Healthy Human Laryngopharyngeal Sensory Innervation Density Correlates with Age.

OBJECTIVE: Somatosensory feedback from upper airway structures is essential for swallowing and airway defense but little is known about the identities and distributions of human upper airway neurons. Furthermore, whether sensory innervation modifies with aging is unknown. In this study, we quantify neuronal and chemosensory cell density in upper airway structures and correlate with age. METHODS: Participants underwent biopsies from base of tongue, lateral and midline pharyngeal wall, epiglottis, and arytenoids (N = 25 13 female/12 male; 20-80 years, mean 51.4 years without clinical diagnosis of dysphagia or clinical indication for biopsy). Tissue sections were labeled with antibodies for all neurons, myelinated neurons, and chemosensory cells. Densities of lamina propria innervation, epithelial innervation, solitary chemosensory cells, and taste buds were calculated and correlated with age. RESULTS: Arytenoid had the highest density of innervation and chemosensory cells across all measures compared to other sites. Taste buds were frequently observed in arytenoid and epiglottis. Base of tongue, lateral pharynx, and midline posterior pharynx had minimal innervation and few chemosensory cells. Epithelial innervation was present primarily in close proximity to chemosensory cells and taste buds. Overall innervation and myelinated fibers in the arytenoid lamina propria decline with aging. CONCLUSION: Findings establish the architecture of healthy adult sensory innervation and demonstrate the varied distribution of laryngopharyngeal innervation, necessary steps toward understanding the sensory basis for swallowing and airway defense. We also document age-related decline in arytenoid innervation density. These findings suggest that sensory afferent denervation of the upper airway may be a contributing factor to presbyphagia. LEVEL OF EVIDENCE: NA Laryngoscope, 133:773-784, 2023.

The humanistic burden of myasthenia gravis: A systematic literature review.

BACKGROUND/OBJECTIVES: While the clinical manifestations of myasthenia gravis (MG) are well understood, its humanistic impact is not. The objective of this systematic literature review (SLR) was to provide a comprehensive understanding of the humanistic burden of MG with regards to psychological symptoms and health-related quality of life (HRQoL) according to patients and caregivers. METHODS: A systematic search was conducted on December 27, 2019, in MEDLINE and Embase to identify English-language studies that were published from January 1, 2009-December 27, 2019 and presented relevant information on the humanistic burden among adults with MG and their caregivers. Title/abstract and full-text screening was performed by two investigators, with any discrepancies resolved by a third investigator. RESULTS: Sixty-seven publications were included in the SLR. Compared with the general population, patients with MG experienced worse HRQoL. Studies reporting on psychological symptoms of MG, including depression, anxiety, fatigue, and sleep, were heterogeneous in terms of the scales and instruments used to assess patients, as well as the patient populations themselves. However, in general those with more severe symptoms and hospitalization days had worse depression and anxiety, and fatigue and sleep improved with disease remission and/or improvement. Scores were worse for females compared with males and where evaluated, HRQoL scores generally improved following treatment. CONCLUSION: While the literature demonstrates that symptoms associated with MG get better with disease improvement and remission, additional options in efficacious therapy that adequately address the disease-related symptoms and also improve HRQoL may contribute to beneficial outcomes in a greater number of patients with MG.

Intestinal failure: the evolving demographic and patient outcomes on home parenteral nutrition.

AIM: We performed this study to examine and understand the evolving demographics and changing outcomes of intestinal failure (IF) and its implications for healthcare delivery. METHOD: We conducted a retrospective analysis of outcome data of children on home parenteral nutrition (HPN), over a 15-year period. RESULTS: A total of 31 patients received HPN: 15 for short bowel syndrome (SBS), eight neuromuscular disease (NMD) and eight for other causes. The HPN prevalence increased from 1.54 per million children in 2000 to 21.5 in 2016. The outcomes over last 5 years were better than those of previous 10 years. The rate of catheter-related bloodstream infection (CRBSI) had fallen from 4 to 1.3 and IF liver disease (IFALD) from 20% to 7.7%. The aetiology changed over years from SBS being the main cause to NMD contributing 43% to the total in 2016. This was especially relevant as NMD was associated with greater numbers of IFALD (38% vs 6.7%), CRBSI (1.51 vs 0.64/1000 PN days) and mortality. CONCLUSION: The outcome of long-term parenteral nutrition (PN) has improved. The increasing number of patients with NMD, coupled with their higher burden of care, results in an increasing health care burden, and the planning of intestinal rehabilitation services needs to reflect this.

APPLICATION OF PHARMACEUTICAL KNOWLEDGE TO THE UNCONVENTIONAL USE OF A RARELY USED ANAESTHETIC AGENT.

CASE SUMMARY: A 6 yr old 45 kg child with severe Cushinoid features was admitted to PICU with probable hypertensive encephalopathy. She presented with increasing headaches, vomiting and seizures becoming unresponsive with a GCS of 3. She was profoundly hypertensive and her cortisol levels were significantly elevated (>2000 nmol/L). Rapid reduction in cortisol levels was required to stabilise her condition prior to surgery. Etomidate is the only readily available intravenous preparation which reliably suppresses adrenocortical function. A continuous infusion was started at 2.5 mg/hr and escalated to 3.5 mg/hr to reduce cortisol levels to 200 nmol/L. Cortisol levels were monitored after 1, 2, 4, 8, 12 and 24 hr on starting and at regular intervals subsequently. Hydrocortisone 20 mg/m2/24 hr was introduced to balance the adrenal suppression and optimise cortisol levels to 200-800 nmol/L. Mineralocorticoid replacement with fludrocortisone became necessary, together with significant electrolyte replacement therapy. Surgery was delayed due to sepsis, and block and replace therapy was continued for a period of 3 weeks. During this time she experienced minimal sedative effects from the etomidate. PHARMACY CONTRIBUTION: Advice was given on the potential toxicity of pharmaceutical excipients. The aqueous formulation of etomidate contains propylene glycol and prolonged infusion can result in significant intake. Calculations revealed an intake of 350 mg/kg/day for this child with an infusion of 2.5 mg/hr etomidate. The WHO limit is 25 mg/kg/day when propylene glycol is used as a food additive.1 An acceptable limit for intravenous exposure has not been established. Children under 4 years have limited ability to metabolise propylene glycol and accumulation can occur. Potential toxicity includes hyperosmolality, metabolic acidosis, nephrotoxicity, arrhythmias and CNS toxicity. To obviate these risks, the alternative lipid formulation of etomidate was obtained. Blood samples were subsequently reported to be lipaemic and concerns were raised about the lipid load of this formulation. Calculations revealed that 0.3-0.5 g/kg/day lipid was being infused, which is significantly less than parenteral nutrition would provide. It is possible that blood samples were withdrawn from the line infusing etomidate resulting in lipaemia, but it is also likely that hypertriglyceridaemia was a result of her underlying condition.The pharmacist was involved in many other aspects of this child's care including advice on intravenous access, infusion preparation, drug compatibility and stability issues, electrolyte management and dosing of various drugs in obesity. OUTCOME: An ACTH secreting thymic tumour was resected. Hydrocortisone doses were adjusted perioperatively to cover the stress of surgery, and subsequently weaned post-operatively. Complete resection was not achieved and further block and replace therapy was used prior to bilateral adrenalectomy, followed by chemotherapy and radiotherapy. LESSONS TO BE LEARNT: Pharmacists should evaluate the potential toxicity of excipients in medication, particularly when formulations are given by an unlicensed method of administration in children. Other parenteral products with a significant propylene glycol load include lorazepam, phenobarbital, phenytoin and co-trimoxazole.

Bacterial Manipulation of NK Cell Regulatory Activity Increases Susceptibility to Listeria monocytogenes Infection.

Natural killer (NK) cells produce interferon (IFN)-γ and thus have been suggested to promote type I immunity during bacterial infections. Yet, Listeria monocytogenes (Lm) and some other pathogens encode proteins that cause increased NK cell activation. Here, we show that stimulation of NK cell activation increases susceptibility during Lm infection despite and independent from robust NK cell production of IFNγ. The increased susceptibility correlated with IL-10 production by responding NK cells. NK cells produced IL-10 as their IFNγ production waned and the Lm virulence protein p60 promoted induction of IL-10 production by mouse and human NK cells. NK cells consequently exerted regulatory effects to suppress accumulation and activation of inflammatory myeloid cells. Our results reveal new dimensions of the role played by NK cells during Lm infection and demonstrate the ability of this bacterial pathogen to exploit the induction of regulatory NK cell activity to increase host susceptibility.

Nitric oxide increases susceptibility of Toll-like receptor-activated macrophages to spreading Listeria monocytogenes.

Toll-like receptor (TLR) stimulation activates macrophages to resist intracellular pathogens. Yet, the intracellular bacterium Listeria monocytogenes (Lm) causes lethal infections in spite of innate immune cell activation. Lm uses direct cell-cell spread to disseminate within its host. Here, we have shown that TLR-activated macrophages killed cell-free Lm but failed to prevent infection by spreading Lm. Instead, TLR signals increased the efficiency of Lm spread from "donor" to "recipient" macrophages. This enhancement required nitric oxide (NO) production by nitric oxide synthase-2 (NOS2). NO increased Lm escape from secondary vacuoles in recipient cells and delayed maturation of phagosomes containing membrane-like particles that mimic Lm-containing pseudopods. NO also promoted Lm spread during systemic in vivo infection, as shown by the fact that inhibition of NOS2 with 1400W reduced spread-dependent Lm burdens in mouse livers. These findings reveal a mechanism by which pathogens capable of cell-cell spread can avoid the consequences of innate immune cell activation by TLR stimuli.

Ten-year experience of home parenteral nutrition in a single centre.

AIM: Recent data are scarce on the provision of home parenteral nutrition (HPN) in children from the UK but would help to commission intestinal failure services. Our aim was to describe 10 years of HPN experience in our centre, which serves a population of 650,000 children. METHODS: Outcome and complication data were collected retrospectively from hospital records of children receiving HPN from April 2001. Data from other centres were used to compare complications and outcomes in the provision of HPN. RESULTS: Nineteen children (12 females) received 10,213 days (28 years) of HPN. In this group, incidence of blood culture positive sepsis was four episodes/1000 days PN. Two children had early intestinal failure-associated liver disease. Of the 19, seven still receive HPN at our centre, six survived PN, three were transferred to other services while still on HPN and three died. CONCLUSION: Outcome and complication data for HPN from a single UK regional paediatric centre are similar to larger centres. These data provide recent evidence of the disease burden of HPN, which are important for the commissioning of intestinal failure services.

IgG autoantibodies against deposited C3 inhibit macrophage-mediated apoptotic cell engulfment in systemic autoimmunity.

Defective clearance of apoptotic cells has been shown in systemic lupus erythematosus (SLE) and is postulated to enhance autoimmune responses by increasing access to intracellular autoantigens. Until now, research has emphasized inherited rather than acquired impairment of apoptotic cell engulfment in the pathogenesis of SLE. In this study, we confirm previous results that efficient removal of apoptotic cells (efferocytosis) is bolstered in the presence of wild-type mouse serum, through the C3 deposition on the apoptotic cell surface. In contrast, sera from three mouse models of SLE, Mer(KD), MRL(lpr), and New Zealand Black/WF1 did not support and in fact actively inhibited apoptotic cell uptake. IgG autoantibodies were responsible for the inhibition, through the blockade of C3 recognition by macrophages. Consistent with this, IgG removal reversed the inhibitory activity within autoimmune serum, and purified autoimmune IgG blocked both the detection of C3 on apoptotic cells and C3-dependent efferocytosis. Sera from SLE patients demonstrated elevated anti-C3b IgG that blocked detection of C3 on apoptotic cells, activity that was not found in healthy controls or patients with rheumatoid arthritis, nor in mice prior to the onset of autoimmunity. We propose that the suppression of apoptotic cell disposal by Abs against deposited C3 may contribute to increasing severity and/or exacerbations in SLE.

Tumor-targeted, systemic delivery of therapeutic viral vectors using hitchhiking on antigen-specific T cells.

Antigen-specific T cells circulate freely and accumulate specifically at sites of antigen expression. To enhance the survival and targeting of systemically delivered viral vectors, we exploited the observation that retroviral particles adhere nonspecifically, or 'hitchhike,' to the surface of T cells. Adoptive transfer of antigen-specific T cells, loaded with viruses encoding interleukin (IL)-12 or Herpes Simplex Virus thymidine kinase (HSVtk), cured established metastatic disease where adoptive T-cell transfer alone was not effective. Productive hand off correlated with local heparanase expression either from malignant tumor cells and/or as a result of T-cell activation by antigen, providing high levels of selectivity for viral transfer to metastatic tumors in vivo. Protection, concentration and targeting of viruses by adsorption to cell carriers represent a new technique for systemic delivery of vectors, in fully immunocompetent hosts, for a variety of diseases in which delivery of genes may be therapeutically beneficial.

Use of blood outgrowth endothelial cells as virus-producing vectors for gene delivery to tumors.

Cell-based delivery of therapeutic viruses has potential advantages over systemic viral administration, including attenuated neutralization and improved viral targeting. One of the exciting new areas of investigation is the potential ability of endothelial-lineage cells to deliver genes to the areas of neovascularization. In the present study, we compared two types of endothelial-lineage cells [outgrowth endothelial cells (OECs) and culture-modified mononuclear cells (CMMCs), also known as "endothelial progenitor cells"] for their ability to be infected with adenovirus and to home to the areas of neovascularization. Both cell types were isolated from peripheral blood of healthy human donors and expanded in culture. We demonstrate that OECs are more infectable and home better to tumors expressing VEGF on systemic administration. Furthermore, we used an adenoviral/retroviral chimeric system to convert OECs to retrovirus-producing cells. When injected systemically into tumor-bearing mice, OECs retain their ability to produce retrovirus and infect surrounding tumor cells. Our data demonstrate that OECs could be efficient carriers for viral delivery to areas of tumor neovascularization.