Sudhir K. Dutta

Vitamin C as an Antioxidant: Evaluation of Its Role in Disease Prevention

Vitamin C in humans must be ingested for survival. Vitamin C is an electron donor, and this property accounts for all its known functions. As an electron donor, vitamin C is a potent water-soluble antioxidant in humans. Antioxidant effects of vitamin C have been demonstrated in many experiments in vitro. Human diseases such as atherosclerosis and cancer might occur in part from oxidant damage to tissues. Oxidation of lipids, proteins and DNA results in specific oxidation products that can be measured in the laboratory. While these biomarkers of oxidation have been measured in humans, such assays have not yet been validated or standardized, and the relationship of oxidant markers to human disease conditions is not clear. Epidemiological studies show that diets high in fruits and vegetables are associated with lower risk of cardiovascular disease, stroke and cancer, and with increased longevity. Whether these protective effects are directly attributable to vitamin C is not known. Intervention studies with vitamin C have shown no change in markers of oxidation or clinical benefit. Dose concentration studies of vitamin C in healthy people showed a sigmoidal relationship between oral dose and plasma and tissue vitamin C concentrations. Hence, optimal dosing is critical to intervention studies using vitamin C. Ideally, future studies of antioxidant actions of vitamin C should target selected patient groups. These groups should be known to have increased oxidative damage as assessed by a reliable biomarker or should have high morbidity and mortality due to diseases thought to be caused or exacerbated by oxidant damage.

Microbiota Dynamics in Patients Treated with Fecal Microbiota Transplantation for Recurrent Clostridium difficile Infection

Clostridium difficile causes antibiotic-associated diarrhea and pseudomembraneous colitis and is responsible for a large and increasing fraction of hospital-acquired infections. Fecal microbiota transplantation (FMT) is an alternate treatment option for recurrent C. difficile infection (RCDI) refractory to antibiotic therapy. It has recently been discussed favorably in the clinical and scientific communities and is receiving increasing public attention. However, short- and long-term health consequences of FMT remain a concern, as the effects of the transplanted microbiota on the patient remain unknown. To shed light on microbial events associated with RCDI and treatment by FMT, we performed fecal microbiota analysis by 16S rRNA gene amplicon pyrosequencing of 14 pairs of healthy donors and RCDI patients treated successfully by FMT. Post-FMT patient and healthy donor samples collected up to one year after FMT were studied longitudinally, including one post-FMT patient with antibiotic-associated relapse three months after FMT. This analysis allowed us not only to confirm prior reports that RCDI is associated with reduced diversity and compositional changes in the fecal microbiota, but also to characterize previously undocumented post-FMT microbiota dynamics. Members of the Streptococcaceae, Enterococcaceae, or Enterobacteriaceae were significantly increased and putative butyrate producers, such as Lachnospiraceae and Ruminococcaceae were significantly reduced in samples from RCDI patients before FMT as compared to post-FMT patient and healthy donor samples. RCDI patient samples showed more case-specific variations than post-FMT patient and healthy donor samples. However, none of the bacterial groups were invariably associated with RCDI or successful treatment by FMT. Overall microbiota compositions in post-FMT patients, specifically abundances of the above-mentioned Firmicutes, continued to change for at least 16 weeks after FMT, suggesting that full microbiota recovery from RCDI may take much longer than expected based on the disappearance of diarrheal symptoms immediately after FMT.

Deficiency of Fat-Soluble Vitamins in Treated Patients with Pancreatic Insufficiency

Deficiency of fat-soluble vitamins (A,D,E, and K) was evaluated in 15 patients with exocrine pancreatic insufficiency secondary to chronic alcoholic pancreatitis. Mild to moderate steatorrhea was present in all patients despite oral pancreatic enzyme therapy for 27 +/- 4 months (mean +/- SE). Deficiency of a single fat-soluble vitamin was seen in six patients and deficiency of two fat-soluble vitamins was seen in two patients. One patient was deficient in three fat-soluble vitamins. Deficiency of vitamins A and E was most frequent. Treatment with specific vitamin supplements resulted in correction of these vitamin deficiencies. These data suggest that deficiency of a single or multiple fat-soluble vitamins is frequent even in treated patients with pancreatic insufficiency.

Vitamin E and its role in the prevention of atherosclerosis and carcinogenesis: a review.

Epidemiological and experimental studies suggest that antioxidants like vitamin E (α-tocopherol) may play an important role in prevention of chronic disease. Several observational surveys have linked populations with a large intake of vitamin E with reduced incidence of heart disease. These observations have been strengthened by the demonstration of strong antioxidant activity by vitamin E in cellular, molecular and animal experiments. These results have highlighted a potential role for vitamin E supplementation in the prevention of chronic disease in humans. Interestingly however, large-scale clinical trials of vitamin E and other antioxidants in preventing specific disease processes (e.g., coronary artery disease) have generated conflicting and mixed outcomes. In this review, the role of vitamin E in the prevention of atherosclerosis and carcinogenesis has been carefully examined with particular emphasis on salient human studies (clinical trials) and their limitations. In addition, pertinent biochemical, physiological and metabolic features of vitamin E have also been incorporated. A list of common natural food sources of vitamin E has been provided. Important in vitro and animal studies related to the antiatherosclerotic and anticarcinogenic actions of vitamin E have been discussed in detail. Finally, the direction of future investigations in primary and secondary prevention of chronic diseases by vitamin E supplementation has been outlined.

Efficacy of Combined Jejunal and Colonic Fecal Microbiota Transplantation for Recurrent Clostridium difficile Infection

The prevalence of recurrent Clostridium difficile infection (RCDI) is increasing; fecal microbiota transplantation (FMT) is an effective therapy. However, there have been no studies of the efficacy of a single session of combined enteral and colonic FMT or characterizations of changes in the microbiota between donors and recipients. We performed a study of 27 patients with RCDI who were given a fixed volume of processed fecal filtrate via enteroscopy and colonoscopy in a single session. Patients were closely monitored, and fecal samples were collected from 2 patient-donor pairs for 16S rRNA analysis. All patients had reduced stool frequency, abdominal pain, white blood cell counts, and elimination of fecal C difficile toxin (P < .05). FMT increased microbial diversity, increasing proportions of Lachnospiraceae (phylum Firmicutes) and reducing proportions of Enterobacteriaceae. FMT was associated with marked changes in the composition of fecal microbiota in 2 patients with RCDI.

Functional and structural changes in parotid glands of alcoholic cirrhotic patients.

The parotid gland function and structure was studied in 30 patients with biopsy-proven alcoholic cirrhosis and in 43 age- and sex-matched alcoholic and nonalcoholic control subjects. Mean simulated parotid saliva flow rate was significantly (p less than 0.05) lower in patients with alcoholic cirrhosis as compared with alcoholic and nonalcoholic control subjects. A similar reduction was observed in mean basal parotid saliva flow rate in patients with alcoholic cirrhosis that reached statistical significance (p less than 0.05) in comparison with nonalcoholic control subjects. In addition, the concentration of sodium, bicarbonate, and total proteins in stimulated parotid saliva was significantly (p less than 0.005) lower in patients with alcoholic cirrhosis as compared with the two groups of control subjects. Sialograms in 6 patients with alcoholic cirrhosis did not reveal any obstructive lesion in the primary parotid duct or its branches. Histology of salivary tissue revealed an increase in the interstromal fatty infiltration, edema, and fibrosis without evidence of inflammatory reaction in 5 patients as compared with the control subjects. These data provide evidence for marked parotid gland dysfunction in patients with alcoholic cirrhosis presumably due to metabolic derangement and altered parotid gland structure.

Serum HSP70: a novel biomarker for early detection of pancreatic cancer.

Objectives Heat shock protein 70 (HSP70) is overexpressed in human pancreatic cancer cell lines. To determine if serum HSP70 levels are elevated in patients with pancreatic cancer and can function as a biomarker for early detection of pancreatic cancer. Methods Study subjects were divided into 3 groups: histologically proven pancreatic cancer (PC; n = 23), chronic pancreatitis (CP; n = 12), and matched normal control subjects (C; n = 10). Serum HSP70 levels were determined using a novel immunoelectrophoresis method developed and validated by the authors. Significance of difference between the groups was analyzed with analysis of variance (ANOVA). Receiver operating characteristic (ROC) curve analysis was performed to discriminate patients with pancreatic cancer from normal controls. Results The mean ± SE serum HSP70 levels in the PC, CP, and C groups were 1.68 ± 0.083 ng/mL, 0.40 ± 0.057 ng/mL, and 0.04 ng/mL, respectively. Serum HSP70 levels in the PC group were significantly higher compared with either the CP or C groups (P < 0.01). The sensitivity and specificity of elevated serum HSP70 in the PC group was 74% and 90%, respectively. Conclusions Serum HSP70 levels are significantly increased in patients with pancreatic cancer and may be useful as an additional biomarker for the detection of pancreatic cancer.

Modulation of salivary secretion by acid infusion in the distal esophagus in humans

To examine the relationship between esophageal acid exposure and development of salivation and heartburn, 15 healthy subjects underwent perfusion of the distal esophagus with varying concentrations of hydrochloric acid, different-osmolality saline solutions, and deionized water. In five study subjects, hydrochloric acid was infused in the body of the stomach only. During the study, timed samples of whole and parotid saliva were collected and analyzed for flow rate and bicarbonate concentration. Only hydrochloric acid concentrations of 20 mmol/L or greater (pH 1.8 or lower) induced a rapid (within 2 minutes) and significant (P < 0.05) increase in salivation. The hydrochloric acid-induced salivation was associated with significant (P < 0.05) increase in bicarbonate secretion in both parotid and whole saliva samples. Intravenous atropine administration completely inhibited hydrochloric acid-induced salivary secretion in all six subjects. Changes in osmolality of saline solution infused in the esophagus and hydrochloric acid infused in the stomach did not significantly alter parotid and whole saliva flow rates. These data suggest that in humans, rapid salivation in response to esophageal mucosal exposure to intraluminal hydrochloric acid is a pH-dependent and osmolality-independent phenomenon that is most likely mediated by pH-sensitive chemoreceptors located in the esophageal mucosa.

Prospective evaluation of the risk of bacteremia and the role of antibiotics in ERCP

To determine the frequency of bacteremia associated with endoscopic retrograde cholangiopancreatography (ERCP), we obtained blood cultures before, during, and after ERCP in 51 consecutive patients. Patients with radiographically demonstrated abnormalities in pancreatic and/or biliary ducts were routinely given antibiotic therapy after ERCP. Bacteremia after successful cannulation of the papilla of Vater was observed in only one patient with multiple strictures of the main pancreatic duct. No episodes of acute febrile illness was observed in any patient during the 48-hour follow-up period after ERCP. Our observations suggest that the risk of bacteremia from ERCP is minimal, and that any possibility of sepsis after ERCP in patients with abnormal pancreatic or biliary ducts may be prevented by administering appropriate antibiotics after the procedure.

Coprocytobiology: on the nature of cellular elements from stools in the pathophysiology of colonic disease.

Abstract The gastrointestinal epithelium is known to undergo constant and rapid renewal resulting in millions of cells being shed into the fecal stream every day. The conventional wisdom was that these cells disintegrate upon exfoliation and will not survive the transit through the intestinal tract. In 1990, we (P.N.) made the discovery that a significant number of these cells remain intact and viable and that they can be isolated. The implications of this important discovery became apparent when we demonstrated that these cells are exclusively of colonic origin, are anatomically representative of the entire colon, and can be used for clinical investigations of disease processes. The term coprocytobiology (CCB) was coined to encompass the broad range of applications of this new technology. The somatic cell sampling and recovery (SCSR) process involves the isolation of exfoliated colonocytes from a small sample of stool (≈1 g) collected and transported in a unique medium at ambient temperature, providing cells for the detection of a number of biomarkers of disease propensity. These exfoliated colonocytes express cytokeratins indicating epithelial lineage as well as colon‐specific antigen. Over the years, the study of exfoliated colonocytes has provided striking new insights into the biology of colon cancer and inflammatory bowel disease, including detection of p53 gene mutations, reverse transcriptase polymerase chain reaction amplification, and identification of CD44 splice variants, neoplasia‐associated specific binding of plant lectins, and expression of COX‐2, the inducible form of cyclooxygenase. The functional diversity of cells isolated by SCSR is revealed by the demonstration of cell surface markers such as secretory component, IgA, and IgG on the one hand and the amplification and cloning of the human insulin receptor and the expression of the multidrug resistance gene mdr‐1 on the other hand. This review portrays the immense potential of CCB as a powerful tool for investigating the pathophysiology of disease, identifying genetic variants in pharmacogenetics, assessment of mucosal immunity, and several other applications that use somatic cells.