Novel low shear 3D bioreactor for high purity mesenchymal stem cell production.

Bone marrow derived human Mesenchymal Stem Cells (hMSCs) are an attractive candidate for regenerative medicine. However, their harvest can be invasive, painful, and expensive, making it difficult to supply the enormous amount of pure hMSCs needed for future allogeneic therapies. Because of this, a robust method of scaled bioreactor culture must be designed to supply the need for high purity, high density hMSC yields. Here we test a scaled down model of a novel bioreactor consisting of an unsubmerged 3D printed Polylactic Acid (PLA) lattice matrix wetted by culture media. The growth matrix is uniform, replicable, and biocompatible, enabling homogenous cell culture in three dimensions. The goal of this study was to prove that hMSCs would culture well in this novel bioreactor design. The system tested resulted in comparable stem cell yields to other cell culture systems using bone marrow derived hMSCs, while maintaining viability (96.54% ±2.82), high purity (>98% expression of combined positive markers), and differentiation potential.

Exercise training prevents obesity-associated disorders: Role of miRNA-208a and MED13.

Exercise training (ET) has been established as an important treatment for obesity, since it counteracts aberrant cardiac metabolism and weight gain; however, underlying mechanisms remain to be further determined. MicroRNAs (miRNAs) inhibit protein expression by base-pairing with the 3' UTRs of mRNA targets. MiRNA-208a is a cardiac-specific miRNA that regulates ß-MHC content and systemic energy homeostasis via MED13. We investigated whether ET regulates the cardiac miRNA-208a and its target MED13, reducing the weight gain and ß-MHC expression in obese Zucker rats (OZR). OZR (n = 11) and Lean (L, n = 10) male rats were assigned into 4 groups: OZR, trained OZR (OZRT), L and trained L (LT). Swimming ET consisted of 60 min of duration, 1x/day, 5x/week/10 weeks. MiRNA and gene expression were analyzed by real-time PCR and protein levels by western blot. Resting bradycardia was observed in trained groups. ET reduced weight gain, retroperitoneal fat weight and adipocyte cell size in OZRT compared with OZR group. Cardiac miRNA-208a levels increased 57% in OZR paralleled with a decrease of 39% in MED13 protein levels compared with L group. In contrast, ET corrected the cardiac miRNA-208a and MED13 levels in OZRT compared with L group. Furthermore, ET reduced the increased cardiac mass and normalized ß-MHC protein levels caused by obesity. These results suggest that ET can prevent weight gain and pathological cardiac hypertrophy via increased of cardiac MED13 by the regulation of miRNA-208a. Therefore, miRNA-208a can be used as potential therapeutic target for metabolic and cardiac disorders.

Antisense Therapy for Cardiovascular Diseases.

Antisense oligonucleotide therapy is a growing field in cardiac, metabolic, and muscular diseases. This precision therapy allows for treatment of diseases due to specific genetic defects. Antisense has few side effects and is relatively long lasting. Some major targets for antisense therapy include hyperglycemia, hyperlipidemia, and hypercholesterolemia. ISIS Pharmaceuticals recently commercialized antisense therapy with Kynamro (Mipomersen) for homozygous familial hypercholesterolemia, opening the door for other antisense oligonucleotides for lowering proteins. Antisense can also be used to increase proteins that are inhibited by mutant exons. Sarepta is testing exon 51 skipping in the mutated dystrophin gene, which if successful will help affected individuals walk, and may help restore some cardiac function. These antisense techniques also could be applied as antisense therapies to overcome gene defects in hypertension, heart disease, muscular defects and metabolic syndrome.

Aerobic exercise training promotes physiological cardiac remodeling involving a set of microRNAs.

Left ventricular (LV) hypertrophy is an important physiological compensatory mechanism in response to chronic increase in hemodynamic overload. There are two different forms of LV hypertrophy, one physiological and another pathological. Aerobic exercise induces beneficial physiological LV remodeling. The molecular/cellular mechanisms for this effect are not totally known, and here we review various mechanisms including the role of microRNA (miRNA). Studies in the heart, have identified antihypertrophic miRNA-1, -133, -26, -9, -98, -29, -378, and -145 and prohypertrophic miRNA-143, -103, -130a, -146a, -21, -210, -221, -222, -27a/b, -199a/b, -208, -195, -499, -34a/b/c, -497, -23a, and -15a/b. Four miRNAs are recognized as cardiac-specific: miRNA-1, -133a/b, -208a/b, and -499 and called myomiRs. In our studies we have shown that miRNAs respond to swimming aerobic exercise by 1) decreasing cardiac fibrosis through miRNA-29 increasing and inhibiting collagen, 2) increasing angiogenesis through miRNA-126 by inhibiting negative regulators of the VEGF pathway, and 3) modulating the renin-angiotensin system through the miRNAs-27a/b and -143. Exercise training also increases cardiomyocyte growth and survival by swimming-regulated miRNA-1, -21, -27a/b, -29a/c, -30e, -99b, -100, -124, -126, -133a/b, -143, -144, -145, -208a, and -222 and running-regulated miRNA-1, -26, -27a, -133, -143, -150, and -222, which influence genes associated with the heart remodeling and angiogenesis. We conclude that there is a potential role of these miRNAs in promoting cardioprotective effects on physiological growth.

Infrared fluorescent protein 1.4 genetic labeling tracks engrafted cardiac progenitor cells in mouse ischemic hearts.

Stem cell therapy has a potential for regenerating damaged myocardium. However, a key obstacle to cell therapy's success is the loss of engrafted cells due to apoptosis or necrosis in the ischemic myocardium. While many strategies have been developed to improve engrafted cell survival, tools to evaluate cell efficacy within the body are limited. Traditional genetic labeling tools, such as GFP-like fluorescent proteins (eGFP, DsRed, mCherry), have limited penetration depths in vivo due to tissue scattering and absorption. To circumvent these limitations, a near-infrared fluorescent mutant of the DrBphP bacteriophytochrome from Deinococcus radiodurans, IFP1.4, was developed for in vivo imaging, but it has yet to be used for in vivo stem/progenitor cell tracking. In this study, we incorporated IFP1.4 into mouse cardiac progenitor cells (CPCs) by a lentiviral vector. Live IFP1.4-labeled CPCs were imaged by their near-infrared fluorescence (NIRF) using an Odyssey scanner following overnight incubation with biliverdin. A significant linear correlation was observed between the amount of cells and NIRF signal intensity in in vitro studies. Lentiviral mediated IFP1.4 gene labeling is stable, and does not impact the apoptosis and cardiac differentiation of CPC. To assess efficacy of our model for engrafted cells in vivo, IFP1.4-labeled CPCs were intramyocardially injected into infarcted hearts. NIRF signals were collected at 1-day, 7-days, and 14-days post-injection using the Kodak in vivo multispectral imaging system. Strong NIRF signals from engrafted cells were imaged 1 day after injection. At 1 week after injection, 70% of the NIRF signal was lost when compared to the intensity of the day 1 signal. The data collected 2 weeks following transplantation showed an 88% decrease when compared to day 1. Our studies have shown that IFP1.4 gene labeling can be used to track the viability of transplanted cells in vivo.

Genetically reprogrammed, liver-derived insulin-producing cells are glucose-responsive, but susceptible to autoimmune destruction in settings of murine model of type 1 diabetes.

Many previous studies demonstrate that hepatocytes can be reprogrammed into insulin-producing cells (IPCs) utilizing viral vector-mediated delivery of pancreatic transcription factors (PTFs). However, whether these liver-derived IPCs are susceptible to autoimmune attack in animal models of type 1 diabetes remains unclear, in part due to the immunogenicity of the viral vectors used to introduce PTF genes. Adeno-associated virus serotype 2 vector-expressing Pdx1-VP16 (Pdx1) and Ngn3 were prepared and injected into the portal vein of streptozotocin (Stz)/diabetic NOD/SCID mice. The presence of glucose-responsive liver-IPCs and their susceptibility to anti-beta cell autoimmunity were assessed by blood glucose levels, insulin content, IPC cell distribution, and intraperitoneal glucose tolerance test following subtotal pancreatectomy (Px) and passive transfer of diabetogenic splenocytes isolated from diabetic female NOD mice. A combination of two PTF genes (Pdx1/Ngn3) effectively reprogrammed liver cells into glucose-responsive IPCs. These IPCs corrected hyperglycemia in Stz/diabetic NOD/SCID mice and maintained normoglycemia following subtotal Px, indicating that liver-derived IPCs could maintain glucose homeostasis. Importantly, we also demonstrated that the glucose-responsive liver-derived IPCs were susceptible to autoimmune destruction by diabetogenic splenocytes, as indicated by progressive elevation in blood glucose levels as well as mixed T-, and B-lymphocytic infiltrates surrounding liver-IPCs 2~3 weeks following transferring of diabetogenic splenocytes into NOD/SCID mice, and confirmed by immunohistochemical studies. In conclusion, genetically reprogrammed liver-IPCs, like pancreatic islet beta-cells, are susceptible to autoimmune attack, suggesting that for cell-replacement therapy of treating type 1 diabetes, beta-cell surrogates may require concomitant immunotherapy to avoid autoimmune destruction.

Genetic modification of stem cells for cardiac, diabetic, and hemophilia transplantation therapies.

Gene modification of stem cells prior to their transplantation enhances their survival and increases their function in cell therapy. Like the famous Trojan horse, the gene-modified cell has to gain entrance into the host's walls and survive to deliver its transgene products. Using cellular, molecular, and gene manipulation techniques, the transplanted cell can be protected in a hostile environment from immune rejection, inflammation, hypoxia, and apoptosis. Genetic engineering to modify cells involves construction of functional gene sequences and their insertion into stem cells. The modifications can be simple reporter genes or complex cassettes with gene switches, cell-specific promoters, and multiple transgenes. We discuss methods to deliver and construct gene cassettes with viral and nonviral delivery, siRNA, and conditional Cre/Lox P. We review the current uses of gene-modified stem cells in cardiovascular disease, diabetes, and hemophilia.

Gene, stem cell, and future therapies for orphan diseases.

There are an estimated 7,000 "orphan diseases," but treatments are currently available for only about 5% of them. Recent progress in the advanced platforms of gene therapy, stem cell therapy, gene modification, and gene correction offers possibilities for new therapies and cures for rare diseases. Many rare diseases are genetic in origin, and gene therapy is being successfully applied to treat them. Human stem cell therapy, apart from bone marrow transplants, is still experimental. Genetic modification of stem cells can make stem cell-based products more effective. Autologous induced pluripotent stem (iPS) cells, when combined with new classes of artificial nucleases, have great potential in the ex vivo repair of specific mutated DNA sequences (zinc-finger proteins and transactivator-like effector nucleases). Patient-specific iPS cells can be corrected and transplanted back into the patient. Stem cells secrete paracrine factors that could become new therapeutic tools in the treatment of orphan diseases. Gene therapy and stem cell therapy with DNA repair are promising approaches to the treatment of rare, intractable diseases.

What the Orphan Drug Act has done lately for children with rare diseases: a 10-year analysis.

OBJECTIVES: The 1983 US Orphan Drug Act (ODA) provided incentives to stimulate treatment product development for patients with rare disease. This article highlights a decade of ODA contributions to this goal for children with RDs. METHODS: An internal US Food and Drug Administration database was the information source for orphan designations, marketing approvals, and prevalence numbers for 2000 to 2009. Product categorization was based on the disease age of onset for which they received designation. Category 1 products were for diseases with onset exclusively in Childhood; Category 2 products were for diseases with onset at any age; and Category 3 products were for diseases with adult onset only. Disease prevalence distributions were analyzed by using population intervals of 20 000. RESULTS: From 2000 to 2009, 1138 orphan drugs were designated and 148 received marketing approval, of which 38 (26%) were for pediatric diseases. The proportion of approvals for pediatric products increased from 17.5% (10 of 57) in the first half of the decade, to 30.8% (28 of 91) in the second. More products received designation and marketing approval for pediatric diseases with prevalence numbers fewer than 20 000 than for any other prevalence subgroup. The median disease prevalence for all pediatric orphan designations that received marketing approval was 8972. Among the pediatric orphan drug approvals categorized by therapeutic class, the endocrine/metabolic drugs had the largest representation (39%). CONCLUSIONS: The ODA incentives have led to increased product availability for RDs overall, with an increasing number of marketing approvals for children this past decade.

Swimming training in rats increases cardiac MicroRNA-126 expression and angiogenesis.

PURPOSE: MicroRNA (miRNA)-126 is angiogenic and has two validated targets: Sprouty-related protein 1 (Spred-1) and phosphoinositol-3 kinase regulatory subunit 2 (PI3KR2), negative regulators of angiogenesis by VEGF pathway inhibition. We investigated the role of swimming training on cardiac miRNA-126 expression related to angiogenesis. METHODS: Female Wistar rats were assigned to three groups: sedentary (S), training 1 (T1, moderate volume), and training 2 (T2, high volume). T1 consisted of 60 min·d of swimming, five times per week for 10 wk with 5% body overload. T2 consisted of the same protocol of T1 until the eighth week; in the ninth week, rats trained for two times a day, and in the 10th week, rats trained for three times a day. MiRNA and PI3KR2 gene expression analysis was performed by real-time polymerase chain reaction in heart muscle. We assessed markers of training, the cardiac capillary-fiber ratio, cardiac protein expression of VEGF, Spred-1, Raf-1/ERK 1/2, and PI3K/Akt/eNOS. RESULTS: The cardiac capillary-fiber ratio increased in T1 (58%) and T2 (101%) compared with S. VEGF protein expression was increased 42% in T1 and 108% in T2. Cardiac miRNA-126 expression increased 26% (T1) and 42% (T2) compared with S, correlated with angiogenesis. The miRNA-126 target Spred-1 protein level decreased 41% (T1) and 39% (T2), which consequently favored an increase in angiogenic signaling pathway Raf-1/ERK 1/2. On the other hand, the gene expression of PI3KR2, the other miRNA-126 target, was reduced 39% (T1) and 78% (T2), and there was an increase in protein expression of components of the PI3K/Akt/eNOS signaling pathway in the trained groups. CONCLUSIONS: This study showed that aerobic training promotes an increase in the expression of miRNA-126 and that this may be related to exercise-induced cardiac angiogenesis, by indirect regulation of the VEGF pathway and direct regulation of its targets that converged in an increase in angiogenic pathways, such as MAPK and PI3K/Akt/eNOS.

Exercise training prevents the microvascular rarefaction in hypertension balancing angiogenic and apoptotic factors: role of microRNAs-16, -21, and -126.

Aerobic exercise training (ET) lowers hypertension and improves patient outcomes in cardiovascular disease. The mechanisms of these effects are largely unknown. We hypothesized that ET modulates microRNAs (miRNAs) involved in vascularization. miRNA-16 regulates the expression of vascular endothelial growth factor and antiapoptotic protein Bcl-2. miRNA-21 targets Bcl-2. miRNA-126 functions by repressing regulators of the vascular endothelial growth factor pathway. We investigated whether miRNA-16, -21 and -126 are modulated in hypertension and by ET. Twelve-week-old male spontaneously hypertensive rats (SHRs; n=14) and Wistar Kyoto (WKY; n=14) rats were assigned to 4 groups: SHRs, trained SHRs (SHR-T), Wistar Kyoto rats, and trained Wistar Kyoto rats. ET consisted of 10 weeks of swimming. ET reduced blood pressure and heart rate in SHR-Ts. ET repaired the slow-to-fast fiber type transition in soleus muscle and the capillary rarefaction in SHR-Ts. Soleus miRNA-16 and -21 levels increased in SHRs paralleled with a decrease of 48% and 25% in vascular endothelial growth factor and Bcl-2 protein levels, respectively. Hypertension increased Bad and decreased Bcl-x and endothelial NO synthase levels and lowered p-Bad(ser112):Bad ratio. ET in SHR-Ts reduced miRNA-16 and -21 levels and elevated vascular endothelial growth factor and Bcl-2 levels. ET restored soleus endothelial NO synthase levels plus proapoptotic and antiapoptotic mediators in SHR-Ts, indicating that the balance between angiogenic and apoptotic factors may prevent microvascular abnormalities in hypertension. miRNA-126 levels were reduced in SHRs with an increase of 51% in phosphoinositol-3 kinase regulatory subunit 2 expression but normalized in SHR-Ts. Our data show that ET promoted peripheral revascularization in hypertension, which could be associated with regulation of select miRNAs, suggesting a mechanism for its potential therapeutic application in vascular diseases.

LOX-1 and angiotensin receptors, and their interplay.

The renin-angiotensin system (RAS) plays an important role in regulating blood pressure, water-salt balance and the pathogenesis of cardiovascular diseases. Angiotensin II (Ang II) is the physiologically active mediator and mediates the main pathophysiological actions in RAS. Ang II exerts the effects by activating its receptors, primarily type 1 (AT1R) and type 2 (AT2R). Most of the known pathophysiological effects of Ang II are mediated by AT1R activation. The precise physiological function of AT2R is still not clear. Generally, AT2R is considered to oppose the effects of AT1R. Lectin-like oxidized low-density lipoprotein scavenger receptor-1 (LOX-1) is one of the major receptors responsible for binding, internalizing and degrading ox-LDL. The activation of LOX-1 has been known to be related to many pathophysiological events, including endothelial dysfunction and injury, fibroblast growth, and vascular smooth muscle cell hypertrophy. Many of these alterations are present in atherosclerosis, hypertension, and myocardial ischemia and remodeling. A growing body of evidence suggests the existence of a cross-talk between LOX-1 and Ang II receptors. Their interplays are embodied in the reciprocal regulation of their expression and activity. Their interplays are involved in a series of signals. Recent studies suggests that reactive oxygen species (ROS), nitric oxide (NO), protein kinase C (PKC) and mitogen activated protein kinases (MAPKs) are important signals responsible for their cross-talk. This paper reviews these aspects of dyslipidemia and RAS activation.

Aerobic exercise training-induced left ventricular hypertrophy involves regulatory MicroRNAs, decreased angiotensin-converting enzyme-angiotensin ii, and synergistic regulation of angiotensin-converting enzyme 2-angiotensin (1-7).

Aerobic exercise training leads to a physiological, nonpathological left ventricular hypertrophy; however, the underlying biochemical and molecular mechanisms of physiological left ventricular hypertrophy are unknown. The role of microRNAs regulating the classic and the novel cardiac renin-angiotensin (Ang) system was studied in trained rats assigned to 3 groups: (1) sedentary; (2) swimming trained with protocol 1 (T1, moderate-volume training); and (3) protocol 2 (T2, high-volume training). Cardiac Ang I levels, Ang-converting enzyme (ACE) activity, and protein expression, as well as Ang II levels, were lower in T1 and T2; however, Ang II type 1 receptor mRNA levels (69% in T1 and 99% in T2) and protein expression (240% in T1 and 300% in T2) increased after training. Ang II type 2 receptor mRNA levels (220%) and protein expression (332%) were shown to be increased in T2. In addition, T1 and T2 were shown to increase ACE2 activity and protein expression and Ang (1-7) levels in the heart. Exercise increased microRNA-27a and 27b, targeting ACE and decreasing microRNA-143 targeting ACE2 in the heart. Left ventricular hypertrophy induced by aerobic training involves microRNA regulation and an increase in cardiac Ang II type 1 receptor without the participation of Ang II. Parallel to this, an increase in ACE2, Ang (1-7), and Ang II type 2 receptor in the heart by exercise suggests that this nonclassic cardiac renin-angiotensin system counteracts the classic cardiac renin-angiotensin system. These findings are consistent with a model in which exercise may induce left ventricular hypertrophy, at least in part, altering the expression of specific microRNAs targeting renin-angiotensin system genes. Together these effects might provide the additional aerobic capacity required by the exercised heart.

Therapies for inborn errors of metabolism: what has the orphan drug act delivered?

OBJECTIVE: The 1983 US Orphan Drug Act established a process through which promising therapies are designated as orphan products and, later, with satisfactory safety and efficacy data, receive marketing approval and fiscal incentives. We examined accomplishments in drug development for inborn errors of metabolism (IEMs). METHODS: Food and Drug Administration data were used to identify orphan product designations and approvals for IEMs, and the trends for the past 26 years were summarized. Individual clinical development times (CDTs) from filing investigational new drug application to marketing approval were determined. RESULTS: We examined 1956 orphan product designations from 1983 through 2008 and found 93 (4.8%) for IEMs. Of those, 24 (25.8%) received marketing approval. This proportion of approval was significantly (P = .036) higher than that for non-IEM orphan products (17%). Among the IEM products, disorders of complex molecules received the most designations and approvals (61 and 11, respectively). Among the subgroups, lysosomal storage diseases received the most designations and approvals (43 and 9, respectively), whereas mitochondrial diseases (other than fatty acid oxidation disorders) received 7 designations with no approvals. We then examined the CDTs for the approved IEM products and found a median of 6.4 years (range: 2.6-25.1 years). Biological products had significantly shorter CDTs than drugs (mean: 4.6 vs 11.0 years; P = .003). CONCLUSION: For 26 years, the Orphan Drug Act has generated new therapies for IEMs. Why some IEMs have motivated successful drug development and others have not remains enigmatic; yet the needs of IEM patients without treatment are a certainty.

Growth differentiation factor 15 and coronary collateral formation.

BACKGROUND: The coronary collateral circulation can reduce sudden cardiac death,myocardial cell loss,and infarct size.Growth differentiation factor 15(GDF-15),a member of the transforming growth factor-beta (TGF-beta) superfamily,has been reported to have a prognostic predicting value in coronary artery disease. HYPOTHESIS: GDF-15 can be related with the extent of collateral formation. OBJECTIVE: Growth differentiation factor 15 (GDF-15), a member of the transforming growth factor-beta (TGF-beta) superfamily, has been reported to have a prognostic predicting value in coronary artery disease. We sought to investigate whether GDF-15 is related to coronary collateral development in patients with coronary heart disease. METHODS: A cross-sectional study was performed in 201 patients, who were admitted for selective coronary angiography. Patients were divided into 3 groups based on Rentrop's classification of coronary collaterals. Group 1: patients with coronary collateral presence, which was defined by Rentrop's grade 1-3 collateral development. Group 2: patients with grade 0 collateral development. Group 3: control group were patients with a normal coronary angiogram. The levels of plasma GDF-15, asymmetric dimethylarginine (ADMA), and soluble Fms-related tyrosine kinase-1 (sFLT-1) were compared among the 3 groups. RESULTS: There were significant statistical differences in plasma sFLT-1, ADMA, and GDF-15 concentrations among the different collateral groups. The correlations between Rentrop's grade and the cytokines were significant. A positive correlation was found between Rentrop's grade and GDF-15 (r = 0.187, P < 0.05). The correlations between the levels of plasma sFLT-1, ADMA, and Rentrop's grade were significant, with the correlation coefficient of r = 0.181, P < 0.05 (sFLT-1) and r = - 0.646, P < 0.001 (ADMA), respectively. CONCLUSIONS: Our findings suggest that GDF-15 levels increase with the extent of collateral formation. In that case, the patients with a higher level of GDF-15 may predict more severe coronary stenosis, which has a higher probability to develop collaterals.

Hypoxic preconditioning enhances the benefit of cardiac progenitor cell therapy for treatment of myocardial infarction by inducing CXCR4 expression.

Myocardial infarction rapidly depletes the endogenous cardiac progenitor cell pool, and the inefficient recruitment of exogenously administered progenitor cells limits the effectiveness of cardiac cell therapy. Recent reports indicate that interactions between the CXC chemokine stromal cell-derived factor 1 and its receptor CXC chemokine receptor 4 (CXCR4) critically mediate the ischemia-induced recruitment of bone marrow-derived circulating stem/progenitor cells, but the expression of CXCR4 in cardiac progenitor cells is very low. Here, we studied the influence of hypoxia on CXCR4 expression in cardiac progenitor cells, on the recruitment of intravenously administered cells to ischemic heart tissue, and on the preservation of heart function in a murine myocardial infarction model. We found that hypoxic preconditioning increased CXCR4 expression in CLK (cardiosphere-derived, Lin(-)c-kit(+) progenitor) cells and markedly augmented CLK cell migration (in vitro) and recruitment (in vivo) to the ischemic myocardium. Four weeks after surgically induced myocardial infarction, infarct size and heart function were significantly better in mice administered hypoxia-preconditioned CLK cells than in mice treated with cells cultured under normoxic conditions. Furthermore, these effects were largely abolished by the addition of a CXCR4 inhibitor, indicating that the benefits of hypoxic preconditioning are mediated by the stromal cell-derived factor 1/CXCR4 axis, and that therapies targeting this axis may enhance cardiac-progenitor cell-based regenerative therapy.

Brain renin angiotensin in disease.

A brain renin angiotensin system (RAS) and its role in cardiovascular control and fluid homeostasis was at first controversial. This was because a circulating kidney-derived renin angiotensin system was so similar and well established. But, the pursuit of brain RAS has proven to be correct. In the course of accepting brain RAS, high standards of proof attracted state of the art techniques in all the new developments of biology. Consequently, brain RAS is a robust concept that has enlightened neuroscience as well as cardiovascular physiology and is a model neuropeptide system. Molecular biology confirmed the components of brain RAS and their location in the brain. Transgenic mice and rats bearing renin and extra copies of angiotensinogen genes revealed the importance of brain RAS. Cre-lox delivery in vectors has enabled pinpoint gene deletion of brain RAS in discrete brain nuclei. The new concept of brain RAS includes ACE-2, Ang1-7, and prorenin and Mas receptors. Angiotensin II (ANG II) generated in the brain by brain renin has many neural effects. It activates behavioral effects by selective activation of ANG II receptor subtypes in different locations. It regulates sympathetic activity and baroreflexes and contributes to neurogenic hypertension. New findings implicate brain RAS in a much wider range of neural effects. We review brain RAS involvement in Alzheimer's disease, stroke memory, and learning alcoholism stress depression. There is growing evidence to consider developing treatment strategies for a variety of neurological disease states based on brain RAS.

Stem cell therapy for heart failure: the science and current progress.

Cell therapy, particularly with stem cells, has created great interest as a solution to the fact that there are limited treatments for postischemic heart disease and none that can regenerate damaged heart cells to strengthen cardiac performance. From the first efforts with myoblasts to recent clinical trials with bone marrow-derived stem cells, early reports of cell therapy suggest improvement in cardiac performance as well as other clinical end points. Based on these exciting but tentative results, other stem cell types are being explored for their particular advantages as a source of adult stem cells. Autologous adipose-derived stem cells are multilinear and can be obtained relatively easily in large quantities from patients; cardiac-derived stem cells are highly appropriate for engraftment in their natural niche, the heart. Human umbilical cord blood cells are potentially forever young and allogenic adult mesenchymal stem cells appear not to evoke the graft versus host reaction. Human embryonic stem cells are effective and can be scaled up for supply purposes. The recent discovery of induced pluripotentcy in human adult stem cells, with only three transcription factor genes, opens a whole new approach to making autologous human pluripotent stem cells from skin or other available tissues. Despite the excitement, stem cells may have to be genetically modified with heme oxygenase, Akt or other genes to survive transplantation in a hypoxic environment. Homing factors and hormones secreted from transplanted stem cells may be more important than cells if they provide the necessary stimulus to trigger cardiac regrowth to replace scar tissue. As we await results from larger and more prolonged clinical trials, the science of stem cell therapy in cardiac disease keeps progressing.