Targeting OXPHOS de novo purine synthesis as the nexus of FLT3 inhibitor-mediated synergistic antileukemic actions

Using a genome-wide CRISPR screen, we identified CDK9, DHODH, and PRMT5 as synthetic lethal partners with gilteritinib treatment in fms-like tyrosine kinase 3 (FLT3)-internal tandem duplication (ITD) acute myeloid leukemia (AML) and genetically and pharmacologically validated their roles in gilteritinib sensitivity. The presence of FLT3-ITD is associated with an increase in anaerobic glycolysis, rendering leukemia cells highly sensitive to inhibition of glycolysis. Supportive of this, our data show the enrichment of single guide RNAs targeting 28 glycolysis-related genes upon gilteritinib treatment, suggesting that switching from glycolysis to oxidative phosphorylation (OXPHOS) may represent a metabolic adaption of AML in gilteritinib resistance. CDK9i/FLT3i, DHODHi/FLT3i, and PRMT5i/FLT3i pairs mechanistically converge on OXPHOS and purine biosynthesis blockade, implying that targeting the metabolic functions of these three genes and/or proteins may represent attractive strategies to sensitize AML to gilteritinib treatment. Our findings provide the basis for maximizing therapeutic impact of FLT3-ITD inhibitors and a rationale for a clinical trial of these novel combinations.

A Large Cluster of New Onset Autoimmune Myositis in the Yorkshire Region Following SARS-CoV-2 Vaccination

Background: The novel SARS-CoV-2 vaccines partially exploit intrinsic DNA or RNA adjuvanticity, with dysregulation in the metabolism of both these nucleic acids independently linked to triggering experimental autoimmune diseases, including lupus and myositis. Methods: Herein, we present 15 new onset autoimmune myositis temporally associated with SARS-CoV-2 RNA or DNA-based vaccines that occurred between February 2021 and April 2022. Musculoskeletal, pulmonary, cutaneous and cardiac manifestations, laboratory and imaging data were collected. Results: In total, 15 cases of new onset myositis (11 polymyositis/necrotizing/overlap myositis; 4 dermatomyositis) were identified in the Yorkshire region of approximately 5.6 million people, between February 2021 and April 2022 (10 females/5 men; mean age was 66.1 years; range 37–83). New onset disease occurred after first vaccination (5 cases), second vaccination (7 cases) or after the third dose (3 cases), which was often a different vaccine. Of the cases, 6 had systemic complications including skin (3 cases), lung (3 cases), heart (2 cases) and 10/15 had myositis associated autoantibodies. All but 1 case had good therapy responses. Adverse event following immunization (AEFI) could not be explained based on the underlying disease/co-morbidities. Conclusion: Compared with our usual regional Rheumatology clinical experience, a surprisingly large number of new onset myositis cases presented during the period of observation. Given that antigen release inevitably follows muscle injury and given the role of nucleic acid adjuvanticity in autoimmunity and muscle disease, further longitudinal studies are required to explore potential links between novel coronavirus vaccines and myositis in comparison with more traditional vaccine methods.

Presentation, clinical course and complications in trauma patients with concomitant COVID-19 infection

BACKGROUND

This study investigated the impact of COVID-19 infection on hospitalized trauma patients.

METHODS

A retrospective review of hospitalized trauma patients at a level I trauma center was performed from March-December 2020. Data pertaining to patient demographics, presentation and hospital course was compared between COVID positive and negative trauma patients.

RESULTS

There were 4,912 patients and 179 (3.64%) were COVID-19 positive. Demographics and clinical presentation did not differ significantly between those with and without concomitant COVID-19. However, COVID positive trauma patients had higher rates of acute kidney injury (p = 0.016), sepsis (p = 0.016), unplanned intubation (p = 0.002) and unplanned return to the ICU (p = 0.01). The COVID positive cohort also had longer hospital stays (p < 0.01) with no significant difference in mortality.

CONCLUSIONS

In the setting of an ongoing pandemic, awareness of the complications COVID positive trauma patients are predisposed to is important for providers.

Excess Deaths during COVID-19 pandemic in Alberta, Canada

Purpose

To determine if there was excess mortality in Alberta, Canada during the pandemic. We sought to confirm if excess mortality affected all age groups equally and determine what proportion of excess deaths is directly related to COVID-19.

Methods & Materials

Excess mortality was calculated by comparing observed to expected number of deaths. Monthly Crude death rates (CDR) for 2015 to 2019 was calculated by dividing monthly deaths by the mid-year population. Expected deaths was calculated by multiplying mean monthly CDR by the mid-year population in 2020 and the projected mid-year population in 2021 to calculate expected deaths. Age-adjusted monthly mortality rates for January 2020 to March 2021 was compared to the previous 5 years.

Results

From January 2020 to May 2021 there was a 11% excess mortality corresponding to an average of 248 monthly excess deaths with a minimum of 49 deaths in January 2020 (no COVID-19-related deaths) and a maximum of 781 excess deaths in December 2020. COVID-19 related deaths (n=2266) account for 53.8 % of the total excess deaths (n=4214) that occurred in the 17 months.

Increase in all cause -excess deaths was proportionately higher, and in significantly greater numbers, in the younger age groups. Deaths directly linked to COVID-19 were: 8 (20-29 years), 12 (30-39 years), 32 (40-49 years), 74 (50-59 years), 225 (60-69 years), 409 (70-79 years), and 1274 (>80 years)

Statistically significant increases in monthly drug poisoning deaths from March 2020 to April 2021 with a total of 1819 deaths. Excess 731 drug poisoning deaths representing 18.2 % of total all-cause excess mortality affected mostly those age 25-60. 53.9 % of all excess deaths is directly related to COVID-19 and 18.2% are drug poisoning related excess deaths. The remaining 27.9 % of excess deaths are likely due other factors such as limited access to urgent medical care.

Conclusion

There was statistically significant increase in all-cause mortality. Although older adults are more likely to die of COVID-19, there was massive increase in non-COVID-19 related mortality among the youth. These should be factored in public policy decisions on epidemic/pandemic management.

Initial evaluation of 2D and 3D simulated high-speed 1000 fps vascular contrast-flow image sequences using computational fluid dynamics (CFD)

Digital subtraction angiography (DSA) remains the clinical standard for detailed visualization of the neurovasculature due to its high-spatial resolution; however, detailed blood-flow quantification is impaired by its low-temporal resolution. Advances in photon-counting detector technology have led us to develop High-Speed Angiography (HSA), where x-ray images are acquired at 1000 fps for more accurate visualization and quantification of blood flow. We have implemented a physics-based optical flow method to extract such information from HSA, but validation of the angiography-derived velocity distributions is not straightforward. Computational fluid dynamics (CFD) is widely regarded as the benchmark for hemodynamic analysis, as it provides a multitude of quantitative flow parameters throughout the volume of interest. However, there are several limitations with this method related to over-simplification of boundary conditions and suboptimal meshing (spatial resolution), that make CFD simulation results an inexact criterion for validation. To overcome this issue for HSA validation, CFD was used to generate both simulated high-speed angiograms and the corresponding ground-truth 3D flow fields to better understand the relationship between the 3D volumetric-flow distribution and the 2D projected-flow distribution as is obtained with angiography, and the subsequent 2D approximation of flow velocity. Several geometries were investigated, ranging from simple pipe models to complex patient-specific aneurysms. Simulated datasets were analyzed with the optical flow algorithm, and the effects of flow divergence, quantum mottle, and intensity gradient on the calculation were evaluated. From these simulations, we can evaluate whether flow fields reconstructed from HSA are representative of significant flow patterns in the 3D vasculature.

Real-time Detection of Patient Head Position and Cephalometric Landmarks from Neuro-Interventional Procedure Images Using Machine Learning for Patient Eye-Lens Dose Prediction

A deep learning (DL) model has been developed to estimate patient-lens dose in real-time for given exposure and geometric conditions during fluoroscopically-guided neuro-interventional procedures. Parameters input into the DL model for dose prediction include the patient head shift from isocenter and cephalometric landmark locations as a surrogate for head size. Machine learning (ML) models were investigated to automatically detect these parameters from the in-procedure fluoroscopic image. Fluoroscopic images of a Kyoto Kagaku anthropomorphic head phantom were taken at various known X (transverse) and Y (longitudinal) shifts, as well as different magnification modes, to create an image database. For each image, anatomical landmark coordinate locations were obtained manually using ImageJ and are used as ground-truth labels for training. This database was then used to train the two separate ML models. One ML model predicts the patient head shift in both the X and Y directions and the other model predicts the coordinates of the anatomical landmarks. From the coordinates, the distance between these anatomical landmarks is calculated, and input into the DL dose-prediction model. Model performance was evaluated using mean absolute error (MAE) and mean absolute percentage error (MAPE) for the head-shift and landmark-coordinate models, respectively. The goal is to implement these two separate models into the Dose Tracking System (DTS) developed by our group. This would allow the DTS to automatically detect the patient head size and position for eye-lens dose prediction and eliminate the need for manual input by the clinical staff.

Peritonsillar Abscess at a Dedicated Otolaryngology Emergency Department

Aim Peritonsillar abscess (PTA) is the most common suppurative complication of acute tonsillitis. It requires urgent specialist treatment due to the risk of progression to airway compromise. We aimed to review referral pathways to a dedicated otolaryngology emergency department (ORL-ED), identify causative organisms and discuss COVID-19 implications. Methods A retrospective review of patients presenting to the ORL-ED between January 2018 and December 2019 was undertaken. Data extracted included demographics, referral source, treatment, microbiology results and length of stay. Statistical analysis of seasonal variation of presentation and causative organisms employed Chi-Square and Fisher's Exact Test, respectively. Results There were 53 PTA presentations. 51 were admitted accounting for 44.3% (51/115) of ED admissions. The median patient age was 31 years (IQR 20-40yrs). GP referral accounted for 48/53 (90.6%). There was no statistically significant seasonality (χ2=5.94, p=0.11) in presentation. Microbiology samples were available for 44 patients. Streptococcus was identified in 19/44 (43.2%) patients. 85% (45/53) of patients received Co-amoxiclav. Discussion PTA is a perennial condition with diverse causative organisms. Antibiotic choice should reflect this. The majority of patients are referred from primary care, emphasising the role of the GP in initial diagnosis and the importance of clinical education in this regard.

Reduced SOD2 expression does not influence prion disease course or pathology in mice

Prion diseases are progressive, neurodegenerative diseases affecting humans and animals. Also known as the transmissible spongiform encephalopathies, for the hallmark spongiform change seen in the brain, these diseases manifest increased oxidative damage early in disease and changes in antioxidant enzymes in terminal brain tissue. Superoxide dismutase 2 (SOD2) is an antioxidant enzyme that is critical for life. SOD2 knock-out mice can only be kept alive for several weeks post-birth and only with antioxidant therapy. However, this results in the development of a spongiform encephalopathy. Consequently, we hypothesized that reduced levels of SOD2 may accelerate prion disease progression and play a critical role in the formation of spongiform change. Using SOD2 heterozygous knock-out and litter mate wild-type controls, we examined neuronal long-term potentiation, disease duration, pathology, and degree of spongiform change in mice infected with three strains of mouse adapted scrapie. No influence of the reduced SOD2 expression was observed in any parameter measured for any strain. We conclude that changes relating to SOD2 during prion disease are most likely secondary to the disease processes causing toxicity and do not influence the development of spongiform pathology.

Understanding and breaking the intergenerational cycle of abuse in families enrolled in routine mental health services: study protocol for a randomized controlled trial and two non-interventional trials investigating mechanisms of change within the UBICA II consortium

Background

Parents’ mental illness (MI) and parental history of early life maltreatment (ELM) are known to be significant risk factors for poor parenting while poor parenting is a crucial mediator of the intergenerational continuity of child maltreatment. Hence, maltreatment prevention programs for families with an MI parent, which pay particular attention to experiences of ELM in the parent, are urgently needed. Parental mentalizing was previously found to mediate successful parenting. Interventions aimed at improving the parental mentalizing capacity reduced maltreatment risk in parents. The aim of the present study is to investigate the effectiveness of a mentalization-based parenting-counseling in acutely mentally ill parents currently treated at a psychiatric hospital.

Methods

Mentalization-based parenting-counseling (MB-PC) vs. enhanced standard clinical care (SCC+) will be administered in a cluster-randomized-controlled trial (RCT). Patients treated at psychiatric hospitals with children between 1.5 and 15 years will be included in the trial. MB-PC will be administered as a 12-h combined individual and group program enriched by social counseling (over a course of 5 weeks) as add-on to standard clinical care, while the control condition will be standard clinical care plus a 90-min psychoeducation workshop on positive parenting. Primary efficacy endpoint is self-reported parenting practices at follow-up. Embedded within the RCT will be two sub-studies investigating social cognition and dyadic synchrony as biobehavioral mechanisms of change.

Discussion

The main goal of the present study is to investigate ways to break the intergenerational continuity of maltreatment by assessing the benefits of a prevention program which aims at improving parenting in vulnerable mothers and fathers. MB-PC is a short, low-cost intervention which can be delivered by nurses and social workers and is applicable to MI patients with children with a broad range of diagnoses. If it is shown to be effective, it can be directly implemented into standard psychiatric hospital care thereby providing help to prevent child maltreatment.

Trial registration

German Clinical Trials Register DRKS00017398. Registered on 5 July 2019

Feasibility and Acceptability of a Patient Navigation Intervention to Prevent Suicide in LGBTQ Youth and Young Adults

Background

Across Western countries, young LGBTQ+ individuals are at a four to seven-fold increased risk of attempting suicide, compared to the general public. Despite these substantial health disparities, no known empirically supported suicide prevention programs exist for this highly vulnerable population. Patient navigation (PN), as an intervention to assist people in overcoming barriers to care, paired with the Safety Planning Intervention (SPI), may be a promising intervention to target mechanisms (e.g., thwarted belongingness and suicide-related coping skills) that theoretically underlie suicide. The purpose of this presentation is to describe the developed intervention and present initial data on its feasibility and acceptability.

Methods

In collaboration with a Participatory Planning Group (PPG), an iterative process was used to develop a PN+SPI intervention to prevent suicide among at-risk LGBTQ+ youth and young adults. A mixed-methods case series was used to examine feasibility and acceptability of implementing the PN+SPI intervention over a three-month period of time.

Results

Theoretical models regarding suicidality and LGBTQ+ mental health along with PPG feedback have informed the development of the PN+SPI intervention, with 7 modules included in feasibility evaluation: 1) Introduction + SPI; 2) Minority Stress Psychoeducation; 3) Barriers to Mental Health Services; 4) Barriers to Community Resources; 5) Decision Making; 6) Crisis Intervention; and 7) Wrap Up.

Conclusions

This project has the potential for reducing mortality and morbidity due to suicide attempts among LGBTQ+ youth/emerging adults, who are one of the most vulnerable groups for attempting suicide globally. Given the brevity of the PN+SPI intervention and its emphasis on safety planning and accessing community resources, the PN+SPI intervention has high potential for wide dissemination and public health impact, should it demonstrate feasibility, acceptability, and preliminary efficacy.

Marketing mortality? Healthy vs. unhealthy food in television advertising

Background

Cardiovascular disease has been the leading killer of Americans since the Spanish flu pandemic of 1918, despite recent COVID-19 mortality. During this global pandemic, the social distancing and stay-at-home requests, there was increased television (TV) engagement, and media marketing has become more impactful in modifying consumer behaviors.

Purpose

We evaluated the healthfulness of food marketing in the United States (US), based on TV commercials most frequently aired on American primetime networks during the COVID-19 pandemic.

Methods

We reviewed a total of 104 TV commercials between 2020–2021 on network and cable programs dividing them into 4 categories: 1) fast-food chains, 2) brand-recognized individual items, 3) grocery chains, and 4) home-delivery meals. The food items displayed in each commercial were recorded and scored based on the previously validated healthful versus unhealthful nutrition scoring system (Sajita, et al., JACC 2017), assigning either positive or negative values for each food item in the commercial.

Results

We found that 58% of the commercials advertised food from fast-food chains (mean score = −2.82, indicating an average of nearly 3 more unhealthy items than healthy items per commercial), 27% were brand-recognized individual items (−0.86), 9% were grocery chains (−0.90), and 6% were for home-delivery meals (−0.33), with significant differences noted between fast-food and individual items, home deliveries and grocery chains (each p&lt;0.0001).

Conclusions

This study demonstrated that commercial TV in the US routinely promotes the consumption of foods that are known in published medical literature to be unhealthy, particularly those underpinning cardiovascular disease and its risk factors. In order to prevent an increase in cardiovascular mortality during and after this global pandemic, we suggest regulation and or legislation to curtail the frequency and/or content of these commercials, and consider a ban on such advertising to children, similar to that previously employed in Canada and the European Union.

Funding Acknowledgement

Type of funding sources: None.

Innate immune responses after stimulation with Toll-like receptor agonists in ex vivo microglial cultures and an in vivo model using mice with reduced microglia

Background

Past experiments studying innate immunity in the central nervous system (CNS) utilized microglia obtained from neonatal mouse brain, which differ developmentally from adult microglia. These differences might impact our current understanding of the role of microglia in CNS development, function, and disease.

Methods

Cytokine protein secretion was compared in ex vivo P3 and adult microglial cultures after exposure to agonists for three different toll-like receptors (TLR4, lipopolysaccharide [LPS]; TLR7, imiquimod [IMQ]; and TLR9, CpG Oligodeoxynucleotide [CpG-ODN] 1585). In addition, changes in inflammatory gene expression in ex vivo adult microglia in response to the TLR agonists was assessed. Furthermore, in vivo experiments evaluated changes in gene expression associated with inflammation and TLR signaling in brains of mice with or without treatment with PLX5622 to reduce microglia.

Results

Ex vivo adult and P3 microglia increased cytokine secretion when exposed to TLR4 agonist LPS and to TLR7 agonist IMQ. However, adult microglia decreased expression of numerous genes after exposure to TLR 9 agonist CpG-ODN 1585. In contrast, in vivo studies indicated a core group of inflammatory and TLR signaling genes increased when each of the TLR agonists was introduced into the CNS. Reducing microglia in the brain led to decreased expression of various inflammatory and TLR signaling genes. Mice with reduced microglia showed extreme impairment in upregulation of genes after exposure to TLR7 agonist IMQ.

Conclusions

Cultured adult microglia were more reactive than P3 microglia to LPS or IMQ exposure. In vivo results indicated microglial influences on neuroinflammation were agonist specific, with responses to TLR7 agonist IMQ more dysregulated in mice with reduced microglia. Thus, TLR7-mediated innate immune responses in the CNS appeared more dependent on the presence of microglia. Furthermore, partial responses to TLR4 and TLR9 agonists in mice with reduced microglia suggested other cell types in the CNS can compensate for their absence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02240-w.

Inhibition of nicotinamide phosphoribosyltransferase, the rate-limiting enzyme of the nicotinamide adenine dinucleotide salvage pathway, to target glioma heterogeneity through mitochondrial oxidative stress

BACKGROUND

Tumor-specific metabolic processes essential for cell survival are promising targets to potentially circumvent intratumoral heterogeneity, a major resistance factor in gliomas. Tumor cells preferentially using nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the salvage pathway for synthesis of NAD, a critical cofactor for diverse biological processes including cellular redox reactions, energy metabolism and biosynthesis. NAMPT is overexpressed in most malignancies, including gliomas, and can serve as a tumor-specific target.

METHODS

Effects of pharmacological inhibition of NAMPT on cellular oxygen consumption rate, extracellular acidification, mitochondrial respiration, cell proliferation, invasion and survival were assessed through in vitro and ex vivo studies on genetically heterogeneous glioma cell lines, glioma stem-like cells (GSCs) and mouse and human ex vivo organotypic glioma slice culture models.

RESULTS

Pharmacological inhibition of the NAD salvage biosynthesis pathway using a highly specific inhibitor, KPT-9274, resulted in reduction of NAD levels and related downstream metabolites, inhibited proliferation, and induced apoptosis in vitro in cell lines and ex vivo in human glioma tissue. These effects were mediated by mitochondrial dysfunction, DNA damage and increased oxidative stress leading to apoptosis in GSCs independent of genotype, IDH status or MGMT promoter methylation status. Conversely, NAMPT inhibition had minimal in vitro effects on normal human astrocytes (NHA) and no apparent in vivo toxicity in non-tumor-bearing mice.

CONCLUSIONS

Pharmacological NAMPT inhibition by KPT9274 potently targeted genetically heterogeneous gliomas by activating mitochondrial dysfunction. Our preclinical results provide a rationale for targeting the NAMPT-dependent alternative NAD biosynthesis pathway as a novel clinical strategy against gliomas.

Abstract 2260: Evaluating a rare t(X;14)(q28;q32) translocation reveals MTCP1 as a driving factor in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most prevalent adult leukemia in Western countries and is spelled by substantial genetic and clinical heterogeneity. During CLL transformation, loss or gain of genetic material appears to be a key determinant of disease phenotype and clinical outcome, with major chromosome aberrations observed in up to 80% of patients. Alternatively, balanced translocations, specifically those resulting in constitutive over-expression of various proto-oncogenes under the immunoglobulin heavy chain locus (IGH; 14q32), occur far less frequently. Despite their infrequence, molecular profiling of these rare rearrangements have revealed broad importance of un-recognized genes critical to the pathogenesis of CLL. Employing this strategy, we identified a young CLL patient with a previously undescribed t(X;14)(q28;q32) translocation, co-localization of the mature T cell proliferation 1 (MTCP1; Xq28) coding region with the IGH locus, triggering overexpression of MTCP1 in the CLL cells. Translocations involving MTCP1 are a driving factor in T-prolymphocytic leukemia; however, a role for MTCP1 in CLL has not been described. Inspired by this observation, we screened &gt;1700 suspected CLL cases and evaluated gene expression data for further evidence of MCTP1 aberrations. This query identified seven additional Xq28 rearrangements, revealed MTCP1 mRNA was globally over-expressed in CLL cells compared to normal B-cells, and increased MTCP1 mRNA expression portends a poor response to chemoimmunotherapy. To establish a role for MTCP1 as an oncogene in B cell malignancies, we generated a mouse model with B cell-specific MTCP1 overexpression (Eµ-MTCP1). Longitudinal evaluation revealed a majority of Eµ-MTCP1 mice developed a lethal hematologic malignancy between 5-12 months of age, highlighted by the progressive emergence of clonally related CLL-like B lymphocytes (CD19+/CD5+ B cells) in the blood and accumulating in the spleen and lymph nodes. To support the use of the newly generated Eµ-MTCP1 mouse as a tool for pre-clinical evaluation of CLL therapeutics, we demonstrate that continuous ibrutinib administration in Eµ-MTCP1 mice was sufficient to delay the onset of the CLL-like disease and significantly prolonged survival. In summary, we report Xq28 translocations as rare genetic abnormalities in CLL, yet being one mechanism by which CLL cells amplify expression of MTCP1 compared to normal B cell subsets. Further, the Eµ-MTCP1 mouse model should be considered as an alternative tool for both biologic assessment of co-expressed genes and pre-clinical evaluation of novel CLL therapeutics. Lastly, relevant to all cancer types, successful application of a strategy pursuing the functional consequence of genes involved in rare translocations contributed to the understanding of this disease and identified a novel target for future therapeutic consideration.

Citation Format: Janek S. Walker, Zachary A. Hing, Steven Sher, James Cronin, Katie Williams, Bonnie Harrington, Jordan N. Skinner, Casey B. Cempre, Charles T. Gregory, Max Yano, Larry P. Beaver, Brandi R. Walker, Jadwiga M. Labanowska, Nyla A. Heerema, Krzysztof Mrozek, Jennifer A. Woyach, Amy S. Ruppert, Amy Lehman, Hatice Gulcin Ozer, Vincenzo Coppola, John C. Byrd, James S. Blachly, Rosa Lapalombella. Evaluating a rare t(X;14)(q28;q32) translocation reveals MTCP1 as a driving factor in chronic lymphocytic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2260.

A study on the use of thermal imaging as a diagnostic tool for the detection of digital dermatitis in dairy cattle

Our aims were to (1) determine how interdigital skin temperature (IST), measured using infrared thermography, was associated with different stages of digital dermatitis (DD) lesions and (2) develop and validate models that can use IST measurements to identify cows with an active DD lesion. Between March 2019 and March 2020, infrared thermographic images of hind feet were taken from 2,334 Holstein cows across 4 farms. We recorded the maximum temperature reading from infrared thermographic images of the interdigital skin between the heel bulbs on the hind feet. Pregnant animals were enrolled approximately 1 to 2 mo precalving, reassessed 1 wk after calving, and again at approximately 50 to 100 d postpartum. At these time points, IST and the clinical stage of DD (M-stage scoring system: M1-M4.1) were recorded in addition to other data such as the ambient environmental temperature, height, body condition score, parity, and the presence of other foot lesions. A mixed effect linear regression model with IST as the dependent variable was fitted. Interdigital skin temperature was associated with DD lesions; compared to healthy feet, IST was highest in feet with M2 lesions, followed by M1 and M4.1 lesions. Subsequently, the capacity of IST measurements to detect the presence or absence of an active DD lesion (M1, M2, or M4.1) was explored by fitting logistic regression models, which were tested using 10-fold validation. A mixed effect logistic regression model with the presence of active DD as the dependent variable was fitted first. The average area under the curve for this model was 0.80 when its ability to detect presence of active DD was tested on 10% of the data that were not used for the model's training; an average sensitivity of 0.77 and an average specificity of 0.67 was achieved. This model was then restricted so that only explanatory variables that could be practically recorded in a nonresearch, external setting were included. Validation of this model demonstrated an average area under the curve of 0.78, a sensitivity of 0.88, and a specificity of 0.66 for 1 of the time points (precalving). Lower sensitivity and specificity were achieved for the other 2 time points. Our study adds further evidence to the relationship between DD and foot skin temperature using a large data set with multiple measurements per animal. Additionally, we highlight the potential for infrared thermography to be used for routine on-farm diagnosis of active DD lesions.