Association Between the Endocannabinoid System-Related Gene Variants and Epilepsy

The endocannabinoid system (ECS) is an intricate network consisting of receptors, enzymes, and endogenous ligands that play a pivotal role in various neurological processes. It has been implicated in the pathophysiology of several neurological disorders, including epilepsy. Extensive research has demonstrated the involvement of genetic factors in influencing the susceptibility to and progression of epilepsy. In this study, we focused on investigating the connection between genetic variations in genes related to the ECS and the occurrence of epilepsy. Some ECS-related gene variants were selected and genotyping was performed using the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) technique. Interestingly, CNR1 rs12720071 genotype (OR 16.33, 95% CI 1.8-149; p = 0.001) showed an association with generalized epilepsy and MGLL rs604300 genotype (OR 2, 95% CI 1.1-3.4; p = 0.013) demonstrated a relationship with females diagnosed with focal epilepsy. So, studying CNR1, MGLL, and their genetic variations provides insights into the role of the endocannabinoid system in health and diseases. Moreover, they hold the potential to pave the way for the development of novel therapeutic approaches specifically targeting them.

Biosensors, Recent Advances in Determination of BDNF and NfL

Key biomarkers such as Brain Derived Neurotrophic Factor (BDNF) and Neurofilament light chain (NfL) play important roles in the development and progression of many neurological diseases, including multiple sclerosis, Alzheimer's disease, and Parkinson's disease. In these clinical conditions, the underlying biomarker processes are markedly heterogeneous. In this context, robust biomarker discovery is of critical importance for screening, early detection, and monitoring of neurological diseases. The difficulty of directly identifying biochemical processes in the central nervous system (CNS) is challenging. In recent years, biomarkers of CNS inflammatory response have been identified in various body fluids such as blood, cerebrospinal fluid, and tears. Furthermore, biotechnology and nanotechnology have facilitated the development of biosensor platforms capable of real-time detection of multiple biomarkers in clinically relevant samples. Biosensing technology is approaching maturity and will be deployed in communities, at which point screening programs and personalized medicine will become a reality. In this multidisciplinary review, our goal is to highlight clinical and current technological advances in the development of multiplex-based solutions for effective diagnosis and monitoring of neuroinflammatory and neurodegenerative diseases. The trend in the detection if BDNF and NfL.

Sensitive electrochemical recognition of α-synuclein protein in human plasma samples using bioconjugated gold nanoparticles: An innovative immuno-platform to assist in the early stage identification of Parkinson's disease by biosensor technology

This research work explains the development of an electrochemical immunosensor for the selective recognition of SNCA in human biofluids. An innovative protocol was proposed for the green synthesis of gold nanoparticle-supported dimethylglyoxime (AuNPs@DMGO) using one-step electrogeneration method. Also, the application of AuNPs@DMGO for the sensitive quantification of α-Synuclein (SNCA) protein and its biomedical analysis. So, an innovative sandwich immunosensor was designed for the sensitive identification of SNCA antigen in an aqueous solution. The gold nanoparticles (AuNPs) were decorated on the surface of the glassy carbon electrode by chronoamperometry technique to provide appropriate immobilization surface with a large number of active sites for immobilization of specific biotinylated antibody (Ab1) and against SNCA protein. Then, the sandwich-type immuno-platform was completed by the attachment of secondary antibody (HRP conjugated Ab [Ab2]) to the primary complexes on the surface of the electrode. For the first time, α-Synuclein protein was measured with an acceptable linear range of 4-64 ng/mL and a lower limit of quantification of 4 ng/mL. Benefiting from the simplicity and high sensitivity, the proposed method shows a potential of employment in clinical applications and high-throughput screening of Parkinson's disease using POC.

Fatty acid amide hydrolase C385A polymorphism affects susceptibility to various diseases

The endocannabinoid (eCB) system is an important neuromodulatory system with its extensive network of receptors throughout the human body that has complex actions in the nervous system, immune system, and all of the body's other organs. Fatty acid amide hydrolase (FAAH) is an important membrane-bound homodimeric degrading enzyme that controls the biological activity of N-arachidonoylethanolamide (AEA) in the eCB system and other relevant bioactive lipids. It has been shown that several single nucleotide polymorphisms (SNPs) of FAAH are associated with various phenotypes and diseases including cardiovascular, endocrine, drug abuse, and neuropsychiatric disorders. A common functional and most studied polymorphism of this gene is C385A (rs324420), which results in the replacement of a conserved proline to threonine in the FAAH enzyme structure, leads to a reduction of the activity and expression of FAAH, compromises the inactivation of AEA and causes higher synaptic concentrations of AEA that can be associated with several various phenotypes. The focus of this review is on evidence-based studies on the associations of the FAAH C385A polymorphism and the various diseases or traits. Although there was variability in the results of these reports, the overall consensus is that the FAAH C385A genotype can affect susceptibility to some multifactorial disorders and can be considered a potential therapeutic target.

Synthesis, characterization, and application of gold nanostars for the identification of 2-Arachidonoyl glycerol

Background. The endocannabinoid system (ECS) is a complex of neurotransmitters in the central nervous system (CNS) and plays a key role in regulating cognitive and physiological processes. Also, 2-Arachidonoylglycerol (2-AG) is one of the imperative endocannabinoids with key roles in the CNS. It acts as a signaling lipid and activates the cannabinoid CB1 receptor. In addition, 2-AG is involved in a variety of physiological functions such as energy balance, emotion, pain sensation, cognition, and neuroinflammation. Hence, rapid and specific diagnosis of 2-AG is of great importance in medical neuroscience. Routine methods used in detection of 2-AG are not sensitive and specific. Therefore, the development of new methods in this area has been one of the most important research areas in recent years. Methods. Herein, an innovative immunosensor was developed for quantification of 2-AG. To this end, gold nanostars (GNSs) were synthesized and conjugated with a specific biotinylated antibody activated by EDC/NHS against 2-AG. The resultant bio-conjugate was immobilized on the gold electrode surface and used to detect and analyze 2-arachidonylglycerol antigen by cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy techniques. Results. For the first time, 2-AG protein was measured with an excellent linear range of 0.00048-1 ng/L and lower limit of quantification of 0.00048 ng/L by electroanalysis method. The designed immunosensor showed high sensitivity and specificity in the presence of interfering antigens, which proved its appropriate use in the diagnosis of neurological disorders. Conclusion. The remarkable achievement of the present study is the development of a new immunosensor for the sensitive and accurate detection of 2-AG. The fabricated sensor substrate showed good analytical results for the target analyte. Regardless of the appropriate sensitivity and selectivity of the designed biosensor, the stability of the sensor is low and it is recommended to use it immediately after preparation. Also, the immunosensor engineered in this research was very economical and had a very fast and good performance compared to the usual and traditional methods for detecting 2-AG. Practical Implications. For the first time, 2-AG protein was measured with an excellent linear range of 0.00048-1 ng/L and lower limit of quantification of 0.00048 ng/L by electro analysis method. The designed immunosensor showed high sensitivity and specificity in the presence of interfering antigens, which proved its appropriate use in the diagnosis of neurological disorders.

Correction: Bioconjugation of 2-arachidonoyl glycerol (2-AG) biotinylated antibody with gold nano-flowers toward immunosensing of 2-AG in human plasma samples: a novel immuno-platform for the screening of immunomodulation and neuroprotection using biosensing

Correction for 'Bioconjugation of 2-arachidonoyl glycerol (2-AG) biotinylated antibody with gold nano-flowers toward immunosensing of 2-AG in human plasma samples: a novel immuno-platform for the screening of immunomodulation and neuroprotection using biosensing' by Ahmad Mobed et al., Anal. Methods, 2021, 13, 311-321, https://doi.org/10.1039/D0AY02135K.

An innovative electrochemical immuno-platform towards ultra-sensitive monitoring of 2-arachidonoyl glycerol in samples from rats with sleep deprivation: bioanalysis of endogenous cannabinoids using biosensor technology

The endocannabinoid system (ECS) is a complex of neurotransmitters in the central nervous system and plays a key role in regulating cognitive and physiological processes. 2-Arachidonoylglycerol (2-AG) is one of the imperative endocannabinoids that play key roles in the central nervous system. It acts as a signaling lipid and activates the cannabinoid CB1 receptor. In addition, 2-AG is involved in a variety of physiological functions such as energy balance, emotion, pain sensation, cognition, and neuroinflammation. So, rapid and specific diagnosis of 2-AG is of great importance in medical neuroscience. The development of new methods in this area has been one of the most important research areas in recent years. Herein, an innovative immunosensor is developed for quantification of 2-AG. For this means, gold nanostars (GNS) were synthesized and conjugated with a specific biotinylated antibody against 2-AG. The resultant bioconjugate, a bioreceptor with GNS, was immobilized on the surface of a gold electrode and used for the detection of the antigen based on the immunocomplex formation followed by analysis using different electrochemical techniques. For the first time, 2-AG protein was measured with an excellent linear range of 0.48–1 ng mL⁻¹ and lower limit of quantification of 0.48 ng L⁻¹ by the electroanalysis method. The engineered immunosensor showed high sensitivity and specificity in the presence of interfering antigens, proving its utility in neurological disorder detection. This immunosensor is the first sandwich type immunoassay for the detection of 2-AG in real samples and the first innovation of designing a novel sandwich type immunosensor for this analyte. Also, excellent analytical results are other advantages of this biosensor for the detection of 2-AG in human plasma samples and serum samples of rats under sleep deprivation. So, this is the first report of an immunosensor of 2-AG using a sandwich type immunosensor.

A novel electrochemical immunosensor based gold nanoparticles for the sensitive recognition of 2-AG was introduced.

Bioconjugation of 2-arachidonoyl glycerol (2-AG) biotinylated antibody with gold nano-flowers toward immunosensing of 2-AG in human plasma samples: A novel immuno-platform for the screening of immunomodulation and neuroprotection using biosensing

Human 2-arachidonoylglycerol (2-AG) is an agonist of endocannabinoid system and acts as an important modulator of many physiological processes such as emotional state and pain sensation. Identification and quantification of 2-AG is vital for medical and pathological processes. There are no reports on the measurement of 2-AG in human biofluids using modern methods such as biosensors. This study reports an ultra-sensitive and selective immunosensor to determine endocannabinoids 2-AG in human plasma samples. In this study, gold nano-flowers (AuNFs) were synthesized and conjugated with a specific biotinylated antibody of 2-AG. Bioconjugated composite (bioreceptor with AuNFs) was immobilized on the surface of a gold electrode and used for the monitoring of the antigen (target molecules) based on the immunoreaction process. Moreover, a constructed interface was characterized by field-emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), transmission electron microscopy (TEM) and zeta potential methods. Using the proposed immuno-platform, 2-AG was determined in two dynamic ranges of 0.00024-0.0078 ng L-1 and 2-16 ng L-1 with a lower limit of quantitation (LLOQ) of 0.00024 ng L-1. These results suggest that our immunosensor might be appropriate for an early diagnosis of 2-AG towards the screening of immunomodulatory activity and neuroprotection.

The impact of sleep deprivation on sexual behaviors and FAAH expression in the prefrontal cortex of male rats

Sleep deprivation (SD) causes alterations in the function of the endocannabinoid (EC) system and also results in alteration in many behaviors such as increased anxiety, deteriorated alertness, memory deficits, as well as sexual behaviors. Controversial data about the effects of SD on sexual response are provided. Fatty acid amide hydrolase (FAAH), the enzymes involved in the degradation of the EC system play an important role in the function of the EC system. This study aimed to investigate the effect of REM SD (RSD) and total SD (TSD) on the sexual behaviors and FAAH expression in the prefrontal cortex (PFC) of male rats. RSD was carried out through the flower pot technique for 24 h and 48 h, and TSD also was induced by keeping awake the rats by gentle handling for 6 h. Immediately after RSD and TSD, sexual behaviors were recorded for 45 min. Sexual behaviors were reduced by both types of RSD and TSD. The deleterious effects of 24 h RSD were more severe compared with 6 h of TSD. Serum testosterone concentration was significantly higher after TSD but not RSD compared to the normal sleep (NS) group. FAAH expression in the PFC was significantly reduced after both RSD and TSD compared to the NS group. Given that the function of the EC system has been previously shown to change different behaviors such as sexual activity, our results could suggest that behavioral effects of both types of SD on sexual behavior may partially result from activation of this signaling pathway by the reduction of FAAH in the PFC.

Impacts of epidural electrical stimulation on Wnt signaling, FAAH, and BDNF following thoracic spinal cord injury in rat

Electrical stimulation (ES) has been shown to improve some of impairments after spinal cord injury (SCI), but the underlying mechanisms remain unclear. The Wnt signaling pathways and the endocannabinoid system appear to be modulated in response to SCI. This study aimed to investigate the effect of ES therapy on the activity of canonical/noncanonical Wnt signaling pathways, brain-derived neurotrophic factor (BDNF), and fatty-acid amide hydrolase (FAAH), which regulate endocannabinoids levels. Forty male Wistar rats were randomly divided into four groups: (a) Sham, (b) laminectomy + epidural subthreshold ES, (c) SCI, and (d) SCI + epidural subthreshold ES. A moderate contusion SCI was performed at the thoracic level (T10). Epidural subthreshold ES was delivered to upper the level of T10 segment every day (1 hr/rat) for 2 weeks. Then, animals were killed and immunoblotting was used to assess spinal cord parameters. Results revealed that ES intervention for 14 days could significantly increase wingless-type3 (Wnt3), Wnt7, β-catenin, Nestin, and cyclin D1 levels, as well as phosphorylation of glycogen synthase kinase 3β and Jun N-terminal kinase. Additionally, SCI reduced BDNF and FAAH levels, and ES increased BDNF and FAAH levels in the injury site. We propose that ES therapy may improve some of impairments after SCI through Wnt signaling pathways. Outcomes also suggest that BDNF and FAAH are important players in the beneficial impacts of ES therapy. However, the precise mechanism of BDNF, FAAH, and Wnt signaling pathways on SCI requires further investigation.

Recent advances in the biosensing of neurotransmitters: material and method overviews towards the biomedical analysis of psychiatric disorders

Neurotransmitters are the most important messengers of the nervous system, and any changes in their balances and activities can cause serious neurological, psychiatric and cognitive disorders such as schizophrenia, Alzheimer's disease and Parkinson's disease.

Future drought risk in Africa: Integrating vulnerability, climate change, and population growth

Drought risk refers to the potential losses from hazard imposed by a drought event, and it is generally characterized as a function of vulnerability, hazard, and exposure. In this study, drought risk is assessed at a national level across Africa, and the impacts of climate change, population growth, and socioeconomic vulnerabilities on drought risk are investigated. A rigorous framework is implemented to quantify drought vulnerability considering various sectors including economy, energy and infrastructure, health, land use, society, and water resources. Multi-model and multi-scenario analyses are employed to quantify drought hazard using an ensemble of 10 regional climate models and a multi-scalar drought index. Drought risk is then assessed in each country for 2 climate emission pathways (RCP4.5 and RCP8.5), 3 population scenarios, and 3 vulnerability scenarios during three future periods between 2010 and 2100. Drought risk ratio is quantified, and the role of each component (i.e. hazard, vulnerability, and exposure) is identified, and the associated uncertainties are also characterized. Results show that drought risk is expected to increase in future across Africa with varied rates for different models and scenarios. Although northern African countries indicate aggravating drought hazard, drought risk ratio is found to be highest in central African countries as a consequent of vulnerability and population rise in that region. Results indicate that if no climate change adaptation is implemented, unprecedented drought hazard and risk will occur decades earlier. In addition, controlling population growth is found to be imperative for mitigating drought risk in Africa (even more effective than climate change mitigation), as it improves socioeconomic vulnerability and reduces potential exposure to drought.

Hydrological drought persistence and recovery over the CONUS: A multi-stage framework considering water quantity and quality

Hydrological droughts have considerable negative impacts on water quantity and quality, and understanding their regional characteristics is of crucial importance. This study presents a multi-stage framework to detect and characterize hydrological droughts considering both streamflow and water quality changes. Hydrological droughts are categorized into three stages of growth, persistence, retreat, and water quality variables (i.e., water temperature, dissolved oxygen concentration, and turbidity) are utilized to further investigate drought recovery. The framework is applied to 400 streamflow gauges across the Contiguous United States (CONUS) over the study period of 1950-2016. The method is illustrated for the 2012 US drought, which affected most of the nation. Results reveal the duration, frequency, and severity of historical droughts in various regions as well as their spatial consistencies and heterogeneities. Furthermore, duration of each stage of drought (i.e., growth, persistence, and retreat) is also assessed and the spatial patterns are diagnosed across the CONUS. Considering the water quality variables, increased water temperature (4 °C on average) and reduced dissolved oxygen concentration (2.5 mg/L on average) were observed during drought episodes, both of which impose severe consequences on ecology of natural habitats. On the contrary, turbidity was found to decrease during droughts, and indicate a sudden increase when drought terminates, due to increase in runoff. Varied drought recovery durations are perceived for different water quality variables, and in general, it takes about two more months for water quality variables to recover from a drought, following the hydrological drought termination.

Multi-dimensional assessment of drought vulnerability in Africa: 1960-2100

Drought vulnerability is a complex concept that identifies the capacity to cope with drought, and reveals the susceptibility of a system to the adverse impacts of drought. In this study, a multi-dimensional modeling framework is carried out to investigate drought vulnerability at a national level across the African continent. Data from 28 factors in six different components (i.e. economy, energy and infrastructure, health, land use, society, and water resources) are collected for 46 African countries during 1960-2015, and a composite Drought Vulnerability Index (DVI) is calculated for each country. Various analyses are conducted to assess the reliability and accuracy of the proposed DVI, and the index is evaluated against historical observed drought impacts. Then, regression models are fitted to the historical time-series of DVI for each country, and the models are extrapolated for the period of 2020-2100 to provide three future scenarios of DVI projection (low, medium, and high) based on historical variations and trends. Results show that Egypt, Tunisia, and Algeria are the least drought vulnerable countries, and Chad, Niger, and Malawi are the most drought vulnerable countries in Africa. Future DVI projections indicate that the difference between low- and high-vulnerable countries will increase in future, with most of the southern and northern African countries becoming less vulnerable to drought, whereas the majority of central African countries indicate increasing drought vulnerability. The projected DVIs can be utilized for long-term drought risk analysis as well as strategic adaptation planning purposes.

Escalating heat-stress mortality risk due to global warming in the Middle East and North Africa (MENA)

Climate change will substantially exacerbate extreme temperature and heatwaves. The impacts will be more intense across the Middle East and North Africa (MENA), a region mostly characterized by hot and arid climate, already intolerable for human beings in many parts. In this study, daily climate data from 17 fine-resolution Regional Climate Models (RCMs) are acquired to calculate wet-bulb temperature and investigate the mortality risk for people aged over 65 years caused by excessive heat stress across the MENA region. Spatially adaptive temperature thresholds are implemented for quantifying the mortality risk, and the analysis is conducted for the historical period of 1951-2005 and two future scenarios of RCP4.5 and RCP8.5 during the 2006-2100 period. Results show that the mortality risk will increase in distant future to 8-20 times higher than that of the historical period if no climate change mitigation is implemented. The coastal regions of the Red sea, Persian Gulf, and Mediterranean Sea indicate substantial increase in mortality risk. Nonetheless, the risk ratio will be limited to 3-7 times if global warming is limited to 2 °C. Climate change planning and adaptation is imperative for mitigating heat-related mortality risk across the region.

Protective Effects of Enriched Environment Against Transient Cerebral Ischemia-Induced Impairment of Passive Avoidance Memory and Long-Term Potentiation in Rats

Introduction

Enriched Environment (EE), a complex novel environment, has been demonstrated to improve synaptic plasticity in both injured and intact animals. The present study investigated the capacity of an early environmental intervention to normalize the impairment of passive avoidance memory and Long-Term Potentiation (LTP) induced by transient bilateral common carotid artery occlusion (2-vessel occlusion, 2VO) in rats.

Methods

After weaning, young Wistar rats (22 days old) were housed in EE or Standard Environment (SE) for 40 days. Transient (30-min) incomplete forebrain ischemia was induced 4 days before the passive avoidance memory test and LTP induction.

Results

The transient forebrain ischemia led to impairment of passive avoidance memory and LTP induction in the Perforant Path-Dentate Gyrus (PP-DG) synapses. Interestingly, housing and growing in EE prior to 2VO was found to significantly reverse 2VO-induced cognitive and LTP impairments.

Conclusion

Our results suggest that early housing and growing in EE exhibits therapeutic potential to normalize cognitive and LTP abnormalities induced by 2VO ischemic model in rats.

Effects of environmental enrichment on behavioral deficits and alterations in hippocampal BDNF induced by prenatal exposure to morphine in juvenile rats

Prenatal morphine exposure throughout pregnancy can induce a series of neurobehavioral and neurochemical disturbances by affecting central nervous system development. This study was designed to investigate the effects of an enriched environment on behavioral deficits and changes in hippocampal brain-derived neurotrophic factor (BDNF) levels induced by prenatal morphine in rats. On pregnancy days 11-18, female Wistar rats were randomly injected twice daily with saline or morphine. Offspring were weaned on postnatal day (PND) 21. They were subjected to a standard rearing environment or an enriched environment on PNDs 22-50. On PNDs 51-57, the behavioral responses including anxiety and depression-like behaviors, and passive avoidance memory as well as hippocampal BDNF levels were investigated. The light/dark (L/D) box and elevated plus maze (EPM) were used for the study of anxiety, forced swimming test (FST) was used to assess depression-like behavior and passive avoidance task was used to evaluate learning and memory. Prenatal morphine exposure caused a reduction in time spent in the EPM open arms and a reduction in time spent in the lit side of the L/D box. It also decreased step-through latency and increased time spent in the dark side of passive avoidance task. Prenatal morphine exposure also reduced immobility time and increased swimming time in FST. Postnatal rearing in an enriched environment counteracted with behavioral deficits in the EPM and passive avoidance task, but not in the L/D box. This suggests that exposure to an enriched environment during adolescence period alters anxiety profile in a task-specific manner. Prenatal morphine exposure reduced hippocampal BDNF levels, but enriched environment significantly increased BDNF levels in both saline- and morphine-exposed groups. Our results demonstrate that exposure to an enriched environment alleviates behavioral deficits induced by prenatal morphine exposure and up-regulates the decreased levels of BDNF. BDNF may contribute to the beneficial effects of an enriched environment on prenatal morphine-exposed to rats.

Glucocorticoid-induced impairment of long-term memory retrieval in female rats: influences of estrous cycle and estrogen

Using an inhibitory avoidance (IA) task, the effects of glucocorticoids on memory retrieval in intact and ovariectomized (OVX) female rats were investigated. Young adult female rats were trained in a one trial IA task (1-mA, 3-s footshock). The latency to reenter the dark compartment of the apparatus was recorded in the retention test performed 48h after training. Pre-retrieval injection of corticosterone (CORT, 1, 3, and 10mg/kg) to OVX rats impaired memory retrieval at all doses tested. Similar administration of CORT (3mg/kg) in intact female rats impaired memory retrieval in the estrus phase (when endogenous plasma levels of estrogen are low) but not in the proestrus phase (when endogenous levels of estrogen are high). Concurrent administration of CORT (3mg/kg) and 17-β-estradiol (15μg/kg) in both proestrus and estrous phases impaired memory retrieval. Our findings indicate that the effects of corticosterone on memory retrieval are modulated by the estrous cycle and 17-β-estradiol.

Evaluation of ACE gene I/D polymorphism in Iranian elite athletes

Background:

Angiotensin converting enzyme (ACE) is an important gene, which is associated with the successful physical activity. The ACE gene has a major polymorphism (I/D) in intron 16 that determines its plasma and tissue levels. In this study, we aimed to determine whether there is an association between this polymorphism and sports performance in our studied population including elite athletes of different sports disciplines. We investigated allele frequency and genotype distribution of the ACE gene in 156 Iranian elite athletes compared to 163 healthy individuals. We also investigated this allele frequency between elite athletes in three functional groups of endurance, power, and mixed sports performances.

Materials and Methods:

DNA was extracted from peripheral blood, and polymerase chain reaction (PCR) method was performed on intron 16 of the ACE gene. The ACE genotype was determined for each subject. Statistical analysis was performed by SPSS 15, and results were analyzed by Chi-Square test.

Results:

There was a significant difference in genotype distribution and allele frequency of the ACE gene in athletes and control group (P = 0.05, P = 0.03, respectively). There was also a significant difference in allele frequency of the ACE gene in 3 groups of athletes with different sports disciplines (P = 0.045). Proportion of the ACE gene D allele was greater in elite endurance athletes (37 high-distance cyclists) than two other groups.

Conclusions:

Findings of the present study demonstrated that there is an association between the ACE gene I/D polymorphism and sports performance in Iranian elite athletes.