Ferritin heavy chain supports stability and function of the regulatory T cell lineage

Regulatory T (TREG) cells develop via a program orchestrated by the transcription factor forkhead box protein P3 (FOXP3). Maintenance of the TREG cell lineage relies on sustained FOXP3 transcription via a mechanism involving demethylation of cytosine-phosphate-guanine (CpG)-rich elements at conserved non-coding sequences (CNS) in the FOXP3 locus. This cytosine demethylation is catalyzed by the ten-eleven translocation (TET) family of dioxygenases, and it involves a redox reaction that uses iron (Fe) as an essential cofactor. Here, we establish that human and mouse TREG cells express Fe-regulatory genes, including that encoding ferritin heavy chain (FTH), at relatively high levels compared to conventional T helper cells. We show that FTH expression in TREG cells is essential for immune homeostasis. Mechanistically, FTH supports TET-catalyzed demethylation of CpG-rich sequences CNS1 and 2 in the FOXP3 locus, thereby promoting FOXP3 transcription and TREG cell stability. This process, which is essential for TREG lineage stability and function, limits the severity of autoimmune neuroinflammation and infectious diseases, and favors tumor progression. These findings suggest that the regulation of intracellular iron by FTH is a stable property of TREG cells that supports immune homeostasis and limits the pathological outcomes of immune-mediated inflammation.

Proteomics reveals unique identities of human TGF-β-induced and thymus-derived CD4+ regulatory T cells

The CD4⁺ regulatory T (Treg) cell lineage, defined by FOXP3 expression, comprises thymus-derived (t)Treg cells and peripherally induced (p)Treg cells. As a model for Treg cells, studies employ TGF-β-induced (i)Treg cells generated from CD4⁺ conventional T (Tconv) cells in vitro. Here, we describe how human iTreg cells relate to human blood-derived tTreg and Tconv cells according to proteomic analysis. Each of these cell populations had a unique protein expression pattern. iTreg cells had very limited overlap in protein expression with tTreg cells, regardless of cell activation status and instead shared signaling and metabolic proteins with Tconv cells. tTreg cells had a uniquely modest response to CD3/CD28-mediated stimulation. As a benchmark, we used a previously defined proteomic signature that discerns ex vivo naïve and effector Treg cells from Tconv cells and includes conserved Treg cell properties. iTreg cells largely lacked this Treg cell core signature and highly expressed e.g. STAT4 and NFATC2, which may contribute to inflammatory responses. We also used a proteomic signature that distinguishes ex vivo effector Treg cells from Tconv cells and naïve Treg cells. iTreg cells contained part of this effector Treg cell signature, suggesting acquisition of pTreg cell features. In conclusion, iTreg cells are distinct from tTreg cells and share limited features with ex vivo Treg cells at the proteomic level.

Regulatory T cell features in chronic granulomatous disease

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by mutations in any of the genes encoding the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system, responsible for the production of reactive oxygen species (ROS). CGD is marked by invasive bacterial and fungal infections and by autoinflammation/autoimmunity, of which the exact pathophysiology remains elusive. Contributing factors include decreased neutrophil apoptosis, impaired apoptotic neutrophil clearance, increased proinflammatory protein expression and reduced ROS-mediated inflammasome dampening. We have explored a fundamentally different potential mechanism: it has been reported that macrophage-mediated induction of regulatory T cells (T_regs ) depends on ROS production. We have investigated whether numerical or functional deficiencies exist in T_regs of CGD patients. As the prevalence of autoinflammation/autoimmunity differs between CGD subtypes, we have also investigated T_regs from gp91^phox -, p47^phox - and p40^phox -deficient CGD patients separately. Results show that T_reg numbers and suppressive capacities are not different in CGD patients compared to healthy controls, with the exception that in gp91^phox -deficiency effector T_reg (eT_reg ) numbers are decreased. Expression of T_reg markers CD25, inducible T cell co-stimulator (ICOS), Helios, cytotoxic T lymphocyte antigen 4 (CTLA-4) and glucocorticoid-induced tumor necrosis factor receptor (GITR) did not provide any clue for differences in T_reg functionality or activation state. No correlation was seen between eT_reg numbers and patients' clinical phenotype. To conclude, the only difference between T_regs from CGD patients and healthy controls is a decrease in circulating eT_regs in gp91^phox -deficiency. In terms of autoinflammation/autoimmunity, this group is the most affected. However, upon culture, patient-derived T_regs showed a normal phenotype and normal functional suppressor activity. No other findings pointed towards a role for T_regs in CGD-related autoinflammation/autoimmunity.

Protein array autoantibody profiles to determine diagnostic markers for neuropsychiatric systemic lupus erythematosus

Objective

The aim was to investigate the association between autoantibodies (autoAbs) and neuropsychiatric (NP) involvement in patients with SLE and to evaluate whether any autoAb or a combination of these autoAbs could indicate the underlying pathogenic process.

Methods

Using a multiplexed protein array for 94 antigens, we compared the serum autoAb profiles of 69 NPSLE patients, 203 SLE patients without NP involvement (non-NPSLE) and 51 healthy controls. Furthermore, we compared the profiles of NPSLE patients with clinical inflammatory (n = 38) and ischaemic (n = 31) NP involvement.

Results

In total, 75 IgG and 47 IgM autoAbs were associated with SLE patients in comparison with healthy controls. Comparing NPSLE with non-NPSLE and healthy control sera, 9 IgG (amyloid, cardiolipin, glycoprotein 2, glycoprotein 210, heparin, heparan sulphate, histone H2A, prothrombin protein and vimentin) and 12 IgM (amyloid, cardiolipin, centromere protein A, collagen II, histones H2A and H2B, heparan sulphate, heparin, mitochondrial 2, nuclear Mi-2, nucleoporin 62 and vimentin) autoAbs were present at significantly different levels in NPSLE. The combination of IgG autoAbs against heparan sulphate, histone H2B and vimentin could differentiate NPSLE from non-NPSLE (area under the curve 0.845, 99.97% CI: 0.756, 0.933; P < 0.0001). Compared with non-NPSLE, four IgG and seven IgM autoAbs were significantly associated with inflammatory NPSLE. In ischaemic NPSLE, three IgG and three IgM autoAbs were significantly different from non-NPSLE patients.

Conclusion

In our cohort, the presence of high levels of anti-heparan sulphate and anti-histone H2B combined with low levels of anti-vimentin IgG autoAbs is highly suggestive of NPSLE. These results need to be validated in external cohorts.

The TNF Receptor Superfamily-NF-κB Axis Is Critical to Maintain Effector Regulatory T Cells in Lymphoid and Non-lymphoid Tissues

After exiting the thymus, Foxp3⁺ regulatory T (Treg) cells undergo further differentiation in the periphery, resulting in the generation of mature, fully suppressive effector (e)Treg cells in a process dependent on TCR signaling and the transcription factor IRF4. Here, we show that tumor necrosis factor receptor superfamily (TNFRSF) signaling plays a crucial role in the development and maintenance of eTreg cells. TNFRSF signaling activated the NF-κB transcription factor RelA, which was required to maintain eTreg cells in lymphoid and non-lymphoid tissues, including RORγt⁺ Treg cells in the small intestine. In response to TNFRSF signaling, RelA regulated basic cellular processes, including cell survival and proliferation, but was dispensable for IRF4 expression or DNA binding, indicating that both pathways operated independently. Importantly, mutations in the RelA binding partner NF-κB1 compromised eTreg cells in humans, suggesting that the TNFRSF-NF-κB axis was required in a non-redundant manner to maintain eTreg cells in mice and humans.

Humoral Immunodeficiency with Hypotonia, Feeding Difficulties, Enteropathy, and Mild Eczema Caused by a Classical FOXP3 Mutation

We describe here the case of a boy who presented with pulmonary infections, feeding difficulties due to velopharyngeal insufficiency and gastroesophageal reflux, myopathy, and hypotonia soon after birth. Later, he was also found to have an elevated immunoglobulin (Ig) E and mild eczema and was diagnosed with inflammatory bowel disease. Further immunological screening at the age of 7 years showed low B and NK cell numbers but normal CD4⁺ and CD8⁺ T cells and notably, normal numbers of CD4⁺ regulatory T (Treg) cells. Serum IgG, IgA, and IgM were low to normal, but he had a deficient response to a pneumococcal polysaccharide vaccine and thus a humoral immunodeficiency. To our surprise, whole exome sequencing revealed a mutation in forkhead box protein 3 (FOXP3), encoding an essential transcription factor for the development and function of Treg cells. This classical mutation is associated with immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. Further in vitro studies indeed showed defective function of Treg cells despite normal FOXP3 protein expression and nuclear localization. The boy underwent hematopoietic stem cell transplantation at 11 years of age and despite the temporary development of diabetes while on prednisone is now doing much better, IgE levels have declined, and his fatigue has improved. This case illustrates that a classical pathogenic mutation in FOXP3 can lead to a clinical phenotype where the diagnosis of IPEX syndrome was never considered because of the lack of diabetes and the presence of only mild eczema, in addition to the normal Treg cell numbers and FOXP3 expression.

ADAR1 Facilitates HIV-1 Replication in Primary CD4+ T Cells

Unlike resting CD4⁺ T cells, activated CD4⁺T cells are highly susceptible to infection of human immunodeficiency virus 1 (HIV-1). HIV-1 infects T cells and macrophages without activating the nucleic acid sensors and the anti-viral type I interferon response. Adenosine deaminase acting on RNA 1 (ADAR1) is an RNA editing enzyme that displays antiviral activity against several RNA viruses. Mutations in ADAR1 cause the autoimmune disorder Aicardi-Goutieères syndrome (AGS). This disease is characterized by an inappropriate activation of the interferon-stimulated gene response. Here we show that HIV-1 replication, in ADAR1-deficient CD4⁺T lymphocytes from AGS patients, is blocked at the level of protein translation. Furthermore, viral protein synthesis block is accompanied by an activation of interferon-stimulated genes. RNA silencing of ADAR1 in Jurkat cells also inhibited HIV-1 protein synthesis. Our data support that HIV-1 requires ADAR1 for efficient replication in human CD4⁺T cells.

Phenotypic variation in Aicardi-Goutières syndrome explained by cell-specific IFN-stimulated gene response and cytokine release

Aicardi-Goutières syndrome (AGS) is a monogenic inflammatory encephalopathy caused by mutations in TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, ADAR1, or MDA5. Mutations in those genes affect normal RNA/DNA intracellular metabolism and detection, triggering an autoimmune response with an increase in cerebral IFN-α production by astrocytes. Microangiopathy and vascular disease also contribute to the neuropathology in AGS. In this study, we report that AGS gene silencing of TREX1, SAMHD1, RNASEH2A, and ADAR1 by short hairpin RNAs in human neural stem cell-derived astrocytes, human primary astrocytes, and brain-derived endothelial cells leads to an antiviral status of these cells compared with nontarget short hairpin RNA-treated cells. We observed a distinct activation of the IFN-stimulated gene signature with a substantial increase in the release of proinflammatory cytokines (IL-6) and chemokines (CXCL10 and CCL5). A differential impact of AGS gene silencing was noted; silencing TREX1 gave rise to the most dramatic in both cell types. Our findings fit well with the observation that patients carrying mutations in TREX1 experience an earlier onset and fatal outcome. We provide in the present study, to our knowledge for the first time, insight into how astrocytic and endothelial activation of antiviral status may differentially lead to cerebral pathology, suggesting a rational link between proinflammatory mediators and disease severity in AGS.

Brain perihematoma genomic profile following spontaneous human intracerebral hemorrhage

Background

Spontaneous intracerebral hemorrhage (ICH) represents about 15% of all strokes and is associated with high mortality rates. Our aim was to identify the gene expression changes and biological pathways altered in the brain following ICH.

Methodology/Principal Findings

Twelve brain samples were obtained from four deceased patients who suffered an ICH including perihematomal tissue (PH) and the corresponding contralateral white (CW) and grey (CG) matter. Affymetrix GeneChip platform for analysis of over 47,000 transcripts was conducted. Microarray Analysis Suite 5.0 was used to process array images and the Ingenuity Pathway Analysis System was used to analyze biological mechanisms and functions of the genes. We identified 468 genes in the PH areas displaying a different expression pattern with a fold change between −3.74 and +5.16 when compared to the contralateral areas (291 overexpressed and 177 underexpressed). The top genes which appeared most significantly overexpressed in the PH areas codify for cytokines, chemokines, coagulation factors, cell growth and proliferation factors while the underexpressed codify for proteins involved in cell cycle or neurotrophins. Validation and replication studies at gene and protein level in brain samples confirmed microarray results.

Conclusions

The genomic responses identified in this study provide valuable information about potential biomarkers and target molecules altered in the perihematomal regions.

Irinotecan-Cetuximab-Bevacizumab as a Salvage Treatment in Heavily Pretreated Metastatic Colorectal Cancer Patients: A Retrospective Observational Study

<i>Background:</i> The objective was to evaluate the efficacy of irinotecan-cetuximab-bevacizumab in combination as a salvage treatment for heavily pretreated metastatic colorectal cancer patients. <i>Methods:</i> A total of 39 patients resistant to both oxaliplatin and irinotecan were included in this retrospective study. Treatment consisted of irinotecan 180/m² every 14 days, weekly cetuximab standard dose and bevacizumab 5 mg/kg every 14 days. <i>Results:</i> Partial response was observed in 8 patients (20%), stable disease in 24 (61%) and progressive disease in 7 (18%). Overall response rate in KRAS wild type was 6/22 (27%) and in mutated KRAS it was 2/15 (13%). Median time to progression was 8 months (6.4–9.4) and median overall survival 12 months (10.1–13.8). Overall, grade 3–4 adverse events were observed in 24 patients (62%). <i>Conclusions:</i> This regimen is active and moderately well tolerated in heavily pretreated advanced colorectal patients. However, caution is advisable when interpreting these results, because they run against the findings of two large phase III trials.

Increased intranuclear matrix metalloproteinase activity in neurons interferes with oxidative DNA repair in focal cerebral ischemia

Increased matrix metalloproteinase (MMP) activity is implicated in proteolysis of extracellular matrix in ischemic stroke. We recently observed intranuclear MMP activity in ischemic brain neurons at early reperfusion, suggesting a possible role in nuclear matrix proteolysis. Nuclear proteins, poly-ADP-ribose polymerase-1 (PARP-1) and X-ray cross-complementary factor 1 (XRCC1), as well as DNA repair enzymes, are important in DNA fragmentation and cell apoptosis. We hypothesized that intranuclear MMP activity facilitates oxidative injury in neurons during early ischemic insult by cleaving PARP-1 and XRCC1, interfering with DNA repair. We induced a 90-min middle cerebral artery occlusion in rats. Increase activity of MMP-2 and -9, detected in the ischemic neuronal nuclei at 3 h, was associated with DNA fragmentation at 24 and 48 h reperfusion. The intranuclear MMPs cleaved PARP-1. Treatment of the rats with a broad-spectrum MMP inhibitor, BB1101, significantly attenuated ischemia-induced PARP-1 cleavage, increasing its activity. Degradation of XRCC1 caused by ischemic insult in rat brain was also significantly attenuated by BB1101. We found elevation of oxidized DNA, apurinic/apyrimidinic sites, and 8-hydroxy-2'-deoxyguanosine, in ischemic brain cells at 3 h reperfusion. BB1101 markedly attenuated the early increase of oxidized DNA. Using tissue from stroke patients, we found increased intranuclear MMP expression. Our data suggest that intranuclear MMP activity cleaves PARP-1 and XRCC1, interfering with oxidative DNA repair. This novel role for MMPs could contribute to neuronal apoptosis in ischemic injuries.

Vascular MMP-9/TIMP-2 and neuronal MMP-10 up-regulation in human brain after stroke: a combined laser microdissection and protein array study

Matrix Metalloproteinases (MMPs) play an important role in brain injury after ischemic stroke. In the present study, we aimed to assess the global expression of MMP-Family proteins in the human brain after stroke by using a combination of Searchlight Protein Array and Laser Microdissection to determine their cellular origin. This study demonstrated that MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, MMP-10, MMP-13, and TIMP-1 were upregulated in the infarcted tissue compared to healthy control areas. Using laser microdissection we obtained specific neuronal and vascular populations from both infarcted and control areas. From these fractions, we showed that MMP-9 and TIMP-2 were highly produced in brain microvessels while MMP-10 was notably increased in neurons of the ischemic brain but not in healthy areas. These findings demonstrate a selective cell-dependent MMP secretion, opening the possibility of selectively targeting specific MMPs for neuroprotection or vasculoprotection following stroke.

Endogenous activated protein C predicts hemorrhagic transformation and mortality after tissue plasminogen activator treatment in stroke patients

BACKGROUND

Activated protein C (APC) is a plasma serine protease with systemic anticoagulant and a wide spectrum of cytoprotective activities that has been proposed as a promising therapy for acute stroke. Therefore, we sought to investigate the role of endogenous APC in human ischemic stroke.

METHODS

Our target were 119 consecutive patients with an ischemic stroke involving the middle cerebral artery territory who received tissue plasminogen activator (t-PA) within 3 h of symptom onset. APC was measured before, as well as 1 and 2 h after t-PA administration, and again at 12 and 24 h after stroke onset. Cranial tomography scan was obtained at admission and repeated at 24-48 h or when a neurological worsening occurred to rule out the presence of hemorrhagic complications. The functional outcome was evaluated by 3-month modified Rankin Scale.

RESULTS

A total of 117 t-PA-treated patients were finally included in the analyses. APC peaked at 1 h after t-PA administration (pretreatment APC = 132.44 +/- 36.39%, 1-hour APC = 184.20 +/- 34.28%, 2-hour APC = 145.50 +/- 35.23%; p < 0.0001). Interestingly, a high 2-hour APC level was associated with parenchymal hemorrhages (OR = 25.19; 95% CI = 4.76-133.19; p = 0.0001) and mortality (OR = 13.8; 95% CI = 2.58-73.63; p = 0.001), in a logistic regression model. Our results remained significant after Bonferroni correction for multiple testing.

CONCLUSIONS

A high endogenous APC level 2 h after t-PA administration is independently associated with hemorrhagic transformation and mortality in our cohort of stroke patients. Establishing any causal link for these relationships needs further research.

Matrix metalloproteinase-13 is activated and is found in the nucleus of neural cells after cerebral ischemia

Matrix metalloproteinases (MMPs) have been implicated in the pathophysiology of ischemic stroke. In this study, we investigated the time course of gelatinolytic activation in a rat model of permanent ischemia. We observed an activation of MMPs as early as 30 mins after the ischemic insult, mainly in the nuclei of brain cells. Besides, we explored MMP-13 expression in brain samples of the animal model and stroke deceased patients. We observed an upregulation of active MMP-13 in rat brains (P<0.05) after 90 mins of cerebral ischemia. Human infarct/periinfarct samples also showed higher levels of active MMP-13 (P<0.05) compared with contralateral ones. Interestingly, we found that MMP-13 colocalized with 46-diamidino-2-phenyl indole signal by immunohistochemistry in both humans and rats, suggesting an intranuclear localization for MMP-13. Immunohistochemistry also revealed that MMP-13 was mainly produced by neurons, in both species, but also by oligodendrocytes in rats, and by astrocytes in humans. Finally we subjected a rat primary neuronal culture to oxygen and glucose deprivation (OGD) and we reproduced the nuclear translocation of MMP-13 in vitro. Nuclear extracts from cells confirmed upregulation of active MMP-13 after OGD (P<0.05). These results suggest that MMP-13 activation and its nuclear translocation is an early consequence of an ischemic stimulus.

Monocyte count is an underlying marker of lacunar subtype of hypertensive small vessel disease

BACKGROUND

In the hypertensive small vessel disease (HSVD), it remains unclear why some patients develop lacunar infarcts (LIs) whilst others develop deep intracerebral hemorrhages (dICHs). Inflammation might be related to LI, and leukocyte and monocyte counts are regarded as an inflammatory marker of ischemic stroke.

OBJECTIVE

We investigated the relationship between leukocyte and monocyte counts determined in the first 24 h after stroke onset in HSVD patients.

METHODS

We prospectively studied 236 patients with first acute stroke because of HSVD (129 LI and 107 dICH). We analyzed demographic data, vascular risk factors, and white blood cell count subtypes obtained in the first 24 h after stroke.

RESULTS

The multivariate analysis showed that LI subtype of HSVD was correlated with hyperlipidemia (P < 0.0001), a higher monocyte count (P = 0.002), and showed a trend with current smoking (P = 0.051), whereas dICH subtype was correlated with low serum total cholesterol (P = 0.003), low serum triglycerides (P < 0.0001), and high neutrophil count (P = 0.050).

CONCLUSIONS

In patients who developed HSVD-related stroke, high monocyte count, current smoking, and hyperlipidemia are prothrombotic factors related to LI, whereas low cholesterol and triglyceride values are related to dICH. Monocyte count might be an inflammatory risk marker for the occlusion of small vessels in hypertensive patients.

Tissue plasminogen activator (t-PA) promotes neutrophil degranulation and MMP-9 release

Recombinant tissue plasminogen activator (t-PA), the only approved stroke treatment, is used for clot lysis within the occluded brain artery. Unfortunately, matrix metalloproteinase-9 (MMP-9) concentration increases after t-PA treatment and has been related to hemorrhagic transformation after ischemic stroke. Although the exact cellular source of brain MMP-9 remains unknown, invading, inflammatory cells, such as neutrophils, release MMP-9 to cross the blood brain barrier. Therefore, we hypothesize that the most feared side effect of stroke reperfusion therapy, brain hemorrhage, is related to t-PA-induced MMP-9 release by neutrophils. We show by means of ELISA that t-PA treatment promotes MMP-9, MMP-8, and tissue inhibitor metalloproteinase-2 release from human neutrophils ex vivo within 10 and 30 min. Moreover, by zymography and Western blot, we observed that neutrophils are emptied of MMP-9 content after t-PA treatment at those times. Finally, total internal reflection fluorescent imaging allowed us to observe the t-PA effect on neutrophils, showing the promotion of degranulation on these cells in vivo. Our data suggest that neutrophils are good candidates to be the main source of MMP-9 following t-PA stroke treatment and in consequence, partially responsible for thrombolysis-related brain bleedings.

MMP-9–Positive Neutrophil Infiltration Is Associated to Blood–Brain Barrier Breakdown and Basal Lamina Type IV Collagen Degradation During Hemorrhagic Transformation After Human Ischemic Stroke

Background and Purpose— An abnormal expression of some matrix metalloproteinases (MMPs) is related with hemorrhagic transformation events after stroke. Our aim was to investigate MMP-2 and MMP-9 in the ischemic brain and its relation with blood–brain barrier breakdown after hemorrhagic transformation in human stroke.

Methods— We assessed 5 cases of fatal ischemic strokes with hemorrhagic complications; brain samples were obtained from infarct, hemorrhagic, and contralateral tissue. MMP-9 and MMP-2 content was analyzed by zymography and immunohistochemistry was performed to localize MMP-9 and to assess collagen IV integrity in the basal lamina. Laser capture microdissection was performed to isolate blood–brain barrier vessels to study these MMPs.

Results— Overall, MMP-9 levels were higher both in hemorrhagic and nonhemorrhagic infarcted tissue compared to contralateral areas ( P <0.0001 and P <0.05). Moreover, levels of the cleaved MMP-9 85kDa-form were significantly elevated in the hemorrhagic compared to nonhemorrhagic and contralateral areas ( P =0.033 and P <0.0001). No changes were found for MMP-2 content. Immunostaining revealed a strong MMP-9–positive neutrophil infiltration surrounding brain microvessels associated with severe basal lamina type IV collagen degradation and blood extravasation. Microdissection confirmed that content of MMP-9 was similarly high in microvessel endothelium from hemorrhagic and infarcted areas compared to contralateral hemisphere vessels ( P <0.05), pointing to neutrophils surrounding dissected microvessels as the main source of MMP-9 in hemorrhagic areas.

Conclusions— Our results show a strong neutrophil infiltration in the infarcted and hemorrhagic areas with local high MMP-9 content closely related to basal lamina collagen IV degradation and blood–brain barrier breakdown. Microvessel and inflammatory MMP-9 response are associated with hemorrhagic complications after stroke.

Brain contusions induce a strong local overexpression of MMP-9. Results of a pilot study

BACKGROUND

Brain contusions are inflammatory evolutive lesions that induce intracranial pressure increase and edema, contributing to neurological outcome. Matrix metalloproteinases (MMPs) 2 and 9 can degrade the majority of the extracellular matrix components, and are implicated in blood-brain barrier disruption and edema formation. The aim of this study was to investigate MMP-2 and MMP-9 profiles in human brain contusions using zymography.

METHODS

A prospective study was conducted in 20 traumatic brain injury patients where contusion brain tissue was resected. Brain tissues from lobectomies were used as controls. Brain homogenates were analysed by gelatin zymography and in situ zimography was performed to confirm results, on one control and one brain contusion tissue sample.

FINDINGS

MMP-2 and MMP-9 levels were higher in brain contusions when compared to controls. MMP-9 was high during the first 24 hours and at 48 to 96 hours, whereas MMP-2 was slightly high at 24 to 96 hours. In situ zymography confirmed gelatin zymography results. A relation between outcome and MMP-9 levels was found; MMP-9 levels were higher in patients with worst outcome.

CONCLUSIONS

Our results indicate strong time-dependent gelatinase expression primarily from MMP-9, suggesting that the inflammatory response induced by focal lesions should be considered as a new therapeutic target.

Leukaemia inhibitory factor is over-expressed by ischaemic brain tissue concomitant with reduced plasma expression following acute stroke

Leukaemia inhibitory factor (LIF) is a glycoprotein of the interleukin-6 family, which has potent pro-inflammatory properties and is involved in regulation of neuronal differentiation. We have previously identified its upregulation in gene microarrays following acute ischaemic stroke in man. LIF expression and localization was measured in human ischaemic stroke autopsy specimens, in a rat model of middle cerebral artery occlusion (MCAO) and in human foetal neural cell cultures following oxygen-glucose deprivation (OGD) by Western blotting and immunohistochemistry. Circulating LIF was determined in the plasma of patients in the hyper-acute stroke phase using a multiplex enzyme-linked-immunosorbent serologic assay system. Patients demonstrated an increase in LIF expression in peri-infarcted regions with localization in neurons and endothelial cells of microvessels surrounding the infarcted core. The rat MCAO model showed similar upregulation in neurons with a peak increase at 90 min. Circulating serum LIF expression was significantly decreased in the hyper-acute phase of stroke. Brain-derived neurons and glia cultured in vitro demonstrated an increase in gene/protein and protein expression respectively following exposure to OGD. Increased LIF expression in peri-infarcted regions and sequestration from the peripheral circulation in acute stroke patients are characteristic of the pathobiological response to ischaemia and tissue damage.

[The therapeutic potential of endothelial progenitor cells in ischaemic stroke]

AIM

To review the present knowledge about endothelial progenitor cells (EPCs), their relationship with stroke and their possible therapeutic potential.

DEVELOPMENT

Activation of angiogenesis and vasculogenesis after cerebral ischemia is an attempt to recover damaged cerebral tissue. The role of EPCs in angiogenesis/vasculogenesis after brain ischemia remains unknown. Many studies have been published about the isolation, phenotyping and function of EPCs. However, there is not a unique definition for these cells; their origin and function are still an issue of controversy between different research groups. In this review, we summarize the currently used techniques and the most relevant publications about EPCs in experimental models of cerebral ischemia and their role in stroke.

CONCLUSIONS

The identification of EPCs in peripheral blood as hematopoietic cells with the ability to differentiate into endothelial cells, broke the paradigm that vasculogenesis was only an embryogenic process. However, better knowledge about the origin and function of EPCs in cerebral ischemia is required. Stimulation of these cells opens a wide new field of cell-based angiogenic therapy that could improve the current stroke treatment.

[Laser capture microdissection: a new tool for the study of cerebral ischemia]

AIM

To review studies using microscopy techniques of laser capture microdissection on cerebral tissue and the possible applications of this methodology for the study of cerebral ischemia.

DEVELOPMENT

Since ischemic stroke induces neuronal death following the occlusion of a brain artery, reperfusion and neuroprotective treatments are the only therapeutic strategies used so far. However, the relevant role of other brain cells such as astrocytes, oligodendrocytes, microglial and endothelial cells, or even the extracellular matrix itself, in several steps of the ischemic cascade, adds a huge complexity to stroke. In this scenario lesser simplistic approaches will be required. Therefore, the individual study of all cellular populations involved in cerebral ischemia seems mandatory to determine the cellular source of all participant molecules. Laser capture microdissection appears as a rapid, efficient and precise technique to isolate cell populations for further analysis of gene expression or proteomics.

CONCLUSIONS

Laser capture microdissection is a useful and reliable technique to obtain specific cell groups that might guide us to distinguish the cellular origin of the main molecules that are involved in the different steps of the ischemic cascade.

Genes related to iron metabolism and susceptibility to Alzheimer's disease in Basque population

Alzheimer's disease (AD) is the most common dementing disorder and presents with a progressive and irreversible cognitive decline of gradual onset. To date, several reports have involved iron in AD physiopathology. In this study, we have analysed TFC2 variant and HFE mutations (H63D and C282Y) in 211 AD patients and 167 controls recruited from an area of the Basque Country. Furthermore, we have studied APOE genotype as it is a well-known risk factor for AD. APOE epsilon 4 allele was associated with an increased risk of AD and an earlier age at onset, whereas no association was found between TFC2 or HFE C282Y mutation and disease susceptibility. The frequency of H63D mutation was higher in control population (29.9%) than in AD patients (18%), suggesting a protective role of this allele on AD either due to the presence of the mutation itself or through the effect of other related genes in the ancestral haplotype in which it is included.

HLA-A*2402 and a microsatellite (D6S248) are secondary independent susceptibility markers to ankylosing spondylitis in basque patients

Ankylosing spondylitis (AS) is universally associated with human leukocyte antigen B27 (HLA-B27), although other genes could determine the development and clinical expression of the disease. HLA-A9 (A*2402) allele was previously found to be associated in Basque patients. The objective of this study is to perform a more precise analysis of microsatellite polymorphisms in HLA-A*2402 and B27 haplotypes to elucidate the significance of this association. A group of 50 unrelated AS patients and 113 controls of Basque origin were studied. Eight microsatellites in the class I major histocompatibility complex region with vicinity to HLA-A and -B were analyzed and the strength of allelic associations to AS and linkage disequilibrium (LD) between alleles were evaluated. Allele 15 at the microsatellite locus D6S248, 1000 Kb telomeric to HLA-A showed a strong positive association with the disease (OR:6; pc=4.7x10(-4)) and it could not be explained by LD to HLA-B27, HLA-A*2402 or any other loci. We found that D6S248-15 allele together with HLA-A*2402 could be B27-independent markers of additional susceptibility gene/s localised in the region telomeric to HLA-A in Basque AS patients.

HFE gene mutations analysis in Basque hereditary haemochromatosis patients and controls

C282Y/C282Y genotype is the prevalent genotype in Hereditary Haemochromatosis (HH), however, other genotypes have been associated with the disease. The objective of our study was to analyse the frequency of the three main mutations of HFE gene in HH patients and controls from the Basque population with differential genetic characteristics. Thirty five HH patients and 116 controls were screened for C282Y, H63D and S65C mutations using a PCR-RFLP technique. The association of HLA-A and-B alleles and HFE mutations was also studied in Basque controls. The frequency of C282Y homozygotes in the group of patients was only 57%. The rest of the patients presented heterogeneous genotypes, including compound heterozygotes: 11% of them were C282Y/H63D; and 2.85% were H63D/S65C. H63D or S65C heterozygotes had a frequency of 11% and 2.85 respectively and 5.71% patients lacked any mutation The high frequency of H63D in the healthy Basque population is confirmed in this study. A considerable incidence of S65C is observed either in controls and in HH (3%) or in iron overloaded patients. The peculiar genetic characteristics of Basques could explain the heterogeneity of genotypes in HH patients of this group. Further studies should be carried out to confirm these findings although the implication of other genetic or external factors in the development of HH is suggested.

Mixed cryoglobulinaemia in patients with chronic hepatitis C infection: prevalence, significance and relationship with different viral genotypes

In order to analyse the prevalence and significance of cryoglobulinaemia in patients with chronic hepatitis C virus (HCV) infection and the possible relationship of cryoglobulinaemia with the genotypes of HCV, we studied 89 patients with chronic HCV infection, 42 healthy controls and 22 patients with alcoholic cirrhosis. The patients with HCV were divided into three different groups according to the presence of cirrhosis and alanine aminotransferase levels. Moreover, in 20 patients with HCV and cryoglobulinaemia, HCV RNA sequences were quantified in serum and in cryoprecipitate. Cryoglobulins were detected more frequently in patients with chronic HCV infection than in healthy controls (42.6% vs. 4.7%; P<0.0001). Cryoglobulins were present in 68.4% of patients with HCV-related cirrhosis, which was nearly twice the figure in noncirrhotic HCV-infected patients and alcoholic cirrhotic patients. There were no differences in age, sex, aminotransferase levels or HCV genotype distribution in HCV-infected patients with or without cryoglobulinaemia. Only 13% of patients with chronic HCV infection and cryoglobulins showed symptoms of cryoglobulinaemia. There was a linear association between HCV RNA concentration in sera and in cryoprecipitates (P<0.0005). Patients with chronic HCV infection had a high prevalence of cryoglobulinaemia, especially in advanced forms of the disease, but clinical findings are few. There was no relationship with the genotype of HCV. The presence of HCV RNA in cryoprecipitates supported the hypothesis on the aetiological role of HCV in mixed cryoglobulinaemia.

HLA-A*9, a probable secondary susceptibility marker to ankylosing spondylitis in Basque patients

HLA-B27 is strongly associated to ankylosing spondylitis (AS). The objective of our study was to analyze HLA-B27 association, B27 subtype distribution and frequency of other HLA class I and DR antigens in a group of Basque AS patients. HLA class I antigens were typed serologically and HLA-B27 and A9 subtypes were determined by DNA typing in samples from 46 patients with AS, 54 B27-positive spondyloarthropathies, 82 healthy subjects and 20 B27-positive controls. A class I HLA 9.2 kb PvuII restriction fragment length polymorphism (RFLP), previously associated with AS, was analyzed in a representative group of patients and controls. We found that HLA-B*2705 conferred a relative risk of 126 for AS in this group. HLA-A9 (A*2402) allele was significantly increased in AS patients compared with healthy controls and B27-positive control group (Pcorr<0.0001) and also increased in patients affected with peripheral arthritis. No association between class I HLA 9.2 Kb RFLP and AS was found. These results suggest that HLA-A*9 allele itself or another linked gene could act as a secondary and independent susceptibility allele to AS.

Bacterial translocation and T-lymphocyte populations in experimental short-bowel syndrome

Bacterial translocation (BT) accounts in part for sepsis in short-bowel syndrome in which total parenteral nutrition (TPN) is routinely necessary. TPN "per se" facilitates BT and it has been suggested that decreased T-lymphocyte populations (TLP) in newborn rabbits and nude mice promote BT as well. We have tested the hypothesis that BT and modifications in TLP are to be expected in rats subjected to TPN and gut resection. Forty-five adult Wistar rats underwent central venous cannulations and were randomly assigned to one of three groups receiving for ten days three treatment regimes: - Group Sham (n = 17) oral intake of rat chow + saline (300 ml/kg/24 h) through a jugular vein catheter. - Group TPN (n = 17) fasting + infusion of all-in-one TPN solution (300 ml/kg/24 h). - Group RES (n = 11) fasting, same TPN regime + 80% gut resection. At the end of the experiment they were sacrified and specimens (peripheral and portal blood, spleen and mesenteric lymph nodes) were recovered, cultured and/or assessed for CD4+ and CD8+. Bacterial translocation was found in 47% of TPN animals, 92% of RES rats, but not in SHAM ones. Lymphocyte populations were not different in BT+ (n = 8) or BT- (n = 9) rats in the TPN group. TPN and resected animals showed a rise in CD4+ and a drop in CD8+ (then a better CD4+/CD8 ratio) when comparing with SHAM group rats. From this data we may conclude that: 1) BT is frequent if TPN is administered, and constant in resected animals. 2) No apparent relationship between the proportions of CD4+ and CD8+ lymphocytes and BT could be shown in TPN group. 3) High CD4+/CD8+ ratio in TPN and RES groups demonstrate that BT is possible even having good TLP.

Immune dysfunction in Down's syndrome: primary immune deficiency or early senescence of the immune system?

Multiple immunologic disturbances are commonly observed in individuals with Down's syndrome including abnormal proportions of peripheral blood lymphoid subsets, cellular dysfunction, and autoimmune phenomena. However, a majority of the individuals with this syndrome do not show clear features of immunological disease. Many of these immunological alterations are age-related changes and can be enclosed in the spectrum of multiple signs of early senescence characteristic of Down's syndrome.

Lymphocyte subpopulations after extensive small bowel resection in the rat

The increased risk of infection after massive intestinal resection (MIR) may be attributable to impaired nutrition, loss of intestinal lymphoid tissue, or both. This study examines whether MIR itself changes the immune cell populations in laboratory animals when nutritional status is preserved. The authors studied cellular immunity (lymphocyte subsets T4 and T8 and the T4:T8 ratio) and humoral immunity (IgG, IgM, IgA, and B lymphocytes) in the blood, spleen, and mesenteric lymph nodes of unresected Wistar rats (control group, n = 6) and of animals that underwent 80% bowel resection followed by 7 days of either oral feeding (resection-oral group, n = 6) or parenteral nutrition (resection-TPN group, n = 6). The increase in body weight was similar among all groups, and the levels of total protein, albumin, prealbumin, and immunoglobulin remained unchanged. All resected animals, irrespective of their feeding route, had significantly lower proportions of T4 and B lymphocytes and T4:T8 ratio in blood, T4 and T8 in mesenteric lymph nodes, and T4 and T4:T8 ratio in the spleen. The author's results suggest that removal of large amounts of lymphoid tissue along with the bowel during MIR might lead to inadequate immune response even when the nutritional status is preserved.

The contribution of the HLA-A, -B, -C and -DR, -DQ DNA typing to the study of the origins of Spaniards and Basques

The high polymorphism of the HLA system has been used as a powerful genetic tool to single out individuals and populations. By studying characteristic allele frequencies and extended HLA haplotypes in different populations, it is possible to identify ethnic groups and establish the genetic relationships among them. In the present study, HLA-A, -B, -C, -DR and -DQ typing at the serological/antigenic and the DNA level has been used for the first time to assign specific HLA frequencies and haplotypes to Spaniards and Basques and compare them with frequencies in other populations, particularly with North Africans. Allelic frequencies do not significantly differ between Spaniards and Basques. HLA genetic distances and their respective dendrogram together with the results on complete HLA haplotypes place Basques and Spaniards closer to paleo-North African populations than to other Europeans. This goes in favour of the Basques being a relative genetic isolate coming from the primitive Iberian/paleo-North African people. In addition, a tentative assignment of the most common Spanish HLA haplotypes to the different people who populated Iberia according to historical records has been done.

DNA staining changes associated with apoptosis and necrosis in blood lymphocytes of individuals with HIV infection

We used flow cytometry to quantitate cells that die by apoptosis or necrosis. The method uses low concentrations of two DNA binding dyes that allow one to establish selective regions for live, apoptotic, and necrotic cells in a rat thymocytes model. Quantitative analysis of blood lymphocyte death in individuals with HIV infection by this technique shows the presence of nonviable cells that exhibit a spectrum of changes in staining by DNA binding dyes. These changes range from typical features of cells undergoing programmed cell death or apoptosis to changes observed in cells that die by accidental death or necrosis. The proportion of cells exhibiting these lethal changes increases significantly in patients who progress to AIDS, but, although cells with staining features associated with apoptosis and necrosis were both found to be increased in in vitro-activated cells from AIDS patients, spontaneous in vivo activation preferentially leads to apoptotic changes without a significant increase of cells exhibiting the staining changes associated with necrosis.

An immunogenetic study of familial scleroderma

OBJECTIVE

To study the role of the HLA system in the genetic susceptibility to familial systemic sclerosis (SSc).

METHODS

HLA class I antigens were determined by classic serological methods and HLA-DRB, -DQA and -DQB genes were analysed by genetic typing in 36 individuals belonging to two families with several individuals affected by SSc.

RESULTS

The results did not show any association of the inheritance to SSc with any particular HLA allele in these families but revealed a striking frequency of ANA autoantibodies in healthy spouses of the members of these families.

CONCLUSION

The otherwise infrequent familial incidence of SSc does not appear to be primarily linked to the HLA system in this study but it is suggested that other unknown exogenous environmental factors could be implicated in the development of the disease in families.

Quantification of chicken alpha-fetoprotein: a useful tool in studies of embryo development and pathology

Chicken alpha-fetoprotein (AFP) from the plasma of 12-day-old chick embryos was purified by electroelution from SDS/PAGE gels, and used to produce polyclonal and monoclonal antibodies. Both reagents were then used to design a sandwich-type enzyme-immunoassay for the quantification of AFP in biological fluids. The assay was used to quantify AFP in the serum and amniotic fluid of chick embryos with abnormalities of the neural tube. Serum AFP was significantly greater in these embryos than in normal ones of similar age. Moreover, substantial amounts of AFP were demonstrated in the amniotic fluid, whereas this protein was undetectable in the amniotic fluid of normal embryos. This method of assay may provide a reliable tool for studies of chick embryogenesis and abnormalities of embryonal differentiation.

Imbalance of the CD4+ subpopulations expressing CD45RA and CD29 antigens in the peripheral blood of adults and children with Down syndrome

Peripheral blood lymphoid subsets expressing either CD45RA or CD29 antigens, were quantified in 30 children and 59 adults with Down Syndrome and appropriate age-matched controls, by dual immunofluorescence and flow cytometry. Down's patients, both adults and children, displayed a significant decrease of CD4+CD45RA+ cells in comparison with the observed in their age-matched controls, but no difference was found in the CD4+CD29+ subset. These results show clearly the imbalance of these subpopulations in the peripheral blood of individuals with Down syndrome that result in the inversion of the CD45RA/CD29 ratio, due to a major reduction of the CD45RA subset. No obvious difference was found in the CD45RA/CD29 ratio within the CD4 negative cells. Abnormalities of these subpopulations could be indicative of early senescence of the immune system, since age-related changes in Down's persons were in parallel with those observed in normal individuals and the proportion of both subpopulations were roughly similar in Down's children and normal adults.

[The defense against infection in the short bowel syndrome]

The high risk of infection in the short-bowel syndrome (SBS) may be due to malnutrition, lost of lymphoid bowel structures or both. Total parenteral nutrition (TPN) may alleviate the malnutrition, but we do not know what will happen with immune response in SBS with good nutritional state. We have studied the cellular immunity (lymphocytic subsets T4 and T8 and T4/T8 ratio) and the humoral one (IgG, IgM, IgA and B lymphocytes) in blood, spleen and mesenteric lymph nodes, in 12 wistar rats with 80% bowel resection, 6 of them with oral feeding and 6 with TPN, and 6 control rats, during 7 days. The weight increased and the total protein, albumin and prealbumin levels were the same in all groups. There was not difference between the resected groups. No difference was observed in the rate of immunoglobulins and the resected groups showed significatively lower figures than the control group in T4, B lymphocytes and T4/T8 ratio in blood, T4 and T8 in mesenteric nodes and in T4 and T4/T8 ratio in the spleen. These results suggest that the resection of large amounts of bowel could produce a fall in the immune response even when adequate nutritional state is preserved.