Persistent post-COVID-19 smell loss is associated with immune cell infiltration and altered gene expression in olfactory epithelium

SARS-CoV-2 causes profound changes in the sense of smell, including total smell loss. Although these alterations are often transient, many patients with COVID-19 exhibit olfactory dysfunction that lasts months to years. Although animal and human autopsy studies have suggested mechanisms driving acute anosmia, it remains unclear how SARS-CoV-2 causes persistent smell loss in a subset of patients. To address this question, we analyzed olfactory epithelial samples collected from 24 biopsies, including from nine patients with objectively quantified long-term smell loss after COVID-19. This biopsy-based approach revealed a diffuse infiltrate of T cells expressing interferon-γ and a shift in myeloid cell population composition, including enrichment of CD207+ dendritic cells and depletion of anti-inflammatory M2 macrophages. Despite the absence of detectable SARS-CoV-2 RNA or protein, gene expression in the barrier supporting cells of the olfactory epithelium, termed sustentacular cells, appeared to reflect a response to ongoing inflammatory signaling, which was accompanied by a reduction in the number of olfactory sensory neurons relative to olfactory epithelial sustentacular cells. These findings indicate that T cell-mediated inflammation persists in the olfactory epithelium long after SARS-CoV-2 has been eliminated from the tissue, suggesting a mechanism for long-term post-COVID-19 smell loss.

Rapid tissue prototyping with micro-organospheres

In vitro tissue models hold great promise for modeling diseases and drug responses. Here, we used emulsion microfluidics to form micro-organospheres (MOSs), which are droplet-encapsulated miniature three-dimensional (3D) tissue models that can be established rapidly from patient tissues or cells. MOSs retain key biological features and responses to chemo-, targeted, and radiation therapies compared with organoids. The small size and large surface-to-volume ratio of MOSs enable various applications including quantitative assessment of nutrient dependence, pathogen-host interaction for anti-viral drug screening, and a rapid potency assay for chimeric antigen receptor (CAR)-T therapy. An automated MOS imaging pipeline combined with machine learning overcomes plating variation, distinguishes tumorspheres from stroma, differentiates cytostatic versus cytotoxic drug effects, and captures resistant clones and heterogeneity in drug response. This pipeline is capable of robust assessments of drug response at individual-tumorsphere resolution and provides a rapid and high-throughput therapeutic profiling platform for precision medicine.

Persistent post-COVID-19 smell loss is associated with inflammatory infiltration and altered olfactory epithelial gene expression

Most human subjects infected by SARS-CoV-2 report an acute alteration in their sense of smell, and more than 25% of COVID patients report lasting olfactory dysfunction. While animal studies and human autopsy tissues have suggested mechanisms underlying acute loss of smell, the pathophysiology that underlies persistent smell loss remains unclear. Here we combine objective measurements of smell loss in patients suffering from post-acute sequelae of SARS-CoV-2 infection (PASC) with single cell sequencing and histology of the olfactory epithelium (OE). This approach reveals that the OE of patients with persistent smell loss harbors a diffuse infiltrate of T cells expressing interferon-gamma; gene expression in sustentacular cells appears to reflect a response to inflammatory signaling, which is accompanied by a reduction in the number of olfactory sensory neurons relative to support cells. These data identify a persistent epithelial inflammatory process associated with PASC, and suggests mechanisms through which this T cell-mediated inflammation alters the sense of smell.

Decreased Antibiotic Utilization After Sinus Surgery in Cystic Fibrosis Patients With Lung Transplantation

Background

Patients with cystic fibrosis (CF) who have undergone lung transplantation frequently require hospitalizations and antibiotic treatments for respiratory tract infections. Although endoscopic sinus surgery (ESS) improves sinonasal quality of life in CF patients, it is unclear if ESS offers additional benefit in terms of antibiotics for pulmonary infection, hospitalization, and pulmonary function.

Objective

To determine whether ESS impacts antibiotic use or hospitalizations for pulmonary indications or pulmonary function in CF patients after lung transplantation.

Methods

This is a single-institution retrospective study of all patients who underwent lung transplantation for CF from 2005 to 2017. Patients who underwent ESS at least 1 year after transplant were included. Paired bivariate analyses were performed to determine whether there was a difference in the frequency and length of hospitalizations for pulmonary indications, number of antibiotic courses (intravenous and oral) for pulmonary exacerbations, and forced expiratory volume in 1 second (FEV1) slope in the 6 months before versus after ESS. Perioperative antibiotics and hospitalizations were not included in the analyses. Least squares regression was utilized to analyze FEV1 trends.

Results

A total of 20 patients underwent 36 ESS during the study period. There was significantly higher antibiotic utilization in the 6 months before ESS (0.89 ± 1.03) compared to the 6 months after ESS (0.33 ± 0.53) ( P = .002). The frequency and length of hospitalizations, FEV1 slope, and FEV1 trend before and after ESS were not significantly different.

Conclusion

Our results suggest that ESS is associated with a reduction in the frequency of antibiotic utilization for respiratory tract infections in lung transplant recipients with CF. A prospective study is needed to investigate these relationships further.

Management of epistaxis in patients with ventricular assist device: a retrospective review

Background

Patients with a ventricular assist device (VAD) are at risk for epistaxis due to the need for anticoagulation. Additionally, these patients develop acquired von Willebrand syndrome (AvWS) due to these devices. Management is complicated by the risk of thrombosis if anticoagulation is reversed. This study sought to characterize the clinical features and management of epistaxis in this high-risk population.

Methods

Retrospective review of adults with VAD and epistaxis necessitating inpatient consultation with the otolaryngology service were included.

Results

49 patients met inclusion criteria. All patients had a presumed diagnosis of AvWS. An elevated INR (> 2.0) was present in 18 patients (36.7%). Anticoagulation was held in 14 (28.6%) patients, though active correction was not necessary. Multiple encounters were required in 16 (32.7%) patients. Spontaneous epistaxis was associated with multiple encounters (p = 0.02). The use of hemostatic material was associated with a lower likelihood of bleeding recurrence (p = 0.05), whereas cauterization with silver nitrate alone was associated with a higher likelihood of re-intervention (p = 0.05). Surgery or embolization was not required urgently for any patient. Endoscopy under general anesthesia was performed for one patient electively. Mean follow up time was 16.6 months (σ = 6.3). At six months, 18 (36.7%) patients were deceased.

Conclusion

While these patients are at risk for recurrent spontaneous epistaxis, nonsurgical treatment without active correction of INR or AvWS was largely successful. Placement of hemostatic material, as opposed to cautery with silver nitrate, should be considered as a first-line treatment in this group. Multidisciplinary collaboration is critical for successful management.

Endoscopic trans-sphenoidal surgery for petroclival and clival meningiomas

Petroclival meningiomas are challenging lesions to manage independently of the selected surgical approach and are unique tumors in the type of pathological displacement of the surrounding anatomy. They also represent one of the most controversial entities with regard to approach selection, especially when deciding between an open versus endonasal route. When choosing an approach to the intradural portion of the petroclival region, the location of critical neurovascular structures relative to the lesion must be anticipated, including the abducens and trigeminal nerves. The role of the expanded endoscopic endonasal approach (EEA) in the management of ventral posterior fossa meningiomas is still restricted due to limited surgical indications in selected cases. It is a safe alternative for the rare cases of meningiomas with most part of its dural base at the midline clival region, and it may be used as solely or combination of other approaches. Thus, appropriate case selection may optimize the advantages of the approach and reduce morbidity of this complex pathology. We discuss in this review article the main advantages and limitations of the EEA for clival and petroclival meningiomas.

Middle ear packing: comparison of materials in an animal model of mucosal trauma

OBJECTIVE

To compare absorbable gelatin sponge (AGS) with an injectable esterified hyaluronic acid (EHA) as middle ear packing material after mucosal trauma.

STUDY DESIGN

Randomized, blinded, and controlled study.

SETTING

Tertiary university-based hospital.

SUBJECTS AND METHODS

Twenty-three guinea pigs underwent middle ear surgery with mucosal trauma performed on both ears and one ear packed with either EHA or AGS. Contralateral ears were used as nonpacked paired controls. Auditory brainstem response (ABR) thresholds were measured preoperatively and repeated at 1, 2, and 6 weeks postoperatively. Macroscopic and microscopic analysis measured inflammatory reaction in each group.

RESULTS

ABR threshold changes from baseline in the EHA and both control groups were minor. Threshold levels were higher in the AGS group compared with the AGS control group. This trend was seen in each frequency tested at each time interval. Macroscopic analysis showed tympanic membrane perforation was rare, effusions were common in the AGS group, mucosal edema was most frequent in the AGS group, and unabsorbed packing was usually detected in the AGS group with little EHA detectable at 6 weeks. Microscopic analysis showed normal mucosal healing in all groups. Two AGS ears demonstrated excessive middle ear packing with exuberant osteoneogenesis.

CONCLUSIONS

Middle ear function and mucosal healing after surgery occurred similarly between the EHA control group and the EHA group. In contrast, the AGS group demonstrated worse hearing and a greater level of osteoneogenesis compared with the AGS control group. These results support EHA as an alternative middle ear packing material in otologic surgery.