Exacerbation of colon carcinogenesis by Blastocystis sp.

Colorectal cancer (CRC) is one the most commonly diagnosed cancers worldwide and the number is increasing every year. Despite advances in screening programs, CRC remains as the second leading cause of cancer deaths in the United States. Oxidative stress plays an important role in the molecular mechanisms of colorectal cancer (CRC) and has been shown to be associated with Blastocystis sp., a common intestinal microorganism. In the present study, we aimed to identify a role for Blastocystis sp. in exacerbating carcinogenesis using in vivo rat model. Methylene blue staining was used to identify colonic aberrant crypt foci (ACF) and adenomas formation in infected rats whilst elevation of oxidative stress biomarker levels in the urine and serum samples were evaluated using biochemical assays. Histological changes of the intestinal mucosa were observed and a significant number of ACF was found in Blastocystis sp. infected AOM-rats compared to the AOM-controls. High levels of urinary oxidative indices including advanced oxidative protein products (AOPP) and hydrogen peroxide were observed in Blastocystis sp. infected AOM-rats compared to the uninfected AOM-rats. Our study provides evidence that Blastocystis sp. has a significant role in enhancing AOM-induced carcinogenesis by resulting damage to the intestinal epithelium and promoting oxidative damage in Blastocystis sp. infected rats.

Blastocystis sp. in Irritable Bowel Syndrome (IBS)--Detection in Stool Aspirates during Colonoscopy.

Blastocystis is one of the most common gut parasites found in the intestinal tract of humans and animals. Its' association with IBS is controversial, possibly as a result of irregular shedding of parasites in stool and variation in stool detection. We aimed to screen for Blastocystis in colonic stool aspirate samples in adult patients with and without IBS undergoing colonoscopy for various indications and measure the interleukin levels (IL-8, IL-3 and IL-5). In addition to standard stool culture techniques, polymerase chain reaction (PCR) techniques were employed to detect and subtype Blastocystis. All the serum samples collected were subjected for ELISA studies to measure the interleukin levels (IL-8, IL-3 and IL-5). Among 109 (IBS n = 35 and non-IBS n = 74) adults, direct stool examination and culture of colonic aspirates were initially negative for Blastocystis. However, PCR analysis detected Blastocystis in 6 (17%) IBS and 4 (5.5%) non-IBS patients. In the six positive IBS patients by PCR method, subtype 3 was shown to be the most predominant (3/6: 50%) followed by subtype 4 (2/6; 33.3%) and subtype 5 (1/6; 16.6%). IL-8 levels were significantly elevated in the IBS Blasto group and IBS group (p<0.05) compared to non-IBS and non-IBS Blasto group. The level of IL-3 in were seen to be significantly higher in than IBS Blasto group and IBS group (p<0.05) compared to non-IBS. Meanwhile, the IL-5 levels were significantly higher in IBS Blasto group (p<0.05) compared to non-IBS and non-IBS Blasto group. This study implicates that detecting Blastosystis by PCR method using colonic aspirate samples during colonoscopy, suggests that this may be a better method for sample collection due to the parasite's irregular shedding in Blastocystis-infected stools. Patients with IBS infected with parasite showed an increase in the interleukin levels demonstrate that Blastocystis does have an effect in the immune system.

Factors that influence the shedding of Blastocystis cysts in an irritable bowel syndrome (IBS) patient--an evidence-based case study.

Blastocystis is one of the most common gut parasites found in the intestinal tract of humans and animals. We have previously reported the irregular shedding of Blastocystis cysts in stools from infected patients. In the present study, we assess the factors influencing shedding patterns from a Blastocystis ST3-infected IBS patient. The stools samples were voluntarily submitted for examination for a period of 30 days from Blastocystis ST3-infected IBS patient. A questionnaire on the factors that could influence the shedding pattern of the cysts was designed to assess the following information: (a) the frequency of frequenting the toilet in a day, (b) the timing of frequenting the toilet, (c) the stool forms, (d) the type of mood the patient was in when frequenting the toilet and (e) food intake. A total of 79 stool samples were collected for 30 days. The highest number of cysts recorded when the patient visited the toilet three times a day was 22.2 × 10(6) cysts/g. Frequenting the toilet between 6 a.m. to 11.59 a.m. showed the highest number of cysts, i.e. 21.7 × 10(6) cysts/g. Semi-solid forms showed the highest cyst count, i.e. 2.00 × 10(6) cysts/g. Irregular shedding of cysts was seen in 10 out of 30 days where the widest range recorded on day 17 was between 0 to 1.2 × 10(6) cysts/g. The average daily cyst count on days of emotional fluctuations was from 0 to 5.13 × 10(6) cysts/g. In conclusion, the study confirms that there are factors influencing shedding patterns of Blastocystis, and these have important implications when it comes to diagnosis and transmission of the parasite.

Phenotypic variation in Blastocystis sp. ST3.

BACKGROUND: Blastocystis, is one of the most common human intestinal protozoan, which has many conflicting reports on its pathogenic role. Gut conditions which obviously varies in asymptomatic individuals, symptomatic and irritable bowel syndrome (IBS) patients in terms of gut flora, pH, osmotic pressure and water potentials could play an important role in its pathogenicity. The present study is the first study to investigate phenotypic characteristics of Blastocystis sp. ST3 isolated from asymptomatic, symptomatic and IBS isolates. METHODS: A total of 8 Blastocystis isolates were obtained from four IBS patients (IBS1-4) and four symptomatic patients (S1-4) at a local gastroenterology clinic. Asymptomatic isolates (A1-4) were obtained from a field survey at a local village. RESULTS: All 12 isolates were determined as subtype 3 (ST3). A1-4 isolates showed the highest peak growth followed by IBS1-4 isolates and S1-4 isolates for the growth profile. Parasites from IBS isolates (IBS1-4) showed the largest diameter with a mean 18.43 ± 2.22 µm compared to parasites of symptomatic isolates (isolates S1-4) 15.54 ± 3.02 µm and asymptomatic isolates (isolates A1-4) 11.76 ± 0.82 µm. The symptomatic isolates (average generation time: 9.87 ± 2.97 h) grew faster than the IBS isolates (average generation time: 7.56 ± 1.06 h) and asymptomatic isolates (average generation time: 5.97 ± 1.52 h). The parasites isolated from IBS isolates showed strong aggregation and clumping, which had seen reduced in parasites of isolates S1-4. No clumping was seen in parasites from A1-4. The outer surface of parasites in IBS isolates showed greater binding affinities towards FITC-labelled Concanavalin A (Con A) than symptomatic isolates and asymptomatic isolates. Scanning electron microscopy showed that in IBS isolates, the surface of Blastocystis showed a very coarse and intensely folded surface. The IBS isolates also exhibited a dense material and a thicker layer of surface coat can be seen compared to asymptomatic and symptomatic isolates. CONCLUSION: There have been no studies thus far providing evidence for phenotypic variation within a particular subtype. The present study is the first to demonstrate the phenomenon of gut environment facilitating adaptation of parasites possibly for survival leading to phenotypic differences for Blastocystis.