Immune microniches shape intestinal Treg function.

The intestinal immune system is highly adapted to maintaining tolerance to the commensal microbiota and self-antigens while defending against invading pathogens1,2. Recognizing how the diverse network of local cells establish homeostasis and maintains it in the complex immune environment of the gut is critical to understanding how tolerance can be re-established following dysfunction, such as in inflammatory disorders. Although cell and molecular interactions that control T regulatory (Treg) cell development and function have been identified3,4, less is known about the cellular neighbourhoods and spatial compartmentalization that shapes microorganism-reactive Treg cell function. Here we used in vivo live imaging, photo-activation-guided single-cell RNA sequencing5-7 and spatial transcriptomics to follow the natural history of T cells that are reactive towards Helicobacter hepaticus through space and time in the settings of tolerance and inflammation. Although antigen stimulation can occur anywhere in the tissue, the lamina propria-but not embedded lymphoid aggregates-is the key microniche that supports effector Treg (eTreg) cell function. eTreg cells are stable once their niche is established; however, unleashing inflammation breaks down compartmentalization, leading to dominance of CD103+SIRPα+ dendritic cells in the lamina propria. We identify and validate the putative tolerogenic interaction between CD206+ macrophages and eTreg cells in the lamina propria and identify receptor-ligand pairs that are likely to govern the interaction. Our results reveal a spatial mechanism of tolerance in the lamina propria and demonstrate how knowledge of local interactions may contribute to the next generation of tolerance-inducing therapies.

The lung is a site of platelet biogenesis and a reservoir for haematopoietic progenitors.

Platelets are critical for haemostasis, thrombosis, and inflammatory responses, but the events that lead to mature platelet production remain incompletely understood. The bone marrow has been proposed to be a major site of platelet production, although there is indirect evidence that the lungs might also contribute to platelet biogenesis. Here, by directly imaging the lung microcirculation in mice, we show that a large number of megakaryocytes circulate through the lungs, where they dynamically release platelets. Megakaryocytes that release platelets in the lungs originate from extrapulmonary sites such as the bone marrow; we observed large megakaryocytes migrating out of the bone marrow space. The contribution of the lungs to platelet biogenesis is substantial, accounting for approximately 50% of total platelet production or 10 million platelets per hour. Furthermore, we identified populations of mature and immature megakaryocytes along with haematopoietic progenitors in the extravascular spaces of the lungs. Under conditions of thrombocytopenia and relative stem cell deficiency in the bone marrow, these progenitors can migrate out of the lungs, repopulate the bone marrow, completely reconstitute blood platelet counts, and contribute to multiple haematopoietic lineages. These results identify the lungs as a primary site of terminal platelet production and an organ with considerable haematopoietic potential.

ILC3 GM-CSF production and mobilisation orchestrate acute intestinal inflammation.

Innate lymphoid cells (ILCs) contribute to host defence and tissue repair but can induce immunopathology. Recent work has revealed tissue-specific roles for ILCs; however, the question of how a small population has large effects on immune homeostasis remains unclear. We identify two mechanisms that ILC3s utilise to exert their effects within intestinal tissue. ILC-driven colitis depends on production of granulocyte macrophage-colony stimulating factor (GM-CSF), which recruits and maintains intestinal inflammatory monocytes. ILCs present in the intestine also enter and exit cryptopatches in a highly dynamic process. During colitis, ILC3s mobilize from cryptopatches, a process that can be inhibited by blocking GM-CSF, and mobilization precedes inflammatory foci elsewhere in the tissue. Together these data identify the IL-23R/GM-CSF axis within ILC3 as a key control point in the accumulation of innate effector cells in the intestine and in the spatio-temporal dynamics of ILCs in the intestinal inflammatory response.

Polycystic Ovarian Syndrome: A Primer.

Polycystic ovary syndrome (PCOS) affects 8-10 percent of reproductive-aged females, making it the most common state of endocrine dysfunction in women. Patients with PCOS are often treated for the signs and symptoms of the condition without consideration for the underlying syndrome, causing frustration for many affected patients. Abnormal uterine bleeding, endometrial hyperplasia and cancer, hirsutism and other skin changes, obesity, glucose intolerance, hypertension, and hyperlipidemia often accompany the syndrome, making it imperative to address these issues. The keys to diagnosis and treatment are understanding the diagnostic criteria of hyperandrogenism, ovulatory dysfunction, polycystic ovaries and the metabolic syndrome, while aiming treatment at controlling the symptoms and causes of the syndrome. In 2013, the Endocrine Society released its clinical guidelines, Diagnosis and Treatment of Polycystic Ovary Syndrome: An Endocrine Society Clinical Practice Guideline. This gives clear diagnostic criteria, and treatment goals aimed at the etiology of the syndrome: to decrease hyperandrogenic symptoms, management of underlying metabolic abnormalities, prevention of endometrial hyperplasia and carcinoma, and improvement of ovulation.

Symptoms During or Shortly After Isolated Carpal Tunnel Release and Problems Within 24 hours After Surgery.

This study used the National Survey of Ambulatory Surgery (NSAS) database to measure the incidence of and risk factors for symptoms in the ambulatory surgery center and problems within 24 h after isolated carpal tunnel release (CTR). The NSAS contained records on 400,000 adult patients with carpal tunnel syndrome who were treated with CTR in 2006, based on ICD-9 codes. The type of anesthesia used and factors associated with symptoms and problems were sought in bivariate and multivariable statistical analyses. The mean duration of the procedure was 16 ± 8.8 min. Only 5 % were performed under local anesthesia without sedation, 45 % with IV sedation, 28 % regional anesthesia, and 19 % general anesthesia. Symptoms in the ambulatory surgery center or a problem within 24 h after discharge were recorded in 10 % of patients, all of them minor and transient, including difficulties with pain and its treatment. The strongest risk factors were male sex, age of 45 years and older, and participation of an anesthesiologist. Local anesthesia and regional anesthesia were associated with more perioperative symptoms and postoperative problems. Most CTR are performed with some sedation in the United States. CTR is a safe procedure: one in 10 patients will experience a minor issue in the perioperative or immediate postoperative period.

Catastrophic Thinking Is Associated With Finger Stiffness After Distal Radius Fracture Surgery.

OBJECTIVES: To identify demographic, injury-related, or psychologic factors associated with finger stiffness at suture removal and 6 weeks after distal radius fracture surgery. We hypothesize that there are no factors associated with distance to palmar crease at suture removal. DESIGN: Prospective cohort study. SETTING: Level I Academic Urban Trauma Center. PATIENTS: One hundred sixteen adult patients underwent open reduction and internal fixation of their distal radius fractures; 96 of whom were also available 6 weeks after surgery. INTERVENTION: None. MAIN OUTCOME MEASUREMENTS: At suture removal, we recorded patients' demographics, AO fracture type, carpal tunnel release at the time of surgery, pain catastrophizing scale, Whiteley Index, Patient Health Questionnaire-9, and disabilities of the arm, shoulder, and hand questionnaire, 11-point ordinal measure of pain intensity, distance to palmar crease, and active flexion of the thumb through the small finger. At 6 weeks after surgery, we measured motion, disabilities of the arm, shoulder, and hand, and pain intensity. Prereduction and postsurgery radiographic fracture characteristics were assessed. RESULTS: Female sex, being married, specific surgeons, carpal tunnel release, AO type C fractures, and greater catastrophic thinking were associated with increased distance to palmar crease at suture removal. At 6 weeks, greater catastrophic thinking was the only factor associated with increased distance to palmar crease. CONCLUSIONS: Catastrophic thinking was a consistent and major determinant of finger stiffness at suture removal and 6 weeks after injury. Future research should assess if treatments that ameliorate catastrophic thinking can facilitate recovery of finger motion after operative treatment of a distal radius fracture. LEVEL OF EVIDENCE: Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Time Seeing a Hand Surgeon Is Not Associated With Patient Satisfaction.

BACKGROUND: Previous studies, predominantly in the primary care setting, identified time spent with the physician as an important predictor of satisfaction. It is unknown if the same holds true in hand surgery. QUESTIONS/PURPOSES: Is patient satisfaction measured immediately after an office visit associated with the duration of time spent with the hand surgeon? What other factors are associated with satisfaction directly after the visits and 2 weeks after the appointment? METHODS: We prospectively enrolled 81 patients visiting our hand and upper extremity surgery outpatient clinic. We recorded their demographics and measured physical function, pain behavior, symptoms of depression, time spent in the waiting room, time spent with the physician, and patient satisfaction. Office times were measured using our patient ambulatory tracking system and by a research assistant outside the clinic room. To assess satisfaction we used items from the Consumer Assessment of Healthcare Providers and Systems survey (a federally developed standardized survey instrument) relevant to our study. Two weeks later, 51 (64%) patients were available for telephone followup and the same measures were completed. Mean time spent with the hand surgeon was 8 ± 5 minutes and mean in-office wait time to see the hand surgeon was 32 ± 18 minutes. A priori power analyses indicated that 77 patients would provide 80% power to detect an effect size f(2) = 0.18 for a regression with five predictors. This means that we would detect time spent with the physician as a significant factor if it accounted for 7% or more of the variability in satisfaction. RESULTS: Time spent with the hand surgeon was not associated with patient satisfaction measured directly after the visit (r = -0.023; p = 0.84). Longer time waiting to see the physician correlated with decreased patient satisfaction (r = -0.30; p = 0.0057). The final multivariable model for increased satisfaction directly after the office visit included shorter waiting time (regression coefficient [ß] -0.0014; partial R(2) 0.094; 95% confidence interval [CI], -0.0024 to -0.00042; p = 0.006) and being married/living with a partner (ß 0.057; partial R(2) 0.11; 95% CI, 0.021-0.093; p = 0.002 [adjusted R(2) 0.18; p < 0.001]). Similarly, multivariable analysis found higher patient satisfaction 2 weeks after the visit to be independently associated with shorter waiting time (ß -0.0037; partial R(2) 0.10; 95% CI, -0.0070 to -0.00054; p = 0.023) and being married/living with a partner (ß 0.15; partial R(2) 0.12; 95% CI, 0.033-0.26; p = 0.012 [adjusted R(2) 0.16; p = 0.0052]). CONCLUSIONS: Patient satisfaction among patients undergoing hand surgery may relate more to shorter time in the waiting room and to the quality more than the quantity of time spent with the patient. LEVEL OF EVIDENCE: Level II, prognostic study.

The spatiotemporal cellular dynamics of lung immunity.

The lung is a complex structure that is interdigitated with immune cells. Understanding the 4D process of normal and defective lung function and immunity has been a centuries-old problem. Challenges intrinsic to the lung have limited adequate microscopic evaluation of its cellular dynamics in real time, until recently. Because of emerging technologies, we now recognize alveolar-to-airway transport of inhaled antigen. We understand the nature of neutrophil entry during lung injury and are learning more about cellular interactions during inflammatory states. Insights are also accumulating in lung development and the metastatic niche of the lung. Here we assess the developing technology of lung imaging, its merits for studies of pathophysiology and areas where further advances are needed.

Chitin activates parallel immune modules that direct distinct inflammatory responses via innate lymphoid type 2 and γδ T cells.

Chitin, a polysaccharide constituent of many allergens and parasites, initiates innate type 2 lung inflammation through incompletely defined pathways. We show that inhaled chitin induced expression of three epithelial cytokines, interleukin-25 (IL-25), IL-33, and thymic stromal lymphopoietin (TSLP), which nonredundantly activated resident innate lymphoid type 2 cells (ILC2s) to express IL-5 and IL-13 necessary for accumulation of eosinophils and alternatively activated macrophages (AAMs). In the absence of all three epithelial cytokines, ILC2s normally populated the lung but failed to increase IL-5 and IL-13. Although eosinophils and AAMs were attenuated, neutrophil influx remained normal without these epithelial cytokines. Genetic ablation of ILC2s, however, enhanced IL-1ß, TNFα, and IL-23 expression, increased activation of IL-17A-producing γδ T cells, and prolonged neutrophil influx. Thus, chitin elicited patterns of innate cytokines that targeted distinct populations of resident lymphoid cells, revealing divergent but interacting pathways underlying the tissue accumulation of specific types of inflammatory myeloid cells.

Innate lymphoid cells sustain colon cancer through production of interleukin-22 in a mouse model.

Patients with inflammatory bowel disease (IBD) have an increased risk of colon cancer. However, the immune cells and cytokines that mediate the transition from intestinal inflammation to cancer are poorly understood. We show that bacteria-induced colon cancer is accompanied by differential accumulation of IL-17(+)IL-22(+) colonic innate lymphoid cells (cILCs), which are phenotypically distinct from LTi and NK-22 cells, and that their depletion in mice with dysplastic inflammation blocks the development of invasive colon cancer. Analysis of the functional role of distinct Type 17 cytokines shows that although blockade of IL-17 inhibits some parameters of intestinal inflammation, reduction in dysplasia and colorectal cancer (CRC) requires neutralization of IL-22 indicating a unique role for IL-22 in the maintenance of cancer in this model. Mechanistic analyses showed that IL-22 selectively acts on epithelial cells to induce Stat3 phosphorylation and proliferation. Importantly, we could detect IL-22(+)CD3(+) and IL-22(+)CD3(−) cells in human CRC. Our results describe a new activity of IL-22 in the colon as a nonredundant mediator of the inflammatory cascade required for perpetuation of CRC, highlighting the IL-22 axis as a novel therapeutic target in colon cancer.