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OBJECTIVETumor necrosis factor ligand family members B-cell–activating factor (BAFF) and a proliferation-inducing ligand (APRIL) can exert powerful effects on B-cell activation and development, type 1 T-helper cell (Th1) immune responses, and autoimmunity. We examined the effect of blocking BAFF and APRIL on the development of autoimmune diabetes.RESEARCH DESIGN AND METHODSFemale NOD mice were administered B-cell maturation antigen (BCMA)-Fc from 9 to 15 weeks of age. Diabetes incidence, islet pathology, and T- and B-cell populations were examined.RESULTSBCMA-Fc treatment reduced the severity of insulitis and prevented diabetes development in NOD mice. BCMA-Fc–treated mice showed reduced follicular, marginal-zone, and T2MZ B-cells. B-cell reduction was accompanied by decreased frequencies of pathogenic CD4+CD40+ T-cells and reduced Th1 cytokines IL-7, IL-15, and IL-17. Thus, T-cell activation was blunted with reduced B-cells. However, BCMA-Fc–treated mice still harbored detectable diabetogenic T-cells, suggesting that regulatory mechanisms contributed to diabetes prevention. Indeed, BCMA-Fc–treated mice accumulated increased CD4+CD25+ regulatory T-cells (Tregs) with age. CD4+CD25+ cells were essential for maintaining euglycemia because their depletion abrogated BCMA-Fc–mediated protection. BCMA-Fc did not directly affect Treg homeostasis given that CD4+CD25+Foxp3+ T-cells did not express TACI or BR3 receptors and that CD4+CD25+Foxp3+ T-cell frequencies were equivalent in wild-type, BAFF−/−, TACI−/−, BCMA−/−, and BR3−/− mice. Rather, B-cell depletion resulted in CD4+CD25+ T-cell–mediated protection from diabetes because anti-CD25 monoclonal antibody treatment precipitated diabetes in both diabetes-resistant NOD.μMT−/− and BCMA-Fc–treated mice.CONCLUSIONSBAFF/APRIL blockade prevents diabetes. BCMA-Fc reduces B-cells, subsequently blunting autoimmune activity and allowing endogenous regulatory mechanisms to preserve a prehyperglycemic state.

Malle et al. identify a role for nuclear factor inducing κB (NIK) in pancreatic β cell failure. NIK activation disrupts glucose homeostasis in zebrafish in vivo and impairs glucose-stimulated insulin secretion in mouse and human islets in vitro. NIK activation also perturbs β cell insulin secretion in a diet-induced obesity mouse model. These studies reveal that NIK contributes a central mechanism for β cell failure in obesity.

Current approaches in tissue engineering are geared toward generating tissue-specific stem cells. Given the complexity and heterogeneity of tissues, this approach has its limitations. An alternate approach is to induce terminally differentiated cells to dedifferentiate into multipotent proliferative cells with the capacity to regenerate all components of a damaged tissue, a phenomenon used by salamanders to regenerate limbs. 5-Azacytidine (AZA) is a nucleoside analog that is used to treat preleukemic and leukemic blood disorders. AZA is also known to induce cell plasticity. We hypothesized that AZA-induced cell plasticity occurs via a transient multipotent cell state and that concomitant exposure to a receptive growth factor might result in the expansion of a plastic and proliferative population of cells. To this end, we treated lineage-committed cells with AZA and screened a number of different growth factors with known activity in mesenchyme-derived tissues. Here, we report that transient treatment with AZA in combination with platelet-derived growth factor–AB converts primary somatic cells into tissue-regenerative multipotent stem (iMS) cells. iMS cells possess a distinct transcriptome, are immunosuppressive, and demonstrate long-term self-renewal, serial clonogenicity, and multigerm layer differentiation potential. Importantly, unlike mesenchymal stem cells, iMS cells contribute directly to in vivo tissue regeneration in a context-dependent manner and, unlike embryonic or pluripotent stem cells, do not form teratomas. Taken together, this vector-free method of generating iMS cells from primary terminally differentiated cells has significant scope for application in tissue regeneration.

Twelve patients were studied within 48 hours of stroke using positron emission tomography to determine cerebral blood flow (CBF), cerebral metabolic rate for oxygen (CMRO2), oxygen extraction fraction, cerebral blood volume, cerebral pH (CpH), and cerebral metabolic rate for glucose (CMRGlc), the last calculated using published normal rate constants (CMRGlc[N]) and those for severe ischemia. In these studies, a cortical region of severe ischemia (I) was outlined, its metabolic and perfusion properties evaluated, and its length measured. The contralateral uninvolved cortical rim (C) in these patients and the cortical rim in 5 older normal patients were used for comparison. The length of region I correlated with the neurological deficit measured independently by a clinical scoring method. The 12 patients fell into two groups: Group I (8 patients), whose CBF in I was 9.3 +/- 2.5 ml/100 gm/min (mean +/- SEM) and was in every patient lower than that in C (33.1 +/- 2.2), and Group 2 (4 patients), whose CBF in I was 42.1 +/- 8.5 ml/100 gm/min and was in every case higher than that in C (28.2 +/- 1.5). In Group I, region I showed a CMRGlc(N)/CMRO2 ratio of 0.22 +/- 0.06 and a CpH of 6.83 +/- 0.06. In Group 2, the same ratio in the region I was 0.58 +/- 0.09 and the CpH was 7.12 +/- 0.05. The CMRGlc (N)/CMRO2 ratio for the contralateral hemisphere was comparable in the two groups. Our data suggest that, within 48 hours of the clinical onset of stroke, the ischemic cortex is already reperfused in one third of patients. Those ischemic regions with persistent hypoperfusion appear acidotic, whereas in the reperfused regions, despite evidence of an increased CMRGlc/CMRO2 ratio, acidosis is not evident. The implications of these findings for therapies proposed in acute human cerebral ischemia are discussed.

Background: Ischemia-reperfusion injury (IRI) is one of the major risk factors implicated in morbidity and mortality associated with cardiovascular disease. During cardiac ischemia, the build-up of acidic metabolites results in decreased intracellular and extracellular pH that can reach as low as 6.0-6.5. The resulting tissue acidosis exacerbates ischemic injury and significantly impacts cardiac function. Methods: We used genetic and pharmacological methods to investigate the role of acid sensing ion channel 1a (ASIC1a) in cardiac IRI at the cellular and whole organ level. Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) as well as ex vivo and in vivo models of IRI were used to test the efficacy of ASIC1a inhibitors as pre- and post-conditioning therapeutic agents. Results: Analysis of human complex trait genetics indicate that variants in the ASIC1 genetic locus are significantly associated with cardiac and cerebrovascular ischemic injuries. Using hiPSC-CMs in vitro and murine ex vivo heart models, we demonstrate that genetic ablation of ASIC1a improves cardiomyocyte viability after acute IRI. Therapeutic blockade of ASIC1a using specific and potent pharmacological inhibitors recapitulates this cardioprotective effect. We used an in vivo model of myocardial infarction (MI) and two models of ex vivo donor heart procurement and storage as clinical models to show that ASIC1a inhibition improves post-IRI cardiac viability. Use of ASIC1a inhibitors as pre- or post-conditioning agents provided equivalent cardioprotection to benchmark drugs, including the sodium-hydrogen exchange inhibitor zoniporide. At the cellular and whole organ level, we show that acute exposure to ASIC1a inhibitors has no impact on cardiac ion channels regulating baseline electromechanical coupling and physiological performance. Conclusions: Collectively, our data provide compelling evidence for a novel pharmacological strategy involving ASIC1a blockade as a cardioprotective therapy to improve the viability of hearts subjected to IRI.

Background.-Migraine pathophysiology is complex and probably involves cortical and subcortical alterations. Structural and functional brain imaging studies indicate alterations in the higher order visual cortex in patients with migraine. Arterial spin labeling magnetic resonance imaging (ASL-MRI) is a non-invasive imaging method for assessing changes in cerebral blood flow (CBF) in vivo.Objective. -To examine if interictal CBF differs between patients with episodic migraine (EM) with or without aura and healthy controls (HC).Methods.-We assessed interictal CBF using 2D pseudo-continuous ASL-MRI on a 3 Tesla Philips scanner (University Hospital Zurich, Switzerland) in EM (N = 17, mean age 32.7 ± 9.9, 13 females) and HC (N = 19, mean age 31.0 ± 9.3, 11 females).Results.-Compared to HC, EM showed exclusively hyperperfusion in the right MT+ and Cohen's d effect size was 0.99 (HC mean CBF ± SD: 33.1 ± 5.9 mL/100 g/minutes; EM mean CBF: 40.9 ± 9.4 mL/100 g/minutes). EM with aura (N = 13, MwA) revealed hyperperfusion compared to HC in the right MT+ and superior temporal gyrus. For MT, Cohen's d effect size was 1.34 (HC mean CBF ± SD: 33.1 ± 5.9 mL/100 g/minutes; MwA mean CBF: 43.3 ± 8.6 mL/100 g/minutes). For the superior temporal gyrus, Cohen's d effect size was 1.28 (HC mean CBF ± SD: 40.1 ± 4.9 mL/100 g/minutes; MwA mean CBF: 47.4 ± 6.4 mL/100 g/minutes). In EM, anxiety was positively associated with CBF in the parietal operculum and angular gyrus.Conclusions.-Our results suggest that extrastriate brain regions probably involved in cortical spreading depression are associated with CBF changes in the interictal state. We conclude that ASL-MRI is a sensitive method to identify local neurofunctional abnormalities in CBF in patients with EM in the interictal state.