For decades, neurologic and other extra glandular manifestations have been described in Sjögren’s syndrome (SS). More recently, neuropathic, psychological and cognitive alterations are being considered part of the disease. The lacrimal glands (LG), the ocular surface (OS), salivary glands (SG) and the central nervous system (CNS) are integrated to modulate the autonomic functions and, not just those organs, but also the hippocampus, which is linked to the autonomic nervous system, and modulate behavior responses appears to be compromised in the SS. Recent studies confirm that the tryptophan/kynurenine pathway (TKP) can be stimulated by interferon-γ (IFN-γ) and other cytokines, activating the indoleamine-pyrrole 2,3-dioxygenase (IDO) in SS. This pathway interferes on serotonergic and glutamatergic neurotransmission, mostly in the hippocampus, and other structures of the CNS. Although not demonstrated, it is plausible that this constant interference induces clinical signs of SS, and contributes to the discrepancy between symptoms and signs, towards manifestations of hyperalgesia and depression in patients with SS. Therapeutic strategies are being reexamined and new options designed and tested to regulate the involved steps of the TKP. In the future, the application of this concept may offer a clue to the mosaic of manifestations of SS.

Major Depression Disorder (MDD) is accompanied by an immune response characterized by increased levels of pro-inflammatory and immune-regulatory cytokines and cytokine-induced stimulation of indoleamine-2,3-dioxygenase (IDO). There is also some evidence that anti-inflammatory drugs may have a clinical efficacy in MDD.The aim of this study is to examine the clinical effects of an eight-week combinatorial treatment of ketoprofen (a nonsteroidal anti-inflammatory drug) combined or not with sertraline, on serum levels of IDO, interferon (IFN)-γ, interleukin (IL)-4 and transforming growth factor (TGF)-β1 in association with changes in the Beck-Depression Inventory-II (BDI-II). The study included 140 MDD patients and 40 normal controls. The pre-treatment serum levels of IDO, IFN-γ, TGF-β1 and IL-4 were significantly higher in MDD patients compared with the control group. Treatment with sertraline with or without ketoprofen significantly reduced the increased baseline production of all 4 biomarkers to levels which were similar as those of normal controls. Ketoprofen add-on had a significantly greater effect on IDO and BDI-II as compared with placebo. The reductions in IDO, IL-4 and TGF-β1 during treatment were significantly associated with those in the BDI-II.In conclusion, the clinical efficacy of both sertraline + ketoprofen may be ascribed at least in part to attenuated IDO levels and immune-inflammatory responses in MDD. Moreover, add-on treatment with ketoprofen may augment the efficacy of sertraline by attenuating IDO. However, these treatments may also significantly reduce the more beneficial properties of T helper-2 and T regulatory (Treg) immune subsets. Future research should develop immune treatments that target the immune-inflammatory response in MDD, while enhancing the compensatory immune-regulatory system (CIRS).

“All diseases originate in the gut.” Hippocrates (400 BC) A healthy gut microbiome via the gut-brain-axis (GBA) elevates heart rate variability (HRV), a general measure of health and well-being. A dysbiotic gut microbiome, low in biodiversity and butyrate producers, alters tryptophan metabolism with release of proinflammatory cytokines, predominantly TNF-α, IL-6, and IL-1β. These also characterize chronic inflammation, oxidative stress, and a multitude of diseases, all exhibiting low HRV. Gut dysbiosis upregulates IFN-γ and with it IDO (indoleamine 2,3 dioxygenase). Tryptophan pivots from serotonin synthesis to that of IDO induced kynurenine, increasing the kynurenine to tryptophan ratio (KTR). An elevated KTR is positively linked to neurodegenerative and autoimmune diseases and negatively linked to HRV. Elevated IDO activity is not only enzymatic but also an intracellular signal transducer potentiated by TGF-β. This cytokine is the primary determinant of the TME. Also proposed is the gut-lung dysbiosis concept and consequent degradation of ACE2 (richest in lungs and gut). Leaky gut induced autoantibodies related to G-protein coupled receptors (GPCRs) in combination with increased Ang II further potentiate oxidative stress. Aldosterone and paroxysmal orthostatic tachycardia syndrome (POTS) paradoxes are highlighted in the context of GPCR and gut dysbiosis, and the role of Candida is explored. The triple play of a prebiotic (d-mannose), probiotic (bifidobacteria and lactobacilli), and postbiotic (butyrate) might improve intestinal barrier integrity, oppose entry of GPCR antigens, suppress the inflammatory cytokine triad, balance IFN-γ and TGF-β, suppress oxidative stress, depress KTR, elevate HRV, and extend lifespan and its quality.