Increased risk of persistent neuropathic pain after traumatic nerve injury and surgery for carriers of a human leukocyte antigen haplotype.

ABSTRACT: It is not known why some patients develop persistent pain after nerve trauma while others do not. Among multiple risk factors for the development of persistent posttrauma and postsurgical pain, a neuropathic mechanism due to iatrogenic nerve lesion has been proposed as the major cause of these conditions. Because there is some evidence that the human leukocyte antigen (HLA) system plays a role in persistent postsurgical pain, this study aimed to identify the genetic risk factors, specifically among HLA loci, associated with chronic neuropathic pain after traumatic nerve injuries and surgery in the upper extremities. Blood samples were taken to investigate the contribution of HLA alleles (ie, HLA-A, HLA-B, HLA-DRB1, HLA-DQB1, and HLA-DPB1) in a group of patients with persistent neuropathic pain (n = 70) and a group of patients with neuropathy without pain (n = 61). All subjects had intraoperatively verified nerve damage in the upper extremity. They underwent bedside clinical neurological examination to identify the neuropathic pain component according to the present grading system of neuropathic pain. Statistical analyses on the allele and haplotype were conducted using the BIGDAWG package. We found that the HLA haplotype A*02:01-B*15:01-C*03:04-DRB1*04:01-DQB1*03:02 was associated with an increased risk of developing persistent neuropathic pain in the upper extremity (OR = 9.31 [95% CI 1.28-406.45], P < 0.05). No significant associations were found on an allele level when correcting for multiple testing. Further studies are needed to investigate whether this association is on a haplotypic level or if certain alleles may be causing the association.

Altered microvasculature in pancreatic islets from subjects with type 1 diabetes.

AIMS: The transcriptome of different dissociated pancreatic islet cells has been described in enzymatically isolated islets in both health and disease. However, the isolation, culturing, and dissociation procedures likely affect the transcriptome profiles, distorting the biological conclusions. The aim of the current study was to characterize the cells of the islets of Langerhans from subjects with and without type 1 diabetes in a way that reflects the in vivo situation to the highest possible extent. METHODS: Islets were excised using laser capture microdissection directly from frozen pancreatic tissue sections obtained from organ donors with (n = 7) and without (n = 8) type 1 diabetes. Transcriptome analysis of excised samples was performed using AmpliSeq. Consecutive pancreatic sections were used to estimate the proportion of beta-, alpha-, and delta cells using immunofluorescence and to examine the presence of CD31 positive endothelial regions using immunohistochemistry. RESULTS: The proportion of beta cells in islets from subjects with type 1 diabetes was reduced to 0% according to both the histological and transcriptome data, and several alterations in the transcriptome were derived from the loss of beta cells. In total, 473 differentially expressed genes were found in the islets from subjects with type 1 diabetes. Functional enrichment analysis showed that several of the most upregulated gene sets were related to vasculature and angiogenesis, and histologically, vascular density was increased in subjects with type 1 diabetes. Downregulated in type 1 diabetes islets was the gene set epithelial mesenchymal transition. CONCLUSION: A number of transcriptional alterations are present in islets from subjects with type 1 diabetes. In particular, several gene sets related to vasculature and angiogenesis are upregulated and there is an increased vascular density, suggesting an altered microvasculature in islets from subjects with type 1 diabetes. By studying pancreatic islets extracted directly from snap-frozen pancreatic tissue, this study reflects the in vivo situation to a high degree and gives important insights into islet pathophysiology in type 1 diabetes.

Histological and transcriptional characterization of the pancreatic acinar tissue in type 1 diabetes.

INTRODUCTION: Despite a reduced function and volume of the exocrine pancreas in type 1 diabetes, the acinar cells remain understudied in type 1 diabetes research. The hypothesis of this study is that the acinar tissue is altered in subjects with type 1 diabetes compared with subjects without diabetes. RESEARCH DESIGN AND METHODS: The cell density, expression of digestive enzymes, and transcriptome of acinar tissue at varying distances from islets were analyzed using histology, immunostaining, and AmpliSeq RNA sequencing of laser capture microdissected tissue. Pancreases examined were from organ donors with or without type 1 diabetes. RESULTS: We demonstrate preserved acinar nuclei density and find no support of acinar atrophy in type 1 diabetes. Staining for digestive enzymes (amylase, lipase, and trypsin) demonstrated an evenly distributed expression in the exocrine parenchyma; although occasional amylase-negative regions appeared in tissue that had been formalin-fixed and paraffin-embedded, this phenomenon was not evident in frozen tissue. Gene set enrichment analysis of whole transcriptome data identified transcriptional alterations in type 1 diabetes that were present in the acinar tissue independent of the distance from islets. Among these, the two most enriched gene sets were Myc Targets V2 and Estrogen Response Early. CONCLUSION: Taken together, these new data emphasize the involvement of the entire pancreas in type 1 diabetes pathology. The alteration of the gene sets Myc Targets V2 and Estrogen Response Early is a possible link to the increased incidence of pancreatic cancer in type 1 diabetes.

Transcriptional analysis of islets of Langerhans from organ donors of different ages.

Insulin secretion is impaired with increasing age. In this study, we aimed to determine whether aging induces specific transcriptional changes in human islets. Laser capture microdissection was used to extract pancreatic islet tissue from 37 deceased organ donors aged 1-81 years. The transcriptomes of the extracted islets were analysed using Ion AmpliSeq sequencing. 346 genes that co-vary significantly with age were found. There was an increased transcription of genes linked to senescence, and several aspects of the cell cycle machinery were downregulated with increasing age. We detected numerous genes not linked to aging in previous studies likely because earlier studies analysed islet cells isolated by enzymatic digestion which might affect the islet transcriptome. Among the novel genes demonstrated to correlate with age, we found an upregulation of SPP1 encoding osteopontin. In beta cells, osteopontin has been seen to be protective against both cytotoxicity and hyperglycaemia. In summary, we present a transcriptional profile of aging in human islets and identify genes that could affect disease course in diabetes.

Transcriptional profiles of human islet and exocrine endothelial cells in subjects with or without impaired glucose metabolism.

In experimental studies, pancreatic islet microvasculature is essential for islet endocrine function and mass, and islet vascular morphology is altered in diabetic subjects. Even so, almost no information is available concerning human islet microvascular endothelial cell (MVEC) physiology and gene expression. In this study, islets and exocrine pancreatic tissue were acquired from organ donors with normoglycemia or impaired glucose metabolism (IGM) immediately after islet isolation. Following single-cell dissociation, primary islet- and exocrine MVECs were obtained through fluorescence-activated cell sorting (FACS) and transcriptional profiles were generated using AmpliSeq. Multiple gene sets involved in general vascular development and extracellular matrix remodeling were enriched in islet MVEC. In exocrine MVEC samples, multiple enriched gene sets that relate to biosynthesis and biomolecule catabolism were found. No statistically significant enrichment was found in gene sets related to autophagy or endoplasmic reticulum (ER) stress. Although ample differences were found between islet- and exocrine tissue endothelial cells, no differences could be observed between normoglycemic donors and donors with IGM at gene or gene set level. Our data is consistent with active angiogenesis and vascular remodeling in human islets and support the notion of ongoing endocrine pancreas tissue repair and regeneration even in the adult human.

A new allele found in a volunteer hematopoietic stem cell donor: HLA-B*15:465.

HLA-B*15:465 differs from HLA-B*15:01:01:01 in codon 336 of exon 7.

Validation of an algorithm for chronic periodontitis risk assessment and prognostication: analysis of an inflammatory reactivity test and selected risk predictors.

BACKGROUND: Patients with severe forms of chronic periodontitis present with varying degrees of decreased inflammatory reactivity. A previously reported algorithm for chronic periodontitis risk assessment and prognostication is based on the analysis of some 20 risk predictors. One of these predictors is a skin provocation test that assesses the individual patient's reactivity to a lipid A challenge. The aim of this report was to analyze results from validation data for the algorithm with respect to the contribution of results of the skin provocation test as a risk predictor for the progression of chronic periodontitis and to compare these results with the contribution from other predictors, namely smoking, angular bony destruction, furcation involvement, abutment teeth, and endodontic pathology. METHODS: Data from a previously reported clinical validation sample were used for the analysis, including the calculation of quality measures and explanatory values using different types of regression analysis and non-parametric testing. RESULTS: Smoking, endodontic pathology, abutment teeth, angular bony destruction, and furcation involvement presented with individual explanatory values for periodontitis progression between 4% and 13% and highly significant parameter estimates. Explanatory values for the results of the skin provocation test ranged between 2.6% and 5.1% depending on the disease severity group, with a positive predictive value of 82% for the identification of high-risk patients. CONCLUSION: The skin provocation test provided a clinically significant contribution to the quality of analysis with the periodontitis risk and prognostication algorithm, in particular in the selection of high-risk patients for in-depth individual tooth analysis.

Validation of an algorithm for chronic periodontitis risk assessment and prognostication: risk predictors, explanatory values, measures of quality, and clinical use.

BACKGROUND: The American Academy of Periodontology has recently stated that, "[risk assessment will become] increasingly important in periodontal treatment planning and should be part of every comprehensive dental and periodontal evaluation." (J Periodontol 2006;77:1608). Unaided risk assessment and prognostication show significant variability because chronic periodontitis is a multifactorial disease. This report summarizes the clinical validation of an algorithm for chronic periodontitis risk assessment and prognostication. The algorithm is a Web-based analytic tool that integrates some 20 risk predictors and calculates scores indicating levels of risk for chronic periodontitis for the dentition (Level I) and, if an elevated risk is found, prognosticates disease progression tooth by tooth (Level II). METHODS: An independent clinical validation sample was generated in an open, prospective clinical trial and analyzed in a predetermined validation plan. RESULTS: The analyses identified two threshold scores above which significant progression of periodontitis was found. Based on these scores, sufficiently high explanatory values with significant and increasing parameter estimates for increasing risk were established in Level I, justifying detailed analysis tooth by tooth in Level II. Subsequent prognostication of chronic periodontitis in Level II was found to be accompanied by clinically relevant measures of quality in relation to rates of disease progression. Three score intervals representing increasing levels of periodontitis progression were identified corresponding to increasing levels of significant annual marginal bone loss. CONCLUSIONS: The predictors included in the algorithm reflect a relevant selection for periodontitis risk assessment. Risk assessment and prognostication with the algorithm provides the clinician with a validated, reliable, consistent, and objective tool supporting treatment planning.