R. Keith Campbell

The first chordates appear in the fossil record at the time of the Cambrian explosion, nearly 550 million years ago. The modern ascidian tadpole represents a plausible approximation to these ancestral chordates. To illuminate the origins of chordate and vertebrates, we generated a draft of the protein-coding portion of the genome of the most studied ascidian, Ciona intestinalis . The Ciona genome contains ∼16,000 protein-coding genes, similar to the number in other invertebrates, but only half that found in vertebrates. Vertebrate gene families are typically found in simplified form in Ciona , suggesting that ascidians contain the basic ancestral complement of genes involved in cell signaling and development. The ascidian genome has also acquired a number of lineage-specific innovations, including a group of genes engaged in cellulose metabolism that are related to those in bacteria and fungi.

PURPOSE: The epidemiology, classification, pathology, and treatment of diabetic neuropathy are reviewed. SUMMARY: Diabetic peripheral neuropathy is a common complication of diabetes that can cause significant morbidity and mortality. Some 30% of hospitalized and 20% of community-dwelling diabetes patients have peripheral neuropathy; the annual incidence rate is approximately 2%. The primary risk factor is hyperglycemia. Sensorimotor neuropathy is marked by pain, paresthesia, and sensory loss. Cardiac autonomic neuropathy (CAN) may contribute to myocardial infarction, malignant arrhythmia, and sudden death. Gastroparesis is the most debilitating complication of gastrointestinal autonomic neuropathy. Genitourinary autonomic neuropathy can cause sexual dysfunction and neurogenic bladder. The pathology of diabetic neuropathy involves oxidative stress, advanced glycation end products, polyol pathway flux, and protein kinase C activation; all contribute to microvascular disease and nerve dysfunction. For symptom management current evidence from clinical trials supports the use of desipramine, amitriptyline, capsaicin, tramadol, gabapentin, bupropion, and venlafaxine as preferred medications. Citalopram, nonsteroidal antiinflammatory drugs, and opioid analgesics may be used as adjuvant agents. Lamotrigine, oxcarbazepine, paroxetine, levodopa, and alpha-lipoic acid are alternative considerations. Evidence supporting the use of zonisamide, fluoxetine, mexiletine, dextromethorphan, and phenytoin is considered equivocal. Complementary therapies have also shown efficacy. The symptoms of CAN may be ameliorated with fludrocortisone, clonidine, midodrine, dihydroergotamine or caffeine, octreotide, and beta-blockers. Gastroparesis may be treated with metoclopramide or erythromycin. The most promising disease-modifying therapy is ruboxistaurin, which is in Phase III trials. Glycemic control remains the foundation of prevention and the prerequisite of adequate treatment. CONCLUSION: Diabetic neuropathy is a many-faceted complication of diabetes that can be managed symptomatically with an array of drugs.

We examined whether persistence of epigenetic DNA methylation (DNA-me) alterations at specific loci over two different time points in people with diabetes are associated with metabolic memory, the prolonged beneficial effects of intensive vs. conventional therapy during the Diabetes Control and Complications Trial (DCCT) on the progression of microvascular outcomes in the long-term follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) Study. We compared DNA-me profiles in genomic DNA of whole blood (WB) isolated at EDIC Study baseline from 32 cases (DCCT conventional therapy group subjects showing retinopathy or albuminuria progression by EDIC Study year 10) vs. 31 controls (DCCT intensive therapy group subjects without complication progression by EDIC year 10). DNA-me was also profiled in blood monocytes (Monos) of the same patients obtained during EDIC Study years 16-17. In WB, 153 loci depicted hypomethylation, and 225 depicted hypermethylation, whereas in Monos, 155 hypomethylated loci and 247 hypermethylated loci were found (fold change ≥1.3; P < 0.005; cases vs. controls). Twelve annotated differentially methylated loci were common in both WB and Monos, including thioredoxin-interacting protein (TXNIP), known to be associated with hyperglycemia and related complications. A set of differentially methylated loci depicted similar trends of associations with prior HbA1c in both WB and Monos. In vitro, high glucose induced similar persistent hypomethylation at TXNIP in cultured THP1 Monos. These results show that DNA-me differences during the DCCT persist at certain loci associated with glycemia for several years during the EDIC Study and support an epigenetic explanation for metabolic memory.