Immediate effects of rhythmic joint mobilization of the temporomandibular joint on pain, mouth opening and electromyographic activity in patients with temporomandibular disorders

BACKGROUND

Rhythmic joint mobilizations (RJM) of the temporomandibular joint (TMJ) are employed to relieve pain and improve function in patients with temporomandibular disorders (TMD). However, the evidence on the immediate effects of RJM in patients with TMD is scarce. The aim of this study was to assess the immediate clinical and functional effects of RJM in patients with TMD.

MATERIALS AND METHODS

This was a one-group quasi-experimental before and after study. Thirty-eight patients with TMD were assessed by means of pain intensity (visual analogue score, VAS), pressure pain threshold (PPT, measured through pressure algometry on the masseter and temporal muscles), mouth opening (MO, measured with a ruler), and surface electromyographic activity of the masseter and temporal muscles (asymmetry index, AI). Measurements were performed before and after a single, 1-min session of RJM of each TMJ. All statistical analyses were performed using the SPSS version 20.0 statistical package.

RESULTS

A statistical significant difference was found in pain intensity, PPT and MO after the intervention (p < 0.05). No difference was found in the AI. A large effect size was observed for pain intensity, PPT of the left and right masseter muscles and MO (d = 0.85-1.13), whereas for the left and right temporal muscles the effect size was moderate (d = 0.62) and small, respectively (d = 0.49).

CONCLUSION

In this sample of patients with TMD, a single session of RJM of the TMJ seemed to be effective in reducing pain intensity, increasing PPT and improving MO immediately after the intervention, without differences in the AI.

Osmophobia in Migraine and Tension-Type Headache and Its Clinical Features in Patients With Migraine

Intolerance to smell is often reported by migraine patients. This study evaluates osmophobia in connection with the diagnosis of migraine and episodic tension-type headache (ETTH). The characteristics of this symptom are also investigated. We recruited from our Headache Centre 1005 patients (772 female, 233 male; age 37 ± 11 years), of whom 677 were migraine without aura (MoA), 130 migraine with aura (MA) and 198 TTH. Patients with two or more forms of primary headache were excluded. Among migraine patients, 43.9% with MoA and 38.5% with MA reported osmophobia during the attacks; none of the 198 TTH patients suffered this symptom. Most frequently offending odours were scents (63.9%), food (55.2%) and cigarette smoke (54.8%). Osmophobia appears structurally integrated into the migraine history of the patient. It seems to be a peculiar symptom favouring the diagnosis of migraine (MoA and MA) in the differential diagnosis with ETTH.

Novel HLA-DP region susceptibility loci associated with severe acute GvHD

Despite HLA allele matching, significant acute GvHD remains a major barrier to successful unrelated donor BMT. We conducted a genome-wide association study (GWAS) to identify recipient and donor genes associated with the risk of acute GvHD. A case-control design (grade III-IV versus no acute GvHD) and pooled GWA approach was used to study European-American recipients with hematological malignancies who received myeloablative conditioning non-T-cell-depleted first transplantation from HLA-A, -B, -C, -DRB1, -DQB1 allele level (10/10) matched unrelated donors. DNA samples were divided into three pools and tested in triplicate using the Affymetrix Genome-wide SNP Array 6.0. We identified three novel susceptibility loci in the HLA-DP region of recipient genomes that were associated with III-IV acute GvHD (rs9277378, P=1.58E-09; rs9277542, P=1.548E-06 and rs9277341, P=7.718E-05). Of these three single nucleotide polymorphisms (SNPs), rs9277378 and rs9277542 are located in non-coding regions of the HLA-DPB1 gene and the two are in strong linkage disequilibrium with two other published SNPs associated with acute GvHD, rs2281389 and rs9277535. Eighteen other recipient SNPs and 3 donor SNPs with a high level of significance (8E-07 or lower) were found. Our report contributes to emerging data showing clinical significance of the HLA-DP region genetic markers beyond structural matching of DPB1 alleles.

Chronic Paroxysmal Hemicrania, Hemicrania Continua and Sunct Syndrome in Association with Other Pathologies: A Review

We present a review of 22 cases of headache mimicking chronic paroxysmal hemicrania (CPH) (17 female and five male; F : M ratio 3.4), nine cases mimicking hemicrania continua (HC) (seven female and two male) and seven cases mimicking SUNCT syndrome (five male and two female) found in association with other pathologies published from 1980 up to the present. All case reports were discussed with respect to diagnostic criteria proposed by International Headache Society (IHS) for CPH, by Goadsby and Lipton for HC and SUNCT, and evaluated to identify a possible causal relationship between the pathology and the onset of headache. The aim of the present review was to evaluate if the presence of associated lesions and their location could help elucidate the pathogenesis of trigeminal autonomic cephalalgias (TACs).

Retrospective cohort study comparing activated partial thromboplastin time versus anti-factor Xa activity nomograms for therapeutic unfractionated heparin monitoring in pediatrics

BACKGROUND

Unfractionated heparin (UFH) is widely used to treat thromboembolic disease, but monitoring in children is challenging. Both activated partial thromboplastin time (aPTT) and anti-factor Xa activity (anti-Xa) are utilized, but a comparison of dosing nomograms has not been reported in pediatrics.

OBJECTIVE

To compare the performance of aPTT and anti-Xa for UFH monitoring in pediatric patients.

DESIGN/METHODS

A retrospective cohort study was conducted in patients ≤ 21 years old treated with UFH at Johns Hopkins Hospital from January 2009 to May 2011. For monitoring, an aPTT nomogram was used for the initial 15 months, and an anti-Xa nomogram was used for the subsequent 12 months. Clinical characteristics, laboratory data and outcomes were analyzed.

RESULTS

Thirty-four patients were monitored with aPTT and 26 patients with anti-Xa. There was no significant difference in median time to therapeutic range (11.6 h aPTT, 95%CI = 6.0-17.0; 9.9 h anti-Xa, 95%CI = 7.3-20.7) or per cent of patients achieving therapeutic measurements at 24 (79% aPTT, 95%CI = 62-91; 73% anti-Xa, 95%CI = 52-88) and 48 h (88% aPTT, 95%CI = 73-97; 96% anti-Xa, 95%CI = 80-100). However, anti-Xa measurements were more frequently therapeutic than aPTT (74% [95%CI = 69-78] vs. 54% [95%CI = 50-59]). Variance between anti-Xa and aPTT measurements was high (R(2)  = 0.236). No significant difference was seen in bleeding incidence (9% aPTT, 95%CI = 2-24; 15% anti-Xa, 95%CI = 4-35).

CONCLUSION

The time to achieve therapeutic measures and bleeding outcomes were not significantly different between anti-Xa and aPTT nomograms. However, a small study size limits the power to detect clinically relevant differences. The results warrant larger prospective studies of UFH monitoring in children with thromboembolic disease.

Pig-to-monkey islet xenotransplantation using multi-transgenic pigs

The generation of pigs with genetic modifications has significantly advanced the field of xenotransplantation. New genetically engineered pigs were produced on an α1,3-galactosyltransferase gene-knockout background with ubiquitous expression of human CD46, with islet beta cell-specific expression of human tissue factor pathway inhibitor and/or human CD39 and/or porcine CTLA4-lg. Isolated islets from pigs with 3, 4 or 5 genetic modifications were transplanted intraportally into streptozotocin-diabetic, immunosuppressed cynomolgus monkeys (n = 5). Immunosuppression was based on anti-CD154 mAb costimulation blockade. Monitoring included features of early islet destruction, glycemia, exogenous insulin requirement and histopathology of the islets at necropsy. Using these modified pig islets, there was evidence of reduced islet destruction in the first hours after transplantation, compared with two series of historical controls that received identical therapy but were transplanted with islets from pigs with either no or only one genetic modification. Despite encouraging effects on early islet loss, these multi-transgenic islet grafts did not demonstrate consistency in regard to long-term success, with only two of five demonstrating function beyond 5 months.

Retinoic acid-producing, ex-vivo-generated human tolerogenic dendritic cells induce the proliferation of immunosuppressive B lymphocytes

While much is known about tolerogenic dendritic cell effects on forkhead box protein 3 (FoxP3)⁺ regulatory T cells, virtually nothing is known about their effects on another arm of immunoregulation that is mediated by a subpopulation of immunosuppressive B cells. These cells suppress rheumatoid arthritis, lupus and inflammatory bowel disease in mice, and functional defects have been reported in human lupus. We show that co-stimulation-impaired tolerogenic dendritic cells that prevent and reverse type 1 diabetes mellitus induce the proliferation of human immunosuppressive B cells in vitro. We also show that the suppressive properties of these B cells concentrate inside the CD19⁺ CD24⁺ B cell population and more specifically inside the CD19⁺ CD24⁺ CD38⁺ regulatory B cell population. We discovered that B cell conversion into suppressive cells in vitro is partially dependent on dendritic cell production of retinoic acid and also that CD19⁺ CD24⁺ CD38⁺ B regulatory cells express retinoic acid receptors. Taken together, our data suggest a model whereby part of the immunosuppressive properties of human tolerogenic dendritic cells could be mediated by retinoic acid which, in addition to its known role in favouring T cell differentiation to FoxP3⁺ regulatory T cells, acts to convert B cells into immunosuppressive cells.

Administration of a negative vaccination induces hyporesponsiveness to islet allografts

As a result of less than optimal outcomes the use of islet allografts as a standard insulin replacement therapy is limited to adults with a history of extreme glucose dysregulation and hypoglycemia unawareness. In this study, we examined the use of prophylactic immunotherapy to prevent islet allograft rejection in the absence of antirejection drugs. Our protocol to achieve allograft acceptance used a negative vaccination strategy that is comprised of apoptotic donor cells delivered in Incomplete Freund's Adjuvant (IFA) 1 week prior to islet transplantation. The goal of this new protocol is to elicit hyporesponsiveness to alloantigen prior to islet transplantation. First, we examined our protocol without islet allograft transplants and determined that the negative vaccination was not globally immunosuppressive or immunostimulatory. Islet allograft experiments using fully MHC-mismatched islet donors and recipients demonstrated that the negative vaccination strategy induced long-term islet allograft acceptance. Upon rechallenge with alloantigen, the negative vaccination protocol successfully achieved hyporesponsiveness. In addition, the microenvironment at the site of the tolerant allograft revealed a decrease in proinflammatory mediators (IFN-γ, TNF-α) and an increase in the anti-inflammatory mediator IL-10, as well as increased expression of the master regulator of T-regulatory cells, FOXP3. Our data suggest that pretreating allograft recipients with apoptotic donor alloantigen delivered in IFA induced long-term islet allograft acceptance and glycemic control by introducing alloantigen to the recipient immune system in a nonimmunostimulatory manner prior to transplant.

Improved quality of life following total pancreatectomy and auto-islet transplantation for chronic pancreatitis

BACKGROUND

Total pancreatectomy (TP) with auto-islet transplant (AIT) is an extreme treatment for chronic pancreatitis, and we reviewed our experience to assess the impact on quality of life (QOL).

METHODS

A prospective cohort study from 2007 through 2010 with pre- and postoperative assessments of the Depression Anxiety Stress Scale, Pain Disability Index, and visual analogue pain scale was performed.

RESULTS

Twenty patients underwent TP-AIT with a median follow-up of 12 months (6.75-24 months). All patients reported moderate (45 %) to severe (55 %) pain prior to surgery. TP-AIT resulted in significant decreases in abdominal pain (p < 0.001), 80 % reporting no or mild pain. Despite pain improvement, only 30 % discontinued narcotics. Improvements in all PDI QOL domains improved from 79 to 90 % (p = 0.002), with greatest improvements seen in those without prior pancreatic surgery, younger patients, and in those with higher levels of preoperative pain. Patients were less affected by depression and anxiety prior to surgery, but 60 and 70 % did show improvement in depression and anxiety, respectively (p = 0.033). Sixteen patients (80 %) required exogenous insulin at last follow-up (mean total dose of insulin 11.6 U/day).

CONCLUSIONS

TP-AIT significantly improves pain and QOL measures in appropriately selected patients with CP.

C-peptide reduces high-glucose-induced apoptosis of endothelial cells and decreases NAD(P)H-oxidase reactive oxygen species generation in human aortic endothelial cells

AIMS/HYPOTHESIS

Reactive oxygen species (ROS) generated during hyperglycaemia are implicated in the development of diabetic vascular complications. High glucose increases oxidative stress in endothelial cells and induces apoptosis. A major source of ROS in endothelial cells exposed to glucose is the NAD(P)H oxidase enzyme. Several studies demonstrated that C-peptide, the product of proinsulin cleavage within the pancreatic beta cells, displays anti-inflammatory effects in certain models of vascular dysfunction. However, the molecular mechanism underlying this effect is unclear. We hypothesised that C-peptide reduces glucose-induced ROS generation by decreasing NAD(P)H oxidase activation and prevents apoptosis

METHODS

Human aortic endothelial cells (HAEC) were exposed to 25 mmol/l glucose in the presence or absence of C-peptide and tested for protein quantity and activity of caspase-3 and other apoptosis markers by ELISA, TUNEL and immunoblotting. Intracellular ROS were measured by flow cytometry using the ROS sensitive dye chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H(2)-DCDFA). NAD(P)H oxidase activation was assayed by lucigenin. Membrane and cytoplasmic levels of the NAD(P)H subunit ras-related C3 botulinum toxin substrate 1 (rho family, small GTP binding protein Rac1) (RAC-1) and its GTPase activity were studied by immunoblotting and ELISA. RAC-1 (also known as RAC1) gene expression was investigated by quantitative real-time PCR.

RESULTS

C-peptide significantly decreased caspase-3 levels and activity and upregulated production of the anti-apoptotic factor B cell CLL/lymphoma 2 (BCL-2). Glucose-induced ROS production was quenched by C-peptide and this was associated with a decreased NAD(P)H oxidase activity and reduced RAC-1 membrane production and GTPase activity.

CONCLUSIONS/INTERPRETATION

In glucose-exposed endothelial cells, C-peptide acts as an endogenous antioxidant molecule by reducing RAC-1 translocation to membrane and NAD(P)H oxidase activation. By preventing oxidative stress, C-peptide protects endothelial cells from glucose-induced apoptosis.

Interleukin-7 matures suppressive CD127(+) forkhead box P3 (FoxP3)(+) T cells into CD127(-) CD25(high) FoxP3(+) regulatory T cells

We have identified a novel interleukin (IL)-7-responsive T cell population [forkhead box P3 (FoxP3(+) ) CD4(+) CD25(+) CD127(+) ] that is comparably functionally suppressive to conventional FoxP3(+) CD4(+) CD25(+) regulatory T cells (T(regs) ). Although IL-2 is the most critical cytokine for thymic development of FoxP3(+) T(regs) , in the periphery other cytokines can be compensatory. CD25(+) CD127(+) T cells treated with IL-7 phenotypically 'matured' into the known 'classical' FoxP3(+) CD4(+) CD25(high) CD127(-) FoxP3(+) T(regs) . In freshly isolated splenocytes, the highest level of FoxP3 expression was found in CD127(+) CD25(+) T cells when compared with CD127(-) CD25(+) or CD127(+) CD25(-) cells. IL-7 treatment of CD4(+) CD25(+) T cells induced an increase in the accumulation of FoxP3 in the nucleus in vitro. IL-7-mediated CD25 cell surface up-regulation was accompanied by a concurrent down-regulation of CD127 in vitro. IL-7 treatment of the CD127(+) CD25(+) FoxP3(+) cells also resulted in up-regulation of cytotoxic T lymphocyte antigen 4 without any changes in CD45RA at the cell surface. Collectively, these data support emerging evidence that FoxP3(+) T cells expressing CD127 are comparably functionally suppressive to CD25(+) CD127(-) FoxP3(+) T cells. This IL-7-sensitive regulation of FoxP3(+) T(reg) phenotype could underlie one peripheral non-IL-2-dependent compensatory mechanism of T(reg) survival and functional activity, particularly for adaptive T(regs) in the control of autoimmunity or suppression of activated effector T cells.

Investigation of lymphocyte depletion and repopulation using alemtuzumab (Campath-1H) in cynomolgus monkeys

As the target CD52 molecule is expressed on erythrocytes of most nonhuman primate strains, using alemtuzumab in these species would cause massive hemolysis. Six cynomolgus monkeys of Indonesian origin, screened by agglutination assay for absence of CD52 on erythrocytes, were administered alemtuzumab in a cumulative dose to a maximum of 60 mg/kg. In two monkeys, mycophenolate mofetil (MMF) was added as maintenance therapy. Complete depletion of T and B lymphocytes (>99.5%) was achieved with 20 mg/kg alemtuzumab and was more profound than in monkeys treated with antithymocyte globulin (n = 5), as quantified by flow cytometry. Repopulation was suppressed by weekly injections of 10 mg/kg. Without MMF, repopulation of CD20(+)B cells and CD8(+)T cells was complete within 2 and 3 months, respectively, and repopulation of CD4(+)T cells was 67% after 1 year. MMF significantly delayed CD4(+)T-cell repopulation. Among repopulating CD4(+) and CD8(+) T cells, a phenotypic shift was observed from CD45RA(hi)CD62L(hi) naïve cells toward CD45RA(lo)CD62L(lo) effector memory cells. In lymph nodes, the depletion of naïve cells was more profound than of memory cells, which may have initiated a proliferation of memory cells. This model offers opportunities to investigate lymphocyte depletion/repopulation phenomena, as well as the efficacy of alemtuzumab in preclinical transplantation models.

Cluster-like headache. A comprehensive reappraisal

Among the primary headaches, cluster headache (CH) presents very particular features allowing a relatively easy diagnosis based on criteria listed in Chapter 3 of the International Classification of Headache Disorders (ICHD-II). However, as in all primary headaches, possible underlying causal conditions must be excluded to rule out a secondary cluster-like headache (CLH). The observation of some cases with clinical features mimicking primary CH, but of secondary origin, led us to perform an extended review of CLH reports in the literature. We identified 156 CLH cases published from 1975 to 2008. The more frequent pathologies in association with CLH were the vascular ones (38.5%, n = 57), followed by tumours (25.7%, n = 38) and inflammatory infectious diseases (13.5%, n = 20). Eighty were excluded from further analysis, because of inadequate information. The remaining 76 were divided into two groups: those that satisfied the ICHD-II diagnostic criteria for CH, 'fulfilling' group (F), n = 38; and those with a symptomatology in disagreement with one or more ICHD-II criteria, 'not fulfilling' group (NF), n = 38. Among the aims of this study was the possible identification of clinical features leading to the suspicion of a symptomatic origin. In the differential diagnosis with CH, red flags resulted both for F and NF, older age at onset; for NF, abnormal neurological/general examination (73.6%), duration (34.2%), frequency (15.8%) and localization (10.5%) of the attacks. We stress the fact that, on first observation, 50% of CLH presented as F cases, perfectly mimicking CH. Therefore, the importance of accurate, clinical evaluation and of neuroimaging cannot be overestimated.

Long-term controlled normoglycemia in diabetic non-human primates after transplantation with hCD46 transgenic porcine islets

Xenotransplantation of porcine islets into diabetic non-human primates is characterized by (i) an initial massive graft loss possibly due to the instant blood-mediated inflammatory reaction and (ii) the requirement of intensive, clinically unfriendly immunosuppressive therapy. We investigated whether the transgenic expression of a human complement-regulatory protein (hCD46) on porcine islets would improve the outcome of islet xenotransplantation in streptozotocin-induced diabetic Cynomolgus monkeys. Immunosuppression consisted of thymoglobulin, anti-CD154 mAb for costimulation blockade, and mycophenolate mofetil. Following the transplantation of islets from wild-type pigs (n = 2) or from 1,3-galactosyltransferase gene-knockout pigs (n = 2), islets survived for a maximum of only 46 days, as evidenced by return to hyperglycemia and the need for exogenous insulin therapy. The transplantation of islets from hCD46 pigs resulted in graft survival and insulin-independent normoglycemia in four of five monkeys for the 3 months follow-up of the experiment. One normalized recipient, selected at random, was followed for >12 months. Inhibition of complement activation by the expression of hCD46 on the pig islets did not substantially reduce the initial loss of islet mass, rather was effective in limiting antibody-mediated rejection. This resulted in a reduced need for immunosuppression to preserve a sufficient islet mass to maintain normoglycemia long-term.

Endoscopic gastric submucosal transplantation of islets (ENDO-STI): technique and initial results in diabetic pigs

The results of transplantation of human donor islets into the portal vein (PV) in patients with diabetes are encouraging. However, there are complications, for example, hemorrhage, thrombosis and an immediate loss of islets through the 'instant blood-mediated inflammatory reaction' (IBMIR). The gastric submucosal space (GSMS) offers potential advantages. Islets were isolated from adult pigs. Recipient pigs were made diabetic by streptozotocin. Donor islets were injected into the GSMS through a laparotomy (Group 1A, n = 4) or endoscopically (Group 1B, n = 8) or into the PV through a laparotomy (Group 2, n = 3). The pigs were followed for a maximum of 28 days. Monitoring of C-peptide in Group 1 indicated that there was minimal immediate loss of islets whereas in Group 2 there was considerable loss from IBMIR. In Group 1, there were significant reductions in mean blood glucose and mean exogenous insulin requirement between pretransplantation and 20 days posttransplantation. In Group 2, there was no significant reduction in either parameter. Insulin-positive cells were seen in the GSMS in Group 1, but not in the liver in Group 2. Endoscopic gastric submucosal transplantation of islets (ENDO-STI) offers a minimally invasive and quick approach to islet transplantation, avoids IBMIR and warrants further exploration.

Molecular variation at the HLA-A, B, C, DRB1, DQA1, and DQB1 loci in full heritage American Indians in Arizona: private haplotypes and their evolution

A sample of 492 full heritage, unrelated residents of the Gila River Indian Community (GRIC) of Arizona were characterized for their high-resolution DNA alleles at the HLA-A, B, C, DRB1, DQA1, and DQB1 loci. Only five allelic categories are found at HLA-A, 10 at HLA-B, 8 at HLA-C and HLA-DR, and 4 at DQA1 and DQB1. There is little evidence for population structure at the 6 loci. Two 'private' alleles, B*5102 and B*4005, which are found nearly exclusively in American Indian populations in the desert southwest and northern Mexico, are likely new mutations after the first inhabitation of the area, the evolution of which are reflected in the contemporary distribution of their respective haplotypes. DRB1*1402 has the highest reported frequency of any specificity at the DRB1 locus, 0.7461, and serves as a sensitive probe for locating related east Asian populations. The haplotypes in this population also exhibit a highly restricted distribution and strong genetic disequilibria, which has important implications for matching solid organ and bone marrow allografts. It is shown that, when one considers HLA-A-B-DRB1 homozygotes as allograft donors for all full heritage members of the GRIC, 50% of the community would find a non-mismatched organ within the homozygotes for the six most common haplotypes. This raises questions about transplantation policy and whether, in the presence of high-frequency private alleles and a restricted number of haplotypes, the full heritage American Indian community of the desert southwest should act as its own pool of donors for its affected members.

C-peptide is internalised in human endothelial and vascular smooth muscle cells via early endosomes

AIMS/HYPOTHESIS

There is increasing evidence that C-peptide exerts intracellular effects in a variety of cells and could be beneficial in patients with type 1 diabetes. Exactly how C-peptide achieves these effects, however, is unknown. Recent reports showed that C-peptide internalised in the cytoplasm of HEK-293 and Swiss 3T3 cells, where it was not degraded for at least 1 h after uptake. In this study, we investigated the hypothesis that C-peptide is internalised via an endocytic pathway and traffics to classic endocytic organelles, such as endosomes and lysosomes.

METHODS

We studied the internalisation of C-peptide in vascular endothelial and smooth muscle cells, two relevant targets of C-peptide activity, by using Alexa Fluor-labelled C-peptide probes in living cells and immunohistochemistry employing confocal laser-scanning microscopy. To examine trafficking to subcellular compartments, we used fluorescent constructs tagged to RAB5A, member RAS oncogene family (RAB5A) to identify early endosomes, or to lysosomal-associated membrane protein 1 (LAMP1) to identify lysosomes.

RESULTS

C-peptide internalised in the cytoplasm of cells within punctate structures identified as early endosomes. Internalisation was clearly detectable after 10 min of incubation and was blocked at 4 degrees C as well as with excess of unlabelled C-peptide. A minor fraction of vesicles, which increased with culture time, co-localised with lysosomes. Uptake of C-peptide was reduced by monodansylcadaverine, a pharmacological compound that blocks clathrin-mediated endocytosis, and by nocodazole, which disrupts microtubule assembly.

CONCLUSIONS/INTERPRETATION

C-peptide internalises in the cytoplasm of cells by endocytosis, as demonstrated by its localisation in early endosomes. Endosomes might represent a signalling station, through which C-peptide might achieve its cellular effects.

A new immunodeficient hyperglycaemic mouse model based on the Ins2Akita mutation for analyses of human islet and beta stem and progenitor cell function

AIMS/HYPOTHESIS

To develop and validate a new immunodeficient mouse strain that spontaneously develops a non-autoimmune hyperglycaemia to serve as a diabetic host for human islets and human beta stem and progenitor cells without the need for induction of hyperglycaemia by toxic chemicals with their associated side effects.

METHODS

We generated and characterised a new strain of immunodeficient spontaneously hyperglycaemic mice, the NOD-Rag1null Prf1null Ins2Akita strain and compared this strain with the NOD-scid Il2rgammanull (also known as Il2rg) immunodeficient strain rendered hyperglycaemic by administration of a single dose of streptozotocin. Hyperglycaemic mice were transplanted with human islets ranging from 1,000 to 4,000 islet equivalents (IEQ) and were monitored for normalisation of blood glucose levels.

RESULTS

NOD-Rag1null Prf1null Ins2Akita mice developed spontaneous hyperglycaemia, similar to Ins2Akita-harbouring strains of immunocompetent mice. Histological examination of islets in the host pancreas validated the spontaneous loss of beta cell mass in the absence of mononuclear cell infiltration. Human islets transplanted into spontaneously diabetic NOD-Rag1null Prf1null Ins2Akita and chemically diabetic NOD-scid Il2rgammanull mice resulted in a return to euglycaemia that occurred with transplantation of similar beta cell masses.

CONCLUSIONS/INTERPRETATION

The NOD-Rag1null Prf1null Ins2Akita mouse is the first immunodeficient, spontaneously hyperglycaemic mouse strain described that is based on the Ins2Akita mutation. This strain is suitable as hosts for human islet and human beta stem and progenitor cell transplantation in the absence of the need for pharmacological induction of diabetes. This strain of mice also has low levels of innate immunity and can be engrafted with a human immune system for the study of human islet allograft rejection.

Human C-peptide antagonises high glucose-induced endothelial dysfunction through the nuclear factor-kappaB pathway

AIMS/HYPOTHESIS

Endothelial dysfunction in diabetes is predominantly caused by hyperglycaemia leading to vascular complications through overproduction of oxidative stress and activation of the transcription factor nuclear factor-kappaB (NF-kappaB). Many studies have suggested that decreased circulating levels of C-peptide may play a role in diabetic vascular dysfunction. To date, the possible effects of C-peptide on endothelial cells and intracellular signalling pathways are largely unknown. We therefore investigated the effect of C-peptide on several biochemical markers of endothelial dysfunction in vitro. To gain insights into potential intracellular signalling pathways affected by C-peptide, we tested NF-kappaB activation, since it is known that inflammation, secondary to oxidative stress, is a key component of vascular complications and NF-kappaB is a redox-dependent transcription factor.

METHODS

Human aortic endothelial cells (HAEC) were exposed to 25 mmol/l glucose in the presence of C-peptide (0.5 nmol/l) for 24 h and tested for expression of the gene encoding vascular cell adhesion molecule-1 (VCAM-1) by RT-PCR and flow cytometry. Secretion of IL-8 and monocyte chemoattractant protein-1 (MCP-1) was measured by ELISA. NF-kappaB activation was analysed by immunoblotting and ELISA.

RESULTS

Physiological concentrations of C-peptide affect high glucose-induced endothelial dysfunction by: (1) decreasing VCAM-1 expression and U-937 cell adherence to HAEC; (2) reducing secretion of IL-8 and MCP-1; and (3) suppressing NF-kappaB activation.

CONCLUSIONS/INTERPRETATION

During hyperglycaemia, C-peptide directly affects VCAM-1 expression and both MCP-1 and IL-8 HAEC secretion by reducing NF-kappaB activation. These effects suggest a physiological anti-inflammatory (and potentially anti-atherogenic) activity of C-peptide on endothelial cells.

Metabolic aspects of pig-to-monkey (Macaca fascicularis) islet transplantation: implications for translation into clinical practice

AIMS/HYPOTHESIS

Attempts to use an alternative source of islets to restore glucose homeostasis in diabetic patients require preclinical islet xenotransplantation models to be tested. These models raise questions about metabolic compatibility between species and the most appropriate metabolic parameters to be used to monitor graft function. The present study investigated and compared relevant gluco-metabolic parameters in pigs, monkeys and the pig-to-monkey islet transplantation model to gain insight into the potential clinical outcome of pig-to-human islet transplantation.

METHODS

Basal and IVGTT-stimulated blood glucose, C-peptide, insulin and glucagon levels were assessed in non-diabetic pigs and monkeys. The same parameters were used to evaluate the performance of porcine islet xenografts in diabetic monkeys.

RESULTS

Non-diabetic cynomolgus monkeys showed lower levels of fasting and stimulated blood glucose but higher levels of C-peptide and insulin than non-diabetic pigs. The reported levels in humans lie between those of monkeys and pigs, and differences in metabolic parameters between pigs and humans appear to be smaller than those between pigs and cynomolgus monkeys. The transplantation data indicated that the degree of graft function (evaluated by the measurement of C-peptide levels) necessary to normalise blood glucose in the recipient was determined by the recipient levels rather than by the donor levels.

CONCLUSIONS/INTERPRETATION

The differences between donor and recipient species may affect the transplantation outcome and need to be considered when assessing graft function in xenotransplantation models. Given the differences between monkeys and humans as potential recipients of pig islets, it should be easier to reach glucose homeostasis in pig-to-human than in pig-to-non-human primate islet xenotransplantation.