Olfactory Results of Endoscopic Endonasal Surgery for Pituitary Adenoma: A Prospective Study of 143 Patients

BACKGROUND

Clinical examination, including pre- and postoperative assessment of olfaction function, should be included in evaluating surgical outcomes in patients with pituitary adenomas. Most of the studies are lacking assessment of olfactory function.

METHODS

A prospective study of 143 patients who underwent surgical resection of pituitary adenomas from January 2014 to December 2017 was performed. Data on clinical presentation, pre- and postoperative neurologic, endocrinologic, and ophthalmologic examinations, complications, and follow-up outpatient examinations were recorded. Olfactory function was assessed using the Sniffin' Sticks odor identification test preoperatively, postoperatively (3 months), and 1 year after surgery.

RESULTS

Normosmia was present preoperatively in 93.7% of patients, postoperatively in 95.8% of patients, and in 95.1% 1 year postsurgery. Hyposmia was present preoperatively in 4.2% of patients, postoperatively in 2.1% of patients, and in 1.4% 1 year after surgery. Anosmia was present preoperatively in 2.1% of patients, postoperatively in 2.1% of patients, and in 3.5% 1 year after surgery. In patients with preoperative normosmia, postoperative hyposmia and anosmia were present in 1.5% of patients. There were no differences according to age, sex, size, or type of pituitary adenoma.

CONCLUSIONS

Assessment of olfactory function should be included in the analysis of pituitary adenoma surgery results. This prospective study showed low risk of olfaction deterioration if an endoscopic endonasal approach is used without any mucosal flaps for skull base reconstruction. Further studies that include objective olfaction assessment are warranted.

Tolerogenic Dendritic Cells from Poorly Compensated Type 1 Diabetes Patients Have Decreased Ability To Induce Stable Antigen-Specific T Cell Hyporesponsiveness and Generation of Suppressive Regulatory T Cells

Tolerogenic dendritic cells (tolDCs) may offer an interesting intervention strategy to re-establish Ag-specific tolerance in autoimmune diseases, including type 1 diabetes (T1D). T1D results from selective destruction of insulin-producing β cells leading to hyperglycemia that, in turn, specifically affects a patient's immune system. In this study, we prepared monocyte-derived tolDCs modulated by dexamethasone and vitamin D₂ from 31 T1D patients with optimal glycemic control and 60 T1D patients with suboptimal glycemic control and assessed their tolerogenic properties in correlation with metabolic state of patients. tolDCs differentiated from both groups of patients acquired a regulatory phenotype and an anti-inflammatory profile. Interestingly, tolDCs from well-controlled patients expressed higher levels of inhibitory molecules IL-T3 and PD-L1. Additionally, glutamic acid decarboxylase (GAD)65-loaded tolDCs from well-controlled patients decreased significantly primary Th1/Th17 responses, induced stable GAD65-specific T cell hyporesponsiveness, and suppressed markedly control DC-induced GAD65-specific T cell activation compared with poorly controlled patients. The ability of tolDCs from poorly controlled patients to induce durable GAD65-specific T cell hyporesponsiveness was reversed once the control of glycemia improved. In both groups of patients, tolDCs were able to induce regulatory T cells from autologous naive CD4⁺ T cells. However, regulatory T cells from well-controlled patients had better suppressive abilities. The functionality of tolDCs was confirmed in the adoptive transfer model of NOD-SCID mice where tolDCs delayed diabetes onset. These results suggest that metabolic control of T1D affects the functional characteristics of tolDCs and subsequent effector T cell responses. Metabolic control may be relevant for refining inclusion criteria of clinical trials in the settings of T1D.

Pepsin digest of wheat gliadin fraction increases production of IL-1β via TLR4/MyD88/TRIF/MAPK/NF-κB signaling pathway and an NLRP3 inflammasome activation

Celiac disease (CD) is a gluten-responsive, chronic inflammatory enteropathy. IL-1 cytokine family members IL-1β and IL-18 have been associated with the inflammatory conditions in CD patients. However, the mechanisms of IL-1 molecule activation in CD have not yet been elucidated. We show in this study that peripheral blood mononuclear cells (PBMC) and monocytes from celiac patients responded to pepsin digest of wheat gliadin fraction (PDWGF) by a robust secretion of IL-1β and IL-1α and a slightly elevated production of IL-18. The analysis of the upstream mechanisms underlying PDWGF-induced IL-1β production in celiac PBMC show that PDWGF-induced de novo pro-IL-1β synthesis, followed by a caspase-1 dependent processing and the secretion of mature IL-1β. This was promoted by K+ efflux and oxidative stress, and was independent of P2X7 receptor signaling. The PDWGF-induced IL-1β release was dependent on Nod-like receptor family containing pyrin domain 3 (NLRP3) and apoptosis-associated speck like protein (ASC) as shown by stimulation of bone marrow derived dendritic cells (BMDC) from NLRP3(-/-) and ASC(-/-) knockout mice. Moreover, treatment of human PBMC as well as MyD88(-/-) and Toll-interleukin-1 receptor domain-containing adaptor-inducing interferon-β (TRIF)(-/-) BMDC illustrated that prior to the activation of caspase-1, the PDWGF-triggered signal constitutes the activation of the MyD88/TRIF/MAPK/NF-κB pathway. Moreover, our results indicate that the combined action of TLR2 and TLR4 may be required for optimal induction of IL-1β in response to PDWGF. Thus, innate immune pathways, such as TLR2/4/MyD88/TRIF/MAPK/NF-κB and an NLRP3 inflammasome activation are involved in wheat proteins signaling and may play an important role in the pathogenesis of CD.

The role of gut microbiota (commensal bacteria) and the mucosal barrier in the pathogenesis of inflammatory and autoimmune diseases and cancer: contribution of germ-free and gnotobiotic animal models of human diseases

Metagenomic approaches are currently being used to decipher the genome of the microbiota (microbiome), and, in parallel, functional studies are being performed to analyze the effects of the microbiota on the host. Gnotobiological methods are an indispensable tool for studying the consequences of bacterial colonization. Animals used as models of human diseases can be maintained in sterile conditions (isolators used for germ-free rearing) and specifically colonized with defined microbes (including non-cultivable commensal bacteria). The effects of the germ-free state or the effects of colonization on disease initiation and maintenance can be observed in these models. Using this approach we demonstrated direct involvement of components of the microbiota in chronic intestinal inflammation and development of colonic neoplasia (i.e., using models of human inflammatory bowel disease and colorectal carcinoma). In contrast, a protective effect of microbiota colonization was demonstrated for the development of autoimmune diabetes in non-obese diabetic (NOD) mice. Interestingly, the development of atherosclerosis in germ-free apolipoprotein E (ApoE)-deficient mice fed by a standard low-cholesterol diet is accelerated compared with conventionally reared animals. Mucosal induction of tolerance to allergen Bet v1 was not influenced by the presence or absence of microbiota. Identification of components of the microbiota and elucidation of the molecular mechanisms of their action in inducing pathological changes or exerting beneficial, disease-protective activities could aid in our ability to influence the composition of the microbiota and to find bacterial strains and components (e.g., probiotics and prebiotics) whose administration may aid in disease prevention and treatment.

A subset of human pancreatic beta cells express functional CD14 receptors: a signaling pathway for beta cell-related glycolipids, sulfatide and β-galactosylceramide

BACKGROUND

T1DM is a T-cell-mediated autoimmune disease targeting insulin-producing beta-cells. Multiple factors may contribute to the development of T1DM. Among these, the metabolic state of beta-cells and pro-inflammatory cytokines, produced by infiltrating immune cells, have been implicated in the precipitation of T1DM.

METHODS AND RESULTS

In this study, confocal immunofluorescence microscopy of human pancreata revealed a distinct subset of beta-cells expressing the innate LPS co-receptor CD14. Human islets expressed fully functional CD14 as LPS stimulation led to a dose-dependent secretion of tumour necrosis factor (TNFα), interleukin (IL)-1β and IL-8, which were substantially inhibited by a blocking anti-CD14 mAb. In addition, LPS stimulation impaired the glucose-mediated insulin secretion in rat islets. β-GalCer and sulfatide, glycolipids that are related to insulin processing and secretion, are possibly interacting with the CD14 receptor complex. β-GalCer had an LPS-like, serum- and CD14-dependent effect on the induction of pro-inflammatory cytokines in a human monocyte cell line. In contrast, the LPS-mediated cytokine production was inhibited by sulfatide. Human islets also responded to β-GalCer (10 µg/mL) by secreting TNFα, IL-1β and IL-8, whereas sulfatide partly inhibited the effect of LPS.

CONCLUSIONS

A subset of human beta-cells expresses functional CD14 receptor and thus is able to recognize both exogenous bacterial (LPS) as well as endogenous ligands (e.g. glycolipids of beta-cell origin). The CD14 expression on a subset of human beta-cells may play a role in the innate surveillance of the endocrine environment but may also contribute to innate immune mechanisms in the early stages of beta-cell aggression.

Expression of IGF-1R and iNOS in nasal polyps; epithelial cell homeostasis and innate immune mechanisms in pathogenesis of nasal polyposis

Nasal polyps (NP), edematous projections of nasal mucosa (NM), are characterized by an inflammatory cellular infiltrate, however, little is known about etiopathogenesis of NP. Both innate immune mechanisms leading to activation of NF-kappaB and homeostasis of epithelial cells were implicated in the pathogenesis of NP. In this study we investigated the expression of insulin-like growth factor-1 receptor (IGF-1R) and inducible nitric-oxide synthase (iNOS) in NP compared to healthy NM in both the epithelial and stromal compartments. Using immunohistochemistry, frozen tissue sections of NP from 18 patients, and mucosal biopsy specimens of the inferior turbinate from 17 subjects were stained for IGF-1R and iNOS markers. Fluorescence microscopy and computerized image analysis revealed low numbers of IGF-1R-positive cells in all specimens. However, substantially increased numbers of IGF-1R-positive cells were found in NP compared to NM both within the epithelium (1.63 vs. 0.43) and stroma (3.27 vs. 1.03). Positivity for iNOS was detected within the epithelium of NP compared with NM. Numbers of iNOS-positive single cells were highly increased in NP vs. NM in both epithelial (3.83 vs. 1.08) and stromal (4.96 vs. 2.67) compartments. An increased iNOS expression within the epithelial layer as well as increased number of iNOS- and IGF-1R-positive cells in NP was observed. This suggests that innate immune mechanism, and to a lesser extent also growth and homeostasis of epithelial cells, may play a role in formation of NP.

Mucosal immunity: its role in defense and allergy

The interface between the organism and the outside world, which is the site of exchange of nutrients, export of products and waste components, must be selectively permeable and at the same time, it must constitute a barrier equipped with local defense mechanisms against environmental threats (e.g. invading pathogens). The boundaries with the environment (mucosal and skin surfaces) are therefore covered with special epithelial layers which support this barrier function. The immune system, associated with mucosal surfaces covering the largest area of the body (200-300 m(2)), evolved mechanisms discriminating between harmless antigens and commensal microorganisms and dangerous pathogens. The innate mucosal immune system, represented by epithelial and other mucosal cells and their products, is able to recognize the conserved pathogenic patterns on microbes by pattern recognition receptors such as Toll-like receptors, CD14 and others. As documented in experimental gnotobiotic models, highly protective colonization of mucosal surfaces by commensals has an important stimulatory effect on postnatal development of immune responses, metabolic processes (e.g. nutrition) and other host activities; these local and systemic immune responses are later replaced by inhibition, i.e. by induction of mucosal (oral) tolerance. Characteristic features of mucosal immunity distinguishing it from systemic immunity are: strongly developed mechanisms of innate defense, the existence of characteristic populations of unique types of lymphocytes, colonization of the mucosal and exocrine glands by cells originating from the mucosal organized tissues ('common mucosal system') and preferential induction of inhibition of the responses to nondangerous antigens (mucosal tolerance). Many chronic diseases, including allergy, may occur as a result of genetically based or environmentally induced changes in mechanisms regulating mucosal immunity and tolerance; this leads to impaired mucosal barrier function, disturbed exclusion and increased penetration of microbial, food or airborne antigens into the circulation and consequently to exaggerated and generalized immune responses to mucosally occurring antigens, allergens, superantigens and mitogens.

Cystic vestibular schwannoma: surgical outcome

We investigated the proportion of the cystic form of vestibular schwannoma and assessed the results of surgery in this subtype of the condition. The definition of cystic vestibular schwannomas was based on the following criteria: per-operative identification of cystic components; occurrence of the hypodense/hypointense areas on computed tomography (CT) and/or magnetic resonance (MR); and histological verification of S-100 protein membrane-like structures. In a study of 773 Danish patients with vestibular schwannomas, 44 (5.7 per cent) displayed cystic components. The outcome of surgery on 44 cystic vestibular schwannoma (mean tumour size 39 mm) was evaluated and compared with that for 151 solid grant vestibular schwannoma (mean tumour size 49.8 mm). Per-operatively, we found a substantially higher adherence to different intracranial structures in the solid giant vestibular schwannoma compared with the cystic vestibular (95 per cent vs 70 per cent for brainstem, 91 per cent vs 59 per cent for trigeminal nerve, 85 per cent vs 45 per cent for cranial nerves X and XI, 67 per cent vs 32 per cent for dura). Nevertheless, the preservation of the facial nerve function was much better in patients with solid giant vestibular schwannoma compared with those with cystic vestibular schwannoma (House-Brackmann facial nerve dysfunction grade 6 (one year post-operative): 27 per cent vs 41 per cent, respectively p < 0.04). We conclude that the cystic components in vestibular schwannoma are associated with a less favourable surgical outcome, probably due to the rapid tumour growth and symptoms caused by compression of the posterior fossa structures.