Luis Uscanga

Pancreatic Extracellular Matrix Alterations in Chronic Pancreatitis

The proliferation of pancreatic extracellular matrix, which characterizes chronic pancreatitis, has been analysed using immunohistochemistry. The relationship of matrix components to intraductal precipitates and the presence of serum proteins in precipitates were also studied to investigate the suggestion that ductal permeability increases in chronic pancreatitis. Pancreatic tissue from organ donors was compared with that from patients with chronic calcifying or chronic obstructive pancreatitis. Frozen sections were labeled with monospecific antibodies to collagen types I, III, pro-III and IV, laminin, fibronectin, IgG, IgA, and IgM and then visualized by indirect immunofluorescence. In chronic pancreatitis, interstitial collagens and fibronectin appeared increased and disorganized in both fibrous tissue and areas that appeared histologically normal. Type IV collagen distribution was abnormal and in some sites was present with interstitial collagen. In addition, intraductal precipitates were shown to contain immunoglobulins, and defects were identified in the duct basal lamina associated with precipitates. These results demonstrate that in chronic pancreatitis interstitial collagens are extensively disorganized, the fibrosis possibly being relatively labile. The presence of serum proteins in intraductal precipitates confirms an increase in ductal permeability, and associated defects in the basal lamina appear to define a route via which serum proteins may enter the intraluminal compartment.

Laparoscopic drainage of pancreatic pseudocysts.

Background. Laparoscopic drainage of pancreatic pseudocysts (PPs) has been used in selected cases. The aim of this study is to analyze our results with the laparoscopic technique and to compare them with those of a cohort of patients treated by open surgery during the same time period.Patients and methods. Ten patients underwent laparoscopic drainage of PPs during a 7-year period [laparoscopic group (LG)]. The type of drainage was chosen according to the size and location of the PP. Demography, surgical details, results, and complications were analyzed and contrasted with those of 6 patients who underwent open drainage [open group (OG)].Results. All patients presented with mature PPs developed after a documented episode of acute pancreatitis. Mean age of the LG was 42 years (six males and four females). In the OG, mean age was 36 years (five males and one female). Etiology of the pancreatitis was alcoholic in eight patients, biliary in five, toxic in two, and associated with systemic lupus erythematous in one. Laparoscopic procedures included Roux-en-Y cystojejunostomy in four patients, extraluminal cystogastrostomy in four, and intraluminal cystogastrostomy in two. There were no conversions. In the OG, cystogastrostomy was performed in three patients and Roux-en-Y cystojejunostomy in three. One patient in the LG developed upper gastrointestinal bleeding the day after surgery that resolved uneventfully, one patient presented a postoperative abscess that required open drainage, and one patient presented a residual pseudocyst that was treated by endoscopy. Morbidity in the OG included a small bowel obstruction secondary to an internal hernia that required reoperation, pneumonia, and a residual pseudocyst that was treated conservatively in one patient each. At a median follow-up of 22 months (range, 1–72) all patients were asymptomatic with no evidence of recurrent disease by computed tomography scan.Conclusion. Laparoscopic drainage of PPs is feasible, safe, and effective. Results are similar to those obtained using the open technique.

Sequential connective matrix changes in experimental acute pancreatitis. An immunohistochemical and biochemical assessment in the rat

SummaryThe effects of acute pancreatitis on the rat pancreatic connective tissue matrix were studied following intraductal pancreatic injection of trypsin solution and serial killing of the animals. Pancreatic tissue was examined using light microscopy, hydroxyproline measurement and indirect immunofluorescence, using antibodies against collagen types I, III, IV, procollagen III, fibronectin and laminin. Light microscopy revealed that acute pancreatitis was present for up to four days after injection and that perilobular and intralobular fibrosis appeared at four days and subsequently regressed.Immunofluorescence studies demonstrated an abnormal fibronectin deposit at one day in acute pancreatitis. At four days this deposit was co-located with fibrosis which was composed of collagen and procollagen type III. By eight days the immunofluorescence and light microscopic changes were minimal. Biochemical analysis confirmed a significant rise in hydroxyproline concentration at four days, which was maximal at eight days, subsequently decreasing. This peak at eight days probably reflects collagen breakdown products.

Immunolocalization of Collagen Types, Laminin and Fibronectin in the Normal Human Pancreas

In order to define the connective matrix organization of the normal human pancreas collagen types I, III, pro-III and IV, laminin and fibronectin were labeled using specific, antihuman antibodies. Visualization was by indirect immunofluorescence. Collagen types I, III and pro-III were present within lobules: around acini, ducts and small vessels. Their immunofluorescence reaction was particularly obvious in septa and it also outlined interlobular vessels and ducts. The type III and pro-III fractions possessed a characteristic, branched appearance in many situations, when compared to the more linear type I reaction. Collagen type IV, laminin and fibronectin were closely applied to acini, ducts and vessels, but in contrast to the other collagen types were absent from septa.

Nutritional data and etiology of chronic pancreatitis in Mexico

Alcoholism and malnutrition have been implicated commonly in the etiology of chronic pancreatitis (CP). The geographical distribution and clinical and nutritional features differ between the alcoholic and tropical forms of CP. This works presents the etiology and nutritional characteristics of CP in Mexico, a country in which both alcoholism and childhood malnutrition are common. Two well-defined groups of patients have been identified: an alcoholic group composed mainly of males with a mean age at clinical onset of 41 years and a high dietary intake of fat, protein, carbohydrates, and calories; and a nonalcoholic groups with a female preponderance, a mean age at onset of 23 years, and a higher intake of protein than controls. We conclude that alcoholic chronic pancreatitis in Mexico is similar to that reported in other temperate countries. Although the nonalcoholic group resembles that obseved in tropical countries in many ways, our patients are not malnourished, further questioning the role of childhood malnutrition in the pathogenesis of this type of chronic pancreatitis.

Follow-up of patients with pseudotumoral chronic pancreatitis: Outcome and surveillance

AIM To follow up patients with pseudotumoral chronic pancreatitis (PCP) to assess their outcome and identify an optimal surveillance interval. METHODS Data obtained prospectively were analyzed in a retrospective manner. Patients with clinical evidence of chronic pancreatitis (abdominal pain in the epigastrium, steatorrhea, and diabetes mellitus), endoscopic ultrasound (EUS) criteria > 4, and EUS-fine needle aspiration (FNA) were included. A pseudotumor was defined as a non-neoplastic space-occupying lesion, a cause of chronic pancreatitis that may mimic changes typical of pancreatic cancer on CT or endoscopic ultrasound but without histological evidence. A real tumor was defined as a neoplastic space-occupying lesion because of pancreatic cancer confirmed by histology. RESULTS Thirty-five patients with chronic pancreatitis were included, 26 (74.2%) of whom were men. Nine (25.7%) patients were diagnosed with pseudotumoral chronic pancreatitis and two (2/35; 5.7%) patients with pseudotumoral chronic pancreatitis were diagnosed with pancreatic cancer on follow-up. The time between the diagnosis of pseudotumoral chronic pancreatitis and pancreatic adenocarcinoma was 35 and 30 d in the two patients. Definitive diagnosis of pancreatic adenocarcinoma was made by surgery. In the remaining six patients with pseudotumoral chronic pancreatitis, the median of follow-up was 11 mo (range 1-22 mo) and they showed no evidence of malignancy on surveillance. In the follow-up of patients without pseudotumoral chronic pancreatitis but with chronic pancreatitis, none were diagnosed with pancreatic cancer. According to our data, older patients with chronic pancreatitis are at risk of pseudotumoral chronic pancreatitis. CONCLUSION According to characteristics of patient, detection of PCP should lead a surveillance program for pancreatic cancer with EUS-FNA in < 1 mo or directly to surgical resection.

Diagnostic yield of endoscopic ultrasound in patients with hypoglicemia and insulinoma suspected.

Background and Objectives: Noninvasive imaging techniques have shown limitations to identify insulinomas. In few studies reported so far, endoscopic ultrasound (EUS) has proven to be able to locate lesions. The aim of this study was to compare the performance of computed tomography versus EUS for the detection of insulinomas. Materials and Methods: In a retrospective manner prospectively collected data were analyzed. Patients with hypoglucemia and hyperinsulinemia were included. Diagnostic yield was measured in relationship to sensitivity, specificity, positive predictive value, negative predictive value and accuracy. Surgical specimens were considered the gold standard. Results: Sensitivity, positive predictive value, and accuracy of EUS was 100%, 95.4% and 95.4%, respectively. In the case of CT the sensitivity was 60%, specificity 100%, positive predictive value 100%, negative predictive value 7%, and accuracy were 68%. Conclusions: EUS is useful in the preoperative assessment of patients with hypoglycemia and serum hyperinsulinemia.