Effects of cryotherapy on the maxillary antrostomy patency in a rabbit model of chronic rhinosinusitis

The Impact of Spray Cryotherapy on Lesion-Induced Osteitis in a New Murine Experimental Model

Background and Objectives: Endoscopic sinus surgery is considered the gold management strategy for difficult-to-treat chronic rhinosinusitis. The inflammatory bony process is incriminated as being involved in the unfavorable evolution and recurrence of the disease. Osteitis is significantly increased in patients that have been previously submitted to surgery, and it is more often present in patients with extended radiological disease and in patients undergoing revision surgery. The aim of the research is to demonstrate the presence of inflammations and neo-osteogenesis associated with nasal mucosal surgical injury and the correlation between their severity and to evaluate the efficacy of low-pressure spray cryotherapy in reducing inflammation and bone remodeling. Materials and Methods: The experimental murine model was conducted over a period of 80 days and included a total of 60 adult female Wistar rats, with three periods of withdrawal of 20 individuals each from the experiment. After inducing a bilateral mechanical injury by brushing, low-pressure spray cryotherapy application was performed unilaterally, and tissue samples were prepared specifically for histological analysis. The scores for inflammation and osteitis were compared over time and between the two nasal fossae. Results: Osteitis and inflammation were induced by a simple mucosal brushing lesion, similar to surgical injury. We identified the presence of inflammation in 95% of the specimens, and it was present over time. Moreover, criteria for bone remodeling were clearly highlighted in a percentage of 72% of the specimens. There was a direct correlation between the severity of inflammation and neo-osteogenesis, with a statistical significance of p = 0.050. Low-pressure spray cryotherapy was safe and effective in reducing inflammation (p = 0.020) and osteitis (p = 0.000) with a safety profile. Conclusions: Low-pressure cryotherapy reduces the severity of mucosal inflammation and osteitis in lesion-induced neo-osteogenesis.

Unilateral Intervention in the Sinuses of Rabbits Induces Bilateral Inflammatory and Microbial Changes

Background

Chronic rhinosinusitis (CRS) is a globally prevalent inflammatory condition of the paranasal sinuses which severely impairs patients' quality of life. An animal model of unilateral sinusitis by transient sinus occlusion has been described previously in rabbits. The aim of this study was to characterise the sinusitis rabbit model by investigating temporal and bilateral changes in the bacterial community and mucosal inflammation.

Methods

Development of sinusitis was achieved by endoscopically placing Merocel ^® , a sterile nasal packing material, in the left middle meatus of six New Zealand white rabbits for four weeks. After a total period of 14 weeks, rabbits were assessed for sinusitis by endoscopic examination, magnetic resonance imaging (MRI) and histology. Swabs from the left and right middle meatus were obtained for bacterial community analysis at three time points (week 0, week 4, week 14) during the study.

Results

Endoscopic evaluation showed unilateral inflammation in all animals examined after the 4-week blocking period and at week 14. Notably, inflammatory changes were also seen in the contralateral sinus of all animals at week 4. MRI images demonstrated unilateral sinus opacification at week 4 in two rabbits, and partial unilateral sinus opacification at week 14 in one rabbit only. Histological analyses revealed substantial spatial heterogeneity of mucosal inflammation with inconsistent findings across all animals. No significant differences in mucosal inflammatory markers (such as goblet cell hyperplasia, epithelial denudation and oedema) could be identified between nostrils at week 14. The bacterial community in the rabbit sinuses was heavily dominated by Helicobacter at week 0 (baseline). At the end of the blocking period (week 4), bacterial alpha and beta diversity were significantly increased in both nostrils. The bacterial community composition at week 14 had primarily returned to baseline, reflecting the endoscopic and radiological results.

Conclusion

This study reaffirmed the ability for development of sinusitis without inoculation of any pathogens in a rabbit model. We were able to demonstrate bilateral sinonasal mucosal inflammation, by inducing unilateral sinus blockage, which resulted in significant changes to the sinonasal bacterial community. These findings may explain some of the clinical observations seen in CRS and warrant further research to reveal potential implications for its therapeutic management.

The Role of Mesenchymal Stem Cells in the Treatment of a Chronic Rhinosinusitis-An In Vivo Mouse Model

Objectives/Hypothesis: It is acknowledged that the treatment of chronic rhinosinusitis (CRS) represents an important challenge for rhinology and for social and economic life. At present, one of the most common treatments for CRS is represented by local corticosteroids followed by endoscopic sinus surgery (ESS). Starting from the example of the mesenchymal stem cell’s (MSC) capacity to migrate and to modulate a real response in the nasal mucosa of an allergic rhinitis mouse model, we try to obtain a response in a CRS mouse model, using MSC derived by adipose tissue. The aim of this study is to demonstrate that the MSC can be used in CRS treatment and could change its priorities. Methods: Seventy female mice (6 MSC donor mice) were randomized in two stages of study, 32 Aspergillus fumigatus (Af) exposure mice (20 for histological comparison to 1st control mice and 12 for MSC administration, to CRS/MCS model) and 32 control mice (20 for histological comparison to CRS model and 12 for MSC administration and histological control to MSC model); in the first stage, the Aspergillus fumigatus (Af) CRS mouse model was targeted, in this section were included 64 (n = 32) mice (treated and control group). In order to assess the inflammation level (histological analysis), the animals were euthanized; in the second stage MSCs (1 × 10⁶/animal) were administered intravenously to a total of 24 (n = 24) mice (12 mice from the exposed group and 12 mice from the second control group). Results: After 12 weeks of Af intranasal instillation, the inflammation parameters evaluated indicated a severe diffuse chronic inflammation, associated with diffuse severe hyperplasia and mature diffuse squamous metaplasia. The MSCs’ injection via the ophthalmic vein induced important histopathological changes in the CRS experimental group, starting with the presence of MSCs in all samples and continuing with the important degenerative character of inflammation. Conclusions: MSC administration demonstrated a real improvement of CRS evolution on the CRS mouse model.

The Effect of Spray Cryotherapy on Microbial Biofilms in Chronic Rhinosinusitis

PURPOSE OF REVIEW

Microbial biofilms seem to play an active role in the pathogenesis of chronic rhinosinusitis (CRS). They represent an adaptive defense resource enabling resistance to antibiotics and host defense mechanisms. Biofilms are thought to be accountable for refractory cases of sinusitis by perpetuating local inflammation. The objective of this study was to assess the effectiveness of spray cryotherapy as a biofilm disruption agent in CRS in an in vitro model.

RECENT FINDINGS

A total of 23 patients with CRS undergoing endoscopic sinus surgery (ESS) were included. Rhinosinusal mucosa samples were harvested. Half of sample was left intact while the other half was treated with spray cryotherapy, so patients served as their own witnesses. Subsequently, they were processed to hematoxylin-eosin (HE) and toluidine blue (TB) staining and analyzed by light microscopy. Biofilms were detected in 17 of 23 patients with CRS. Staining by HE showed strong correlation with the results of TB staining protocol. The in vitro CRS study demonstrated that spray cryotherapy removed polymicrobial biofilms from the mucosa surface in 70.6% of cases and induced important structural changes in the remaining samples. Thus far, cryotherapy has proven to be a reliable method for the disruption of microbial biofilms in CRS with nasal polyps, in vitro conditions. Spray cryotherapy could be a considerable benefit in the management of recalcitrant CRS.

Outcome of spray cryotherapy plus functional endoscopic sinus surgery on management of healing in nasal polyposis

BACKGROUND

Nasal Polyposis is a benign tumor in nasal or paranasal mucosa, which confronts difficulties in management of healing after treatments with surgery. The aim of this study was to evaluate the effects of Spray Cryotherapy (SCT) on management of healing in patients with nasal polyposis who undergone functional endoscopic sinus surgery.

METHODS

In this prospective, clinical trial study, we investigated on 40 patients with nasal polyposis that had indication for functional endoscopic sinus surgery. Patients were divided randomly into two parallel group; cryotherapy (with SCT) and placebo (without SCT). Evaluation of healing after surgery was evaluated with Lund-Mackay and The Sino-nasal outcome test (SNOT-22)-22 scores.

RESULT

Postoperatively, Lund-Mackay and SNOT-22 scores were significantly decreased in both groups, however these scores were significantly lower in cryotherapy group in comparison with placebo group. Also there were no reported serious side effects in both groups.

CONCLUSION

In this paper, we concluded that usage of SCT is an effective and safe method on management of healing and develops recovery rates in patients with nasal polyposis undergoing functional endoscopic sinus surgery.

Animal Models in CRS and Pathophysiologic Insights Gained: A Systematic Review

OBJECTIVE

Chronic rhinosinusitis (CRS) is a multifactorial inflammatory disease. In particular, CRS with eosinophilic features and/or nasal polyps (NPs) is often recalcitrant to current treatment; thus, appropriate animal models are mandatory to elucidate the pathogenesis of CRS and develop novel and efficient treatment modalities. The author reviewed the recently proposed animal models in CRS and discussed the pathophysiologic insights gained. Data Sources: Articles in the English language referenced in MEDLINE/PubMed from the year 2006 onward (for last 10 years). Review Methods: Review of the literature regarding animal models and related pathologic insights in CRS.

RESULTS

Mouse, rabbit, and sheep models of CRS have been used for studying the pathogenesis of CRS. Most of researchers adopted animal models of CRS to prove any molecular mechanisms or therapeutic efficacy. In vitro or human findings and related hypothesis were evaluated in vivo using these models. In addition, novel therapeutic candidates for CRS with or without NP have been applied to animal models.

CONCLUSION

Animal models have elicited insights into the pathogenesis of CRS and also have been useful in testing new treatment modalities. Although there are still clear limitations in the animal studies, newly proposed or revised animal models would be helpful to understand the exact pathophysiology of CRS.

Hepatocyte Growth Factor Gene-Modified Mesenchymal Stem Cells Augment Sinonasal Wound Healing

This study was designed to investigate the effects of hepatocyte growth factor (HGF) transgenic mesenchymal stem cells (HGF-MSCs) on wound healing in the sinonasal mucosa and nasal epithelial cells (NECs). We also sought to determine whether HGF-MSCs and MSCs can migrate into the injured mucosa and differentiate into ciliated cells. Human HGF-overexpressing umbilical cord MSCs (hHGF-UCMSCs) were established, and upregulation of hHGF expression was confirmed by real-time PCR (RT-PCR) and enzyme-linked immunosorbant assay (ELISA). To investigate the paracrine effect of human MSCs (hMSCs) on nasal epithelial repair, hMSC- and HGF-MSC-conditioned media (CM) were used in NEC proliferation assays and in an in vitro scratch-wound repair model. The in vivo sinonasal wound-healing model was established, and all enrolled rabbits were randomly assigned to four groups: the GFP-MSC group, the HGF-MSC group, the Ad-HGF group, and the surgery control group. The average decreased diameter was recorded, and the medial wall of the maxillary sinus was removed for histological analysis and scanning electron microscopy. Collagen deposition in the wound tissue was detected via Masson trichrome (M&T) staining. The distribution of MSCs and HGF-MSCs was observed by immunofluorescence. MSCs improved nasal wound healing both in vivo and in vitro. HGF overexpression in MSCs augmented the curative effects. Reduced collagen deposition and transforming growth factor beta1 (TGF-β1) expression were detected in the HGF-MSC group compared with the MSC-, Ad-HGF-, and phosphate-buffered saline-treated groups based on M&T staining and ELISA. The enhanced therapeutic effects of HGF-MSCs were accompanied by decreased level of the fibrogenic cytokine TGF-β1. In addition, both HGF-MSCs and MSCs can migrate to the injured mucosa and epithelial layer.

Efficiency of cryotherapy in avoiding myringotomy closure in rats

Myringotomy and ventilation tube placement is an office-based procedure and represents the treatment of choice for middle ear effusions and for transtympanic drug administration. The aim of our study was to study the efficiency of low-pressure spray cryotherapy on protraction of patency time of myringotomies in rats. Bilateral myringotomies were performed with cold instruments. Afterward, one ear in each rat was randomly assigned for liquid nitrogen treatment of the perforated eardrum. Myringotomy patency was recorded daily and histological analysis of the eardrums was performed. In the myringotomy group patency time was 4.75 ± 2.93 days, while in the cryotherapy group was 11.01 ± 4.87 days. The difference is statistically significant: Student t test, p < 0.00001, 95 % CI (-8.82; -3.67). Moreover, according to Kaplan-Meier method, myringotomy survival is significantly longer in the cryotherapy group. The healing processes of the cryotreated eardrums last longer and the patency of myringotomy was longer as compared to untreated myringotomies.