Elevated Neutrophil to Lymphocyte Ratio in Older Adults with Cocaine Use Disorder as a Marker of Chronic Inflammation

Methamphetamine Use Disorder and Inflammation: A Case-Control Study

OBJECTIVE

Methamphetamine use disorder (MUD) is a global health condition that impairs a person's health which may result in morbidity and mortality. Inflammation is a crucial process playing a vital role in MUD. For this reason, it is necessary to examine biochemical parameters for follow-up and treatment alternatives.

METHODS

We aimed to reveal the relationship between inflammatory response and MUD by evaluating peripheral hemogram parameters, leukocyte count, subtypes, and their ratios to each other, systemic immune inflammation index (SII), monocyte/high-density lipoprotein (HDL) ratio, and human C-reactive protein (CRP) in adult men with MUD. We included 76 adult male participants in the patient group and 70 adult male participants in the control group. We calculated the neutrophil/lymphocyte rate (NLR), monocyte/lymphocyte rate (MLR), platelet/lymphocyte rate (PLR), and basophil/lymphocyte rate (BLR). In addition, we obtained the SII and the monocyte/HDL rate.

RESULTS

The patients' leukocyte (p<0.001), platelet (p<0.001), plateletcrit (PCT) (p=0.002), neutrophil (p<0.001), monocyte (p=0.002), CRP (p<0.001), NLR (p=0.001), PLR (p=0.004), MLR (p=0.009), SII (p<0.001) and monocyte/HDL ratio (p<0.001) were higher than the control group. We observed a significant and positive relationship between the daily methamphetamine intake, and methamphetamine use duration (p=0.002), PCT (p=0.044), neutrophil (p=0.021), NLR (p=0.001), PLR (p=0.004), MLR (p=0.029), and SII (p<0.001). Daily methamphetamine intake had a significant and positive effect on SII. A one-unit increase in daily methamphetamine intake elevated SII by 165.53 units.

CONCLUSION

The results confirm the presence of peripheral subclinical inflammation and systemic immune inflammation in adult men with MUD.

Cocaine-use disorder and childhood maltreatment are associated with the activation of neutrophils and increased inflammation

BACKGROUND

Cocaine-use disorder (CUD) has been associated with early life adversity and activated cellular immune responses. Women are most vulnerable to complications from chronic substance disorders, generally presenting an intense feeling of abstinence and consuming significant drug amounts. Here, we investigated neutrophil functional activities in CUD, including the formation of neutrophil extracellular traps (NETs) and related intracellular signalling. We also investigated the role of early life stress in inflammatory profiles.

METHODS

Blood samples, clinical data, and history of childhood abuse or neglect were collected at the onset of detoxification treatment of 41 female individuals with CUD and 31 healthy controls (HCs). Plasma cytokines, neutrophil phagocytosis, NETs, intracellular reactive oxygen species (ROS) generation, and phosphorylated protein kinase B (Akt) and mitogen-activated protein kinases (MAPK)s were assessed by flow cytometry.

RESULTS

CUD subjects had higher scores of childhood trauma than controls. Increased plasma cytokines (TNF-α, IL-1β, IL-6, IL-8, IL-12, and IL-10), neutrophil phagocytosis, and production of NETs were reported in CUD subjects as compared to HC. Neutrophils of CUD subjects also produced high levels of intracellular ROS and had more activated Akt and MAPKs (p38/ERK), which are essential signalling pathways involved in cell survival and NETs production. Childhood trauma scores were significantly associated with neutrophil activation and peripheral inflammation.

CONCLUSION

Our study reinforces that smoked cocaine and early life stress activate neutrophils in an inflammatory environment.

Lymphocyte-related ratios, systemic immune-inflammatory and systemic inflammatory response index in alcohol use disorder

Addictive disorders are associated with systemic and central nervous system inflammation, which may be important for the onset and development of these diseases. Although lymphocyte-related parameters have recently been studied in alcohol use disorder (AUD), systemic immune-inflammation index (SII) and systemic inflammatory response index (SIRI) haven't. Lymphocyte-related ratios, SII and SIRI levels were evaluated between AUD and healthy controls (HC) in this study. It was a retrospective and cross-sectional study. This study included 72 patients with AUD and 184 individuals in the HC group. Lymphocyte related ratios such as neutrophil to lymphocyte ratio (NLR), monocyte to lymphocyte ratio (MLR) and platelet to lymphocyte ratio (PLR), SII and SIRI values were compared. Compared to HC group, NLR (p < 0.001), MLR (p < 0.001), and SIRI (p < 0.001) levels were significantly higher in AUD group. There was also a significant relationship between NLR and AST/ALT ratio in the AUD group (p = 0.022). The results of this study support that AUD is a chronic inflammatory psychiatric disorder. In addition, it may be useful to evaluate these markers in relation to liver enzymes in patients with AUD, as alcohol consumption causes liver damage. These markers may also be used in future studies to assess treatment response and disease severity.

Oxidative Stress and Inflammatory Biomarkers in People with Methamphetamine Use Disorder

Objective

This study aimed to investigate the blood serum levels of biomarkers specifying oxidative stress status and systemic inflammation between people using methamphetamine (METH) and the control group (CG). Serum thiol/disulfide balance and ischemia-modified albumin levels were studied to determine oxidative stress, and serum interleukin-6 (IL-6) levels and complete blood count (CBC) were to assess inflammation.

Methods

Fifty patients with METH use disorder (MUD) and 36 CG participants were included in the study. Two tubes of venous blood samples were taken to measure oxidative stress, serum thiol/disulfide balance, ischemia-modified albumin, and IL-6 levels between groups. The correlation of parameters measuring oxidative stress and inflammation between groups with sociodemographic data was investigated.

Results

In this study, serum total thiol, free thiol levels, disulfide/native thiol percentage ratios, and serum ischemia- modified albumin levels of the patients were statistically significantly higher than the healthy controls. No difference was observed between the groups in serum disulfide levels and serum IL-6 levels. Considering the regression analysis, only the duration of substance use was a statistically significant factor in explaining serum IL-6 levels. The parameters showing inflammation in the CBC were significantly higher in the patients than in the CG.

Conclusion

CBC can be used to evaluate systemic inflammation in patients with MUD. Parameters measuring thiol/disulfide homeostasis and ischemia-modified albumin can be, also, used to assess oxidative stress.

Toll-like receptor 4 antagonists reduce cocaine-primed reinstatement of drug seeking

RATIONALE

Cocaine can increase inflammatory neuroimmune markers, including chemokines and cytokines characteristic of innate inflammatory responding. Prior work indicates that the Toll-like receptor 4 (TLR4) initiates this response, and administration of TLR4 antagonists provides mixed evidence that TLR4 contributes to cocaine reward and reinforcement.

OBJECTIVE

These studies utilize (+)-naltrexone, the TLR4 antagonist, and mu-opioid inactive enantiomer to examine the role of TLR4 on cocaine self-administration and cocaine seeking in rats.

METHODS

(+)-Naltrexone was continuously administered via an osmotic mini-pump during the acquisition or maintenance of cocaine self-administration. The motivation to acquire cocaine was assessed using a progressive ratio schedule following either continuous and acute (+)-naltrexone administration. The effects of (+)-naltrexone on cocaine seeking were assessed using both a cue craving model and a drug-primed reinstatement model. The highly selective TLR4 antagonist, lipopolysaccharide from Rhodobacter sphaeroides (LPS-Rs), was administered into the nucleus accumbens to determine the effectiveness of TLR4 blockade on cocaine-primed reinstatement.

RESULTS

(+)-Naltrexone administration did not alter the acquisition or maintenance of cocaine self-administration. Similarly, (+)-naltrexone was ineffective at altering the progressive ratio responding. Continuous administration of (+)-naltrexone during forced abstinence did not impact cued cocaine seeking. Acute systemic administration of (+)-naltrexone dose-dependently decreased cocaine-primed reinstatement of previously extinguished cocaine seeking, and administration of LPS-Rs into the nucleus accumbens shell also reduced cocaine-primed reinstatement of cocaine seeking.

DISCUSSION

These results complement previous studies suggesting that the TLR4 plays a role in cocaine-primed reinstatement of cocaine seeking, but may have a more limited role in cocaine reinforcement.

Substance Use Disorders in the Geriatric Population: a Review and Synthesis of the Literature of a Growing Problem in a Growing Population

Purpose of review

Substance use disorders are becoming increasingly prevalent in the geriatric population, necessitating an updated understanding of the existing literature. This review aims to describe the epidemiology, special considerations, and management of substance use disorders in older adults.

Recent findings

PubMed, Ovid MEDLINE, and PsychINFO databases were searched from their inception through June 2022 using the following keywords: "substance use disorder," "substance abuse," "abuse," "illicit substances," "illicit drugs," "addiction," "geriatric," "elderly," "older adults," "alcohol," "marijuana," "cannabis," "cocaine," "heroin," "opioid," and "benzodiazepine." Our findings suggest an increasing trend in substance use in older adults despite medical and psychiatric consequences when using such substances. The majority of older patients admitted to substance abuse treatment programs were not referred by healthcare providers, suggesting room for improvement in the screening and discussion of substance use disorders. Our review also suggests that there should be careful consideration of COVID-19 and racial disparities when screening, diagnosing, and treating substance use disorders in the older population.

Summary

This review provides updated information on epidemiology, special considerations, and management of substance use disorders in older adults. As substance use disorders become more prevalent in older adults, primary care physicians must be prepared to recognize and diagnose substance use disorders as well as collaborate with and refer patients to geriatric medicine, geriatric psychiatry, and addiction medicine.

Substance use and medical outcomes in those age 50 and older involving cocaine and metamfetamine reported to United States poison centers

CONTEXT

Cocaine and metamfetamine use and overdose deaths among United States adults have been increasing in recent years. We examined associations of medical outcomes with co-used opioids and other substances among cocaine, and metamfetamine exposures in people age ≥50 years (N = 9300) reported to the National Poison Data System, 2015-2021.

METHODS

We first described increases in these exposures over time. We fitted generalized linear models for a Poisson distribution with a log link, one for cocaine exposures and the other for metamfetamine exposures, to examine associations of medical outcomes (major effects/death versus all others) with co-used other substances, controlling for exposure year and demographics.

RESULTS

The number of exposures increased steadily during the seven years, but metamfetamine exposures increased more rapidly starting in 2018. One-fifth of cocaine and one-sixth of metamfetamine exposures suffered major effects/death. Co-use of prescription opioids (incident risk ratio = 2.00, 95% CI = 1.76-2.28 for cocaine; incident risk ratio = 1.62, 95% CI = 1.27-2.07 for metamfetamine), illicit fentanyl (incident risk ratio =1.88, 95% CI = 1.08-3.27 for cocaine; incident risk ratio = 2.05, 95% CI = 1.04-4.06 for metamfetamine), heroin (incident risk ratio =1.62, 95% CI = 1.37-1.90 for cocaine), or amfetamine (incident risk ratio =1.73, 95% CI = 1.28-2.33 for cocaine) was associated with a higher likelihood of major effects/death.

DISCUSSION

Increases in the number of cocaine and metamfetamine exposures among older adults reported to poison centers are of concern, and so is the increased risk of major effects/death from polysubstance use, especially prescription and illicit opioids, among these illicit psychostimulant users.

CONCLUSIONS

Healthcare provider screening of individuals at risk of cocaine and/or metamfetamine use and psychoeducation about the dangers of these substance use are needed.

Role of the gut-brain axis in HIV and drug abuse-mediated neuroinflammation

Drug abuse and related disorders are a global public health crisis affecting millions, but to date, limited treatment options are available. Abused drugs include but are not limited to opioids, cocaine, nicotine, methamphetamine, and alcohol. Drug abuse and human immunodeficiency virus-1/acquired immune deficiency syndrome (HIV-1/AIDS) are inextricably linked. Extensive research has been done to understand the effect of prolonged drug use on neuronal signaling networks and gut microbiota. Recently, there has been rising interest in exploring the interactions between the central nervous system and the gut microbiome. This review summarizes the existing research that points toward the potential role of the gut microbiome in the pathogenesis of HIV-1-linked drug abuse and subsequent neuroinflammation and neurodegenerative disorders. Preclinical data about gut dysbiosis as a consequence of drug abuse in the context of HIV-1 has been discussed in detail, along with its implications in various neurodegenerative disorders. Understanding this interplay will help elucidate the etiology and progression of drug abuse-induced neurodegenerative disorders. This will consequently be beneficial in developing possible interventions and therapeutic options for these drug abuse-related disorders.

Within subject cross-tissue analyzes of epigenetic clocks in substance use disorder postmortem brain and blood

There is a possible accelerated biological aging in patients with substance use disorders (SUD). The evaluation of epigenetic clocks, which are accurate estimators of biological aging based on DNA methylation changes, has been limited to blood tissue in patients with SUD. Consequently, the impact of biological aging in the brain of individuals with SUD remains unknown. In this study, we evaluated multiple epigenetic clocks (DNAmAge, DNAmAgeHannum, DNAmAgeSkinBlood, DNAmPhenoAge, DNAmGrimAge, and DNAmTL) in individuals with SUD (n = 42), including alcohol (n = 10), opioid (n = 19), and stimulant use disorder (n = 13), and controls (n = 10) in postmortem brain (prefrontal cortex) and blood tissue obtained from the same individuals. We found a higher DNAmPhenoAge (β = 0.191, p-value = 0.0104) and a nominally lower DNAmTL (β = -0.149, p-value = 0.0603) in blood from individuals with SUD compared to controls. SUD subgroup analysis showed a nominally lower brain DNAmTL in subjects with alcohol use disorder, compared to stimulant use disorder and controls (β = 0.0150, p-value = 0.087). Cross-tissue analyzes indicated a lower blood DNAmTL and a higher blood DNAmAge compared to their respective brain values in the SUD group. This study highlights the relevance of tissue specificity in biological aging studies and suggests that peripheral measures of epigenetic clocks in SUD may depend on the specific type of drug used.

Neutrophil-to-Lymphocyte Ratio Can Distinguish Patients with Liver Cirrhosis from Healthy People but Cannot Distinguish Patients with Cirrhotic Hepatocellular Carcinoma from Patients with Liver Cirrhosis

PURPOSE

Identifying cirrhotic hepatocellular carcinoma (HCC) during liver cirrhosis (LC) stage is pivotal for improving the clinical outcomes of cirrhotic HCC patients. Inflammation-driven markers play a crucial role in tumorigenesis and tumor progression. Neutrophil-to-lymphocyte ratio (NLR) is an inflammatory response marker. This study aimed to evaluate the ability of NLR to distinguish cirrhotic HCC from LC.

METHODS

Data of healthy control (HC) people, LC patients, cirrhotic HCC patients, and non-cirrhotic HCC patients were retrospectively analyzed. Mann-Whitney U test and Chi-squared test were used to compare demographic and clinical parameters in different groups. Spearman correlation analysis was used to assess correlations. Receiver operating characteristic (ROC) curves were performed to determine diagnostic accuracy.

RESULTS

A total of 419 participants were enrolled in this study, including 152 HC people, 131 LC patients, 96 cirrhotic HCC patients, and 40 non-cirrhotic HCC patients. Level of NLR was elevated significantly in LC compared with HC (P < 0.001). No significant differences were found for NLR between LC and cirrhotic HCC (P = 0.083), as well as between cirrhotic HCC and non-cirrhotic HCC (P = 0.729). NLR was positively correlated with platelet-to-lymphocyte ratio (r = 0.33, P < 0.001). The area under the ROC curve (AUC) value for NLR to distinguish LC from HC was 0.759 (P < 0.001), and AUC value to distinguish cirrhotic HCC from LC was 0.567 (P = 0.083), and AUC value to distinguish non-cirrhotic HCC from cirrhotic HCC was 0.519 (0.415-0.623) (P = 0.729).

CONCLUSION

NLR can distinguish LC from HC but cannot not distinguish cirrhotic HCC from LC.

Ageing and older people who use illicit opioids, cocaine or methamphetamine: a scoping review and literature map

AIMS

To provide an overview of research literature on ageing and older people who use illicit opioids and stimulants by documenting the conceptual frameworks used and content areas that have been investigated.

METHODS

We conducted a scoping review of literature relating to ageing and older people who use illicit stimulants and opioids, defining 'older' as 40 years and above. Primary studies, secondary studies and editorials were included. Searches were conducted in PubMed and Embase in July 2020 and March 2021; the Cochrane library was searched in November 2021. Charted data included methodological details, any conceptual frameworks explicitly applied by authors and the content areas that were the focus of the publication. We developed a hierarchy of content areas and mapped this to provide a visual guide to the research area.

RESULTS

Of the 164 publications included in this review, only 16 explicitly applied a conceptual framework. Seven core content areas were identified, with most publications contributing to multiple content areas: acknowledgement of drug use among older people (n = 64), health status (n = 129), health services (n = 109), drug use practices and patterns (n = 84), social environments (n = 74), the criminal legal system (n = 28) and quality of life (n = 15).

CONCLUSIONS

The literature regarding older people who use illicit drugs remains under-theorized. Conceptual frameworks are rarely applied and few have been purposely adapted to this population. Health status and health services access and use are among the most frequently researched topics in this area.

The impact of medical insurance reimbursement on postoperative inflammation reaction in distinct cardiac surgery from a single center

Background

Evidences shows that socioeconomic status is reversely associated with the risk of morbidity and mortality for people with cardiovascular disease via pro-inflammation mechanism, but the population profile is not deeply defined on. We aimed to investigate the impact of medical insurance coverage on postoperative systemic inflammatory reaction in two kinds of disease populations undergoing distinct cardiac procedures.

Methods

A total of 515 patients receiving open mitral valve procedure with high-total expense from May 2013 through May 2021 in Sichuan Provincial People’s Hospital were retrospectively collected and stratified according to medical insurance reimbursement: low coverage with high out-pocket (< 30%), medium coverage (≤ 60%, but ≥ 30%), and high coverage (> 60%). Another 118 cases undergoing atrium septum defect (ASD) or patent foramen ovale (PFO) occlusion and taking on consistent low-total expense and low-coverage (< 30%) were also classified according to their insured conditions. The postoperative systemic inflammatory response indexes were high sensitivity C-reactive protein (hs-CRP) and the neutrophil–lymphocyte ratio (NLR).

Results

Low insurance reimbursement population undergoing open mitral valve procedure had a higher level of hs-CRP and NLR but not troponin I protein or lactate within 48 h postoperatively, and higher thoracic drainage, longer ventilation use and stay in intensive care unit. No significant difference in inflammatory indexes existed among diverse medical insurance coverage in population undergoing ASD/PFO occlusion.

Conclusions

Higher inflammatory reaction and weaker clinical recovery was associated with lower insurance coverage population undergoing open mitral valve procedure but not ASD/PFO interventional occlusion procedure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-07920-8.

U.S. older adults' heroin and psychostimulant use treatment admissions, 2012-2019: Sociodemographic and clinical characteristics

BACKGROUND

Increases in U.S. older adults' nonprescription opioid and psychostimulant use call for examining their treatment admissions for these substances.

METHODS

Using admissions age 55 + involving heroin (N = 299,073) from the 2012-2019 Treatment Episode Data Set-Admissions, we examined trends and sociodemographic and clinical characteristics of three groups: (1) heroin-only admissions (i.e., not involving cocaine or methamphetamine), (2) heroin-cocaine admissions, and (3) heroin-methamphetamine admissions. Bivariable and multivariable logistic regression analyses were conducted to examine the research questions.

RESULTS

Between 2012 and 2019, the numbers of both heroin-only and heroin-cocaine admissions increased 2.3-fold and heroin-methamphetamine admissions increased seven-fold. First time heroin-methamphetamine admissions increased 18-fold. Heroin-methamphetamine admissions were concentrated in the Western region and heroin-cocaine admissions in the Northeastern region. Multivariable analyses showed a nearly 6 times higher relative risk ratio (RRR; 95% CI=5.24-6.74) for heroin-methamphetamine vs. heroin-only admissions in 2019 compared to 2012. Being non-Hispanic Black, compared to non-Hispanic White, was associated with a RRR of 2.4 (95% CI=2.34-2.46) for heroin-cocaine admissions and a RRR of 0.14 (95% CI=0.12-0.15) for heroin-methamphetamine admissions. Late-onset heroin use, experience of homelessness and other psychiatric problems, and past 30-day arrest episodes were associated with a higher likelihood of heroin-cocaine and heroin-methamphetamine admissions, while injection drug use (IDU) was associated with a higher likelihood of heroin-methamphetamine admissions only.

CONCLUSIONS

Healthcare providers should assess and monitor psychostimulant, methamphetamine in particular, use among older adults. Those who use heroin and psychostimulants should receive substance use treatment and help to secure stable housing and meet other living needs.

Neutrophil-lymphocyte and Platelet-lymphocyte Ratios among Adolescents with Substance Use Disorder: A Preliminary Study

Objective

Substance use disorder (SUD) is a serious public health problem affecting both the individual and the society, and substance use-related deaths and disability have been shown to increase gradually. Recent etiologic studies have reported that there is a relation between inflammatory parameters and psychiatric disorders. The neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) used as an indicator of inflammation have been shown to be increased in various psychiatric disorders. In this study, we aimed to investigate the NLR and PLR in adolescents with SUD.

Methods

This study was conducted by retrospectively examining the records of 55 male adolescents who were followed up with SUD in a child and adolescent psychiatry outpatient clinic between November 2019−June 2020. Patients who had comorbid psychiatric disorder were included, and those who received any psychotropic medication were excluded. A total of 61 healthy male adolescents in the same age range without any psychiatric disorders were recruited as a control group. Neutrophil-lymphocyte-platelet counts were noted retrospectively from complete blood tests, and NLR-PLR were calculated.

Results

The NLR and PLR of adolescents with SUD were significantly higher than the healthy adolescents (p < 0.01, p < 0.01, respectively). In addition, conduct disorder, depression, and attention deficit/hyperactivity disorder, which were determined as the most common comorbid psychiatric disorders had no effects on NLR (p = 0.513, p = 0.584, p = 0.394, respectively) and PLR (p = 0.210, p = 0.346, p = 0.359, respectively).

Conclusion

The results of current study indicate that inflammatory processes may have a key role in the pathophysiology of SUD.

Combined score of C-reactive protein level and neutrophil-to-lymphocyte ratio: A novel marker in distinguishing children with exacerbated asthma

Background

Both C-reactive protein (CRP) level and neutrophil-to-lymphocyte ratio (NLR) are commonly elevated in patients with asthma. It is necessary to develop a novel marker, the combined score of CRP level and NLR (C-NLR score) based on cutoff points of CRP and NLR, and apply it in asthma diagnosis. The aim of this study was to explore whether C-NLR could distinguish children with exacerbated asthma.

Methods

Children suffering from exacerbated asthma were regarded as the asthmatic group (n = 86), which was divided into three groups: mild (n = 54), moderate (n = 17), and severe (n = 15). The control group consisted of children without any allergic disease and infection (n = 38). To compare CRP level and NLR between the asthmatic group and control group, a receiver-operating characteristic curve was constructed to determine area under the curve (AUC) and optimal cutoff point. Thereafter, the C-NLR score was classified as follows: C-NLR score of 2 with an elevated CRP level and high NLR, a C-NLR score of 1 with one of these abnormalities, and a C-NLR score of 0 with a normal CRP level and low NLR. The C-NLR score was then compared among different asthma groups.

Results

In the control group, the CRP level and NLR were 1.9 (0.5–2.6) mg/L and 1.01 (0.69–1.31), respectively. In the asthmatic group, the CRP level and NLR were 7.3 (3.2–14.2) mg/L and 3.08 (1.73–5.34), respectively, which were higher than those in the control group (p < 0.001 for CRP and p < 0.001 for NLR). The AUC of CRP was 0.86, and the optimal cutoff point was 3.6 mg/L. The AUC of NLR was 0.86, and the optimal cutoff point was 1.72. The AUC of the C-NLR score was 0.94, and the optimal cutoff point was 1.

Conclusions

C-NLR, a novel inflammatory marker, was applied here for the exacerbated asthma for the first time. Our study has shown C-NLR is a promising marker to distinguish children with exacerbated asthma from healthy children.

Challenges in Prescribing Clozapine in the Era of COVID-19: A Review Focused on Immunological Implications

The global COVID-19 pandemic has disrupted every aspect of the healthcare system. Apart from the issues surrounding COVID-19 itself, care for existing patients has met many challenges. One such challenge is caring for patients who are on clozapine treatment and have been confirmed positive for COVID-19. Schizophrenia has been considered to have a deep connection with the immune system, and clozapine can induce further changes in this system. COVID-19 can ravage the compromised immune system and aggravate tissue damage. The intricate relations between schizophrenia, clozapine, and COVID-19 make it difficult to predict the clinical course of COVID-19 in clozapine-treated patients. However, the rigid prohibition on using clozapine if COVID-19 is confirmed may harm patients. Patients who have to use clozapine are often refractory cases with no alternatives. Therefore, the decision to maintain or stop clozapine must be made after a comprehensive review of the patient’s unique situation. To do this, theoretical and practical issues surrounding the use of clozapine in COVID-19 should be reviewed and discussed. In this review, we gather useful information surrounding this issue and present an overview. Focusing on the immune system, various theoretical possibilities that could arise from schizophrenia, clozapine, and COVID-19 were carefully examined, and practical checklists for the care of these patients were explored. It is hoped that this review will convince many clinicians to pay attention to this momentous issue and facilitate more active sharing of clinical experiences.

A "Drug-Dependent" Immune System Can Compromise Protection against Infection: The Relationships between Psychostimulants and HIV

Psychostimulant use is a major comorbidity in people living with HIV, which was initially explained by them adopting risky behaviors that facilitate HIV transmission. However, the effects of drug use on the immune system might also influence this phenomenon. Psychostimulants act on peripheral immune cells even before they reach the central nervous system (CNS) and their effects on immunity are likely to influence HIV infection. Beyond their canonical activities, classic neurotransmitters and neuromodulators are expressed by peripheral immune cells (e.g., dopamine and enkephalins), which display immunomodulatory properties and could be influenced by psychostimulants. Immune receptors, like Toll-like receptors (TLRs) on microglia, are modulated by cocaine and amphetamine exposure. Since peripheral immunocytes also express TLRs, they may be similarly affected by psychostimulants. In this review, we will summarize how psychostimulants are currently thought to influence peripheral immunity, mainly focusing on catecholamines, enkephalins and TLR4, and shed light on how these drugs might affect HIV infection. We will try to shift from the classic CNS perspective and adopt a more holistic view, addressing the potential impact of psychostimulants on the peripheral immune system and how their systemic effects could influence HIV infection.

The Challenge by Multiple Environmental and Biological Factors Induce Inflammation in Aging: Their Role in the Promotion of Chronic Disease

The aging process is driven by multiple mechanisms that lead to changes in energy production, oxidative stress, homeostatic dysregulation and eventually to loss of functionality and increased disease susceptibility. Most aged individuals develop chronic low-grade inflammation, which is an important risk factor for morbidity, physical and cognitive impairment, frailty, and death. At any age, chronic inflammatory diseases are major causes of morbimortality, affecting up to 5-8% of the population of industrialized countries. Several environmental factors can play an important role for modifying the inflammatory state. Genetics accounts for only a small fraction of chronic-inflammatory diseases, whereas environmental factors appear to participate, either with a causative or a promotional role in 50% to 75% of patients. Several of those changes depend on epigenetic changes that will further modify the individual response to additional stimuli. The interaction between inflammation and the environment offers important insights on aging and health. These conditions, often depending on the individual's sex, appear to lead to decreased longevity and physical and cognitive decline. In addition to biological factors, the environment is also involved in the generation of psychological and social context leading to stress. Poor psychological environments and other sources of stress also result in increased inflammation. However, the mechanisms underlying the role of environmental and psychosocial factors and nutrition on the regulation of inflammation, and how the response elicited for those factors interact among them, are poorly understood. Whereas certain deleterious environmental factors result in the generation of oxidative stress driven by an increased production of reactive oxygen and nitrogen species, endoplasmic reticulum stress, and inflammation, other factors, including nutrition (polyunsaturated fatty acids) and behavioral factors (exercise) confer protection against inflammation, oxidative and endoplasmic reticulum stress, and thus ameliorate their deleterious effect. Here, we discuss processes and mechanisms of inflammation associated with environmental factors and behavior, their links to sex and gender, and their overall impact on aging.