TL neuro

June 22, 2018

An oxycodone vaccine prevents the acquisition of self-administration

Filed under: Opiates, Vaccines — mtaffe @ 2:59 pm

A paper from the laboratory has recently been accepted for publication .

Nguyen*, J.D., Hwang*, C.S., Grant, Y., Janda, K.D.. and Taffe, M.A. Prophylactic vaccination protects against the development of oxycodone self-administration.  Neuropharmacology, 2018, 138:292-303. [ Publisher Link ][ Free Author Share ]

This paper reflects joint effort with members of the Janda laboratory in our ongoing collaboration [ related posts ] to evaluate their anti-drug vaccines for efficacy in rat models of drug exposure and abuse. In this study we focused on a vaccine that induced antibodies that bind to oxycodone and evaluated the efficacy of this active vaccine (Oxy-TT) versus the carrier protein tetanus toxoid (TT). Our primary goal was to examine the intravenous self-administration of oxycodone in the rats.

This reorganization of Figure 2 from the paper depicts one of the key findings. The right panel shows the average number of infusions of oxycodone (0.06 mg/kg/infusion) obtained by subgroups of the Oxy-TT and TT rats. This median split analysis divides the Upper from Lower halves of the distribution based on average oxycodone responding across the 18 session acquisition interval. The distribution for the Oxy-TT group was more bimodal compared with the TT control group, indicating that some Oxy-TT rats took very little oxycodone across the acquisition period and some self-administered more. We defined successful acquisition as an average of 7 or more infusions obtained across two sequential days and the left panel reflects the proportion of the entire distributions of TT versus Oxy-TT that met this standard. Combined, we can infer that about 40% of the Oxy-TT animals essentially failed to acquire stable self-administration behavioral whereas all of the TT group did under these conditions. While it may seem disappointing to some eyes that the vaccine “worked” to prevent the establishment of stable self-administration in only 40% of the animals, this needs to be viewed in the context of human substance abuse. Only minorities of the individuals who try a given drug will go on to develop a habitual use pattern. This can be observed (cross-sectionally) in the Monitoring the Future data [vol 1 adolescents; vol 2 adults], in Schramm-Sapyta et al 2009 and in Anthony et al, 1994. The best way to reduce harm from repetitive use problems with drugs is to prevent it from progressing to this stage in the first place. Our study shows that the Oxy-TT vaccine is potentially capable of protecting a substantial subset of those individuals who sample a drug enough to become habitual users.

These panels from Figure 5 of the paper show that there was basic biological efficacy of the vaccine. These data show the plasma (left panel) and brain (right panel) amounts of oxycodone in the two vaccine groups after administration of 1.0 or 2.0 mg/kg subcutaneously. This shows that considerably more oxycodone is in the plasma of the Oxy-TT groups (as is expected since the antibodies should retain drug in the bloodstream and not let it get into other tissues. Lesser amounts of oxycodone were in the brains of the Oxy-TT group as well which is again consistent with the anticipated effects of successful anti-drug vaccination.

The second major behavioral finding is a bit more subtle. As you can see from the first figure, above, the Oxy-TT rats that did acquire self-administration responded for more drug than did the TT control animals. This is consistent with the second figure, i.e., that less of each infusion of drug was reaching the brain. Thus, assuming the rats on average seek the same approximate amount of drug in their brain, the vaccine resulted in an increase in self-administration behavior. In order to probe the extent to which the rats prefer to self-administer oxycodone we increased the workload. In training the rats only had to make one lever response for each infusion of drug, known as a Fixed Ratio 1 (FR1) contingency. But the Progressive Ratio procedure makes each successive infusion within the daily session cost more. When we did that, the Oxy-TT animals decreased their intake to a greater extent than did the TT rats. This figure is from a second cohort of rat groups that were trained to self-administer a

higher per-infusion dose (0.15 mg/kg/inf) of oxycodone. Under these conditions the Lower half of the Oxy-TT group self-administered about the same amount of drug as the entire TT group and the Upper half self-administered more. The figure depicts mean intake, post-acquisition, in four different workload conditions, starting and ending with the FR1 training condition. The two middle bars depict the oxycodone intake under two PR schedules which differ in steepness of the incrementing workload. There was a change for the TT group only in the hardest PR condition but this did not reach statistical significance. In contrast the overall number of infusions in a session that were obtained by the Oxy-TT animals (this is for the entire group) were reduced when it took more responses to obtain successive infusions. This shows that despite self-administering slightly more oxycodone when it is easy to get (FR1), the Oxy-TT animals are more likely to reduce their intake when the conditions are made slightly more difficult. Making drugs more difficult to obtain is, of course, one of the population level strategies we use to combat drug addiction. This is reflected in taxes and the regulation of sales of alcohol and tobacco that have been proven to reduce problematic use of these legal substances. Parents routinely use different strategies to make it more difficult for their teenagers to access drugs of all types. Many therapeutic interventions for drug abusers involve lifestyle changes that make getting access to drug more laborious. Thus, a strategy that makes an individual more liable to reduce their drug use when the costs increase has the potential for success in reducing drug use harms.

This last finding also has important implications for the design of human clinical trials that attempt to test the efficacy of anti-drug vaccines. The default approach has been to use measures of drug use as the measure of “success” of the trial. These data suggest that vaccinated people could use the same or even slightly more drug and still be getting a protective effect. That is, they might become more susceptible to other interventions which, for example, raise the cost or effort of getting drug.

__

*authors contributed equally

Funding for this work provided by USPHS Grants R01 DA035281, R01 DA024705, UH3 DA041146 (K.D.J.) and F32 AI126628 (C.S.W.).

Advertisements

March 19, 2017

Vaccination against methamphetamine works in female rats

Filed under: Methamphetamine, Vaccines, Vape inhalation, Vapor Inhalation — mtaffe @ 9:32 am

We have shown that a vaccine designed to blunt the effects of methamphetamine works in male rats in two prior publications, summarized here and here. We have also had success showing that vaccines directed against the synthetic cathinones MDPV (“bathsalts”) and alpha-PVP (“flakka”) work to reduce the effects of those drugs. A brief video outlining the approach to generating vaccines that might be helpful for drug abused created by NIDA can be found here.

The following has recently been accepted for publication:

Nguyen, J.D., Bremer, P.T., Hwang, C.S., Vandewater, S.A., Collins, K.C., Creehan, K.M., Janda, K.D. and Taffe, M.A. Effective active vaccination against methamphetamine in female rats, Drug Alcohol Depend, 2017, 175:179-186. [Publisher Site] [PubMed]

In this study we show that an increase in the amount that female rats move around their cages after an injection of methamphetamine is reduced in the MH6-KLH vaccinated rats.

As you can see in the explainer video, the main principle of anti-drug vaccination is that antibodies can bind some of the drug molecules (methamphetamine in this case) in the bloodstream, thereby preventing them from getting into the brain. This capacity to retain methamphetamine is relatively fixed at a given point in the vaccine sequence, thus administering a sufficiently high dose can (should) overcome the protection.

In our data, the effects of the vaccine were dose dependent. This is Figure 4 from the paper which depicts locomotor activity rates (counts per minute) in the MH6-KLH and KLH groups in the first and second hours after injection of methamphetamine in three doses [Significant differences from the Vehicle and 0.25 mg/kg within Group and Hour are indicated by §, from Vehicle (only) by # and from the 0.5 mg/kg condition by &. ]. There is a dose-dependent increase in activity rate compared with the vehicle injection condition. With respect to the active vaccination group, complete protection was found at the 0.25 mg/kg dose and partial protection at 0.5 mg/kg compared with the KLH group; the two groups were about the same after 1.0 mg/kg was injected. This further enhances our ability to interpret these data as a specific effect of the vaccination and to determine where the threshold for effective protection may lie.

There was another finding in this study which was slightly disappointing in terms of the vaccine study but greatly enhanced our understanding of another thing that we have been working on, namely vapor inhalation techniques to deliver drugs to rats for various research purposes. Most specifically we showed that e-cigarette type vapor inhalation of methamphetamine (and MDPV and mephedrone) increases the activity of male rats to a similar extent as it does when injected (blogpost overview). We used this model in the present study as well and confirmed that just as with male rats, the female rats activity in the cage was increased after vapor inhalation of methamphetamine to about the same extent as after the injected doses. Therefore up to this point in time we were assuming that the dose delivered to the rat was approximately similar when similar behavioral results were produced.

Unfortunately there was no difference in the effects of inhaled methamphetamine across the vaccinated and control groups of rats. We originally interpreted this as potentially a difference in the rate of drug penetration into the brain which minimized the ability of the vaccine-generated antibodies to prevent locomotor effects.

Upon reviewer request we then examined the blood levels of methamphetamine after injection (0.25, 1.0 mg/kg, i.p.) and the inhalation condition in a different group of unvaccinated female rats. We found that methamphetamine was about ten times higher in the blood after inhalation versus injection in this new study. This of course explains why the vaccinated group was not protected, i.e., the dose under inhalation was far past the ability of the antibodies to sequester in the bloodstream.

The curious thing is still why a similar level of locomotor activity was produced at the 10-fold difference in methamphetamine levels. Very likely this is due to the rate at which drug is delivered to the animal- in our inhalation model this takes place over 30 minutes whereas an injection takes seconds. Obviously one of our next avenues of research is to better determine the way that drug levels increase in the blood during vapor inhalation.

December 9, 2016

Vaccination against the effects of MDPV (“bathsalts”) and alpha-PVP (“flakka”)

Filed under: alpha-PVP, Cathinones, MDPV, Vaccines — mtaffe @ 10:10 am

The substituted cathinone stimulants 3,4-methylenedioxypyrovalerone (MDPV) and alpha-pyrrolidinopentiophenone(alpha-PVP) have emerged as significant public health concerns in recent years. These drugs turned out to be monoamine transporter inhibitors with high selectivity for the dopamine transporter. These two compounds lack the monoamine releasing properties of methamphetamine, MDMA and other recently popular cathinone derivatives such as mephedrone and methylone. As we’ve shown, both MDPV and alpha-PVP are highly reinforcing in the rat self-administration paradigm and increase locomotor behavior when injected non-contingently or inhaled with e-cig technology. Although these drugs are still in the early stages of market penetration, the data from our lab as well as several other labs suggest that these will have high abuse liability. Effective countermeasures are therefore likely to be needed in the future.

One method to counteract effects of psychoactive drugs that has been attempted is vaccination; an explainer video from NIDA is available here. In this strategy a drug-like chemical structure is attached to a large protein that generates an immune response. When successful, this immune response creates antibodies that circulate in the blood with the capacity to recognize and bind to the target drug molecule. If this is done to effective levels, the administration of a given dose of drug leads to a reduced response, due to part of the drug dose being bound to antibodies in the bloodstream which prevents from entering the brain.

A paper describing an initial effort to develop a vaccine to provide protection against the effects of MDPV and alpha-PVP has recently been accepted for publication. As with all of our vaccine work to date, this was conducted in collaboration with the Janda laboratory at TSRI.

Nguyen, J.D., Bremer, P.T., Ducime, Creehan, K.M., Kisby, B.R., Taffe, M.A. and Janda, K.D. Active vaccination attenuates the psychostimulant effects of α-PVP and MDPV in rats, Neuropharmacology, 2017, 116:1-8. [PubMed][Publisher Site]

In this study, Paul Bremer and Alex Ducime created vaccine candidates designed to generate antibodies against MDPV and alpha-PVP, respectively. Initially, three groups of male rats were vaccinated to evaluate the MDPV-specific, alpha-PVP-specific vaccines against a group vaccinated with the immunogenic protein (keyhole limpet hemocyanin; KLH). The antibodies in the MDPV-vaccinated group showed high affinity for MDPV but not for alpha-PVP or methamphetamine. Likewise, the antibodies in the alpha-PVP group were selective for alpha-PVP over MDPV or methampetamine.

Brent Kisby, an undergraduate on an extended internship, in combination with Kevin Creehan and Jacques Nguyen first determined if these rats would exhibit functional protection against drug exposure. We selected a wheel-activity response to drug injection (see Huang et al, 2012) because this had proved effective at screening anti-methamphetamine candidate vaccines in our prior study (Miller et al, 2013).
nguyen17-alphavaccfig3-wheel This figure (click to enlarge) shows wheel activity (quarter revolutions) in the four hours following injection with four doses of alpha-PVP (Panels A, B) or four doses of MDPV (Panels C, D). The left hand panels depict the effects of drug in the KLH-only control groups while the right hand panels depict the effects of drug in the respective alpha-PVP-KLH and MDPV-KLH vaccine groups. The asterix indicates a significant change of activity relative to the vehicle (saline) injection condition. The takeaway message here is that doses of alpha-PVP (0.5, 1.0 mg/kg, i.p.) and MDPV (1.0 mg/kg, i.p.) which increase wheel activity in the control group do not do so in the respective vaccine group. The vaccine can be partially surmounted since the 5 mg/kg dose of each drug increased activity in the vaccinated rats, although this increase was numerically lower and lasted less long in the MDPV-KLH and alpha-PVP-KLH animals compared with the control group.

This promising result led to the design of an intravenous self-administration study to test the ability of alpha-PVP-KLH vaccination to alter the course of self-administration. Jacques Nguyen and Kevin Creehan headed up this study.
A group of rats were first trained to self-administer alpha-PVP, prior to any vaccination. This is only the second study to publish the acquisition of alpha-PVP self-administration in an animal model (see Aarde et al, 2015) and we found that a 0.1 mg/kg/infusion dose was required to produce good acquisition in Sprague-Dawley male rats. Thereafter the rats were placed on hiatus from drug self-administration and given a 5 week protocol of three immunizations, divided into two groups- one receiving KLH only and the other receiving alpha-PVP-KLH vaccine. We showed first that on return to self-administration at a reduced per-infusion dose of 0.025 mg/kg/infusion the alpha-PVP-KLH vaccinated animals self-administered more drug. This result is consistent with the circulating antibodies producing partial reduction of the dose as it was self-administered and the corresponding behavioral compensation to produce similar brain levels of drug.
nguyen17-fig7-prepostAfter three weeks the animals were given a booster immunization which resulted in about a doubling of the circulating antibody level (titer). This resulted in no change in the KLH-only animals’ drug intake, however the alpha-PVP-KLH animals changed from a mean of 17-20 infusions per session to a mean of about 4-5 infusions per session, a significant reduction in self administration. This lasted for 15 sessions and is depicted in the figure (click to enlarge) as Post4-Post8 bins of three sequential sessions.

As discussed in the paper this is an initial feasibility study but it shows the potential of the anti-drug immunotherapy strategy to be effective against the effects of both MDPV and alpha-PVP. This should encourage additional work to determine the extent and nature of the protection against these substituted cathinone stimulants that can be achieved with vaccines.

These studies were funded by USPHS grants DA024705, DA042211 and DA037709.
__
Additional Reading: A list of our cathinone-related publications can be found here.

June 7, 2015

Active vaccination against methamphetamine slows acquisition of self-administration

Filed under: Methamphetamine, Vaccines — mtaffe @ 7:01 pm

The following has been recently accepted for publication:

Miller, M.L., Aarde, S.M., Moreno, A.Y., Creehan, K.M., Janda, K.D. and Taffe, M.A Effects of active anti-methamphetamine vaccination on intravenous self-administration in rats. Drug Alcohol Depend, 2015, 153:29-36 [Publisher Site]

In this new paper we follow up on our first finding that a anti-methamphetamine conjugate vaccine (referred to as the MH6-KLH conjugate) changes locomotor activity and body temperature responses to methamphetamine [Miller et al, 2013; blog post]. The new study uses an intravenous self-administration paradigm in rats to determine if MH6-KLH vaccination is capable of altering voluntary dosing with methamphetamine. The rats are surgically implanted with indwelling venous catheters which may be attached to a micro-pump during testing sessions. Upon making a press on the drug-associated lever a small infusion of drug is delivered. Over successive (daily) testing sessions, if the amount of drug-associated lever pressing increases while responses on the other lever stay at low levels, this can be interpreted as the rats having learned that the drug is pleasurable. They also tend to express their satiety point in terms of relatively stable asymptotic levels of intake after about 10-15 sessions.

Figure1AThe main takeaway message from this study is that we are the first to show an attenuation of voluntary methamphetamine (MA) intake by means of active vaccination. In this figure, we show the percentage of rats in the MH6-KLH and KLH-only (control) groups who self-administered at least 11 infusions (0.1 mg/kg/inf) on two consecutive days. This acquisition criterion is arbitrary but using a cutoff of a few more or slightly fewer infusions makes little difference in the overall picture. In this case a survival analysis identified significantly delayed acquisition in the MH6-KLH vaccinated group. As we write in the paper

The delay in acquisition was substantial, with less than 17% of the vaccinated group reaching acquisition criteria after 7 sessions compared with 75% of controls. Furthermore, only 66% of the MH6-KLH-vaccinated rats compared with 100% of the controls reached acquisition criteria by 13 sessions of training.

Whether these findings reflect a real-world impact and significance, well, that is a matter of debate and additional investigation. Our position is that many people experience various psychoactive drugs and never go on to develop lasting addiction and/or liability for compulsive use. Some of these trajectories include the pattern of trying the drug once or a few times and deciding it doesn’t do much for the individual. The largest difference in the percent of animals opting not to take substantial amounts of MA in a daily session came after 7 chances. In our model, rats continue to be offered MA and indeed are given a priming injection if they haven’t made a response in 30 min. This was done to bias the study for complete population acquisition, at least in the control group. Real world users, of course, often make choices which prevent them from even having the opportunity to try MA again if they find it unpalatable after the first few exposures.

__
These studies are funded by NIH Grant R01 DA024705

December 20, 2012

Functional efficacy of an anti-methamphetamine vaccine

Filed under: Methamphetamine, Thermoregulation, Vaccines — mtaffe @ 9:31 am

An early study which attempted to generate active vaccination against methamphetamine (METH) found no significant differences between vaccinated and control rats in a locomotor response to METH (Byrnes-Blake et al. 2001), however the vaccine led to a monoclonal antibody which was effective as a passive vaccine in a range of pharmacological studies including pharmacokinetic, animal models of drug overdose, locomotor activity, self-administration, and drug discrimination (Byrnes-Blake et al. 2003; McMillan et al. 2002). Passive vaccines are considered to be less ideal because they require the infusion of large quantities of drug-specific antibodies which must be manufactured and stored for use. In many cases active vaccine can be manufactured more cheaply and the antibodies are then generated by the immune system. Typically, or perhaps ideally, the duration of protection for passive vaccination is not as long as with active vaccination. Thus there continues to be interest if determining if active vaccination can work.

Another group found that active vaccination with the same hapten published by Byrnes-Blake (2001), coupled to a “molecular adjuvant” with a tetanus toxin T-cell epitope in place of the traditional keyhole limpet hemocyanin (KLH), resulted in an intial increase in methamphetamine self-administration in rats, followed by a decrease to levels indistinguishable from controls over 15 sessions (Duryee et al. 2009). This enhances confidence that it would be possible to develop active vaccines against methamphetamine.

The following paper is now in press at Biological Psychiatry.

Miller ML, Moreno AY, Aarde SM, Creehan KM, Vandewater SA, Vaillancourt BD, Wright MJ Jr, Janda KD, Taffe MA. A Methamphetamine Vaccine Attenuates Methamphetamine-Induced Disruptions in Thermoregulation and Activity in Rats.Biol Psychiatry. 2012 Oct 22. pii: S0006-3223(12)00803-7. doi: 10.1016/j.biopsych.2012.09.010. [Epub ahead of print] [PubMed][DOI]

VaccineTelem-Fig2In this paper we have shown that active vaccination can protect against the effects of METH. This figure is reproduced from the paper and the data show that METH causes an elevation of body temperature and an increase in wheel activity in the control animals vaccinated with the carrier protein (KLH). These effects are blocked in the animals vaccinated with the MH6-KLH conjugate vaccine. These data show the potential for active vaccination to oppose effects of methamphetamine.

Another paper from a competing group (Shen et al, 2012) appeared at nearly the same time as ours, demonstrating efficacy of active vaccination against METH stimulated locomotor activity in mice. It is to be hoped that these three successful demonstrations of efficacy of anti-METH vaccines will overcome the apparent failure of the early Byrnes-Blake et al (2001) finding and stimulate additional research.

This project was supported by NIH/NIDA grant R01 DA024705.

A NIDA generated brief animation video on the basic idea of anti-drug vaccination can be found in this post.
__
Additional Reading:

Byrnes-Blake KA, Carroll FI, Abraham P, Owens SM. Generation of anti-(+)methamphetamine antibodies is not impeded by (+)methamphetamine administration during active immunization of rats. Int Immunopharmacol. 2001 Feb;1(2):329-38. [PubMed]

Duryee MJ, Bevins RA, Reichel CM, Murray JE, Dong Y, Thiele GM, Sanderson SD. Immune responses to methamphetamine by active immunization with peptide-based, molecular adjuvant-containing vaccines. Vaccine. 2009 May 14;27(22):2981-8. doi: 10.1016/j.vaccine.2009.02.105. Epub 2009 Mar 10. [PubMed]

Shen XY, Kosten TA, Lopez AY, Kinsey BM, Kosten TR, Orson FM. A vaccine against methamphetamine attenuates its behavioral effects in mice. Drug Alcohol Depend. 2012 Sep 27. doi: 10.1016/j.drugalcdep.2012.09.007. [Epub ahead of print] [PubMed]

Anti-drug vaccine explainer animation from NIDA

Filed under: Cocaine, Opiates, Vaccines — mtaffe @ 8:58 am

There’s also a writeup of the Koob/Janda/Crystal collaboration to generate an anti-cocaine vaccine with adenovirus carrier protein and the Koob/Janda work on heroin vaccine.

___
Wee, S., et al. Novel cocaine vaccine linked to a disrupted adenovirus gene transfer vector blocks cocaine psychostimulant and reinforcing effects. Neuropsychopharmacology [Epub ahead of print September 14, 2011]. PubMed

Stowe, G.N. et al., A vaccine strategy that induces protective immunity against heroin. Journal of Medicinal Chemistry 54(14), 5195–204, 2011. PubMed

Create a free website or blog at WordPress.com.