Sunali Goyal

Autoimmunity in Dry Eye Is Due to Resistance of Th17 to Treg Suppression

Dry eye disease (DED), an inflammatory autoimmune disorder affecting the ocular surface, degrades visual performance and the quality of life of >10 million people in the United States alone. The primary limitation in the effective treatment of DED is an incomplete understanding of its specific cellular and molecular pathogenic elements. Using a validated mouse model of DED, herein we functionally characterize the different T cell subsets, including regulatory T cells (Tregs) and pathogenic effector T cells, and determine their contribution to the pathogenesis of DED. Our data demonstrate the presence of dysfunctional Tregs and the resistance of pathogenic T cells, particularly Th17 cells, to Treg suppression in DED. In addition, we clearly show that in vivo blockade of IL-17 significantly reduces the severity and progression of disease, which is paralleled by a reduction in the expansion of Th17 cells and restoration of Treg function. Our findings elucidate involvement of a previously unknown pathogenic T cell subset (Th17) in DED that is associated specifically with Treg dysfunction and disease pathogenesis and suggest a new target for dry eye therapy.

A novel pro-lymphangiogenic function for Th17/IL-17

Th17 cells, in addition to their proinflammatory functions, have been recognized as potent inducers of angiogenesis in autoimmune diseases and malignancies. In the present study, we demonstrate distinct mechanisms by which IL-17 induces lymphangiogenesis. Using the mouse cornea micropocket and cell culture assays, our data demonstrate that IL-17 directly promotes growth of lymphatic vessels by inducing increased expression of prolymphangiogenic VEGF-D and proliferation of lymphatic endothelial cells. However, IL-17-induced growth of blood vessels is primarily mediated through IL-1β secretion by IL-17-responsive cells. Furthermore, in vivo blockade of IL-17 in a preclinical model of Th17-dominant autoimmune ocular disease demonstrates a significant reduction in the corneal lymphangiogenesis and in the progression of clinical disease. Taken together, our findings demonstrate a novel prolymphangiogenic function for Th17/IL-17, indicating that IL-17 can promote the progression and amplification of immunity in part through its induction of lymphangiogenesis.

Evidence of Corneal Lymphangiogenesis in Dry Eye Disease A Potential Link to Adaptive Immunity

OBJECTIVE To determine the effect of desiccating stress on corneal angiogenic responses in dry eye disease (DED) using a murine model. METHODS Dry eye was induced in murine eyes using high-flow desiccated air. Corneas were double stained with CD31 (panendothelial marker) and LYVE-1 (lymphatic endothelial marker). Real-time polymerase chain reaction was performed to quantify expression of vascular endothelial growth factors (VEGF-A, VEGF-C, and VEGF-D) and their receptors (VEGFR-2 and VEGFR-3) in the cornea on days 6, 10, and 14. Enumeration of CD11b(+)/LYVE-1(+) monocytic cells was performed in corneas with DED on day 14. Flow cytometric evaluation of the draining lymph nodes in normal mice and mice with DED was performed to determine whether DED is associated with homing of mature (major histocompatibility complex class II(hi)) antigen-presenting cells to the lymphoid compartment. RESULTS Lymphatic vessels unaccompanied by blood vessels were seen growing toward the center of corneas with DED. Significant increases in lymphatic area (P < .001) and lymphatic caliber (P < .02) were seen on day 14 of disease. Lymphangiogenic-specific VEGF-D and VEGFR-3 levels increased earliest on day 6 followed by increased VEGF-C, VEGF-A, and VEGFR-2 levels. Increased recruitment of CD11b(+)/LYVE-1(+) monocytic cells to the cornea and homing of mature CD11b(+) antigen-presenting cells to the draining lymph nodes were also associated with DED. CONCLUSION Low-grade inflammation associated with DED is an inducer of lymphangiogenesis without accompanying hemangiogenesis.

Amelioration of Murine Dry Eye Disease by Topical Antagonist to Chemokine Receptor 2

OBJECTIVE To determine the effect of a topical antagonist to the chemokine receptor 2 (CCR2) in a murine model of dry eye disease. METHODS The effects of a topical CCR2 antagonist and a vehicle control treatment were studied in murine dry eyes. A controlled environment chamber induced dry eye by exposing mice to high-flow desiccated air. Corneal fluorescein staining and enumeration of corneal CD11b(+) and conjunctival CD3(+) T cells were performed in the different groups. Real-time polymerase chain reaction was performed to quantify expression of different inflammatory cytokine transcripts in the cornea and conjunctiva. RESULTS Eyes receiving the formulation containing CCR2 antagonist showed a significant decrease in corneal fluorescein staining and decreased infiltration of corneal CD11b(+) cells and conjunctival T cells compared with the vehicle-treated and untreated dry eye groups. The CCR2 antagonist also significantly decreased messenger RNA expression levels of interleukins 1alpha and 1beta in the cornea, and tumor necrosis factor alpha and interleukin 1beta in the conjunctiva. CONCLUSION Topical application of CCR2 antagonist is associated with significant improvement in dry eye disease and is reflected by a decrease in inflammation at the clinical, molecular, and cellular levels. Clinical Relevance Topical application of CCR2 antagonist may hold promise as a therapeutic modality in dry eye disease.

Blockade of Prolymphangiogenic Vascular Endothelial Growth Factor C in Dry Eye Disease

OBJECTIVE To determine whether blocking prolymphangiogenic factors such as vascular endothelial growth factor C (VEGF-C) would suppress alloimmunity in dry eye disease using a murine model. METHODS The effects of intraperitoneal injections of 400 μg of anti-VEGF-C antibody (treated group) and intraperitoneal normal saline (untreated group) were studied in murine dry eyes induced by exposing mice to high-flow desiccated air in a controlled-environment chamber. Growth of lymphatic vessels and infiltration of macrophages were evaluated by immunohistochemistry using CD31 (panendothelial marker), lymphatic vessel endothelial receptor 1 (lymphatic endothelial marker), and CD11b (monocyte and macrophage marker). Real-time polymerase chain reaction was performed to quantify expression of different inflammatory cytokine transcripts in the conjunctiva and lymph nodes as well as vascular endothelial growth factors and their receptors (VEGF-A, VEGF-C, VEGF-D, VEGFR-2, and VEGFR-3) in the cornea. RESULTS Blocking VEGF-C led to significant reductions in lymphatic caliber (P = .02) and lymphatic area (P = .006) in the corneas of mice with dry eye disease. In addition to significantly decreasing CD11b(+) cells (P = .005), anti-VEGF-C treatment significantly decreased transcript levels of VEGF-C (P = .002), VEGF-D (P = .01), and VEGFR-3 (P = .02) in the corneas of the treated group. A significant decrease in expression of inflammatory cytokines in the conjunctiva (interleukin 1α, P = .003; interleukin 1β, P = .02; interleukin 6, P = .005) and lymph nodes (interferon γ, P = .008; interleukin 17, P = .003) was also seen with anti-VEGF-C treatment. CONCLUSION Treatment with anti-VEGF-C led to significant improvement in dry eye disease, reflected by a decrease in inflammation at the clinical, molecular, and cellular levels. CLINICAL RELEVANCE Targeting prolymphangiogenic growth factors or their receptors could inhibit the trafficking of antigen-presenting cells to the draining lymph nodes and hence prove to be a potential therapeutic target for dry eye disease.

Regulation of T-Cell Chemotaxis by Programmed Death-Ligand 1 (PD-L1) in Dry Eye–Associated Corneal Inflammation

PURPOSE. Given that dry eye disease (DED) is associated with T cell-mediated inflammation of the ocular surface and that PD-L1 is an important negative or inhibitory regulator of immune responses constitutively expressed at high levels by corneal epithelial cells, the authors studied the expression and function of PD-L1 in DED. METHODS. Dry eye was induced in untreated wild-type mice, PD-L1(-/-) mice, and wild-type mice treated with anti-PD-L1 antibody by exposing these mice to a desiccating environment in the controlled environment chamber modified with subcutaneous administration of scopolamine. Real-time PCR was used to quantify the expression of chemokine gene transcript levels of multiple CC and CXC chemokine ligands and receptors. Epifluorescence microscopy was used to evaluate corneal infiltration of CD3(+) T cells after immunohistochemical staining. RESULTS. The increased expression of specific chemokine ligands and receptors in PD-L1(-/-) corneas of normal mice is associated with significant increases in T-cell homing into these corneas. Similar, and more enhanced, increases in T-cell infiltration were observed in PD-L1(-/-) DED mice or DED mice treated with anti-PD-L1 antibody compared with controls. In addition, the authors found significantly decreased expression of PD-L1 by corneal epithelial cells in DED and significantly increased corneal fluorescein staining score with PD-L1 functional blockade using anti-PD-L1 antibody. CONCLUSIONS. Downregulation of corneal epithelial PD-L1 amplifies dry eye-associated corneal inflammation and epitheliopathy by increasing the expression of chemokine ligands and receptors that promote T-cell homing to the ocular surface.

Sudden cardiac death under anesthesia in pediatric patient with williams syndrome: A case report and review of literature

Williams syndrome is a complex syndrome characterized by developmental abnormalities, craniofacial dysmorphic features, and cardiac anomalies. Sudden death has been described as a very common complication associated with anesthesia, surgery, and procedures in this population. Anatomical abnormalities associated with the heart pre-dispose these individuals to sudden death. In addition to a sudden and rapid downhill course, lack of response to resuscitation is another significant feature seen in these patients. The authors report a five-year-old male with Williams syndrome, hypothyroidism, and attention deficit hyperactivity disorder. He suffered an anaphylactic reaction during CT imaging with contrast. Resuscitation was unsuccessful. Previous reports regarding the anesthetic management of patients with Williams are reviewed and the potential for sudden death or peri-procedure related cardiac arrest discussed in this report. The authors also review reasons for refractoriness to defined resuscitation guidelines in this patient population.

Toxic epidermal necrolysis in children: medical, surgical, and ophthalmologic considerations.

Toxic epidermal necrolysis is a rare acute inflammatory multisystem life-threatening condition characterized by widespread epidermal necrosis and profound toxic systemic reaction. Implicated etiologic agents in children include drugs, infections, and autoimmune diseases. The pathophysiology includes separation of the epidermis at the dermal–epidermal junction of both skin and extracutaneous epithelium and mucous membranes. The general consensus is that expeditious transfer to a burn center, maintenance of fluid and electrolyte balance, temperature maintenance, control of evaporative losses, avoidance of use of complicating drugs as corticosteroids and topical sulfa compounds, aggressive septic surveillance, vigorous nutritional support via nasoenteric tube, early ophthalmologic consultation, and appropriate wound care with a regimen of therapy relying on basic principles of treatment of partial-thickness epidermal wounds predict better outcome in the treatment of this disease process. The course of toxic epidermal necrolysis in children, even though dramatic at onset, leads to low mortality when managed appropriately. The current limited published evidence does not clearly delineate differences in epidemiology, pathogenesis, and prognosis of severe skin reactions in children as compared with adults. In this article, we review the available literature on the pathogenesis, clinical features, pathophysiology, treatment, and complications of this rare disease in children.

Understanding Neuropathic Corneal Pain—Gaps and Current Therapeutic Approaches

ABSTRACT The richly innervated corneal tissue is one of the most powerful pain generators in the body. Corneal neuropathic pain results from dysfunctional nerves causing perceptions such as burning, stinging, eye-ache, and pain. Various inflammatory diseases, neurological diseases, and surgical interventions can be the underlying cause of corneal neuropathic pain. Recent efforts have been made by the scientific community to elucidate the pathophysiology and neurobiology of pain resulting from initially protective physiological reflexes, to a more persistent chronic state. The goal of this clinical review is to briefly summarize the pathophysiology of neuropathic corneal pain, describe how to systematically approach the diagnosis of these patients, and finally summarizing our experience with current therapeutic approaches for the treatment of corneal neuropathic pain.

Extubation failure in infants with shunt-dependent pulmonary blood flow and univentricular physiology.

OBJECTIVE The objective of the study was to identify incidence, aetiology, and outcomes of extubation failure in infants with shunt-dependent pulmonary blood flow at a single tertiary care, academic childrens hospital. The second objective of this study was to determine the haemodynamic effects of transition of positive pressure ventilation to spontaneous breathing in infants with extubation failure. PATIENTS AND METHODS Extubation failure for our study was defined as the need for positive pressure ventilation within 96 hours after extubation. We collected demographics, pre-operative, intra-operative, post-operative, and peri-extubation data in a retrospective, observational format in patients who underwent a modified Blalock-Taussig shunt between January, 2005 and March, 2011. Infants undergoing Norwood operation or Damus-Kaye-Stansel with modified Blalock-Taussig shunt were excluded from the study. The cardiorespiratory variables collected before extubation and immediately after extubation included heart rate, respiratory rate, mean arterial blood pressure, central venous pressures, near infrared spectroscopy, oxygen saturations, and lactate levels. Clinical outcomes evaluated included the success or failure of extubation, cardiovascular intensive care unit length of stay, hospital length of stay, and mortality. Descriptive and univariate statistics were utilised to compare groups with extubation failure and extubation success. RESULTS Of the 55 eligible patients during the study period, extubation failure occurred in 27% (15/55) of the patients. Of the 15 patients with extubation failure, 10 patients needed reintubation and five patients received continuous positive pressure ventilation without getting reintubated. There were three patients who had extubation failure in the first 2 hours after extubation, nine patients in the 2-24-hour period, and three patients in the 24-96-hour period. In all, eight patients were extubated in the second attempt after the first extubation failure, with a median duration of mechanical ventilation of 2 days (1 day, 6 days). The median age of patients at extubation was 19 days (12 days, 22 days) and median weight of patients was 3.6 kg (3.02 kg, 4.26 kg). In all, 38% (21/55) of the patients were intubated before surgery. The most common risk factors for failed extubation were lung disease in 46% (7/15), cardiac dysfunction in 26% (4/15), diaphragmatic paralysis in 13% (2/15), airway oedema in 6% (1/15), and vocal cord paralysis in 6% (1/15). The median duration of mechanical ventilation was 4 days (1 day, 10.5 days), median cardiovascular intensive care unit length of stay was 11 days (6.5 days, 23.5 days), and the median hospital length of stay was 30 days (14 days, 48 days). The overall mortality at the time of hospital discharge was 7%. CONCLUSIONS Extubation failure in infants with shunt-dependent pulmonary blood flow and univentricular physiology is high and aetiology is diverse. Cardiopulmonary effects of removal of positive pressure ventilation are more pronounced in children with extubation failure and include escalation in the need for oxygen requirement and increase in mean arterial blood pressure. The majority of extubation failures in this select patient population occurs in the first 24 hours. Extubation failure in these patients is not associated with increased hospital length of stay or mortality.