Narrative Review: Peripheral Arterial Disease in Patients with Hyperuricemia and Gout.

PURPOSE OF REVIEW: To discuss what is currently known about the association and potential mechanistic interactions of hyperuricemia and gout with peripheral arterial disease (PAD). RECENT FINDINGS: Gout patients are at increased risk for coronary artery disease, but less is known about their risk for PAD. Studies suggest that the presence of gout and hyperuricemia are associated with PAD independent of known established risk factors. Moreover, higher SU was found to be associated with greater odds of having PAD and was independently associated with decreased absolute claudication distance. Urate's role in free radical formation, platelet aggregation, vascular smooth muscle proliferation, and impaired endothelial vasodilation may promote atherosclerotic progression. Studies suggest that patients with hyperuricemia or gout are at higher risk for developing PAD. Evidence is stronger for the relationship between elevated SU and PAD than for gout and PAD, but more data is needed. Whether elevated SU serves as a marker or cause of PAD remains to be investigated.

Treatment of Obesity in Mitigating Metabolic Risk.

Through diverse mechanisms, obesity contributes to worsened cardiometabolic health and increases rates of cardiovascular events. Effective treatment of obesity is necessary to reduce the associated burdens of diabetes mellitus, cardiovascular disease, and death. Despite increasing cardiovascular outcome data on obesity interventions, only a small fraction of the population with obesity are optimally treated. This is a primary impetus for this article in which we describe the typical weight loss, as well as the associated impact on both traditional and novel cardiovascular disease risk factors, provided by the 4 primary modalities for obtaining weight loss in obesity-dietary modification, increasing physical activity, pharmacotherapy, and surgery. We also attempt to highlight instances where changes in metabolic risk are relatively specific to particular interventions and appear at least somewhat independent of weight loss. Finally, we suggest important areas for further research to reduce and prevent adverse cardiovascular consequences due to obesity.

Mapping hospital data to characterize residents' educational experiences.

BACKGROUND: Experiential learning through patient care is fundamental to graduate medical education. Despite this, the actual content to which trainees are exposed in clinical practice is difficult to quantify and is poorly characterized. There remains an unmet need to define precisely how residents' patient care activities inform their educational experience.  METHODS: Using a recently-described crosswalk tool, we mapped principal ICD-10 discharge diagnosis codes to American Board of Internal Medicine (ABIM) content at four training hospitals of a single Internal Medicine (IM) Residency Program over one academic year to characterize and compare residents' clinical educational experiences. Frequencies of broad content categories and more specific condition categories were compared across sites to profile residents' aggregate inpatient clinical experiences and drive curricular change. RESULTS: There were 18,604 discharges from inpatient resident teams during the study period. The crosswalk captured > 95% of discharges at each site. Infectious Disease (ranging 17.4 to 39.5% of total discharges) and Cardiovascular Disease (15.8 to 38.2%) represented the most common content categories at each site. Several content areas (Allergy/Immunology, Dermatology, Obstetrics/Gynecology, Ophthalmology, Otolaryngology/Dental Medicine) were notably underrepresented (≤ 1% at each site). There were significant differences in the frequencies of conditions within most content categories, suggesting that residents experience distinct site-specific clinical content during their inpatient training. CONCLUSIONS: There were substantial differences in the clinical content experienced by our residents across hospital sites, prompting several important programmatic and curricular changes to enrich our residents' hospital-based educational experiences.

A Drosophila model of high sugar diet-induced cardiomyopathy.

Diets high in carbohydrates have long been linked to progressive heart dysfunction, yet the mechanisms by which chronic high sugar leads to heart failure remain poorly understood. Here we combine diet, genetics, and physiology to establish an adult Drosophila melanogaster model of chronic high sugar-induced heart disease. We demonstrate deterioration of heart function accompanied by fibrosis-like collagen accumulation, insulin signaling defects, and fat accumulation. The result was a shorter life span that was more severe in the presence of reduced insulin and P38 signaling. We provide evidence of a role for hexosamine flux, a metabolic pathway accessed by glucose. Increased hexosamine flux led to heart function defects and structural damage; conversely, cardiac-specific reduction of pathway activity prevented sugar-induced heart dysfunction. Our data establish Drosophila as a useful system for exploring specific aspects of diet-induced heart dysfunction and emphasize enzymes within the hexosamine biosynthetic pathway as candidate therapeutic targets.

A Drosophila functional evaluation of candidates from human genome-wide association studies of type 2 diabetes and related metabolic traits identifies tissue-specific roles for dHHEX.

BACKGROUND: Genome-wide association studies (GWAS) identify regions of the genome that are associated with particular traits, but do not typically identify specific causative genetic elements. For example, while a large number of single nucleotide polymorphisms associated with type 2 diabetes (T2D) and related traits have been identified by human GWAS, only a few genes have functional evidence to support or to rule out a role in cellular metabolism or dietary interactions. Here, we use a recently developed Drosophila model in which high-sucrose feeding induces phenotypes similar to T2D to assess orthologs of human GWAS-identified candidate genes for risk of T2D and related traits. RESULTS: Disrupting orthologs of certain T2D candidate genes (HHEX, THADA, PPARG, KCNJ11) led to sucrose-dependent toxicity. Tissue-specific knockdown of the HHEX ortholog dHHEX (CG7056) directed metabolic defects and enhanced lethality; for example, fat-body-specific loss of dHHEX led to increased hemolymph glucose and reduced insulin sensitivity. CONCLUSION: Candidate genes identified in human genetic studies of metabolic traits can be prioritized and functionally characterized using a simple Drosophila approach. To our knowledge, this is the first large-scale effort to study the functional interaction between GWAS-identified candidate genes and an environmental risk factor such as diet in a model organism system.

Mapping the Clinical Experience of a New York City Residency Program During the COVID-19 Pandemic.

The COVID-19 pandemic has dramatically disrupted the educational experience of medical trainees. However, a detailed characterization of exactly how trainees' clinical experiences have been affected is lacking. Here, we profile residents' inpatient clinical experiences across the four training hospitals of NYU's Internal Medicine Residency Program during the pandemic's first wave. We mined ICD-10 principal diagnosis codes attributed to residents from February 1, 2020, to May 31, 2020. We translated these codes into discrete medical content areas using a newly developed "crosswalk tool." Residents' clinical exposure was enriched in infectious diseases (ID) and cardiovascular disease content at baseline. During the pandemic's surge, ID became the dominant content area. Exposure to other content was dramatically reduced, with clinical diversity repopulating only toward the end of the study period. Such characterization can be leveraged to provide effective practice habits feedback, guide didactic and self-directed learning, and potentially predict competency-based outcomes for trainees in the COVID era.

Obesity Pharmacotherapy is Effective in the Veterans Affairs Patient Population: A Local and Virtual Cohort Study.

OBJECTIVE: Obesity is a major public health challenge, and the US military veteran population is disproportionately affected. Using deidentified records from a local weight management clinic and a national clinical data repository, obesity pharmacotherapy use and effectiveness for weight loss and obesity comorbidities in this vulnerable population were assessed. METHODS: During the initial year of the local clinic, 43 records with monthly follow-up of MOVE! lifestyle intervention augmented by obesity pharmacotherapy were found. Nationally, more than 2 million records of prescribed obesity pharmacotherapy compared with metformin as control were identified. Records with detailed documentation of weight trends from 1 year before to 1 year after the prescription date for further analysis were selected for review. RESULTS: The most commonly prescribed medications in the local clinic were metformin, liraglutide, and combination phentermine/topiramate. On average, weight loss of -4.0 ± 2.1 kg over the initial 6-month intervention was observed. In the national cohort, 577,491 records with an obesity or control metformin prescription and adequate weight documentation were identified. The most effective pharmacotherapy in the national cohort was phentermine/topiramate (-0.0931 ± 0.0198 kg/wk difference), followed by liraglutide, lorcaserin, and orlistat. CONCLUSIONS: Obesity pharmacotherapy is effective in achieving clinically meaningful weight loss in veterans as part of an integrated care approach.

PPARγ agonists delay age-associated metabolic disease and extend longevity.

Aging leads to a number of disorders caused by cellular senescence, tissue damage, and organ dysfunction. It has been reported that anti-inflammatory and insulin-sensitizing compounds delay, or reverse, the aging process and prevent metabolic disorders, neurodegenerative disease, and muscle atrophy, improving healthspan and extending lifespan. Here we investigated the effects of PPARγ agonists in preventing aging and increasing longevity, given their known properties in lowering inflammation and decreasing glycemia. Our molecular and physiological studies show that long-term treatment of mice at 14 months of age with low doses of the PPARγ ligand rosiglitazone (Rosi) improved glucose metabolism and mitochondrial functionality. These effects were associated with decreased inflammation and reduced tissue atrophy, improved cognitive function, and diminished anxiety- and depression-like conditions, without any adverse effects on cardiac and skeletal functionality. Furthermore, Rosi treatment of mice started when they were 14 months old was associated with lifespan extension. A retrospective analysis of the effects of the PPARγ agonist pioglitazone (Pio) on longevity showed decreased mortality in patients receiving Pio compared to those receiving a PPARγ-independent insulin secretagogue glimepiride. Taken together, these data suggest the possibility of using PPARγ agonists to promote healthy aging and extend lifespan.

Investigating complexity of protein-protein interactions in focal adhesions.

The formation of focal adhesions governs cell shape and function; however, there are few measurements of the binding kinetics of focal adhesion proteins in living cells. Here, we used the fluorescence recovery after photobleaching (FRAP) technique, combined with mathematical modeling and scaling analysis to quantify dissociation kinetics of focal adhesion proteins in capillary endothelial cells. Novel experimental protocols based on mathematical analysis were developed to discern the rate-limiting step during FRAP. Values for the dissociation rate constant k(OFF) ranged over an order of magnitude from 0.009+/-0.001/s for talin to 0.102+/-0.010/s for FAK, indicating that talin is bound more strongly than other proteins in focal adhesions. Comparisons with in vitro measurements reveal that multiple focal adhesion proteins form a network of bonds, rather than binding in a pair-wise manner in these anchoring structures in living cells.

Nanostructured magnetizable materials that switch cells between life and death.

Development of biochips containing living cells for biodetection, drug screening and tissue engineering applications is limited by a lack of reconfigurable material interfaces and actuators. Here we describe a new class of nanostructured magnetizable materials created with a femtosecond laser surface etching technique that function as multiplexed magnetic field gradient concentrators. When combined with magnetic microbeads coated with cell adhesion ligands, these materials form microarrays of 'virtual' adhesive islands that can support cell attachment, resist cell traction forces and maintain cell viability. A cell death (apoptosis) response can then be actuated on command by removing the applied magnetic field, thereby causing cell retraction, rounding and detachment. This simple technology may be used to create reconfigurable interfaces that allow users to selectively discard contaminated or exhausted cellular sensor elements, and to replace them with new living cellular components for continued operation in future biomedical microdevices and biodetectors.

Mechanical forces alter zyxin unbinding kinetics within focal adhesions of living cells.

The formation of focal adhesions that mediate alterations of cell shape and movement is controlled by a mechanochemical mechanism in which cytoskeletal tensional forces drive changes in molecular assembly; however, little is known about the molecular biophysical basis of this response. Here, we describe a method to measure the unbinding rate constant k(OFF) of individual GFP-labeled focal adhesion molecules in living cells by modifying the fluorescence recovery after photobleaching (FRAP) technique and combining it with mathematical modeling. Using this method, we show that decreasing cellular traction forces on focal adhesions by three different techniques--chemical inhibition of cytoskeletal tension generation, laser incision of an associated actin stress fiber, or use of compliant extracellular matrices--increases the k(OFF) of the focal adhesion protein zyxin. In contrast, the k(OFF) of another adhesion protein, vinculin, remains unchanged after tension dissipation. Mathematical models also demonstrate that these force-dependent increases in zyxin's k(OFF) that occur over seconds are sufficient to quantitatively predict large-scale focal adhesion disassembly that occurs physiologically over many minutes. These findings demonstrate that the molecular binding kinetics of some, but not all, focal adhesion proteins are sensitive to mechanical force, and suggest that force-dependent changes in this biophysical parameter may govern the supramolecular events that underlie focal adhesion remodeling in living cells.