Differential expression of miRNAs associated with pectoral myopathies in young broilers: insights from a comparative transcriptome analysis

INTRODUCTION

White Striping (WS) and Wooden Breast (WB) pectoral myopathies are relevant disorders for contemporary broiler production worldwide. Several studies aimed to elucidate the genetic components associated with the occurrence of these myopathies. However, epigenetic factors that trigger or differentiate these two conditions are still unclear. The aim of this study was to identify miRNAs differentially expressed (DE) between normal and WS and WB-affected broilers, and to verify the possible role of these miRNAs in metabolic pathways related to the manifestation of these pectoral myopathies in 28-day-old broilers.

RESULTS

Five miRNAs were DE in the WS vs control (gga-miR-375, gga-miR-200b-3p, gga-miR-429-3p, gga-miR-1769-5p, gga-miR-200a-3p), 82 between WB vs control and 62 between WB vs WS. Several known miRNAs were associated with WB, such as gga-miR-155, gga-miR-146b, gga-miR-222, gga-miR-146-5p, gga-miR- 29, gga-miR-21-5p, gga-miR-133a-3p and gga-miR-133b. Most of them had not previously been associated with the development of this myopathy in broilers. We also have predicted 17 new miRNAs expressed in the broilers pectoral muscle. DE miRNA target gene ontology analysis enriched 6 common pathways for WS and WB compared to control: autophagy, insulin signaling, FoxO signaling, endocytosis, and metabolic pathways. The WS vs control contrast had two unique pathways, ERBB signaling and the mTOR signaling, while WB vs control had 14 unique pathways, with ubiquitin-mediated proteolysis and endoplasmic reticulum protein processing being the most significant.

CONCLUSIONS

We found miRNAs DE between normal broilers and those affected with breast myopathies at 28 days of age. Our results also provide novel evidence of the miRNAs role on the regulation of WS and in the differentiation of both WS and WB myopathies. Overall, our study provides insights into miRNA-mediated and pathways involved in the occurrence of WS and WB helping to better understand these chicken growth disorders in an early age. These findings can help developing new approaches to reduce these complex issues in poultry production possibly by adjustments in nutrition and management conditions. Moreover, the miRNAs and target genes associated with the initial stages of WS and WB development could be potential biomarkers to be used in selection to reduce the occurrence of these myopathies in broiler production.

Diet and colorectal cancer: current evidence for etiology and prevention

The etiology of colorectal cancer (CRC) involves the interaction of cell molecular changes and environmental factors, with a great emphasis on diet components. But the paths connecting lifestyle characteristicas and the colorectal carcinogenesis remain unclear. Several risk factors are commonly found in western diets, such as high concentrations of fat and animal protein, as well as low amounts of fiber, fruits and vegetables. A large number of experimental studies have found a counteractive effect of fiber on neoplasia induction, especially in relation to fermentable fiber (wheat bran and cellulose). Epidemiological correlation studies have also indicated that a greater ingestion of vegetables, fruit, cereal and seeds is associated to a lower risk for colorectal neoplasia. Moreover, beneficial properties of fiber (especially from vegetable sources) were documented in more than half of case-control studies. Nevertheless, recent epidemiological data from longitudinal and randomized trials tended not to support this influence. Future research should evaluate what sources of fiber provide effective anti-neoplasic protection, carrying out interventional studies with specific fibers for longer periods. Red meat, processed meats, and perhaps refines carbohydrates are also implicated in CRC risk. Recommendantions to decrease red meat intake are well accepted, although the total amount and composition of specific fatty acids may have distinct roles in this setting. Current evidence favors the substitution of long and medium-chain fatty acids and arachidonic acid for short-chain fatty acids and eicosapentaenoic acid. Excess boy weight and excess energy intake inducing hyperinsulinemia have been also associated to CRC, as well as personal habits such as physical inactivy, high alcohol consumption, smoking and low consumption of folate and methionine. Thus, current recommendations for decreasing the risk of CRC include dietary measures such as increased plant food intake; the consumption of whole grains, vegetables and fruits; and reduced red meat intake.

Pharmacological nutrition in inflammatory bowel diseases

Inflammatory Bowel Diseases--ulcerative colitis and Crohn's disease--are chronic gastrointestinal inflammatory diseases of unknown etiology. Decreased oral intake, malabsorption, accelerated nutrient losses, increased requirements, and drug-nutrient interactions cause nutritional and functional deficiencies that require proper correction by nutritional therapy. The goals of the different forms of nutritional therapy are to correct nutritional disturbances and to modulate inflammatory response, thus influencing disease activity. Nutritional intervention may improve outcome in certain individuals; however, because of the costs and complications of such therapy, careful selection is warranted. Total parenteral nutrition has been used to correct and prevent nutritional disturbances and to promote bowel rest during active disease, mainly in cases of digestive fistulae with a high output. Its use should be reserved for patients who cannot tolerate enteral nutrition. Enteral nutrition is effective in inducing clinical remission of disease in adults and promoting growth in children. Recent research has focused on the use of specific nutrients as primary treatment agents. Although some reports have indicated that glutamine, short-chain fatty acids, antioxidants and immunonutrition with omega-3 fatty acids are an important therapeutic alternative in the management of inflammatory bowel diseases, the beneficial reported effects have yet to be translated into the clinical practice. The real efficacy of these nutrients still need further evaluation through prospective and randomized trials.

Impact of parenteral n-3 fatty acids on experimental acute colitis

The present study was undertaken to investigate the effects of parenteral lipid emulsions (LE) enriched with n-3 fatty acids (n-3 FA) in experimental acute colitis. Seventy-four adult male Wistar rats were randomized into six groups, five of which had acetic acid-induced colitis. The animals received a fat-free diet and water ad libitum in individual metabolic cages. By a central venous catheter, saline was infused (0.5 ml/h) into the control groups CS (without colitis) and CC (with colitis), while the test groups received specific LE for 7 days. The n-3/n-6 FA ratio and the lipidic compositions regarding long chain (LCT) and medium chain (MCT) triglycerides were: group L--1:7.7 (LCT, n = 12), M--1:7.0 (MCT and LCT, n = 12), LW-3--1:4.5 (LCT plus n-3 FA, n = 12) and MW-3--1:3.0 (MCT and LCT plus n-3 FA, n = 13). The frequency of diarrhea, oral intake/body weight ratio, intestinal alterations, macrophage cellularity were evaluated and colonic concentrations of leukotrienes (LTB4, LTC4), prostaglandins (PGE2) and thromboxanes (TXB2) were measured. Groups M, MW-3 and LW-3 had less diarrhea than the CC group (P<0.05). Average oral intake/body weight ratio in MW-3 animals was comparable to the CS and better than the CC group. n-3 FA treated rats (LW-3 and MW-3) presented less intestinal inflammatory alterations than CC rats. Mucosal ulcer formation in MW-3 group did not differ from CS rats. M and MW-3 rats had less macrophages in the colon than the CC group. Compared with CC group, lower concentrations of LTB4 in the CS, LW-3 and MW-3 groups; of PGE2 in the CS, M and MW-3 groups; and of TXB2 in the CS and MW-3 groups were found. Mean concentrations of LTC4 did not differ among the groups. Thus, a LCT-containing LE with a low n-3-n-6 ratio does not modify inflammatory colitis manifestations; LE with a high n-3-n-6 ratio reduces diarrhea, preserves oral intake-weight ratio, attenuates morphological consequences and decreases colonic concentrations of inflammatory mediators; MCT/LCT-containing LE with 1:3 n-3-n-6 ratio exerts the most profound beneficial impact on the inflammatory response.

Low rectal cancer: impact of radiation and chemotherapy on surgical treatment

INTRODUCTION

The aim of this study was to evaluate the impact of combined radiotherapy and chemotherapy (leucovorin and 5-fluorouracil) on the treatment of potentially resectable low rectal cancer using the following end points: 1) toxicity of this combined modality regimen; 2) clinical and pathologic response rate and local control; 3) down-staging of the tumor and its influence on the number of sphincter-saving operations; 4) disease-free interval, patterns of relapse, and overall survival.

METHODS

From 1991 to 1996, 118 patients with potentially resectable cases of histologically proven adenocarcinoma and no distant metastases were enrolled into this protocol. All patients were evaluated by clinical and proctologic examination, abdominal computed tomography, transrectal ultrasound, and chest radiography. Therapy consisted of 5,040 cGy (6 weeks) and concurrent leucovorin (20/mg/m2/day) with bolus doses of 5-fluorouracil administered intravenously at 425 mg/m2/day for three consecutive days on the first and last three days of radiation therapy. After two months, all patients underwent repeat evaluation and biopsy of any suspected residual lesions or scar tissue.

RESULTS

Median follow-up was 36 months. Toxicity of chemotherapy regimen was minimum. Thirty-six patients (30.5 percent) were classified as being complete responders. In six of these patients, complete response was confirmed by the absence of tumor in the surgical specimens (3 abdominoperineal resections and 3 proctosigmoidectomies with coloanal anastomosis). In the remaining 30 patients, confirmation of a complete response was made by the absence of symptoms, negative findings on physical examination, and biopsy, transrectal ultrasound, and pelvic computed tomographic test results during follow-up. Eighty-two patients (69.4 percent) were considered incomplete responders. Residual lesions had already been identified during the first examination in 74 patients. In the other eight patients, residual tumor was only identified after 3 to 14 months. All patients underwent surgical treatment, except one patient who refused surgery. Eighty-seven patients underwent 90 surgical procedures: local excision, 9; coloanal anastomosis, 36; abdominoperineal resection, 4; Hartmann's procedure, 1. Isolated local recurrences occurred in five patients (4.3 percent) and combined local and distant failure in eight patients (6.7 percent). Ninety patients are alive and disease-free at a median follow-up of 36 months.

CONCLUSIONS

Combined up-front chemoradiotherapy was associated with tolerable and acceptable side effects. A significant number of patients had complete disappearance of their tumors (30.5 percent) within a median follow-up of 36 months. This regimen spared 26.2 percent of patients from surgical treatment and allowed sphincter-saving management in 38.1 percent of patients who may have required abdominoperineal resection. Preliminary results of this trial suggests a reduction in the number of local recurrences and reinforces the concept that infiltrative low rectal cancer may be initially treated by chemoradiotherapy.

[Laparoscopic abdominoperineal resection of rectum. Analysis of 18 cases]

Laparoscopic abdominoperineal resection (APR-L) represents a truly laparoscopic operation which feasibility has been demonstrated by several authors. The wish to offer a minimally invasive procedure to patients that will deal with permanent colostomy was responsible for the authors' initial experience with the method which began in 1992. Hospital charts of patients who underwent APR-L to this date were reviewed and data regarding duration of the operation, intraoperative complications, need for conversion and characteristics of the postoperative period were assessed. Seventeen patients with the diagnosis of adenocarcinoma of the low rectum and one with squamous carcinoma of the anal canal underwent APR-L in a selective basis. The duration of the procedure was between two and six hours. There were no intraoperative complications. There was one conversion due to a large uterus that impaired pelvic dissection. One patient underwent laparotomy in the postoperative course as result of abdominal distension and incipient pelvic herniation of a small bowel wall through perineal wound. There were no septic complications and mean hospital stay was seven days. Perineal hernia occurring in the late postoperative period was seen in two patients. One of these underwent surgical correction through a conventional approach. Authors conclude that APR-L is feasible with low morbidity. Rectal oncologic dissection through video-laparoscopic access seems to be preserved and the method seems to be superior to the conventional access when considering that there is no need for abdominal incision.

[Technical and histological standardization of experimental colitis with trinitrobenzenosulfonic acid (TNBS)]

Attempts to reproduce inflammatory colitis have created many experimental models. Since the pioneer work of Morris et al. (1989), trinitrobenzenosulfonic (TNBS) solutions have been used with different dosages. The aims of this work were standardize the induction of colitis, evaluate the clinical and intestinal effects of different doses and verify the reproducibility of the intestinal inflammatory process. Wistar rats were inoculated endo rectally with 2.5 ml solutions of different concentrations of TNBS and ethanol, and the rats were sacrificed after 14 days. According to the solution concentrations of TNBS (mg) and ethanol (%), six groups of animals were established: Control (saline), 30 mg/30%, 30 mg/40%, 30 mg/50%, 50 mg/10% and 50 mg/30%. Statistical analysis of food ingestion showed no differences between groups (p = 0.247). The 30/50 group presented greater weight loss when compared to 50/10 and 50/30 groups (p = 0.012). Groups 30/50 and 30/40 showed greater degrees of macroscopic lesion than control and 50/10 group (p < 0.05). Histologic lesion was not uniform to all rats regardless of the solution employed. Group 50/10 presented the less severe histologic alterations; on the other hand, 30/40 and 30/50 groups had important changes on mucosal thickness, on vascularization and ulceration. The authors conclude that experimental colitis with TNBS 1) cause intestinal lesions that are not uniform to all animals, although they may be reproduced in many of them; 2) with the same doses of TNBS, the increase in ethanol concentrations leads to a greater inflammatory process, intestinal thickness, vascularization, abscess formation and intestinal ulceration; 3) 50/10 and 50/30 solutions make less severe lesions when compared to 30/40 and 30/50 solutions; 4) 30/50 solution was the best one, as it produces inflammation 90% of the animals, increases in wall thickness in 50%, abscess in 70% and ulceration in 38%.

Protective effects of glutamine enriched diets on acute actinic enteritis

Radiotherapy plays an important role in cancer treatment, although it may cause collateral effects and sever complications due to cellular damage of peritumoral tissues. Recently different nutritional resources have been indicated to achieve intestinal protection during cancer irradiation. The aim of this study was to set the role of glutamine in acute actinic enteritis prevention. Sixty-five Wistar male rats (200 g) were maintained in individual metabolic cages, where body weight and food ingestion were carefully monitored daily. The animals were chosen at random in three groups and fed isocaloric and isoproteid diets: 1) CRt (23)-polymeric-casein diet (CD); 2) GRt (22)-polymeric-casein diet supplemented with 2% glutamine (GD), and 3) ERt (20)--elemental diet supplemented with 2% glutamine (ED). After an adaptation period (seven days), all rats received 1500 cGy of abdominal radiation in five equal daily doses of 300 cGy. After three days post radiation the rats were submitted to jejunal perfusion test with polyethylene-glicol 4000. Finally, small bowel and colon were resected for histological evaluation. It was observed that ERt group had greater average daily food intake than CRt and GRt groups during all periods (p < 0.05). All rats had equal weight gain during adaptation period; during irradiation all the animals had weight loss, but ERt group had smaller weight loss than CRt. All rats recovered weight after irradiation, and ERt group presented better results than the others (p < 0.05). Sodium transepithelial transport average values (mEq/min/cm) were negative and not statistically different in all groups. Small bowel histological evaluation in ERt and GRt rats were better than CRt rats, by preserving mucosal cellularity and increasing mitosis number and villi length (p < 0.05). Simultaneously, ERt group had greater number of rats with normal villuscrypt relation than CRt of CRt groups (p < 0.05). Large bowel histological data showed that the average crypt's length in ERt and GRt rats were greater than in CRt ones (p < 0.05). By the present work, an elemental diet enriched with 2% glutamine favored greater food ingestion and lessened weight loss during and after radiotherapy. Glutamine-supplemented polymeric or elemental diets given to rats before, during and after abdominal radiotherapy showed protective effects against radiation injury, by supporting mucosal structure and recovery.

[The role of glutamine in nutrition in clinical practice]

Nutritional therapy using nutrients with pharmacological properties has been intensively discussed in the recent literature. Among these nutrients, glutamine has gained special attention. Glutamine is the most abundant amino acid in the blood stream of the mammals and, besides it has been considered a non-essential amino acid, glutamine is a non-dispensable nutrient in catabolic states. In this situation, there are alterations in its inter-organic flux, leading to lower plasmatic concentrations. Glutamine is the main fuel to enterocytes and it has an important role in the maintenance of intestinal structure and functions. Moreover, supplementation with glutamine has proved to be beneficial to the immunological system functions, improves nitrogen balance and nutritional parameters in the post-operative period and lessens protein loss in severe catabolic states. For these reasons, glutamine enriched-diets must be considered in the nutritional support of many diseases; new controlled, prospective and randomized studies will help to define what group of patients can really benefit from glutamine supplementation.

[Rectal endometriosis]

Colorectal endometriosis is a relatively rare entity that may have a wide array of clinical symptoms and radiographic findings. A 42-year-old female patient with rectal endometriosis treated with danazol under CA 125, CA 19-9 and estrogen monitoring is described. The treatment was successful and the patient underwent excision of reproductive organs without colorectal excision.

[Protective effects of glutamine and elemental diet in acute actinic enterocolitis: histological evaluation]

Radiotherapy plays nowadays an important role in malignancies treatment. However, collateral effects and severe complications owing to cellular damage of peritumoral tissues may occur. Different nutritional resources have been recently indicated to achieve intestinal protection during cancer irradiation. PURPOSE--The aim of this study was to set the role of glutamine and elemental diets in acute actinic enteritis prevention. METHOD--Sixty-five adult male Wistar rats with average weight of 200g were maintained in individual metabolic cages; daily body weight and food ingestion were carefully monitored. The animals were randomized into three groups and fed isocaloric and isonitrogenous diets: 1) CRt-polymeric-casein diet; 2) GRt-polymeric-casein diet supplemented with 2% glutamine and 3) ERt-elemental diet supplemented with 2% glutamine. After an adaptation period (seven days), all rats received abdominal radiation in five daily doses of 300cGy. Four days after the rats were operated on to resect the small intestine and colon for histological evaluation. RESULTS--Small intestine histological data in ERt and GRt rats were better than CRt rats, by preserving mucosal cellularity and increasing mitosis number and villi length. Simultaneously, ERt group had greater number of rats with normal villus-crypt relation than CRt or GRt groups. Large intestine histological data showed that the average crypts length in ERt and GRt rats were greater than in CRt ones. CONCLUSION--Glutamine-supplemented polymeric or elemental diets given to rats before, during and after abdominal radiotherapy showed protective effects against radiation injury, by supporting mucosal structure and recovery.

[Primary lymphomas of the large intestine]

Primary colorectal lymphomas are rare tumors that comprise 0.5 to 2% of large bowel malignancies and 10 to 20% of gastrointestinal lymphomas. Between 1982-1993 ten patients were treated in the Colorectal Unit of the "Hospital das Clínicas" of the University of São Paulo, representing 2% of the neoplasms in this period. Age varied from 22 to 76 years, with median around 50 years, and male/female ratio 8:2. Weight loss, right iliac palpable mass and bowel habit alterations were the most common symptoms. Definitive diagnostic was only set with histological evaluation of the surgical specimen in all colon tumors. Four patients had advanced disease classified as stages III or IV. The tumors were located in ileocecal region (7 cases), transverse colon (1 case), sigmoid colon (1 case) and rectum (1 case). Colon lymphomas were treated by radical surgical resection and chemotherapy; the patient with rectal lymphoma received radiotherapy and chemotherapy because of local tumor spread. Histological data showed 6 large cell lymphomas and 4 small cleaved cells lymphomas. Lymphnodal involvement and tumor size were the main prognostic factors in the series: 80% of the patients in advanced stage (III or IV) and 66% of those with tumors larger than 10 cm died during the first year of the follow-up.