Columbia spotted frogs (Rana luteiventris) have characteristic skin microbiota that may be shaped by cutaneous skin peptides and the environment.

Global amphibian declines due to the fungal pathogen Batrachochytrium dendrobatidis (Bd) have led to questions about how amphibians defend themselves against skin diseases. A total of two amphibian defense mechanisms are antimicrobial peptides (AMPs), a component of amphibian innate immune defense and symbiotic skin bacteria, which can act in synergy. We characterized components of these factors in four populations of Columbia spotted frogs (Rana luteiventris) to investigate their role in disease defense. We surveyed the ability of their AMPs to inhibit Bd, skin bacterial community composition, skin metabolite profiles and presence and intensity of Bd infection. We found that AMPs from R. luteiventris inhibited Bd in bioassays, but inhibition did not correlate with Bd intensity on frogs. R. luteiventris had two prevalent and abundant core bacteria: Rhizobacter and Chryseobacterium. Rhizobacter relative abundance was negatively correlated with AMP's ability to inhibit Bd, but was not associated with Bd status itself. There was no relationship between metabolites and Bd. Bacterial communities and Bd differ by location, which suggests a strong environmental influence. R. luteiventris are dominated by consistent core bacteria, but also house transient bacteria that are site specific. Our emergent hypothesis is that host control and environmental factors shape the microbiota on R. luteiventris.

Analysis of the calcium paradox of renin secretion.

The secretion of the protease renin from renal juxtaglomerular cells is enhanced by subnormal extracellular calcium concentrations. The mechanisms underlying this atypical effect of calcium have not yet been unraveled. We therefore aimed to characterize the effect of extracellular calcium concentration on calcium handling of juxtaglomerular cells and on renin secretion in more detail. For this purpose, we used a combination of experiments with isolated perfused mouse kidneys and direct calcium measurements in renin-secreting cells in situ. We found that lowering of the extracellular calcium concentration led to a sustained elevation of renin secretion. Electron-microscopical analysis of renin-secreting cells exposed to subnormal extracellular calcium concentrations revealed big omega-shaped structures resulting from the intracellular fusion and subsequent emptying of renin storage vesicles. The calcium concentration dependencies as well as the kinetics of changes were rather similar for renin secretion and for renovascular resistance. Since vascular resistance is fundamentally influenced by myosin light chain kinase (MLCK), myosin light chain phosphatase (MLCP), and Rho-associated protein kinase (Rho-K) activities, we examined the effects of MLCK-, MLCP-, and Rho-K inhibitors on renin secretion. Only MLCK inhibition stimulated renin secretion. Conversely, inhibition of MCLP activity lowered perfusate flow and strongly inhibited renin secretion, which could not be reversed by lowering of the extracellular calcium concentration. Renin-secreting cells and smooth muscle cells of afferent arterioles showed immunoreactivity of MLCK. These findings suggest that the inhibitory effect of calcium on renin secretion could be explained by phosphorylation-dependent processes under control of the MLCK.

Type II diabetes and oral health: perceptions among adults with diabetes and oral/health care providers in Ghana.

OBJECTIVE: This study sought to examine oral health beliefs and attitudes, and utilisation of oral health care services among individuals with diabetes and health professionals who serve them in Ghana. BASIC RESEARCH DESIGN: A qualitative study using grounded theory was conducted. CLINICAL SETTING: University of Ghana Dental School at Korle Bu, University of Ghana School of Public Health, National Diabetes Research and Management Centre at Korle Bu, and New York University College of Dentistry. PARTICIPANTS: A convenience sample of 59 patients comprised 7 focus groups conducted in either Twi or English. Seven key informant interviews with healthcare professionals and one spiritual leader were completed. RESULTS: Data from the focus groups and interviews reveal: 1, half of the participants with diabetes have oral manifestations (e.g., bleeding gums) and participants are generally unaware of interrelationship between diabetes and oral health; 2, dental treatment utilisation is minimal and associated almost exclusively with reparative and emergency care; and 3, medical health providers do not acknowledge the interrelationship between oral health and diabetes nor do they incorporate oral health issues into diabetes screening/treatment. CONCLUSION: Oral health knowledge and practices are limited among patients with diabetes in Accra, Ghana. Collaborative efforts for in-service education and training for oral health and medical professionals may be beneficial in serving the oral and general health care needs as well as improving the oral health-related quality of life of Ghanaians with diabetes.

CD73/5'-ecto-nucleotidase acts as a regulatory factor in osteo-/chondrogenic differentiation of mechanically stimulated mesenchymal stromal cells.

Bone regeneration is influenced by mesenchymal stromal cells (MSCs) and mechanical conditions. How healing outcome and mechanical stability are linked on the cellular level, however, remains elusive. Cyclic-compressive loading of MSCs affects the expression of molecules involved in angiogenesis and matrix assembly, but also reduces the expression of CD73, an ecto-5'-nucleotidase, which plays a crucial role in extracellular adenosine generation. Although, for almost 20 years, CD73 has been a major cell surface marker defining MSCs, little is known about its function in these cells. Therefore, the aim of this study was to determine the putative involvement of CD73 in MSC differentiation after cyclic-compressive loading. After cultivation in appropriate differentiation media, chondrogenic differentiation ability was significantly increased in loaded MSCs, hence following current models. Through treatment with the CD73 inhibitor adenosine 5'-(α, ß-methylene) diphosphate, chondrogenic matrix deposition was further increased; in contrast, mineral matrix deposition and expression of osteogenic markers was reduced. One major signal transduction pathway, which is activated via CD73-mediated adenosine, is the adenosine receptor pathway. Thus, the adenosine receptor expression pattern was investigated. MSCs expressed the four known adenosine receptors at the mRNA level. After mechanical stimulation of MSCs, Adora2a was down-regulated. These data point towards a role of CD73 in MSC differentiation possibly via A2AR signalling, which is mutually regulated with CD73. In conclusion, the findings of this study suggest that CD73 is another regulatory factor in osteo-/chondrogenic differentiation of MSCs and may provide a - thus far underestimated - therapeutic target to guide bone regeneration.

Presymptomatic genetic testing in CADASIL.

Genetic counselling has been poorly investigated in cerebrovascular diseases. Characteristics, motivations and long-term outcome of presymptomatic tests (PT) in subjects at risk of CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy) were investigated at the National Centre for Rare Vascular Diseases of the Brain and/or Retina (CERVCO). Sociodemographic, motivational and psychological variables were collected between 2003 and 2010 for PT applicants. Multidisciplinary consultations (with a geneticist, neurologist and psychologist) were proposed over a 6 month period. When PT showed a deleterious mutation of the NOTCH3 gene, cognitive performances, mood, autonomy and quality of life were also assessed. Over 7 years, only 33 subjects asked for a PT of CADASIL. They were predominantly women, lived as a couple, had children and were of high sociocultural level. The dropout rate after the first step of the procedure was 63%. The characteristics of the 11 subjects who reached the end of the procedure did not differ from the 22 who dropped out. Six were carriers of the deleterious mutation and were still asymptomatic after a mean follow-up of 19 months. They did not experience any particular negative event and all of them indicated a high score of overall quality of life. Indeed, two carriers gave birth to their first child. These initial data in CADASIL show that PT is rarely requested and that there is a high dropout rate. Our study also highlights that a multidisciplinary and multistep procedure in genetic counselling testing appears useful to obtain minimal harmful consequences of genetic testing.

Cytomegalovirus-specific regulatory and effector T cells share TCR clonality--possible relation to repetitive CMV infections.

Cytomegalovirus (CMV) infections have a major impact on morbidity and mortality of transplant patients. Among the complex antiviral T-cell response, CMV-IE-1 antigen-specific CD8+ cells are crucial for preventing CMV disease but do not protect from recurring/lasting CMV reactivation. Recently, we confirmed that adoptive transfer of autologous IE-1/pp65-specific T-cell lines was able to combat severe CMV disease; however, the control of CMV infection was only temporary. We hypothesized that CMV-induced regulatory T cells (iTreg) might be related to recurring/lasting CMV infection. In fact, kidney transplant patients with recurring CMV infections expressed enhanced suppression on CMV response. Analysis of in vitro expanded CD4+ epitope-specific cells revealed that CMV-specific CD4+CD25(high) Treg cells functionally suppress CD25(low) effector T cells (Teff) upon epitope-specific reactivation. Their phenotype is similar to iTreg - CD39(high) /Helios-/IL-2(low) /IFNγ(high) /IL-10±/TGFß-LAP±/FOXP3+ and methylated foxp3 locus. Remarkably, in vitro expanded CD4+CD25(high) iTreg share the same dominant TCR-Vß-CDR3 clones with functionally distinct CD4+CD25(low) Teff. Moreover, the same clones were present in freshly isolated CD4+CD25(high) and CD4+CD25(low) T cells suggesting their in vivo generation. These findings directly demonstrate that Teff and iTreg can differentiate from one "mother" clone with specificity to the same viral epitope and indicate that peripheral iTreg generation is related to frequent antigen appearance.

Regulation of renin release by local and systemic factors.

The renin-angiotensin system (RAS) is critically involved in the regulation of the salt and volume status of the body and blood pressure. The activity of the RAS is controlled by the protease renin, which is released from the renal juxtaglomerular epithelioid cells into the circulation. Renin release is regulated in negative feedback-loops by blood pressure, salt intake, and angiotensin II. Moreover, sympathetic nerves and renal autacoids such as prostaglandins and nitric oxide stimulate renin secretion. Despite numerous studies there remained substantial gaps in the understanding of the control of renin release at the organ or cellular level. Some of these gaps have been closed in the last years by means of gene-targeted mice and advanced imaging and electrophysiological methods. In our review, we discuss these recent advances together with the relevant previous literature on the regulation of renin release.

CD73 and CD29 concurrently mediate the mechanically induced decrease of migratory capacity of mesenchymal stromal cells.

e assumption that mesenchymal stromal cell (MSC)-based-therapies are capable of augmenting physiological regeneration processes has fostered intensive basic and clinical research activities. However, to achieve sustained therapeutic success in vivo, not only the biological, but also the mechanical microenvironment of MSCs during these regeneration processes needs to be taken into account. This is especially important for e.g., bone fracture repair, since MSCs present at the fracture site undergo significant biomechanical stimulation. This study has therefore investigated cellular characteristics and the functional behaviour of MSCs in response to mechanical loading. Our results demonstrated a reduced expression of MSC surface markers CD73 (ecto-5'-nucleotidase) and CD29 (integrin ß1) after loading. On the functional level, loading led to a reduced migration of MSCs. Both effects persisted for a week after the removal of the loading stimulus. Specific inhibition of CD73/CD29 demonstrated their substrate dependent involvement in MSC migration after loading. These results were supported by scanning electron microscopy images and phalloidin staining of actin filaments displaying less cell spreading, lamellipodia formation and actin accumulations. Moreover, focal adhesion kinase and Src-family kinases were identified as candidate downstream targets of CD73/CD29 that might contribute to the mechanically induced decrease in MSC migration. These results suggest that MSC migration is controlled by CD73/CD29, which in turn are regulated by mechanical stimulation of cells. We therefore speculate that MSCs migrate into the fracture site, become mechanically entrapped, and thereby accumulate to fulfil their regenerative functions.

Verbal memory impairment in subcortical ischemic vascular disease: a descriptive analysis in CADASIL.

In the elderly, the high prevalence of Alzheimer's disease neuropathology presents a major challenge to the investigation of memory decline in common diseases such as small vessel disease. CADASIL represents a unique clinical model to determine the spectrum of memory impairment in subcortical ischemic vascular dementia (SIVD). One hundred and forty CADASIL patients underwent detailed clinical, neuropsychological and imaging analyses. The Free and Cued Selective Reminding Test was used as a measure of verbal memory. Forty-four out of 140 CADASIL patients (31.4%) presented with memory impairment according to this test. Eight out of 44 (18.2%) subjects with memory impairment matched the definition of the amnestic syndrome of hippocampal type. While alterations in spontaneous recall were related to the severity of subcortical ischemic lesions, the profile of memory impairment, particularly the sensitivity to cueing was found related to other factors such as hippocampal atrophy.

Adoptive T-cell therapy of a lung transplanted patient with severe CMV disease and resistance to antiviral therapy.

Infections with cytomegalovirus (CMV) can induce severe complications after transplantation, particularly in patients resistant to virostatic therapy. Adoptive transfer of CMV-specific T-cell lines has demonstrated promising results in patients after hematopoietic stem cell transplantation. However, the generation of specific T-cell lines ex vivo and their function in vivo is complicated in solid organ transplant (SOT) recipients. Here, we present the successful adoptive transfer of autologous CMV-specific T cells to a lung transplant recipient with ganciclovir-resistant CMV-pneumonia requiring mechanical ventilation. Infused T cells rapidly expanded in vivo and efficiently inhibited viral replication as confirmed by extensive longitudinal immunological monitoring. After full recovery, the patient was released from the clinic. After 4 weeks, the infection reappeared and persisted at a low level even after a second T-cell infusion. Our experimental data indicate that this could be the consequence of the late differentiated phenotype of the infused T cells and therefore their insufficient longevity in vivo. In summary, our report signifies the high therapeutic potential of adoptive immunotherapy in the treatment of SOT recipients when all other measures show no effect. Further studies have to elucidate the most potent strategies to generate antigen-specific T cells with high functional capacity and robust long-term persistence.

The changing landscape of European and international regulation on embryonic stem cell research.

Legislation in individual member states of the European Union on human embryonic stem cell (hESC) research is as divergent as the different cultural, ethical, and religious views on the issue. On the occasion of the public launch of the European Human Embryonic Stem Cell Registry (hESCreg: www.hescreg.eu), a two-day symposium was held on 18 and 19 January 2008 in Berlin to offer participants an overview of state-of-the-art hESC research and legislation throughout Europe and in selected regions of the world. Thirty leading scientists from Europe as well as from the United States, Japan, and Australia reported on a range of aspects related to research on hESC and reviewed the key elements of the newly established hESCreg database of hESC lines. In this article we summarize and complete the information on the current status of international hESC regulation.

Apathy: a major symptom in CADASIL.

OBJECTIVE: The frequency and impact of apathy in subcortical ischemic vascular dementia (SIVD) remain undetermined. The frequency, clinical, neuropsychological, and imaging correlates of apathy were assessed in a large cohort of patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, a genetic model of SIVD. METHODS: Apathy was diagnosed based on Neuropsychiatric Inventory assessment. Degree of disability was assessed by modified Rankin scale, cognitive impairment by Mattis Dementia Rating Scale (MDRS) and Mini-Mental State Examination (MMSE), autonomy by the Instrumental Activities of Daily Living (IADL) scale, and quality of life by SEP-59 self-questionnaire. Validated imaging methods were used to determine the total burden of cerebral lesions. RESULTS: Among 132 patients, 54 (41%) were apathetic. Apathetic patients were older than nonapathetic subjects, had a lower MMSE and MDRS score, had more global disability, and were more limited in IADL. Apathetic patients were more frequently depressed compared to nonapathetic patients and more frequently presented additional neuropsychiatric symptoms. Multiple regression modeling showed a significant and independent association between apathy and a lower score of overall quality of life and between apathy and a higher load of white matter and lacunar lesions. CONCLUSIONS: The results suggest that apathy is common in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), appears in association with cognitive impairment, global functional disability, and severe neuropsychiatric symptoms during the course of the disease, and can occur separately from depression. Apathy has an independent impact on the overall quality of life in CADASIL.

Somatic hypermutations and isotype restricted exceptionally long CDR3H contribute to antibody diversification in cattle.

Antibody diversification in IgM and IgG antibodies was analyzed in an 18-month old bovine (Bos taurus) suffering from naturally occurring chronic and recurrent infections due to bovine leukocyte adhesion deficiency (BLAD). The BLAD, involving impaired leukocyte beta2 integrin expression on leukocytes, develops due to a single point mutation in conserved region of the CD18 gene resulting in substitution of aspartic acid128 with glycine (D128G). Twenty four VDJCmu and 25 VDJCgamma recombinations from randomly constructed cDNA libraries, originating from peripheral blood lymphocytes, were examined for the variable-region structural characteristics in IgM and IgG antibody isotypes. These analyses led to conclude that: (a) expression of exceptionally long CDR3H is isotype restricted to cattle IgM antibody; (b) VDJ recombinations encoding IgM with exceptionally long CDR3H undergo clonal selection and affinity maturation via somatic mutations similar to conventional antibodies; (c) somatic mutations contribute significantly to both IgM and IgG antibody diversification but significant differences exist in the patterns of 'hot spot' in the FR1, FR3 and CDR1H and, also, position-dependant amino acid diversity; and (d) transition nucleotide substitutions predominate over transversions in both VDJCmu and VDJCgamma recombinations consistent with the evolutionary conservation of somatic mutation machinery. Overall, these studies suggest that both somatic mutations and exceptional CDR3H size generation contribute to IgM and IgG antibody diversification in cattle during the development of immune response to naturally occurring chronic and multiple microbial infections.

Development of a European human embryonic stem cell registry.

The number of human embryonic stem cell (hESC) lines that are available and that are subsequently being used in numerous research projects is increasing steadily. However, there is little coordination of hESC line derivation, and comparative information on the characteristics and quality of these cells is sparse. Obtaining consistent information on hESCs is hampered further by legislative fragmentation, particularly in Europe. Recognizing these obstacles, the European Commission has set up a Human Embryonic Stem Cell Registry (hESCreg) to make hESCs and their characterizing information accessible and to ensure that the results of research become more quickly available to the public. The primary objectives of hESCreg are to provide freely accessible information on existing hESC lines, their derivation, molecular characteristics, use and quality. Successful research with listed hESC lines will be used to evaluate clinical potential and thus directly influence policy decisions. The developing integration with other initiatives, such as characterization projects, registries and cell banks, is expected to lead to a common and internationally accepted central reference. The hESCreg provides a first step in this direction and might grow into an internationally funded and administered project.

Development of renin expression in the mouse kidney.

During metanephric kidney development, renin is expressed in the walls of larger intrarenal arteries, but is restricted to the terminal part of the preglomerular arterioles in the adult kidney. Our study describes the three-dimensional development of renin expression in mouse kidneys during fetal and postnatal life. Renin immunoreactivity first appeared at day 14 of development in the cells expressing alpha-smooth muscle actin (alphaSMA) in the arcuate arteries. Before adulthood, the branching of the arcuate arterial tree increased exponentially and renin expression shifted from proximal to distal parts of the tree. Renin expression at branching points or in the cones of growing vessels was not seen. Instead, renin expression appeared after vessel walls and branches were already established, disappeared a few days later, and remained only in the juxtaglomerular regions of afferent arterioles. In these arterioles, coexpression of renin and alphaSMA disappeared gradually, with the terminal cells expressing only renin. At all stages of kidney development, renin expression among comparable vessel segments was heterogeneous. Renin expression remained stable after it reached the terminal parts of afferent arterioles.

COX-2 activity determines the level of renin expression but is dispensable for acute upregulation of renin expression in rat kidneys.

The role of cyclooxygenase 2 (COX-2) in the control of renin is still a matter of debate, since studies with COX-2-deficient mice or with COX-2 inhibitors produced conflicting findings. Therefore, we studied the effect of the COX-2 inhibitor SC-58236 on the regulation of the renin system in adult rat kidneys. Renocortical tissue levels and urinary excretion of PGE(2) were reduced to 65 and 40% of control values, respectively, after a single gavage of SC-58236 and did not further decrease on prolonged treatment. Plasma renin activity (PRA) and renin mRNA levels began to decrease after 3 days and reached a constant level of approximately 60% of control values after 5 days of treatment. Isoproterenol or left renal artery clipping for 2 days increased PRA and renin mRNA to similar levels in both vehicle- and SC-58236-treated rats after 2 days. Pretreatment with SC-58236 for 5 days, however, reduced the absolute increase in PRA and renin mRNA levels. Notably, the relative increases were not different between vehicle- and SC-58236-treated rats. Similar findings were observed for the stimulation of the renin system by angiotensin II inhibition and low salt intake. These findings indicate that COX-2 inhibition attenuates renin secretion and renin gene expression stimulated by a variety of parameters in proportion to the lowering of basal renin activity, while it does not interfere with the different stimulatory mechanism per se. As a consequence, it appears as if COX-2 activity relevantly determines the set point of the activity of the renin system in rat kidneys.

Reporter gene recombination in juxtaglomerular granular and collecting duct cells by human renin promoter-Cre recombinase transgene.

To assess the feasibility of using the renin promoter for expressing Cre recombinase in juxtaglomerular (JG) cells only, we generated five independent transgenic mouse lines (designated hRen-Cre) expressing Cre recombinase under control of a 12.2-kb human renin promoter. In the kidneys of adult mice Cre mRNA (RT-PCR) was found in the renal cortex, with Cre protein (immunohistochemistry) being localized in afferent arterioles and to a lower degree in interlobular arteries. Cre mRNA levels were regulated in a renin-typical fashion by changes in oral salt intake, water restriction, or isoproterenol infusion, indicating the presence of key regulatory elements within 12.2 kb of the 5'-flanking region of the human renin gene. hRen-Cre mice were interbred with both the ROSA26-EGFP and ROSA26-lacZ reporter strains to assess renin promoter activity from Cre-mediated excision of a floxed stop cassette and subsequent enhanced green fluorescent protein (EGFP) and beta-galactosidase (beta-gal) detection. In adult mice, beta-gal staining and EGFP were observed in afferent arterioles and interlobular arteries, overlapping with Cre protein expression. In addition, intense beta-gal staining was found in cortical and medullary collecting ducts where Cre expression was minimal. In embryonic kidneys, beta-gal staining was detected in the developing collecting duct system beginning at embryonic day 12, showing substantial activity of the human renin promoter in the branching ureteric bud. Our data indicate that besides its well-known activity in JG cells and renal vessels the human renin promoter is transiently active in the collecting duct system during kidney development, complicating the use of this approach for JG cell-specific excision of floxed targets.

Cognitive profile in CADASIL.

BACKGROUND: The spectrum of cognitive alterations associated with CADASIL, a model of pure vascular dementia, has not been thoroughly evaluated. OBJECTIVES: The aims of this study were: (i) to describe the cognitive profile in CADASIL patients according to age; (ii) to compare the profile of patients with dementia with that of patients without dementia; and (iii) to determine the association between alterations in performance in different cognitive domains. METHODS: Forty two consecutive individuals with CADASIL (35-73 years old) were investigated. Cognitive skills were analysed in five domains (executive functions, reasoning, attention, memory, visuospatial abilities) according to age and compared between patients with and without dementia. Associations between cognitive performance and stroke were tested. RESULTS: The youngest patients presented with attention (69%), memory (70%), and executive disturbances (100%). Visuospatial abilities and reasoning deteriorated with age, mainly after the age of 60. About one quarter of patients had dementia, and 75% of these were >60 years of age. Age >60 years was associated with a Rankin score >3 and a significant deficit in all cognitive domains. No association was found between dementia and the number of ischaemic attacks. Episodic memory disorder was characterised by difficulties in retrieval rather than impairment of the encoding process. CONCLUSION: Cognitive decline in CADASIL is dominated by early impairment of executive functions. Skills in other cognitive domains deteriorate with age and are found to be diffusely impaired in patients with dementia. The relative preservation of the encoding process in episodic memory impairment, even in individuals with dementia, is noteworthy.

Regulation of erythropoietin production.

The glycoprotein hormone erythropoietin (EPO) is an essential growth and survival factor for erythroid progenitor cells, and the rate of red blood cell production is normally determined by the serum EPO concentration. EPO production is inversely related to oxygen availability, so that an effective feedback loop is established, which controls erythropoiesis. Since recombinant EPO became available as an effective therapeutic agent, significant progress has also been made in understanding the basis of this feedback control. The main determinant of EPO synthesis is the transcriptional activity of its gene in liver and kidneys, which is related to local oxygen tensions. This control is achieved by hypoxia-inducible transcription factors (HIF), consisting of a constitutive beta-subunit and one of two alternative oxygen-regulated HIFalpha subunits (HIF-1alpha and HIF-2alpha). In the presence of oxygen (normoxia) the HIFalpha subunits are hydroxylated, which targets them for proteasomal degradation. Under hypoxia, because of the lack of molecular oxygen, HIF cannot be hydroxylated and is thereby stabilized. Although HIF-1alpha was the first transcription factor identified through its ability to bind to an enhancer sequence of the EPO gene, more recent evidence suggests that HIF-2alpha is responsible for the regulation of EPO. Although EPO is a prime example for an oxygen- regulated gene, the role of the HIF system goes far beyond the regulation of EPO, because it operates widely in almost all cells and controls a broad transcriptional response to hypoxia, including genes involved in cell metabolism, angiogenesis and vascular tone. Further evidence suggests that apart from its effect as an erythropoietic hormone EPO acts as a paracrine, tissue-protective protein in the brain and possibly also in other organs.