Development of a Core Outcome Set for Studies Assessing Interventions for Diabetes-Related Foot Ulceration.

OBJECTIVE: Diabetes affects 537 million people globally, with 34% expected to develop foot ulceration in their lifetime. Diabetes-related foot ulceration causes strain on health care systems worldwide, necessitating provision of high-quality evidence to guide their management. Given heterogeneity of reported outcomes, a core outcome set (COS) was developed to standardize outcome measures in studies assessing treatments for diabetes-related foot ulceration. RESEARCH DESIGN AND METHODS: The COS was developed using Core Outcome Measures in Effectiveness Trials (COMET) methodology. A systematic review and patient interviews generated a long list of outcomes that were rated by patients and experts using a nine-point Likert scale (from 1 [not important] to 9 [critical]) in the first round of the Delphi survey. Based on predefined criteria, outcomes without consensus were reprioritized in a second Delphi round. Critical outcomes and those without consensus after two Delphi rounds were discussed in the consensus meeting where the COS was ratified. RESULTS: The systematic review and patient interviews generated 103 candidate outcomes. The two consecutive Delphi rounds were completed by 336 and 176 respondents, resulting in an overall second round response rate of 52%. Of 37 outcomes discussed in the consensus meeting (22 critical and 15 without consensus after the second round), 8 formed the COS: wound healing, time to healing, new/recurrent ulceration, infection, major amputation, minor amputation, health-related quality of life, and mortality. CONCLUSIONS: The proposed COS for studies assessing treatments for diabetes-related foot ulceration was developed using COMET methodology. Its adoption by the research community will facilitate assessment of comparative effectiveness of current and evolving interventions.

Real-world outcomes following biochemical recurrence after definitive therapy with a short prostate-specific antigen doubling time: potential role of early secondary treatment.

BACKGROUND: The natural history of biochemical recurrence (BCR) managed with delayed hormonal therapy is well documented by data from Johns Hopkins. However, as many patients receive treatment prior to metastasis, we evaluated the natural history and role of prostate-specific antigen doubling time (PSADT) in a more contemporary cohort of BCR patients with nonmetastatic castration-sensitive prostate cancer (nmCSPC). METHODS: Patients in the Veterans Health Administration (VHA; 01/01/06 to 06/22/20) with nmCSPC and BCR were divided into rapid ( ≤9 months) and less rapid ( >9 to ≤15 months) PSADT cohorts. Patients with PSADT >15 months were excluded as outcomes, even with delayed treatment, are excellent. Outcomes included time to first antineoplastic therapy after BCR, metastasis, metastasis-free survival (MFS), and overall survival (OS). Cox models adjusted for baseline demographics and clinical characteristics. RESULTS: Overall, 781 patients with BCR were identified (502 rapid; 279 less rapid PSADT). Rapid PSADT was associated with shorter time to first systemic antineoplastic therapy (median 11.4 vs. 28.3 months, adjusted hazard ratio [95% confidence interval] 2.17 [1.83-2.57]), metastasis (102.4 months vs. not reached, 1.79 [1.33-2.40]), MFS (76.1 vs. 106.3 months, 1.73 [1.33-2.24]), and OS (120.5 vs. 140.5 months, 1.76 [1.22-2.54]) versus less rapid PSADT. CONCLUSION: Most patients with rapid PSADT underwent secondary treatment within 1 year after BCR. More contemporary patients treated with early secondary treatment had better outcomes than historical data from patients who had delayed treatment. Whether these results reflect the benefits of early secondary treatment or overall improvements in prostate cancer outcomes over time requires further study.

Unmet Needs and Factors Impacting Home- and Community-Based Service Use Among Rural Appalachian Caregivers of People With Alzheimer's and Dementia.

Family caregivers of persons with Alzheimer's disease and related dementias (ADRD) living in rural areas face significant health and healthcare challenges. Limited research, however, has explored factors shaping their use of home- and community-based services (HCBS). This study identifies unmet needs among caregivers of people with ADRD in rural Western North Carolina and highlights contextual factors that facilitate HCBS use. Nineteen qualitative interviews were conducted with 21 family caregivers and 1 person with ADRD between 2021 and 2022. Thematic analyses revealed unmet needs among caregivers for information, service navigation, and caregiving support. HCBS use was shaped by multiple factors including illness needs, cultural beliefs, preferences for home-based care, and place-based resources. These findings suggest that culturally tailored HCBS are needed to support people with ADRD and their caregivers in rural Appalachian communities, especially those which facilitate access to paid caregiving, clearly communicate program eligibility requirements, and emphasize service availability.

Non-surgical interventions for preventing contralateral tissue loss and amputation in dysvascular patients with a primary major lower limb amputation.

RATIONALE: Major lower limb amputation (LLA, above the ankle) is performed for people with intractable pain, life-threatening infections, or non-functional limbs. Of 7500 LLAs carried out in England between 2015 and 2018, the majority of these were performed in dysvascular patients. Dysvascularity is the absence of adequate blood supply to maintain a limb's usual function (ischaemia, usually caused by peripheral arterial disease or diabetes mellitus), ultimately leading to pain and tissue injury (ulcers, gangrene, sometimes referred to as tissue loss). Among those who undergo dysvascular LLA, 5.7% and 11.5% will likely undergo contralateral LLA at one and five years respectively, which is associated with greater disability and lower likelihood of returning to work, increasing the psychological burden to the patient and socioeconomic cost to the patient and health service. While extensive research has been carried out in the management of peripheral arterial disease and the care of diabetic feet, there are no guidelines for practice on prevention of contralateral amputation. OBJECTIVES: To assess the effects of non-surgical interventions versus placebo, no intervention, or other non-surgical interventions on contralateral limb (CLL) tissue loss and amputation in dysvascular patients with a primary major LLA. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and PEDro databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers until 20 March 2023. We also checked the references of identified studies and contacted study authors and manufacturers of relevant products. ELIGIBILITY CRITERIA: We aimed to include all randomised controlled trials (RCTs) and quasi-RCTs (e.g. randomised by birthdate) comparing the effectiveness of a non-surgical intervention with placebo, no intervention, or other non-surgical intervention, in adults with a primary major LLA due to dysvascularity. Interventions could be physical, pharmacological, educational, behavioural, or organisational, and delivered by a healthcare professional or carer. OUTCOMES: Our critical and important outcomes of interest were as follows. Critical outcomes • Incidence of new localised tissue injury or ulceration (tissue loss) of the CLL, regardless of stage or classification at given time points. • Time to the development of any localised tissue injury or ulceration (tissue loss) of the CLL, regardless of stage or classification. • Incidence of new minor amputation (through the ankle, foot, or toe(s)) of the CLL at given time points. • Time to new minor amputation (through the ankle, foot, or toe(s)) of the CLL. • Incidence of new major amputation (whole limb or partial limb, above the ankle) of the CLL at given time points. • Time to new major amputation (whole limb or partial limb, above the ankle) of the CLL. Important outcomes • Survival (time to death from all causes) at 12 months. • Patient-reported outcome measures of health-related quality of life (HRQoL) using validated scales such as the 12-item Short Form Health Survey (SF-12) and EQ-5D. • Adverse events (e.g. infections in the CLL). • Hospital readmission. RISK OF BIAS: We used Cochrane's RoB 1 tool to assess risk of bias in the included study. SYNTHESIS METHODS: We were only able to perform a narrative review due to lack of data. We reported risk ratios (RR) with 95% CIs for dichotomous outcomes. We used GRADE to assess the certainty of evidence for each outcome. INCLUDED STUDIES: We found one eligible study, which compared electrostimulation of the gastrocnemius muscle and standard rehabilitation against standard rehabilitation in 50 dysvascular amputees. SYNTHESIS OF RESULTS: There was no new incidence of tissue loss reported. The following outcomes were not reported: time to new tissue loss; time to and incidence of minor amputation; HRQoL outcomes; adverse events; and hospital readmissions. Electrostimulation was associated with a three-fold reduction in the incidence of new major amputation of the CLL (RR 0.33, 95% CI 0.04 to 2.99), although time to new major amputation was not reported. There was no difference between groups in 12-month survival (RR 1.0, 95% CI 0.85 to 1.18). We judged the overall certainty of the evidence (GRADE) as very low across all outcomes, with unclear risk of selection and detection bias and high risk of performance bias. AUTHORS' CONCLUSIONS: Despite the care of the CLL being identified as a key research priority by two separate consensus papers, there is insufficient high-quality evidence to address this priority to date. We found only a single RCT suitable for inclusion, and this study was subject to risk of bias. Contralateral limb outcomes should be recorded in future research on dysvascular amputees. Until better evidence and clearer recommendations are available, this topic is likely to remain a research priority. FUNDING: This Cochrane review had no dedicated funding. REGISTRATION: Protocol available via DOI 10.1002/14651858.CD013857.

Impaired fatty acid import or catabolism in macrophages restricts intracellular growth of Mycobacterium tuberculosis.

Mycobacterium tuberculosis (Mtb) infection of macrophages reprograms cellular metabolism to promote lipid retenZon. While it is clearly known that intracellular Mtb utilize host derived lipids to maintain infection, the role of macrophage lipid processing on the bacteria's ability to access the intracellular lipid pool remains undefined. We utilized a CRISPR-Cas9 genetic approach to assess the impact of sequential steps in fatty acid metabolism on the growth of intracellular Mtb. Our analyzes demonstrate that macrophages which cannot either import, store or catabolize fatty acids restrict Mtb growth by both common and divergent anti-microbial mechanisms, including increased glycolysis, increased oxidative stress, production of pro-inflammatory cytokines, enhanced autophagy and nutrient limitation. We also show that impaired macrophage lipid droplet biogenesis is restrictive to Mtb replication, but increased induction of the same fails to rescue Mtb growth. Our work expands our understanding of how host fatty acid homeostasis impacts Mtb growth in the macrophage.

Multiple sclerosis in LRRK2 G2019S Parkinson's disease and isolated nigral degeneration in a homozygous variant carrier.

Background: LRRK2 variants have been associated with immune dysregulation as well as immune-related disorders such as IBD. A possible relationship between multiple sclerosis (MS) and LRRK2 PD has also been suggested. Further, neuropathologic studies of homozygous LRRK2 G2019S carriers with Parkinson's disease (PD) are rare, and there are no systematic reports of clinical features in those cases. Methods: We investigated the co-occurrence of PD and MS in our research cohort and report on two cases of MS in LRRK2 PD as well as neuropathological findings for one. Results: MS preceded PD in 1.4% (2/138) of participants with LRRK2 G2019S variants, and in none (0/638) with idiopathic PD (p = 0.03). One case with MS and PD was a LRRK2 G2019S homozygous carrier, and neuropathology showed evidence of substantia nigra pars compacta degeneration and pallor without Lewy deposition, as well as multiple white matter lesions consistent with MS-related demyelination. Discussion: The increased prevalence of MS in LRRK2 PD further supports an important role for immune function for LRRK2 PD. This co-occurrence, while rare, suggests that MS may be an expression of the LRRK2 G2019S variant that includes both MS and PD, with MS predating features diagnostic of PD. The neuropathology suggests that the MS-related effects occurred independent of synuclein deposition. Importantly, and in addition, the neuropathological results not only support the MS diagnosis, but provide further evidence that Lewy body pathology may be absent even in homozygote LRRK2 carriers.

Capturing RAS oligomerization on a membrane.

RAS GTPases associate with the biological membrane where they function as molecular switches to regulate cell growth. Recent studies indicate that RAS proteins oligomerize on membranes, and disrupting these assemblies represents an alternative therapeutic strategy. However, conflicting reports on RAS assemblies, ranging in size from dimers to nanoclusters, have brought to the fore key questions regarding the stoichiometry and parameters that influence oligomerization. Here, we probe three isoforms of RAS [Kirsten Rat Sarcoma viral oncogene (KRAS), Harvey Rat Sarcoma viral oncogene (HRAS), and Neuroblastoma oncogene (NRAS)] directly from membranes using mass spectrometry. We show that KRAS on membranes in the inactive state (GDP-bound) is monomeric but forms dimers in the active state (GTP-bound). We demonstrate that the small molecule BI2852 can induce dimerization of KRAS, whereas the binding of effector proteins disrupts dimerization. We also show that RAS dimerization is dependent on lipid composition and reveal that oligomerization of NRAS is regulated by palmitoylation. By monitoring the intrinsic GTPase activity of RAS, we capture the emergence of a dimer containing either mixed nucleotides or GDP on membranes. We find that the interaction of RAS with the catalytic domain of Son of Sevenless (SOScat) is influenced by membrane composition. We also capture the activation and monomer to dimer conversion of KRAS by SOScat. These results not only reveal the stoichiometry of RAS assemblies on membranes but also uncover the impact of critical factors on oligomerization, encompassing regulation by nucleotides, lipids, and palmitoylation.

High Resolution Ion Mobility Enables the Structural Characterization of Atropisomers of GDC-6036, a KRAS G12C Covalent Inhibitor.

GDC-6036 is a covalent KRAS G12C inhibitor that demonstrates high potency and selectivity. Structurally, GDC-6036 consists of several motifs that make the analytical characterization of this molecule challenging, including a highly basic pyrrolidine motif bonded to a quinazoline ring via an ether bond and an atropisomeric carbon-carbon bond between functionalized pyridine and quinazoline groups. Structurally, the desired atropisomer was synthesized via an atroposelective Negishi coupling with very high yield. However, having a direct way to analyze and confirm the presence of the atropisomeric species remained challenging in routine analytical workflows. In this study, both variable temperature nuclear magnetic resonance (VT-NMR) and two different approaches of in-line ion mobility coupled to liquid chromatography mass spectrometry (LC-MS) workflows were evaluated for the characterization of GDC-6036 and its undesired atropisomer (Compound B) to support synthetic route development. Briefly, both VT-NMR and traveling wave ion mobility spectrometry (TWIMS) enabled by structures for lossless ion manipulation (SLIM) technology coupled to high resolution MS (HRMS) are able to elucidate the structures of the atropisomers in a complex mixture. Drift tube IMS (DTIMS) was also evaluated, but lacked the resolving power to demonstrate separation between the two species in a mixture, but did show slight differences in their arrival times when multiplexed and injected separately. The determined resolving power (Rp) by multiplexing the ions via DTIMS was 67.3 and 60.5 for GDC-6036 and Compound B, respectively, while the two peak resolving power (Rpp) was determined to be 0.41, indicating inadequate resolution between the two species. Alternatively, the SLIM-IM studies showed Rp of 103.8 and 99.4, with a Rpp of 2.64, indicating good separation between the atropisomers. Furthermore, the CCS/z for GDC-6036 and Compound B was determined to be 231.2 Å2/z and 235.0 Å2/z, respectively. Quantitative experiments demonstrate linearity (R2 >0.99) for both GDC-6036 and Compound B while maintaining separation via SLIM-IM. Spike recoveries of one atropisomer relative to the other yielded strong recoveries (98.7% to 102.5%) while maintaining reproducibility (<7% RSD). The study herein describes the analytical process for evaluating new technologies and strategies for implementation in routine biopharmaceutical characterization workflows.

Native mass spectrometry of membrane protein-lipid interactions in different detergent environments.

Native mass spectrometry (MS) is revealing the role of specific lipids in modulating membrane protein structure and function. Membrane proteins solubilized in detergents are often introduced into the mass spectrometer; however, commonly used detergents for structural studies, such as dodecylmaltoside, tend to generate highly charged ions, leading to protein unfolding, thereby diminishing their utility for characterizing protein-lipid interactions. Thus, there is a critical need to develop approaches to investigate protein-lipid interactions in different detergents. Here, we demonstrate how charge-reducing molecules, such as spermine and trimethylamine-N-oxide, enable characterization of lipid binding to the bacterial water channel (AqpZ) and ammonia channel (AmtB) in complex with regulatory protein GlnK in different detergent environments. We find protein-lipid interactions are not only protein-dependent but can also be influenced by the detergent and type of charge-reducing molecule. AqpZ-lipid interactions are enhanced in LDAO (n-dodecyl-N,N-dimethylamine-N-oxide), whereas the interaction of AmtB-GlnK with lipids is comparable among different detergents. A fluorescent lipid binding assay also shows detergent dependence for AqpZ-lipid interactions, consistent with results from native MS. Taken together, native MS will play a pivotal role in establishing optimal experimental parameters that will be invaluable for various applications, such as drug discovery, as well as biochemical and structural investigations.

A cross sectional pilot study utilising STrain Analysis and Mapping of the Plantar Surface (STAMPS) to measure plantar load characteristics within a healthy population.

BACKGROUND: No in-shoe systems, measuring both components of plantar load (plantar pressure and shear stress) are available for use in patients with diabetes. The STAMPS (STrain Analysis and Mapping of the Plantar Surface) system utilises digital image correlation (DIC) to determine the strain sustained by a deformable insole, providing a more complete understanding of plantar shear load at the foot-surface interface. RESEARCH QUESTIONS: What is the normal range and pattern of strain at the foot-surface interface within a healthy population as measured by the STAMPS system? Is STAMPS a valid tool to measure the effects of plantar load? METHODS: A cross-sectional study of healthy participants was undertaken. Healthy adults without foot pathology or diabetes were included. Participants walked 20 steps with the STAMPS insole in a standardised shoe. Participants also walked 10 m with the Novel Pedar® plantar pressure measurement insole within the standardised shoe. Both measurements were repeated three times. Outcomes of interest were global and regional values for peak resultant strain (SMAG) and peak plantar pressure (PPP). RESULTS: In 18 participants, median peak SMAG and PPP were 35.01 % and 410.6kPa respectively. The regions of the hallux and heel sustained the highest SMAG (29.31 % (IQR 24.56-31.39) and 20.50 % (IQR 15.59-24.12) respectively) and PPP (344.8kPa (IQR 268.3 - 452.5) and 279.3kPa (IQR 231.3-302.1) respectively). SMAG was moderately correlated with PPP (r= 0.65, p < 0.001). Peak SMAG was located at the hallux in 55.6 % of participants, at the 1st metatarsal head (MTH) in 16.7 %, the heel in 16.7 %, toes 3-5 in 11.1 % and the MTH2 in 5.6 %. SIGNIFICANCE: The results demonstrate the STAMPS system is a valid tool to measure plantar strain. Further studies are required to investigate the effects of elevated strain and the relationship with diabetic foot ulcer formation.

Water Plays Key Roles in Stabilities of Wild Type and Mutant Transthyretin Complexes.

Transthyretin (TTR), a 56 kDa homotetramer that is involved in the transport of thyroxine and retinol, has been linked to amyloidosis through disassembly of tetramers to form monomers, dimers, and trimers that then reassemble into higher order oligomers and/or fibrils. Hybrid TTR (hTTR) tetramers are found in heterozygous individuals that express both wild type TTR (wt-TTR) and mutant TTR (mTTR) forms of the protein, and these states display increased rates of amyloidosis. Here we monitor subunit exchange (SUE) reactions involving homomeric and mixed tetramers using high resolution native mass spectrometry (nMS). Our results show evidence that differences in TTR primary structure alter tetramer stabilities, and hTTR products can form spontaneously by SUE reactions. In addition, we find that solution temperature has strong effects on TTR tetramer stabilities and formation of SUE products. Lower temperatures promote formation of hTTR tetramers containing L55P and V30M subunits, whereas small effects on the formation of hTTR tetramers containing F87A and T119M subunits are observed. We hypothesize that the observed temperature dependent stabilities and subsequent SUE behavior are a result of perturbations to the network of "two kinds of water": hydrating and structure stabilizing water molecules (Spyrakis et al. J. Med. Chem. 2017, 60 (16), 6781-6827; Xu et al. Soft Matter 2012, 8, 324-336) that stabilize wt-TTR and mTTR tetramers. The results presented in this work illustrate the utility of high resolution nMS for studies of the structures, stabilities, and dynamics of protein complexes that directly influence SUE reactions.

CD38+ Alveolar macrophages mediate early control of M. tuberculosis proliferation in the lung.

Tuberculosis, caused by M.tuberculosis (Mtb), remains an enduring global health challenge, especially given the limited efficacy of current therapeutic interventions. Much of existing research has focused on immune failure as a driver of tuberculosis. However, the crucial role of host macrophage biology in controlling the disease remains underappreciated. While we have gained deeper insights into how alveolar macrophages (AMs) interact with Mtb, the precise AM subsets that mediate protection and potentially prevent tuberculosis progression have yet to be identified. In this study, we employed multi-modal scRNA-seq analyses to evaluate the functional roles of diverse macrophage subpopulations across different infection timepoints, allowing us to delineate the dynamic landscape of controller and permissive AM populations during the course of infection. Our analyses at specific time-intervals post-Mtb challenge revealed macrophage populations transitioning between distinct anti- and pro-inflammatory states. Notably, early in Mtb infection, CD38- AMs showed a muted response. As infection progressed, we observed a phenotypic shift in AMs, with CD38+ monocyte-derived AMs (moAMs) and a subset of tissue-resident AMs (TR-AMs) emerging as significant controllers of bacterial growth. Furthermore, scATAC-seq analysis of naïve lungs demonstrated that CD38+ TR-AMs possessed a distinct chromatin signature prior to infection, indicative of epigenetic priming and predisposition to a pro-inflammatory response. BCG intranasal immunization increased the numbers of CD38+ macrophages, substantially enhancing their capability to restrict Mtb growth. Collectively, our findings emphasize the pivotal, dynamic roles of different macrophage subsets in TB infection and reveal rational pathways for the development of improved vaccines and immunotherapeutic strategies.

Comparing Unmet Service Needs Between Rural and Urban Family Caregivers of People Living With Alzheimer's Disease and Related Dementias: A Multisite Study.

BACKGROUND AND OBJECTIVES: The scarcity of resources and available caregiving services in rural areas in the United States has been well documented. However, less research has compared unmet service needs between caregivers of people with Alzheimer's disease and related dementias (ADRD) in rural versus urban areas. RESEARCH DESIGN AND METHODS: Using semistructured interviews guided by theories of health service use and dependent care, we interviewed 20 family caregivers residing in rural areas of Western North Carolina and 18 caregivers within the urban setting of Houston, Texas, and compared their unmet service needs and contextual factors that facilitate their service use. RESULTS: Thematic analyses revealed similar unmet service needs among rural and urban caregivers; however, the ways they approached and solved their challenges differed. Caregivers in rural areas wished for more information and caregiver support whereas urban caregivers looked for information they needed until they found the answers. Rural caregivers expressed guilt about using services because they felt they were limited and zero-sum whereas urban caregivers shared available resources so that other caregivers could use them as well. Unmet service needs for urban caregivers included more racially and ethnically specific services for people with ADRD in their ethnic-specific languages and foods while rural caregivers' cultural needs were not racially and ethnically specific but for more place-specific services. DISCUSSION AND IMPLICATIONS: Recommendations for rural caregivers included utilizing online and virtual opportunities and expanding their reach across the United States. For urban caregivers, increasing culturally tailored service options would likely increase access and use.

Minimal clinically important differences in patient-reported outcomes after coronary artery bypass surgery in the arterial revascularization trial.

OBJECTIVES: This article identifies minimal clinically important differences (MCIDs) in quality of life (QoL) measures among patients who had coronary artery bypass grafting (CABG) and were enrolled in the arterial revascularization trial (ART). METHODS AND RESULTS: The European Quality of Life-5 Dimensions (EQ-5D) and the Short Form Health Survey 36-Item (SF-36) physical component (PC) and mental component (MC) scores were recorded at baseline, 5 years and 10 years in ART. The MCIDs were calculated as changes in QoL scores anchored to 1-class improvement in the New York Heart Association functional class and Canadian Cardiovascular Society scale at 5 years. Cox proportional hazard models were used to evaluate associations between MCIDs and mortality. Patient cohorts were examined for the SF-36 PC (N = 2671), SF-36 MC (N = 2815) and EQ-5D (N = 2943) measures, respectively. All QoL scores significantly improved after CABG compared to baseline. When anchored to the New York Heart Association, the MCID at 5 years was 17 (95% confidence interval: 17-20) for SF-36 PC, 14 (14-17) for the SF-36 MC and 0.12 (0.12-0.15) for EQ-5D. Using the Canadian Cardiovascular Society scale as an anchor, the MCID at 5 years was 15 (15-17) for the SF-36 PC, 12 (13-15) for the SF-36 MC and 0.12 (0.11-0.14) for the EQ-5D. The MCIDs for SF-36 PC and EQ-5D at 5 years were associated with a lower risk of mortality at the 10-year follow-up point after surgery. CONCLUSIONS: MCIDs for CABG patients have been identified. These thresholds may have direct clinical applications in monitoring patients during follow-up and in designing new trials that include QoL as a primary study outcome. CLINICAL TRIAL REGISTRATION NUMBER: ISRCTN46552265.

Host stress drives tolerance and persistence: The bane of anti-microbial therapeutics.

Antibiotic resistance, typically associated with genetic changes within a bacterial population, is a frequent contributor to antibiotic treatment failures. Antibiotic persistence and tolerance, which we collectively term recalcitrance, represent transient phenotypic changes in the bacterial population that prolong survival in the presence of typically lethal concentrations of antibiotics. Antibiotic recalcitrance is challenging to detect and investigate-traditionally studied under in vitro conditions, our understanding during infection and its contribution to antibiotic failure is limited. Recently, significant progress has been made in the study of antibiotic-recalcitrant populations in pathogenic species, including Mycobacterium tuberculosis, Staphylococcus aureus, Salmonella enterica, and Yersiniae, in the context of the host environment. Despite the diversity of these pathogens and infection models, shared signals and responses promote recalcitrance, and common features and vulnerabilities of persisters and tolerant bacteria have emerged. These will be discussed here, along with progress toward developing therapeutic interventions to better treat recalcitrant pathogens.

Variation in Systemic Antibiotic Treatment for Diabetic Foot Osteomyelitis in England and Wales: A Multi-Centre Case Review.

Background: Diabetic foot osteomyelitis (DFO) is a major complication and can lead to significant morbidity and mortality. Systemic antibiotic therapy is often initiated first line to achieve quiescence of infection. To perform a multi-centre case review of systemic antibiotic intervention to treat adults with DFO in England and Wales and compare with national guidelines 'Diabetic foot problems: prevention and management'. Methods: Eight centres from England and Wales retrospectively collated data from a minimum of five adults (aged ≥ 18 years) from electronic case records. All patients were treated with systemic antibiotics following a new diagnosis of DFO (1 June 2021-31 December 2021). Results: 40 patients (35 males and 5 females) were included; the mean age was 62.3 years (standard deviation (SD) 13.0). Patients commenced systemic oral 14 (35%) or intravenous 26 (65%) antibiotic therapy following a new diagnosis of DFO. Twenty-seven (67.5%) patients were medically or surgically managed in the 12-week period with clinical quiescence of infection. Twenty-one patients (52.5%) had no recurrence of DFO infection within 12 weeks; seventeen (42.5%) of these patients had clinical quiescence of infection with systemic antibiotics alone without surgical intervention and nine (22.5%) of these cases had no recurrence of DFO. There were no cases of major amputation or death. All centres showed significant in-centre variability in systemic antibiotic management; variability was reported in the clinical and quantity indicators specifically to antibiotic selection, single versus dual therapy, mode of delivery and duration of treatment. Conclusions: This case review identifies there is existing variation when treating adults with systemic antibiotics for DFO. Further national guidance is required to standardise service delivery and care to improve patient outcomes.

Clinical perspectives on sampling and processing approaches for the management of infection in diabetic foot ulceration: A qualitative study.

Diabetic foot ulcers (DFUs) often become infected and are treated with antimicrobials, with samples collected to inform care. Swab samples are easier than tissue sampling but report fewer organisms. Compared with culture and sensitivity (C&S) methods, molecular microbiology identifies more organisms. Clinician perspectives on sampling and processing are unknown. We explored clinician perspectives on DFU sampling-tissue samples/wound swabs-and on processing techniques, culture and sensitivity or molecular techniques. The latter provides information on organisms which have not survived transport to the laboratory for culture. We solicited feedback on molecular microbiology reports. Qualitative study using semi-structured interview, with analysis using a Framework approach. CODIFI2 clinicians from UK DFU clinics. Seven consultants agreed to take part. They reported, overall, a preference for tissue samples over swabbing. Clinicians were not confident replacing C&S with molecular microbiology as the approach to reporting was unfamiliar. The study was small and did not recruit any podiatrists or nurses, who may have discipline-specific attitudes or perspectives on DFU care. Both sampling approaches appear to be used by clinicians. Molecular microbiology reports would not be, at present, suitable for replacement of traditional culture and sensitivity.

Bortezomib Inhibits Open Configurations of the 20S Proteasome.

Bortezomib, a small dipeptide-like molecule, is a proteasome inhibitor used widely in the treatment of myeloma and lymphoma. This molecule reacts with threonine side chains near the center of the 20S proteasome and disrupts proteostasis by blocking enzymatic sites that are responsible for protein degradation. In this work, we use novel mass-spectrometry-based techniques to examine the influence of bortezomib on the structures and stabilities of the 20S core particle. These studies indicate that bortezomib binding dramatically favors compact 20S structures (in which the axial gate is closed) over larger structures (in which the axial gate is open)─suppressing gate opening by factors of at least ∼400 to 1300 over the temperature range that is studied. Thus, bortezomib may also restrict degradation in the 20S proteasome by preventing substrates from entering the catalytic pore. That bortezomib influences structures at the entrance region of the pore at such a long distance (∼65 to 75 Å) from its binding sites raises a number of interesting biophysical issues.

Genome-wide screen of Mycobacterium tuberculosis- infected macrophages identified the GID/CTLH complex as a determinant of intracellular bacterial growth.

The eukaryotic GID/CTLH complex is a highly conserved E3 ubiquitin ligase involved in a broad range of biological processes. However, a role of this complex in host antimicrobial defenses has not been described. We exploited Mycobacterium tuberculosis ( Mtb ) induced cytotoxicity in macrophages in a FACS based CRISPR genetic screen to identify host determinants of intracellular Mtb growth restriction. Our screen identified 5 ( GID8 , YPEL5 , WDR26 , UBE2H , MAEA ) of the 10 predicted members of the GID/CTLH complex as determinants of intracellular growth of both Mtb and Salmonella serovar Typhimurium. We show that the antimicrobial properties of the GID/CTLH complex knockdown macrophages are mediated by enhanced GABAergic signaling, activated AMPK, increased autophagic flux and resistance to cell death. Meanwhile, Mtb isolated from GID/CTLH knockdown macrophages are nutritionally starved and oxidatively stressed. Our study identifies the GID/CTLH complex activity as broadly suppressive of host antimicrobial responses against intracellular bacterial infections.