ZnT2-Mediated Zinc Import Into Paneth Cell Granules Is Necessary for Coordinated Secretion and Paneth Cell Function in Mice

BACKGROUND & AIMS

Defects in Paneth cell (PC) function are associated with microbial dysbiosis and intestinal inflammation. PC granules contain antimicrobial peptides, cytokines, and substantial stores of zinc (Zn). We hypothesized that Zn, transported into the granule through the Zn transporter (ZnT)2, is critical for signature PC functions.

METHODS

ZnT2 was localized to PC granules using immunofluorescence and sucrose gradient fractionation in wild-type (wt) mice, and consequences of ZnT2 loss were characterized in ZnT2 knockout (ZnT2ko) mice. Terminal ilea were harvested for immunofluorescence, electron microscopy, and fluorescent imaging with the Zn reporter Zinpyr-1. Alterations in fecal microbiota were characterized using 16s ribosomal RNA sequencing. PC degranulation, bacterial translocation, cytokine response to Escherichia coli endotoxin lipopolysaccharide, crypt viability after exposure to the oxidant monochloramine (NH₂Cl), and bactericidal activity of luminal contents of terminal ilea against enteropathogenic E coli were assessed.

RESULTS

ZnT2 was localized to the membrane of PC granules. In ZnT2ko mice, spontaneous degranulation was observed more frequently than among wt mice. Secretory granules were hypodense with less active lysozyme, and there was evidence of autophagosome accumulation and granule degradation in PCs from ZnT2ko mice. Gut microbiota of ZnT2ko mice were enriched in Bacteroidales S24-7 and relatively depleted of species commonly found in wt mice. Evidence of PC dysfunction in ZnT2ko mice included impaired granule secretion and increased inflammatory response to lipopolysaccharide, less bactericidal activity, and greater susceptibility to cell death from NH₂Cl.

CONCLUSIONS

ZnT2 is critical for Zn import into PC granules, and the inability to import Zn leads to profound defects in PC function and uncoordinated granule secretion.

Injuries and outcomes associated with traumatic falls in the elderly population on oral anticoagulant therapy

INTRODUCTION

Fall risk for older adults is a multi-factorial public health problem as 90% of geriatric injuries are caused by traumatic falls. The CDC estimated 33% of adults >65 years incurred a fall in 2011, with 30% resulting in moderate injury. While much has been written about overall risk to trauma patients on oral anticoagulant (OAC) therapy, less has been reported on outcomes in the elderly trauma population. We used data from the National Trauma Data Bank (NTDB) to identify the types of injury and complications incurred, length of stay, and mortality associated with OACs in elderly patients sustaining a fall.

METHODS

Using standard NTDB practices, data were collected on elderly patients (≥65 years) on OACs with diagnosis of fall as the primary mechanism of injury from 2007 to 2010. Univariate analysis was used to determine patient variables influencing risk of fall on OACs. Odds ratios were calculated for types of injury sustained and post-trauma complications. Logistic regression was used to determine mortality associated with type of injury incurred.

RESULTS

Of 118,467 elderly patients sampled, OAC use was observed in 444. Predisposing risk factors for fall on OACs were >1 comorbidity (p<0.0001). Patients on OACs were 188% and 370% more likely to develop 2 and >3 complications (p<0.0001); the most significant being ARDS and ARF (p<0.0001). The mortality rate on OACs was 16%. Injuries to the GI tract, liver, spleen, and kidney (p<0.0002) were more likely to occur. However, if patients suffered a mortality, the most significant injuries were skull fractures and intracranial haemorrhage (p<0.0001).

CONCLUSIONS

Risks of anticoagulation in elderly trauma patients are complex. While OAC use is a predictor of 30-day mortality after fall, the injuries sustained are markedly different between the elderly who die and those who do not. As a result there is a greater need for healthcare providers to identify preventable and non-preventable risks factors indicative of falls in the anti-coagulated elderly patient.

Endobronchial occlusion with one-way endobronchial valves: a novel technique for persistent air leaks in children

PURPOSE

In children, persistent air leaks can result from pulmonary infection or barotrauma. Management strategies include surgery, prolonged pleural drainage, ventilator manipulation, and extracorporeal membrane oxygenation (ECMO). We report the use of endobronchial valve placement as an effective minimally invasive intervention for persistent air leaks in children.

METHODS

Children with refractory prolonged air leaks were evaluated by a multidisciplinary team (pediatric surgery, interventional pulmonology, pediatric intensive care, and thoracic surgery) for endobronchial valve placement. Flexible bronchoscopy was performed, and air leak location was isolated with balloon occlusion. Retrievable one-way endobronchial valves were placed.

RESULTS

Four children (16 months to 16 years) had prolonged air leaks following necrotizing pneumonia (2), lobectomy (1), and pneumatocele (1). Patients had 1-4 valves placed. Average time to air leak resolution was 12 days (range 0-39). Average duration to chest tube removal was 25 days (range 7-39). All four children had complete resolution of air leaks. All were discharged from the hospital. None required additional surgical interventions.

CONCLUSION

Endobronchial valve placement for prolonged air leaks owing to a variety of etiologies was effective in these children for treating air leaks, and their use may result in resolution of fistulae and avoidance of the morbidity of pulmonary surgery.

Transumbilical laparoscopic-assisted appendectomy is associated with lower costs compared to multiport laparoscopic appendectomy

BACKGROUND/PURPOSE

Single-incision laparoscopic appendectomy has been associated with improved cosmetic benefits, and decreased postoperative pain. Less is known about costs and other outcomes. Our aim was to evaluate the costs and outcomes between transumbilical laparoscopic-assisted appendectomy (TULAA) and multiport laparoscopic appendectomy (MLA).

METHODS

IRB-approved retrospective review (September 2010-July 2013) of institutional medical records identified 372 pediatric patients undergoing laparoscopic appendectomy. Outcomes included costs, LOS and readmission. Costs were fully loaded operating costs from the hospital's cost accounting database. Generalized linear regression was used to assess costs of MLA and TULAA. A subgroup analysis was performed using only patients with non-perforated appendicitis.

RESULTS

There were 132 patients (35.5%) that underwent TULAA while 240 patients (65.5%) underwent MLA. Compared to MLA, TULAA was associated with decreased operative time (0.6 vs. 1.0h, p<0.0001), used in comparable proportions of interval appendectomies, but was performed less often for perforated appendicitis (9.8% vs. 22.9%, p=0.002). Readmission and postoperative complications were similar between both groups. In the setting of non-perforated appendicitis, TULAA was associated with lower costs of $1378 relative to MLA (p=0.009).

CONCLUSIONS

In non-perforated appendicitis, TULAA is associated with lower costs and comparable rates of readmission and postoperative complications.

Mannose-binding lectin serum levels are low in persons with clinically active coccidioidomycosis

BACKGROUND

Mannose-binding lectin (MBL) is a circulating collectin that is part of the innate immune response. We explored the serum levels of MBL in persons with different forms of coccidioidomycosis.

METHODS

Serum MBL was measured by ELISA from samples obtained from healthy donors with immunity to Coccidioides, and those with various forms of active coccidioidomycosis. Blood cell specimens from a subgroup of subjects with active coccidioidomycosis were examined for single nucleotide polymorphisms of the MBL gene and promoter regions.

RESULTS

The control group comprised 29 healthy immune subjects. Patient groups with active coccidioidomycosis consisted of 20 patients with symptomatic primary pulmonary coccidioidomycosis, 26 with non-meningeal disseminated coccidioidomycosis, and nine with coccidioidal meningitis. The group with active coccidioidomycosis was significantly older and more likely to be male than the control group (for both, P < 0.001). The mean +/- SEM level of serum MBL in the healthy controls was 169.4 +/- 28.6 ng/ml, significantly higher than the 79.2 +/- 10.9 ng/ml for all active groups (P < 0.001). Moreover, the active coccidioidomycosis group was significantly more likely to have serum MBL level <or=70 ng/ml compared to the control group (P = 0.001). Genetic analysis in 27 subjects with active coccidioidomycosis revealed marked variation based on race and ethnicity. Among a subgroup of 10 white, non-hispanic men with active coccidioidomycosis, there was a significant association between the H and P haplotypes and MBL levels <or=70 ng/ml (P < 0.036 and P < 0.035, respectively).

CONCLUSIONS

These data suggest that there is an association between low serum MBL levels and symptomatic coccidioidomycosis.

Spherules derived from Coccidioides posadasii promote human dendritic cell maturation and activation

Previous studies have shown that dendritic cells (DC) pulsed with T27K, an antigenic preparation derived from spherules (of Coccidioides posadasii), activate peripheral blood mononuclear cells (PBMC) from nonimmune subjects as well as from patients with disseminated coccidioidomycosis. In this study, we have assessed the interaction between human DC and C. posadasii spherules in order to better understand the initial response between Coccidioides and the human host. Whole autoclaved spherules induced lymphocyte transformation in PBMC obtained from immune but not from nonimmune donors. Immature DC (iDC) bound fluorescein isothiocyanate-labeled spherules in a time- and temperature-dependent manner. This binding was blocked by the addition of mannan, suggesting mannose receptor involvement in the DC-Coccidioides interaction. Binding was subsequently associated with ingestion and intracellular processing of spherules. Coculturing of spherules with iDC was associated with the development of mature DC that were morphologically, phenotypically, and functionally similar to those induced by tumor necrosis factor alpha and prostaglandin E2. Finally, spherules incubated with iDC induced activation of PBMC from nonimmune donors. These data indicate that human DC are capable of binding, internalizing, and presenting antigens from Coccidioides spherules and suggest that DC may play a critical early role in the formation of a cellular immune response in human coccidioidomycosis.