Continuous glucose monitoring for glycaemic control and cardiovascular risk reduction in patients with type 2 diabetes not on insulin therapy: A clinical trial.

AIM: To evaluate the impact of the Dexcom G6 continuous glucose monitoring (CGM) device on glycaemic control and cardiometabolic risk in patients with type 2 diabetes mellitus (T2DM) at high cardiovascular risk who are not on insulin therapy. MATERIALS AND METHODS: Adults with T2DM with glycated haemoglobin (HbA1c) >7% and body mass index (BMI) ≥30 kg/m2 not using insulin were enrolled in a two-phase cross-over study. In phase 1, CGM data were blinded, and participants performed standard glucose self-monitoring. In phase 2, the CGM data were unblinded, and CGM, demographic and cardiovascular risk factor data were collected through 90 days of follow-up and compared using paired tests. RESULTS: Forty-seven participants were included (44% women; 34% Black; mean age 63 years; BMI 37 kg/m2; HbA1c 8.4%; 10-year predicted atherosclerotic cardiovascular disease risk 24.0%). CGM use was associated with a reduction in average glucose (184.0 to 147.2 mg/dl, p < .001), an increase in time in range (57.8 to 82.8%, p < .001) and a trend towards lower glucose variability (26.2 to 23.8%). There were significant reductions in HbA1c, BMI, triglycerides, blood pressure, total cholesterol, diabetes distress and 10-year predicted risk for atherosclerotic cardiovascular disease (p < .05 for all) and an increase in prescriptions for sodium-glucose cotransporter 2 inhibitors (36.2 to 83.0%) and glucagon-like peptide-1 receptor agonists (42.5 to 87.2%, p < .001 for both). CONCLUSIONS: Dexcom G6 CGM was associated with improved glycaemic control and cardiometabolic risk in patients with T2DM who were not on insulin. CGM can be a safe and effective tool to improve diabetes management in patients at high risk for adverse cardiovascular outcomes.

Highly Selective Aptamer-Molecularly Imprinted Polymer Hybrids for Recognition of SARS-CoV-2 Spike Protein Variants.

Virus recognition has been driven to the forefront of molecular recognition research due to the COVID-19 pandemic. Development of highly sensitive recognition elements, both natural and synthetic is critical to facing such a global issue. However, as viruses mutate, it is possible for their recognition to wane through changes in the target substrate, which can lead to detection avoidance and increased false negatives. Likewise, the ability to detect specific variants is of great interest for clinical analysis of all viruses. Here, a hybrid aptamer-molecularly imprinted polymer (aptaMIP), that maintains selective recognition for the spike protein template across various mutations, while improving performance over individual aptamer or MIP components (which themselves demonstrate excellent performance). The aptaMIP exhibits an equilibrium dissociation constant of 1.61 nM toward its template which matches or exceeds published examples of imprinting of the spike protein. The work here demonstrates that "fixing" the aptamer within a polymeric scaffold increases its capability to selectivity recognize its original target and points toward a methodology that will allow variant selective molecular recognition with exceptional affinity.

Delayed Pericardial Effusion Following Left Atrial Appendage Closure: A 5-Year Single-Center Experience.

BACKGROUND: Though uncommon, pericardial effusion and cardiac tamponade are serious complications of left atrial appendage closure (LAAC). There are few data related to delayed pericardial effusions from this procedure. METHODS: This is a single-center prospective analysis of 369 patients who underwent LAAC from December 2016 to March 2022 at a large teaching hospital. We compared patients who developed effusion (n = 5) to patients who did not (n = 364) to determine if there were any factors that predispose patients to developing acute (AEs) or delayed pericardial effusions (DEs). We compared patient characteristics, procedural data, and complications. Unadjusted, stepwise multivariate logistic regression was performed. RESULTS: A total of 369 patients underwent LAAC. Of these, 5 patients (1.4%) developed pericardial effusion. Patients in both groups (pericardial effusion vs non-effusion) had similar patient and procedural characteristics. Patients in both groups were older (mean age, 78.4 ± 7.8 years in the effusion group vs 76.3 ± 8.5 years in the non-effusion group; P=.50) and white (60% in the effusion group vs 90.1% in the non-effusion group). CHA2DS2-VASc (4.2 ± 1.1 vs 4.5 ± 1.4; P=.67) and HAS-BLED (3.4 ± 0.5 vs 3.7 ± 0.9; P=.53) scores were similar in the effusion group vs the non-effusion group, respectively. Gastrointestinal bleeding was the most common procedural indication in both groups (80% in the effusion group vs 53.6% in the non-effusion group; P=.23). The majority of the patients in both groups had successful implantation in the first attempt, with the 27-mm device the most commonly used size. There was no significant difference in procedural duration (67 minutes in the effusion group vs 75 minutes in the non-effusion group; P=.16). Among patients who received the Watchman Legacy device, 2 patients developed AEs and no patients had DEs. Of those receiving the Watchman FLX device, 1 patient developed AE and 2 patients developed DEs. All of the patients with effusions had successful recovery. CONCLUSION: In this 5-year, single-center experience, DEs were uncommon and potentially related to LAA device anchor microperforation. No statistically significant risk factors predisposing patients to pericardial effusions were identified in our analysis.

Human Serum Alters the Metabolism and Antibiotic Susceptibility of Staphylococcus aureus.

Staphylococcus aureus is a common source of hospital-acquired bacterial infections, where the emergence of antibiotic resistance is a serious human health concern. Most investigations into S. aureus virulence and antibiotic resistance have relied on in vitro cultivation conditions and optimized media formulations. However, S. aureus can survive and adapt to a hostile host environment or antibiotic treatments by rapidly adjusting its metabolic activity. To assess this metabolic response, S. aureus strains susceptible and nonsusceptible to daptomycin were cultivated in medium supplemented with 55% serum to more closely approximate in vivo conditions. Growth analyses, MIC testing, and NMR-based metabolomics determined that serum decreased daptomycin susceptibility and altered metabolism in S. aureus. Both S. aureus strains exhibited altered amino acid biosynthesis and catabolism, enhanced fermentation, and a modified salt tolerance response. The observation that growth conditions defined an adaptive metabolic response to antibiotics by S. aureus may be a critical consideration for designing an effective drug discovery study.

Novel computed tomography angiography-based sizing methodology for WATCHMAN FLX device in left atrial appendage closure.

BACKGROUND: While there is recent data suggesting an advantage of computed tomography angiography (CTA) over transesophageal echocardiography (TEE) for preprocedural left atrial appendage closure (LAAC) planning, there is limited published experience for sizing strategies. Device sizing for LAAC may be challenging and noninvasive algorithms that improve this selection process are warranted. OBJECTIVES: We sought to evaluate the safety and the feasibility for the implementation of a novel CTA-based sizing methodology for WATCHMAN™ FLX device in a series of patients undergoing LAAC using the TruPlan™ software package. METHODS: A prospective analysis of 136 consecutive patients who underwent LAAC over a 12-month period in a single, large academic hospital in the United States was conducted. CTA-guided preprocedural planning and intracardiac echocardiography (ICE) was performed in all. Procedural success, adverse events, length of procedure, number of devices used, and length of stay were evaluated. RESULTS: A total of 136 patients who underwent LAAC procedure with WATCHMAN™ FLX platform between October 1, 2020 until September 30, 2021 were included. The pre-specified protocol using CTA and ICE was implemented in all patients (100%). Mean CHA2 DS2 VASc score was 4.4 ± 1.3 and the mean HAS-BLED score was 3.9 ± 0.8. ICE-guided 100% transseptal puncture success rate was 100% with 98.5% of overall procedural success rate. Preprocedural CTA sizing strategy accurately predicted the implanted size in 91.1% of patients. Ten patients (7.4%) required another sized device and 2 cases were aborted. At 45-day follow-up, only 1 patient (0.7%) had significant peri-device leak (≥5 mm) on TEE. CONCLUSIONS: CTA-based preprocedural sizing methodology for WATCHMAN™ FLX in LAAC was safe, feasible and associated with excellent procedural outcomes. Further studies are warranted to confirm if the features specific to TruPlan™ may reduce the number of deployment attempts, the number of devices utilized in the procedure, and the risk of complications.

Metabolic changes associated with adaptive resistance to daptomycin in Streptococcus mitis-oralis.

BACKGROUND: Viridans group streptococci of the Streptococcus mitis-oralis subgroup are important endovascular pathogens. They can rapidly develop high-level and durable non-susceptibility to daptomycin both in vitro and in vivo upon exposure to daptomycin. Two consistent genetic adaptations associated with this phenotype (i.e., mutations in cdsA and pgsA) lead to the depletion of the phospholipids, phosphatidylglycerol and cardiolipin, from the bacterial membrane. Such alterations in phospholipid biosynthesis will modify carbon flow and change the bacterial metabolic status. To determine the metabolic differences between daptomycin-susceptible and non-susceptible bacteria, the physiology and metabolomes of S. mitis-oralis strains 351 (daptomycin-susceptible) and 351-D10 (daptomycin non-susceptible) were analyzed. S. mitis-oralis strain 351-D10 was made daptomycin non-susceptible through serial passage in the presence of daptomycin. RESULTS: Daptomycin non-susceptible S. mitis-oralis had significant alterations in glucose catabolism and a re-balancing of the redox status through amino acid biosynthesis relative to daptomycin susceptible S. mitis-oralis. These changes were accompanied by a reduced capacity to generate biomass, creating a fitness cost in exchange for daptomycin non-susceptibility. CONCLUSIONS: S. mitis-oralis metabolism is altered in daptomycin non-susceptible bacteria relative to the daptomycin susceptible parent strain. As demonstrated in Staphylococcus aureus, inhibiting the metabolic changes that facilitate the transition from a daptomycin susceptible state to a non-susceptible one, inhibits daptomycin non-susceptibility. By preventing these metabolic adaptations in S. mitis-oralis, it should be possible to deter the formation of daptomycin non-susceptibility.

Type 2 Diabetes and Chronic Conditions Disparities in Medicare Beneficiaries in the State of Michigan.

BACKGROUND: This study aimed to describe the prevalence of type 2 diabetes and combinations of multiple chronic conditions (MCCs) that are leading causes of death (LCD) and confirm that disparities exist between groups based on race and sex. MATERIALS AND METHODS: We conducted a retrospective cohort study using 2012 Medicare claims data from beneficiaries with type 2 diabetes over the age of 65 in the state of Michigan. RESULTS: Female beneficiaries have type 2 diabetes and 1 or more MCCs that are LCD more often than males. Most type 2 diabetes patients have diabetes alone without MCCs, while a large proportion have at least 1 additional chronic condition that is a LCD. One in 3 patients have 3 or more chronic conditions. The most prevalent type 2 diabetes coexisting MCCs are congestive heart failure (CHF), chronic obstructive pulmonary disease and chronic kidney disease. Asian/Pacific Islanders have the highest prevalence of type 2 diabetes without MCCs, and the highest prevalence of diabetes plus CHF. While fewer black beneficiaries have diabetes alone or 1 additional MCC, the prevalence of 3 or more MCCs in blacks generally exceeds the prevalence in other races. In beneficiaries with newly diagnosed type 2 diabetes, chronic obstructive pulmonary disease and CHF are the first new chronic conditions to be diagnosed after an initial type 2 diabetes diagnosis. CONCLUSIONS: Race and sex disparities occur in the prevalence of type 2 diabetes and MCCs that are LCD in Medicare beneficiaries in the state of Michigan.

Aging influences cerebrovascular myogenic reactivity and BK channel function in a sex-specific manner.

AIMS: The myogenic reactivity of the middle cerebral arteries (MCA) protects the brain by altering the diameter in response to changes in lumen pressure. Large conductance potassium (BK) channels are known to regulate the myogenic reactivity, yet, it is not clear how aging alters the myogenic reactivity via the BK channel in males and females. Thus, we hypothesize that age-associated changes in BK channel subunits modulate the myogenic reactivity in a sex-specific manner. METHODS AND RESULTS: We used vascular reactivity, patch-clamp, and biochemical methods to measure myogenic reactivity, BK channel function, and expression, respectively in cerebral vessels of adult and aged male and female Sprague Dawley rats. Our results suggest that aging and ovariectomy (OVX) exaggerated the myogenic reactivity of MCA in females but attenuated it in males. Aging induced outward eutrophic remodelling in females but inward hypertrophic remodelling in males. Aging decreased total, Kv, BK channel currents, and spontaneous transient outward currents (STOC) in vascular smooth muscle cells isolated from females, but not in males. Aging increased BKα subunit mRNA and protein both in males and females. However, aging decreased BKß1 subunit protein and mRNA in females only. In males, BKß1 mRNA is increased, but protein is decreased. Iberiotoxin-induced MCA constriction is lower in aged females but higher in aged males. Activation of BKα (10 µM NS1619) and BKß1 (10 µM S-Equol) subunits failed to increase STOCs and were unable to decrease the myogenic reactivity of MCA in aged female but not in aged male rats. OVX decreased, but chronic supplementation of oestradiol restored BK channel expression and function. CONCLUSION: Overall our results suggest that aging or OVX-associated downregulation of the BKß1 expression and function in females results in exaggerated myogenic reactivity of MCA. However, age-associated increase in BK channel function in males attenuated myogenic reactivity of MCA.

Metabolic interventions for the prevention and treatment of daptomycin non-susceptibility in Staphylococcus aureus.

BACKGROUND: A major developing problem in the treatment of Staphylococcus aureus infections is the emergence of resistance during treatment with daptomycin. Previous metabolomic analyses of isogenic S. aureus strains prior to and after evolution into a daptomycin non-susceptible (DapNS) state provided important metabolic information about this transition (e.g. perturbations of the tricarboxylic acid cycle). OBJECTIVES: To assess the significance of these metabolic changes, in vitro susceptibility to daptomycin was determined in daptomycin-susceptible (DapS) and DapNSS. aureus strains cultivated with metabolic inhibitors targeting these changes. METHODS: Only inhibitors that are approved for use in humans were chosen (i.e. fosfomycin, valproate, trimetazidine and 6-mercaptopurine) to assess the importance of metabolic pathways for daptomycin non-susceptibility. The ability of these inhibitors to forestall the emergence of DapNS strains was also assessed. RESULTS: The combination of daptomycin and fosfomycin synergistically killed both DapS and DapNS strains in vitro and enhanced the in vivo outcome against a DapNS strain in experimental endocarditis. Interestingly, fosfomycin acts on the peptidoglycan biosynthetic enzyme UDP-N-acetylglucosamine enolpyruvyl transferase (MurA); however, it also had a significant effect on the enzymatic activity of enolase, an essential enzyme in S. aureus. While fosfomycin acted synergistically with daptomycin, it failed to prevent the in vitro evolution of daptomycin non-susceptibility. In contrast, trimetazidine, an anti-angina drug that stimulates glucose oxidation, abolished the ability of DapSS. aureus strains to transition to a DapNS state. CONCLUSIONS: These data reveal that metabolic adaptations associated with DapNS strains can be targeted to prevent the emergence of and/or reverse pre-existing resistance to daptomycin.

Coordinated regulation of transcription by CcpA and the Staphylococcus aureus two-component system HptRS.

The success of Staphylococcus aureus as a pathogen is due in part to its ability to adapt to changing environmental conditions using signal transduction pathways, such as metabolite- responsive regulators and two-component systems. S. aureus has a two-component system encoded by the gene pair sav0224 (hptS) and sav0223 (hptR) that regulate the hexose phosphate transport (uhpT) system in response to extracellular glucose-6-phosphate. Glycolytic intermediates such as glucose-6-phosphate are important carbon sources that also modulate the activity of the global metabolite-responsive transcriptional regulator CcpA. Because uhpT has a putative CcpA binding site in its promoter and it is regulated by HptR, it was hypothesized the regulons of CcpA and HptR might intersect. To determine if the regulatory domains of CcpA and HptRS overlap, ccpA was deleted in strains SA564 and SA564-ΔhptRS and growth, metabolic, proteomic, and transcriptional differences were assessed. As expected, CcpA represses hptS and hptR in a glucose dependent manner; however, upon CcpA derepression, the HptRS system functions as a transcriptional activator of metabolic genes within the CcpA regulon. Importantly, inactivation of ccpA and hptRS altered sensitivity to fosfomycin and ampicillin in the absence of exogenous glucose-6-phosphate, indicating that both CcpA and HptRS modulate antibiotic susceptibility.

Noncontact Strain Monitoring of Osseointegrated Prostheses.

The objective of this study was to develop a noncontact, noninvasive, imaging system for monitoring the strain and deformation states of osseointegrated prostheses. The proposed sensing methodology comprised of two parts. First, a passive thin film was designed such that its electrical permittivity increases in tandem with applied tensile loading and decreases while unloading. It was found that patterning the thin films could enhance their dielectric property's sensitivity to strain. The film can be deposited onto prosthesis surfaces as an external coating prior to implant. Second, an electrical capacitance tomography (ECT) measurement technique and reconstruction algorithm were implemented to capture strain-induced changes in the dielectric property of nanocomposite-coated prosthesis phantoms when subjected to different loading scenarios. The preliminary results showed that ECT, when coupled with strain-sensitive nanocomposites, could quantify the strain-induced changes in the dielectric property of thin film-coated prosthesis phantoms. The results suggested that ECT coupled with embedded thin films could serve as a new noncontact strain sensing method for scenarios when tethered strain sensors cannot be used or instrumented, especially in the case of osseointegrated prostheses.

UNG protects B cells from AID-induced telomere loss.

Activation-induced deaminase (AID) initiates antibody gene diversification by creating G:U mismatches in the immunoglobulin loci. However, AID also deaminates nonimmunoglobulin genes, and failure to faithfully repair these off-target lesions can cause B cell lymphoma. In this study, we identify a mechanism by which processing of G:U produced by AID at the telomeres can eliminate B cells at risk of genomic instability. We show that telomeres are off-target substrates of AID and that B cell proliferation depends on protective repair by uracil-DNA glycosylase (UNG). In contrast, in the absence of UNG activity, deleterious processing by mismatch repair leads to telomere loss and defective cell proliferation. Indeed, we show that UNG deficiency reduces B cell clonal expansion in the germinal center in mice and blocks the proliferation of tumor B cells expressing AID. We propose that AID-induced damage at telomeres acts as a fail-safe mechanism to limit the tumor promoting activity of AID when it overwhelms uracil excision repair.

Staphylococcus aureus metabolic adaptations during the transition from a daptomycin susceptibility phenotype to a daptomycin nonsusceptibility phenotype.

Staphylococcus aureus is a major cause of nosocomial and community-acquired infections. The success of S. aureus as a pathogen is due in part to its many virulence determinants and resistance to antimicrobials. In particular, methicillin-resistant S. aureus has emerged as a major cause of infections and led to increased use of the antibiotics vancomycin and daptomycin, which has increased the isolation of vancomycin-intermediate S. aureus and daptomycin-nonsusceptible S. aureus strains. The most common mechanism by which S. aureus acquires intermediate resistance to antibiotics is by adapting its physiology and metabolism to permit growth in the presence of these antibiotics, a process known as adaptive resistance. To better understand the physiological and metabolic changes associated with adaptive resistance, six daptomycin-susceptible and -nonsusceptible isogenic strain pairs were examined for changes in growth, competitive fitness, and metabolic alterations. Interestingly, daptomycin nonsusceptibility coincides with a slightly delayed transition to the postexponential growth phase and alterations in metabolism. Specifically, daptomycin-nonsusceptible strains have decreased tricarboxylic acid cycle activity, which correlates with increased synthesis of pyrimidines and purines and increased carbon flow to pathways associated with wall teichoic acid and peptidoglycan biosynthesis. Importantly, these data provided an opportunity to alter the daptomycin nonsusceptibility phenotype by manipulating bacterial metabolism, a first step in developing compounds that target metabolic pathways that can be used in combination with daptomycin to reduce treatment failures.

Cyclic di-GMP-dependent signaling pathways in the pathogenic Firmicute Listeria monocytogenes.

We characterized key components and major targets of the c-di-GMP signaling pathways in the foodborne pathogen Listeria monocytogenes, identified a new c-di-GMP-inducible exopolysaccharide responsible for motility inhibition, cell aggregation, and enhanced tolerance to disinfectants and desiccation, and provided first insights into the role of c-di-GMP signaling in listerial virulence. Genome-wide genetic and biochemical analyses of c-di-GMP signaling pathways revealed that L. monocytogenes has three GGDEF domain proteins, DgcA (Lmo1911), DgcB (Lmo1912) and DgcC (Lmo2174), that possess diguanylate cyclase activity, and three EAL domain proteins, PdeB (Lmo0131), PdeC (Lmo1914) and PdeD (Lmo0111), that possess c-di-GMP phosphodiesterase activity. Deletion of all phosphodiesterase genes (ΔpdeB/C/D) or expression of a heterologous diguanylate cyclase stimulated production of a previously unknown exopolysaccharide. The synthesis of this exopolysaccharide was attributed to the pssA-E (lmo0527-0531) gene cluster. The last gene of the cluster encodes the fourth listerial GGDEF domain protein, PssE, that functions as an I-site c-di-GMP receptor essential for exopolysaccharide synthesis. The c-di-GMP-inducible exopolysaccharide causes cell aggregation in minimal medium and impairs bacterial migration in semi-solid agar, however, it does not promote biofilm formation on abiotic surfaces. The exopolysaccharide also greatly enhances bacterial tolerance to commonly used disinfectants as well as desiccation, which may contribute to survival of L. monocytogenes on contaminated food products and in food-processing facilities. The exopolysaccharide and another, as yet unknown c-di-GMP-dependent target, drastically decrease listerial invasiveness in enterocytes in vitro, and lower pathogen load in the liver and gallbladder of mice infected via an oral route, which suggests that elevated c-di-GMP levels play an overall negative role in listerial virulence.

Epidemiology of vitamin D deficiency in children presenting to a pediatric orthopaedic service in the UK.

BACKGROUND: Vitamin D deficiency may increase predisposition to a number of pediatric orthopaedic conditions and the prevalence of vitamin D deficiency is increasing in children in developed countries. The aim of this study was to determine the epidemiology of vitamin D deficiency and insufficiency in children presenting to a regional pediatric orthopaedic service. We also examined the relationships between vitamin D status, social deprivation, and ethnicity. METHODS: Individuals of age 18 years and younger presenting to the regional pediatric orthopaedic service at Southampton, UK from 2008 to 2010 were investigated. Deprivation index scores were calculated from indices of deprivation. RESULTS: A total of 187 children (97 male, 90 female, mean age 7.1 y) underwent serum 25-hydroxyvitamin D level measurement. Of them 82% were white British and 11% were of Asian ethnicity. The calculation of the total depravation index for the whole cohort showed 34 patients (18%) were in quartile 1 (most deprived), 54 (29%) in quartile 2, 49 (26%) in quartile 3, and 50 (27%) in quartile 4 (least deprived). Sixty patients (32%) had vitamin D insufficiency with 25-(OH) levels <50 nmol/L and 15 patients (8%) had vitamin D deficiency. No relationship was identified between vitamin D level and social deprivation score. CONCLUSIONS: There is a need for awareness of the prevalence of vitamin D deficiency in the pediatric orthopaedic population presenting with bone pain and lower limb deformity before commencing "observation or orthopaedic surgical treatment." LEVEL OF EVIDENCE: 3.