Alcohol associated liver disease and bariatric surgery: Current perspectives and future directions

Bariatric surgery is a routinely performed procedure and is associated with a reduction in all-cause mortality in patients with obesity. However, bariatric surgery has also been linked to increased alcohol use with up to 30% of these patients developing alcohol use disorder (AUD). The mechanism of AUD after bariatric surgery is multifactorial and includes anatomic, metabolic, and neurohumoral changes associated with post-surgical anatomy. These patients are at increased risk of alcohol associated liver disease and, in some cases, require liver transplantation. In this article, we provide a scoping review of epidemiology, pathophysiology, and clinical outcomes of alcohol-related health conditions after bariatric surgery.

The progression of hepatorenal syndrome-acute kidney injury in acute alcohol-associated hepatitis: renal outcomes after liver transplant

Background

Hepatorenal syndrome-acute kidney injury (HRS-AKI) is a complication of advanced liver disease in patients with ascites and circulatory dysfunction. Little data remain on the relationship between HRS-AKI outcomes and different etiologies of liver disease post-liver transplant (LT).

Objectives

The primary aim was to evaluate the effect of HRS-AKI on renal outcomes in patients with acute alcohol-associated hepatitis (AAH) compared to chronic liver disease (CLD) after LT. The secondary aim was to evaluate the impact of acuity and chronicity of alcohol-associated liver disease in patients with HRS-AKI post-LT renal outcomes.

Design

A retrospective observational study of patients undergoing urgent inpatient liver transplant evaluation (LTE) for cirrhosis and AAH at single academic LT center between October 2017 and July 2021 was conducted.

Methods

Patients with HRS-AKI were selected based on indication for LTE: acute AAHHRS or CLDHRS. CLDHRS was categorized by disease etiology: cirrhosis due to alcohol (A-CLDHRS) versus cirrhosis from other causes (O-CLDHRS). CLD patients without HRS-AKI were labeled CLDno HRS.

Results

A total of 210 subjects underwent LTE; 25% were evaluated for AAH and 75% were evaluated for CLD. Hepatorenal syndrome was more common in subjects evaluated for AAH (37/47) than CLD (104/163) (78.7 versus 63.8%, p = 0.04). For the primary outcome, AAHHRS subjects required ⩾30 days post-LT renal replacement therapy (RRT) more often than subjects with CLDHRS (p = 0.02) and CLDno HRS (p < 0.01). There was no significant difference in other forms of long-term renal outcomes including kidney transplant referral and kidney transplant among cohorts. In subgroup analysis, 30-days post-LT RRT was more common in AAHHRS than in A-CLDHRS (p = 0.08). Logistic regression showed that AAHHRS conferred a 20× and 3.3× odds of requiring ⩾30 days post-LT RRT compared to CLDno HRS and CLDHRS, respectively. Postoperative complications were similar across cohorts, but had a significant effect on 30-day renal outcome post-LT.

Conclusions

Patients with AAH were more likely to develop HRS and require RRT pre- and post-LT at our center. The etiology of hepatic decompensation and postoperative complications affect renal recovery post-LT. The systemic inflammation of AAH in addition to conditions favoring renal hypoperfusion may contribute to the unfavorable outcomes of HRS-AKI after LT in this patient population.

Delayed referral for liver transplant evaluation worsens outcomes in chronic liver disease patients requiring inpatient transplant evaluation

BACKGROUND

Indications to refer patients with cirrhosis for liver transplant evaluation (LTE) include hepatic decompensation or a model for end stage liver disease (MELD-Na) score ≥ 15. Few studies have evaluated how delaying referral beyond these criteria affects patient outcomes.

AIM

To evaluate clinical characteristics of patients undergoing inpatient LTE and to assess the effects of delayed LTE on patient outcomes (death, transplantation).

METHODS

This is a single center retrospective cohort study assessing all patients undergoing inpatient LTE (n = 159) at a large quaternary care and liver transplant center between 10/23/2017-7/31/2021. Delayed referral was defined as having prior indication (decompensation, MELD-Na ≥ 15) for LTE without referral. Early referral was defined as referrals made within 3 mo of having an indication based on practice guidelines. Logistic regression and Cox Hazard Regression were used to evaluate the relationship between delayed referral and patient outcomes.

RESULTS

Many patients who require expedited inpatient LTE had delayed referrals. Misconceptions regarding transplant candidacy were a leading cause of delayed referral. Ultimately, delayed referrals negatively affected overall patient outcome and an independent predictor of both death and not receiving a transplant. Delayed referral was associated with a 2.5 hazard risk of death.

CONCLUSION

Beyond initial access to an liver transplant (LT) center, delaying LTE increases risk of death and reduces risk of LT in patients with chronic liver disease. There is substantial opportunity to increase the percentage of patients undergoing LTE when first clinically indicated. It is crucial for providers to remain informed about the latest guidelines on liver transplant candidacy and the transplant referral process.

Kidney disease in patients with chronic liver disease: Does sex matter?

Kidney disease in patients with liver disease is serious and increases mortality. Up to 50% of patients hospitalized experience an episode of acute kidney injury. In general, men with liver disease are thought to be at increased risk of kidney disease. However, this association should be considered with caution because most studies use creatinine-based inclusion criteria, which is negatively biased against women. In this review, we synthesize data on sex differences in kidney disease in patients with chronic liver disease in the clinical setting and discuss potential physiologic underpinnings.

Management of an iatrogenic duodenal perforation with a helical tack system in a patient with pancreatic cancer complicated by gastric outlet obstruction

Video 1Closure of an iatrogenic perforation with helical tack system and subsequent EUS-guided choledochoduodenostomy.

COVID-19 associated liver injury: A general review with special consideration of pregnancy and obstetric outcomes

Liver injury is an increasingly recognized extra-pulmonary manifestation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Coronavirus disease 2019 (COVID-19) associated liver injury (COVALI) is a clinical syndrome encompassing all patients with biochemical liver injury identified in the setting of SARS-CoV-2 infection. Despite profound clinical implications, its pathophysiology is poorly understood. Unfortunately, most information on COVALI is derived from the general population and may not be applicable to individuals under-represented in research, including pregnant individuals. This manuscript reviews: Clinical features of COVALI, leading theories of COVALI, and existing literature on COVALI during pregnancy, a topic not widely explored in the literature. Ultimately, we synthesized data from the general and perinatal populations that demonstrates COVALI to be a hepatocellular transaminitis that is likely induced by systemic inflammation and that is strongly associated with disease severity and poorer clinical outcome, and offered perspective on approaching transaminitis in the potentially COVID-19 positive patient in the obstetric setting.

Study of Crystal Formation and Nitric Oxide (NO) Release Mechanism from S-Nitroso-N-acetylpenicillamine (SNAP)-Doped CarboSil Polymer Composites for Potential Antimicrobial Applications

Stable and long-term nitric oxide (NO) releasing polymeric materials have many potential biomedical applications. Herein, we report the real-time observation of the crystallization process of the NO donor, S-nitroso-N-acetylpenicillamine (SNAP), within a thermoplastic silicone-polycarbonate-urethane biomedical polymer, CarboSil 20 80A. It is demonstrated that the NO release rate from this composite material is directly correlated with the surface area that the CarboSil polymer film is exposed to when in contact with aqueous solution. The decomposition of SNAP in solution (e.g. PBS, ethanol, THF, etc.) is a pseudo-first-order reaction proportional to the SNAP concentration. Further, catheters fabricated with this novel NO releasing composite material are shown to exhibit significant effects on preventing biofilm formation on catheter surface by Pseudomonas aeruginosa and Proteus mirabilis grown in CDC bioreactor over 14 days, with a 2 and 3 log-unit reduction in number of live bacteria on their surfaces, respectively. Therefore, the SNAP-CarboSil composite is a promising new material to develop antimicrobial catheters, as well as other biomedical devices.

Reduction of Thrombosis and Bacterial Infection via Controlled Nitric Oxide (NO) Release from S-Nitroso-N-acetylpenicillamine (SNAP) Impregnated CarboSil Intravascular Catheters

Nitric oxide (NO) has many important physiological functions, including its ability to inhibit platelet activation and serve as potent antimicrobial agent. The multiple roles of NO in vivo have led to great interest in the development of biomaterials that can deliver NO for specific biomedical applications. Herein, we report a simple solvent impregnation technique to incorporate a nontoxic NO donor, S-nitroso-N-acetylpenicillamine (SNAP), into a more biocompatible biomedical grade polymer, CarboSil 20 80A. The resulting polymer-crystal composite material yields a very stable, long-term NO release biomaterial. The SNAP impregnation process is carefully characterized and optimized, and it is shown that SNAP crystal formation occurs in the bulk of the polymer after solvent evaporation. LC-MS results demonstrate that more than 70% of NO release from this new composite material originates from the SNAP embedded CarboSil phase, and not from the SNAP species leaching out into the soaking solution. Catheters prepared with CarboSil and then impregnated with 15 wt % SNAP provide a controlled NO release over a 14 d period at physiologically relevant fluxes and are shown to significantly reduce long-term (14 day) bacterial biofilm formation against Staphylococcus epidermidis and Pseudonomas aeruginosa in a CDC bioreactor model. After 7 h of catheter implantation in the jugular veins of rabbit, the SNAP CarboSil catheters exhibit a 96% reduction in thrombus area (0.03 ± 0.01 cm2/catheter) compared to the controls (0.84 ± 0.19 cm2/catheter) (n = 3). These results suggest that SNAP impregnated CarboSil can become an attractive new biomaterial for use in preparing intravascular catheters and other implanted medical devices.

CD82 Is a Marker for Prospective Isolation of Human Muscle Satellite Cells and Is Linked to Muscular Dystrophies

Cell-surface markers for prospective isolation of stem cells from human skeletal muscle have been difficult to identify. Such markers would be powerful tools for studying satellite cell function during homeostasis and in pathogenesis of diseases such as muscular dystrophies. In this study, we show that the tetraspanin KAI/CD82 is an excellent marker for prospectively isolating stem cells from human fetal and adult skeletal muscle. Human CD82⁺ muscle cells robustly engraft into a mouse model of muscular dystrophy. shRNA knockdown of CD82 in myogenic cells reduces myoblast proliferation, suggesting it is functionally involved in muscle homeostasis. CD82 physically interacts with alpha7beta1 integrin (α7β1-ITG) and with α-sarcoglycan, a member of the Dystrophin-Associated Glycoprotein Complex (DAPC), both of which have been linked to muscular dystrophies. Consistently, CD82 expression is decreased in Duchenne muscular dystrophy patients. Together, these findings suggest that CD82 function may be important for muscle stem cell function in muscular disorders.

Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

P1 Impact of antioxidant-enriched nutrient bar supplementation on the serum antioxidant markers and physical fitness components of track and field athletes

Lalitha Ramaswamy, Supriya Velraja

P2 The effects of phosphatidic acid supplementation on fitness levels in resistance trained women

Guillermo Escalante, Phil Harvey, Michelle Alencar, Bryan Haddock

P3 The effects of phosphatidic acid supplementation on cardiovascular risk factors in resistance trained men

Phil Harvey, Guillermo Escalante, Michelle Alencar, Bryan Haddock

P4 The efficacy of sodium bicarbonate supplementation on physical capacity and selected biochemical markers in elite wrestlers

Krzysztof Durkalec-Michalski, Jan Jeszka, Bogna Zawieja, Tomasz Podgórski

P5 Effects of different nutritional strategies in hydration and physical performance in healthy well-trained males

Ana Paula Trussardi Fayh, Alexandre Hideki Okano, Amanda Maria de Jesus Ferreira

P6 Reduction of plasma creatine concentrations as an indicator of improved bioavailability

Ralf Jäger, Martin Purpura, Roger C Harris

P7 Effect of three different breakfast meals on energy intake and nutritional status in college-age women

Molly M. Krause, Kiley A. Lavanger, Nina O. Allen, Allison E. Lieb, Katie A. Mullen, Joan M. Eckerson

P8 Accuracy of the ASA24® Dietary Recall system for assessing actual dietary intake in normal weight college-age women.

Kiley A. Lavanger, Molly M. Krause, Nina O. Allen, Allison E. Lieb, Katie A. Mullen, Joan M. Eckerson

P9 β-aminoisobutyric acid does not regulate exercise induced UCP-3 expression in skeletal muscle

Elisa Morales, Jeffrey Forsse, Thomas Andre, Sarah McKinley, Paul Hwang, Grant Tinsley, Mike Spillane, Peter Grandjean, Darryn Willoughby

P10 The ability of collegiate football athletes to adhere to sport-specific nutritional recommendations

A. Jagim, G. Wright, J. Kisiolek, M. Meinking, J. Ochsenwald, M. Andre, M.T. Jones, J. M. Oliver

P11 A single session of low-volume high intensity interval exercise improves appetite regulation in overweight men

Victor Araújo Ferreira, Daniel Costa de Souza, Victor Oliveira Albuquerque dos Santos, Rodrigo Alberto Vieira Browne, Eduardo Caldas Costa, Ana Paula Trussardi Fayh

P12 Acute effects of oral peppermint oil ingestion on exercise performance in moderately-active college students

Suresh T. Mathews, Haley D. Bishop, Clara R. Bowen, Yishan Liang, Emily A. West, Rebecca R. Rogers, Mallory R. Marshall, John K. Petrella

P13 Associations in body fat and liver triglyceride content with serum health markers in sedentary and exercised rats fed a ketogenic diet, Western diet or standard chow over a 6-week period

A. Maleah Holland, Wesley C. Kephart, Petey W. Mumford, C. Brooks Mobley, Ryan P. Lowery, Jacob M. Wilson, Michael D. Roberts

P14 Physiological changes following competition in male and female physique athletes: A pilot study

Eric T. Trexler, Katie R. Hirsch, Bill I. Campbell, Meredith G. Mock, Abbie E. Smith-Ryan

P15 Relationship between cognition and hydration status in college students at a large Southwestern university

Kate Zemek, Carol Johnston

P16 Whey protein-derived exosomes increase protein synthesis in C2C12 myotubes

C. Brooks Mobley, Petey W. Mumford, David D. Pascoe, Christopher M. Lockwood, Michael E. Miller, Michael D. Roberts

P17 The effect of three different energy drinks on 1.5-mile running performance, oxygen consumption, and perceived exertion

Gabriel J. Sanders, Willard Peveler, Brooke Warning, Corey A. Peacock

P18 The Ketogenic diet improves rotarod performance in young and older rats

Wesley C. Kephart, Petey W. Mumford, Ryan P. Lowery, Michael D. Roberts, Jacob M. Wilson

P19 Absorption of bonded arginine silicate compared to individual arginine and silicon components

David Sandler, Sara Perez Ojalvo, James Komorowski

P20 Effects of a high (2.4 g/kg) vs. low/moderate (1.2 g/kg) protein intake on body composition in aspiring female physique athletes engaging in an 8-week resistance training program

Bill I. Campbell, Danielle Aguilar, Andres Vargas, Laurin Conlin, Amey Sanders, Paola Fink-Irizarry, Layne Norton, Ross Perry, Ryley McCallum, Matthew R. Wynn, Jack Lenton

P21 Effects of a high (2.4 g/kg) vs. low/moderate (1.2 g/kg) protein intake on maximal strength in aspiring female physique athletes engaging in an 8-week resistance training program

Bill I. Campbell, Chris Gai, Seth Donelson, Shiva Best, Daniel Bove, Kaylee Couvillion, Jeff Dolan, Dante Xing, Kyshia Chernesky, Michael Pawela, Andres D. Toledo, Rachel Jimenez

P22 Monitoring of female collegiate athletes over a competitive season reveals changes in nutritional biomarkers

M. Rabideau, A. Walker, J. Pellegrino, M. Hofacker, B. McFadden, S. Conway, C. Ordway, D. Sanders, R. Monaco, M. S. Fragala, S. M. Arent

P23 Comparison of prediction equations to indirect calorimetry in men and women athletes

Jason D. Stone, Andreas Kreutzer, Jonathan M. Oliver, Jacob Kisiolek, Andrew R. Jagim

P24 Regional variations in sweat-based electrolyte loss and changes in plasma electrolyte content in Division I female athletes over the course of a competitive season

M. Hofacker, A. Walker, J. Pellegrino, M. Rabideau, B. McFadden, S. Conway, D. Sanders, C. Ordway, R. Monaco, M. S. Fragala, S. M. Arent

P25 In-season changes in plasma amino acid levels in Division I NCAA female athletes

Ozlem Tok, Joseph K. Pellegrino, Alan J. Walker, David J. Sanders, Bridget A. McFadden, Meaghan M. Rabideau, Sean P. Conway, Chris E. Ordway, Marissa Bello, Morgan L. Hofacker, Nick S. Mackowski, Anthony J. Poyssick, Eddie Capone, Robert M. Monaco, Maren S. Fragala, Shawn M. Arent

P26 Effects of a ketogenic diet with exercise on serum markers of bone metabolism, IGF-1 and femoral bone mass in rats

Petey W. Mumford, A. Maleah Holland, Wesley C. Kephart, Ryan P. Lowery, C. Brooks Mobley, Romil K. Patel, Annie Newton, Darren T. Beck, Michael D. Roberts, Jacob M. Wilson, Kaelin C. Young

P27 Casein supplementation in trained men and women: morning versus evening

Tobin Silver, Anya Ellerbroek, Richard Buehn, Leo Vargas, Armando Tamayo, Corey Peacock, Jose Antonio

P28 A high protein diet has no harmful effects: a one-year crossover study in resistance-trained males

Anya Ellerbroek, Tobin Silver, Richard Buehn, Leo Vargas, Armando Tamayo, Corey Peacock, Jose Antonio

P29 SUP (Stand-up Paddling) athletes: nutritional intake and body composition

Adam Pollock, Anya Ellerbroek, Tobin Silver, Corey Peacock, Jose Antonio

P30 The effects of 8 weeks of colostrum and bio-active peptide supplementation on body composition in recreational male weight lifters

A. Kreutzer, P. Zavala, S. Fleming, M. Jones, J. M. Oliver, A. Jagim

P31 Effects of a Popular Women’s Thermogenic Supplement During an Energy-Restricted High Protein Diet on Changes in Body Composition and Clinical Safety Markers

Cody T. Haun, Petey W. Mumford, Parker N. Hyde, Ciaran M. Fairman, Wesley C. Kephart, Darren T. Beck, Jordan R. Moon, Michael D. Roberts, Kristina L. Kendall, Kaelin C. Young

P32 Three days of caffeine consumption following caffeine withdrawal yields small strength increase in knee flexors

Geoffrey M Hudson, Tara Hannings, Kyle Sprow, Loretta DiPietro

P33 Comparison of cellular nitric oxide production from various sports nutrition ingredients

Doug Kalman, Sara Perez Ojalvo, James Komorowski

P34 The effects of 8 weeks of bio-active peptide supplementation on training adaptations in recreational male weight lifters

P. Zavala, S. Fleming, M. Jones, J. Oliver, A. Jagim

P35 Effects of MusclePharm Assault Black^TM on lower extremity spinal excitability and postactivation potentiation: A pilot study

Brian Wallace, Haley Bergstrom, Kelly Wallace

P36 Effects of four weeks of Ketogenic Diet alone and combined with High intensity Interval Training or Continuous-Moderate intensity on body composition, lipid profile and physical performance on healthy males

Matias Monsalves-Alvarez, Sebastian Oyharçabal, Victoria Espinoza

P37 Effect of branched-chain amino acid supplementation on creatine kinase, muscular performance, and perceived muscle soreness following acute eccentric exercise

Trisha A. VanDusseldorp, Kurt A. Escobar, Kelly E. Johnson, Nathan Cole, Terence Moriarty, Matthew Stratton, Marvin R. Endito, Christine M. Mermier, Chad M. Kerksick

P38 Effects of endurance training on markers of ribosome biogenesis in rodents fed a high fat diet

Matthew A. Romero, C. Brooks Mobley, Melissa Linden, Grace Margaret-Eleanor Meers, R. Scott Rector, Michael D. Roberts

P39 The effects of acute citrulline-malate on lower-body isokinetic performance in recreationally active individuals

Joshua L Gills, Hocheng Lu, Kimberly Parker, Chris Dobbins, Joshua N Guillory, Braden Romer, David Szymanski, Jordan Glenn

P40 The effect pre-ingested L-isoleucine and L-leucine on blood glucose responses and glycemic hormones in healthy inactive adults: Preliminary data.

Daniel E. Newmire, Eric Rivas, Sarah E. Deemer, Robert Wildman, Victor Ben-Ezra

P41 Does protein and source impact substrate oxidation and energy expenditure during and after moderate intensity treadmill exercise?

C Kerksick, B Gieske, R Stecker, C Smith, K Witherbee

P42 Effects of a pre-workout supplement on peak power and power maintenance during lower and upper body testing

Michael T. Lane, M. Travis Byrd, Zachary Bell, Emily Frith, Lauren M.C. Lane

P43 Effects of a pre-workout supplement on peak power production during lower and upper body testing in college-age females

Michael T. Lane, M. Travis Byrd, Zachary Bell, Emily Frith, Lauren M.C. Lane

P44 A comparison of whey versus casein protein supplementation on resting metabolic rate and body composition: a pilot study

Corey A. Peacock, Tobin A. Silver, Megan Colas, Mauricio Mena, Winter Rodriguez, Gabriel J. Sanders, Jose Antonio

P45 A novel mixed-tocotrienol intervention enhances recovery after eccentric exercise: preliminary findings

Andrea Vansickle, Brittany DiFiore, Stephanie Stepp, Grant Slack, Bridget Smith, Kayla Ruffner, Ronald Mendel, Lonnie Lowery

P46 The effects of post-exercise ingestion of a high molecular weight glucose on cycle performance in female cyclists

Katie R. Hirsch, Meredith G. Mock, Malia M.N. Blue, Eric T. Trexler, Erica J. Roelofs, Abbie E. Smith-Ryan

P47 Inclusive vs. exclusive dieting and the effects on body composition in resistance trained individuals

Laurin Conlin, Danielle Aguilar, Bill I. Campbell, Layne Norton, Katie Coles, Eric T. Trexler, Nic Martinez

P48 A whey protein hydrolysate may positively augment resting metabolism compared to intact whey protein

Jordan M. Joy, Roxanne M. Vogel, Thomas H. Hoover, K. Shane Broughton

P49 Seven days of high and low dose creatine nitrate supplementation I: hepatorenal, glucose and muscle enzyme function

R Dalton, R Sowinski, T Grubic, PB Collins, A Colletta, A Reyes, B Sanchez, M Kozehchain, YP Jung, C Rasmussen, P Murano, CP Earnest, M Greenwood, RB Kreider

P50 Seven days of high and low dose creatine nitrate supplementation II: performance

T Grubic, R Dalton, R Sowinski, PB Collins, A Colletta, A Reyes, B Sanchez, M Kozehchain, YP Jung, C Rasmussen, P Murano, CP Earnest, M Greenwood, RB Kreider

P51 Seven days of high and low dose creatine nitrate supplementation III: hemodynamics

R Sowinski, R Dalton, T Grubic, PB Collins, A Colletta, A Reyes, B Sanchez, M Kozehchain, YP Jung, C Rasmussen, P Murano, CP Earnest, M Greenwood, RB Kreider

P52 The efficacy of a β-hydroxy-β-methylbutyrate supplementation on physical capacity, body composition and biochemical markers in highly-trained combat sports athletes

Krzysztof Durkalec-Michalski, Jan Jeszka, Tomasz Podgórski

P53 Does protein and source impact substrate oxidation and energy expenditure during and after moderate intensity treadmill exercise?

C Kerksick, B Gieske, R Stecker, C Smith, K Witherbee

P54 Effects of 30 days of Cleanse™ supplementation on measure of body composition, waist circumference, and markers of gastrointestinal distress in females

Stacie Urbina, Emily Santos, Katelyn Villa, Alyssa Olivencia, Haley Bennett, Marissa Lara, Cliffa Foster, Colin Wilborn, Lem Taylor

P55 The effects of moderate- versus high-load training on body composition, muscle growth, and performance in college aged females

Jason M Cholewa, Amy Hewins, Samantha Gallo, Ashley Micensky, Christian De Angelis, Christopher Carney, Bill Campbell, Laurin Conlin, Layne Norton, Fabricio Rossi

P56 Effect of a multi-ingredient preworkout supplement on cognitive function and perceptions of readiness to perform

MS Koozehchian, PB Collins, R Sowinski, T Grubic, R Dalton, A O’Connor, SY Shin, Y Peter Jung, BK Sanchez, A Coletta, M Cho, A Reyes, C Rasmussen, CP Earnest, PS Murano, M Greenwood, RB Kreider

Efficient Eradication of Mature Pseudomonas aeruginosa Biofilm via Controlled Delivery of Nitric Oxide Combined with Antimicrobial Peptide and Antibiotics

Fast eradication of mature biofilms is the ‘holy grail’ in the clinical management of device-related infections. Endogenous nitric oxide (NO) produced by macrophages plays an important role in host defense against intracellular pathogens, and NO is a promising agent in preventing biofilms formation in vitro. However, the rate of delivery of NO by various NO donors (e.g., diazeniumdiolates, S-nitrosothiols, etc.) is difficult to control, which hinders fundamental studies aimed at understanding the role of NO in biofilm control. In this study, by using a novel precisely controlled electrochemical NO releasing catheter device, we examine the effect of physiological levels of NO on eradicating mature Pseudomonas aeruginosa biofilm (7 days), as well as the potential application of the combination of NO with antimicrobial agents. It is shown that physiological levels of NO exhibit mixed effects of killing bacteria and dispersing ambient biofilm. The overall biofilm-eradicating effect of NO is quite efficient in a dose-dependent manner over a 3 h period of NO treatment. Moreover, NO also greatly enhances the efficacy of antimicrobial agents, including human beta-defensin 2 (BD-2) and several antibiotics, in eradicating biofilm and its detached cells, which otherwise exhibited high recalcitrance to these antimicrobial agents. The electrochemical NO release technology offers a powerful tool in evaluating the role of NO in biofilm control as well as a promising approach when combined with antimicrobial agents to treat biofilm-associated infections in hospital settings, especially infections resulting from intravascular catheters.

Origin of Long-Term Storage Stability and Nitric Oxide Release Behavior of CarboSil Polymer Doped with S-Nitroso-N-acetyl-D-penicillamine

The prolonged and localized delivery of nitric oxide (NO), a potent antithrombotic and antimicrobial agent, has many potential biomedical applications. In this work, the origin of the long-term storage stability and sustained NO release mechanism of S-nitroso-N-acetyl-D-penicillamine (SNAP)-doped CarboSil 20 80A polymer, a biomedical thermoplastic silicone-polycarbonate-urethane, is explored. Long-term (22 days) localized NO release is achieved by utilizing a cross-linked silicone rubber as topcoats, which can greatly reduce the amount of SNAP, NAP, and NAP disulfide leaching from the SNAP-doped CarboSil films, as measured by LC-MS. Raman spectroscopy and powder X-ray diffraction characterization of SNAP-doped CarboSil films demonstrate that a polymer-crystal composite is formed during the solvent evaporation process when SNAP exceeds its solubility in CarboSil (ca. 3.4-4.0 wt %). Further, when exceeding this solubility threshold, SNAP exists in an orthorhombic crystal form within the bulk of the polymer. The proposed mechanism of sustained NO release in SNAP-doped CarboSil is that the solubilized SNAP in the polymer matrix decomposes and releases NO, primarily in the water-rich regions near the polymer/solution interface, and the dissolved SNAP in the bulk polymeric phase becomes unsaturated, resulting in the dissolution of crystalline SNAP within the bulk of the polymer. This is a very slow process that ultimately leads to NO release at the physiological flux levels for >3 weeks. The increased stability of SNAP within CarboSil is attributed to the intermolecular hydrogen bonds between the SNAP molecules that crystallize. This crystallization also plays a key role in maintaining RSNO stability within the CarboSil polymer for >8 months at 37 °C (88.5% remains). Further, intravascular catheters fabricated with this new material are demonstrated to significantly decrease the formation of Staphylococcus aureus biofilm (a leading cause of nosocomial bloodstream infections) (in vitro) over a 7 day period, with 5 log units reduction of viable cell count on catheter surfaces. It is also shown that the NO release catheters can greatly reduce thrombus formation on the catheter surfaces during 7 h implantation in rabbit veins, when compared to the control catheters fabricated without SNAP. These results suggest that the SNAP-doped CarboSil system is a very attractive new composite material for creating long-term NO release medical devices with increased stability and biocompatibility.

Shared epitope-antagonistic ligands: a new therapeutic strategy in mice with erosive arthritis

OBJECTIVE

The mechanisms underlying bone damage in rheumatoid arthritis (RA) are incompletely understood. We recently identified the shared epitope (SE), an HLA-DRB1-coded 5-amino acid sequence motif carried by the majority of RA patients as a signal transduction ligand that interacts with cell surface calreticulin and accelerates osteoclast (OC)-mediated bone damage in collagen-induced arthritis (CIA). Given the role of the SE/calreticulin pathway in arthritis-associated bone damage, we sought to determine the therapeutic targetability of calreticulin.

METHODS

A library of backbone-cyclized peptidomimetic compounds, all carrying an identical core DKCLA sequence, was synthesized. The ability of these compounds to inhibit SE-activated signaling and OC differentiation was tested in vitro. The effect on disease severity and OC-mediated bone damage was studied by weekly intraperitoneal administration of the compounds to DBA/1 mice with CIA.

RESULTS

Two members of the peptidomimetics library were found to have SE-antagonistic effects and antiosteoclast differentiation effects at picomolar concentrations in vitro. The lead mimetic compound, designated HS(4-4)c Trp, potently ameliorated arthritis and bone damage in vivo when administered in picogram doses to mice with CIA. Another mimetic analog, designated HS(3-4)c Trp, was found to lack activity, both in vitro and in vivo. The differential activity of the 2 analogs depended on minor differences in their respective ring sizes and correlated with distinctive geometry when computationally docked to the SE binding site on calreticulin.

CONCLUSION

These findings identify calreticulin as a novel therapeutic target in erosive arthritis and provide sound rationale and early structure/activity relationships for future drug design.

Thromboresistant/anti-biofilm catheters via electrochemically modulated nitric oxide release

Inexpensive nitric oxide (NO) release strategies to prevent thrombosis and bacterial infections are desirable for implantable medical devices. Herein, we demonstrate the utility of electrochemically modulated NO release from a catheter model using an inner copper wire working electrode and an inorganic nitrite salt solution reservoir. These catheters generate NO surface fluxes of >1.0 × 10(-10)mol min(-1) cm(-2) for more than 60 h. Catheters with an NO flux of 1.1 × 10(-10)mol min(-1) cm(-2) are shown to significantly reduce surface thrombus formation when implanted in rabbit veins for 7h. Further, the ability of these catheters to exhibit anti-biofilm properties against bacterial species commonly causing bloodstream and urinary catheter infections is examined. Catheters releasing NO continuously during the 2d growth of Staphylococcus aureus exhibit a 6 log-unit reduction in viable surface bacteria. We also demonstrate that catheters generating NO for only 3h at a flux of 1.0 × 10(-10)mol min(-1) cm(-2) lower the live bacterial counts of both 2d and 4d pre-formed Escherichia coli biofilms by >99.9%. Overall, the new electrochemical NO-release devices could provide a cost-effective strategy to greatly enhance the biocompatibility and antimicrobial properties of intravascular and urinary catheters, as well as other implantable medical devices.

S-Nitroso-N-acetylpenicillamine (SNAP) Impregnated Silicone Foley Catheters: A Potential Biomaterial/Device To Prevent Catheter-Associated Urinary Tract Infections

Urinary Foley catheters are utilized for management of hospitalized patients and are associated with high rates of urinary tract infections (UTIs). Nitric oxide (NO) potently inhibits microbial biofilm formation, which is the primary cause of catheter associated UTIs (CAUTIs). Herein, commercial silicone Foley catheters are impregnated via a solvent swelling method with S-nitroso-N-acetyl-D-penicillamine (SNAP), a synthetic NO donor that exhibits long-term NO release and stability when incorporated into low water-uptake polymers. The proposed catheters generate NO surface-fluxes >0.7 × 10^–10 mol min^–1 cm^–2 for over one month under physiological conditions, with minimal SNAP leaching. These biomedical devices are demonstrated to significantly decrease formation of biofilm on the surface of the catheter tubings over 3, 7, and 14 day periods by microbial species (Staphylococcus epidermidis and Proteus mirabilis) commonly causing CAUTIs. Toxicity assessment demonstrates that the SNAP-impregnated catheters are fully biocompatible, as extracts of the catheter tubings score 0 on a 3-point grading scale using an accepted mouse fibroblast cell-line toxicity model. Consequently, SNAP-impregnated silicone Foley catheters can likely provide an efficient strategy to greatly reduce the occurrence of nosocomial CAUTIs.

Fibrosis progression in HCV carriers with mild hepatitis who possess the high-repetition variant of the DRD4 gene, a genetic marker for binge-drinking and risk-seeking behavior: a longitudinal study

BACKGROUND

Alcohol is a major determinant of the outcome of chronic hepatitis C virus (HCV) infection, but self-reported drinking habits lack reliability. We hypothesized that carriage of high-repetition variants (HRV) of the variable number of tandem repeats (VNTR) in exon III of the dopamine receptor D4 gene, linked to binge-drinking and risk-seeking behavior, might be a proxy measure of alcohol consumption, and aimed to verify whether it may affect histologic outcome.

METHODS

A cohort of HCV patients with normal or near-normal aminotransferases (N = 128) underwent a liver biopsy as part of diagnostic work-up. None admitted to exceed low-risk alcohol consumption; most (90/128, 70%) described themselves as teetotalers. They received advice on abstaining from alcohol, but not antiviral treatment. After a median follow-up period of 10 years, all underwent a second liver biopsy. HRV allele frequencies were compared with those of a group of healthy blood donors (N = 128) and related to liver histology.

RESULTS

HRV allele frequencies were 0.19 in patients and 0.16 in controls (p = 0.182). In the subgroup of patients who admittedly had consumed alcohol, 20/38 (53%) carried HRV, in comparison with 27/90 patients (30%) who had denied to consume alcohol (p = 0.026 by Fisher's exact test). Carriage of HRV was associated with higher histologic grade (p = 0.002) and stage (p = 0.009) at the final biopsy. At multivariate analysis, among a set of variables also including viral genotype, viral load, body mass index, gender, and history of alcohol consumption, only age (OR = 1.06, 95% CI 1.02 to 1.11) and HRV (OR = 3.13, 95% CI 1.28 to 7.68) were independent predictors of significant fibrosis at the end of follow-up.

CONCLUSIONS

The link between HRV carriage and histologic outcome in a subgroup of HCV patients at low risk of progression underlines the need for intense scrutiny of alcohol habits in hepatitis C.

An HLA-DRB1-coded signal transduction ligand facilitates inflammatory arthritis: a new mechanism of autoimmunity

Particular alleles of HLA contribute to disease susceptibility and severity in many autoimmune conditions, but the mechanisms underlying these associations are often unknown. In this study, we demonstrate that the shared epitope (SE), an HLA-DRB1-coded sequence motif that is the single most significant genetic risk factor for erosive rheumatoid arthritis, acts as a signal transduction ligand that potently activates osteoclastogenesis, both in vitro and in vivo. The SE enhanced the production of several pro-osteoclastogenic factors and facilitated osteoclast (OC) differentiation in mouse and human cells in vitro. Transgenic mice expressing a human HLA-DRB1 allele that code the SE motif demonstrated markedly higher propensity for osteoclastogenesis and enhanced bone degradation capacity ex vivo. In addition, the SE enhanced the differentiation of Th17 cells expressing the receptor activator for NF-κB ligand. When the two agents were combined, IL-17 and the SE enhanced OC differentiation synergistically. When administered in vivo to mice with collagen-induced arthritis, the SE ligand significantly increased arthritis severity, synovial tissue OC abundance, and bone erosion. Thus, the SE contributes to arthritis severity by activating an OC-mediated bone-destructive pathway. These findings suggest that besides determining the target specificity of autoimmune responses, HLA molecules may influence disease outcomes by shaping the pathogenic consequences of such responses.

Breast Cancer: A Revolutionary Concept

In this paper we trace the evolution of paradigms concerning the nature of breast cancer and their therapeutic consequences. There is no doubt that the conceptual revolution of about 20 years ago has led to modest gains in survival following the use of adjuvant systemic therapy and the quality of survival by demonstrating the safety of conservative surgical regimens. At the same time, there seems to be a plateau in progress. The results of adjuvant systemic therapy are not as good as anticipated and there are a number of other inconsistencies within the conventional model of biological predeterminism that remain to be explained. We offer up an alternative paradigm that suggests that not all metastases are due to cellular dissemination with late onset local and distant recurrence resulting from a transfection phenomenon, whereby subcellular particles shed by the primary cancer cell are taken up by wandering cells of the monocyte macrophage system and transported to distant sites where the local mesenchymal cells are transfected with the genetic information that activates components of the genome to instruct these plastic cells to express the phenotypic picture of a dedifferentiated breast duct epithelial cell. Such a conceptual revolution will open up the way for a new program of research and the development of therapies based on anti-viral rather than cytotoxic drugs.

Apolipoproteins C-II and C-III in peripheral arterial disease

Apolipoprotein (apo) C-II and apo C-III serum concentrations were investigated in 119 normotriglyceridemic male subjects with peripheral arterial disease (PAD) or coronary heart disease (CHD) or without clinical manifestations of atherosclerotic disease. All subjects included in the study had similar blood levels of total cholesterol (< 400 mg/dL). High-density lipoproteins cholesterol (HDL-C) subfractions and apo A-I serum levels were significantly lower in CHD patients, as were apo A-I/apo B and HDL-cholesterol/total cholesterol ratios. Apo C-II and apo C-III showed similar serum concentrations in all three groups of subjects, but apo C-II/apo C-III ratio was significantly lower in PAD patients as compared with that in CHD patients and control subjects. This study confirms that PAD may be associated with a particular lipoprotein derangement that primarily involves very low-density lipoprotein catabolism.

Prospects for the chemoprevention of breast cancer

Breast cancer is by far the most common type of cancer in women accounting for 20% of all new cases. It is estimated that 1 in 12 women will develop breast cancer at some time in their life. Each year in the UK, 24,500 women are newly diagnosed with breast cancer and 15,000 women die from it. The incidence rates rise from less than 10 per 100,000 women aged under 30 years to 300 per 100,000 in women aged over 85 years. The seriousness of the problem is emphasized by the fact that for women aged 35-54 years, breast cancer is the commonest single cause of all death. Both the incidence and the mortality have slightly increased in recent years, although mainly in the older age groups. There has been a slight decrease in the mortality rates for women aged 15-44 years over the last 35 years, but in all the older age groups there have been increases.

Regulation of transforming growth factor-beta subtypes by members of the steroid hormone superfamily

Transforming growth factor-beta s (TGF-beta s) are potent regulators of cell growth and differentiation. Expression of the closely related TGF-beta subtypes in vivo is differentially regulated both temporally and spatially. Members of the steroid hormone superfamily may play an important role in this gene- and tissue-specific regulation. We have shown that anti-estrogens induce the production of TGF-beta 1 in mammary carcinoma cells and fetal fibroblasts, whereas retinoic acid specifically induces TGF-beta 2 in primary epidermal keratinocytes. The induction of TGF-beta 2 by retinoids is accompanied by an increase in TGF-beta 2 mRNAs, but little change in transcription rates, suggesting an effect of retinoids on message stability or processing. In contrast, TGF-beta 1 mRNA levels are unchanged by anti-estrogen treatment, suggesting these compounds may regulate the translatability of the TGF-beta 1 message or some post-translational processing event. We have identified a stable stem-loop structure in the 5' untranslated region (UTR) of the TGF-beta 1 mRNA that inhibits translation of a heterologous reporter gene, and we are investigating the possibility that anti-estrogens may regulate the activity of this element, and hence the translatability of the TGF-beta 1 message. A significant fraction (25-90%) of the TGF-beta induced by retinoids and anti-estrogens is in the biologically active rather than the latent form. We have shown that active TGF-beta has a much shorter in vivo half-life than latent TGF-beta, suggesting that the TGF-beta induced by retinoids and steroids may act locally at the site of production. Since many tumor cells retain sensitivity to the growth inhibitory effects of active TGF-beta, the use of members of the steroid hormone superfamily for inducing this potent growth inhibitor locally at the tumor site may have therapeutic potential.