in vitro. N-acetylcysteine restored IL-10-induced reactive oxygen species (ROS) production but did not prevent IL-10-mediated viability loss. Mechanistically, recIL-10 delayed cell cycle progression from G0/G1 to the S phase with cyclin D downregulation and upregulation of NF-kB. IL-10 increased tumor necrosis factor-α (TNF-α) in A253 and WR21 and FasL in WR21 cells. Neutralizing antibodies against TNF-α and NF-kB inhibition restored SGC proliferation after IL-10 treatment, emphasizing the critical role of TNF-α and NF-kB in IL-10-mediated anti-tumor effects. These findings underscore the potential of IL-10 to impede SGC cell growth through apoptosis induction, unraveling potential therapeutic targets for intervention in salivary gland carcinomas.

During pregnancy, the maternal hemostatic system undergoes significant changes to support placental angiogenesis, maintain fetal blood flow, and ensure safe delivery. This study investigates the dysregulation of hemostasis in placental insufficiency and explores potential markers for diagnosing and managing this gestational complication. Thromboelastography, coagulation and fibrinolysis functional assays, ELISA, and immunoblotting were employed to assess hemostasis dysregulation in placental dysfunction of two cohorts of pregnant women with placental dysfunction and healthy controls. Thromboelastographic analysis revealed no significant differences in clot lysis indices between the control and placental dysfunction groups, with values remaining within normal ranges, suggesting this method’s limitations for assessing fibrinolysis in pregnancy. The placental dysfunction group demonstrated moderately increased fibrinogen levels and platelet sensitivity to ADP, indicating hemostasis reactiveness. Significantly lower D-dimer levels, decreased plasminogen activator inhibitor activity (total PAI-1 + PAI-2), and increased plasminogen activator activity, driven primarily by uPA in the placental dysfunction group, indicated abnormal fibrinolysis. Immunoblotting confirmed elevated uPA/uPA-PAI complexes and reduced tPA/tPA-PAI complexes, indicating that shutdown of tPA-mediated fibrinolysis and induction of uPA-driven vessel-wall-associated proteolysis are linked to placental dysfunction. Placental dysfunction involves fibrinolytic system dysregulation, marked by decreased PAI and tPA, uPA overproduction, and hypofibrinolysis, contributing to thrombotic risks, impaired placental flow, and complications like fetal growth retardation. PAI/PA ratio and D-dimer levels have diagnostic potential for placental-dysfunction-associated complications.