Search PubMed⌕ Search

Biomedical subjects

K A Fleming

Publications and source records attributed to K A Fleming.

At least 19 recordsLinked to original sources
PubMed2002

Cigarette smoking, appendectomy, and tonsillectomy as risk factors for the development of primary sclerosing cholangitis: a case control study.

BACKGROUND AND AIMS: The strong clinical association between primary sclerosing cholangitis (PSC) and ulcerative colitis (UC) suggests common factors in their pathogenesis. Smoking, previous appendectomy, and tonsillectomy have been associated with a decreased risk of developing UC. In this study, our aim was to examine these risk factors in patients with PSC with and without underlying inflammatory bowel disease (IBD). METHODS: The smoking habits and history of previous appendectomy and/or tonsillectomy of 170 patients with PSC, 41 without underlying IBD, 170 patients with UC but normal liver function tests, and 170 age and sex matched community controls were obtained by questionnaire. RESULTS: A total of 112 PSC patients (66%) had never smoked compared with 66 controls (39%). Only 12 PSC patients (7%) were current smokers versus 43 controls (25%). The resultant odds ratio of having PSC was 0.17 (95% confidence interval (CI) 0.08-0.35) among current smokers and 0.33 (95% CI 0.21-0.52) among ever (former+current) smokers. Among former smokers, the odds of having PSC were also significantly decreased (odds ratio 0.45, 95% CI 0.26-0.73; p<0.05). In the subgroup of PSC patients without IBD, only 5% were current smokers versus 26% of matched controls, and never smokers were overrepresented (68% v 37%). The rate of previous appendectomy was similar in all three study groups (14%, 12%, and 13%) but the frequency of tonsillectomy was reduced in the PSC group (21% v 31%; p=0.05). CONCLUSION: PSC, like UC, is a disease of non-smokers as the odds of having PSC was significantly decreased among current and former smokers. The association between non-smoking and PSC was independent of whether the PSC patient had underlying IBD. Previous tonsillectomy but not appendectomy may also be associated with a decreased risk of PSC but this warrants further study.

Adult↗
PubMed2001

Biliary dysplasia as a marker of cholangiocarcinoma in primary sclerosing cholangitis.

BACKGROUND/AIMS: Indentification of biliary dysplasia in a primary sclerosing cholangitis (PSC) liver biopsy may indicate developing cholangiocarcinoma. The objectives were to determine whether biliary dysplasia can be recognised reproducibly in PSC and to compare the frequency in cases with and without cholangiocarcinoma. METHODS: Liver biopsies from 26 PSC cases with concurrent or subsequent cholangiocarcinoma (within 2 years) were assessed for biliary dysplasia independently by three liver pathologists. This was done in two stages: initially, without agreement on criteria, and subsequently after such agreement. Liver biopsies from 60 PSC cases without cholangio-carcinoma were also assessed. RESULTS: Reproducibility for biliary dysplasia without prior agreement on criteria was only marginally better than random (kappa=0.129). In contrast, after prior agreement on criteria, reproducibility was moderate (kappa=0.44). Biliary dysplasia was agreed to be present by all three pathologists in 23% and 19% of biopsies in the first and second round, respectively, from patients with cholangiocarcinoma, but in none of the patients without cholangiocarcinoma. CONCLUSION: Criteria for biliary dysplasia can be agreed and the entity recognised in liver biopsies. The strong association of biliary dysplasia with cholangiocarcinoma in PSC suggests use of dysplasia as a marker for current or developing malignancy.

Adult↗
PubMed2001

Primary sclerosing cholangitis associated with rheumatoid arthritis and HLA DR4: is the association a marker of patients with progressive liver disease?

In four cases we describe the unique association of primary sclerosing cholangitis (PSC) and rheumatoid arthritis (RA). In three of the cases the liver disease was unusually progressive, proceeding to cirrhosis in 14, 18 and 48 months from diagnosis. The three cases with progressive liver disease and ulcerative colitis were all HLA type DR4. The fourth patient also suffered from coeliac disease in addition to PSC and RA and has remained asymptomatic over 7 years of follow-up. RA in association with PSC may serve as a clinical marker of patients at high risk of progression to cirrhosis who need to be kept under particularly close observation. In addition, PSC needs to be considered in the differential diagnosis of all patients with RA and cholestatic liver function tests. This is especially important given the link between PSC and an increased risk of colonic carcinoma, and thus the need for surveillance colonoscopy.

Adult↗
PubMed2001

A preliminary trial of high-dose ursodeoxycholic acid in primary sclerosing cholangitis.

BACKGROUND & AIMS: Ursodeoxycholic acid (UDCA) is used for the treatment of cholestatic liver diseases including primary biliary cirrhosis (PBC) for which it has a positive effect on laboratory values, may delay the development of liver failure and prolong the transplant-free disease period. Standard doses of UDCA (8-15 mg/kg daily) have been shown to be ineffective in the treatment of primary sclerosing cholangitis (PSC). We report on the findings (clinical, biochemical, histological, and cholangiographic) and side effects of a 2-year double-blind placebo-controlled preliminary study of high-dose UDCA in PSC patients. METHODS: Twenty-six patients with PSC were randomized to high-dose (20 mg/kg daily) UDCA or placebo. Cholangiography and liver biopsy were performed at entry and after 2 years. Symptoms, clinical signs, and liver biochemical tests were recorded at 3 monthly intervals. RESULTS: High-dose UDCA did not influence symptoms, but there was a significant improvement in liver biochemistry (serum alkaline phosphatase, P = 0.03; gamma-glutamyl transferase, P = 0.01) and a significant reduction in progression in cholangiographic appearances (P = 0.015) and liver fibrosis as assessed by disease staging (P = 0.05). In the treatment group, a significant increase in total bile acids and saturation with UDCA >70% confirmed patient compliance. No significant side effects were reported. CONCLUSIONS: High-dose UDCA may be of clinical benefit in PSC, but trials with a larger number of participants and of longer duration are required to establish whether the effect of high-dose UDCA on liver biochemistry, histology, and cholangiography in patients with PSC is translated into improved long-term survival.

Adult↗
PubMed2001

Evaluation of serologic disease markers in a population-based cohort of patients with ulcerative colitis and Crohn's disease.

BACKGROUND: The sensitivity of assays for antineutrophil cytoplasmic antibody (ANCA), anti-Saccharomyces cerevisiae antibody (ASCA), and antipancreatic antibody (PAB) in different laboratories is unknown. Likewise, the sensitivity and diagnostic usefulness of these assays in patients with inflammatory bowel disease (IBD) in the community is unknown. METHODS: An incidence cohort of 290 patients with IBD were offered participation in the study. Blood was obtained from 162 patients (56%) (83 with ulcerative colitis, 79 with Crohn's disease) who agreed to participate. ANCA was determined in five laboratories. ASCA in two laboratories, and PAB in one laboratory. RESULTS: In ulcerative colitis, the sensitivity of ANCA determined in five laboratories varied widely, ranging from 0-63%. In Crohn's disease, the sensitivity of ASCA determined in two laboratories did not vary significantly, ranging from 39-44%; and the sensitivity of PAB determined in one laboratory was 15%. The optimal diagnostic usefulness was obtained from one laboratory where the positive predictive values of a positive ANCA assay combined with a negative ASCA assay for ulcerative colitis, and a negative ANCA combined with a positive ASCA for Crohn's disease, were 75% and 86%, respectively. CONCLUSIONS: In patients with IBD, the sensitivity of ANCA varied widely in different laboratories, whereas the prevalence of ASCA was similar. The positive predictive values of the ANCA assay combined with the ASCA assay for ulcerative colitis and Crohn's disease are high enough to be clinically useful.

Adolescent↗
PubMed2001

Association of the tumour necrosis factor alpha -308 but not the interleukin 10 -627 promoter polymorphism with genetic susceptibility to primary sclerosing cholangitis.

BACKGROUND AND AIMS: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown aetiology. Abnormalities in immune regulation and genetic associations suggest that PSC is an immune mediated disease. Several polymorphisms within the tumour necrosis factor alpha (TNF-alpha) and interleukin 10 (IL-10) promoter genes have been described which influence expression of these cytokines. This study examines the possible association between polymorphisms at the -308 and -627 positions in the TNF-alpha and IL-10 promoter genes, respectively, and susceptibility to PSC. METHODS: TNF-alpha -308 genotypes were studied by polymerase chain reaction (PCR) in 160 PSC patients from Norway and the UK compared with 145 ethnically matched controls. IL-10 -627 genotypes were studied by PCR in 90 PSC patients compared with 84 ethnically matched controls. RESULTS: A total of 16% of Norwegian PSC patients and 12% of British PSC patients were homozygous for the TNF2 allele compared with 3% and 6% of respective controls. The TNF2 allele was present in 60% of PSC patients versus 30% of controls (OR(combined data)=3.2 (95% confidence intervals (CI) 1.8--4.5); p(corr)=10(-5)). The association between the TNF2 allele and susceptibility to PSC was independent of the presence of concurrent inflammatory bowel disease (IBD) in the PSC patients; 61% of PSC patients without IBD had TNF2 compared with 30% of controls (OR(combined data)=3.2 (95% CI 1.2--9.0); p(corr)=0.006 ). There was no difference in the -627 IL-10 polymorphism distributions between patients and controls in either population. The increase in TNF2 allele in PSC patients only occurs in the presence of DRB1*0301 (DR3) and B8. In the combined population data, DRB1*0301 showed a stronger association with susceptibility to PSC than both the TNF2 and B8 alleles (OR(combined data)=3.8, p(corr)=10(-6) v OR(combined data)=3.2, p(corr)=10(-5) v OR(combined data )=3.41, p(corr)=10(-4), respectively). CONCLUSIONS: This study identified a significant association between possession of the TNF2 allele, a G-->A substitution at position -308 in the TNF-alpha promoter, and susceptibility to PSC. This association was secondary to the association of PSC with the A1-B8-DRB1*0301-DQA1*0501-DQB1*0201 haplotype. No association was found between the IL-10 -627 promoter polymorphism and PSC.

Adult↗
PubMed1998

Long-term safety and effectiveness of iron-chelation therapy with deferiprone for thalassemia major.

BACKGROUND: Deferiprone is an orally active iron-chelating agent that is being evaluated as a treatment for iron overload in thalassemia major. Studies in an animal model showed that prolonged treatment is associated with a decline in the effectiveness of deferiprone and exacerbation of hepatic fibrosis. METHODS: Hepatic iron stores were determined yearly by chemical analysis of liver-biopsy specimens, magnetic susceptometry, or both. Three hepatopathologists who were unaware of the patients' clinical status, the time at which the specimens were obtained, and the iron content of the specimens examined 72 biopsy specimens from 19 patients treated with deferiprone for more than one year. For comparison, 48 liver-biopsy specimens obtained from 20 patients treated with parenteral deferoxamine for more than one year were similarly reviewed. RESULTS: Of the 19 patients treated with deferiprone, 18 had received the drug continuously for a mean (+/-SE) of 4.6+/-0.3 years. At the final analysis, 7 of the 18 had hepatic iron concentrations of at least 80 micromol per gram of liver, wet weight (the value above which there is an increased risk of cardiac disease and early death in patients with thalassemia major). Of 19 patients in whom multiple biopsies were performed over a period of more than one year, 14 could be evaluated for progression of hepatic fibrosis; of the 20 deferoxamine-treated patients, 12 could be evaluated for progression. Five deferiprone-treated patients had progression of fibrosis, as compared with none of those given deferoxamine (P=0.04). By the life-table method, we estimated that the median time to progression of fibrosis was 3.2 years in deferiprone-treated patients. After adjustment for the initial hepatic iron concentration, the estimated odds of progression of fibrosis increased by a factor of 5.8 (95 percent confidence interval, 1.1 to 29.6) with each additional year of deferiprone treatment. CONCLUSIONS: Deferiprone does not adequately control body iron burden in patients with thalassemia and may worsen hepatic fibrosis.

Adolescent↗
PubMed1998

Granulomas in the livers of humans and Fischer rats associated with the ingestion of mineral hydrocarbons: a comparison.

Ninety-day feeding studies were conducted in Fischer 344 rats using a series of highly refined mineral hydrocarbons which included mineral oils and waxes representative of those used in consumer products and food applications. The series included materials which had been refined by oleum or hydrogenation. The materials tested were representative of the range of carbon chain lengths, molecular weights, and viscosities which are currently in use. Findings revealed the presence of granulomatous lesions in the liver and histiocytosis in the lymph nodes. Some mineral hydrocarbons did not induce any lesions; others induced relatively minor effects; and a low melting point wax induced the largest lesions in both liver and mesenteric lymph nodes, with inflammation and areas of focal necrosis in the livers. The majority of lesions reported were associated with the highest dose levels used. These studies are in contrast to studies in Sprague-Dawley rats in which comparable doses did not induce similar lesions, indicating marked strain variability. Lipogranulomas associated with the ingestion of mineral oil have been reported in humans. The comparative morphology of the lesions seen in the Fischer rat study and those observed in the human are discussed and differences are highlighted. The lesions in the human are not believed to progress to lesions of clinical significance. The pathogenesis of the lesions induced in Fischer rats and in humans is discussed and it is concluded that the majority, if not all of the lesions, in the rats are of no significance for humans. The possibility that a small proportion of cases of granulomatous hepatitis in humans may represent an atypical response to mineral hydrocarbons may need further investigation.

Animal Feed↗
PubMed1997

Clinical outcome of hypogammaglobulinaemic patients following outbreak of acute hepatitis C: 2 year follow up.

In 1994, an outbreak of hepatitis C virus (HCV) infection, genotype 1a, occurred in 30 hypogammaglobulinaemic patients in the UK from one batch of contaminated anti-HCV screened intravenous immunoglobulin. This study aimed to study prospectively the outcome of HCV in hypogammaglobulinaemic patients, and to assess the response to early treatment with interferon-alpha, 6 million units three times weekly for 6 months. Data were collected using standardized questionnaires. Five patients with secondary hypogammaglobulinaemia due to lymphoid malignancy were not treated and all have died of their primary malignancy. Of 25 patients with primary hypogammaglobulinaemia, one resolved HCV infection before treatment, 17 commenced on treatment, and seven declined or treatment was contra-indicated. Thirteen of 17 patients completed therapy and seven (54%) have a sustained response (normal transaminases, negative serum HCV RNA) at 6 and 12 months after treatment. Two of the 12 patients with primary hypogammaglobulinaemia, who were not treated or failed to complete treatment, have cleared the virus. Liver biopsy was performed in patients not clearing HCV and was abnormal in all. Four patients developed liver failure within 2 years, of whom three have died and one has been successfully transplanted. In conclusion, HCV can cause rapid severe liver disease in hypogammaglobulinaemic patients. Early treatment with high-dose interferon-alpha results in a high clearance of HCV.

Acute Disease↗
PubMed1996

Elevation of gamma delta T lymphocytes in peripheral blood and livers of patients with primary sclerosing cholangitis and other autoimmune liver diseases.

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease that is possibly an autoimmune disease. Although gamma delta T cells represent a small proportion of the total T-cell population in healthy individuals, there is evidence to suggest a role for these cells in autoimmunity. Accordingly, the aim of this study was to investigate the population of gamma delta T cells in patients with PSC, compared with other chronic liver diseases. An elevation in the percentage and absolute numbers of gamma delta T cells was found in the peripheral blood of patients with PSC (8.66% and 0.13 x 10(-6)/L [P < .01 and < .05, respectively]) and autoimmune hepatitis (AIH) (8.03% and 0.13 x 10(-6)/L [both P < 0.001]) compared with controls (4.10% and 0.06 x 10(-6)/L). We also found an elevation in the percentage and absolute numbers of gamma delta T cells in the portal areas of patients with PSC (10.55% and 4.33 [P < .001 and < .001, respectively]), AIH (7.16% and 4.55 [P = .001 and < .001, respectively]), and primary biliary cirrhosis (PBC) (5.57% and 3.49 [P = .008 and < .001, respectively]) when compared with controls (2.23% and 0.81). These findings suggest a role for gamma delta T cells in the mechanism of immune damage in autoimmune liver diseases.

Aged↗
PubMed1996

Outbreak of acute hepatitis C following the use of anti-hepatitis C virus--screened intravenous immunoglobulin therapy.

BACKGROUND & AIMS: Hepatitis C virus (HCV) infection has been associated with intravenous (IV) immunoglobulin (Ig), and plasma donations used to prepare IV Ig are now screened to prevent transmission. Thirty-six patients from the United Kingdom received infusions from a batch of anti-HCV antibody-screened intravenous Ig (Gammagard; Baxter Healthcare Ltd., Thetford, Norfolk, England) that was associated with reports of acute hepatitis C outbreak in Europe. The aim of this study was to document the epidemiology of this outbreak. METHODS: Forty-six patients from the United Kingdom treated with Gammagard (34 exposed and 12 unexposed to the batch) returned epidemiological questionnaires. RESULTS: Eighty-two percent of the exposed patients (28 of 34) became positive for HCV RNA. Eighteen percent of the patients (6 of 34) who had infusions with this batch tested negative for HCV RNA, but 2 of the patients had abnormal liver function and subsequently seroconverted to anti-HCV antibody positive. Twenty-seven percent of the patients (9 of 34) developed jaundice, and 79% (27 of 34) had abnormal liver transferase levels. Virus isolates (n=21), including an isolate from the implicated batch, were genotype 1a and virtually identical by sequence analysis of the NS5 region, consistent with transmission from a single source. CONCLUSIONS: Hepatitis C infection can be transmitted by anti-HCV-screened IV Ig. Careful documentation of IV Ig batch numbers and regular biochemical monitoring is recommended for all IV Ig recipients.

Acute Disease↗
PubMed1996

Absence of antineutrophil cytoplasmic antibodies in relatives of UK patients with primary sclerosing cholangitis and ulcerative colitis.

OBJECTIVE: Perinuclear antineutrophil cytoplasmic antibodies (ANCA) have been reported in patients and relatives of patients with ulcerative colitis and primary sclerosing cholangitis, suggesting that ANCA may be a genetic marker of disease susceptibility. The reported frequency of ANCA in relatives has varied greatly, between 0 and 30%. We therefore studied the prevalence of ANCA in unaffected first-degree relatives of British patients with primary sclerosing cholangitis and ulcerative colitis. DESIGN: Thirty-six patients with ulcerative colitis, 33 with primary sclerosing cholangitis and 187 relatives were studied. Ninety-seven relatives were from the primary sclerosing cholangitis proband and 90 were from the ulcerative colitis proband. As an environmental control, 32 spouses were included: 14 from the primary sclerosing cholangitis group and 18 from the ulcerative colitis group. Eighteen healthy volunteers were additional controls. METHODS: ANCA was detected using immunoalkaline phosphatase method. RESULTS: Only 3 of 97 (3%) of the primary sclerosing cholangitis proband relatives had ANCA. One of these had ulcerative colitis, one had rheumatoid arthritis and the third systemic lupus erythematosus. Both rheumatoid arthritis and system lupus erythematosus are known to exhibit ANCA. All other sera were negative. CONCLUSION: ANCA was found only in patients with primary cholangitis and ulcerative colitis and not in their healthy first-degree relatives. ANCA is therefore not a genetic marker for increased disease susceptibility to primary sclerosing cholangitis or ulcerative colitis in the British population.

Adult↗
PubMed1996

Importance of antineutrophil cytoplasmic antibodies in primary sclerosing cholangitis and ulcerative colitis: prevalence, titre, and IgG subclass.

Antineutrophil cytoplasmic antibodies (ANCA) have been reported in up to 87% of patients with primary sclerosing cholangitis with or without ulcerative colitis (PSC +/- UC) and in 68% of those with UC only. Compared with other liver and diarrhoeal diseases, ANCA have high specificity for PSC (+/- UC) and UC only. This study aimed to determine the prevalence and significance of ANCA in these two diseases and whether the ANCA titre or IgG subclass, or both, could distinguish between PSC + UC and UC only. Subjects included 63 patients with PSC, 85 with UC, 17 with coeliac disease, and 10 with dermatitis herpeteformis and 36 normal subjects. ANCA was detected using the immunoalkaline phosphatase method. The IgG subclass of ANCA was determined in 27 PSC + UC and 30 UC only patients using a panel of mouse monoclonal antibodies specific for the IgG subclasses. At a serum dilution of 1:5, ANCA had a diagnostic sensitivity of 65% for all PSC and 45% for UC only. For PSC + UC the sensitivity was 70% at 1:5 (p = 0.004 v UC only). At 1:50, the sensitivity values were 54% and 25% respectively for PSC + UC and UC only (p = 0.0006). In PSC, ANCA positivity was significantly associated with extensive involvement of the biliary tree but not with other clinical parameters. In UC only, the median disease duration was significantly greater in ANCA positive patients. The PSC + UC ANCA showed increased IgG3 compared with UC only ANCA (p < 0.05), together with increased IgG2 and IgG4 (p = NS). ANCA is a diagnostic marker in PSC and UC. While the higher titres and different IgG subclass distribution of ANCA in PSC + UC patients compared with those with UC only may reflect differences in underlying immune regulation, determination of the ANCA titre and IgG subclass is unlikely to have a role in distinguishing between PSC + UC and UC only ANCA. Future identification of the antigen(s) for ANCA should allow the development of a more sensitive and specific test for the diagnosis of these two conditions and also determine if ANCA is associated with UC or PSC.

Adult↗
PubMed1996

Biliary expression of heat shock protein: a non-specific feature of chronic cholestatic liver diseases.

AIM: To analyse the expression of heat shock protein (HSP) 60 in biliary epithelium in auto-immune liver conditions and also in chronic cholestatic and other liver diseases. METHODS: Hepatic expression of HSP-60 in frozen liver biopsy specimens from patients with primary sclerosing cholangitis (PSC), primary biliary cirrhosis (PBC), auto-immune hepatitis (AIH), obstructive jaundice (LDO), alcoholic liver disease (ALD), and from normal controls was studied by immunohistochemistry using the APAAP technique and confocal laser scanning microscopy. RESULTS: Increased expression of HSP-60 was demonstrated in the biliary epithelium of patients with PBC, LDO and, to a lesser extent, with PSC. Focal, weaker, biliary epithelial expression of HSP-60 was observed in AIH, ALD and normal liver tissue. Increased expression was also seen on Kupffer cells in LDO and in hepatocytes in areas of piecemeal necrosis in AIH. CONCLUSION: Enhanced biliary expression of HSP-60 is a common feature of chronic biliary disease irrespective of aetiology and is not specific to auto-immune diseases.

Autoimmune Diseases↗
PubMed1996

Prevalence and diagnostic role of antineutrophil cytoplasmic antibodies in inflammatory bowel disease.

BACKGROUND: Antineutrophil cytoplasmic antibodies (ANCA) are of proven diagnostic value in a variety of vasculitides, where they are also thought to play a pathogenic role. ANCA has also been detected in the serum of patients with idiopathic inflammatory bowel disease (IBD), both ulcerative colitis (UC) and Crohn's disease (CD), and primary sclerosing cholangitis (PSC) with or without concomitant IBD. Although the prevalence in PSC and UC is reported to be up to 85%, a much lower prevalence of around 10-20% has been reported in CD. AIM: To determine ANCA prevalence in a group of British patients with IBD and evaluate their use as a serological marker to distinguish between UC and CD. METHODS: A total of 99 UC-only patients (44 males, median age 50) and 41 CD patients (11 males, median age 47) were tested for ANCA using an alkaline phosphatase technique at a 1:5 serum dilution. Controls were other diarrhoeal diseases including 17 coeliac disease (4 males, median age 41), 23 irritable bowel syndrome (5 males, median age 42), 5 infectious colitis (2 male, median age 64) and 36 healthy volunteers (13 males, median age 43). RESULTS: ANCA was detected in 42/99 (42.4%) UC patients but in only 2/41 (5%) CD (P < 0.0001). All ANCA were perinuclear in distribution. No ANCA was detected in the control sera. The sensitivity of the test for the diagnosis of UC was 42% with a specificity of 98%. In patients with UC, no association was found between presence of ANCA and age, sex, disease extent, treatment or activity. However, ANCA-positive UC patients had longer median duration of disease (50 months vs. 29 months, P = 0.037). Both CD ANCA-positive patients had colonic involvement, but one also had ileal disease. Both had inactive disease and one was on mesalazine. CONCLUSIONS: ANCA is highly specific for UC and may be a helpful diagnostic test in distinguishing UC from CD and other diarrhoeal illnesses. Although ANCA positivity may reflect disease heterogeneity within UC, no association with clinical features or treatment of UC was demonstrated and it is therefore unlikely to play a pathogenic role. The correlation with disease duration needs further investigation.

Adult↗
PubMed1995

High prevalence of pancreatic islet amyloid in patients with end-stage renal failure on dialysis treatment.

Islet amyloid polypeptide (IAPP) is the main proteinaceous component of pancreatic islet amyloid, which is a characteristic feature of type 2 diabetes. The factors responsible for amyloid deposition are unclear. Patients with end-stage renal failure (ESRF) on dialysis treatment have increased insulin resistance which is associated with hypersecretion of beta-cell products. Furthermore, elevated concentrations of circulating IAPP are found in these patients due to reduced renal clearance of IAPP. To determine the prevalence of islet amyloid in this group of patients, pancreas was examined from 23 non-diabetic [aged 62 (29-79) years, median and range] and four type 2 diabetic [aged 67 (56-72) years] patients with ESRF on dialysis treatment. Pancreatic specimens from 30 non-diabetic control subjects [aged 67.5 (56-86) years] and 14 type 2 diabetic subjects without renal disease [aged 69 (48-86) years] were used as control groups. Islet amyloid was present in all type 2 diabetic patients with ESRF and in 12 out of 14 type 2 diabetic control subjects (86 per cent). Amyloid deposits were found in 8 out of 23 non-diabetic patients with ESRF (35 per cent), which was a higher prevalence than that found in non-diabetic control subjects (3 per cent) (P < 0.01). This may be related to undiagnosed (pre)diabetes. Elevated secretion rates of IAPP due to insulin resistance and high circulating IAPP concentrations as a result of severely reduced renal clearance of IAPP will cause high pericellular concentrations of IAPP. This condition is likely to enhance amyloid fibril formation in pancreatic islets similar to that observed in type 2 diabetes.

Adult↗