Therapeutic efficacy of high-dose vitamin C on acute pancreatitis and its potential mechanisms

Intravenous vitamin C in the treatment of shingles: results of a multicenter prospective cohort study

BACKGROUND

Vitamin C is an immune-relevant micronutrient, which is depleted in viral infections and this deficiency seems to play a critical role in the pathogenesis of herpes infections and in the development of postherpetic neuralgia. The objective of this observational multicenter study was to evaluate the utilization, safety and efficacy of intravenously administrated vitamin C in patients with shingles.

MATERIAL/METHODS

Between April 2009 and December 2010 16 general practitioners recorded data of 67 participants with symptomatic herpes zoster who received vitamin C intravenously (Pascorbin® 7.5 g/50 ml) for approximately 2 weeks in addition to standard treatment. The assessment of pain (VAS) and the dermatologic symptoms of shingles such as hemorrhagic lesions and the number of efflorescences were investigated in a follow-up observation phase of up to 12 weeks.

RESULTS

Mean declines of pain scores (VAS), number of affected dermatomes and efflorescences, and the presence of hemorrhagic vesicles between the baseline and follow-up assessments at 2 and 12 weeks were statistically significant. Overall, 6.4% of the participants experienced post-herpetic neuralgia. Common complaints such as general fatigue and impaired concentration also improved during the study. The effects and the tolerability of the treatment were evaluated positively by the physicians. The risk of developing PHN was reduced.

CONCLUSIONS

The data presented here provide evidence that concomitant use of intravenously administered ascorbic acid may have beneficial effects on herpes zoster-associated pain, dermatologic findings and accompanying common complaints. To confirm our findings, randomized, placebo-controlled clinical studies are necessary.

[Guidelines for specialized nutritional and metabolic support in the critically ill-patient. Update. Consensus of the Spanish Society of Intensive Care Medicine and Coronary Units-Spanish Society of Parenteral and Enteral Nutrition (SEMICYUC-SENPE): severe acute pancreatitis]

Severe acute pancreatitis (SAP) causes local and systemic complications leading to high catabolic, hypermetabolic and hyperdynamic stress states with marked morbidity and mortality. In the last decade, nutritional support has become a key element in the treatment of SAP. Thus, specialized nutrition is indicated from admission, with enteral nutrition being preferred to parenteral nutrition. Enteral nutrition should be initiated early using infusion through the jejunum beyond the ligament of Treitz to minimize pancreatic stress. There are no specific studies that establish the type of diet to be used but experts recommend the use of polymeric diets. Parenteral nutrition, without a specific formula, is indicated in patients with SAP who are intolerant to enteral nutrition or when the clinical signs of pancreatitis are exacerbated or aggravated by enteral nutrition. Even so, a minimal level of enteral infusion should be maintained to preserve the trophic effect of the intestinal mucosa. In the last few years, several studies of the administration of immunomodulatory diets in patients with SAP have been carried out to demonstrate their effects on the course of the disease. However, there are few clear recommendations on the prognostic benefits of pharmaconutrient enriched diets in these patients. There is substantial scientific evidence suggesting that the only clear indication for pharmaconutrition in patients with SAP is parenteral glutamine administration, which is recommended by all clinical guidelines with distinct grades of evidence.

Antioxidant therapy in acute pancreatitis: experimental and clinical evidence

SIGNIFICANCE

Oxidative stress plays an important role in the pathogenesis of both acute and chronic pancreatitis. Although its impact is well investigated and has been studied clinically in chronic pancreatitis, it is less well defined for acute pancreatitis.

RECENT ADVANCES

Pathophysiological aspects of oxidative stress in acute pancreatitis have shown that reactive oxidative species (ROS) participate in the inflammatory cascade, and mediate inflammatory cell adhesion and consecutive tissue damage. Furthermore, ROS are involved in the generation of pain as another important clinical feature of patients suffering from acute pancreatitis.

CRITICAL ISSUES

Despite sufficient basic and experimental knowledge and evidence, the step from bench to bedside has not been successfully performed. Only a limited number of clinical studies are available that can give convincing evidence for the use of antioxidants in the clinical setting of acute pancreatitis.

FUTURE DIRECTIONS

Future studies are required to evaluate potential benefits of antioxidative substances to attenuate the severity of acute pancreatitis. Special focus should be put on the aspect of pain generation and the progression from mild to severe acute pancreatitis in the clinical setting.

Calcium and reactive oxygen species in acute pancreatitis: friend or foe?

SIGNIFICANCE

Acute pancreatitis (AP) is a debilitating and, at times, lethal inflammatory disease, the causes and progression of which are incompletely understood. Disruption of Ca(2+) homeostasis in response to precipitants of AP leads to loss of mitochondrial integrity and cellular necrosis.

RECENT ADVANCES

While oxidative stress has been implicated as a major player in the pathogenesis of this disease, its precise roles remain to be defined. Recent developments are challenging the perception of reactive oxygen species (ROS) as nonspecific cytotoxic agents, suggesting that ROS promote apoptosis that may play a vital protective role in cellular stress since necrosis is avoided.

CRITICAL ISSUES

Fresh clinical findings have indicated that antioxidant treatment does not ameliorate AP and may actually worsen the outcome. This review explores the complex links between cellular Ca(2+) signaling and the intracellular redox environment, with particular relevance to AP.

FUTURE DIRECTIONS

Recent publications have underlined the importance of both Ca(2+) and ROS within the pathogenesis of AP, particularly in the determination of cell fate. Future research should elucidate the subtle interplay between Ca(2+) and redox mechanisms that operate to modulate mitochondrial function, with a view to devising strategies for the preservation of organellar function.

Intravenous ascorbic acid to prevent and treat cancer-associated sepsis?

The history of ascorbic acid (AA) and cancer has been marked with controversy. Clinical studies evaluating AA in cancer outcome continue to the present day. However, the wealth of data suggesting that AA may be highly beneficial in addressing cancer-associated inflammation, particularly progression to systemic inflammatory response syndrome (SIRS) and multi organ failure (MOF), has been largely overlooked. Patients with advanced cancer are generally deficient in AA. Once these patients develop septic symptoms, a further decrease in ascorbic acid levels occurs. Given the known role of ascorbate in: a) maintaining endothelial and suppression of inflammatory markers; b) protection from sepsis in animal models; and c) direct antineoplastic effects, we propose the use of ascorbate as an adjuvant to existing modalities in the treatment and prevention of cancer-associated sepsis.

A short overview of vitamin C and selected cells of the immune system

Vitamin C (ascorbic acid) is an essential water-soluble nutrient that primarily exerts its effect on a host defense mechanisms and immune homeostasis and is the most important physiological antioxidant. Stable intake of vitamin C is essential for life in humans because the body does not synthesize it. Even the numerous studies have demonstrated that vitamin C supplementation stimulates the immune system, prevents DNA damage and significantly decreases the risk of a wide range of pathologies; the potential protective mechanisms are still largely unknown. This review summarizes the recently known facts about the role of vitamin C on the selected cells of the immune system and potential molecular mechanisms involved. Further, in this review, many new data about the positive effects of vitamin C on the immune system, potential toxicological effects, vitamin C supplementation in disease development, as well as some proposed mechanisms of vitamin C activity, are discussed.

Safety and efficacy of vitamin-based antioxidant therapy in patients with severe acute pancreatitis: a randomized controlled trial

BACKGROUND/AIM

Oxidative stress plays a major role in the pathogenesis of pancreatitis. Antioxidant therapy in the form of high-dose vitamin has been used for the treatment of severe acute pancreatitis with equivocal results. We wished to evaluate the efficacy and safety of antioxidant (vitamin A, vitamin C, vitamin E) therapy in patients with severe acute pancreatitis.

SETTING AND DESIGN

This was a single-center, prospective, randomized, open-label with blinded endpoint assessment study of antioxidant therapy, conducted in the emergency department attached to our hospital.

MATERIALS AND METHODS

Thirty-nine patients with severe acute pancreatitis were randomly assigned to antioxidant treatment group (n=19) or a control group (n=20) within 96 hours of developing symptoms. Patients in the antioxidant group received antioxidants (vitamin A, vitamin E, vitamin C) in addition to the standard treatment provided to both the groups for a period of 14 days. The primary outcome variable was presence of organ dysfunction at day 7. The secondary outcome variables were length of hospital stay, multiorgan dysfunction (MODS) at day 7, recovery at the end of 4 weeks, complications, and mortality. The change in markers of oxidative stress from baseline was also measured.

RESULTS

We demonstrated no significant difference in organ dysfunction (P=1.0), MODS (P=0.8), and length of hospital stay (P=0.29) between the two groups. All the patients survived in the antioxidant-treated group, whereas two patients died in the control group. The change in the levels of malondialdehyde, superoxide dismutase, and reduced glutathione were not significantly different in the two groups at day 7. Univariate analysis showed marginal benefit with antioxidant treatment (P=0.034) in patients with severe acute pancreatitis.

CONCLUSIONS

This randomized study demonstrates that there is no significant benefit from antioxidant therapy in patients with established severe acute pancreatitis.

Mega-dose vitamin C attenuated lung inflammation in mouse asthma model

Asthma is a Th2-dependent disease mediated by IgE and Th2 cytokines, and asthmatic patients suffer from oxidative stresses from abnormal airway inflammation. Vitamin C is a micro-nutrient functioning as an antioxidant. When administered at a mega-dose, vitamin C has been reported to shift immune responses toward Th1. Thus, we tried to determine whether vitamin C exerted beneficial effects in asthma animal model. Asthma was induced in mice by sensitizing and challenging with ovalbumin. At the time of challenge, 3~5 mg of vitamin C was administered and the effects were evaluated. Vitamin C did not modulate Th1/Th2 balance in asthma model. However, it decreased airway hyperreactivity to methacholine, decreased inflammatory cell numbers in brochoalveolar lavage fluid, and moderate reduction of perivascular and peribronchiolar inflammatory cell infiltration. These results suggest that vitamin C administered at the time of antigen challenge exerted anti-inflammatory effects. Further studies based on chronic asthma model are needed to evaluate a long-term effect of vitamin C in asthma. In conclusion, even though vitamin C did not show any Th1/Th2 shifting effects in this experiment, it still exerted moderate anti-inflammatory effects. Considering other beneficial effects and inexpensiveness of vitamin C, mega-dose usage of vitamin C could be a potential supplementary modality for the management of asthma.

Beneficial effects of Emblica officinalis in L-arginine-induced acute pancreatitis in rats

Acute necrotizing pancreatitis is characterized by focal macroscopic or diffuse necrosis, hemorrhage, and vascular thrombosis of the pancreas. Current treatment options are limited to supportive and symptomatic interventions. A large amount of experimental work is ongoing to identify novel therapeutic agents for acute pancreatitis. The present study was carried out to explore the beneficial effects of Emblica officinalis, a medicinal plant of India, on acute pancreatitis. Ascorbic acid is one of the major chemical components of E. officinalis, so a vitamin C group was included for comparison. Acute pancreatitis was induced by L-arginine. Rats were divided into the following groups: control (saline), arginine + saline, arginine + E. officinalis, and arginine + vitamin C. Animals in each group were sacrificed at 24 hours and 3, 14, and 28 days after pancreatitis induction for determination of biochemical parameters and histological examination. For rate of DNA synthesis and immunohistochemical studies, animals were sacrificed on Day 3 and Day 7. Drug administration was started 2 hours after the last arginine injection and continued until the day of sacrifice. E. officinalis treatment was found to be beneficial for treating acute pancreatitis. Serum levels of lipase and interleukin-10 were significantly lower than in the arginine group. Nucleic acid content, rate of DNA synthesis, pancreatic proteins, and pancreatic amylase content were significantly improved. Histopathological examination showed significantly lower total scores in the Emblica group. Vitamin C was found to be less efficacious than E. officinalis for all outcome parameters. Thus E. officinalis treatment was found to be beneficial in acute necrotizing pancreatitis.

The efficacy of high doses of vitamin C in patients with paraquat poisoning

Paraquat (PQ) poisoning is an extremely difficult condition to manage clinically because of the lack of effective treatments. The purpose of this study was to assess the effect of high doses of vitamin C in combination with anti-inflammatory and immunosuppressant therapy in patients with PQ poisoning. The medical records of 134 patients who presented to the emergency department within 24 hours after PQ poisoning were reviewed retrospectively. The 57 patients presented between January 2004 and September 2005 were group 1; they received pulse therapy, which included cyclophosphamide and methylprednisolone, followed by the administration of dexamethasone over 2 weeks. The 77 patients that presented between October 2005 and January 2008 were group 2; they received the above-mentioned therapy and high-dose vitamin C for 2 weeks. There was no difference in the distribution of baseline variables between the 2 groups. However, group 2 showed a significant reduction in acute kidney injury related to PQ. Furthermore, a multivariate logistic regression analysis showed that the addition of vitamin C to the treatment was significantly associated with an increased survival of the patients. Larger trials will be needed to verify the effect of high-dose vitamin C on survival in patients with PQ poisoning.

Correlation of nitric oxide and other free radicals with the severity of acute pancreatitis and complicated systemic inflammatory response syndrome

OBJECTIVES

To investigate the correlation of nitric oxide (NO) and other free radicals with the severity of acute pancreatitis (AP) and complicated systemic inflammatory response syndrome (SIRS).

METHODS

Fifty AP patients (24 simple AP patients and 26 patients with AP complicated by SIRS) were involved in the study. Fifty healthy volunteers were included as controls. Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were evaluated, and plasma NO, plasma lipid peroxides, plasma vitamin E, plasma beta-carotene, whole-blood glutathione (GSH), and the activity of plasma GSH peroxidase were measured.

RESULTS

Compared with the control group, the APACHE II scores heightened in the AP group, and the SIRS group had the highest APACHE II scores (P < 0.005, P < 0.001, respectively). Plasma NO and plasma lipid peroxides increased with the heightening APACHE II scores, demonstrating a significant linear positive correlation (r = 0.618, r = 0.577, respectively; P < 0.001). Plasma vitamin E, plasma beta-carotene, whole-blood GSH, and the activity of plasma GSH peroxidase decreased with the heightening APACHE II scores, demonstrating a significant linear negative correlation (r = -0.600, r = -0.609, r = -0.559, r = -0.592, respectively; P < 0.001).

CONCLUSIONS

Nitric oxide and other free radicals take part in the aggravation of oxidative stress and oxidative injury and may play important roles in the pathogenesis of AP and SIRS. It may be valuable to measure free radicals to predict the severity of AP.

Nutritional strategies in severe acute pancreatitis: a systematic review of the evidence

Nutrition in severe acute pancreatitis is a critical aspect in the management of this condition. This review aims to systematically review the evidence available to inform the use of nutritional support in severe acute pancreatitis. High quality (level 1) evidence supports naso-jejunal enteral nutrition (NJ-EN) over parenteral nutrition (PN) reducing infectious morbidity and showing a trend towards reduced organ failure although there is no detectable difference in mortality. Trial data may underestimate benefit as patients are often recruited with predicted rather than proven severe disease. NJ-EN is safe when started immediately (level 3 evidence). NJ-EN is often impractical and naso-gastric (NG) feeding seems to be equivalent in terms of safety and outcomes whilst being more practical (level 2 evidence). Regarding feed supplementation, probiotic feed supplementation is not beneficial (level 1 evidence) the and may cause harm with excess mortality (level 2 evidence). No evidence exists to confirm benefit of the addition of prokinetics in severe acute pancreatitis (SAP) although their use is proven in other critically ill patients. Level 2 evidence does not currently support the use of combination immuno-nutrition though further work on individual agents may provide differing results. Level 2 evidence does not support intravenous supplementation of anti-oxidants and has demonstrated that these too may cause harm.

Antioxidant therapy in the management of acute, chronic and post-ERCP pancreatitis: A systematic review

We systematically reviewed the clinical trials which recruited antioxidants in the therapy of pancreatitis and evaluated whether antioxidants improve the outcome of patients with pancreatitis. Electronic bibliographic databases were searched for any studies which investigated the use of antioxidants in the management of acute pancreatitis (AP) or chronic pancreatitis (CP) and in the prevention of post-endoscopic retrograde cholangio-pancreatography (post-ERCP) pancreatitis (PEP) up to February 2009. Twenty-two randomized, placebo-controlled, clinical trials met our criteria and were included in the review. Except for a cocktail of antioxidants which showed improvement in outcomes in three different clinical trials, the results of the administration of other antioxidants in both AP and CP clinical trials were incongruent and heterogeneous. Furthermore, antioxidant therapy including allopurinol and N-acetylcysteine failed to prevent the onset of PEP in almost all trials. In conclusion, the present data do not support a benefit of antioxidant therapy alone or in combination with conventional therapy in the management of AP, CP or PEP. Further double blind, randomized, placebo-controlled clinical trials with large sample size need to be conducted.

ESPEN Guidelines on Parenteral Nutrition: pancreas

Assessment of the severity of acute pancreatitis (AP), together with the patient's nutritional status is crucial in the decision making process that determines the need for artificial nutrition. Both should be done on admission and at frequent intervals thereafter. The indication for nutritional support in AP is actual or anticipated inadequate oral intake for 5-7 days. This period may be shorter in those with pre-existing malnutrition. Substrate metabolism in severe AP is similar to that in severe sepsis or trauma. Parenteral amino acids, glucose and lipid infusion do not affect pancreatic secretion and function. If lipids are administered, serum triglycerides must be monitored regularly. The use of intravenous lipids as part of parenteral nutrition (PN) is safe and feasible when hypertriglyceridemia is avoided. PN is indicated only in those patients who are unable to tolerate targeted requirements by the enteral route. As rates of EN tolerance increase then volumes of PN should be decreased. When PN is administered, particular attention should be given to avoid overfeeding. When PN is indicated, a parenteral glutamine supplementation should be considered. In chronic pancreatitis PN may, on rare occasions, be indicated in patients with gastric outlet obstruction secondary to duodenal stenosis or those with complex fistulation, and in occasional malnourished patients prior to surgery.

Role of oxidative stress in pancreatic inflammation

Reactive oxygen and reactive nitrogen species (ROS/RNS) have been implicated in the pathogenesis of acute and chronic pancreatitis. Clinical and basic science studies have indicated that ROS/RNS formation processes are intimately linked to the development of the inflammatory disorders. The detrimental effects of highly reactive ROS/RNS are mediated by their direct actions on biomolecules (lipids, proteins, and nucleic acids) and activation of proinflammatory signal cascades, which subsequently lead to activation of immune responses. The present article summarizes the possible sources of ROS/RNS formation and the detailed signaling cascades implicated in the pathogenesis of pancreatic inflammation, as observed in acute and chronic pancreatitis. A therapeutic ROS/RNS-scavenging strategy has been advocated for decades; however, clinical studies examining such approaches have been inconsistent in their results. Emerging evidence indicates that pancreatitis-inducing ROS/RNS generation may be attenuated by targeting ROS/RNS-generating enzymes and upstream mediators.

The role of nutrients in modulating disease

The role of nutrition in the management of diseases has often centred on correcting apparent nutrient deficiencies or meeting estimated nutritional requirements of patients. Nutrition has traditionally been considered a supportive measure akin to fluid therapy and rarely it has been considered a primary means of ameliorating diseases. Recently, however, further understanding of the underlying mechanisms of various disease processes and how certain nutrients possess pharmacological properties have fuelled an interest in exploring how nutritional therapies themselves could modify the behaviour of various conditions. Nutrients such as omega-3 fatty acids, antioxidants and certain amino acids such as arginine and glutamine have all been demonstrated to have at least the potential to modulate diseases. Developments in the area of critical care nutrition have been particularly exciting as nutritional therapies utilising a combination of approaches have been shown to positively impact outcome beyond simply proving substrate for synthesis and energy. Application of certain nutrients for the modulation of diseases in veterinary patients is still in early stages, but apparent successes have already been demonstrated, and future studies are warranted to establish optimal approaches. This review describes the rationale of many of these approaches and discusses findings both in human beings and in animals, which may guide future therapy.

Anti-angiogenic effect of high doses of ascorbic acid

Pharmaceutical doses of ascorbic acid (AA, vitamin C, or its salts) have been reported to exert anticancer activity in vitro and in vivo. One proposed mechanism involves direct cytotoxicity mediated by accumulation of ascorbic acid radicals and hydrogen peroxide in the extracellular environment of tumor cells. However, therapeutic effects have been reported at concentrations insufficient to induce direct tumor cell death. We hypothesized that AA may exert anti-angiogenic effects. To test this, we expanded endothelial progenitor cells (EPCs) from peripheral blood and assessed, whether or not high dose AA would inhibit EPC ability to migrate, change energy metabolism, and tube formation ability. We also evaluated the effects of high dose AA on angiogenic activities of HUVECs (human umbilical vein endothelial cells) and HUAECs (human umbilical arterial endothelial cells). According to our data, concentrations of AA higher than 100 mg/dl suppressed capillary-like tube formation on Matrigel for all cells tested and the effect was more pronounced for progenitor cells in comparison with mature cells. Co-culture of differentiated endothelial cells with progenitor cells showed that there was incorporation of EPCs in vessels formed by HUVECs and HUAECs. Cell migration was assessed using an in vitro wound healing model. The results of these experiments showed an inverse correlation between AA concentrations relative to both cell migration and gap filling capacity. Suppression of NO (nitric oxide) generation appeared to be one of the mechanisms by which AA mediated angiostatic effects. This study supports further investigation into non-cytotoxic antitumor activities of AA.

Redox status of acute pancreatitis as measured by cyclic voltammetry: initial rodent studies to assess disease severity

OBJECTIVE

To determine whether serum antioxidant capacity as measured by the electrochemical technique cyclic voltammetry could be used to resolve differences in the severity of an inflammatory disease such as acute pancreatitis.

DESIGN

Experimental animal study.

SETTING

Animal laboratory, Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, New Zealand.

SUBJECTS

Male Wistar rats.

INTERVENTIONS

A total of 48 inbred male Wistar rats were studied in five experimental groups. Group 1 (baseline reference, immediate euthanasia, n = 14) had no surgical intervention. Group 2 (sham, n = 9) had identical surgical procedures to the pancreatitis groups except for the intraductal infusion. Groups 3-5 (n = 9, n = 10, and n = 6, respectively) had acute pancreatitis induced by the pancreatic intraductal infusion of 3%, 4%, or 5% sodium taurocholate, respectively. Groups 2-5 were killed after 12 hrs.

MEASUREMENTS AND MAIN RESULTS

Cyclic voltammetry involves scanning the voltage of a working electrode while recording the anodic current produced as the low molecular weight antioxidants in the solution are oxidized on the surface of the working electrode. The current produced is proportional to the combined concentration of the antioxidants. There was a significant positive correlation of the first cyclic voltammetric peak maximum with pancreatic histologic severity (Spearman's r = .51, p = .007) and with a number of other markers of systemic severity, notably bicarbonate (r = -.57, p = .002), base excess (r = -.65, p < .001), urea (r = .68, p < .001), and calcium (r = -.60, p = .008). The first cyclic voltammetric peak maximum was superior at indicating the severity of the disease state compared with a standard method of total antioxidant capacity measurement.

CONCLUSIONS

In experimental pancreatitis, the first cyclic voltammetric peak maximum showed significant correlations with histologic and systemic indices of severity. Further clinical studies are now needed to define the role of cyclic voltammetry in monitoring the progression of this and other severe illness in the critical care setting.

Comparative effects of several therapatic agents on hepatic damage induced by acute experimental pancreatitis

PURPOSE

The prognosis of acute pancreatitis (AP) depends upon the degree of pancreatic necrosis and the intensity of multisystem organ failure. The liver contributes to the systemic manifestations of AP by releasing some cytokines. This study was undertaken to examine comparative effects of melatonin, antioxidant mixture containing L(+)-ascorbic acid and N-acetyl cysteine, pentoxifylline and L-arginine on hepatic damage induced by caerulein-pancreatitis.

RESULTS

The liver specimens of all groups showed histopathological alterations such as hepatocyte necrosis, intracellular vacuolization, vascular congestion, sinusoidal dilatation and inflammatory infiltration. TEM studies revealed vacuole formation, mitochondrial degeneration, lysosome accumulation and necrosis. The mean histopathological score of the caerulein group was significantly different from that of each treatment group.

CONCLUSION

L-Arginine and antioxidant administration be important for reducing hepatic damage induced by AP. Improvement of hepatic damage, in turn, might be beneficial for the prognosis of AP.

Monocyte subsets and natural killer cells in acute pancreatitis

BACKGROUND

Alteration of the immune system is one of the major mechanisms responsible for complications in severe acute pancreatitis (AP). The aim of our study was to provide a complex evaluation of peripheral blood monocyte subsets, natural killer cells (NK cells) and cytotoxic T lymphocytes in patients with different severity forms of AP.

METHODS

20 patients with mild AP and 15 with severe AP (S-AP) were included in our study. Peripheral blood mononuclear cells were studied on days 1-3, 5, 10 and 30, by means of flow cytometry.

RESULTS

In peripheral blood of patients with pancreatitis, we found a marked increase in total monocyte count. In S-AP, circulating monocytes were significantly activated, which was presumed from increased expression of HLA-DR, CD54, CD69 and CD25. Concurrent increased expression of CD95 (FasR) may indicate enhanced susceptibility of these cells to apoptosis. In patients with S-AP, a dramatic depletion of circulating NK cells (CD16/56 and CD3- CD8+) was found along with a reduction of circulating CD3+ CD8+ lymphocytes (cytotoxic T lymphocytes).

CONCLUSION

Our findings suggest profound disturbances of innate cellular immunity in patients with S-AP.

Ascorbic acid alleviates pancreatic damage induced by dibutyltin dichloride (DBTC) in rats

PURPOSE

Because previous studies have reported depleted antioxidant capacity in patients with chronic pancreatitis (CP), prevention of free radical production has gained importance in antifibrotic treatment strategies for CP. The aim of this study was to investigate the effects of ascorbic acid on oxidative capacity and pancreatic damage in experimental CP.

MATERIALS AND METHODS

CP was induced in male Sprague-Dawley rats by infusion of dibutyltin dichloride (DBTC) into the tail vein. Ascorbic acid was given intraperitoneally at a daily dose of 10 mg/kg body weight. The treatment groups were as follows: group 1, DBTC plus intraperitoneal physiologic saline; group 2, DBTC plus intraperitoneal ascorbic acid; group 3, solvent plus intraperitoneal physiologic saline; group 4, no operation plus intraperitoneal physiologic saline. Each group contained 15 animals. Treatment was started after CP was established. After 4 weeks of treatment, serum hyaluronic acid and laminin levels were determined by radioimmunoassay, pancreatic tissue oxidative stress was analyzed, and the degree of pancreatic damage was determined.

RESULTS

Ascorbic acid treatment markedly increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) concentrations in pancreatic tissue (p < 0.01 for both). Significant serum hyaluronic acid and laminin reductions were observed in group 2 as compared with group 1 (p < 0.05). However, the serum hyaluronic acid and laminin levels remained elevated when compared with those of groups 3 and 4 (p < 0.05). Histopathologic scores were also lower in animals with CP that underwent ascorbic acid-treatment (p < 0.05).

CONCLUSION

Ascorbic acid treatment alleviated the degree of oxidative stress and pancreatic damage in rat CP. Antioxidant treatment might be considered a potential option to improve the pathologic process in CP.

From acute pancreatitis to end-organ injury: mechanisms of acute lung injury

BACKGROUND

Multi-organ dysfunction, and in particular lung injury, is often responsible for the unfavorable outcome of patients with severe acute pancreatitis. Understanding of the mechanisms by which local inflammation in the pancreas leads to end-organ injury is crucial for the development of new therapeutic strategies.

METHODS

A MEDLINE search was performed with the terms "acute pancreatitis," "lung injury," "inflammatory response," "SIRS," and "multi-organ dysfunction." Pertinent articles were selected for analysis.

RESULTS

Modulation of the inflammatory response using a combination of immunomodulatory agents may decrease the incidence of severe pancreatitis-related acute lung injury and acute respiratory distress syndrome.

CONCLUSION

Clinical trials are of utmost importance to establish the validity of such strategies.

Antioxidant therapy in critical care—Is the microcirculation the primary target?

This review presents the rationale for the therapeutic use of antioxidants in treating critically ill patients; it is not a systematic review of the clinical evidence that has been assessed recently by others. Clinical and nonclinical evidence is presented to support the notion that natural antioxidants are of therapeutic value in treating cardiovascular shock. Oxidative stress is a major promoter and mediator of the systemic inflammatory response. The microcirculation is particularly susceptible to oxidative stress that causes hemodynamic instability, leading to multiple organ failure due to systemic inflammatory response syndrome. Vitamin C is the antioxidant used experimentally to demonstrate oxidative stress as a key pathophysiologic factor in septic shock. Pharmacologic studies reveal that vitamin C (as ascorbate), at supraphysiologic doses, significantly affects the bioavailability of nitric oxide during acute inflammation, including inhibiting nitric oxide synthetase induction. Parenteral high-dose vitamin C inhibits endotoxin-induced endothelial dysfunction and vasohyporeactivity in humans and reverses sepsis-induced suppression of microcirculatory control in rodents. In severe burn injury, in both animals and patients, parenteral high-dose vitamin C significantly reduces resuscitation fluid volumes. Therefore, a significant body of pharmacologic evidence and sound preliminary clinical evidence supports the biological feasibility of using the exemplary antioxidant, vitamin C, in the treatment of the critically ill.

Update: effects of antioxidant and non-antioxidant vitamin supplementation on immune function

The purpose of this manuscript is to review the impact of supplementation with vitamins E and C, carotenoids, and the B vitamins on parameters of innate and adaptive immune function as reported from clinical trials in humans. There is evidence to support causal effects of supplementation with vitamins E and C and the carotenoids singly and in combination on selected aspects of immunity, including the functional capacity of innate immune cells, lymphocyte proliferation, and the delayed-type hypersensitivity (DTH) response. Controlled intervention trials of B vitamin-containing multivitamin supplements suggest beneficial effects on immune parameters and clinical outcomes in HIV-positive individuals.

Rationale and impact of vitamin C in clinical nutrition

PURPOSE OF REVIEW

The impact of vitamin C on oxidative stress-related diseases is moderate because of its limited oral bioavailability and rapid clearance. Parenteral administration can increase the benefit of vitamin C supplementation as is evident in critically ill patients. The aim here is to assess recent evidence of the clinical benefit and underlying effects of parenteral vitamin C in conditions of oxidative stress.

RECENT FINDINGS

In critically ill patients and after severe burns, the rapid restoration of depleted ascorbate levels with high-dose parenteral vitamin C may reduce circulatory shock, fluid requirements and oedema.

SUMMARY

Oxidative stress is associated with reduced ascorbate levels. Ascorbate is particularly effective in protecting the vascular endothelium, which is especially vulnerable to oxidative stress. The restoration of ascorbate levels may have therapeutic effects in diseases involving oxidative stress. The rapid replenishment of ascorbate is of special clinical significance in critically ill patients who experience drastic reductions in ascorbate levels, which may be a causal factor in the development of circulatory shock. Supraphysiological levels of ascorbate, which can only be achieved by the parenteral and not by the oral administration of vitamin C, may facilitate the restoration of vascular function in the critically ill patient.

Alteration of peripheral blood lymphocyte subsets in acute pancreatitis

AIM: To evaluate peripheral blood lymphocyte subsets in patients with acute pancreatitis (AP).

METHODS: Twenty patients with mild AP (M-AP) and 15 with severe AP (S-AP) were included in our study. Peripheral blood lymphocytes were examined at d 1-3, 5, 10 and 30 by means of flow cytometry.

RESULTS: A significant depletion of circulating lymphocytes was found in AP. In the early AP, the magnitude of depletion was similar for T- and B- lymphocytes. In the late course of S-AP, B-lymphocytes were much more depleted than T-lymphocytes. At d 10, strong shift in the CD7+/CD19+ ratio implicating predominance of T- over B-lymphocytes in S-AP was found. Among T-lymphocytes, the significant depletion of the CD4+ population was observed in M-AP and S-AP, while CD8+ cells were in the normal range. Lymphocytes were found to strongly express activation markers: CD69, CD25, CD28, CD38 and CD122. Serum interleukin-2 (IL-2), IL-4, IL-5, IL-10, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) levels were significantly increased in both forms of AP. The magnitude of elevation of cytokines known to be produced by Th2 was much higher than cytokines produced by Th1 cells.

CONCLUSION: AP in humans is characterized by significant reduction of peripheral blood T- and B-lymphocytes.

Ultrastructural clues for the protective effect of ascorbic acid and N-acetylcysteine against oxidative damage on caerulein-induced pancreatitis

BACKGROUND

Oxygen free radicals (OFR) have been implicated in the induction of acute pancreatitis (AP).

AIMS

The aim of this study was to determine the effect of ascorbic acid and N-acetylcysteine (NAC), potent antioxidants, against oxidative stress in AP.

METHODS

AP was induced by two i.p. injections of caerulein at 2-hour intervals (50 microg/kg BW). One group received additionally an antioxidant mixture composed of L(+)-ascorbic acid (14.3 mg/kg BW) and NAC (181 mg/kg BW) i.p. The rats were sacrificed 12 h after the last injection. Oxidative stress markers were evaluated. Light-microscopic and ultrastructural examination was performed.

RESULTS

Formation of vacuoles, mitochondrial damage, and dilatation of rough endoplasmic reticulum, margination and clumping of chromatin were major ultrastructural alterations in AP group. Ascorbic acid + NAC prevented these changes. Small vacuoles were present within the cytoplasm of some of the acinar cells. Pancreas damage was accompanied by an increase in tissue malondialdehyde (MDA) levels (p < 0.05), whereas a decrease was seen in catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) activities and total glutathione (GSH) levels (p < 0.005). Ascorbic acid + NAC decreased MDA levels but increased CAT, SOD, GPx activities and GSH levels (p < 0.005).

CONCLUSION

These results suggest that ascorbic acid + NAC is potentially capable of limiting pancreatic damage produced during AP via protecting fine structure of acinar cells and tissue antioxidant enzyme activities.

Pro- and anti-inflammatory response of acinar cells during acute pancreatitis. Effect of N-acetyl cysteine

We investigate the ability of acinar cells to produce tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) at different stages of acute pancreatitis (AP). Since oxidative stress is involved in the inflammatory response, the effect of N-acetyl cysteine (NAC) has also been evaluated. AP was induced in rats by bile-pancreatic duct obstruction (BPDO). NAC (50 mg/kg) was administered 1h before and 1h after BPDO. Acinar cells were incubated for 4 h at 37 degrees C in 5% CO2 atmosphere in absence and presence of 24-h BPDO-PAAF (20%, v/v) as stimulant agent. Acinar production of TNF-alpha and IL-10 was analysed by flow cytometry. Plasma amylase activity and histological studies of the pancreas indicated the severity of AP. PAAF significantly stimulated the acinar production of TNF-alpha and IL-10 in control rats. TNF-alpha production was also significantly stimulated in acinar cells of rats with AP, although a decrease in the pro-inflammatory response was found from 6 h after BPDO onwards. However, acinar cells failed to produce IL-10 from 3 h after BPDO. The protective effect of NAC treatment against oxidative cell damage reduced the pancreatic injury and maintained and enhanced the ability of acinar cells to produce IL-10 at early AP stages. As long as acinar cells were not severely damaged in the course of AP, greater ability to produce cytokines in response to PAAF was found in those with higher forward scatter (R2 cells). We suggest that the capability of acinar cells to maintain an appropriate balance between the production of pro- and anti-inflammatory mediators could contribute to determine the degree of severity of AP.

Especies reactivas de oxígeno en las enfermedades inflamatorias del páncreas: ¿una posible diana terapéutica?

Chronic and acute pancreatitis can be understood as distinct stages of an inflammatory spectrum in the pancreas. Although its pathogenesis is not well defined, oxidative stress seems to be clearly involved in its development. During acute pancreatitis, there is an extraordinary and rapid formation of reactive oxygen species that leads to the extinction of pancreatic antioxidant reserves, causes direct tissue damage and activates oxidative cellular mediators, giving rise to the lesion. However, classical antioxidants have not been shown to have clear benefits in patients with acute pancreatitis. Chronic pancreatitis seems to be the result of a recurrent lesion and defective repair, leading to pancreatic atrophy and fibrosis. In this process, oxidative stress is an efficient stimulus to maintain pancreatic stellar cells active, the fibrogenic motor of chronic pancreatitis. Although antioxidant supplements relieve abdominal pain in these patients, the direction of future antioxidant therapies lies in identifying oxidative mechanisms with the potential for intervention.

Mega-dose Vitamin C modulates T cell functions in Balb/c mice only when administered during T cell activation

Previously we reported that a mega-dose of Vitamin C enhanced the initial stage of delayed-type hypersensitivity reaction in Balb/c mice. In this study its effects were further evaluated as follows. Mice were administered Vitamin C intraperitoneally at 0.625 mg/day or at 5mg/day for variable days before, during, or after being sensitized with DNFB. T cells were isolated in each group and examined. When stimulated antigen-specifically or non-specifically in vitro, mice showed elevated thymidine uptake and a shift of cytokine secretion profiles toward Th1, i.e., elevated levels IL-2, TNF-alpha, and IFN-gamma, and lowered level of the Th2 cytokine IL-4, only when Vitamin C was administered during sensitization. T cells from those mice administered Vitamin C before sensitization or after challenge showed the same T cell properties as those from PBS-treated mice. Mice were also given 0.625 mg/day of Vitamin C during primary and/or secondary immunizations with KLH and secondary specific antibody titers in sera were measured. The total specific antibody titer was lowered in Vitamin C-treated animals whenever treatments were administered, and this was entirely attributed to decreased levels of IgG1 and IgE antibodies. Based on these results, we suggest that an exogenously administered mega-dose of Vitamin C shifts immunity in Balb/c mouse toward Th1 and that these affects occur only when Vitamin C is administered during T cell activation.