Structural characterization of PHOX2B and its DNA interaction shed light on the molecular basis of the +7Ala variant pathogenicity in CCHS.

An expansion of poly-alanine up to +13 residues in the C-terminus of the transcription factor PHOX2B underlies the onset of congenital central hypoventilation syndrome (CCHS). Recent studies demonstrated that the alanine tract expansion influences PHOX2B folding and activity. Therefore, structural information on PHOX2B is an important target for obtaining clues to elucidate the insurgence of the alanine expansion-related syndrome and also for defining a viable therapy. Here we report by NMR spectroscopy the structural characterization of the homeodomain (HD) of PHOX2B and HD + C-terminus PHOX2B protein, free and in the presence of the target DNA. The obtained structural data are then exploited to obtain a structural model of the PHOX2B-DNA interaction. In addition, the variant +7Ala, responsible for one of the most frequent forms of the syndrome, was analysed, showing different conformational proprieties in solution and a strong propensity to aggregation. Our data suggest that the elongated poly-alanine tract would be related to disease onset through a loss-of-function mechanism. Overall, this study paves the way for the future rational design of therapeutic drugs, suggesting as a possible therapeutic route the use of specific anti-aggregating molecules capable of preventing variant aggregation and possibly restoring the DNA-binding activity of PHOX2B.

Semaglutide in Cardiometabolic Diseases: SELECTing the Target Population.

Cardiovascular diseases remain the main cause of death and disability worldwide. Despite the tremendous improvement in pharmacological, minimally invasive and rehabilitative strategies, global deaths due to cardiovascular diseases are still increasing. Additional risk factors have been recently proposed, and thanks to scientific progress, novel drugs for the control of the main risk factors focusing on the cardiometabolic pathways have been identified. Glucagon-like peptide-1 (GLP-1) receptor agonists represent an innovative step in the management of patients affected by type 2 diabetes mellitus. In addition to their significant efficacy on glycemic homeostasis, some members of this class of drugs have indications in the treatment of obesity. Furthermore, accumulated evidence in the literature has finally suggested a protective role in cardiovascular health. The possible role of GLP-1R agonist drugs (GLP-1RAs) on the mechanisms underlying chronic inflammation and the almost ubiquitous distribution of GLP-1 receptors could explain the enormous versatility of these drugs. Semaglutide is a GLP-1RA recently proven to be effective in cardiovascular outcomes. In the present article, we will review the available data on semaglutide in light of the most recent publications to better characterize the target population achieving cardiovascular benefits.

Structural and dynamical determinants of a ß-sheet-enriched intermediate involved in amyloid fibrillar assembly of human prion protein.

The conformational conversion of the cellular prion protein (PrPC) into a misfolded, aggregated and infectious scrapie isoform is associated with prion disease pathology and neurodegeneration. Despite the significant number of experimental and theoretical studies the molecular mechanism regulating this structural transition is still poorly understood. Here, via Nuclear Magnetic Resonance (NMR) methodologies we investigate at the atomic level the mechanism of the human HuPrP(90-231) thermal unfolding and characterize the conformational equilibrium between its native structure and a ß-enriched intermediate state, named ß-PrPI. By comparing the folding mechanisms of metal-free and Cu2+-bound HuPrP(23-231) and HuPrP(90-231) we show that the coupling between the N- and C-terminal domains, through transient electrostatic interactions, is the key molecular process in tuning long-range correlated µs-ms dynamics that in turn modulate the folding process. Moreover, via thioflavin T (ThT)-fluorescence fibrillization assays we show that ß-PrPI is involved in the initial stages of PrP fibrillation, overall providing a clear molecular description of the initial phases of prion misfolding. Finally, we show by using Real-Time Quaking-Induced Conversion (RT-QuIC) that the ß-PrPI acts as a seed for the formation of amyloid aggregates with a seeding activity comparable to that of human infectious prions.

Effects of Aqueous-Supplementing Artificial Tears in Wearers of Biweekly Replacement Contact Lenses vs Wearers of Daily Disposable Contact Lenses.

PURPOSE: To compare the effects of artificial tears (ATs) in wearers of biweekly replacement silicone hydrogel contact lenses (BW-Ws) and wearers of daily disposable contact lenses (DD-Ws) of the same material. MATERIALS AND METHODS: The aqueous-supplementing ATs, OPTOyalA and OPTOidro, were assigned to be used for 2 weeks to healthy and young subjects: 1) 20 (8 and 12, respectively) BW-Ws wearing silicone hydrogel somofilcon A CLs (Clariti Elite), 2) 18 (9 and 9, respectively) DD-Ws wearing silicone hydrogel somofilcon A CLs (Clarity 1 Day), and 3) a control group of 33 (16 and 17, respectively) N-Ws. Ocular symptoms and comfort, tear volume and stability, and ocular surface condition were assessed by Ocular Surface Disease Index (OSDI), 5-Item Dry Eye Questionnaire (DEQ5), tear meniscus height (TMH), non-invasive tear break-up time (NIBUT), and evaluation of ocular redness (OR). The assessment was performed before and after 15 days of use of the ATs in the 3 groups (BW-Ws, DD-Ws, and N-Ws). RESULTS: No clear significant difference was noted in symptoms and signs between OPTOyalA and OPTOidro irrespectively of the group of people studied. ATs use for 15 days produced a significant improvement in DEQ5 and OR in DD-Ws (Δ=-34%, p=0.006; Δ=-23%, p<0.001) and in N-Ws (Δ=-21%, p=0.001; Δ=-10%, p=0.006) but not in BW-Ws (Δ=-5%, p=0.072; Δ=-2%, p=0.257). No significant change was noted for TMH. CONCLUSION: In young and healthy subjects, the aqueous-supplementing effect of the ATs under consideration is more a rinsing and tear replacem ent effect than an increase in tear volume, and it produces an improvement of the eye redness and ocular symptoms. Contact lens wear influenced the effectiveness of ATs in a way which is correlated with the CL replacement schedule.

Smell and Taste Impairment After Total Laryngectomy.

OBJECTIVE: Aim of this observational study is the evaluation of olfactory and gustatory impairments in laryngectomized long-term survivors compared to control subjects. Correlation between smell and taste alterations, age, and previous adjuvant treatments in laryngectomees was investigated. METHODS: Fifty control subjects and 50 patients who underwent total laryngectomy for advanced laryngeal carcinoma were evaluated. All subjects underwent symptoms evaluation, oropharyngeal exam, endoscopic fiberoptic nasal examination, and Taste Strips and Sniffin' Sticks tests. RESULTS: Hyposmia was reported by all laryngectomees and hypogeusia by 54% of patients. Sniffin' Sticks and Taste Strips tests demonstrated a statistically significant difference between controls and laryngectomees regarding olfactory threshold, odor discrimination and identification, Threshold Discrimination Identification (TDI) score, and sour, salty, and gustatory Total Taste score ( P < .05). Multivariate analysis for Total Taste score in laryngectomees showed a statistically significant correlation with aging, having an odds ratio of 0.127 for age ≥65 years, but not with TDI score, radiotherapy, and follow-up time, whereas multivariate analysis for TDI score demonstrated no correlation with radiotherapy, age, and follow-up time. CONCLUSIONS: Total laryngectomy determines olfactory and gustatory impairments that should be taken into account in clinical practice. Relationships between sensorial alterations, aging, follow-up period, and adjuvant treatments should be further evaluated in prospective studies.

Nasal and Tracheal Cytological Changes After Total Laryngectomy in Long-Term Survivors.

OBJECTIVE: Complete separation of upper and lower respiratory tract after total laryngectomy results in permanent effects on nasal cavities and tracheo-bronchial airways. Aim of this study is evaluating nasal and tracheal cytological alterations of mucosa in laryngectomy long-term survivors, analyzing the feasibility of scraping for cytological examination of tracheal mucosa. METHODS: Twenty-five laryngectomy patients underwent symptoms' evaluation, endoscopic fiber optic examination, prick tests, and nasal and tracheal scraping for cytological exam. Twenty-five healthy subjects underwent the same assessment, except for tracheal scraping. Eleven laryngectomy patients accepted inferior turbinate biopsy for histological examination. RESULTS: Nasal cytological analysis demonstrated mucous cell metaplasia in 20% of laryngectomized patients, but it was absent in all healthy subjects; no squamous cell metaplasia was found in both groups. In 15 patients (60%), bacteria were present, without inflammatory infiltrate. Tracheal cytological analysis demonstrated a quite high rate of squamous cell metaplasia (24%), neutrophilic infiltrate (32%), and presence of bacteria (40%). Histological examination of inferior turbinate showed submucosal stromal fibrosis in all patients and submucosal inflammatory infiltrate in 1 case (9%). CONCLUSION: Nasal cavities and trachea of laryngectomy patients undergo long-term cytological and histological changes of mucosa and submucosa, probably due to airflow modifications.

Liposarcoma of Hypopharynx and Esophagus: a Unique Entity?

PURPOSE: Liposarcoma is the most common soft tissue sarcoma in adults. It represents approximately 20 % of all mesenchymal malignancies. It most frequently involves retroperitoneum, trunk, and extremities. Hypopharyngeal and esophageal localization of liposarcoma is extremely rare. METHODS: We performed a systematic review of literature and reported 26 and 33 cases of hypopharyngeal and esophageal liposarcoma. We analyzed natural history, imaging features, histology, treatment, and prognosis, with a specific focus to similarities and differences between tumors of hypopharynx and esophagus. RESULTS: Hypopharyngeal and esophageal liposarcomas have more similarities than differences. Incidence has a peak at 6th and 7th decades. The diagnostic procedures are barium swallow, endoscopic examination, and CT/MR imaging. Well-differentiated liposarcoma represents the most frequent histological subtype. Surgical excision is the main treatment. Endoscopic resection can be useful for pedunculated tumors of hypopharynx and cervical esophagus. Differences between hypopharyngeal and esophageal liposarcoma are represented by local recurrence rate (greater for hypopharyngeal tumors), number of giant tumors, and time to recurrence (greater for esophageal tumors). Finally, liposarcomas of distal esophagus need more extended approaches. CONCLUSIONS: Liposarcomas of hypopharynx and cervical esophagus could be considered a unique pathological entity, with similar features and treatment options. Survival rate is dependent on histological type and location. Local recurrence is common, especially for hypopharyngeal liposarcoma, while the risk of lymph node or distant metastasis is very low. Patients should undergo regular examinations to rule out local recurrence, also for a long time, especially for esophageal tumors.

Rare Giant Pedunculated Liposarcoma of the Hypopharynx: Case Report and Review of Literature.

INTRODUCTION: Liposarcoma is considered the most common soft tissue sarcoma in adults. It represents approximately 20 % of all mesenchymal malignancies, and most frequently it involves the retroperitoneum, trunk, and extremities. Hypopharyngeal localization of liposarcoma is extremely rare. METHODS: We report a new rare case of giant pedunculated liposarcoma arising from the left antero-lateral wall of the hypopharyngeal-esophageal junction, and we present a complete review of the literature. RESULTS: An 81-year-old man presented with a 5-month history of dysphagia and 30-kg weight loss, due to a giant pedunculated liposarcoma of the hypopharynx, which is resected with cervical approach. CT scan imaging revealed a 25-cm-long pedunculated heterogeneous mass with fat-like density originating from the anterior wall of hypopharyngeal-esophageal junction protruding into the lumen. The polypoid mass was identified as well as the stalk, and it was completely delivered through the cervical incision. Histopatological examination showed a dedifferentiated liposarcoma, without positive or close margins. No further chemoradiation therapy was performed due to the patient's age, comorbidities, negative margins, and absence of distant metastases. Dysphagia solved 1 month after surgery. No evidence of tumor recurrence was seen in the 12 months following surgery. CONCLUSIONS: When base of the tumor is located in hypopharynx or cervical portion of the esophagus, and tumor is not aggressive, cervical approach is better, irrespective of the tumor size, except for cases in which an endoscopic approach is feasible.