Mucosal-associated invariant T cell alterations during the development of human type 1 diabetes.

AIMS/HYPOTHESIS: Mucosal-associated invariant T (MAIT) cells are innate-like T cells that recognise derivatives of bacterial riboflavin metabolites presented by MHC-Ib-related protein 1 (MR1) molecules and are important effector cells for mucosal immunity. Their development can be influenced by the intestinal microbiome. Since the development of type 1 diabetes has been associated with changes in the gut microbiome, this can be hypothesised to lead to alterations in circulating MAIT cells. Accordingly, peripheral blood MAIT cell alterations have been reported previously in patients with type 1 diabetes. However, a comprehensive analysis of the frequency and phenotype of circulating MAIT cells at different stages of type 1 diabetes progression is currently lacking. METHODS: We analysed the frequency, phenotype and functionality of peripheral blood MAIT cells, as well as γδ T cells, invariant natural killer T (iNKT) cells and natural killer (NK) cells with flow cytometry in a cross-sectional paediatric cohort (aged 2-15) consisting of 51 children with newly diagnosed type 1 diabetes, 27 autoantibody-positive (AAb+) at-risk children, and 113 healthy control children of similar age and HLA class II background. The frequency of MAIT cells was also assessed in a separate cross-sectional adult cohort (aged 19-39) of 33 adults with established type 1 diabetes and 37 healthy individuals of similar age. RESULTS: Children with newly diagnosed type 1 diabetes displayed a proportional increase of CD8-CD27- MAIT cells compared with healthy control children (median 4.6% vs 3.1% of MAIT cells, respectively, p = 0.004), which was associated with reduced expression of C-C chemokine receptor (CCR)5 (median 90.0% vs 94.3% of MAIT cells, p = 0.02) and ß7 integrin (median 73.5% vs 81.7% of MAIT cells, p = 0.004), as well as decreased production of IFN-γ (median 57.1% vs 69.3% of MAIT cells, p = 0.04) by the MAIT cells. The frequency of MAIT cells was also decreased in AAb+ children who later progressed to type 1 diabetes compared with healthy control children (median 0.44% vs 0.96% of CD3+ T cells, p = 0.04), as well as in adult patients with a short duration of type 1 diabetes (less than 6 years after diagnosis) compared with control individuals (median 0.87% vs 2.19% of CD3+ T cells, p = 0.007). No alterations in γδ T cell, iNKT cell or NK cell frequencies were observed in children with type 1 diabetes or in AAb+ children, with the exception of an increased frequency of IL-17A+ γδ T cells in children with newly diagnosed diabetes compared with healthy control children (median 1.58% vs 1.09% of γδ T cells, p = 0.002). CONCLUSIONS/INTERPRETATION: Changes in the frequency and phenotype of circulating MAIT cells were detectable before, at the onset and after diagnosis of type 1 diabetes in cross-sectional cohorts. Our results suggest a possible temporal association between peripheral blood MAIT cell alterations and the clinical onset of type 1 diabetes. Graphical abstract.

Effector T Cell Resistance to Suppression and STAT3 Signaling during the Development of Human Type 1 Diabetes.

Dysregulation of regulatory T cell (Treg)-mediated suppression and, in particular, resistance of CD4+ effector T cells (Teffs) to suppression have been implicated in the pathogenesis of human type 1 diabetes (T1D). However, the mechanistic basis behind this resistance and the time frame during which it develops in relation to the onset of clinical T1D remain unclear. In this study, we analyzed the capacity of peripheral blood Teffs isolated both from patients with T1D and from prediabetic at-risk subjects positive for multiple diabetes-associated autoantibodies (AAb+) to be suppressed by Tregs. Because STAT3 activation through IL-6 has previously been implicated in mediating Teff resistance, we also investigated the surface expression of IL-6R as well as IL-6- and TCR-mediated phosphorylation of STAT3 in T cells from our study subjects. Teff resistance to suppression was observed both in patients with newly diagnosed and long-standing T1D but not in AAb+ subjects and was shown to be STAT3 dependent. No alterations in IL-6R expression or IL-6-mediated STAT3 activation were observed in T cells from patients with T1D or AAb+ subjects. However, faster STAT3 activation after TCR stimulation without concomitant increase in IL-6 expression was observed in T cells from patients with T1D. These experiments suggest that Teff resistance in T1D patients is STAT3 dependent but not directly linked with the capacity of Teffs to produce or respond to IL-6. In conclusion, Teff resistance to Treg-mediated suppression is likely a feature of disease progression in human T1D and can potentially be targeted by immune therapies that block STAT3 activation.

Circulating CXCR5-PD-1hi peripheral T helper cells are associated with progression to type 1 diabetes.

AIMS/HYPOTHESIS: Type 1 diabetes is preceded by a period of asymptomatic autoimmunity characterised by positivity for islet autoantibodies. Therefore, T helper cell responses that induce B cell activation are likely to play a critical role in the disease process. Here, we aimed to evaluate the role of a recently described subset, C-X-C motif chemokine receptor type 5-negative, programmed cell death protein 1-positive (CXCR5-PD-1hi) peripheral T helper (Tph) cells, in human type 1 diabetes. METHODS: The phenotype of blood CXCR5-PD-1hi CD4+ T cells was analysed by multicolour flow cytometry. The frequencies of circulating CXCR5-PD-1hi T cells were analysed in a cohort of 44 children with newly diagnosed type 1 diabetes, 40 autoantibody-positive (AAb+) at-risk children and 84 autoantibody-negative healthy control children, and the findings were replicated in a separate cohort of 15 children with newly diagnosed type 1 diabetes and 15 healthy control children. RESULTS: Circulating CXCR5-PD-1hi Tph cells share several features associated with B cell helper function with circulating CXCR5+PD-1hi follicular T helper (Tfh) cells. Moreover, the frequency of circulating Tph cells was increased in children with newly diagnosed type 1 diabetes, especially in those who are positive for multiple autoantibodies. Importantly, circulating Tph cells were also increased in autoantibody-positive at-risk children who later progressed to type 1 diabetes. CONCLUSIONS/INTERPRETATION: Our results demonstrate that circulating CXCR5-PD-1hi Tph cells are associated with progression to clinical type 1 diabetes. Consequently, Tph cells could have potential both as a biomarker of disease progression and as a target for immunotherapy in type 1 diabetes.

Human rhinoviruses in INDIS-study material-evidence for recovery of viable rhinovirus from fecal specimens.

The significance of human rhinoviruses (HRV) as prevailing respiratory pathogens has sharpened during the recent years followed by implementation of molecular methods in detection. Rhinoviruses are detected exceedingly in hospitalized cases of respiratory infection with varying severity, in addition to being frequent in cases of common cold. The aim of this study was to evaluate occurrence of HRV in a prospective study material. The prospective INDIS material comprises nasopharyngeal (N=429) and fecal (N=425) specimens from children under 11 years of age collected during any clinical infection. Validated real-time RT-PCR assays were applied for the detection of HRV. HRV were detected numerously not only in the nasopharyngeal specimens, but a myriad also in fecal specimens, 236 (55.0%) and 149 (35.1%), respectively, fecal findings actually beyond anticipation. A total of 13 of HRV-positive fecal specimens were selected for genetic typing in the VP4/VP2 coding region. HRV-A strains were detected in seven specimens: HRV-A9, -A10, -A24, -A49, -A56 and -A82. HRV-B-strains were detected three times: HRV-B42 and -B79, and HRV-C twice: HRV-C12 and HRV-Cpat4. HRV-B42 also showed cytopathic effect in cell culture, confirmed by real-time RT-PCR and VP4/VP2 sequencing, suggesting presence of viable HRV in fecal specimens.

Virus infections among young children--the first year of the INDIS study.

The frequencies of early childhood infections were studied in healthy children with increased genetic risk for type 1 diabetes participating in the ongoing prospective high intensive infection follow-up Study, INDIS, started in 2009 in Turku, Finland. Here the results obtained from 160 stool to 160 nasal swab specimens collected in parallel at times of infectious symptoms in 2009-2010 from 45 children at the age of 24 months or younger are reported. The specimens were analyzed for enteric (human enterovirus, norovirus, rotavirus, sapovirus, astrovirus) and respiratory RNA viruses (human enterovirus and rhinovirus) common in early childhood, respectively, using highly validated virus-specific real-time PCR methods. According to the results 96% of the children had at least one virus infection during the study period and one or several viral agents were detected in 76% of sample sets. The most prevalent viral agents were human rhinovirus, enterovirus, parechovirus, and norovirus (genotype GII) with positive specimens 57.5%, 28.8%, 19.4%, and 6.9%, respectively. Other intestinal viruses were found in less than 2% of stool specimens. Single infections covered 40.0% of the specimens while multiple infections with two or more infectious agents were detected in 36.3% of specimens and altogether 11 combinations of viruses were included in the mixed infections. Although human enterovirus is known to be a frequent finding in stool specimens, especially during early childhood, it was found in this study more frequently in nasal swab specimens. Whether this is true, more general, in countries with the high hygiene level remains to be shown.

DNA methylation differences within INS, PTPN22 and IL2RA promoters in lymphocyte subsets in children with type 1 diabetes and controls.

We elucidated the effect of four known T1D-susceptibility associated single nucleotide polymorphism (SNP) markers in three genes (rs12722495 and rs2104286 in IL2RA, rs689 in INS and rs2476601 in PTPN22) on CpG site methylation of their proximal promoters in different lymphocyte subsets using pyrosequencing. The study cohort comprised 25 children with newly diagnosed T1D and 25 matched healthy controls. The rs689 SNP was associated with methylation at four CpG sites in INS promoter: -234, -206, -102 and -69. At all four CpG sites, the susceptibility genotype AA was associated with a higher methylation level compared to the other genotypes. We also found an association between rs12722495 and methylation at CpG sites -373 and -356 in IL2RA promoter in B cells, where the risk genotype AA was associated with lower methylation level compared to the AG genotype. The other SNPs analyzed did not demonstrate significant associations with CpG site methylation in the examined genes. Additionally, we compared the methylation between children with T1D and controls, and found statistically significant methylation differences at CpG -135 in INS in CD8+ T cells (p = 0.034), where T1D patients had a slightly higher methylation compared to controls (87.3 ± 7.2 vs. 78.8 ± 8.9). At the other CpG sites analyzed, the methylation was similar. Our results not only confirm the association between INS methylation and rs689 discovered in earlier studies but also report this association in sorted immune cells. We also report an association between rs12722495 and IL2RA promoter methylation in B cells. These results suggest that at least part of the genetic effect of rs689 and rs12722495 on T1D pathogenesis may be conveyed by DNA methylation.

Evaluation of plasma IL-21 as a potential biomarker for type 1 diabetes progression.

IL-21 is a multifunctional cytokine linked with the pathophysiology of several autoimmune diseases, including type 1 diabetes. In this study, our aim was to examine plasma IL-21 levels in individuals at different stages of type 1 diabetes progression. We measured plasma IL-21 levels, as well as levels of other key pro-inflammatory cytokines (IL-17A, TNF-α and IL-6), from 37 adults with established type 1 diabetes and 46 healthy age-matched adult controls, as well as from 53 children with newly diagnosed type 1 diabetes, 48 at-risk children positive for type 1 diabetes-associated autoantibodies and 123 healthy age-matched pediatric controls using the ultrasensitive Quanterix SiMoA technology. Adults with established type 1 diabetes had higher plasma IL-21 levels compared to healthy controls. However, the plasma IL-21 levels showed no statistically significant correlation with clinical variables, such as BMI, C-peptide, HbA1c, or hsCRP levels, evaluated in parallel. In children, plasma IL-21 levels were almost ten times higher than in adults. However, no significant differences in plasma IL-21 levels were detected between healthy children, autoantibody-positive at-risk children, and children with newly diagnosed type 1 diabetes. In conclusion, plasma IL-21 levels in adults with established type 1 diabetes were increased, which may be associated with autoimmunity. The physiologically high plasma IL-21 levels in children may, however, reduce the potential of IL-21 as a biomarker for autoimmunity in pediatric subjects.

Exploring the transcriptomic variation caused by the Finnish founder mutation of lysinuric protein intolerance (LPI).

Lysinuric protein intolerance (LPI) is an autosomal recessive disorder caused by mutations in cationic amino acid transporter gene SLC7A7. Although all Finnish patients share the same homozygous mutation, their clinical manifestations vary greatly. The symptoms range from failure to thrive, protein aversion, anemia and hyperammonaemia, to immunological abnormalities, nephropathy and pulmonary alveolar proteinosis. To unravel the molecular mechanisms behind those symptoms not explained directly by the primary mutation, gene expression profiles of LPI patients were studied using genome-wide microarray technology. As a result, we discovered 926 differentially-expressed genes, including cationic and neutral amino acid transporters. The functional annotation analysis revealed a significant accumulation of such biological processes as inflammatory response, immune system processes and apoptosis. We conclude that changes in the expression of genes other than SLC7A7 may be linked to the various symptoms of LPI, indicating a complex interplay between amino acid transporters and various cellular processes.

[Is it necessary to monitor the cognitive development of a child having diabetes?]. / Onko tarpeen seurata diabetesta sairastavan lapsen kognitiivista kehitystä?

Metabolic disorders associated with type 1 diabetes may affect brain function both momentarily during excessively low or high blood glucose levels and by causing permanent alterations. These may have an influence on the cognitive development of a child who has been diagnosed with diabetes at a very young age. Significant learning problems are rare, but their early detection and appropriate support are part of good clinical practice. Good glucose control protects also the brain.

Combined hyperlipidemia in patients with lysinuric protein intolerance.

BACKGROUND AND AIMS: Lysinuric protein intolerance (LPI) is an autosomal recessive disorder characterized by defective transport of cationic amino acids lysine, arginine, and ornithine. Low plasma concentrations of arginine and ornithine lead to impaired urea cycle function and, subsequently, decreased protein tolerance. Patients often develop natural aversion to protein-rich foods, which may predispose them to nutritional problems. The objective of this retrospective study was to investigate lipid values and efficacy of lipid-lowering therapy in patients with LPI. METHODS AND RESULTS: Serum total and high-density-lipoprotein (HDL)-cholesterol and triglyceride concentrations were analyzed in 39 Finnish LPI patients (14 males) aged 3-64 years. Dietary intakes were analyzed from food records. Mean [standard deviation (SD)] serum and HDL-cholesterol and triglyceride concentrations were 7.16 (2.13) mmol/l, 1.21 (0.58) mmol/l, and 4.0 (2.4) mmol/l, respectively. Patients with renal dysfunction had marginally higher total cholesterol and significantly higher triglyceride concentration than patients without renal impairment. Twenty-two patients were started on 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (atorvastatin or simvastatin). After 6 months, serum cholesterol and triglyceride concentrations had decreased by 32% (p < 0.001), whereas HDL-cholesterol had increased by 13% (p = 0.016). CONCLUSION: Serum cholesterol and triglyceride values are markedly elevated in LPI patients. Although the mechanism of combined hyperlipidemia remains unknown and is not explained by fat consumption, hyperlipidemia is clearly progressive with age, suggesting that starting statin therapy early is probably beneficial. Statins are well-tolerated and efficacious in LPI.

[Insulin-induced lipoatrophy in children]. / InsuLiinihoidon lapsille aiheuttama lipoatrofia.

Insulin-induced lipoatrophy is a rare but serious complication of insulin treatment. Its incidence decreased during 1970' and 1980's, but several reports of this phenomenon have again recently been published. Traditional treatment options have included injecting insulin or pump cannula to the area surrounding the lipoatrophy or changing the insulin type or preparation. In this report we present 4 children who developed severe lipoatrophy during insulin pump treatment. Changing injection sites did not help but lipoatrophy disappeared in one patient after changing the insulin preparation. In the three other patients no new atrophy sites have appeared after change in insulin preparation or simultaneous treatment with local pimecrolimus or sodium cromoglicate.

Nasal insulin to prevent type 1 diabetes in children with HLA genotypes and autoantibodies conferring increased risk of disease: a double-blind, randomised controlled trial.

BACKGROUND: In mouse models of diabetes, prophylactic administration of insulin reduced incidence of the disease. We investigated whether administration of nasal insulin decreased the incidence of type 1 diabetes, in children with HLA genotypes and autoantibodies increasing the risk of the disease. METHODS: At three university hospitals in Turku, Oulu, and Tampere (Finland), we analysed cord blood samples of 116 720 consecutively born infants, and 3430 of their siblings, for the HLA-DQB1 susceptibility alleles for type 1 diabetes. 17 397 infants and 1613 siblings had increased genetic risk, of whom 11 225 and 1574, respectively, consented to screening of diabetes-associated autoantibodies at every 3-12 months. In a double-blind trial, we randomly assigned 224 infants and 40 siblings positive for two or more autoantibodies, in consecutive samples, to receive short-acting human insulin (1 unit/kg; n=115 and n=22) or placebo (n=109 and n=18) once a day intranasally. We used a restricted randomisation, stratified by site, with permuted blocks of size two. Primary endpoint was diagnosis of diabetes. Analysis was by intention to treat. The study was terminated early because insulin had no beneficial effect. This study is registered with ClinicalTrials.gov, number NCT00223613. FINDINGS: Median duration of the intervention was 1.8 years (range 0-9.7). Diabetes was diagnosed in 49 index children randomised to receive insulin, and in 47 randomised to placebo (hazard ratio [HR] 1.14; 95% CI 0.73-1.77). 42 and 38 of these children, respectively, continued treatment until diagnosis, with yearly rates of diabetes onset of 16.8% (95% CI 11.7-21.9) and 15.3% (10.5-20.2). Seven siblings were diagnosed with diabetes in the insulin group, versus six in the placebo group (HR 1.93; 0.56-6.77). In all randomised children, diabetes was diagnosed in 56 in the insulin group, and 53 in the placebo group (HR 0.98; 0.67-1.43, p=0.91). INTERPRETATION: In children with HLA-conferred susceptibility to diabetes, administration of nasal insulin, started soon after detection of autoantibodies, could not be shown to prevent or delay type 1 diabetes.

[Phenylketonuria]. / Fenyyliketonuria.

Owing to our special genetic heritage, phenylketonuria is very rare in Finland, but the situation will change as the number of immigrants from populations with a larger incidence increases. In persons with this disorder, the enzyme phenylalanine hydroxylase, which metabolizes phenylalanine to tyrosine, is not functioning normally, leading to the accumulation phenylalanine within the body. High levels of phenylalanine are toxic to the central nervous system. A newborn affected with phenylketonuria is asymptomatic but will rapidly become disabled without therapy. The leading principle of the therapy is careful limitation of phenylalanine intake.

The psychosocial self-efficacy in adolescents with type 1 diabetes.

AIM: To analyse psychosocial self-efficacy in adolescents with type 1 diabetes, evaluate associations between self-efficacy and metabolic control and background variables and determine psychometric properties of the Finnish Diabetes Empowerment Scale (Fin-DES-28). DESIGN: A descriptive correlational survey. METHODS: The data were collected with the Finnish Diabetes Empowerment Scale from 13-16-year-old adolescents with type 1 diabetes (N = 189, 34%) in one university hospital district area in 2014. RESULTS: The level of psychosocial self-efficacy was quite good. The highest scores were in managing the psychosocial aspects of diabetes, followed by assessing dissatisfaction and readiness to change and setting and achieving diabetes goals. The self-efficacy did not correlate with metabolic control or background variables. A positive association was found between self-efficacy and understanding of diabetes and its treatment, adjustment of diabetes to life and the relationship with the doctor and the nurse. The internal consistency of the Finnish Diabetes Empowerment Scale was adequate. The low response rate limits generalization.

FOXP3+ Regulatory T Cell Compartment Is Altered in Children With Newly Diagnosed Type 1 Diabetes but Not in Autoantibody-Positive at-Risk Children.

The dysfunction of FOXP3-positive regulatory T cells (Tregs) plays a key role in the pathogenesis of autoimmune diseases, including type 1 diabetes (T1D). However, previous studies analyzing the peripheral blood Treg compartment in patients with T1D have yielded partially conflicting results. Moreover, the phenotypic complexity of peripheral blood Tregs during the development of human T1D has not been comprehensively analyzed. Here, we used multi-color flow cytometry to analyze the frequency of distinct Treg subsets in blood samples from a large cohort comprising of 74 children with newly diagnosed T1D, 76 autoantibody-positive children at-risk for T1D and 180 age- and HLA-matched control children. The frequency of CD4+CD25+CD127lowFOXP3+ Tregs was higher in children with T1D compared to control children, and this change was attributable to a higher proportion of naïve Tregs in these subjects. Further longitudinal analyses demonstrated that the increase in Treg frequency correlated with disease onset. The frequencies of the minor subsets of CD25+FOXP3low memory Tregs as well as CD25lowCD127lowFOXP3+ Tregs were also increased in children with T1D. Moreover, the ratio of CCR6-CXCR3+ and CCR6+CXCR3- memory Tregs was altered and the frequency of proliferating Ki67-positive and IFN-γ producing memory Tregs was decreased in children with T1D. The frequency of CXCR5+FOXP3+ circulating follicular T regulatory cells was not altered in children with T1D. Importantly, none of the alterations observed in children with T1D were observed in autoantibody-positive at-risk children. In conclusion, our study reveals multiple alterations in the peripheral blood Treg compartment at the diagnosis of T1D that appear not to be features of early islet autoimmunity.

Impact of repeated dietary counseling between infancy and 14 years of age on dietary intakes and serum lipids and lipoproteins: the STRIP study.

BACKGROUND: Atherosclerosis development might be delayed or prevented by dietary measures. The aims of the present study were to evaluate the effect of low-saturated-fat, low-cholesterol dietary counseling on fat intakes, growth, serum cholesterol values, and pubertal development in children and adolescents. METHODS AND RESULTS: In the randomized prospective Special Turku Coronary Risk Factor Intervention Project (STRIP), a low-saturated-fat, low-cholesterol diet was introduced to intervention infants (n=540) at 7 months of age, and control children (n=522) received an unrestricted diet. Dietary intakes, serum cholesterol values, somatic growth, and development were followed up throughout childhood and adolescence. Saturated fat intakes, serum total cholesterol, and low-density lipoprotein cholesterol values were lower (P<0.001) in the intervention than in control children during the 14 years, whereas high-density lipoprotein cholesterol values in the 2 study groups showed no difference. Boys had lower total and low-density lipoprotein cholesterol concentrations than girls throughout childhood (P<0.001), and the intervention effect on serum cholesterol concentration was larger in boys than girls. The 2 study groups showed no difference in growth, body mass index, pubertal development, or age at menarche (median, 13.0 and 12.8 years in the intervention and control girls, respectively; P=0.52). The cholesterol values decreased as puberty progressed. Mean concentrations of total and high-density lipoprotein cholesterol decreased from approximately 4.5 and approximately 1.4 mmol/L, respectively, in Tanner stage 1 (prepubertal) boys to approximately 3.9 and approximately 1.1 mmol/L in Tanner stage 4 (late pubertal) boys. CONCLUSIONS: Repeated dietary counseling remains effective in decreasing saturated fat and cholesterol intake and serum cholesterol values at least until 14 years of age. Puberty markedly influences serum cholesterol concentrations.

Carnitine deficiency and L-carnitine supplementation in lysinuric protein intolerance.

The aim of the study was to investigate the prevalence and mechanisms of development of carnitine deficiency in patients with lysinuric protein intolerance (LPI). In our cohort of 37 Finnish patients with LPI, 8 (8-52 years of age) have been diagnosed with hypocarnitinemia. Their free and total serum carnitine levels, acyl carnitine profiles, renal function, diet, and medication were compared with the data from 8 age- and sex-matched patients with LPI not treated with carnitine supplementation. In patients with LPI, hypocarnitinemia was strongly associated with female sex, renal insufficiency, and the use of ammonia-scavenging drugs. Of the 8 hypocarnitinemic patients, 3 complained of muscle weakness, and their symptoms disappeared during carnitine supplementation. Oral lysine supplementation did not correct hypocarnitinemia in our patients. The patients with LPI are at considerable risk for carnitine deficiency. Supplementation of hypocarnitinemic LPI patients with oral L-carnitine improved serum total carnitine values, but the ratio of free and total carnitine remained subnormal in all supplemented patients except one. Furthermore, decreased ratio of free and total serum carnitine was common even in LPI patients with normal total serum carnitine concentration.

Noninvasive diagnosis of focal hyperinsulinism of infancy with [18F]-DOPA positron emission tomography.

Congenital hyperinsulinism of infancy (CHI) is characterized by severe hypoglycemia due to dysregulated insulin secretion, associated with either focal or diffuse pathology of the endocrine pancreas. The focal condition is caused by a paternally inherited mutation in one of the genes encoding the subunits of the beta-cell ATP-sensitive potassium channel (SUR1/ABCC8 or Kir6.2/KCNJ11) and somatic loss of maternal 11p15 alleles within the affected area. Until now, preoperative diagnostics have relied on technically demanding and invasive catheterization techniques. We evaluated the utility of fluorine-18 l-3,4-dihydroxyphenylalanine ([(18)F]-DOPA) positron emission tomography (PET) to identify focal pancreatic lesions in 14 CHI patients, 11 of which carried mutations in the ABCC8 gene (age 1-42 months). To reduce bias in PET image interpretation, quantitative means for evaluation of pancreatic [(18)F]-DOPA uptake were established. Five patients had a visually apparent focal accumulation of [(18)F]-DOPA and standardized uptake value (SUV) >50% higher (mean 1.8-fold) than the maximum SUV of the unaffected part of the pancreas. When these patients were operated on, a focus of 4-5 x 5-8 mm matching with the PET scan was found, and all were normoglycemic after resection of the focus. The remaining nine patients had diffuse accumulation of [(18)F]-DOPA in the pancreas (SUV ratio <1.5). Diffuse histology was verified in four of these, and pancreatic catheterization was consistent with diffuse pathology in four cases. In conclusion, [(18)F]-DOPA PET is a promising noninvasive method for the identification and localization of the focal form of CHI.

Nephropathy advancing to end-stage renal disease: a novel complication of lysinuric protein intolerance.

OBJECTIVE: To analyze systemically the prevalence of renal involvement in a cohort of Finnish patients with lysinuric protein intolerance (LPI) and to describe the course and outcome of end-stage renal disease in 4 patients. STUDY DESIGN: The clinical information in a cohort of 39 Finnish patients with LPI was analyzed retrospectively. RESULTS: Proteinuria was observed in 74% of the patients and hematuria was observed in 38% of the patients during follow-up. Elevated blood pressure was diagnosed in 36% of the patients. Mean serum creatinine concentration increased in 38% of the patients, and cystatin C concentration increased in 59% of the patients. Four patients required dialysis, and severe anemia with poor response to erythropoietin and iron supplementation also developed in these patients. CONCLUSIONS: Our findings suggest that renal function of patients with LPI needs to be carefully monitored, and hypertension and hyperlipidemia should be treated effectively. Special attention also should be paid to the prevention of osteoporosis and carnitine deficiency in the patients with end-stage renal disease associated with LPI. The primary disease does not prohibit treatment by dialysis and renal transplantation.

Long-term oral lysine supplementation in lysinuric protein intolerance.

In lysinuric protein intolerance (LPI), defective transport of cationic amino acids at the basolateral membrane of the polar epithelial cells in the intestine and renal tubules leads to decreased intestinal absorption and excessive renal loss of lysine, arginine, and ornithine. Citrulline supplementation partially restores the function of the urea cycle that is impaired by deficiency of arginine and ornithine, but does not correct the chronic lysine deficiency. Previous attempts to supplement lysine orally have been hindered by profuse diarrhea, probably caused by excess lysine remaining unabsorbed in the gut. However, individually adjusted minute doses of L-lysine hydrochloride at mealtimes are tolerated well, but the long-term benefits of this therapy remain unknown. The aim of the study was to investigate the long-term benefits and possible adverse effects of oral lysine supplementation in patients with LPI. Supplementation of meals with low doses of oral lysine improved fasting plasma lysine concentrations in 27 Finnish patients with LPI without causing hyperammonemia or other recognizable side effects during 12 months of follow-up. In conclusion, low-dose oral lysine supplementation is potentially beneficial to patients with LPI and can be started safely at an early age.