INTRAVENOUS VITAMIN C SUPPLEMENTATION IN ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANT RECIPIENTS: SALUTARY IMPACT ON CLINICAL OUTCOMES.

Intravenous (IV) vitamin C improves organ function and reduces inflammation in sepsis, an inflammatory state like the post-hematopoietic stem cell transplant (SCT) milieu. The safety and efficacy of parenteral vitamin C after allogeneic hematopoietic stem cell transplant (HSCT) were evaluated in a phase I/II trial and clinical outcomes compared with a propensity score - matched historical control. Methods: Patients with advanced hematologic malignancies were enrolled in a phase 2 clinical trial, receiving IV vitamin C, 50mg/kg/d, divided into 3 doses given on days 1-14 after HSCT, followed by 500 mg bid oral from day 15 until 6 months post-SCT. Results: 55 patients received IV vitamin C: these include 10/10 HLA-MRD and MUD (n=48) and 9/10 HLA MUD recipients (n=7). All patients enrolled were deficient in vitamin C at day 0 and had restoration to normal levels for the remainder of the course. Vitamin C recipients had lower non-relapse mortality (11% vs. 25%, p-value = 0.07) and consequently, improved survival compared to historical controls (82% vs 62% p=0.06), with no attributable grade 3 and 4 toxicities to vitamin C. Patients with myeloid malignancies had improved survival (83% vs. 54%, p=0.02) and non-relapse mortality (NRM) (10% vs. 37%, p=0.009), as well as chronic GVHD, with similar relapse rates compared to controls. Conclusions: In patients undergoing allogeneic HSCT the administration of IV vitamin C is safe and reduces non-relapse mortality improving overall survival. Randomized trials are needed to confirm the utility of this easily available and inexpensive therapy.

Temporal map of the pig polytrauma plasma proteome with fluid resuscitation and intravenous vitamin C treatment.

BACKGROUND: Fluid resuscitation plays a prominent role in stabilizing trauma patients with hemorrhagic shock yet there remains uncertainty with regard to optimal administration time, volume, and fluid composition (e.g., whole blood, component, colloids) leading to complications such as trauma-induced coagulopathies (TIC), acidosis, and poor oxygen transport. Synthetic fluids in combination with antioxidants (e.g., vitamin C) may resolve some of these problems. OBJECTIVES: We applied quantitative mass spectrometry-based proteomics [liquid chromatography-mass spectrometry (LC-MS/MS)] to map the effects of fluid resuscitation and intravenous vitamin C (VitC) in a pig model of polytrauma (hemorrhagic shock, tissue injury, liver reperfusion, hypothermia, and comminuted bone fracture). The goal was to determine the effects of VitC on plasma protein expression, with respect to changes associated with coagulation and trauma-induced coagulopathy (TIC). METHODS: Longitudinal blood samples were drawn from nine male Sinclair pigs at baseline, 2 h post trauma, and 0.25, 2, and 4 h post fluid resuscitation with 500 mL hydroxyethyl starch. Pigs were treated intravenously (N = 3/treatment group) with saline, 50 mg VitC/kg (Lo-VitC), or 200 mg VitC/kg (Hi-VitC) during fluid resuscitation. RESULTS: A total of 436 plasma proteins were quantified of which 136 changed following trauma and resuscitation; 34 were associated with coagulation, complement cascade, and glycolysis. Unexpectedly, Lo-VitC and Hi-VitC treatments stabilized ADAMTS13 levels by ~4-fold (P = .056) relative to saline and enhanced ADAMTS13/von Willebrand factor (VWF) cleavage efficiency based on LC-MS/MS evidence for the semitryptic VWF cleavage product (VWF1275-1286 ). CONCLUSIONS: This study provides the first comprehensive map of trauma-induced changes to the plasma proteome, especially with respect to proteins driving the development of TIC.

Platelets retain inducible alpha granule secretion by P-selectin expression but exhibit mechanical dysfunction during trauma-induced coagulopathy.

Essentials Platelets in trauma-induced coagulopathy (TIC) are impaired, but the mechanism is not known. We performed comprehensive longitudinal platelet function testing in trauma patient samples. Platelets in TIC are widely impaired early after injury, but platelet activatability is intact. This suggests a mechanism of transient platelet cytoskeletal/integrin dysfunction during TIC. SUMMARY: Background Trauma-induced coagulopathy (TIC) is a common and deadly bleeding disorder. Platelet dysfunction is present during TIC, but its mechanisms remain unclear. Platelets are currently thought to become "exhausted," a state in which they have released their granule contents and can no longer aggregate or contract. Methods This prospective observational cohort study tested the hypothesis that platelet exhaustion is present during TIC and characterized the early time course of platelet dysfunction. Blood was collected from 95 adult trauma patients at a Level I trauma center at time of Emergency Department arrival and several time points over 72 h. Platelet activation state and function were characterized using CD62P (P-selectin) and PAC-1 surface membrane staining, platelet function analyzer (PFA-100), aggregometry, viscoelastic platelet mapping, and, to test for exhaustion, their ability to express CD62P after ex vivo adenosine diphosphate (ADP) agonism. Platelet function was compared between patients with and without TIC, defined by prothrombin time ≥18 s. Results Platelets in TIC showed no initial increase in their level of surface activation markers or impairment of their capacity to express CD62P in response to ADP stimulation. However, TIC platelets were impaired in nearly all functional assays, spanning adhesion, aggregation, and contraction. These effects largely remained after controlling for platelet count and fibrinogen concentration and resolved after 8 h. Conclusion The TIC platelets exhibit early impairment of adhesion, aggregation, and contraction with retained alpha granule secretion ability, suggesting a specific mechanism of cytoskeletal or integrin dysfunction that is not a result of more general platelet exhaustion.

A Unique Nonsaccharide Mimetic of Heparin Hexasaccharide Inhibits Colon Cancer Stem Cells via p38 MAP Kinase Activation.

Targeting of cancer stem cells (CSC) is expected to be a paradigm-shifting approach for the treatment of cancers. Cell surface proteoglycans bearing sulfated glycosaminoglycan (GAG) chains are known to play a critical role in the regulation of stem cell fate. Here, we show for the first time that G2.2, a sulfated nonsaccharide GAG mimetic (NSGM) of heparin hexasaccharide, selectively inhibits colonic CSCs in vivo G2.2-reduced CSCs (CD133+/CXCR4+, Dual hi) induced HT-29 and HCT 116 colon xenografts' growth in a dose-dependent fashion. G2.2 also significantly delayed the growth of colon xenograft further enriched in CSCs following oxaliplatin and 5-fluorouracil treatment compared with vehicle-treated xenograft controls. In fact, G2.2 robustly inhibited CSCs' abundance (measured by levels of CSC markers, e.g., CD133, DCMLK1, LGR5, and LRIG1) and self-renewal (quaternary spheroids) in colon cancer xenografts. Intriguingly, G2.2 selectively induced apoptosis in the Dual hi CSCs in vivo eluding to its CSC targeting effects. More importantly, G2.2 displayed none to minimal toxicity as observed through morphologic and biochemical studies of vital organ functions, blood coagulation profile, and ex vivo analyses of normal intestinal (and bone marrow) progenitor cell growth. Through extensive in vitro, in vivo, and ex vivo mechanistic studies, we showed that G2.2's inhibition of CSC self-renewal was mediated through activation of p38α, uncovering important signaling that can be targeted to deplete CSCs selectively while minimizing host toxicity. Hence, G2.2 represents a first-in-class (NSGM) anticancer agent to reduce colorectal CSCs.

Interventional vitamin C: A strategy for attenuation of coagulopathy and inflammation in a swine multiple injuries model.

BACKGROUND: Coagulopathy and inflammation induced by hemorrhagic shock and traumatic injury are associated with increased mortality and morbidity. Vitamin C (VitC) is an antioxidant with potential protective effects on the proinflammatory and procoagulant pathways. We hypothesized that high-dose VitC administered as a supplement to fluid resuscitation would attenuate inflammation, coagulation dysfunction, and end-organ tissue damage in a swine model of multiple injuries and hemorrhage. METHODS: Male Sinclair swine (n = 24; mean body weight, 27 kg) were anesthetized, intubated, mechanically ventilated, and instrumented for physiologic monitoring. Following stabilization, swine were subjected to shock/traumatic injury (hypothermia, liver ischemia and reperfusion, comminuted femur fracture, hemorrhagic hypotension), resuscitated with 500 mL of hydroxyethyl starch, and randomized to receive either intravenous normal saline (NS), low-dose VitC (50 mg/kg; LO), or high-dose VitC (200 mg/kg; HI). Hemodynamics, blood chemistry, hematology, and coagulation function (ROTEM) were monitored to 4 hours postresuscitation. Histological and molecular analyses were obtained for liver, kidney, and lung. RESULTS: Compared with VitC animals, NS swine showed significant histological end-organ damage, elevated acute lung injury scores, and increased mRNA expression of tissue proinflammatory mediators (IL-1ß, IL-8, TNFα), plasminogen activation inhibitor-1 and tissue factor. There were no statistically significant differences between treatment groups on mean arterial pressure or univariate measures of coagulation function; however, NS showed impaired multivariate clotting function at 4 hours. CONCLUSION: Although correction of coagulation dysfunction was modest, intravenous high-dose VitC may mitigate the proinflammatory/procoagulant response that contributes to multiple organ failure following acute severe multiple injuries. LEVEL OF EVIDENCE: Prospective randomized controlled blinded trial study, Preclinical (animal-based).

Impact of high dose vitamin C on platelet function.

AIM: To examine the effect of high doses of vitamin C (VitC) on ex vivo human platelets (PLTs). METHODS: Platelet concentrates collected for therapeutic or prophylactic transfusions were exposed to: (1) normal saline (control); (2) 0.3 mmol/L VitC (Lo VitC); or (3) 3 mmol/L VitC (Hi VitC, final concentrations) and stored appropriately. The VitC additive was preservative-free buffered ascorbic acid in water, pH 5.5 to 7.0, adjusted with sodium bicarbonate and sodium hydroxide. The doses of VitC used here correspond to plasma VitC levels reported in recently completed clinical trials. Prior to supplementation, a baseline sample was collected for analysis. PLTs were sampled again on days 2, 5 and 8 and assayed for changes in PLT function by: Thromboelastography (TEG), for changes in viscoelastic properties; aggregometry, for PLT aggregation and adenosine triphosphate (ATP) secretion in response to collagen or adenosine diphosphate (ADP); and flow cytometry, for changes in expression of CD-31, CD41a, CD62p and CD63. In addition, PLT intracellular VitC content was measured using a fluorimetric assay for ascorbic acid and PLT poor plasma was used for plasma coagulation tests [prothrombin time (PT), partial thrombplastin time (PTT), functional fibrinogen] and Lipidomics analysis (UPLC ESI-MS/MS). RESULTS: VitC supplementation significantly increased PLTs intracellular ascorbic acid levels from 1.2 mmol/L at baseline to 3.2 mmol/L (Lo VitC) and 15.7 mmol/L (Hi VitC, P < 0.05). VitC supplementation did not significantly change PT and PTT values, or functional fibrinogen levels over the 8 d exposure period (P > 0.05). PLT function assayed by TEG, aggregometry and flow cytometry was not significantly altered by Lo or Hi VitC for up to 5 d. However, PLTs exposed to 3 mmol/L VitC for 8 d demonstrated significantly increased R and K times by TEG and a decrease in the α-angle (P < 0.05). There was also a fall of 20 mm in maximum amplitude associated with the Hi VitC compared to both baseline and day 8 saline controls. Platelet aggregation studies, showed uniform declines in collagen and ADP-induced platelet aggregations over the 8-d study period in all three groups (P > 0.05). Collagen and ADP-induced ATP secretion was also not different between the three groups (P > 0.05). Finally, VitC at the higher dose (3 mmol/L) also induced the release of several eicosanoids including thromboxane B2 and prostaglandin E2, as well as products of arachidonic acid metabolism via the lipoxygenases pathway such as 11-/12-/15-hydroxyicosatetraenoic acid (P < 0.05). CONCLUSION: Alterations in PLT function by exposure to 3 mmol/L VitC for 8 d suggest that caution should be exerted with prolonged use of intravenous high dose VitC.

Tolerability and Biological Effects of Long-Acting Octreotide in Patients With Continuous Flow Left Ventricular Assist Devices.

Patients with implanted continuous, nonpulsatile, left ventricular assist devices (LVADs) have increased the occurrence of gastrointestinal bleeding (GIB). Although the pathophysiology is multifactorial, there are few treatments beyond supportive care. Octreotide acetate is a somatostatin analog that reduces GIB in various patient populations. However, there are sparse case series that suggest octreotide acetate may reduce GIB in LVAD patients. This 10 patient, 28 week phase I study evaluated the safety and tolerability of octreotide acetate long-acting release (LAR) 20 mg depot injection every 4 weeks until week 16 after LVAD placement. Secondary aims were occurrence of GIB and measurement of vascular endothelial growth factor, fibrinogen, von Willebrand factor, and platelet aggregation across the study period. Ten patients were enrolled, and eight completed the study. The two study dropouts were not related to octreotide. None of the patients experienced side effects or safety concerns related to octreotide nor did GIB occur in the study population. Vascular endothelial growth factor levels were maintained in the reference range throughout the duration of the study. There did appear to be laboratory evidence of acquired von Willebrand syndrome, with mildly low platelet aggregation studies. In conclusion, octreotide acetate LAR 20 mg depot injection was safe and effective in this population.

Intact stable isotope labeled plasma proteins from the SILAC-labeled HepG2 secretome.

The plasma proteome remains an attractive biospecimen for MS-based biomarker discovery studies. The success of these efforts relies on the continued development of quantitative MS-based proteomics approaches. Herein we report the use of the SILAC-labeled HepG2 secretome as a source for stable isotope labeled plasma proteins for quantitative LC-MS/MS measurements. The HepG2 liver cancer cell line secretes the major plasma proteins including serum albumin, apolipoproteins, protease inhibitors, coagulation factors, and transporters that represent some of the most abundant proteins in plasma. The SILAC-labeled HepG2 secretome was collected, spiked into human plasma (1:1 total protein), and then processed for LC-MS/MS analysis. A total of 62 and 56 plasma proteins were quantified (heavy:light (H/L) peptide pairs) from undepleted and depleted (serum albumin and IgG), respectively, with log2 H/L = ± 6. Major plasma proteins quantified included albumin, apolipoproteins (e.g., APOA1, APOA2, APOA4, APOB, APOC3, APOE, APOH, and APOM), protease inhibitors (e.g., A2M and SERPINs), coagulation factors (e.g., Factor V, Factor X, fibrinogen), and transport proteins (e.g., TTR). The average log2 H/L values for shared plasma proteins in both undepleted and depleted plasma samples were 0.43 and 0.44, respectively. This work further expands the SILAC strategy into MS-based biomarker discovery of clinical biospecimens.

Resolution of sterile inflammation: role for vitamin C.

INTRODUCTION: Macrophage reprogramming is vital for resolution of acute inflammation. Parenteral vitamin C (VitC) attenuates proinflammatory states in murine and human sepsis. However information about the mechanism by which VitC regulates resolution of inflammation is limited. METHODS: To examine whether physiological levels of VitC modulate resolution of inflammation, we used transgenic mice lacking L-gulono-γ-lactone oxidase. VitC sufficient/deficient mice were subjected to a thioglycollate-elicited peritonitis model of sterile inflammation. Some VitC deficient mice received daily parenteral VitC (200 mg/kg) for 3 or 5 days following thioglycollate infusion. Peritoneal macrophages harvested on day 3 or day 5 were examined for intracellular VitC levels, pro- and anti-inflammatory protein and lipid mediators, mitochondrial function, and response to lipopolysaccharide (LPS). The THP-1 cell line was used to determine the modulatory activities of VitC in activated human macrophages. RESULTS: VitC deficiency significantly delayed resolution of inflammation and generated an exaggerated proinflammatory response to in vitro LPS stimulation. VitC sufficiency and in vivo VitC supplementation restored macrophage phenotype and function in VitC deficient mice. VitC loading of THP-1 macrophages attenuated LPS-induced proinflammatory responses. CONCLUSION: VitC sufficiency favorably modulates macrophage function. In vivo or in vitro VitC supplementation restores macrophage phenotype and function leading to timely resolution of inflammation.

Targeting the GPIbα binding site of thrombin to simultaneously induce dual anticoagulant and antiplatelet effects.

Exosite 2 of human thrombin contributes to two opposing pathways, the anticoagulant pathway and the platelet aggregation pathway. We reasoned that an exosite 2 directed allosteric thrombin inhibitor should simultaneously induce anticoagulant and antiplatelet effects. To assess this, we synthesized SbO4L based on the sulfated tyrosine-containing sequence of GPIbα. SbO4L was synthesized in three simple steps in high yield and found to be a highly selective, direct inhibitor of thrombin. Michelis-Menten kinetic studies indicated a noncompetitive mechanism of inhibition. Competitive inhibition studies suggested ideal competition with heparin and glycoprotein Ibα, as predicted. Studies with site-directed mutants of thrombin indicated that SbO4L binds to Arg233, Lys235, and Lys236 of exosite 2. SbO4L prevented thrombin-mediated platelet activation and aggregation as expected on the basis of competition with GPIbα. SbO4L presents a novel paradigm of simultaneous dual anticoagulant and antiplatelet effects achieved through the GPIbα binding site of thrombin.

Utilization Patterns of IV Iron and Erythropoiesis Stimulating Agents in Anemic Chronic Kidney Disease Patients: A Multihospital Study.

Intravenous (IV) iron and Erythropoiesis Stimulating Agents (ESAs) are recommended for anemia management in chronic kidney disease (CKD). This retrospective cohort study analyzed utilization patterns of IV iron and ESA in patients over 18 years of age admitted to University Health System Hospitals with a primary or secondary diagnosis of CKD between January 1, 2006 to December 31, 2008. A clustered binomial logistic regression using the GEE methodology was used to identify predictors of IV iron utilization. Only 8% (n = 6678) of CKD patients on ESA therapy received IV iron supplementation in university hospitals. Those receiving iron used significantly less amounts of ESAs. Patient demographics (age, race, primary payer), patient clinical conditions (admission status, severity of illness, dialysis status), and physician specialty were identified as predictors of IV iron use in CKD patients. Use of IV iron with ESAs was low despite recommendations from consensus guidelines. The low treatment rate of IV iron represents a gap in treatment practices and signals an opportunity for healthcare improvement in CKD anemic patients.

Characterizing hospitalizations of end-stage renal disease patients on dialysis and inpatient utilization of erythropoiesis-stimulating agent therapy.

BACKGROUND: In 2006, there were over 350,000 patients with end-stage renal disease (ESRD) receiving dialysis therapy. Studies have found that hemoglobin concentrations are often low among dialysis patients after hospital discharge, yet little is known about inpatient anemia treatment. OBJECTIVE: To characterize hospitalizations among patients with ESRD on dialysis, specifically, inpatient utilization of erythropoiesis-stimulating agent (ESA) therapy. METHODS: A cross-sectional, retrospective study of claims data from 5 commercial health plans for the years 2004-2006 was conducted. Inclusion criteria included 1 or more ESRD-specific International Classification of Diseases Ninth Edition (ICD-9) codes, 3 or more ESRD-specific Current Procedural Terminology/Healthcare Common Procedure Coding System (CPT/HCPCS) procedures on different days, or 3 or more dialysis ICD-9 codes or CPT/HCPCS dialysis procedures on separate days. ESRD patient and hospital characteristics were outlined. RESULTS: ESRD patients were hospitalized an average of 1.8 times in both 2004-2005 and 2005-2006. The mean +/- SD hospital length of stay (LOS) was 13.3 +/- 20.5 and 12.8 +/- 19.0 days for 2004-2005 and 2005-2006, respectively. For each year, LOS greater than 7 days occurred in 44% of hospitalizations. Many of these patients were admitted for kidney-related comorbidities and ultimately received procedures and services relevant to dialysis care. For each year, ESA utilization was 13% in year 1 and 11% in year 2 across any LOS. For ESRD patients with a 4- to 7-day LOS (the most common LOS), less than 20% received ESA treatment. ESA utilization increased correspondingly with longer hospital LOS (p < 0.001). CONCLUSIONS: Although ESRD patients are commonly hospitalized and claims recognize that kidney-related conditions exist, the utilization of ESAs is low.

Use and prescribing patterns for erythropoiesis-stimulating agents in inpatient and outpatient hospital settings.

PURPOSE: Erythropoiesis-stimulating agent (ESA) use in the outpatient and inpatient settings through pharmacist-conducted, hospital-based chart audits is examined and discussed. METHODS: Data from four hospital chart audits conducted in 250 hospitals between October 2005 and July 2006 were pooled for analyses. Eligible hospitals were categorized by ESA sales volume, with approximately equal numbers randomly selected from each decile. The last five inpatients and outpatients within each specified month receiving either darbepoetin alfa or epoetin alfa were evaluated. Study variables by setting included ESA use, prescriber specialty, and dosage regimen. RESULTS: The most common hospital locations of ESA administration were a cancer center in the outpatient setting (49%) and general medicine (57%) in the inpatient setting. ESA prescribers were most commonly hematologists and oncologists in the outpatient setting, and nephrologists were the most common prescribers in the inpatient setting. In the outpatient analysis, 2155 patients were prescribed darbepoetin alfa and 3106 were prescribed epoetin alfa. The predominant administration frequencies were every two weeks and once weekly for darbepoetin alfa, and once weekly for epoetin alfa. In the inpatient analysis, 1633 patients were prescribed darbepoetin alfa and 3231 were prescribed epoetin alfa. The predominant administration frequencies were once weekly for darbepoetin alfa and once weekly and three times weekly for epoetin alfa. Common uses for both ESAs were chemotherapy-induced anemia (outpatient setting) and anemia of end-stage renal disease with chronic dialysis (inpatient setting). There was considerable variability in ESA dosages and administration frequencies in both settings within all patient groups when analyzed by specified use. CONCLUSION: ESA use differed between outpatient and inpatient settings in indication, frequency of administration, and specialty of the prescriber.

Risk of infection with intravenous iron therapy.

OBJECTIVE: To review the potential risks of administering intravenous iron to patients with infection. DATA SOURCES: Literature was accessed through MEDLINE (1977-June 2007) and Google Scholar, using the terms intravenous iron, iron sucrose, ferric gluconate, iron dextran, and infection. In addition, reference citations from publications identified were reviewed. STUDY SELECTION AND DATA EXTRACTION: All English-language articles identified from the data sources were evaluated. Studies that provided data relevant to the objective were used, including in vitro and animal studies. DATA SYNTHESIS: The role of iron in bacterial growth and the pathophysiology of cellular immunity create legitimate, yet theoretical, concerns that active infection may be exacerbated by the administration of intravenous iron. Human data relating to this issue are limited. A few small, human studies in a population with chronic kidney disease suggest a possible increased risk of developing an infection associated with intravenous iron; however, prospective human data directly linking intravenous iron to exacerbation of existing infection or infection-related mortality are lacking. In vitro data suggest that increased transferrin saturation related to iron administration may result in polymorphonuclear leukocyte dysfunction and decreased inhibition of bacterial growth. Sparse animal data have linked intravenous iron therapy with morbidity and mortality in sepsis models. CONCLUSIONS: Despite the limited human data, careful consideration of risk versus benefit should be used when administering intravenous iron to patients with ongoing infection. Additional clinical data are needed to determine whether intravenous iron administration worsens outcomes of patients with infection.

Pharmacoeconomic considerations in the health system management of anaemia in patients with chronic kidney disease and end stage renal disease.

Anaemia is prevalent in patients with chronic kidney disease and end stage renal disease. If left untreated, it greatly affects patient survival, quality of life and functional status. Epoetin and darbepoetin are two biotechnology drugs that effectively stimulate the production of red blood cells. These drugs have been shown to significantly increase haemoglobin concentrations and improve quality of life. So far, there have been no head-to-head pharmacoeconomic studies that have compared epoetin to darbepoetin. Health system decision makers need to evaluate important considerations when comparing these agents. These considerations include drug acquisition costs, the patient population being treated, the location of drug administration (in-patient versus ambulatory) and federal government reimbursement. This review details these important pharmacoeconomic considerations.

Role of N-acetylcysteine in the prevention of radiocontrast-induced nephropathy.

OBJECTIVE: To examine the role of N-acetylcysteine (NAC) in the prevention of radiocontrast-induced nephropathy (RIN). DATA SOURCES: A literature search of MEDLINE (1966-December 2001) was performed using the following search terms: N-acetylcysteine, nephropathy, acute renal failure, and radiocontrast. STUDY SELECTION: Pertinent English-language animal and human studies were reviewed. DATA SYNTHESIS: Few small animal trials have demonstrated that NAC significantly prevents the development or reduces the severity of acute renal failure. Two human studies demonstrated NAC significantly reduces the occurrence of RIN. CONCLUSIONS: NAC may reduce the occurrence of RIN in high-risk patients. Further large-scale studies are needed to corroborate findings from earlier trials.