Advancements in physiologically based pharmacokinetic modeling for fedratinib: updating dose guidance in the presence of a dual inhibitor of CYP3A4 and CYP2C19.

PURPOSE: A physiologically based pharmacokinetic (PBPK) model for fedratinib was updated and revalidated to bridge a gap between the observed drug-drug interaction (DDI) of a single sub-efficacious dose in healthy participants and the potential DDI in patients with cancer at steady state. The study aimed to establish an appropriate dose for fedratinib in patients coadministered with dual CYP3A4 and CYP2C19 inhibitors, providing quantitative evidence to inform dosing guidance. METHODS: The original minimal PBPK model was developed using Simcyp® Simulator v17. The model was updated by substituting a single distribution rate (Qsac) with 2 separate rates (CLin/CLout) and transitioning to v20. Model parameter updates were further informed with 3 clinical studies, and 3 more studies served as independent validation data. The validated model was applied to simulate potential DDIs between fedratinib and a known dual inhibitor of CYP3A4 and CYP2C19 (fluconazole). RESULTS: Coadministration of fedratinib with fluconazole in patients was predicted to increase fedratinib exposure by < 2-fold in all simulated scenarios. For patients with cancer receiving the approved dose of fedratinib 400 mg once daily along with fluconazole 200 mg daily, the model predicted an approximate 50% increase in fedratinib exposure at steady state. CONCLUSIONS: The updated PBPK model improved description of the observed pharmacokinetics and predicted a low risk of clinically significant DDIs between fedratinib and fluconazole. The quantitative evidence serves as a primary foundation for providing dose guidance in clinical practice for the coadministration of fedratinib with dual CYP3A4 and CYP2C19 inhibitors.

The impact of statin therapy on the healing of diabetic foot ulcers: a case-control series.

BACKGROUND: Diabetic foot ulcers (DFU) are a costly complication of diabetes mellitus (DM), with significant implications for the patient and the healthcare professionals that treat them. The primary objective of this study was to evaluate if there were improved healing rates in patients with a DFU that were taking a statin medication compared to those patients with a DFU who were not taking a statin medication. Secondary outcomes assessed were correlations with wound healing or statin use on data obtained from retrospective chart review. METHODS: A case-control series was performed to obtain appropriate demographic information, comorbid conditions, laboratory values, and physical examination findings. From the time of presentation with DFU, these patients were followed for 12 weeks to evaluate for healing. Healing was defined as full epithelialization of the DFU with no further drainage. Wound healing and statin use correlation testing was then done for collected variables and each cohort. Chi square and Pearson correlation were then performed to identify any significant correlations. All p-values were two-sided, and findings were considered statistically significant at p < 0.05. RESULTS: Our study identified 109 patients, 75 patients with a DFU on statin medication and 34 patients with a DFU not on statin medication. The statin cohort was more likely to be older, less than 5-year duration of diabetes, have more comorbidities, decreased low-density lipoprotein (LDL) cholesterol, and decreased total cholesterol (p < 0.05). Among those patients taking a statin medication, 48.0% (36/75) healed their DFU within 12 weeks. Among those patients not taking a statin medication, 44.1% (15/34) healed their DFU within 12 weeks. No correlation was noted between wound healing and statin use (p = 0.7). For wound healing, a negative correlation was noted for prior minor amputations (p < 0.05). For statin use, correlations were noted for age, duration of DM, LDL cholesterol level, total cholesterol level, HTN, CAD, and HLD (p < 0.05). CONCLUSIONS: Statin medication use did not influence DFU healing rates between cohorts. There was a correlation noted between wound healing and prior minor amputations and between statin use and age, duration of DM, LDL cholesterol, total cholesterol, HTN, CAD and HLD. Additionally, we observed no correlation between DFU healing rates and use of a statin medication.

Single-cell profiling identifies a CD8bright CD244bright Natural Killer cell subset that reflects disease activity in HLA-A29-positive birdshot chorioretinopathy.

Birdshot chorioretinopathy is an inflammatory eye condition strongly associated with MHC-I allele HLA-A29. The striking association with MHC-I suggests involvement of T cells, whereas natural killer (NK) cell involvement remains largely unstudied. Here we show that HLA-A29-positive birdshot chorioretinopathy patients have a skewed NK cell pool containing expanded CD16 positive NK cells which produce more proinflammatory cytokines. These NK cells contain populations that express CD8A which is involved in MHC-I recognition on target cells, display gene signatures indicative of high cytotoxic activity (GZMB, PRF1 and ISG15), and signaling through NK cell receptor CD244 (SH2D1B). Long-term monitoring of a cohort of birdshot chorioretinopathy patients with active disease identifies a population of CD8bright CD244bright NK cells, which rapidly declines to normal levels upon clinical remission following successful treatment. Collectively, these studies implicate CD8bright CD244bright NK cells in birdshot chorioretinopathy.

Females have lower salivary flow than males, before and after radiation therapy for head/neck cancer.

OBJECTIVE: To compare salivary flow rates between females and males, before and after radiation therapy (RT) for head and neck cancer (HNC). METHODS: Prospective observational multicenter cohort study (OraRad). Stimulated whole salivary flow was measured before RT and at 6 and 18 months after RT. RESULTS: Mean (95% confidence interval) salivary flow in g/min before RT was 0.81 (0.71, 0.90) in females (n = 107) and 1.20 (1.15, 1.25) in males (n = 391) (p < 0.001); at 6 months was 0.34 (0.24, 0.44) in females and 0.50 (0.44, 0.55) in males (p = 0.01); at 18 months was 0.49 (0.38, 0.59) in females and 0.70 (0.64, 0.75) in males (p < 0.001). Median nadir salivary flow after RT was 0.22 in females and 0.35 in males (p < 0.001). A lower nadir salivary flow in females, but not males, was associated with an increased risk for tooth failure (p = 0.02). CONCLUSIONS: Females with HNC have lower stimulated whole salivary flow than males, before and after RT. Low salivary flow after RT may be a risk factor for tooth failure among females. The lower pre-RT salivary flow rates in females, combined with prior literature in other populations, indicates that, in general, females have lower stimulated salivary flow than males.

Protease-Induced Excitation of Dorsal Root Ganglion Neurons in Response to Acute Perturbation of the Gut Microbiota Is Associated With Visceral and Somatic Hypersensitivity.

BACKGROUND & AIMS: Abdominal pain is a major symptom of diseases that are associated with microbial dysbiosis, including irritable bowel syndrome and inflammatory bowel disease. Germ-free mice are more prone to abdominal pain than conventionally housed mice, and reconstitution of the microbiota in germ-free mice reduces abdominal pain sensitivity. However, the mechanisms underlying microbial modulation of pain remain elusive. We hypothesized that disruption of the intestinal microbiota modulates the excitability of peripheral nociceptive neurons. METHODS: In vivo and in vitro assays of visceral sensation were performed on mice treated with the nonabsorbable antibiotic vancomycin (50 µg/mL in drinking water) for 7 days and water-treated control mice. Bacterial dysbiosis was verified by 16s rRNA analysis of stool microbial composition. RESULTS: Treatment of mice with vancomycin led to an increased sensitivity to colonic distension in vivo and in vitro and hyperexcitability of dorsal root ganglion (DRG) neurons in vitro, compared with controls. Interestingly, hyperexcitability of DRG neurons was not restricted to those that innervated the gut, suggesting a widespread effect of gut dysbiosis on peripheral pain circuits. Consistent with this, mice treated with vancomycin were more sensitive than control mice to thermal stimuli applied to hind paws. Incubation of DRG neurons from naive mice in serum from vancomycin-treated mice increased DRG neuron excitability, suggesting that microbial dysbiosis alters circulating mediators that influence nociception. The cysteine protease inhibitor E64 (30 nmol/L) and the protease-activated receptor 2 (PAR-2) antagonist GB-83 (10 µmol/L) each blocked the increase in DRG neuron excitability in response to serum from vancomycin-treated mice, as did the knockout of PAR-2 in NaV1.8-expressing neurons. Stool supernatant, but not colonic supernatant, from mice treated with vancomycin increased DRG neuron excitability via cysteine protease activation of PAR-2. CONCLUSIONS: Together, these data suggest that gut microbial dysbiosis alters pain sensitivity and identify cysteine proteases as a potential mediator of this effect.

Factors associated with oral hygiene compliance in patients treated with radiation therapy for head and neck cancer.

BACKGROUND: Patients who are oral hygiene noncompliant (OHNC) are more likely to lose teeth after radiation therapy (RT) for head and neck cancer (HNC), which increases the risk of developing osteoradionecrosis. A previous study revealed that patients who were OHNC at baseline (BL) who became oral hygiene compliant during follow-up had the best tooth-failure outcomes. The purpose of this study was to identify factors associated with oral hygiene compliance (OHC), overall, and among those who were BL OHNC. METHODS: This was an observational, prospective, cohort study of 518 patients with HNC assessed before RT and at post-RT follow-up visits every 6 months for 2 years. Patient and treatment-related information was collected at BL and during follow-up, including self-reported OHC. OHC was defined as toothbrushing at least twice daily and flossing at least once daily. RESULTS: Of the 296 patients who self-reported being BL OHNC, 44 (14.9%) became oral hygiene compliant at all follow-up visits. Among this group, those who had dental insurance (P = .026), surgery before RT (P = .008), limited mouth opening before RT (P = .001), compliant fluoride use (P = .023), primary RT site of oral cavity (P = .004), and primary surgical site of larynx and hypopharynx (P = .042) were more likely to become oral hygiene compliant post-RT. CONCLUSIONS: The reasons for the cohort of patients with HNC in this study being OHNC are multifaceted and relate to socioeconomic factors and cancer characteristics. PRACTICAL IMPLICATIONS: Finding ways to increase OHC and fluoride use among patients with HNC who are at greatest risk of being OHNC should be explored.

Measurement of the Association of Pain with Clinical Characteristics in Oral Cancer Patients at Diagnosis and Prior to Cancer Treatment.

Aim: Oral cancer patients suffer pain at the site of the cancer, which degrades quality of life (QoL). The University of California San Francisco Oral Cancer Pain Questionnaire (UCSFOCPQ), the only validated instrument specifically designed for measuring oral cancer pain, measures the intensity and nature of pain and the level of functional restriction due to pain. Purpose: The aim of this study was to compare pain reported by untreated oral cancer patients on the UCSFOCPQ with pain they reported on the Brief Pain Inventory (BPI), an instrument widely used to evaluate cancer and non-cancer pain. Patients and Methods: The correlation between pain measured by the two instruments and clinical characteristics were analyzed. Thirty newly diagnosed oral cancer patients completed the UCSFOCPQ and the BPI. Results: Pain severity measurements made by the UCSFOCPQ and BPI were concordant; however, the widely used BPI average pain over 24 hours score appeared less sensitive to detect association of oral cancer pain with clinical characteristics of patients prior to treatment (nodal status, depth of invasion, DOI). A BPI average score that includes responses to questions that measure both pain severity and interference with function performs similarly to the UCSFOCPQ in detection of associations with nodal status, pathologic T stage (pT stage), stage and depth of invasion (DOI). Conclusion: Pain assessment instruments that measure sensory and interference dimensions of oral cancer pain correlate with biologic features and clinical behavior.

Reduced mouth opening in patients with head and neck cancer treated with radiation therapy: an analysis of the Clinical Registry of Dental Outcomes in Head and Neck Cancer Patients (OraRad).

OBJECTIVE: Trismus/reduced mouth opening (RMO) is a common side effect of radiotherapy (RT) for head and neck cancer (HNC). The objective was to measure RMO, identify risk factors for RMO, and determine its impact on quality of life (QOL). STUDY DESIGN: OraRad is an observational, prospective, multicenter cohort study of patients receiving curative intent RT for HNC. Interincisal mouth opening measurements (n = 565) and patient-reported outcomes were recorded before RT and every 6 months for 2 years. Linear mixed-effects models were used to evaluate change in mouth opening and assess the relationship between trismus history and change in QOL measures. RESULTS: Interincisal distance decreased from a mean (SE) of 45.1 (0.42) mm at baseline to 42.2 (0.44) at 6 months, with slight recovery at 18 months (43.3, 0.46 mm) but no additional improvement by 24 months. The odds of trismus (opening <35 mm) were significantly higher at 6 months (odds ratio [OR] = 2.21, 95% CI: 1.30 to 3.76) and 12 months (OR = 1.87, 95% CI: 1.08 to 3.25) compared with baseline. Females were more likely to experience trismus at baseline and during follow-up (P < .01). Patients with oral cavity cancer had the highest risk for trismus at baseline and post-RT (P < .01). RMO was associated with higher RT dose to the primary site and receiving concomitant chemotherapy (P < .01). Trismus was associated with self-reported difficulty opening the mouth and dry mouth (P < .01). CONCLUSIONS: A decrease in mouth opening is a common treatment-related toxicity after RT, with some recovery by 18 months. Trismus has a significant impact on survivor QOL.

Residential Address Amplifies Health Disparities and Risk of Infection in Individuals With Diabetic Foot Ulcers.

OBJECTIVE: To determine the association between social determinants of health (SDOH) and a diagnosis of diabetic foot ulcer (DFU) infection. RESEARCH DESIGN AND METHODS: Targeted interrogation of electronic health record data using novel search engines to analyze individuals with a DFU infection during a 5-year period (2013-2017) was performed. We extracted geolocated neighborhood data and SDOH characteristics from the National Neighborhood Data Archive and used univariate and multiple logistic regression to evaluate associations with outcomes in the population with diabetes. RESULTS: Among 4.3 million people overall and 144,564 individuals with diabetes seen between 2013 and 2017, 8,351 developed DFU, of which cases 2,252 were complicated by a DFU infection. Sex interactions occurred, as men who experienced a DFU infection more frequently identified as having nonmarried status than their female counterparts. For the population with DFU infection, there were higher rates for other SDOH, including higher neighborhood disadvantaged index score, poverty, nonmarriage, and less access to physician/allied health professionals (all P < 0.01). In multiple logistic regression, those individuals who developed DFU infection came from neighborhoods with greater Hispanic and/or foreign-born concentrations (odds ratio 1.11, P = 0.015). CONCLUSIONS: We found significant differences in neighborhood characteristics driving a higher risk for DFU infection in comparisons with the grouping of individuals with diabetes overall, including increased risk for individuals with Hispanic and/or foreign-born immigration status. These data strongly support the need to incorporate SDOH, particularly ethnic and immigration status, into triage algorithms for DFU risk stratification to prevent severe diabetic foot complications and move beyond biologic-only determinants of health.

Neuropilin-1 is a co-receptor for NGF and TrkA-evoked pain.

Nerve growth factor (NGF) monoclonal antibodies (mAb) are one of the few patient-validated non-opioid treatments for chronic pain, despite failing to gain FDA approval due to worsened joint damage in some osteoarthritis patients. Herein, we demonstrate that neuropilin-1 (NRP1) is a nociceptor-enriched co-receptor for NGF that is necessary for tropomyosin-related kinase A (TrkA) signaling of pain. NGF binds NRP1 with nanomolar affinity. NRP1 and G Alpha Interacting Protein C-terminus 1 (GIPC1), a NRP1/TrkA adaptor, are coexpressed with TrkA in human and mouse nociceptors. NRP1 small molecule inhibitors and blocking mAb prevent NGF-stimulated action potential firing and activation of Na+ and Ca2+ channels in human and mouse nociceptors and abrogate NGF-evoked and inflammatory nociception in mice. NRP1 knockdown blunts NGF-stimulated TrkA phosphorylation, kinase signaling and transcription, whereas NRP1 overexpression enhances NGF and TrkA signaling. As well as interacting with NGF, NRP1 forms a heteromeric complex with TrkA. NRP1 thereby chaperones TrkA from the biosynthetic pathway to the plasma membrane and then to signaling endosomes, which enhances NGF-induced TrkA dimerization, endocytosis and signaling. Knockdown of GIPC1, a PDZ-binding protein that scaffolds NRP1 and TrkA to myosin VI, abrogates NGF-evoked excitation of nociceptors and pain-like behavior in mice. We identify NRP1 as a previously unrecognized co-receptor necessary for NGF/TrkA pain signaling by direct NGF binding and by chaperoning TrkA to the plasma membrane and signaling endosomes via the adaptor protein GIPC1. Antagonism of NRP1 and GIPC1 in nociceptors offers a long-awaited alternative to systemic sequestration of NGF with mAbs for the treatment of pain.

A mean-field description for the expansion kinetics of activated T cell populations.

When lymphocytes encounter their cognate antigen, they become activated and undergo a limited number of cell divisions during which they differentiate into memory or effector cells or die. While the dynamics of individual cells are often heterogeneous, the expansion kinetics at the population level are highly reproducible, suggesting a mean-field description. To generate a finite division destiny, we consider two scenarios: Cells stop dividing after a certain number of iterations or their death rate increases with each cell division. The dynamics of the combined system can be mapped to a partial differential equation, and for a suitable choice of the activation rate, we obtain simple analytical solutions for the total cell number and the mean number of divisions per cell which can well describe the signal-dependent T cell expansion kinetics from in vitro experiments. Interestingly, only the division cessation mechanism yields an expression for the division destiny that does not contradict experiments. We show that the generation-dependent decrease of the division rate in individual cells leads to a time-dependent decrease at the population level which is consistent with a "time-to-die" control mechanism for the division destiny as suggested previously. We also derive mean-field equations for the total cell number which provide a basis for implementing T cell expansion kinetics into quantitative systems pharmacology models for immuno-oncology and CAR-T cell therapies.

The Interplay of Permeability, Metabolism, Transporters, and Dosing in Determining the Dynamics of the Tissue/Plasma Partition Coefficient and Volume of Distribution-A Theoretical Investigation Using Permeability-Limited, Physiologically Based Pharmacokinetic Modeling.

A permeability-limited physiologically based pharmacokinetic (PBPK) model featuring four subcompartments (corresponding to the intracellular and extracellular water of the tissue, the residual plasma, and blood cells) for each tissue has been developed in MATLAB/SimBiology and applied to various what-if scenario simulations. This model allowed us to explore the complex interplay of passive permeability, metabolism in tissue or residual blood, active uptake or efflux transporters, and different dosing routes (intravenous (IV) or oral (PO)) in determining the dynamics of the tissue/plasma partition coefficient (Kp) and volume of distribution (Vd) within a realistic pseudo-steady state. Based on the modeling exercise, the permeability, metabolism, and transporters demonstrated significant effects on the dynamics of the Kp and Vd for IV bolus administration and PO fast absorption, but these effects were not as pronounced for IV infusion or PO slow absorption. Especially for low-permeability compounds, uptake transporters were found to increase both the Kp and Vd at the pseudo-steady state (Vdss), while efflux transporters had the opposite effect of decreasing the Kp and Vdss. For IV bolus administration and PO fast absorption, increasing tissue metabolism was predicted to elevate the Kp and Vdss, which contrasted with the traditional derivation from the steady-state perfusion-limited PBPK model. Moreover, metabolism in the residual blood had more impact on the Kp and Vdss compared to metabolism in tissue. Due to its ability to offer a more realistic description of tissue dynamics, the permeability-limited PBPK model is expected to gain broader acceptance in describing clinical PK and observed Kp and Vdss, even for certain small molecules like cyclosporine, which are currently treated as perfusion-limited in commercial PBPK platforms.

Empirical Antibiotic Therapy in Diabetic Foot Ulcer Infection Increases Hospitalization.

Background: We evaluated the outcomes associated with initial antibiotic management strategies for infected diabetic foot ulcers (DFUs) diagnosed in an outpatient multidisciplinary center. Methods: Consecutive outpatient individuals with infected DFUs, stratified according to Infectious Diseases Society of America infection severity, were followed for 1 year from the initial antibiotic administration to treat acute infection. The main outcomes were hospitalization rates for a diabetes-related foot complication within 30 days of diagnosis and requiring an amputation or death during follow-up. Outcomes were analyzed by regression analysis, accounting for demographics, clinical characteristics, and antibiotic therapy. Results: Among 147 outpatients with infected DFUs, 116 were included. Infections were categorized as mild (68%), moderate (26%), and severe (6%). Empirical antibiotics (not culture-guided) were prescribed as initial treatment in 39 individuals, while 77 received culture-based antibiotics. There were no differences in demographic or clinical characteristics between the antibiotic administration groups, except for a higher body mass index and prevalence of chronic kidney disease in the empirical cohort. Forty-two infected DFU patients required hospitalization within 30 days of diagnosis for the same reason. The relative risk for hospitalizations was 1.87 greater in those with mild infections when treated with empirical antibiotics compared with culture-directed antibiotics. There were no differences in amputations and/or death at 1 year follow-up. Conclusions: These data support obtaining tissue culture to guide antibiotic therapy, regardless of DFU infection severity, to decrease hospitalizations.

Calcitonin Related Polypeptide Alpha Mediates Oral Cancer Pain.

Oral cancer patients suffer pain at the site of the cancer. Calcitonin gene related polypeptide (CGRP), a neuropeptide expressed by a subset of primary afferent neurons, promotes oral cancer growth. CGRP also mediates trigeminal pain (migraine) and neurogenic inflammation. The contribution of CGRP to oral cancer pain is investigated in the present study. The findings demonstrate that CGRP-immunoreactive (-ir) neurons and neurites innervate orthotopic oral cancer xenograft tumors in mice. Cancer increases anterograde transport of CGRP in axons innervating the tumor, supporting neurogenic secretion as the source of CGRP in the oral cancer microenvironment. CGRP antagonism reverses oral cancer nociception in preclinical oral cancer pain models. Single-cell RNA-sequencing is used to identify cell types in the cancer microenvironment expressing the CGRP receptor components, receptor activity modifying protein 1 Ramp1 and calcitonin receptor like receptor (CLR, encoded by Calcrl). Ramp1 and Calcrl transcripts are detected in cells expressing marker genes for Schwann cells, endothelial cells, fibroblasts and immune cells. Ramp1 and Calcrl transcripts are more frequently detected in cells expressing fibroblast and immune cell markers. This work identifies CGRP as mediator of oral cancer pain and suggests the antagonism of CGRP to alleviate oral cancer pain.

Therapeutic antagonism of the neurokinin 1 receptor in endosomes provides sustained pain relief.

The hypothesis that sustained G protein-coupled receptor (GPCR) signaling from endosomes mediates pain is based on studies with endocytosis inhibitors and lipid-conjugated or nanoparticle-encapsulated antagonists targeted to endosomes. GPCR antagonists that reverse sustained endosomal signaling and nociception are needed. However, the criteria for rational design of such compounds are ill-defined. Moreover, the role of natural GPCR variants, which exhibit aberrant signaling and endosomal trafficking, in maintaining pain is unknown. Herein, substance P (SP) was found to evoke clathrin-mediated assembly of endosomal signaling complexes comprising neurokinin 1 receptor (NK1R), Gαq/i, and ßarrestin-2. Whereas the FDA-approved NK1R antagonist aprepitant induced a transient disruption of endosomal signals, analogs of netupitant designed to penetrate membranes and persist in acidic endosomes through altered lipophilicity and pKa caused sustained inhibition of endosomal signals. When injected intrathecally to target spinal NK1R+ve neurons in knockin mice expressing human NK1R, aprepitant transiently inhibited nociceptive responses to intraplantar injection of capsaicin. Conversely, netupitant analogs had more potent, efficacious, and sustained antinociceptive effects. Mice expressing C-terminally truncated human NK1R, corresponding to a natural variant with aberrant signaling and trafficking, displayed attenuated SP-evoked excitation of spinal neurons and blunted nociceptive responses to SP. Thus, sustained antagonism of the NK1R in endosomes correlates with long-lasting antinociception, and domains within the C-terminus of the NK1R are necessary for the full pronociceptive actions of SP. The results support the hypothesis that endosomal signaling of GPCRs mediates nociception and provides insight into strategies for antagonizing GPCRs in intracellular locations for the treatment of diverse diseases.

Tooth-level predictors of tooth loss and exposed bone after radiation therapy for head and neck cancer.

BACKGROUND: The objective of this study was to identify tooth-level risk factors for use during preradiation dental care management to predict risk of tooth failure (tooth lost or declared hopeless) and exposed bone after radiation therapy (RT) for head and neck cancer (HNC). METHODS: The authors conducted a prospective observational multicenter cohort study of 572 patients receiving RT for HNC. Participants were examined by calibrated examiners before RT and then every 6 months until 2 years after RT. Analyses considered time to tooth failure and chance of exposed bone at a tooth location. RESULTS: The following pre-RT characteristics predicted tooth failure within 2 years after RT: hopeless teeth not extracted pre-RT (hazard ratio [HR], 17.1; P < .0001), untreated caries (HR, 5.0; P < .0001), periodontal pocket 6 mm or greater (HR, 3.4; P = .001) or equaling 5 mm (HR, 2.2; P = .006), recession over 2 mm (HR, 2.8; P = .002), furcation score of 2 (HR, 3.3; P = .003), and any mobility (HR, 2.2; P = .008). The following pre-RT characteristics predicted occurrence of exposed bone at a tooth location: hopeless teeth not extracted before RT (risk ratio [RR], 18.7; P = .0002) and pocket depth 6 mm or greater (RR, 5.4; P = .003) or equaling 5 mm (RR, 4.7; P = .016). Participants with exposed bone at the site of a pre-RT dental extraction averaged 19.6 days between extraction and start of RT compared with 26.2 days for participants without exposed bone (P = .21). CONCLUSIONS: Individual teeth with the risk factors identified in this study should be considered for extraction before RT for HNC, with adequate healing time before start of RT. PRACTICAL IMPLICATIONS: The findings of this trial will facilitate evidence-based dental management of the care of patients receiving RT for HNC. This clinical trial was registered at Clinicaltrials.gov. The registration number is NCT02057510.

Oral health-related quality of life after radiation therapy for head and neck cancer: the OraRad study.

PURPOSE: Head and neck cancer (HNC) treatment results in morbidity impacting quality of life (QOL) in survivorship. This analysis evaluated changes in oral health-related QOL (OH-QOL) up to 2 years after curative intent radiation therapy (RT) for HNC patients and factors associated with these changes. METHODS: 572 HNC patients participated in a multicenter, prospective observational study (OraRad). Data collected included sociodemographic, tumor, and treatment variables. Ten single-item questions and 2 composite scales of swallowing problems and senses problems (taste and smell) from a standard QOL instrument were assessed before RT and at 6-month intervals after RT. RESULTS: The most persistently impacted OH-QOL variables at 24 months included: dry mouth; sticky saliva, and senses problems. These measures were most elevated at the 6-month visit. Aspects of swallowing were most impacted by oropharyngeal tumor site, chemotherapy, and non-Hispanic ethnicity. Problems with senses and dry mouth were worse with older age. Dry mouth and sticky saliva increased more among men and those with oropharyngeal cancer, nodal involvement, and use of chemotherapy. Problems with mouth opening were increased by chemotherapy and were more common among non-White and Hispanic individuals. A 1000 cGy increase in RT dose was associated with a clinically meaningful change in difficulty swallowing solid food, dry mouth, sticky saliva, sense of taste, and senses problems. CONCLUSIONS: Demographic, tumor, and treatment variables impacted OH-QOL for HNC patients up to 2 years after RT. Dry mouth is the most intense and sustained toxicity of RT that negatively impacts OH-QOL of HNC survivors. GOV IDENTIFIER: NCT02057510; first posted February 7, 2014.

Tackling diabetic foot: limb salvage during the COVID-19 pandemic.

Purpose: Lower extremity amputation resulting from diabetic foot ulcer, with neuropathic and/or ischemic etiologies, remains a devastating and costly complication of diabetes mellitus. This study evaluated changes in care delivery of diabetic foot ulcer patients during the COVID-19 pandemic. A longitudinal assessment evaluating the ratio of major lower extremity amputation to minor lower extremity amputations after implementation of novel strategies to combat access restrictions was compared to the pre-COVID-19 era. Methods: The ratio of major to minor lower extremity amputation (i.e. the high-to-low ratio) was assessed at two academic institutions, the University of Michigan, and University of Southern California, in a population of patients with diabetes who had direct access to multidisciplinary foot care clinics in the 2 years prior to the pandemic and the first 2 years of the COVID-19 pandemic. Results: Patient characteristics and volumes including patients with diabetes and those with a diabetic foot ulcer were similar between eras. In addition, inpatient diabetic foot-related admissions were similar, but were suppressed by government shelter in placed mandates and subsequent COVID-19 variants surges (e.g. delta, omicron). In the control group, the Hi-Lo ratio increased every 6 months by an average of 11.8%. Meanwhile, following STRIDE implementation during the pandemic, the Hi-Lo ratio reduced by (-)11% (p < 0.001) and doubled limb salvage efforts as compared to the baseline era. The reduction of the Hi-Lo ratio was not influenced significant by patient volumes or inpatient admissions for foot infections. Conclusion: These findings signify the importance of podiatric care in the at-risk diabetic foot population. Through strategic planning and rapid implementation of at-risk diabetic foot ulcer triage, multidisciplinary teams were able to maintain accessible care during the pandemic which resulted in a reduction of amputations. Furthermore, this manuscript highlights the value of the Hi-Lo ratio as an indicator of institutional limb salvage efforts.

Protease-activated receptors in health and disease.

Proteases are signaling molecules that specifically control cellular functions by cleaving protease-activated receptors (PARs). The four known PARs are members of the large family of G protein-coupled receptors. These transmembrane receptors control most physiological and pathological processes and are the target of a large proportion of therapeutic drugs. Signaling proteases include enzymes from the circulation; from immune, inflammatory epithelial, and cancer cells; as well as from commensal and pathogenic bacteria. Advances in our understanding of the structure and function of PARs provide insights into how diverse proteases activate these receptors to regulate physiological and pathological processes in most tissues and organ systems. The realization that proteases and PARs are key mediators of disease, coupled with advances in understanding the atomic level structure of PARs and their mechanisms of signaling in subcellular microdomains, has spurred the development of antagonists, some of which have advanced to the clinic. Herein we review the discovery, structure, and function of this receptor system, highlight the contribution of PARs to homeostatic control, and discuss the potential of PAR antagonists for the treatment of major diseases.