Oxidation Reduction Potential (ORP) is Predictive of Complications Following Pediatric Cardiac Surgery.

Oxidation reduction potential (ORP) or Redox is the ratio of activity between oxidizers and reducers. Oxidative stress (OS) can cause cellular injury and death, and is important in the regulation of immune response to injury or disease. In the present study, we investigated changes in the redox system as a function of cardiopulmonary bypass (CPB) in pediatric patients. 664 plasma samples were collected from 162 pediatric patients having cardiac surgery of various CPB times. Lower ORP values at 12 h post-CPB were associated with poor survival rate (mean ± SD 167 ± 20 vs. 138 ± 19, p = 0.005) and higher rate of thrombotic complications (153 ± 21 vs. 168 ± 20, p < 0.008). Similarly, patients who developed infections had lower ORP values at 6 h (149 ± 19 vs. 160 ± 22, p = 0.02) and 12 h (156 ± 17 vs. 168 ± 21, p = 0.004) post-CPB. Patients that developed any post-operative complication also had lower 6 h (149 ± 17 vs. 161 ± 23, p = 0.002) and 12 h (157 ± 18 vs. 170 ± 21, p = 0.0007) post-CPB ORP values. Free hemoglobin and IL-6, IL-10, and CRP were not associated with ORP levels. However, higher haptoglobin levels preoperatively were protective against decreases in ORP. Decreased ORP is a marker for poor outcome and predictive of post-operative thrombosis, infection, and other complications in critically ill pediatric cardiac surgery patients. These results suggest that redox imbalance and OS may contribute to the risk of complications and poor outcome in pediatric CBP patients. Haptoglobin may be a marker for increased resilience to OS in this population.

Comparison of fetal mesencephalic grafts, AAV-delivered GDNF, and both combined in an MPTP-induced nonhuman primate Parkinson's model.

We combined viral vector delivery of human glial-derived neurotrophic factor (GDNF) with the grafting of dopamine (DA) precursor cells from fetal ventral mesencephalon (VM) to determine whether these strategies would improve the anti-Parkinson's effects in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys, an animal model for Parkinson's disease (PD). Both strategies have been reported as individually beneficial in animal models of PD, leading to clinical studies. GDNF delivery has also been reported to augment VM tissue implants, but no combined studies have been done in monkeys. Monkeys were treated with MPTP and placed into four balanced treatment groups receiving only recombinant adeno-associated virus serotype 5 (rAAV5)/hu-GDNF, only fetal DA precursor cells, both together, or a buffered saline solution (control). The combination of fetal precursors with rAAV5/hu-GDNF showed significantly higher striatal DA concentrations compared with the other treatments, but did not lead to greater functional improvement in this study. For the first time under identical conditions in primates, we show that all three treatments lead to improvement compared with control animals.

Effects of neonatal neural progenitor cell implantation on adult neuroanatomy and cognition in the Ts65Dn model of Down syndrome.

As much of the aberrant neural development in Down syndrome (DS) occurs postnatally, an early opportunity exists to intervene and influence life-long cognitive development. Recent success using neural progenitor cells (NPC) in models of adult neurodegeneration indicate such therapy may be a viable option in diseases such as DS. Murine NPC (mNPC, C17.2 cell line) or saline were implanted bilaterally into the dorsal hippocampus of postnatal day 2 (PND 2) Ts65Dn pups to explore the feasibility of early postnatal treatment in this mouse model of DS. Disomic littermates provided karyotype controls for trisomic pups. Pups were monitored for developmental milestone achievement, and then underwent adult behavior testing at 14 weeks of age. We found that implanted mNPC survived into adulthood and migrated beyond the implant site in both karyotypes. The implantation of mNPC resulted in a significant increase in the density of dentate granule cells. However, mNPC implantation did not elicit cognitive changes in trisomic mice either neonatally or in adulthood. To the best of our knowledge, these results constitute the first assessment of mNPC as an early intervention on cognitive ability in a DS model.

Cellular repair in the parkinsonian nonhuman primate brain.

Parkinson disease (PD) is a neurodegenerative disorder that provides a useful model for testing cell replacement strategies to rejuvenate the affected dopaminergic neural systems, which have been destroyed by aging and the disease. We first showed that grafts of fetal dopaminergic neurons can reverse parkinsonian motor deficits induced by the toxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), validating the feasibility of cellular repair in a primate nervous system. Subsequent clinical trials in Parkinson patients showed encouraging results, including long-term improvement of neurological signs and reduction of medications in some patients. However, many experienced little therapeutic benefit, and some recipients experienced dyskinesias, suggesting a lack of regulated control of the grafts. We have since attempted to improve cell replacements by placing grafts in their correct anatomical location in the substantia nigra and using strategies such as co-grafting fetal striatal tissue or growth factors into the physiologic striatal targets. Moreover, the use of fetal cells depends on a variable supply of donor material, making it difficult to standardize cell quality and quantity. Therefore, we have also explored possibilities of using human neural stem cells (hNSCs) to ameliorate parkinsonism in nonhuman primates with encouraging results. hNSCs implanted into the striatum showed a remarkable migratory ability and were found in the substantia nigra, where a small number appeared to differentiate into dopamine neurons. The majority became growth factor-producing glia that could provide beneficial effects on host dopamine neurons. Studies to determine the optimum stage of differentiation from embryonic stem cells and to derive useful cells from somatic cell sources are in progress.

Impact of degradable macromer content in a poly(ethylene glycol) hydrogel on neural cell metabolic activity, redox state, proliferation, and differentiation.

Hydrogels that degrade at different rates were prepared by copolymerizing slowly degrading macromer poly(ethylene glycol) (PEG) dimethacrylate with a faster degrading macromer poly(lactic acid)-b-PEG-b-poly(lactic acid) dimethacrylate. A clinically relevant population of neural cells composed of differentiated neurons and multipotent precursor cells was cultured within hydrogels. Within 2 h after encapsulation, metabolic activity was higher in hydrogels prepared with increasing levels of degradable content. This improvement was accompanied by a reduction in intracellular redox state and an increase in the fraction of glutathione in the reduced state, both of which persisted throughout 7 days of culture and which may be the result of radical scavenging by lactic acid. Importantly, an increase in cellular proliferation was observed in gels prepared with increasing degradable macromer content after 7 days of growth without a shift in the cellular composition of the culture toward the glial cell phenotype. The findings of this study provide additional insight into the growth of neural cells in PEG-based hydrogels. Results suggest that lactic acid released during gel degradation may impact the function of encapsulated cells, a finding of general interest to biomaterials scientists who focus on the development of degradable polymers for cell culture and drug delivery devices.

Human neural stem cells migrate along the nigrostriatal pathway in a primate model of Parkinson's disease.

Although evidence of damage-directed neural stem cell (NSC) migration has been well-documented in the rodent, to our knowledge it has never been confirmed or quantified using human NSC (hNSC) in an adult non-human primate modeling a human neurodegenerative disease state. In this report, we attempt to provide that confirmation, potentially advancing basic stem cell concepts toward clinical relevance. hNSCs were implanted into the caudate nucleus (bilaterally) and substantia nigra (unilaterally) of 7, adult St. Kitts African green monkeys (Chlorocebus sabaeus) with previous exposure to systemic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a neurotoxin that disrupts the dopaminergic nigrostriatal pathway. A detailed quantitative analysis of hNSC migration patterns at two time points (4 and 7 months) following transplantation was performed. Density contour mapping of hNSCs along the dorsal-ventral and medial-lateral axes of the brain suggested that >80% of hNSCs migrated from the point of implantation to and along the impaired nigrostriatal pathway. Although 2/3 of hNSCs were transplanted within the caudate, <1% of 3x10(6) total injected donor cells were identified at this site. The migrating hNSC did not appear to be pursuing a neuronal lineage. In the striatum and nigrostriatal pathway, but not in the substantia nigra, some hNSCs were found to have taken a glial lineage. The property of neural stem cells to align themselves along a neural pathway rendered dysfunctional by a given disease is potentially a valuable clinical tool.

Behavioral improvement in a primate Parkinson's model is associated with multiple homeostatic effects of human neural stem cells.

Stem cells have been widely assumed to be capable of replacing lost or damaged cells in a number of diseases, including Parkinson's disease (PD), in which neurons of the substantia nigra (SN) die and fail to provide the neurotransmitter, dopamine (DA), to the striatum. We report that undifferentiated human neural stem cells (hNSCs) implanted into 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated Parkinsonian primates survived, migrated, and had a functional impact as assessed quantitatively by behavioral improvement in this DA-deficit model, in which Parkinsonian signs directly correlate to reduced DA levels. A small number of hNSC progeny differentiated into tyrosine hydroxylase (TH) and/or dopamine transporter (DAT) immunopositive cells, suggesting that the microenvironment within and around the lesioned adult host SN still permits development of a DA phenotype by responsive progenitor cells. A much larger number of hNSC-derived cells that did not express neuronal or DA markers was found arrayed along the persisting nigrostriatal path, juxtaposed with host cells. These hNSCs, which express DA-protective factors, were therefore well positioned to influence host TH+ cells and mediate other homeostatic adjustments, as reflected in a return to baseline endogenous neuronal number-to-size ratios, preservation of extant host nigrostriatal circuitry, and a normalizing effect on alpha-synuclein aggregation. We propose that multiple modes of reciprocal interaction between exogenous hNSCs and the pathological host milieu underlie the functional improvement observed in this model of PD.

Neural stem cells implanted into MPTP-treated monkeys increase the size of endogenous tyrosine hydroxylase-positive cells found in the striatum: a return to control measures.

Neural stem cells (NSC) have been shown to migrate towards damaged areas, produce trophic factors, and replace lost cells in ways that might be therapeutic for Parkinson's disease (PD). However, there is very little information on the effects of NSC on endogenous cell populations. In the current study, effects of implanted human NSC (hNSC) on endogenous tyrosine hydroxylase-positive cells (TH+ cells) after treatment with 1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine (MPTP) were explored in nonhuman primates. After MPTP damage and in PD, the primate brain is characterized by decreased numbers of dopamine neurons in the substantia nigra (SN) and an increase in neurons expressing TH in the caudate nucleus. To determine how implanted NSC might affect these cell populations, 11 St. Kitts African green monkeys were treated with the selective dopaminergic neurotoxin, MPTP. Human NSC were implanted into the left and right caudate nucleus and the right SN of eight of the MPTP-treated monkeys. At either 4 or 7 months after NSC implants, the brains were removed and the size and number of TH+ cells in the target areas were assessed. The results were compared to data obtained from normal untreated control monkeys and to the three unimplanted MPTP-treated monkeys. The majority of hNSC were found bilaterally along the nigrostriatal pathway and in the substantia nigra, while relatively few were found in the caudate. In the presence of NSC, the number and size of caudate TH+ cells returned to non-MPTP-treated control levels. MPTP-induced and hNSC-induced changes in the putamen were less apparent. We conclude that after MPTP treatment in the primate, hNSC prevent the MPTP-induced upregulation of TH+ cells in the caudate and putamen, indicating that hNSC may be beneficial to maintaining a normal striatal environment.

Effects of perceived treatment on quality of life and medical outcomes in a double-blind placebo surgery trial.

CONTEXT: This study was part of a large double-blind sham surgery-controlled trial designed to determine the effectiveness of transplantation of human embryonic dopamine neurons into the brains of persons with advanced Parkinson's disease. This portion of the study investigated the quality of life (QOL) of participants during the 1 year of double-blind follow-up. OBJECTIVES: To determine whether QOL improved more in the transplant group than in the sham surgery group and to investigate outcomes at 1 year based on perceived treatment (the type of surgery patients thought they received). DESIGN: Participants were randomly assigned to receive either the transplant or sham surgery. Reported results are from the 1-year double-blind period. SETTING: Participants were recruited from across the United States and Canada. Assessment and surgery were conducted at 2 separate university medical centers. PARTICIPANTS: A volunteer sample of 40 persons with idiopathic Parkinson's disease participated in the transplant ("parent") study, and 30 agreed to participate in the related QOL study: 12 received the transplant and 18 received sham surgery. INTERVENTIONS: Interventions in the parent study were transplantation and sham brain surgery. Assessments of QOL were made at baseline and 4, 8, and 12 months after surgery. MAIN OUTCOME MEASURES: Comparison of the actual transplant and sham surgery groups and the perceived treatment groups on QOL and medical outcomes. We also investigated change over time. RESULTS: There were 2 differences or changes over time in the transplant and sham surgery groups. Based on perceived treatment, or treatment patients thought they received, there were numerous differences and changes over time. In all cases, those who thought they received the transplant reported better scores. Blind ratings by medical staff showed similar results. CONCLUSIONS: The placebo effect was very strong in this study, demonstrating the value of placebo-controlled surgical trials.