Transplantation of Human Neural Progenitor Cells (NPC) into Putamina of Parkinsonian Patients: A Case Series Study, Safety and Efficacy Four Years after Surgery

Individuals with Parkinson’s disease (PD) suffer from motor and mental disturbances due to degeneration of dopaminergic and non-dopaminergic neuronal systems. Although they provide temporary symptom relief, current treatments fail to control motor and non-motor alterations or to arrest disease progression. Aiming to explore safety and possible motor and neuropsychological benefits of a novel strategy to improve the PD condition, a case series study was designed for brain grafting of human neural progenitor cells (NPCs) to a group of eight patients with moderate PD. A NPC line, expressing Oct-4 and Sox-2, was manufactured and characterized. Using stereotactic surgery, NPC suspensions were bilaterally injected into patients’ dorsal putamina. Cyclosporine A was given for 10 days prior to surgery and continued for 1 month thereafter. Neurological, neuropsychological, and brain imaging evaluations were performed pre-operatively, 1, 2, and 4 years post-surgery. Seven of eight patients have completed 4-year follow-up. The procedure proved to be safe, with no immune responses against the transplant, and no adverse effects. One year after cell grafting, all but one of the seven patients completing the study showed various degrees of motor improvement, and five of them showed better response to medication. PET imaging showed a trend toward enhanced midbrain dopaminergic activity. By their 4-year evaluation, improvements somewhat decreased but remained better than at baseline. Neuropsychological changes were minor, if at all. The intervention appears to be safe. At 4 years post-transplantation we report that undifferentiated NPCs can be delivered safely by stereotaxis to both putamina of patients with PD without causing adverse effects. In 6/7 patients in OFF condition improvement in UPDRS III was observed. PET functional scans suggest enhanced putaminal dopaminergic neurotransmission that could correlate with improved motor function, and better response to L-DOPA. Patients’ neuropsychological scores were unaffected by grafting. Trial Registration: Fetal derived stem cells for Parkinson’s disease https://doi.org/10.1186/ISRCTN39104513Reg#ISRCTN39104513

Changes in renal function during acute spinal cord injury: implications for pharmacotherapy

STUDY DESIGN

Laboratory investigation in rats submitted to experimental spinal cord injury (SCI).

OBJECTIVE

To characterize changes in renal function during acute SCI.

METHODS

Sprague Dawley rats were subjected to severe spinal cord contusion at T8 level or to laminectomy as control. Twenty-four hours after spine surgery, clearance assessments of a single dose of iohexol (120 mg kg(-1)) or of p-aminohippuric acid (PAH, 100 mg kg(-1)) were used to evaluate glomerular filtration rate (GFR) and tubular secretion (TS), respectively. Blood sampling was used to determine concentrations of both compounds by high-performance liquid chromatography for pharmacokinetic measurements.

RESULTS

Iohexol clearance decreased significantly after injury, which resulted in increased concentrations and half-life of iohexol in blood; PAH clearance remained unchanged.

CONCLUSION

GFR but not TS is altered during spinal shock. These observations should be of interest to professionals caring for early cord-injured patients, in order to prevent toxicity and therapeutic failure when administering drugs eliminated by the kidney.

Acute spinal cord injury changes the disposition of some, but not all drugs given intravenously

STUDY DESIGN

Experimental laboratory investigations in paraplegic rats.

OBJECTIVE

In order to understand why acute spinal cord injury (SCI) changes the disposition of some, but not all drugs given intravenously (i.v.), pharmacokinetic parameters of drugs with different pharmacological properties were evaluated to determine the influence of SCI on physiological processes such as distribution, metabolism and excretion.

SETTING

Mexico City, Mexico.

METHODS

Rats were subjected to severe SCI (contusion) at T-9 level; pharmacokinetic studies of phenacetin, naproxen or gentamicin were performed 24 h after. These drugs were not chosen as markers because of their therapeutic properties, but because of their pharmacokinetic characteristics. Additional studies including plasma proteins, liver and renal function tests, and micro-vascular hepatic blood flow, were also performed at the same time after injury.

RESULTS

Acute SCI significantly reduced distribution of drugs with intermediate and low binding to plasma proteins (phenacetin 30% and gentamicin 10%, respectively), but distribution did not change when naproxen - a drug highly bound to plasma proteins (99%) - was used, in absence of changes in plasma proteins. Metabolism was significantly altered only for a drug with liver blood flow - limited clearance (phenacetin) and not for a drug with liver capacity-limited clearance (naproxen). The liver function test did not change, whereas the hepatic micro-vascular blood flow significantly decreased after SCI. Renal excretion, evaluated by gentamicin clearance, was significantly reduced as a consequence of SCI, without significant changes in serum creatinine.

CONCLUSIONS

Changes in drug disposition associated to acute SCI are complex and generalization is not possible. They are highly dependent on each drug properties as well as on the altered physiological processes. Results motivate the quest for strategies to improve disposition of selective i.v. drugs during spinal shock, in an effort to avoid therapeutic failure.

Glutathione monoethyl ester improves functional recovery, enhances neuron survival, and stabilizes spinal cord blood flow after spinal cord injury in rats

Secondary damage after spinal cord (SC) injury remains without a clinically effective drug treatment. To explore the neuroprotective effects of cell-permeable reduced glutathione monoethyl ester (GSHE), rats subjected to SC contusion using the New York University impactor were randomly assigned to receive intraperitoneally GSHE (total dose of 12 mg/kg), methylprednisolone sodium succinate (total dose of 120 mg/kg), or saline solution as vehicle. Motor function, assessed using the Basso-Beattie-Bresnahan scale for 8 weeks, was significantly better in GSHE (11.2+/-0.6, mean+/-S.E.M., n=8, at 8 weeks) than methylprednisolone (9.3+/-0.6) and vehicle (9.4+/-0.7) groups. The number of neurons in the red nuclei labeled with FluoroRuby placed caudally to the injury site was significantly higher in GSHE (158+/-9.3 mean+/-S.E.M., n=4) compared with methylprednisolone (53+/-14.7) and vehicle (46+/-16.4) groups. Differences in the amount of spared SC tissue at the epicenter and neighboring areas were not significant among experimental groups. In a second series of experiments, using similar treatment groups (n=6), regional changes in microvascular SC blood flow were evaluated for 100 min by laser-Doppler flowmetry after clip compression injury. SC blood flow fell in vehicle-treated rats 20% below baseline and increased significantly with methylprednisolone approximately 12% above baseline; changes were not greater than 5% in rats given GSHE. In conclusion, GSHE given to rats early after moderate SC contusion/compression improves functional outcome and red nuclei neuron survival significantly better than methylprednisolone and vehicle, and stabilizes SC blood flow. These results support further investigation of reduced glutathione supplementation after acute SC injury for future clinical application.

Sympathetic blockade significantly improves cardiovascular alterations immediately after spinal cord injury in rats

Immediately after an experimental spinal cord injury (SCI) in rats, there is a large fall in mean arterial pressure (MAP) and heart rate (HR), followed by an abrupt increase in MAP. To better understand the mechanism involved in these early cardiovascular alterations, we tested the effect of treatment with ganglionic and sympathetic blockers in anesthetized rats subjected to T-5 SCI. Fall in MAP was partially diminished by propranolol and pentolinium, while increase in MAP was abolished by propranolol and pentolinium. Adrenalectomy did not diminish the fall in MAP and HR, however, the increase in MAP was significantly reduced. Likewise, propranolol and pentolinium completely abolished the effects in HR. These data suggest that the early cardiovascular alterations secondary to SCI results from an increased parasympathetic activity and a sympathetic withdrawal.

Mechanisms involved in the cardiovascular alterations immediately after spinal cord injury

The early cardiovascular effects resulting from an acute spinal cord injury (SCI) produced by a contusion procedure at T5-T6 were evaluated in anaesthetized rats. The mean arterial pressure (MAP) and heart rate (HR) were measured during one hour after the injury. A marked decrease in MAP and HR was observed immediately after injury, followed by an abrupt increase in MAP. These changes were observed between 3 and 9 min and the basal values were recovered after 20 min. Fall in the MAP and HR and increase in MAP induced by SCI were abolished by atropine. The interruption of the parasympathetic outflow by vagotomy also significantly diminished the fall and increase in MAP and the fall in HR. Likewise, pre-treatment with nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) completely abolished the effects produced by SCI. These data suggest that after SCI the decrement in MAP and HR was probably due to acetylcholine release from parasympathetic fibers and NO from endothelial source probably by a cholinergic stimulation. Additionally, the MAP increase observed was probably due to a reflex compensatory vasoconstriction.

Effect of experimental spinal cord injury on salicylate bioavailability after oral aspirin administration

The purpose of the present work was to study whether spinal cord injury (SCI) alters salicylate bioavailability after oral aspirin administration. Female Sprague-Dawley rats were subjected to SCI at the T8 level by two procedures, contusion by the weight-drop method and severance by knife, and received a single oral aspirin dose (15 mg/kg) 24 h after injury. Blood samples were drawn and aspirin (ASA) and salicylic acid (SA) concentrations in whole blood were determined at selected times over a period of 240 min. Both SCI procedures produced similar alterations on salicylate bioavailability. ASA bioavailability was not significantly changed by SCI. On the other hand, SA peak concentrations were significantly reduced in 20% to 30%, compared with sham-lesioned controls. The area under the SA concentration against time curve was decreased in 10% to 25%, although this difference did not reach statistical significance. Results suggest that SCI at the T8 level decreases the rate, but not the extent, of aspirin absorption from the gastrointestinal tract. SCI-induced alterations in aspirin absorption appeared to be modest compared with those previously reported for other analgesic agents, such as paracetamol (acetaminophen).

Early changes in nitric oxide synthase activity in atrial intramural arteries following experimental spinal cord injury in rats

Previously, we have shown that immediately after an experimental spinal cord injury (SCI) in anaesthetized rats, there is a large fall in mean arterial pressure (MAP) and heart rate (HR), followed by an abrupt increase in MAP. To evaluate the participation of nitric oxide (NO), we evaluated the activity of nitric oxide synthase (NOS) using Nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemistry in sections of atria at several post-injury time-intervals. Staining increased at 3 min, reached a maximum at 9 min and diminished 30 min after injury. Pretreatment with atropine prevented changes in MAP, HR and NADPH-d staining suggesting that such modifications result from an increased vagal stimulation. In conclusion, the NOS activity is transiently elevated in the atrial intramural arteries of rats subjected to an SCI.

Transitory expression of NADPH diaphorase (NOS) in axonal swellings after spinal cord injury

To investigate the sites of nitric oxide synthase (NOS) expression after a spinal cord (SC) injury, NADPH-d diaphorase histochemistry was performed in the SC of adult rats sacrificed at different times from 1 h to 90 days after both SC contusion or transection. NOS could first be seen 12 h after injury in axonal swellings (AS) (club shaped structures at the tip of damage axons, associated with tissue destruction). NOS expression reached a maximum 3 days after injury, and gradually disappeared after 7 days. Finally, AS collapsed leaving behind microcysts. NOS expression and the consequent production of nitric oxide could be involved in the pathophysiology of the secondary damage, and/or could reflect a failed attempt for axonal regeneration.

Oral paracetamol bioavailability in rats subjected to experimental spinal cord injury

The purpose of the present study was to examine the time dependence of oral paracetamol (acetaminophen) bioavailability in an experimental model of spinal cord injury (SCI). Female Sprague-Dawley rats were subjected to spinal cord contusion at the T8-T9 level by the weight drop method producing permanent paraplegia. Oral paracetamol bioavailability after administration of a single 100 mgkg-1 dose was determined 1, 12, and 50 d after SCI. Cmax and AUC were significantly decreased 1 d after SCI compared to sham-injured controls. This reduction, however, was temporary, as there was a recovery of bioavailability parameters which was partial 12 d after SCI, being complete by day 50. The present results confirm the usefulness of animal models for the characterization of the effect of SCI in drug kinetics. Data show that SCI induces significant changes in paracetamol pharmacokinetics. Nonetheless, despite the fact of a permanent loss of functions related to locomotion, pharmacokinetic alterations evolved with time.

Use of cyclosporin-A in experimental spinal cord injury: design of a dosing strategy to maintain therapeutic levels

Cyclosporin-A (CsA) is frequently used as an immunosuppressive agent in experimental transplantations. CsA has been used in nervous tissue transplants in spinal cord injury (SCI). However, optimal results have not been obtained. This is likely due to the fact that SCI alters CsA pharmacokinetics and hence fixed dose regimens are not adequate. In this study, several CsA dosing regimens were evaluated in Long-Evans female rats subjected to a severe low thoracic (T8) SCI by the contusion method. Serum CsA concentrations were measured to determine which dosing regimen allowed CsA levels to be maintained within the therapeutic window. It was found that administration of 2.5 mg/kg/12 h intraperitoneally during the first 2 days after SCI (acute phase) followed by 5 mg/kg/12 h orally thereafter (subacute and chronic phases) yields CsA circulating levels within the therapeutic window, i.e., 0.120-0.275 microgram/mL. This dosing regimen represents a suitable alternative to fixed dosing to achieve an optimal CsA-induced immunosuppression in experimental models of SCI.

Alteration of cyclosporin-A pharmacokinetics after experimental spinal cord injury

The pharmacokinetics of the immunosuppressive agent cyclosporin-A (CsA) were studied in rats submitted to spinal cord (SC) injury. A single CsA 10 mg/kg dose was given either intraperitoneally (i.p.) or orally to rats submitted to experimental SC injury at the T8 level. Twenty four hours after lesion (acute stage of SC injury) i.p. CsA bioavailability was increased, while t1/2 was prolonged. However, oral bioavailability was reduced. Seven weeks after lesion (chronic stage of SC injury) CsA bioavailability, by either route, was not significantly different from control values. Results indicate that parenteral CsA bioavailability is increased during the acute stage of SC lesion, probably due to an impaired elimination. Oral bioavailability, however, is decreased, since there is also an important reduction in gastrointestinal CsA absorption that overrides the effect of impaired elimination. Alterations in CsA pharmacokinetics appear to revert during the chronic stage of SC injury. Changes in CsA bioavailability, depending on the route of administration and on time, must be considered to design an adequate immunosuppressive treatment in SC injury.

[Human fetal homograft to the nigrostriatal system for the treatment of Parkinson's disease]

Four cases of transplant to the brain (striatum) of the ventral mesencephalic area (VMA) and three adrenal glands (A) to patients with Parkinson's disease are described as a new alternative for the improvement of this disease. The patients who received VMA showed a very significant improvement in the rigidity, bradykinesia, alterations in walking and posture, as well as the facial expression. Three of the four patients have returned to work. The group that received A tissue, showed a discreet improvement in the rigidity and bradykinesia, but none in the other signs of the disease. These patients are able to accomplish their daily needs, but two are unable to return to work. The differences which we observed between patients receiving VMA and A transplants, might be related to the heterogeneity of the disease, although we believe that the type of graft was responsible of these differences. Our results with the use of VMA, as well as that of other groups, are encouraging, although it is important to clearly establish that it is a procedure which is still in an experimental phase, requiring caution, and should only be practiced in highly qualified centers of clinical research.

Balloon needle for the atraumatic transcortical ventricular approach: technical note

We have designed a double-lumen inflatable needle for the atraumatic dissection of brain substance. This balloon needle has been successfully used for the ventricular approach in brain grafting procedures to obtain a rounded corticotomy with a diameter of 1.5-2 cm in the treatment of Parkinson's disease.