Search

Potentially druggable mechanisms underlying synaptic deficits seen in Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are under intense interrogations. In addition to defective synaptic vesicle trafficking, cytoskeletal disruption, autophagic perturbation, and neuroinflammation, hyperphosphorylation of microtubule-associated protein collapsin response mediator protein 2 (CRMP2, also known as DPYSL2) is newly determined to correlate with synaptic deficits in human DLB. The small molecule experimental therapeutic, lanthionine ketimine-5-ethyl ester (LKE), appears to interact with CRMP2 in a host of neurodegenerative mouse models, normalizing its phosphorylation level while promoting healthful autophagy in cell culture models and suppressing the proinflammatory phenotype of activated microglia. Accordingly, this study examined the effect of LKE on α-synuclein A53T transgenic (Tg) mice which were employed as a DLB model. We found that chronic administration of LKE to A53T mice suppressed (1) the accumulation of LBs, (2) neuroinflammatory activation of microglia, (3) impairment of contextual fear memory, and (4) CRMP2 phosphorylation at Thr509 in A53T Tg mice. These results suggest that CRMP2 phosphorylation by GSK3β in the hippocampus is related to pathology and memory impairment in DLB, and LKE may have clinical implications in the treatment of α-synucleinopathy., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The mammalian central nervous system (CNS) has limited regenerative ability after injury, largely due to scar formation and axonal growth inhibitors. Experimental suppression of neuroinflammation encourages recovery from spinal cord injury (SCI), yet practical means for pharmacologically treating SCI have remained elusive. Lanthionine ketimine (LK) is a natural brain sulfur amino acid metabolite with demonstrated anti-neuroinflammatory and neurotrophic activities. LK and its synthetic brain-penetrating ethyl ester (LKE) promote growth factor-dependent neurite extension in cultured cell and suppress microglial activation in animal models of neurodegeneration. Thus far however, LKE has not been explored as a potential therapy for SCI. The present study investigated the hypothesis that systemic LKE could improve motor functional recovery after SCI in a mouse model. Intraperitoneal administration of LKE (100 mg/kg/d) after near-complete transect of spinal cord at the T7 level significantly improved motor function over a 4-week time course. Vehicle-treated mice, in contrast, demonstrated negligible functional recovery. In terms of histology, LKE treatment reduced pro-neuroinflammatory microglia/macrophage activation evidenced by quantitative Iba1 labeling and shifted the microglial phenotype toward a more neurotrophic M2 character evidenced by changes in the M2 marker arginase-1. This was correlated with less dense scar formation and more extensive axonal regrowth across the transection site demonstrated by 5-hydroxytryptamine (5HT) immunolabeling of raphespinal tract axons. These data provide evidence that LKE or similar compounds have potential therapeutic value for recovery after certain forms of SCI., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Lanthionine ketimine ([LK] 3,4-dihydro-2H-1,4-thiazine-3,5-dicarboxylic acid) is the archetype for a family of naturally occurring brain sulfur amino acid metabolites, the physiologic function of which is unknown. Lanthionine ketimine and its synthetic derivatives have recently demonstrated neurotrophic, neuroprotective, and antineuroinflammatory properties in vitro through a proposed mechanism involving the microtubule-associated protein collapsin response mediator protein 2. Therefore, studies were undertaken to test the effects of a bioavailable LK ester in the 3 × Tg-AD mouse model of Alzheimer disease. Lanthionine ketimine ester treatment substantially diminished cognitive decline and brain amyloid-β (Aβ) peptide deposition and phospho-Tau accumulation in 3 × Tg-AD mice and also reduced the density of Iba1-positive microglia. Furthermore, LK ester treatment altered collapsin response mediator protein 2 phosphorylation. These findings suggest that LK may not be a metabolic waste but rather a purposeful neurochemical, the synthetic derivatives of which constitute a new class of experimental therapeutics for Alzheimer disease and related entities.

Lanthionine ketimine (LK) is a natural sulfur amino acid metabolite with potent neurotrophic activity. Proteomics indicate that LK interacts with collapsin response mediator protein-2 (CRMP2/DPYSL2/UNC-33), a brain-enriched protein that was shown to regulate cytoskeletal remodeling, neuronal morphology, and synaptic function. To elucidate further the molecular interplay and biological action of LK and UNC-33, we began examining the nervous system of Caenorhabditis elegans nematodes in which both LK concentrations and UNC-33 protein were manipulated. To this end, a cell-permeable LK-ester (LKE) was administered to developing C. elegans engineered to express yellow fluorescent protein (YFP) in cholinergic neurons (strain RM3128) or green fluorescent protein (GFP) in GABAergic neurons (strain CZ1200), and neural morphology was assessed. Fluorescent imaging analyses show that LKE exposure to wild-type animals induced neural commissure outgrowth, crossing over, and bundling in both neurites from GABAergic and cholinergic motor neurons. Additionally, when unc-33(e204) hypomorph mutant nematodes (D389N substitution mutants) were exposed to LKE, both the neuroanatomical defects of incomplete dorsoventral neural commissures and the ventral nerve cord gaps were partially rescued. In contrast, LKE did not rescue ventral nerve cord gaps found in unc-33(mn407) null mutant. Together these data suggest possible functions for LK as a regulator of neuritic elongation, corroborate roles for UNC-33/CRMP2 in the mechanism of LKE activity, and suggest the potential of LKE as a therapeutic molecule for neurological diseases involving CRMP2 dysfunction., (Copyright © 2013 Wiley Periodicals, Inc.)

Lanthionines are novel neurotrophic and neuroprotective small molecules that show promise for the treatment of neurodegenerative diseases. In particular, a recently developed, cell permeable lanthionine derivative known as LKE (lanthionine ketimine 5-ethyl ester) promotes neurite growth at low nanomolar concentrations. LKE also has neuroprotective, anti-apoptotic, and anti-inflammatory properties. Its therapeutic potential in cerebral ischemia and its mechanisms of neurotrophic action remain to be fully elucidated. Here, we hypothesize that the neuroprotective actions of LKE could result from induction or modulation of CRMP2. We found that treating primary cultured mouse neurons with LKE provided significant protection against t-butyl hydroperoxide-induced neuronal death possibly through CRMP2 upregulation. Similarly, in vivo studies showed that LKE pre and/or post-treatment protects mice against permanent distal middle cerebral artery occlusion (p-MCAO) as evidenced by lower stroke lesions and improved functional outcomes in terms of rotarod, grip strength and neurologic deficit scores in treated groups. Protein expression levels of CRMP2 were higher in brain cortices of LKE pretreated mice, suggesting that LKE's neuroprotective activity may be CRMP2 dependent. Lower activity of cleaved PARP-1 and higher activity of SIRT-1 was also observed in LKE treated group suggesting its anti-apoptotic properties. Our results suggest that LKE has potential as a therapeutic intervention in cerebral ischemia and that part of its protective mechanism may be attributed to CRMP2 mediated action and PARP-1/SIRT-1 modulation., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The side effects in myelography are well known and frequently observed. The most common are headache, nausea, and vomiting. In this study, a rather new compound, Thiorphan, was examined, which displays an antinociceptive activity by inhibiting enkephalinase activity. Forty-two patients received intravenous infusions of Thiorphan before myelography. Another 42 patients were in a control group, and Thiorphan was not administered. In the treated group, postmyelographic headache was found in 24% (versus 52% in the control group). Nausea and vomiting were never seen. Low back pain or sciatica was diminished in 33% of cases. Enkephalin levels in cerebrospinal fluid were measured by a radioreceptor-assay method in both groups without any correlation.

A study of patients with rheumatoid arthritis permitted us to note the interest of tiopronine (sulfhydryl compound of the d-penicillamine type) in the basic treatment of rheumatoid arthritis. The dose of the drug was on average, 1 gram daily, which, in one series of patients, was administered at the start of treatment and in another series, with an increase of dosage of 250 mg every 20 days. The results, judged by the reduction of the Ritchie and Lee index, of the E.R.S. and the steroid and non-steroid anti-inflammatory requirements, are good (very good and good) in 47% of cases. These patients were in an advanced stage of the disease and there had been numerous therapeutic failures. Side effects similar to those observed during treatment with D-penicillamine were present in 38% of cases, and in 31% required stopping treatment. It is likely that the frequency of stopping treatment for side effects was definitely exaggerated. The place of this new drug in the basic treatment of rheumatoid arthritis requires further study by a double blind test with D-penicillamine, and this is at present in progress.

"In vivo" and "in vitro" action of 2 MPG on lymphocytotoxic activity was evaluated in 22 patients with CAH, 14 were HBsAg positive and 8 were negative. The test was performed with and without 2 MPG in the colture medium, and before and after treatment. HBsAg+ patients received 2 MPG treatment, while HBsAg- ones received immunosoppressive therapy and 4 of these were on 2 MPG treatment as well. Cytotoxic Index was reduced non-significantly by addition of 2 MPG in colture medium in both groups. 2 MPG treatment does not modify cytotoxic activity which is reduced by immunosoppressive therapy. These findings suggest a positive effect of 2 MPG on liver-cell metabolism with an increased resistence of the epatocyte to the "in vitro" lymphocytes aggression. Hence it may be suggested an association treatment with immunosoppressive agents and 2 MPG.

Myocardial reperfusion after reversible regional ischemia is known to result in delayed recovery of contractile function, but the mechanism responsible for this phenomenon remains unclear. We examined the ability of N-2-mercaptopropionylglycine, a synthetic thiol compound with oxygen free radical scavenging properties, to attenuate postischemic dysfunction in open chest dogs undergoing a 15 minute occlusion of the left anterior descending coronary artery followed by 4 hours of reperfusion. Treated animals received an infusion of N-2-mercaptopropionylglycine (50 mg/kg per h) for 4 hours starting 15 minutes before coronary occlusion. Collateral flow, as determined with radioactive microspheres after 10 minutes of ischemia, was 0.07 +/- 0.01 ml/min per g (mean +/- SE) in both control (n = 20) and treated (n = 13) groups. The occluded vascular bed, as determined by postmortem perfusion, averaged 26.1 +/- 1.2% of the weight of the left ventricle in control and 29.6 +/- 1.3% in treated animals. Systolic wall thickening (an index of regional function) was assessed with an epicardial pulsed Doppler probe. The two groups exhibited comparable systolic thickening under baseline conditions and similar degrees of dyskinesia during ischemia. Nevertheless, recovery of function (expressed as percent of baseline) was considerably greater in the treated dogs at 1 hour (44.6 versus 12.8%, p = 0.05), 2 hours (64.0 versus 31.6%, p less than 0.02), 3 hours (77.1 versus 36.7%, p less than 0.01) and 4 hours of reperfusion (75.0 versus 40.0%, p less than 0.05). Thus, N-2-mercaptopropionylglycine produced a significant and sustained improvement in recovery of contractile function after a brief episode of regional myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

The authors report the first results of the use of mercaptopropionyl-glycine (M.P.G.) in the solubilising and preventive treatment of cystine lithiasis. This substance results in the formation of a soluble cystine M.P.G. complex. It increases the solubility of cystine much more than D-penicillinamine. Twenty one cases of cystinuric cystine lithiasis were treated in this way, combined with forced diuresis, alkalinisation of the urine and uricolytic treatment. In 4 of their 21 patients, calculi disappeared completely, whilst in another 3 they decreased in size. Recurrence of lithiasis was avoided in 20 patients out of 21. These impressive results are similar to those in the brief literature concerned with the substance. Toxicity is virtually nil and its efficacy make this the drug par excellence for cystine lithiasis.

Effects of oral administration of tiopronin (2-mercaptopropionylglycine) on acute liver damage induced in rats by intraperitoneal administration of carbon tetrachloride (CCl4) were investigated. Tiopronin suppressed increase in serum transaminase activity, accumulation of liver triglyceride and decrease of liver glucose-6-phosphatase activity induced by CCl4. CCl4 induced a significant decrease of nonprotein thiol (NPSH) in the liver 24 hr after administration, but this decrease did not result in an increase of nonprotein disulfide in the liver. Tiopronin suppressed the decrease in NPSH induced by CCl4, but did not influence NPSH in normal rats 24 hr after administration. In addition to these biochemical findings, it was also noted that tiopronin prevented necrosis and decrease of glycogen in liver, as determined histologically. Other compounds such as cystamine, cysteine and glutathione proved to have a preventive effect on CCl4-induced liver damage as in the case of tiopronin. It was revealed that such preventive effect correlated to some extent with NPSH content in liver as well as serum transaminase activity and histological findings.

The effectiveness of alpha-MPG management was evaluated in terms of changes in the liver cell depuration fraction in patients who presented reduced a levels. There was a marked improvement occasionally to the point of normalisation, in patients with toxic hepatosis. Variations were less significant in cirrhosis, especially in patients with a very low liver metabolism flow. No conclusions could be draw in the case of subjects with chronic heaptitis of various aetiology, since their DF was normal under basal conditions. It seems reasonable to suppose that further improvements are obtainable from prolonged administration of the drug.

Prophylactic measures or dissolution by medical therapy was used to treat bladder cystine stones in 14 children over about a 10-year period. All patients received alpha-MPG (alpha-mercaptopropionylglycine) except one child allergic to alpha-MPG who was treated with DNP (D-penicillamine). In 10 patients the treatment was administered 11 times to dissolve the stones, with resulting total dissolution in 6 cases, partial removal in one case. Two patients are still under treatment and 2 cases failed to respond. Among the 12 patients receiving preventive therapy, only 2 cases were reported as developing recurrences, due in fact to irregular taking of medication. Lytic treatment proceeded without any particular problems, and results were more than satisfactory, but for preventive therapy the difficulty resides in its application and duration when confronted with the serious and frequent danger of a relapse.

2 mercapto propionyl glycine (tiopronine) has, like D-penicillamine, a thiol radicle; it is a powerful chelating agent of heavy metals. This analogy suggests that it may be used in rheumatoid arthritis. A preliminary double blind study lasting four months comparing 1g./day in 20 patients and a placebo in 10 patients showed slight (non significant) efficacy concerning all parameters. An open study using 1.5 g. daily is being carried out in 32 patients, and we note a beneficial effect on the morning stiffness, the joint index, the functional index, the prehension strength, the E.S.R., and the joint swelling. The side effects are similar to those of D-penicillamine: loss of taste, proteinuria, mucous ulceration, which required stopping treatment. The therapeutic effect within 4 months and was maintained for 18 months in the 15 patients under treatment. A new double blind trial comparing placebo and tiopronine at a dose of 1.5 g. daily is in progress.

Contents of high energy phosphates in the isolated perfused rat heart were followed during ischemia and reperfusion using 31P NMR spectroscopy. Application of 2-mercaptopropionylglycine resulted in significantly higher content of ATP in the reperfusion phase whereas during ischemia no differences between control and therapy hearts were found. Analysis of postischemic mitochondrial function reveals that improved ATP level is paralleled by an increased respiratory control index and a reduced ATPase activity. It is suggested that 2-mercaptopropionylglycine may cause increase of high energy phosphates during reperfusion by improving mitochondrial oxidative phosphorylation.

7 children, 20 months to 11 years old, with cystinuria and renal calculi were studied. Surgical treatment and alpha-mercaptopropionylglycine (MPG) gave satisfactory results in 5 children. The causes of the recurrences in the other 2 children are discussed. MPG therapy is effective but can cause a nephrotic syndrome at a dose of more than 50 mg/kg/day. A cystinuria of less than 200 mg/day cannot always be considered safe in children. The alkalinization and dilution of urine remain extremely important in the treatment of cystinuria.

Sixteen patients with cystinuria have been treated with Thiola for 0.5-4 years. Only two of the patients had recurrence of stones because of initial inadequate dose. The excretion of free cystine and the mixed Thiola-cysteine disulphide in the urine has been measured on an automatic amino acid analyser. Thiola has less side effects than D-penicillamine with respect to bone marrow, kidney, liver, gastrointestinal tract and skin. No chelating properties on urinary excretion of copper and zinc were observed during Thiola treatment. We conclude that successful treatment will depend on determining an individual dose of Thiola for every patient and from monitoring free cystine and Thiola-cysteine disulphide in the urine.

Cystinuria is an inherited disorder of amino acid transport affecting the epithelial cells of the renal tubules and the gastro-intestinal tract. Treatment consists of the prophylaxis of recurrent urolithiasis, which is the clinical manifestation of the disease. Long-term treatment with alpha-mercapto-propionyl-glycine (MPG; Thiola) promises to be successful. 3 cytinuric patients with recurrent urolithiasis underwent treatment over a period of 6 months. Therapy was controlled by regular follow-up investigations of the urinary excretion and serum levels of cystine and di-basic amino acids. The results did not indicate any permanent decrease in cystine excretion. No recurrence of renal calculi was observed. The possibility is discussed of a direkt mechanism of action of the drug on the metabolism of the involved amino acids.

We have compared 2-mercaptopropionylglycine (MPG) with D-penicillamine in its capacity to reduce the urinary excretion of cystine by patients with cystinuria. Satisfactory ion-exchange chromatographic methods for the measurement of urinary MPG, D-penicillamine, cystine and the cysteine-disulfides of the two drugs have been developed, and we have established the time course of the excretion of these substances after oral intake of each drug. MPG was found to be approximately one and a half times as effective as D-penicillamine, both in reducing urinary excretion of free cystine and in the amounts of mixed disulfide which appeared in the urine.

The effects of 60 min pretreatment with the enkephalinase inhibitor acetorphan were assessed on naloxone-precipitated (2.5 mg/kg IP) abstinence in chronically morphinized rats. In addition, the antinociceptive activity of the compound was investigated in mice. Intraperitoneal injection (50 mg/kg) in rats attenuated some aspects of the opioid withdrawal syndrome such as burrowing, wet dog shakes, squeal on touch hostility, tachypnoea, ptosis and rough hair, whereas jumping and escape behaviour were significantly increased in acetorphan-treated animals. No effect was observed on withdrawal hypothermia or acute weight loss. Similarly, chronic dosing with acetorphan after withdrawal produced no significant effect on body weight. Acetorphan (50 mg/kg IP) failed to produce any antinociceptive activity in the mouse tail immersion test, but potentiated the antinociceptive effect of D-Ala2-D-Leu5-enkephalin. These results are discussed in terms of acetorphan crossing the blood-brain barrier before being hydrolysed to thiorphan, thus yielding opioid withdrawal relieving effects.

The results of using alpha-mercapto-propionyl-glycine treatment (500 mg i.v. pro die for a time varying from one to four months) in a group of 25 patients suffering from aregenerative enteropathy with differing aetiopathogenesis are reported and compared with 29 control patients, i.e. patients suffering from the same situation and not treated with the drug. Morphological (by optical and electronic microscope) and functional (absorption of oleic acid, xylose and B12) study of the small intestine showed up the effectiveness of alpha-mercapto-propionyl-glycine on the trophism of small intestine mucosa, by way of normalization of intestinal cytokinetics, in aregenerative enteropathies due to special physiopathological situations (gastroresection) or to drugs (cytostatics, etc.) inhibiting enterocytic regeneration.

Some parameters (serum antioxidant activity, -SH groups, ceruloplasmin, copper) involved in the mechanisms of defence against oxygen free radicals were investigated in 25 rheumatoid patients and in 15 control subjects, matched for sex and age. When comparing the results obtained in the two groups, there is in rheumatoid arthritis a marked increase in the serum-specific antioxidant activity, related to ceruloplasmin, ESR, haemoglobin and Ritchie's index and a net decrease in the -SH groups inversely related to Ritchie's index and to ceruloplasmin. On analysing the sensitivity of the various parameters in discriminating between rheumatoid and healthy subjects, it is found that the -SH groups are the most sensitive, followed by the specific antioxidant activity, copper content, and ceruloplasmin. The evaluation of the same parameters in a group of 14 rheumatoid patients before and after 6 months of therapy with an antioxidant drug, viz. Tiopronin, confirms their usefulness in providing information regarding response to the treatment and on the recovery from the disease.

Arginine and large doses of glutamate (greater than 500 mg/kg) were found to reduce ammonia toxicity transiently in mice. Smaller doses of glutamate (greater than or equal to 200 mg/kg) were effective when administered with glucose. Cysteic acid, homocysteine and methionine, but not taurine reduced ammonia toxicity. All 4 amino acids reduced the number of convulsions induced by methionine sulphoximine. It is proposed that taurine has a general anticonvulsant action and that cysteic acid, homocysteine and methionine may have a specific effect on the action of ammonia on the central nervous system.

The therapeutic effect of tiopronin on incipient senile cataracts was evaluated in 150 cases (275 eyes) by a double-blind study using nonactive placebo. A more favorable tendency to visual acuity was noted in the tiopronin than in the placebo group. The slit-lamp microscopic findings showed a statistically significant difference between the tiopronin and the placebo groups. Integrated judgement revealed tiopronin to be significantly effective as compared with the placebo. A side effect of fever with systemic eruption was observed in 1 case in the tiopronin group but disappeared completely when administration of the drug was discontinued.

The effect of long-term treatment with alpha-mercaptopropionylglycine was examined in 66 patients with cystinuria. Of the patients 49 took D-penicillamine before therapy, whereas 17 did not. Over-all side effects to alpha-mercaptopropionylglycine were common, and occurred in 75.5 per cent of the patients with and 64.7 per cent without a history of D-penicillamine treatment, compared to 83.7 per cent who suffered toxicity to D-penicillamine. Serious adverse reactions requiring cessation of therapy were less common with alpha-mercaptopropionylglycine. Among the patients who took both drugs 30.6 per cent had to stop taking alpha-mercaptopropionylglycine, whereas 69.4 per cent could not tolerate D-penicillamine. Of the latter group with toxicity to D-penicillamine before therapy, whereas 17 did therapy only 5.9 per cent had side effects to alpha-mercaptopropionylglycine of sufficient severity to require withdrawal. Alpha-mercaptopropionylglycine was equally as effective as D-penicillamine in reducing cystine excretion. During long-term treatment with alpha-mercaptopropionylglycine (average dose 1,193 mg. per day) urinary cystine levels were maintained at 350 to 560 mg. per day and urinary cystine was kept at undersaturated levels. Commensurate with these changes, alpha-mercaptopropionylglycine produced remission of stone formation in 63 to 71 per cent of the patients and reduced individual stone formation rate in 81 to 94 per cent. Thus, alpha-mercaptopropionylglycine has a definite therapeutic role in cystinuric patients with toxicity to D-penicillamine.