Crystal methamphetamine initiation among street-involved youth

The gut microbiota contributes to methamphetamine-induced reproductive toxicity in male mice

Methamphetamine (METH) is a psychostimulant drug belonging to the amphetamine-type stimulant class, known to exert male reproductive toxicity. Recent studies suggest that METH can disrupt the gut microbiota. Furthermore, the gut-testis axis concept has gained attention due to the potential link between gut microbiome dysfunction and reproductive health. Nonetheless, the role of the gut microbiota in mediating the impact of METH on male reproductive toxicity remains unclear. In this study, we employed a mouse model exposed to escalating doses of METH to assess sperm quality, testicular pathology, and reproductive hormone levels. The fecal microbiota transplantation method was employed to investigate the effect of gut microbiota on male reproductive toxicity. Transcriptomic, metabolomic, and microbiological analyses were conducted to explore the damage mechanism to the male reproductive system caused by METH. We found that METH exposure led to hormonal disorders, decreased sperm quality, and changes in the gut microbiota and testicular metabolome in mice. Testicular RNA sequencing revealed enrichment of several Gene Ontology terms associated with reproductive processes, as well as PI3K-Akt signaling pathways. FMT conveyed similar reproductive damage from METH-treated mice to healthy recipient mice. The aforementioned findings suggest that the gut microbiota plays a substantial role in facilitating the reproductive toxicity caused by METH, thereby highlighting a prospective avenue for therapeutic intervention in the context of METH-induced infertility.

Prevalence and correlates of methamphetamine use in transitional age youth experiencing homelessness or housing instability in San Francisco, CA

INTRODUCTION

Substance use, including methamphetamine use, is a contributing factor in HIV acquisition and treatment. Stimulant use is linked to mental health yet there is limited data from youth in community-based settings.

DESIGN

One hundred marginally housed or homeless transitional age youth (TAY) were recruited at Larkin Street Youth Services and completed a survey on mental health and substance use.

METHODS

We conducted secondary data analysis using multivariable logistic regression models to identify the correlates of methamphetamine use among TAY.

RESULTS

The participants' mean age was 22. Of those who reported methamphetamine use in the past 3 months, 64% were Gay, Bisexual, or Pansexual. Factors independently associated with methamphetamine use were; living with HIV (adjusted odds ratio [aOR] = 3.18, 95% CI = 1.11-9.15), depressive symptoms (aOR = 6.02, 95% CI = 1.46-24.78), symptoms of PTSD (aOR = 13.38, 95% CI = 1.59-112.73), polysubstance use in the past 3 months (aOR = 50.02, 95% CI = 9.72-257.46) and a history of injection drug use (aOR = 8.38, 95% CI = 1.87-37.53).

CONCLUSIONS

Results from this study suggest a need to develop, adapt, and rapidly implement comprehensive interventions that address the combined epidemics of substance use, HIV, and mental health among TAY.

CLINICAL RELEVANCE

This article examines factors associated with methamphetamine use among transitional age youth (TAY) experiencing homelessness or housing instability. Several factors were associated with use, including depression, PTSD, HIV status, polysubstance use, and injection drug use. These findings highlight the need for nurses to assess for methamphetamine use among youth as well as associated mental health and physical health problems. Nurses should link TAY who are using methamphetamine to evidence-based treatment programs to address substance use and comorbid conditions.

Opioid agonist therapy engagement and crystal methamphetamine use: The impact of unregulated opioid use in Vancouver, Canada

BACKGROUND

Crystal methamphetamine use has substantially increased among people who use opioids in recent years, yet the impact of opioid agonist therapy (OAT) on crystal methamphetamine use remains poorly characterized. Therefore, we sought to examine the relationship between OAT engagement and crystal methamphetamine use and to assess if this relationship differs according to the ongoing use of unregulated opioids.

METHODS

Data was collected from two harmonized ongoing prospective cohorts of people who use drugs in Vancouver, Canada, between December 2005 and March 2020. We employed multivariable generalized estimating equations to study the relationship between OAT engagement and crystal meth use stratified by ongoing unregulated opioid use.

RESULTS

Of 1742 participants who reported frequent opioid use at baseline, the median age was 42 years, and 61.3% were male. Multivariable analyses showed that compared to those who had not received OAT for at least one year: in the absence of ongoing unregulated opioid use, individuals who recently discontinued (adjusted Odds Ratio [aOR] = 0.47, 95% CI = 0.27-0.79), newly initiated (aOR = 0.52, 95% CI = 0.31-0.89), or were retained on OAT (aOR = 0.48, 95% CI = 0.31-0.72) reported a lower frequency of crystal methamphetamine use; in the presence of ongoing unregulated opioid use, individuals who newly initiated OAT reported a greater crystal methamphetamine use frequency (aOR = 1.24, 95% CI = 1.02-1.51).

CONCLUSIONS

We demonstrated a differential relationship between OAT engagement and crystal methamphetamine use that was conditional on the ongoing use of unregulated opioids. Our findings highlight the complexity of OAT implementation and suggest that polysubstance use patterns should be an important consideration for care providers when devising comprehensive treatment strategies and prognosticating treatment effects.

Predictors of crystal methamphetamine use initiation or re-initiation among people receiving opioid agonist therapy: A prospective cohort study

BACKGROUND

In the context of the ongoing opioid crisis in the United States and Canada, opioid agonist therapy (OAT) is the first-line treatment for opioid use disorder. However, there is growing concern regarding the increasing methamphetamine use among those on OAT, as well as the impact of such use may have on OAT retention and outcomes. We sought to identify the predictors of crystal methamphetamine initiation or re-initiation among people on OAT, in order to facilitate the development of effective preventive strategies.

METHODS

We employed multivariable generalized estimating equations to identify the predictors of crystal methamphetamine use initiation or re-initiation among those who were on OAT within two prospective cohorts in Vancouver, Canada between 2005 and 2020.

RESULTS

Of the 1281 participants receiving OAT, the median age was 43 years, and 59.2 % were male at baseline. During study follow-up, 564 (44.0 %) initiated or re-initiated crystal methamphetamine use while receiving OAT. In a multivariable model, a higher crystal methamphetamine use initiation or re-initiation rate was positively associated with younger age, unstable housing, unprotected sex, history of crystal methamphetamine use, as well as recent cocaine, prescription opioid, and unregulated opioid use (all p < 0.05).

CONCLUSIONS

We identified high and increasing rates of crystal methamphetamine use initiation or re-initiation among our sample of people on OAT. Intervention strategies including housing program referral, sexual risk reduction, and integrated treatment approaches targeting polysubstance use are urgently needed to reduce the risks associated with methamphetamine use as well as the co-use of methamphetamine and opioids.

Methamphetamine Downregulates the Sperm-Specific Calcium Channels Involved in Sperm Motility in Rats

Calcium channels play essential roles in sperm motility. A family of sperm-specific cation channels including CatSper1-4 has been identified as voltage-dependent ion channels that act as sperm motility regulators. Methamphetamine is known to cause apoptosis in seminiferous tubules and affect sperm quality. This research was conducted to investigate the effects of methamphetamine on expression of the CatSper family and Mvh genes. Thirty-six adult Wistar rats were divided into four groups of nine rats each: the control and experimental groups 1, 2, and 3. The control group received no solvents or drugs, but experimental groups 1, 2, and 3 were daily given 0.2 mL of a solution by gavage that contained 0.5, 1, and 2 mg of methamphetamine, respectively, for 45 days. The rats were then anesthetized, and one testis removed from each rat was used in a reverse transcription-polymerase chain reaction (RT-PCR). Analysis of variance (ANOVA) and Tukey's posthoc test were used to analyze the data at the P < 0.05 significance level. Treatment with methamphetamine resulted in decreased testis and epididymis weights compared to the control rats. The results showed that the mRNA fold expression level of the CatSper family and Mvh genes decreased significantly in experimental groups compared to that in the control (P < 0.05). Methamphetamine decreased the expression levels of the CatSper and Mvh genes, and thus, it seemed that it can increase the probability of infertility through sperm motility reduction by lowering the expression levels of these genes.

Homelessness and incarceration associated with relapse into stimulant and opioid use among youth who are street-involved in Vancouver, Canada

INTRODUCTION AND AIMS

While much research has sought to identify the factors associated with initiation and cessation of various forms of drug use among vulnerable youth, little is known about relapse into drug use in this population. We sought to characterise relapse into stimulant and opioid use among street-involved youth in Vancouver, Canada.

DESIGN AND METHODS

Data were collected between 2005 and 2017 from the At-Risk Youth Study, a prospective cohort study of street-involved youth who use illicit drugs in Vancouver. Multivariable extended Cox regression was utilised to identify factors associated with relapse into illegal stimulants and/or opioids among youth who had previously ceased using stimulants and/or opioids for 6 months or longer.

RESULTS

Among 246 participants who reported a period of cessation lasting 6 months or longer, 165 (67.1%) relapsed at some point during study follow-up. Youth who were recently incarcerated (adjusted hazard ratio [AHR]: 1.46), homeless (AHR: 1.43), or had a history of daily stimulant use (AHR: 1.48) were significantly more likely to report relapse, while youth of who identified as white (AHR: 0.74) were significantly less likely to report relapse (all P < 0.05).

DISCUSSION AND CONCLUSIONS

Relapse into stimulants and/or opioids was common among youth in our setting, and incarceration, homelessness, and daily stimulant use were found to be positively associated with relapse among youth. Findings suggest that increased access to youth housing supports and alternatives to the criminalisation of drug use may help to reduce the rates of relapse into stimulants and/or opioids in this population.

Longitudinal patterns of amphetamine use from adolescence to adulthood: A latent class analysis of a 20-year prospective study of Australians

BACKGROUND

To examine the longitudinal patterns of amphetamine use over twenty years from adolescence to the mid-thirties; and identify adolescent antecedents of future problematic patterns of use.

DESIGN

Ten-wave longitudinal study following participants from age 15 to age 35 in Victoria, Australia. Participants (N = 1755; 47% males) first enrolled in the Victoria Adolescent Health Cohort Study in 1992.

MEASUREMENTS

Outcome: Self-reported frequency of amphetamine use.

PREDICTORS

Gender, depression and anxiety, peer alcohol and tobacco use; self-reported alcohol, tobacco and cannabis use, self-reported adolescent antisocial behavior.

FINDINGS

Three different longitudinal patterns were identified: Non-user (83.7%); Occasional user (14.5%); Regular user (1.8%). Among the two user patterns, amphetamine use was commonly initiated in late teenage years or early 20s, peaked at mid-20s, and declined substantially by mid-30s. Participants who used cannabis and had smoking peers during adolescence were at significantly more likely to become an occasional or regular user (p <  .05).

CONCLUSION

Regular cannabis use and peer tobacco use during adolescence were the two strongest predictors of a longitudinal pattern of regular amphetamine use in the mid-30s. This suggests that prevention programs could be implemented around or before mid-adolescence and interventions to reduce amphetamine harms focus on high-risk individuals in their 20s when amphetamine use was at its peak.

Prolonged increase in ser31 tyrosine hydroxylase phosphorylation in substantia nigra following cessation of chronic methamphetamine

Methamphetamine (MA) exposure may increase the risk of motor or cognitive impairments similar to Parkinson's disease (PD) by middle age. Although damage to nigrostriatal or mesoaccumbens dopamine (DA) neurons may occur during or early after MA exposure, overt PD-like symptoms at a younger age may not manifest due to compensatory mechanisms to maintain DA neurotransmission. One possible compensatory mechanism is increased tyrosine hydroxylase (TH) phosphorylation. In the rodent PD 6-OHDA model, nigrostriatal lesion decreases TH protein in both striatum and substantia nigra (SN). However, DA loss in the SN is significantly less than that in the striatum. An increase in ser31 TH phosphorylation in the SN may increase TH activity in response to TH loss. To determine if similar compensatory mechanisms may be engaged in young mice after MA exposure, TH expression, phosphorylation, and DA tissue content were evaluated, along with dopamine transporter expression, 21 days after cessation of MA (24 mg/kg, daily, 14 days). DA tissue content was unaffected by the MA regimen in striatum, nucleus accumbens, SN, or ventral tegmental area (VTA), despite decreased TH protein in SN and VTA. In the SN, but not striatum, ser31 phosphorylation increased over 2-fold. This suggests that increased ser31 TH phosphorylation may be an inherent compensatory mechanism to attenuate DA loss against TH loss, similar to that in an established PD model. These results also indicate the somatodendritic compartments of DA neurons are more vulnerable to TH protein loss than terminal fields following MA exposure.

The Relative Influence of Injunctive and Descriptive Social Norms on Methamphetamine, Heroin, and Injection Drug Use Among Homeless Youths: The Impact of Different Referent Groups

The current study assessed the relative influence of both injunctive and descriptive norms in the context of different referent groups (i.e., family, street peers, home-based peers, and staff members) on past 30-day methamphetamine, heroin, and injection drug use behaviors of homeless youth. Cross-sectional data ( N = 911) were collected from three drop-in centers in Los Angeles, California. The study consisted of two parts: a social network interview and a computerized self-administered survey. Multivariate logistic regression models examined the association of objection to drug use from referent groups (injunctive norms; that is, street-based peers, home-based peers, relatives, staff members) and drug use of referent groups (descriptive norms) with youths’ substance use behaviors. Multivariate results indicated that the role of injunctive and descriptive norms varied across the three substance use behaviors and by referent group. Findings indicate the need to carefully consider the diversity of homeless youths’ networks in designing substance use interventions.

Violence, trauma and living with HIV: Longitudinal predictors of initiating crystal methamphetamine injection among sex workers

BACKGROUND

Despite rapid increases in crystal methamphetamine (CM) use worldwide and established gendered patterns of use, empirical research on CM injection initiation among sex workers is limited. Given the wide range of harms associated with CM, alongside stimulant effects including sexual dis-inhibition and prolonged awake-ness, this study aimed to longitudinally investigate socio-structural predictors of initiating CM injection among sex workers in Vancouver, Canada.

METHODS

Data (2010-2014) were drawn from a community-based cohort of women sex workers: AESHA (An Evaluation of Sex Workers Health Access). Participants completed bi-annual interviewer-administered questionnaires and HIV/STI testing. Kaplan Meier methods and Cox proportional hazards regression were used to model predictors of CM injection initiation among CM injection-naïve participants.

RESULTS

Of 455 participants eligible at baseline, 14.3% (n=65) injected CM for the first time over follow-up, with an incidence density of 6.79 per 100 person-years (95% Confidence Interval [CI] 5.30-8.69). In multivariable analysis, injection heroin use (Adjusted Hazard Ratio [AHR] 6.11; 95%CI 3.24-11.52), having an intimate partner who injects drugs (AHR 2.93; 95%CI 1.57-5.46), workplace violence (AHR 2.85; 95%CI 1.74-4.67), HIV seropositivity (AHR 2.69; 95%CI 1.45-5.00), and childhood abuse (AHR 1.86; 95%CI 0.99-3.49) were independently associated with initiating CM injection.

CONCLUSIONS

Findings underscore the gendered and social risk environment of CM injection initiation among sex workers. The strong influences of historical/workplace violence, coupled with heroin injection (known to be self-medicating for post-traumatic stress) as a primary risk pathway, emphasize the urgency of increasing access to integrated, trauma-informed addiction treatment and HIV care for marginalized women.

The relationship between violence and engagement in drug dealing and sex work among street-involved youth

OBJECTIVES

Street-involved youth are highly vulnerable to violence. While involvement in income-generating activities within illicit drug scenes is recognized as shaping youths' vulnerability to violence, the relative contributions of different income-generating activities remain understudied. We sought to examine the independent effects of drug dealing and sex work on experiencing violence among street-involved youth.

METHODS

Data were derived from a prospective cohort of street-involved youth aged 14-26 who used drugs in Vancouver, British Columbia, between September 2005 and May 2014. Multivariable generalized estimating equations were used to examine the impact of involvement in drug dealing and sex work on experiencing violence.

RESULTS

Among 1,152 participants, including 364 (31.6%) women, 740 (64.2%) reported having experienced violence at some point during the study period. In multivariable analysis, involvement in drug dealing but not sex work remained independently associated with experiencing violence among females (adjusted odds ratio [AOR]: 1.43; 95% confidence interval [CI]: 1.08-1.90) and males (AOR: 1.50; 95% CI: 1.25-1.80), while involvement in sex work only was not associated with violence among females (AOR: 1.15; 95% CI: 0.76-1.74) or males (AOR: 1.42; 95% CI: 0.81-2.48).

CONCLUSION

Findings indicate that involvement in drug dealing is a major factor associated with experiencing violence among our sample. In addition to conventional interventions, such as addiction treatment, novel approaches are needed to reduce the risk of violence for drug-using youth who are actively engaged in drug dealing. The potential for low-threshold employment and decriminalization of drug use to mitigate violence warrants further study.

Conducting Rapid Street Assessment of Drug Users in New York City Using Oral Fluid and Brief Interviews: A Feasibility Study

This study piloted the feasibility of rapidly collecting both self-reports of drug use and saliva specimens for drug toxicology in field settings. The use of oral fluid collection devices to supplement self-reports is unproven in street settings and may pose challenges for field research. Sixty adults who identified as recent illicit drug users were recruited in public settings in New York City and were asked to complete a brief drug screening inventory and provided saliva specimens. Descriptive findings are detailed along with critical best research practices and limitations that provide important directions for researchers looking to employ both toxicology and self-report in rapid field recruitment designs.