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Background: Beetroot juice (BRJ) supplementation has been shown to increase sports performance under hypoxic conditions and to improve athletes' recovery. Objectives: In the present study, we aimed to investigate the effect of acute BRJ supplementation on slalom (SL) run performance and muscle soreness (MS) in Alpine skiers at moderate to high altitudes. Methods: Ten male Alpine skiers received 220 mL of BRJ (8.9 mmol/L nitrate) or placebo (PLA) in 2 sessions with a 7-d wash out interval in a randomized, crossover, PLA-controlled, double-blind study. The 90-s box jump (BJ90), agility hexagonal obstacle jump (Hex Jump), and wall-sit tests were measured before on-hill SL runs in both sessions. After the functional tests, SL run performance was measured by time to complete 2 runs on the SL course; immediately after each SL run, the rating of perceived exertion (RPE) was recorded. In addition, perceived MS was recorded using the visual analog scale at 12, 24, and 48 h after the SL runs. Results: The data were meticulously analyzed using 2-way repeated measures analysis of variance and paired t tests with significance set at P < 0.05. The findings were significant, indicating that compared with PLA, BRJ notably improved wall-sit and BJ90 performances (P < 0.05), while a substantial reduction was observed in RPE, Hex Jump, and MS (P < 0.05). A 1.74% shorter time to complete SL runs was observed in the BRJ group compared with the PLA group; however, there were no significant differences between the PLA and BRJ groups (P > 0.05). Conclusions: These results underscore the potential of BRJ supplementation to enhance sports performance and reduce MS in Alpine skiers under hypoxic conditions.
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Introduction: Methods of body composition estimation such as dual-energy X-ray absorptiometry (DXA), anthropometry, and bioimpedance (BIA) are used for the estimation of skeletal muscle mass (SMM) and lean body mass (LBM). No previous studies have examined whether these methods generate comparable results, or whether they are valid by using DXA as the reference. The aims of the present investigation were: (a) to assess the differences between DXA, anthropometry, and BIA in the estimation of SMM and LBM, taking into consideration the impact of sex and hydration status; and (b) to examine the agreement of anthropometry and BIA as compared to DXA for the estimation of SMM and LBM. Methods: A descriptive cross-sectional design was followed with 262 healthy young adults (159 males and 103 females). LBM and SMM were assessed by anthropometry with the formulas from Lee et al. and Kulkarni et al. for LBM; and Kerr (opt a), Kerr (opt b), Lee et al., Poortmans, Matiegka, Martin et al., Drinkwater and Ross, and Heymsfield et al. for SMM; by BIA with the formula reported by the TANITA MC-780-MA software for LBM and SMM; and DXA with the formula reported by the Hologic Horizon software for LBM, and the conversion by Kim et al. for SMM. Results: Significant differences were found for both SMM and LBM in kg, and percentages between most methods and formulas for the overall sample (p < 0.001-0.003) and divided by sex (p < 0.001-0.035). Hydration status did not have a significant effect on the differences between methods and formulas (p = 0.058-0.870). Lin's coefficient revealed limited agreement among the majority of formulas and methods (CCC = 0.007-0.880). The Bland-Altman analysis showed significant differences in most methods and formulas, both in the overall sample and divided by sex, when using SMM and LBM with DXA as the reference (p < 0.001-0.030). Conclusion: There is a lack of agreement between methods and formulas for assessing SMM and LBM. Sex was found to be a significant factor in this analysis. Furthermore, significant differences were observed between most formulas and methods as compared to DXA, except for the equations to estimate SMM with anthropometry by Poortmans.
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Whole-body vibration (WBV) has been employed for performance-enhancing purposes. WBV may positively affect muscular endurance and its underlying neural mechanisms due to an enhanced muscular blood circulation and oxygen uptake. However, the effects of WBV on endurance-related torque signal complexity have been understudied. This study aims to investigate the acute effects of WBV on i) maximal isometric torque production; ii) isometric knee extensors fatigability and iii) torque signal complexity during an isometric endurance task. Thirty adult males performed an isometric intermittent endurance protocol on their dominant lower limb after performing: static half squat with WBV (WBV), static half squat without WBV (HS), and no exercise protocol (CC). For each repetition the maximal torque was identified. The maximal torque of the first repetition was identified as the PeakT. The Mean torque (MTorque) and fatigue index (pFatigue) were calculated as the mean and the percentage decay in torque across the entire set of eighteen repetitions (MTorque0-100 %, pFatigue0-100 %), and across shorter blocks of six repetitions (MTorque0-33 %, pFatigue0-33 %; MTorque34-66 %, pFatigue34-66 %, and MTorque67-100 %, pFatigue67-100 %). Torque fluctuations were analysed computing Sample Entropy (SampEn) and the coefficient of variation (CV). PeakT was significantly higher in CC than in WBV (p < 0.01) and in HS (p < 0.01). PeakT was significantly higher in HS than in WB (p < 0.05). MTorque0-100 %, MTorque0-33 %, MTorque34-66 %, and MTorque67-100 % were significantly higher in CC than in WBV (all p-values <0.01) and in HS (p < 0.01). MTorque67-100 % was significantly higher in HS than in WB (p = 0.049). pFatigue34-66 % was significantly higher in WBV than in CC (p < 0.05) whereas pFatigue67-100 % was significantly higher in CC than in WB (p < 0.01) and in HS (p < 0.01). No effect of condition was observed for SampEn and CV. Acute WBV does not lead to beneficial effects on maximal torque production and isometric knee extensors fatigability. These acute detrimental effects may be related to long-term WBV-related adaptations.
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Unaccustomed eccentric exercise (EE) is protective against muscle damage following a subsequent bout of similar exercise. One hypothesis suggests the existence of an alteration in motor unit (MU) behaviour during the second bout, which might contribute to the adaptive response. Accordingly, the present study investigated MU changes during repeated bouts of EE. During two bouts of exercise where maximal lengthening dorsiflexion (10 repetitions × 10 sets) was performed 3 weeks apart, maximal voluntary isometric torque (MVIC) and MU behaviour (quantified using high-density electromyography; HDsEMG) were measured at baseline, during (after set 5), and post-EE. The HDsEMG signals were decomposed into individual MU discharge timings, and a subset were tracked across each time point. MVIC was reduced similarly in both bouts post-EE (Δ27 vs. 23%, P = 0.144), with a comparable amount of total work performed (â¼1,300 J; P = 0.905). In total, 1,754 MUs were identified and the decline in MVIC was accompanied by a stepwise increase in discharge rate (â¼13%; P < 0.001). A decrease in relative recruitment was found immediately after EE in Bout 1 versus baseline (â¼16%; P < 0.01), along with reductions in derecruitment thresholds immediately after EE in Bout 2. The coefficient of variation of inter-spike intervals was lower in Bout 2 (â¼15%; P < 0.001). Our data provide new information regarding a change in MU behaviour during the performance of a repeated bout of EE. Importantly, such changes in MU behaviour might contribute, at least in part, to the repeated bout phenomenon.
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Weight stigma, and more specifically, anti-fat attitudes, is associated with disordered eating. Furthermore, these anti-fat attitudes influence various appearance ideals. Muscle dysmorphia (MD) is characterized by preoccupation with the muscular ideal and is a potential form of disordered eating commonly experienced by men. Despite theory suggesting that anti-fat attitudes may contribute to MD, research has yet to examine associations between anti-fat attitudes and MD symptoms. Therefore, the current study investigated longitudinal relationships between anti-fat attitudes and MD symptoms. Participants were 269 U.S. men recruited from Prolific who completed three self-report surveys each separated by one month. Primary analyses examined longitudinal relationships between specific anti-fat attitudes and MD symptoms using an adapted three-wave cross-lagged panel model. Results demonstrated that believing that fat people do not have willpower was longitudinally associated with desires to increase muscle size at multiple time points. Furthermore, MD-specific functional impairment predicted fears of becoming fat longitudinally. Practically, men may desire to increase their muscularity to demonstrate their own willpower and distance themselves from anti-fat stereotypes. Thus, clinicians may consider targeting weight stigmatizing attitudes to reduce MD symptom severity among their male clients.
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S100A1, a calcium-binding protein, plays a crucial role in regulating Ca2+ signaling pathways in skeletal and cardiac myocytes via interactions with the ryanodine receptor (RyR) to affect Ca2+ release and contractile performance. Biophysical studies strongly suggest that S100A1 interacts with RyRs but have been inconclusive about both the nature of this interaction and its competition with another important calcium-binding protein, calmodulin (CaM). Thus, high-resolution cryo-EM studies of RyRs in the presence of S100A1, with or without additional CaM, were needed. The elegant work by Weninger et al. demonstrates the interaction between S100A1 and RyR1 through various experiments and confirms that S100A1 activates RyR1 at sub-micromolar Ca2+ concentrations, increasing the open probability of RyR1 channels.
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Late-onset Pompe disease (LOPD) is caused by a genetic deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA), leading to progressive limb-girdle weakness and respiratory impairment. The insidious onset of non-specific early symptoms often prohibits timely diagnosis. This study aimed to validate the high-risk screening criteria for LOPD in the Chinese population. A total of 726 patients were included, including 96 patients under 14 years of age. Dried blood spots (DBS) and tandem mass spectrometry (MS/MS) were employed to evaluate serum GAA activity. Forty-four patients exhibited a decreased GAA activity, 16 (2.2%) of which were confirmed as LOPD by genetic testing. Three previously unreported GAA mutations were also identified. The median diagnostic delay was shortened to 3 years, which excelled the previous retrospective studies. At diagnosis, most patients exhibited impaired respiratory function and/or limb-girdle weakness. Elevated serum creatine kinase (CK) levels were more frequently observed in patients who manifested before age 16. Overall, high-risk screening is a feasible and efficient method to identify LOPD patients at an early stage. Patients over 1 year of age with either weakness in axial and/or proximal limb muscles, or unexplained respiratory distress shall be subject to GAA enzymatic test, while CK levels above 2 times the upper normal limit shall be an additional criterion for patients under 16. This modified high-risk screening criteria for LOPD requires further validation in larger Chinese cohorts.
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The plantaris muscle consists of a small muscular and a long tendinous part and is located at the superficial compartment of the posterior leg. The purpose of the current cadaveric report is to describe a rare variant of the plantaris muscle. During a routine dissection, a three-headed plantaris with two accessory heads was identified with a variant insertion of the two accessory heads. All heads originated from the femur popliteal surface, independently the one from the other. The first head contributed to the long and thin calcaneal tendon, and the two accessory heads were mainly inserted via their musculoaponeurotic expansion into the medial femoral condyle. The plantaris muscle morphological variability has been extensively studied lately. The incidence of the two-headed muscle has been estimated at 1.6%, while the three-headed muscle corresponds to an even rarer variation. This is the third case reported in the English literature, while the insertion of the two accessory heads has never been described before.
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The mdx mouse phenotype, aggravated by chronic exercise on a treadmill, makes this murine model more reliable for the study of Duchenne muscular dystrophy (DMD) and allows the efficacy of therapeutic interventions to be evaluated. This study aims to investigate the effects of photobiomodulation by light-emitting diode (LED) therapy on functional, biochemical and morphological parameters in treadmill-trained adult mdx animals. Mdx mice were trained for 30 min of treadmill running at a speed of 12 m/min, twice a week for 4 weeks. The LED therapy (850 nm) was applied twice a week to the quadriceps muscle throughout the treadmill running period. LED therapy improved behavioral activity (open field) and muscle function (grip strength and four limb hanging test). Functional benefits correlated with reduced muscle damage; a decrease in the inflammatory process; modulation of the regenerative muscular process and calcium signalling pathways; and a decrease in oxidative stress markers. The striking finding of this work is that LED therapy leads to a shift from the M1 to M2 macrophage phenotype in the treadmill-trained mdx mice, enhancing tissue repair and mitigating the dystrophic features. Our data also imply that the beneficial effects of LED therapy in the dystrophic muscle correlate with the interplay between calcium, oxidative stress and inflammation signalling pathways. Together, these results suggest that photobiomodulation could be a potential adjuvant therapy for dystrophinopathies.
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BACKGROUND: Soy-based meat alternatives (SBMA) are becoming increasingly popular, but it is unclear if they have the same anabolic effect on skeletal muscle as animal meat. OBJECTIVE: We aimed to compare the stimulation of skeletal muscle protein synthesis by consumption of one or two 4 oz patties of SBMA with 4 oz (80%protein/20%fat) beef. METHODS: The study design was a randomized controlled trial. Participants were aged 18 to 40 years of age and in good general health with a BMI between 20 and 32 kg/m2. Stable isotope tracer methods were used (L-[ring-2H5] phenylalanine, [U-13C9-15N]- tyrosine and L-[ring-2H4] tyrosine) to quantify the response of muscle protein fractional synthetic rate to consumption of a single beef (4 oz), single SBMA (4 oz), or two 4 oz SBMA patties (8 oz). Whole-body rates of protein synthesis, breakdown and net balance, as well as plasma essential amino acid (EAA) concentrations, were also measured. RESULTS: The increase above basal in muscle protein FSR following consumption of the 4 oz beef patty (0.020 ± 0.016%/hour) was significantly greater than the increase following consumption of 4 oz SBMA (p = 0.021; 0.003 ± 0.010%/hour) but not 8 oz SBMA (p = 0.454; 0.013 ± 0.016%/hour). The maximal EAA concentration was significantly correlated (p = 0.046; r = 0.411) with the change in muscle FSR from the basal to postprandial period. In addition, the change in muscle FSR from the basal to postprandial period was significantly correlated (p = 0.046; r = 0.412) with the corresponding change in whole-body protein synthesis. CONCLUSION: Consumption of a 4 oz beef patty stimulates muscle and whole -body protein synthesis more than a 4 oz SBMA patty and similarly to 8 oz of SBMA. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05197140.
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Sarcopenia, the progressive loss of muscle mass and function, universally affects older adults and is closely associated with frailty and reduced quality of life. Despite the inevitable consequences of sarcopenia and its relevance to healthspan, no pharmacological therapies are currently available. Ghrelin is a gut-released hormone that increases appetite and body weight through acylation. Acylated ghrelin activates its receptor, growth hormone secretagogue receptor 1a (GHSR1a), in the brain by binding to it. Studies have demonstrated that acyl and unacylated ghrelin (UnAG) both have protective effects against acute pathological conditions independent of receptor activation. Here, we investigated the long-term effects of UnAG in age-associated muscle atrophy and contractile dysfunction in mice. Four-month-old and 18-month-old mice were subjected to either UnAG or control treatment for 10 months. UnAG did not affect food consumption or body weight. Gastrocnemius and quadriceps muscle weights were reduced by 20%-30% with age, which was partially protected against by UnAG. Specific force, force per cross-sectional area, measured in isolated extensor digitorum longus muscle was diminished by 30% in old mice; however, UnAG prevented the loss of specific force. UnAG also protected from decreases in mitochondrial respiration and increases in hydrogen peroxide generation of skeletal muscle of old mice. Results of bulk mRNA-seq analysis and our contractile function data show that UnAG reversed neuromuscular junction impairment that occurs with age. Collectively, our data revealed the direct role of UnAG in mitigating sarcopenia in mice, independent of food consumption or body weight, implicating UnAG treatment as a potential therapy against sarcopenia.
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OBJECTIVE: The purpose of this study was to validate a maximum inspiratory pressure test protocol based on the principles of the one-repetition maximum test, assess its test-retest reliability, and establish minimal detectable change in individuals with chronic obstructive pulmonary disease (COPD). METHODS: Forty-nine individuals with COPD were included in the study, of whom 44 individuals attended 2 appointments separated by 7 to 10 days for test-retest reliability. The maximum inspiratory pressure test was performed using a threshold valve device (one-repetition maximum-based protocol) and the digital manometer (reference test). The one-repetition maximum-based protocol consisted of an incremental phase (inspiratory load increase [10 cmH2O] to achieve respiratory failure) and an approach phase (load halfway between the lowest failed attempt and the last valid attempt was prescribed). RESULTS: The concurrent validity of the one-repetition maximum-based protocol for the maximum inspiratory pressure test was good with respect to the reference test (day 1, ICC = 0.81; day 2, ICC = 0.85). The test-retest reliability was excellent (ICC = 0.92), with a standard error of measurement of 6.3 cmH2O and a minimal detectable change of 17.5 cmH2O. CONCLUSION: This study validated a new one-repetition maximum-based protocol for the maximum inspiratory pressure test using an inspiratory muscle training device in individuals with COPD, showing good concurrent validity compared with the reference test, as well as excellent test-retest reliability. The minimal detectable change reported can be interpreted and applied in the clinical setting. IMPACT: There was a need for developing new, inexpensive, simple, and feasible methods for the maximum inspiratory pressure test. The validation of the one-repetition maximum-based protocol addresses this issue, allowing for the appropriate prescription of inspiratory muscle training, favoring its widespread use in people with COPD and therefore improving their physical therapist care.
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PURPOSE: This study aimed to compare the effects of the fascial distortion model (FDM) with and without neuromuscular inhibition technique (NIT) on pain, range of motion and quality of life in patients with piriformis syndrome. METHODS: The study was a randomized controlled trial and 54 participants were randomly allocated by lottery method into two groups. Group A (27 participants) received the FDM with NIT and Group B (27 participants) received the FDM alone. The patients were treated for six weeks, three sessions each week on alternate days. Outcome measurements were taken before the first treatment session and after the last (sixth week) session. Numeric Pain Rating Scale, Sciatica Bothersomeness Index (SBI), and Goniometer were used as outcome measures. SPSS version 25 was used for statistical analysis. RESULTS: Data was normally distributed by the Shapiro-Wilk Test. Statistically significant improvements (p < 0.05) were observed in the FDM with NIT than in FDM alone. Both groups show significant results in all outcome measures with paired sample t-tests (p < 0.05). CONCLUSION: This study concluded that participants with piriformis syndrome show more improvement in the FDM with NIT than the FDM group alone. TRIAL REGISTRATION NUMBER: NCT05404607.
This study provides the evidence-based result of the Fascial Distortion Model in patients with piriformis syndrome.The combined effects of both treatment techniques; Fascial Distortion Model and Neuromuscular Inhibition Technique can provide more effective results for piriformis syndrome.
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OBJECTIVE: Hip fracture (HF) has been described as the "last fracture of life" in the elderly, so the assessment of HF risk is extremely important. Currently, few studies have examined the relationship between imaging data from chest computed tomography (CT) and HF. This study demonstrated that pectoral muscle index (PMI) and vertebral body attenuation values could predict HF, aiming to opportunistically assess the risk of HF in patients without bone mineral density (BMD) based on chest CT for other diseases. METHODS: In the retrospective study, 800 participants who had both BMD and chest CT were enrolled from January 2021 to January 2024. After exclusion, 472 patients were finally enrolled, divided into the healthy control (HC) group and the HF group. Clinical data were collected, and differences between the two groups were compared. A predictive model was constructed based on the PMI and CT value of the fourth thoracic vertebra (T4HU) by logistic regression analysis, and the predictive effect of the model was analyzed by using the receiver operating characteristic (ROC) curve. Finally, the clinical utility of the model was analyzed using decision curve analysis (DCA) and clinical impact curves. RESULTS: Both PMI and T4HU were lower in the HF group than in the HC group (p < 0.05); low PMI and low T4HU were risk factors for HF. The predictive model incorporating PMI and T4HU on the basis of age and BMI had excellent diagnostic efficacy with an area under the curve (AUC) of 0.865 (95% confidence interval [CI]: 0.830-0.894, p < 0.01), sensitivity and specificity of 0.820 and 0.754, respectively. The clinical utility of the model was validated using calibration curves and DCA. The AUC of the predictive model incorporating BMD based on age and BMI was 0.865 (95% CI: 0.831-0.895, p < 0.01), with sensitivity and specificity of 0.698 and 0.711, respectively. There was no significant difference in diagnostic efficacy between the two models (p = 0.967). CONCLUSIONS: PMI and T4HU are predictors of HF in patients. In the absence of dual-energy x-ray absorptiometry (DXA), the risk of HF can be assessed by measuring the PMI and T4HU on chest CT examination due to other diseases, and further treatment can be provided in time to reduce the incidence of HF.
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The detection of a secondary inorganic phosphate (Pi) resonance, a possible marker of mitochondrial content in vivo, using phosphorus magnetic resonance spectroscopy (31P-MRS), poses technical challenges at 3 Tesla (T). Overcoming these challenges is imperative for the integration of this biomarker into clinical research. To evaluate the repeatability and reliability of measuring resting skeletal muscle alkaline Pi (Pialk) using with 31P-MRS at 3 T. After an initial set of experiments on five subjects to optimize the sequence, resting 31P-MRS of the quadriceps muscles were acquired on two visits (~4 days apart) using an intra-subjects design, from 13 sedentary to moderately active young male and female adults (22 ± 3 years old) within a whole-body 3 T MR system. Measurement variability attributed to changes in coil position, shimming procedure, and spectral analysis were quantified. 31P-MRS data were acquired with a 31P/-proton (1H) dual-tuned surface coil positioned on the quadriceps using a pulse-acquire sequence. Test-retest absolute and relative repeatability was analyzed using the coefficient of variation (CV) and intra-class correlation coefficients (ICC), respectively. After sequence parameter optimization, Pialk demonstrated high intra-subject repeatability (CV: 10.6 ± 5.4%, ICC: 0.80). Proximo-distal change in coil position along the length of the quadriceps introduced Pialk quantitation variability (CV: 28 ± 5%), due to magnetic field inhomogeneity with more distal coil locations. In contrast, Pialk measurement variability due to repeated shims from the same muscle volume (0.40 ± 0.09mM; CV: 6.6%), and automated spectral processing (0.37 ± 0.01mM; CV: 2.3%), was minor. The quantification of Pialk in skeletal muscle via surface coil 31P-MRS at 3 T demonstrated excellent reproducibility. However, caution is advised against placing the coil at the distal part of the quadriceps to mitigate shimming inhomogeneity.
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OBJECTIVE: The aim of this study was to investigate the feasibility of muscle CT radiomics in identifying gout. MATERIALS AND METHODS: A total of 30 gout patients and 20 non-gout cases with CT examinations of ankles were analyzed by using the methods of CT radiomics. CT radiomics features of the soleus muscle were extracted using the software of a 3D slicer, and then gout cases and non-gout cases were compared. The radiomics features that were significantly different between the two groups were then processed with machine learning methods. Receiver operating characteristic curve analysis was used to evaluate the diagnostic performance. RESULTS: Five CT radiomics features were significantly different between gout cases and non-gout cases (P < 0.05). In the logic regression, the AUC, sensitivity, specificity, and accuracy were 0.738, 77% (46/60), 70% (28/40), and 74% (74/100), respectively. In the Random forest, Xgboost, and support vector machine analysis, the accuracy was 0.901, 0.833, and 0.875, respectively. CONCLUSION: From this study, it can be concluded that muscle CT radiomics is feasible in identifying gout.
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Atherosclerosis remains a major challenge to global healthcare despite decades of research and constant trials of novel therapeutic approaches. One feature that makes atherosclerosis treatment so elusive is an insufficient understanding of its origins and the early stages of the pathological process, which limits our means of effective prevention of the disease. Macrovascular pericytes are cells with distinct shapes that are located in the arterial wall of larger vessels and are in many aspects similar to microvascular pericytes that maintain the functionality of small vessels and capillaries. This cell type combines the residual contractile function of smooth muscle cells with a distinct stellar shape that allows these cells to make numerous contacts between themselves and the adjacent endothelial layer. Moreover, pericytes can take part in the immune defense and are able to take up lipids in the course of atherosclerotic lesion development. In growing atherosclerotic plaques, the morphology and function of pericytes change dramatically due to phagocytic and synthetic phenotypes that are actively involved in lipid accumulation and extracellular matrix synthesis. In this review, we summarize our knowledge of this less-studied cell type and its role in atherosclerosis.