Levels of Circulating Progenitor Cells, Cardiovascular Outcomes and Death

Future Directions of Chronic Total Occlusion Management: Identifying the Right Patient for Intervention With a Focus on Biomarkers

The management of a chronic total occlusion (CTO) of a coronary artery has been a conundrum in interventional cardiology, as revascularization has not been proven to provide a mortality benefit. However, there are subgroups of patients with a CTO that have high levels of ischemia on myocardial perfusion imaging and high circulating levels of high sensitivity troponin-I (hsTn-I) and N terminal pro-brain natriuretic peptide (NT pro-BNP) that are at a particularly high-risk for adverse cardiovascular events. These high-risk subgroups of patients with a CTO may have not been well represented in prior clinical trials, and may gain a mortality benefit from revascularization of the CTO. Conversely, patients with low levels of ischemia and these biomarkers are at lower risk and may not gain a mortality benefit from revascularization of their CTO. It is important for future randomized controlled trials to investigate the efficacy of CTO PCI in patients with elevated biomarkers and high ischemic burden on myocardial perfusion imaging to determine if patients at high-risk gain a mortality benefit from revascularization.

Liraglutide improves peripheral perfusion and markers of angiogenesis and inflammation in people with type 2 diabetes and peripheral artery disease: An 18-month follow-up of a randomized clinical trial

AIMS

In a six-month randomized clinical trial, improved peripheral perfusion has been shown with liraglutide, associated with favourable vascular effects in people with type 2 diabetes and peripheral artery disease (PAD). We aimed to evaluate the durability of these benefits and to elucidate some mechanisms underlying liraglutide's effect over an 18-month follow-up.

METHODS

STARDUST was a randomized clinical trial which compared liraglutide up to 1.8 mg/day with tailored therapeutic prescriptions to manage cardiovascular risk factors in 55 participants with type 2 diabetes and PAD. We report data of people who have reached the 18-month follow-up for the primary outcome (transcutaneous oxygen pressure, TcPO2) and also for additional secondary outcomes (markers of inflammation, angiogenesis and kidney function), as well as glycemic and metabolic parameters. TcPO2 was assessed with transcutaneous oximetry. Circulating levels of angiogenic progenitor cells and serum inflammation markers were evaluated by flow cytometry and enzyme-linked immunosorbent assay, respectively.

RESULTS

Compared with the control group, significant differences favouring the liraglutide group were observed at 18 months for TcPO2 [estimated treated difference (95% CI), 10.9 mmHg (7.6 to 14.1 mmHg), p < 0.001]. At 18 months of follow-up, participants in the liraglutide group, as compared with those in the control group, had a significant reduction in urine albumin to creatinine ratio (estimated difference, -103.9 mg/g Cr, 95%CI, -170.8 to -37.1, p = 0.003), C-reactive protein (-0.5 mg/dL, 95%CI, -0.8 to -0.2, p = 0.002), as well as interleukin-6 (-32.6 pg/mL, 95%CI, -54.6 to -10.5, p = 0.004). Compared with the control group, participants in the liraglutide group showed significantly higher concentrations of circulating progenitor cells and endothelial progenitor cells at both 6 and 18 months, for CD34+, CD133+, KDR+, CD34+/KDR+ and CD34+/CD133+/KDR+. Liraglutide was also associated with a higher increase in vascular endothelial growth factor A at 18 months (70.1 pg/mL, 95%CI, 44.7 to 95.4, p < 0.001).

CONCLUSIONS

In people with type 2 diabetes and PAD, liraglutide increased peripheral perfusion, with amelioration of markers of angiogenesis and inflammation over an 18-month follow-up.

Trimethylamine-N-Oxide (TMAO) as a Rising-Star Metabolite: Implications for Human Health

The intestinal microbiota, hosting trillions of microorganisms that inhabit the gastrointestinal tract, functions as a symbiotic organism that plays a crucial role in regulating health by producing biologically active molecules that can enter systemic circulation. Among them, trimethylamine-N-oxide (TMAO), an organic compound derived from dietary sources and microbial metabolism, has emerged as a critical biomarker linking diet, the gut microbiota, and the host metabolism to various pathological conditions. This comprehensive review highlights TMAO's biosynthesis, physiological functions, and clinical significance, focusing on its mechanistic contributions to cardiovascular and neurodegenerative diseases. Notably, TMAO-mediated pathways include endothelial dysfunction, inflammation via NLRP3 inflammasome activation, and cholesterol metabolism disruption, which collectively accelerate atherosclerosis and disease progression. Nonetheless, this work underscores the innovative potential of targeting TMAO through dietary, nutraceutical, and microbiota-modulating strategies to mitigate its pathological effects, marking a transformative approach in the prevention and management of TMAO-related disorders.

Circulating CD34+ Cells: A New Biomarker of Residual Pulmonary Vascular Obstruction after Pulmonary Embolism

Pulmonary embolism (PE) is a life-threatening condition with long-term complications, including residual pulmonary vascular obstruction (RPVO). RPVO is associated with an increased risk of venous thromboembolism recurrence, chronic symptoms, and reduced quality of life. We hypothesize that an endothelial activation and vascular injury play a central role in the pathophysiology of RPVO. This prospective monocentric study investigates the potential of circulating biomarkers, including CD34⁺ cells, circulating endothelial cells (CECs), and platelet-derived growth factor BB (PDGF-BB), as indicators of vascular sequelae and predictors of RPVO. We included 56 patients with a first episode of PE. Biomarker levels were measured at PE diagnosis and six months later, coinciding with RPVO assessment using ventilation-perfusion lung scans. This defined groups of patients with (RPVO ≥ 10%) and without (RPVO < 10%) perfusion defects. Associations between biomarker levels, presence of perfusion defects, and clinical parameters were analyzed. At PE diagnosis, CEC and PDGF-BB levels were significantly elevated in patients compared to healthy controls, while CD34⁺ levels showed no difference. At the six-month follow-up, patients with perfusion defects exhibited significantly lower CD34⁺ cell levels compared to those without (median 1440 cells/mL vs. 2960 cells/mL). No significant differences in CEC or PDGF-BB levels were observed at follow-up. In conclusion, low CD34⁺ cell levels at RPVO assessment suggest a decreased regenerative potential contributing to thrombus persistence. CD34⁺ cells may serve as biomarkers for perfusion defects and warrant further study for their potential role in guiding clinical management of PE complications.

Advancements in utilizing CD34+ stem cells for repairing diabetic vascular damage

Diabetes-related vascular damage is a frequent complication of diabetes that results in structural and functional impairment of blood vessels. This damage significantly heightens the risk of cardiovascular events. CD34+ stem cells have shown great potential in the treatment of diabetes-related vascular damage due to their differentiation and vascular repair capabilities. This article provides a review of the research hotspots on the role and mechanisms of CD34+ stem cells in the repair of diabetes-related vascular damage, including changes in cell quantity and function during diabetes, as well as the latest research on activating, protecting, or repairing these cells to prevent or treat vascular damage. The article also summarizes the impact of diabetes on the mobilization and function of CD34+ stem cells, emphasizing how diabetes negatively affects their ability to promote angiogenesis. These deficits can result in various complications, including issues with small blood vessels, coronary heart disease, foot problems, and retinal complications. On the clinical side, the article highlights the positive effects of CD34+ stem cell therapy in improving vascular function and tissue repair in diabetic patients, while also mentioning the inconsistencies in results between diabetes models and clinical studies, which necessitate further research to optimize treatment strategies. It emphasizes the importance of enhancing the mobilization, homing, and repair capabilities of CD34+ stem cells, as well as combining them with other treatment methods, to develop more effective strategies for treating diabetes-related vascular damage.

Flow Cytometric Determination of Circulating Progenitor Cells in Patients With Pulmonary Arterial Hypertension: A Systematic Review

Pulmonary arterial hypertension (PAH) is characterized by progressive narrowing and obliteration of distal, pre-capillary pulmonary vessels. Yet, noninvasive biomarkers that reflect this disease-defining process are lacking. A systematic review of PAH studies that measured circulating progenitor cells (CPCs) or circulating endothelial cells (CECs) in PAH by flow cytometry was performed to understand how future studies, leveraging state-of-the-art single-cell analyses, can advance the field. The study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews. Of the 2422 studies identified, 20 met inclusion criteria. Nineteen studies measured CPCs by flow cytometry, only one study examined CECs. A total of 647 PAH patients were included across all 19 CPC studies. Marker schemes chosen to define CPCs, and the methods of flow cytometry used, varied significantly across studies. Meta-analysis of a subgroup of CPC studies (n = 8) similarly identified a significant amount of heterogeneity even amongst studies using the same marker scheme. In conclusion, a systematic review of CPC studies in PAH patients reveals the limitations of the current literature. Future studies should include contemporary risk assessments, disease duration, reporting of comorbid conditions, and serial sampling over time. Furthermore, methods that incorporate best practices for detecting rare cell populations by flow cytometry are essential and should be reported in sufficient detail in future publications. With the emergence of single-cell technologies, future studies of circulating progenitor and endothelial cells in PAH remain relevant and may incorporate several insights from the current review to build upon the existing literature.

Exposure to air pollution and cardiovascular risk in young children - a pilot project

OBJECTIVE

To examine relationships between traffic-related air pollution (TRAP) and markers of pre-clinical cardiovascular risk in young children.

STUDY DESIGN

We studied a cohort of healthy children ages 2-5 recruited from pediatric primary care sites (n = 122). We obtained child weight, height, blood pressure and hair nicotine levels. A blood sample was obtained for biomarkers of systemic inflammation, oxidation, and prevalence of circulating endothelial progenitor cells. This manuscript represents a secondary analysis. TRAP exposure (particulate levels, nitrogen dioxide, nitrogen oxides, and proximity to major roadways) was assessed using national air pollution data based on child's census tract of residence.

RESULTS

TRAP exposure had significant positive associations with prevalence of two of the three EPC subtypes (CD34 + /CD133 + /CD45- and CD133 + /CD45-) in unadjusted correlations. In a linear regression model, adjusting for sex, age, race, ethnicity, body mass index, parental education, child insurance, and secondhand smoke exposure, one EPC subtype (CD133 + /CD45-) had a positive significant correlation to every TRAP measure. No significant relationships between air pollution and measures of inflammation and oxidation was found.

CONCLUSION

Our findings of the upregulation of EPCs may signal a response to early vascular damage during early childhood due to air pollution exposure.

IMPACT

Traffic-related air pollution (TRAP) - known cardiovascular risk factor during adulthood Current pilot study in very young children shows upregulation of cells which protect the endothelial lining of blood vessels (endothelial progenitor cells, EPCs) Upregulation of EPCs aligns with other cardiovascular risks during childhood (obesity, prematurity, type 1 diabetes) Demonstrated with TRAP exposure lower than EPA threshold Response to air pollution may be protective of cardiovascular damage during early childhood.

Circulating endothelial progenitor cells and inflammatory markers in type 1 diabetes after an acute session of aerobic exercise

Objective

To determine circulating endothelial progenitor cells (EPC) counts and levels of inflammatory markers in individuals with and without type 1 diabetes mellitus (T1DM) in response to an intense aerobic exercise session.

Subjects and methods

In total, 15 adult men with T1DM and 15 healthy individuals underwent a 30-minute aerobic exercise session on a cycle ergometer at 60% of the peak heart rate. The EPC count (CD45dim/CD34+/KDR+), tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) levels were measured before and 60 minutes after the session.

Results

We found no difference within or between groups regarding EPC counts before and after the aerobic exercise: healthy individuals, 0.02% change (95% confidence interval [CI] -0.04%-0.08%); individuals with T1DM, 0.00% (95%CI -0.01%-0.01%). We also found no difference in TNF-α levels before and after exercise in healthy individuals (210.2, interquartile range [IQR] 142.1-401.2 pg/mL and 191.3, IQR 136.4-350.5 pg/mL, respectively) and in patients with T1DM (463.8, IQR 201.4-4306.0 pg/mL and 482.7, IQR 143.8-4304.3 pg/mL, respectively). Similarly, no difference in IL-6 levels was observed before and after exercise in healthy individuals (148.2, IQR 147.5-148.6 pg/mL and 148.2, IQR 147.7-148.6 pg/mL, respectively) and individuals with T1DM (147.2, IQR 145.9-147.7 pg/mL and 147.2, IQR 146.8-147.8 pg/mL, respectively).

Conclusions

Patients with T1DM and healthy controls had comparable EPC responses to aerobic exercise, most likely due to the absence of a chronic inflammatory state.

Cardioimmunology in Health and Diseases: Impairment of the Cardio-Spleno-Bone Marrow Axis Following Myocardial Infarction in Diabetes Mellitus

A comprehensive understanding of the cardio-spleen-bone marrow immune cell axis is essential for elucidating the alterations occurring during the pathogenesis of diabetes mellitus (DM). This study investigates the dynamics of immune cell kinetics in DM after myocardial infarction (MI) over time. MI was induced in diabetic and healthy control groups using C57BL/N6 mice, with sacrifices occurring at days 1, 3, 7, and 28 post-MI to collect heart, peripheral blood (PB), spleen, and bone marrow (BM) samples. Cell suspensions from each organ were isolated and analyzed via flow cytometry. Additionally, the endothelial progenitor cell-colony-forming assay (EPC-CFA) was performed using mononuclear cells derived from BM, PB, and the spleen. The results indicated that, despite normal production in BM and the spleen, CD45+ cells were lower in the PB of DM mice at days 1 to 3. Further analysis revealed a reduction in total and pro-inflammatory neutrophils (N1s) in PB at days 1 to 3 and in the spleen at days 3 to 7 in DM mice, suggesting that DM-induced alterations in splenic neutrophils fail to meet the demand in PB and ischemic tissues. Infiltrating macrophages (total, M1, M2) were reduced at day 3 in the DM-ischemic heart, with total and M1 (days 1-3) and M2 (days 3-7) macrophages being significantly decreased in DM-PB compared to controls, indicating impaired macrophage recruitment and polarization in DM. Myeloid dendritic cells (mDCs) in the heart were higher from days 1 to 7, which corresponded with the enhanced recruitment of CD8+ cells from days 1 to 28 in the DM-infarcted myocardium. Total CD4+ cells decreased in DM-PB at days 1 to 3, suggesting a delayed adaptive immune response to MI. B cells were reduced in PB at days 1 to 3, in myocardium at day 3, and in the spleen at day 7, indicating compromised mobilization from BM. EPC-CFA results showed a marked decrease in definitive EPC colonies in the spleen and BM from days 1 to 28 in DM mice compared to controls in vitro, highlighting that DM severely impairs EPC colony-forming activity by limiting the differentiation of EPCs from primitive to definitive forms. Taking together, this study underscores significant disruptions in the cardio-spleen-bone marrow immune cell axis following MI in DM, revealing delayed innate and adaptive immune responses along with impaired EPC differentiation.

Circulating Progenitor Cells and Coronary Collaterals in Chronic Total Occlusion

BACKGROUND

The role of circulating progenitor cells (CPC) in collateral formation that occurs in the presence of chronic total occlusions (CTO) of a coronary artery is not well established. In stable patients with a CTO, we investigated whether CPC levels are associated with (a) collateral development and (b) ischemic burden, as measured by circulating high sensitivity troponin-I (hsTn-I) levels.

METHODS

CPCs were enumerated by flow cytometry as CD45med+ blood mononuclear cells expressing CD34 and both CD34 and CD133 epitopes. The association between CPC counts and both Rentrop collateral grade (0, 1, 2, or 3) and hsTn-I levels were evaluated using multivariate regression analysis, after adjusting for demographic and clinical characteristics.

RESULTS

In 89 patients (age 65.5, 72% male, 27% Black), a higher CPC count was positively associated with a higher Rentrop collateral grade; [CD34+ adjusted odds ratio (OR) 1.49 95% confidence interval (CI) (0.95, 2.34) P = 0.082] and [CD34+/CD133+ OR 1.57 95% CI (1.05, 2.36) P = 0.028]. Every doubling of CPC counts was also associated with lower hsTn-I levels [CD34+ β -0.35 95% CI (-0.49, -0.15) P = 0.002] and [CD34+/CD133+ β -0.27 95% CI (-0.43, -0.08) P = 0.009] after adjustment.

CONCLUSION

Individuals with higher CPC counts have greater collateral development and lower ischemic burden in the presence of a CTO.

Responses of Endothelial Progenitor Cells to Chronic and Acute Physical Activity in Healthy Individuals

Endothelial progenitor cells (EPCs) are circulating cells of various origins that possess the capacity for renewing and regenerating the endothelial lining of blood vessels. During physical activity, in response to factors such as hypoxia, changes in osmotic pressure, and mechanical forces, endothelial cells undergo intense physiological stress that results in endothelial damage. Circulating EPCs participate in blood vessel repair and vascular healing mainly through paracrine signalling. Furthermore, physical activity may play an important role in mobilising this important cell population. In this narrative review, we summarise the current knowledge on the biology of EPCs, including their characteristics, assessment, and mobilisation in response to both chronic and acute physical activity in healthy individuals.

Human Cord Blood Endothelial Progenitor Cells and Pregnancy Complications (Preeclampsia, Gestational Diabetes Mellitus, and Fetal Growth Restriction)

Hemangioblasts give rise to endothelial progenitor cells (EPCs), which also express the cell surface markers CD133 and c-kit. They may differentiate into the outgrowth endothelial cells (OECs) that control neovascularization in the developing embryo. According to numerous studies, reduced levels of EPCs in circulation have been linked to human cardiovascular disorders. Furthermore, preeclampsia and senescence have been linked to levels of EPCs produced from cord blood. Uncertainties surround how preeclampsia affects the way EPCs function. It is reasonable to speculate that preeclampsia may have an impact on the function of fetal EPCs during the in utero period; however, the present literature suggests that maternal vasculopathies, including preeclampsia, damage fetal circulation. Additionally, the differentiation potential and general activity of EPCs may serve as an indicator of the health of the fetal vascular system as they promote neovascularization and repair during pregnancy. Thus, the purpose of this review is to compare-through the assessment of their quantity, differentiation potency, angiogenic activity, and senescence-the angiogenic function of fetal EPCs obtained from cord blood for normal and pregnancy problems (preeclampsia, gestational diabetes mellitus, and fetal growth restriction). This will shed light on the relationship between the angiogenic function of fetal EPCs and pregnancy complications, which could have an effect on the management of long-term health issues like metabolic and cardiovascular disorders in offspring with abnormal vasculature development.

The association between circulating CD34+CD133+ endothelial progenitor cells and reduced risk of Alzheimer's disease in the Framingham Heart Study

Aim

Endothelial dysfunction has been associated with both cerebrovascular pathology and Alzheimer's disease (AD). However, the connection between circulating endothelial cells and the risk of AD remains uncertain. The objective was to leverage data from the Framingham Heart Study to investigate various circulating endothelial subtypes and their potential correlations with the risk of AD.

Methods

The study conducted data analyses using Cox proportional hazard regression and linear regression methods. Additionally, genome-wide association study (GWAS) was carried out to further explore the data.

Results

Among the eleven distinct circulating endothelial subtypes, only circulating endothelial progenitor cells (EPCs) expressing CD34+CD133+ were found to be negatively and dose-dependently associated with reduced AD risk. This association persisted even after adjusting for age, sex, years of education, apolipoprotein E (APOE) ε4 status, and various vascular diseases. Particularly noteworthy was the significant association observed in individuals with hypertension and cerebral microbleeds. Consistently, positive associations were identified between CD34+CD133+ EPCs and specific brain regions, such as higher proportions of circulating CD34+CD133+ cells correlating with increased volumes of white matter and the hippocampus. Additionally, a GWAS study unveiled that CD34+CD133+ cells influenced AD risk specifically in individuals with homozygous genotypes for variants in two stem cell-related genes: kirre like nephrin family adhesion molecule 3 (KIRREL3, rs580382 CC and rs4144611 TT) and exocyst complex component 6B (EXOC6B, rs61619102 CC).

Conclusions

The findings suggest that circulating CD34+CD133+ EPCs possess a protective effect and may offer a new therapeutic avenue for AD, especially in individuals with vascular pathology and those carrying specific genotypes of KIRREL3 and EXOC6B genes.

Association of circulating CD34+ cells level and prognosis after ischemic stroke

BACKGROUND

CD34 is a transmembrane phosphoglycoprotein and a marker of hematopoietic and nonhematopoietic stem/progenitor cells. In experimental studies, CD34+ cells are rich sources of endothelial progenitor cells and can promote neovascularization and endothelial repair. The potential role of CD34+ cells in stroke patients remains unclear.

AIMS

We aimed to assess the prognostic effect of circulating CD34+ cell levels on the risk of vascular events and functional prognosis in stroke patients.

PATIENTS AND METHODS

In this prospective observational study, patients with ischemic stroke were consecutively enrolled within 1 week of onset and followed up for 1 year. Patients were divided into three groups according to tertiles of the level of circulating CD34+ cells (Tertile 1, <0.51/µL; Tertile 2, 0.51-0.96/µL; and Tertile 3, >0.96/µL). The primary outcome was a composite of major adverse cardiovascular events (MACEs), including nonfatal stroke, nonfatal acute coronary syndrome, major peripheral artery disease, and vascular death. The secondary outcomes included the modified Rankin scale (mRS) scores.

RESULTS

A total of 524 patients (mean age, 71.3 years; male, 60.1%) were included. High CD34+ cell levels were associated with younger age (p < 0.001) and low National Institutes of Health Stroke Scale scores at admission (p = 0.010). No significant differences were found in the risk of MACEs among the three groups (annual rates: 15.0%, 13.4%, and 12.6% in Tertiles 1, 2, and 3, respectively; log-rank p = 0.70). However, there were significant differences in the mRS scores at 3 months (median (interquartile range); 2 (1-4), 1 (1-3), and 1 (0-2) in Tertiles 1, 2, and 3, respectively; p = 0.010) and 1 year (3 (1-4), 2 (1-4), and 1 (0-3); p < 0.001) among these groups. After multivariable adjustments, a higher CD34+ cell level was independently associated with good functional outcomes (mRS score of 0-2) at 3 months (adjusted odds ratio (OR), 1.43; 95% confidence interval (CI), 1.01-2.05) and 1 year (adjusted OR, 1.53; 95% CI, 1.09-2.16).

CONCLUSION

Although no correlations were found between circulating CD34+ cell levels and vascular event risk, elevated CD34+ cell levels were associated with favorable functional recovery in stroke patients.

DATA ACCESS STATEMENT

Data supporting the findings of this study are available from the corresponding author on reasonable request.

CLINICAL TRIAL REGISTRATION

The TWMU Stroke Registry is registered at https://upload.umin.ac.jp as UMIN000031913.

Acute psychological stress-induced progenitor cell mobilization and cardiovascular events

OBJECTIVE

Certain brain activation responses to psychological stress are associated with worse outcomes in CVD patients. We hypothesized that elevated acute psychological stress, manifesting as greater activity within neural centers for emotional regulation, mobilizes CPC from the bone marrow to the peripheral blood and predicts future cardiovascular events.

METHODS

In 427 patients with stable CAD undergoing a laboratory-based mental stress (MS) test, CPCs were enumerated using flow cytometry as CD34-expressing mononuclear cells (CD34+) before and 45 min after stress. Changes in brain regional blood flow with MS were measured using high resolution-positron emission tomography (HR-PET). Association between the change in CPC with MS and the risk of cardiovascular death or myocardial infarction (MI) during a 5-year follow-up period was analyzed.

RESULTS

MS increased CPC counts by a mean of 150 [630] cells/mL (15%), P < 0.001. Greater limbic lobe activity, indicative of activation of emotion-regulating centers, was associated with greater CPC mobilization (P < 0.005). Using Fine and Gray models after adjustment for demographioc, clinical risk factors and medications use, greater CPC mobilization was associated with a higher adjusted risk of adverse events; a rise of 1000 cells/mL was associated with a 50% higher risk of cardiovascular death/MI [hazards ratio, 1.5, 95% confidence interval, 1.1-2.2).

CONCLUSION

Greater limbic lobe activity, brain areas involved in emotional regulation, is associated with MS-induced CPC mobilization. This mobilization isindependently associated with cardiovascular events. These findings provide novel insights into mechanisms through which psychological stressors modulate cardiovascular risk.

Vascular Regenerative Cell Deficiencies in South Asian Adults

BACKGROUND

South Asian individuals shoulder a disproportionate burden of cardiometabolic diseases.

OBJECTIVES

The purpose of this study was to determine if vascular regenerative cell content varies significantly between South Asian and White European people.

METHODS

Between January 2022 and January 2023, 60 South Asian and 60 White European adults with either documented cardiovascular disease or established diabetes with ≥1 other cardiovascular risk factor were prospectively enrolled. Vascular regenerative cell content in venous blood was enumerated using a flow cytometry assay that is based on high aldehyde dehydrogenase (ALDHhi) activity and cell surface marker phenotyping. The primary outcome was the difference in frequency of circulating ALDHhi progenitor cells, monocytes, and granulocytes between the 2 groups.

RESULTS

Compared with White European participants, those of South Asian ethnicity were younger (69 ± 10 years vs 66 ± 9 years; P < 0.05), had lower weight (88 ± 19 kg vs 75 ± 13 kg; P < 0.001), and exhibited a greater prevalence of type 2 diabetes (62% vs 92%). South Asian individuals had markedly lower circulating frequencies of pro-angiogenic ALDHhiSSClowCD133+ progenitor cells (P < 0.001) and ALDHhiSSCmidCD14+CD163+ monocytes with vessel-reparative capacity (P < 0.001), as well as proportionally more ALDHhi progenitor cells with high reactive oxygen species content (P < 0.05). After correction for sex, age, body mass index, and glycated hemoglobin, South Asian ethnicity was independently associated with lower ALDHhiSSClowCD133+ cell count.

CONCLUSIONS

South Asian people with cardiometabolic disease had less vascular regenerative and reparative cells suggesting compromised vessel repair capabilities that may contribute to the excess vascular risk in this population. (The Role of South Asian vs European Origins on Circulating Regenerative Cell Exhaustion [ORIGINS-RCE]; NCT05253521).

Improved prediction of long-term kidney outcomes in people with type 2 diabetes by levels of circulating haematopoietic stem/progenitor cells

AIM/HYPOTHESIS

We examined whether prediction of long-term kidney outcomes in individuals with type 2 diabetes can be improved by measuring circulating levels of haematopoietic stem/progenitor cells (HSPCs), which are reduced in diabetes and are associated with cardiovascular risk.

METHODS

We included individuals with type 2 diabetes who had a baseline determination of circulating HSPCs in 2004-2019 at the diabetes centre of the University Hospital of Padua and divided them into two groups based on their median value per ml of blood. We collected updated data on eGFR and albuminuria up to December 2022. The primary endpoint was a composite of new-onset macroalbuminuria, sustained ≥40% eGFR decline, end-stage kidney disease or death from any cause. The analyses were adjusted for known predictors of kidney disease in the population with diabetes.

RESULTS

We analysed 342 participants (67.8% men) with a mean age of 65.6 years. Those with low HSPC counts (n=171) were significantly older and had a greater prevalence of hypertension, heart failure and nephropathy (45.0% vs 33.9%; p=0.036), as evidenced by lower eGFR and higher albuminuria at baseline. During a median follow-up of 6.7 years, participants with high vs low HSPC counts had lower rates of the composite kidney outcome (adjusted HR 0.69 [95% CI 0.49, 0.97]), slower decline in eGFR and a similar increase in albuminuria. Adding the HSPC information to the risk score of the CKD Prognosis Consortium significantly improved discrimination of individuals with future adverse kidney outcomes.

CONCLUSIONS/INTERPRETATION

HSPC levels predict worsening of kidney function and improve the identification of individuals with type 2 diabetes and adverse kidney outcomes over and beyond a clinical risk score.

Impaired Angiogenic Function of Fetal Endothelial Progenitor Cells via PCDH10 in Gestational Diabetes Mellitus

Maternal hyperglycemia, induced by gestational diabetes mellitus (GDM), has detrimental effects on fetal vascular development, ultimately increasing the risk of cardiovascular diseases in offspring. The potential underlying mechanisms through which these complications occur are due to functional impairment and epigenetic changes in fetal endothelial progenitor cells (EPCs), which remain less defined. We confirm that intrauterine hyperglycemia leads to the impaired angiogenic function of fetal EPCs, as observed through functional assays of outgrowth endothelial cells (OECs) derived from fetal EPCs of GDM pregnancies (GDM-EPCs). Notably, PCDH10 expression is increased in OECs derived from GDM-EPCs, which is associated with the inhibition of angiogenic function in fetal EPCs. Additionally, increased PCDH10 expression is correlated with the hypomethylation of the PCDH10 promoter. Our findings demonstrate that in utero exposure to GDM can induce angiogenic dysfunction in fetal EPCs through altered gene expression and epigenetic changes, consequently increasing the susceptibility to cardiovascular diseases in the offspring of GDM mothers.

Prognostic Value of Endothelial Progenitor Cells in Acute Myocardial Infarction Patients

Objective

To determine prognostic role of endothelial progenitor cells (EPCs) in intensive care patients with acute myocardial infarction (AMI).

Materials and Methods

From December 2018 to July 2021, a total of 91 eligible patients with AMI were consecutively examined in a single intensive care unit (ICU) in China. Patients with a history of acute coronary artery disease were excluded from the study. Samples were collected within 24 hr of onset of symptoms. EPCs, defined as coexpression of CD34+/CD133+ cells or CD133+/CD34+/KDR+, were studied using flow cytometry and categorized by quartiles. Based on the 28-days mortality outcome, the patients were further divided into two groups: death and survival. The study incorporated various variables, including cardiovascular risk factors such as body mass index, hypertension, diabetes, hypercholesterolemia, atherosclerotic burden, and medication history, as well as clinical characteristics such as APACHEⅡscore, central venous-arterial carbon dioxide difference (GAP), homocysteine, creatinine, C-reactive protein, HbAlc, and cardiac index. Cox regression analysis was employed to conduct a multivariate analysis.

Results

A total of 91 patients with AMI who were admitted to the ICU were deemed eligible for inclusion in the study. Among these patients, 23 (25.3%) died from various causes during the follow-up period. The counts of EPCs were found to be significantly higher in the survival group compared to the death group (P < 0.05). In the univariate analysis, it was observed that the 28-days mortality rate was associated with the several factors, including the APACHEⅡscore (P=0.00), vasoactive inotropic score (P=0.03), GAP (P=0.00), HCY (P=0.00), creatinine (P=0.00), C-reactive protein (P=0.00), HbAlc (P=0.00), CI (P=0.01), quartiles of CD34+/CD133+ cells (P=0.00), and quartiles of CD34+/CD133+/KDR+ cells (P=0.00). CD34+/CD133+/KDR+ cells retained statistical significance in Cox regression models even after controlling for clinical variables (HR: 6.258 × 10-10 and P=0.001). Nevertheless, no significant correlation was observed between CD34+/CD133+ cells and all-cause mortality.

Conclusions

The decreased EPCs levels, especially for CD34+/CD133+/KDR+ cells subsets, were an independent risk factor for 28-days mortality in AMI patients.

A phase I, first-in-human study to evaluate the safety and tolerability, pharmacokinetics, and pharmacodynamics of MRG-001 in healthy subjects

Preclinical studies demonstrate that pharmacological mobilization and recruitment of endogenous bone marrow stem cells and immunoregulatory cells by a fixed-dose drug combination (MRG-001) improves wound healing, promotes tissue regeneration, and prevents allograft rejection. In this phase I, first-in-human study, three cohorts receive subcutaneous MRG-001 or placebo, every other day for 5 days. The primary outcome is safety and tolerability of MRG-001. Fourteen subjects received MRG-001 and seven received a placebo. MRG-001 is safe over the selected dose range. There are no clinically significant laboratory changes. The intermediate dose group demonstrates the most significant white blood cell, stem cell, and immunoregulatory cell mobilization. PBMC RNA sequencing and gene set enrichment analysis reveal 31 down-regulated pathways in the intermediate MRG-001 dose group compared with no changes in the placebo group. MRG-001 is safe across all dose ranges. MRG-001 may be a clinically useful therapy for immunoregulation and tissue regeneration (ClinicalTrials.gov: NCT04646603).

The cardio-renal-metabolic connection: a review of the evidence

Type 2 diabetes (T2D), cardiovascular disease (CVD) and chronic kidney disease (CKD), are recognized among the most disruptive public health issues of the current century. A large body of evidence from epidemiological and clinical research supports the existence of a strong interconnection between these conditions, such that the unifying term cardio-metabolic-renal (CMR) disease has been defined. This coexistence has remarkable epidemiological, pathophysiologic, and prognostic implications. The mechanisms of hyperglycemia-induced damage to the cardio-renal system are well validated, as are those that tie cardiac and renal disease together. Yet, it remains controversial how and to what extent CVD and CKD can promote metabolic dysregulation. The aim of this review is to recapitulate the epidemiology of the CMR connections; to discuss the well-established, as well as the putative and emerging mechanisms implicated in the interplay among these three entities; and to provide a pathophysiological background for an integrated therapeutic intervention aiming at interrupting this vicious crosstalks.

Significance of Endothelial Dysfunction Amelioration for Sodium-Glucose Cotransporter 2 Inhibitor-Induced Improvements in Heart Failure and Chronic Kidney Disease in Diabetic Patients

Beyond lowering plasma glucose levels, sodium-glucose cotransporter 2 inhibitors (SGLT2is) significantly reduce hospitalization for heart failure (HF) and retard the progression of chronic kidney disease (CKD) in patients with type 2 diabetes. Endothelial dysfunction is not only involved in the development and progression of cardiovascular disease (CVD), but is also associated with the progression of CKD. In patients with type 2 diabetes, hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia induce the development of endothelial dysfunction. SGLT2is have been shown to improve endothelial dysfunction, as assessed by flow-mediated vasodilation, in individuals at high risk of CVD. Along with an improvement in endothelial dysfunction, SGLT2is have been shown to improve oxidative stress, inflammation, mitochondrial dysfunction, glucotoxicity, such as the advanced signaling of glycation end products, and nitric oxide bioavailability. The improvements in endothelial dysfunction and such endothelium-derived factors may play an important role in preventing the development of coronary artery disease, coronary microvascular dysfunction and diabetic cardiomyopathy, which cause HF, and play a role in retarding CKD. The suppression of the development of HF and the progression of CKD achieved by SGLT2is might have been largely induced by their capacity to improve vascular endothelial function.

CARdioimaging in Lung Cancer PatiEnts Undergoing Radical RadioTherapy: CARE-RT Trial

BACKGROUND

Non-small-cell lung cancer (NSCLC) is a common, steady growing lung tumour that is often discovered when a surgical approach is forbidden. For locally advanced inoperable NSCLC, the clinical approach consists of a combination of chemotherapy and radiotherapy, eventually followed by adjuvant immunotherapy, a treatment that is useful but may cause several mild and severe adverse effect. Chest radiotherapy, specifically, may affect the heart and coronary artery, impairing heart function and causing pathologic changes in myocardial tissues. The aim of this study is to evaluate the damage coming from these therapies with the aid of cardiac imaging.

METHODS

This is a single-centre, prospective clinical trial. Patients with NSCLC who are enrolled will undergo computed tomography (CT) and magnetic resonance imaging (MRI) before chemotherapy 3 months, 6 months, and 9-12 months after the treatment. We expect to enrol 30 patients in 2 years.

CONCLUSIONS

Our clinical trial will be an opportunity not only to highlight the timing and the radiation dose needed for pathological cardiac tissue changes to happen but will also provide useful data to set new follow-up schedules and strategies, keeping in mind that, more often than not, patients affected by NSCLC may present other heart- and lung-related pathological conditions.

Human Hematopoietic Stem/Progenitor Cells in Type One Diabetes Mellitus Treatment: Is There an Ideal Candidate?

Type 1 diabetes mellitus (T1DM) is a highly prevalent autoimmune disease causing the destruction of pancreatic islet β-cells. The resulting insulin production deficiency leads to a lifelong need for insulin re-placement therapy, systemic complications, and reduced life quality and expectancy. Cell therapy has been extensively attempted to restore insulin independence (IID), and autologous nonmyeloablative hematopoietic stem cell transplantation (AHST) has appeared to give the most promising results, but with a highly variable quote of patients achieving IID across the studies. We performed a comprehensive review of the trials involving stem cells, and in particular AHST, for the treatment of T1DM. We then pooled the patients enrolled in the different trials and looked for the patient characteristics that could be associated with the achievement of IID. We found a significantly higher probability of achieving IID in older patients (OR 1.17, 95%CI 1.06–1.33, p = 0.002) and a significantly lower probability in patients with a history of ketoacidosis (OR 0.23, 95%CI 0.06–0.78, p = 0.023). This suggests that there could be a population of patients more likely to benefit from AHST, but further data would be required to depict the profile of the ideal candidate.

Circulating progenitor cells and outcomes in patients with coronary artery disease

BACKGROUND

Low quantities of circulating progenitor cells (CPCs), specifically CD34+ populations, reflect impairment of intrinsic regenerative capacity. This study investigates the relationship between subsets of CPCs and adverse outcomes.

METHODS

1366 individuals undergoing angiography for evaluation of coronary artery disease (CAD) were enrolled into the Emory Cardiovascular Biobank. Flow cytometry identified CPCs as CD45med blood mononuclear cells expressing the CD34 epitope, with further enumeration of hematopoietic CPCs as CD133+/CXCR4+ cells and endothelial CPCs as vascular endothelial growth factor receptor-2 (VEGFR2+) cells. Adjusted Cox or Fine and Gray's sub-distribution hazard regression models analyzed the relationship between CPCs and 1) all-cause death and 2) a composite of cardiovascular death and non-fatal myocardial infarction (MI).

RESULTS

Over a median 3.1-year follow-up period (IQR 1.3-4.9), there were 221 (16.6%) all-cause deaths and 172 (12.9%) cardiovascular deaths/MIs. Hematopoietic CPCs were highly correlated, and the CD34+/CXCR4+ subset was the best independent predictor. Lower counts (≤median) of CD34+/CXCR4+ and CD34+/VEGFR2+ cells independently predicted all-cause mortality (HR 1.46 [95% CI 1.06-2.01], p = 0.02 and 1.59 [95% CI 1.15-2.18], p = 0.004) and cardiovascular death/MI (HR 1.50 [95% CI 1.04-2.17], p = 0.03 and 1.47 [95% CI 1.01-2.03], p = 0.04). A combination of low CD34+/CXCR4+ and CD34+/VEGFR2+ CPCs predicted all-cause death (HR 2.1, 95% CI 1.4-3.0; p = 0.0002) and cardiovascular death/MI (HR 2.0, 95% CI 1.3-3.2; p = 0.002) compared to those with both lineages above the cut-offs.

CONCLUSIONS

Lower levels of hematopoietic and endothelial CPCs indicate diminished endogenous regenerative capacity and independently correlate with greater mortality and cardiovascular risk in patients with CAD.

Glucagon-Like Peptide 1 Receptor Agonists Versus Sodium-Glucose Cotransporter 2 Inhibitors for Atherosclerotic Cardiovascular Disease in Patients With Type 2 Diabetes

Beyond improving hemoglobin A1c (HbA1c) in adults with type 2 diabetes, glucagon-like peptide 1 receptor agonists (GLP-1RA) have been approved for reducing risk of major adverse cardiovascular events (MACE) with established cardiovascular disease (CVD) or multiple CV risk factors. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) also reduced the risk for the primary composite CV outcome in patients with type 2 diabetes at high risk for CV events. In the American Diabetes Association (ADA) and European Association of Study in Diabetes (EASD) consensus report 2022, there is the description "In people with established atherosclerotic CVD (ASCVD) or with a high risk for ASCVD, GLP-1RA were prioritized over SGLT2i"; however, the evidence supporting such statement is limited. Therefore, we studied the superiority of GLP-1RA over SGLT2i for prevention of ASCVD from various viewpoints. We could not find a meaningful difference in the risk reduction in three-point MACE (3P-MACE), mortality due to any cause, mortality due to CV cause and nonfatal myocardial infarction between GLP-1RA and SGLT2i trials. The risk of nonfatal stroke decreased in all five GLP-1RA trials; however, two of three SGLT2i trials showed an increase in risk of nonfatal stroke. The risk of hospitalization for heart failure (HHF) decreased in all three SGLT2i trials, and one GLP-1RA trial showed an increase in risk of HHF. The risk reduction of HHF in SGLT2i trials was greater than that in GLP-1RA trials. These findings were consistent with current systematic reviews and meta-analyses. The risk reduction of 3P-MACE was significantly and negatively correlated with changes in HbA1c (R = -0.861, P = 0.006) and body weight (R = -0.895, P = 0.003) in GLP-1RA and SGLT2i trials. The studies using SGLT2i failed to reduce carotid intima media thickness (cIMT), the surrogate marker for atherosclerosis; however, several studies using GLP-1RA successfully reduced cIMT in patients with type 2 diabetes. Compared with SGLT2i, GLP-1RA had a higher probability of decreasing serum triglyceride. GLP-1RA have multiple vascular biological anti-atherogenic properties.

Circulating Endothelial Progenitor Cells Reduce the Risk of Alzheimer's Disease

Cerebrovascular damage coexists with Alzheimer's disease (AD) pathology and increases AD risk. However, it is unclear whether endothelial progenitor cells reduce AD risk via cerebrovascular repair. By using the Framingham Heart Study (FHS) offspring cohort, which includes data on different progenitor cells, the incidence of AD dementia, peripheral and cerebrovascular pathologies, and genetic data (n = 1,566), we found that elevated numbers of circulating endothelial progenitor cells with CD34+CD133+ co-expressions had a dose-dependent association with decreased AD risk (HR = 0.67, 95% CI: 0.46-0.96, p = 0.03) after adjusting for age, sex, years of education, and APOE ε4. With stratification, this relationship was only significant among those individuals who had vascular pathologies, especially hypertension (HTN) and cerebral microbleeds (CMB), but not among those individuals who had neither peripheral nor central vascular pathologies. We applied a genome-wide association study (GWAS) and found that the number of CD34+CD133+ cells impacted AD risk depending on the homozygous genotypes of two genes: KIRREL3 rs580382 CC carriers (HR = 0.31, 95% CI: 0.17-0.57, p<0.001), KIRREL3 rs4144611 TT carriers (HR = 0.29, 95% CI: 0.15-0.57, p<0.001), and EXOC6B rs61619102 CC carriers (HR = 0.49, 95% CI: 0.31-0.75, p<0.001) after adjusting for confounders. In contrast, the relationship did not exist in their counterpart genotypes, e.g. KIRREL3 TT/CT or GG/GT carriers and EXOC6B GG/GC carriers. Our findings suggest that circulating CD34+CD133+ endothelial progenitor cells can be therapeutic in reducing AD risk in the presence of cerebrovascular pathology, especially in KIRREL3 and EXOC6B genotype carriers.

Hematopoietic Stem Cells and Metabolic Deterioration in Alström Syndrome, a Rare Genetic Model of the Metabolic Syndrome

Alström syndrome (AS) is a rare genetic disease caused by ALMS1 mutations, characterized by short stature, and vision and hearing loss. Patients with AS develop the metabolic syndrome, long-term organ complications, and die prematurely. We explored the association between AS and a shortage of hematopoietic stem/progenitor cells (HSPCs), which is linked to metabolic diseases and predicts diabetic complications. We included patients with AS at a national referral center. We measured HSPCs with flow cytometry at baseline and follow-up. We followed patients up to January 2022 for metabolic worsening and end-organ damage. We evaluated HSPC levels and mobilization as well as bone marrow histology in a murine model of AS. In 23 patients with AS, we found significantly lower circulating HSPCs than in healthy blood donors (-40%; P = .002) and age/sex-matched patients (-25%; P = .022). Longitudinally, HSPCs significantly declined by a further 20% in patients with AS over a median of 36 months (interquartile range 30-44). Patients with AS who displayed metabolic deterioration over 5.3 years had lower levels of HSPCs, both at baseline and at last observation, than those who did not deteriorate. Alms1-mutated mice were obese and insulin resistant and displayed significantly reduced circulating HSPCs, despite no overt hematological abnormality. Contrary to what was observed in diabetic mice, HSPC mobilization and bone marrow structure were unaffected. We found depletion of HSPCs in patients with AS, which was recapitulated in Alms1-mutated mice. Larger and longer studies will be needed to establish HSPCs shortage as a driver of metabolic deterioration leading to end-organ damage in AS.

The Long Telling Story of "Endothelial Progenitor Cells": Where Are We at Now?

Endothelial progenitor cells (EPCs): The name embodies years of research and clinical expectations, but where are we now? Do these cells really represent the El Dorado of regenerative medicine? Here, past and recent literature about this eclectic, still unknown and therefore fascinating cell population will be discussed. This review will take the reader through a temporal journey that, from the first discovery, will pass through years of research devoted to attempts at their definition and understanding their biology in health and disease, ending with the most recent evidence about their pathobiological role in cardiovascular disease and their recent applications in regenerative medicine.

A cohort study of circulating progenitor cells after ST-segment elevation and non-ST segment elevation myocardial infarction in non-diabetic and diabetic patients

Background

Myocardial infarction induces elevation of progenitor cells in the circulation, a reparative response inhibited by type-2 diabetes.

Objectives

Determine if myocardial infarct severity and diabetes interactively influence the migratory activity of CD34+/CXCR4+ progenitor cells and if the migratory test predicts cardiac outcomes.

Materials and methods

A longitudinal study was conducted on patients with or without diabetes with a STEMI or NSTEMI. CD34+/CXCR4+ cells were measured in the peripheral blood using flow cytometry, and migratory activity was tested in vitro on cells isolated from samples collected on days 0 and 4 post-infarct. Cardiac function was assessed at three months using cardiac MRI.

Results

Of 1,149 patients screened, 71 (6.3%) were eligible and consented. Fifty had STEMI (16 with diabetes) and 21 NSTEMI (8 with diabetes). The proportion of CD34+/CXCR4+ cells within blood mononuclear cells was 1.96 times higher after STEMI compared with NSTEMI (GMR = 1.96, 95% CI 0.87, 4.37) and 1.55 times higher in patients with diabetes compared to patients without diabetes (GMR = 1.55, 95% CI 0.77, 3.13). In the latter, STEMI was associated with a 2.42-times higher proportion of migrated CD34 + /CXCR4 + cells compared with NSTEMI (GMR = 2.42, 95% CI 0.66, 8.81). In patients with diabetes, the association was the opposite, with a 55% reduction in the proportion of migrated CD34+/CXCR4+ cells. No statistically significant associations were observed between the frequency in peripheral blood or in vitro migration capacity of CD34+/CXCR4+ cells and MRI outcomes.

Conclusion

We document the interaction between infarct and diabetes on the migratory activity of CD34+/CXCR4+ cells. The test did not predict functional outcomes in the studied cohort.

Effects of dulaglutide on endothelial progenitor cells and arterial elasticity in patients with type 2 diabetes mellitus

Background

Randomised controlled trial showed that dulaglutide can reduce the risk of atherosclerotic cardiovascular disease (ASCVD) in patients with type 2 diabetes mellitus (T2DM), but the underlying mechanisms remain unclear. This study aimed to investigate the effect of dulaglutide on the number and function of endothelial progenitor cells (EPCs) in the peripheral blood of patients with T2DM and its role in improving arterial elasticity, so as to determine potential mechanisms of preventive effect of dulaglutide on ASCVD.

Methods

Sixty patients with T2DM were treated with 1000 mg/day of metformin and randomly divided into two groups for 12 weeks: metformin monotherapy group (MET group, n = 30), and metformin combined with dulaglutide group (MET-DUL group, n = 30). Before and after treatment, the number of CD34⁺CD133⁺KDR⁺ EPCs and the brachial–ankle pulse wave velocity (baPWV) of the participants were measured, and EPC proliferation, adhesion, migration, and tubule formation were assessed in vitro.

Results

There were no significant differences in the number and function of EPCs and baPWV changes in MET group (P > 0.05). In MET-DUL group, nitric oxide (NO) levels and the number of EPCs increased after treatment (P < 0.05), while the levels of C-reactive protein (CRP), interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), advanced glycation end products (AGEs), and baPWV decreased (P < 0.05). EPC proliferation, adhesion, migration, and tubule formation abilities were significantly enhanced (P < 0.05). Correlation analysis showed that in MET-DUL group, the changes in CRP, IL-6, TNF-α, and AGEs were negatively correlated with the number of EPCs and their proliferation and migration abilities (P < 0.05). Body weight, NO, CRP, and IL-6 levels were independent factors affecting the number of EPCs (P < 0.05). The changes in number of EPCs, proliferation and migration abilities of EPCs, and NO and IL-6 levels were independent influencing factors of baPWV changes (P < 0.05).

Conclusion

Dulaglutide can increase the number and function of EPCs in peripheral blood and improve arterial elasticity in patients with T2DM; it is accompanied by weight loss, inflammation reduction, and high NO levels. Dulaglutide regulation of EPCs may be a mechanism of cardiovascular protection.

Coronary Artery Restenosis in Women by History of Preeclampsia

Background A history of preeclampsia is associated with increased risk of coronary artery disease and experimental evidence suggests that a history of preeclampsia also increases the risk of restenosis. However, the extent to which a history of preeclampsia is associated with risk of restenosis after percutaneous coronary intervention in women is unknown. Methods and Results We included 6065 parous women aged ≤65 years with first percutaneous coronary intervention on 9452 segments 2006 to 2017, linking nationwide data on percutaneous coronary intervention and delivery history in Sweden. Main outcomes were clinical restenosis and target lesion revascularization within 2 years. We accounted for segment-, procedure-, and patient-related potential predictors of restenosis in proportional hazards regression models. Restenosis occurred in 345 segments (3.7%) and target lesion revascularization was performed on 383 patients (6.3%). A history of preeclampsia was neither significantly associated with risk of restenosis (predictor-accounted hazard ratio [HR], 0.71 [95% CI, 0.41-1.23]) nor target lesion revascularization (0.74 [95% CI, 0.51-1.07]) compared with a normotensive pregnancy history. When term and preterm preeclampsia were investigated separately, segments in women with a history of term preeclampsia had a lower risk of restenosis (predictor-accounted HR, 0.45 [95% CI, 0.21-0.94]). A history of preeclampsia was not significantly associated with death by any cause within 2 years of the index procedure (predictor-accounted HR 1.06, [95% CI, 0.62-1.80]). Conclusions A history of preeclampsia was not associated with increased risk of restenosis but instead some evidence pointed to a decreased risk. To facilitate future studies and allow for replication, concomitant collection of data on pregnancy complication history and percutaneous coronary intervention outcomes in women is warranted.

Change in Circulating Levels of Endothelial Progenitor Cells and Sexual Function in Women With Type 1 Diabetes

CONTEXT

Endothelial progenitor cells (EPCs), which are involved in the mechanisms of vascular repair and sexual function, are decreased in diabetic women compared with general population.

OBJECTIVE

This work aimed to investigate the circulating levels of EPCs and the change in sexual function during the menstrual cycle in women with type 1 diabetes (T1DM) compared with healthy women.

METHODS

This case-control observational study was conducted at the Unit of Endocrinology and Metabolic Diseases at University Hospital "Luigi Vanvitelli'' of Naples. Participants included 36 women with T1DM and 64 age-matched healthy controls. EPCs were quantified by flow cytometry and sexual function was assessed using the Female Sexual Function Index (FSFI) and the Female Sexual Distress Scale. All assessments were made at the follicular, ovulatory, and luteal phases of the same menstrual cycle. Main outcome measures included differences in EPCs levels and sexual function between patients and controls.

RESULTS

Compared with controls, women with T1DM showed significantly lower levels of both CD34 + (P < .001) and CD34 + CD133 + cells (P < .001) in the ovulatory phase, and CD34 + KDR + cells both in the ovulatory phase and in the luteal phase (P < .001 for both). Diabetic women showed significantly lower total FSFI scores and higher FSDS score than control women in all phases of the menstrual cycle. FSFI total score was predicted by both CD34 + CD133 + and CD34 + KDR + cells in the follicular phase, CD34 + and CD34 + KDR + CD133 + cells in the ovulatory phase, and CD34 + KDR + and CD34 + KDR + CD133 + cells in the luteal phase.

CONCLUSION

Women with T1DM show lower levels of EPCs during the menstrual cycle compared with controls. EPCs count predicts sexual function in this selected population.

Glycaemic Control Achieves Sustained Increases of Circulating Endothelial Progenitor Cells in Patients Hospitalized for Decompensated Diabetes: An Observational Study

BACKGROUND AND AIM

Diabetes reduces the levels of circulating endothelial progenitor cells (EPCs), which contribute to vascular homeostasis. In turn, low EPCs levels predict progression of chronic complications. Several studies have shown that hyperglycaemia exerts detrimental effects on EPCs. Improvement in glucose control with glucose-lowering medications is associated with an increase of EPCs, but only after a long time of good glycaemic control. In the present study, we examined the effect of a rapid glycaemic amelioration on EPC levels in subjects hospitalized for decompensated diabetes.

METHODS

We used flow cytometry to quantify EPCs (CD34⁺/CD133⁺KDR⁺) in patients hospitalized for/with decompensated diabetes at admission, at discharge, and 2 months after the discharge. During hospitalization, all patients received intensive insulin therapy.

RESULTS

Thirty-nine patients with type 1 or type 2 diabetes were enrolled. Average (± SEM) fasting glucose decreased from 409.2 ± 25.9 mg/dl at admission to 190.4 ± 12.0 mg/dl at discharge and to 169.0 ± 10.3 at 2 months (both p < 0.001). EPCs (per million blood cells) significantly increased from hospital admission (13.1 ± 1.4) to discharge (16.4 ± 1.1; p = 0.022) and remained stable after 2 months (15.5 ± 1.7; p = 0.023 versus baseline). EPCs increased significantly more in participants with newly-diagnosed diabetes than in those with pre-existing diabetes. The increase in EPCs was significant in type 1 but not in type 2 diabetes and in those without chronic complications.

CONCLUSION

In individuals hospitalized for decompensated diabetes, insulin therapy rapidly increases EPC levels for up to 2 months. EPC defect, reflecting impaired vascular repair capacity, may be reversible in the early diabetes stages.

Co-Culture of Bone Marrow Mesenchymal Stem Cells Regulates the Fibrotic Response of Endometrial Stromal Cells

This study explored the protective effects and mechanisms of bone marrow mesenchymal stem cells (BMSCs) on the fibrotic response of endometrial stromal cells. The endometrial cells were isolated from intrauterine adhesions (IUA) patients and assigned into control group, TGF-β1 group, BMSC group which was co-cultured with BMSCs in presence of TGF-β1; Exo group (treated with BMSCs-originated exosomes); Exo-inhibitor group (treated with exosome-specific inhibitors) followed by analysis of α-SMA and Vimentin level, cell viability and expression of TGFBR2, TGFβ-1, Fibronectin (FN), α-SMA, Collagen 1α1 (Col1a1), Smad2/3 and p-Smad2/3. After TGF-β1 treatment, cells exhibited higher expression of p-Smad2/3, TGFBR2, FN, TGF-SMA and COL1A1 along with reduced cell proliferation. However, BMSCs-originated exosomes or co-culture with BMSCs reversed these changes which could be inverted by exosome-specific inhibitors. In conclusion, BMSCs-originated exosomes and BMSCs exerted an anti-fibrosis effect, which was possibly through regulation of TGFβ1/Smad2/Smad3 signalling pathway in endometrial stromal cells.

Impaired haematopoietic stem / progenitor cell traffic and multi-organ damage in diabetes

During antenatal development, hematopoietic stem/progenitor cells (HSPCs) arise from a specialized endothelium and migrate from the extraembryonic mesoderm to the fetal liver before establishing hematopoiesis in the bone marrow (BM). It is still debated whether, in adulthood, HSPCs display such ontologic overlap with vascular cells and capacity for endothelial differentiation. Yet, adult HSPCs retain a prominent migratory activity and traffic in the bloodstream to secondary lymphoid organs and all peripheral tissues, before eventually returning to the BM. While patrolling parenchymatous organs, HSPCs locate close to the vasculature, where they establish local hematopoietic islands and contribute to tissue homeostasis by paracrine signals. Solid evidence shows that diabetes mellitus jeopardizes the traffic of HSPCs from BM to the circulation and peripheral tissues, a condition called “mobilopathy.” A reduction in the levels of circulating HSPCs is the most immediate and apparent consequence, which has been consistently observed in human diabetes, and is strongly associated with future risk for multi-organ damage, including micro- and macro-angiopathy. But the shortage of HSPCs in the blood is only the visible tip of the iceberg. Abnormal HSPC traffic results from a complex interplay among metabolism, innate immunity, and hematopoiesis. Notably, mobilopathy is mechanistically connected with diabetes-induced myelopoiesis. Impaired traffic of HSPCs and enhanced generation of pro-inflammatory cells synergize for tissue damage and impair the resolution of inflammation. We herein summarize the current evidence that diabetes affects HSPC traffic, which are the causes and consequences of such alteration, and how it contributes to the overall disease burden.

Liraglutide preserves CD34+ stem cells from dysfunction Induced by high glucose exposure

Background

Glucagon like peptide-1 receptor agonists (GLP-1RAs) have shown to reduce mortality and cardiovascular events in patients with type 2 diabetes mellitus (T2DM). Since the impairment in number and function of vasculotrophic circulating CD34⁺ hematopoietic stem progenitor cells (HSPCs) in T2D has been reported to increase cardiovascular (CV) risk, we hypothesized that one of the mechanisms whereby GLP-1 RAs exert CV protective effects may be related to the ability to improve CD34⁺ HSPC function.

Methods

In cord blood (CB)-derived CD34⁺ HSPC, the expression of GLP-1 receptor (GLP-1R) mRNA, receptor protein and intracellular signaling was evaluated by RT-qPCR and Western Blot respectively. CD34⁺ HSPCs were exposed to high glucose (HG) condition and GLP-1RA liraglutide (LIRA) was added before as well as after functional impairment. Proliferation, CXCR4/SDF-1α axis activity and intracellular ROS production of CD34⁺ HSPC were evaluated.

Results

CD34⁺ HSPCs express GLP-1R at transcriptional and protein level. LIRA treatment prevented and rescued HSPC proliferation, CXCR4/SDF-1α axis activity and metabolic imbalance from HG-induced impairment. LIRA stimulation promoted intracellular cAMP accumulation as well as ERK1/2 and AKT signaling activation. The selective GLP-1R antagonist exendin (9–39) abrogated LIRA-dependent ERK1/2 and AKT phosphorylation along with the related protective effects.

Conclusion

We provided the first evidence that CD34⁺ HSPC express GLP-1R and that LIRA can favorably impact on cell dysfunction due to HG exposure. These findings open new perspectives on the favorable CV effects of GLP-1 RAs in T2DM patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01486-9.

Hematopoietic and Nonhematopoietic p66Shc Differentially Regulates Stem Cell Traffic and Vascular Response to Ischemia in Diabetes

Aims: Peripheral artery disease (PAD) is a severe complication of diabetes, characterized by defective traffic of hematopoietic stem/progenitor cells (HSPCs). We examined the hematopoietic versus nonhematopoietic role of p66Shc in regulating HSPC traffic and blood flow recovery after ischemia in diabetic mice. Results: Using streptozotocin-induced diabetes, chimeric mice with green fluorescent protein (GFP)⁺ bone marrow (BM), and the hind limb ischemia model, we found that the physiologic mobilization and homing of HSPCs were abolished by diabetes, along with impaired vascular recovery. Hematopoietic deletion of p66Shc, obtained by transplanting p66Shc^-/- BM cells into wild-type (Wt) recipients, but not nonhematopoietic deletion, constrained hyperglycemia-induced myelopoiesis, rescued postischemic HSPC mobilization, and improved blood flow recovery in diabetic mice. In Wt diabetic mice transplanted with BM cells from GFP⁺p66Shc^-/- mice, the amount of HSPCs homed to ischemic muscles was greater than in mice transplanted with GFP⁺p66Shc^+/+ cells, with recruited cells displaying higher expression of adhesion molecules and Vegf. In 40 patients with diabetes, p66Shc gene expression in mononuclear cells was correlated with myelopoiesis and elevated in the presence of PAD. In 13 patients with diabetes and PAD, p66Shc expression in HSPC-mobilized peripheral blood cells was inversely correlated with VEGF expression. Innovation: For the first time, we dissect the role of hematopoietic versus nonhematopoietic p66Shc in regulating HSPC traffic and ischemic responses. Conclusion: Hematopoietic deletion of p66Shc was sufficient to rescue HSPC mobilization and homing in diabetes after ischemia and improved blood flow recovery. Inhibiting p66Shc in blood cells may be a novel strategy to counter PAD in diabetes. Antioxid. Redox Signal. 36, 593-607. Clinical Trial No.: NCT02790957.

Hyperglycemia, Reduced Hematopoietic Stem Cells, and Outcome of COVID-19

Admission hyperglycemia has emerged worldwide as a predictor of poor coronavirus disease 2019 (COVID-19) outcome. Hyperglycemia leads to a defect in circulating hematopoietic stem/progenitor cells (HSPCs), which, in turn, predicts diabetic complications. Here, we explored whether reduced HSPCs mediated at least part of the prognostic effect of hyperglycemia on COVID-19 outcome. We found that patients with COVID-19 (n = 100) hospitalized in a nonintensive setting displayed dramatically (50-60%) reduced levels of HSPCs measured by flow cytometry as CD34+, CD34+CD45dim, or CD34+CD133+ cells, compared with control subjects (n = 595). This finding was highly significant (all P < 10-10) after multivariable adjustment, or manual 1:1 patient match, or propensity score matching. Admission hyperglycemia (≥7.0 mmol/L) was present in 45% of patients, was associated with a significant further ∼30% HSPCs reduction, and predicted a 2.6-fold increased risk of the primary outcome of adverse COVID-19 course (admittance to the intensive care unit or death). Low HSPCs were also associated with advanced age, higher peak C-reactive protein, and neutrophil-to-lymphocyte ratio. Independently from confounders, 1 SD lower CD34+ HSPCs was associated with a more than threefold higher risk of adverse outcome. Upon formal analysis, reduction of HSPCs was a significant mediator of the admission hyperglycemia on COVID-19 outcome, being responsible for 28% of its prognostic effect.

Type 1 Diabetes Patients With Different Residual Beta-Cell Function but Similar Age, HBA1c, and Cardiorespiratory Fitness Have Differing Exercise-Induced Angiogenic Cell Mobilisation

BACKGROUND

Many individuals with type 1 diabetes retain residual beta-cell function. Sustained endogenous insulin and C-peptide secretion is associated with reduced diabetes related complications, but underlying mechanisms remain unclear. Lower circulating numbers of endothelial and hematopoietic progenitor cells (EPCs and HPCs), and the inability to increase the count of these cells in response to exercise, are also associated with increased diabetes complications and cardiovascular disease. It is unknown whether residual beta-cell function influences HPCs and EPCs. Thus, this study examined the influence of residual beta-cell function in type 1 diabetes upon exercise-induced changes in haematopoietic (HPCs) and endothelial progenitor cells (EPCs).

METHODS

Participants with undetectable stimulated C-peptide (n=11; Cpep_und), 10 high C-peptide (Cpep_high; >200 pmol/L), and 11 non-diabetes controls took part in this observational exercise study, completing 45 minutes of intensive walking at 60% V˙O2peak . Clinically significant HPCs (CD34⁺) and EPCs (CD34⁺VEGFR2⁺) phenotypes for predicting future adverse cardiovascular outcomes, and subsequent cell surface expression of chemokine receptor 4 (CXCR4) and 7 (CXCR7), were enumerated at rest and immediately post-exercise by flow cytometry.

RESULTS

Exercise increased HPCs and EPCs phenotypes similarly in the Cpep_high and control groups (+34-121% across phenotypes, p<0.04); but Cpep_und group did not significantly increase from rest, even after controlling for diabetes duration. Strikingly, the post-exercise Cpep_und counts were still lower than Cpep_high at rest.

CONCLUSIONS

Residual beta-cell function is associated with an intact exercise-induced HPCs and EPCs mobilisation. As key characteristics (age, fitness, HbA1c) were similar between groups, the mechanisms underpinning the absent mobilisation within those with negative C-peptide, and the vascular implications, require further investigation.

Effects of Antidiabetic Drugs on Endothelial Function in Patients With Type 2 Diabetes Mellitus: A Bayesian Network Meta-Analysis

BACKGROUND

The changes of endothelial function in type 2 diabetes mellitus (T2DM) patients are closely associated with the development of cardiovascular disease (CVD). However, it is still unclear whether commonly used antidiabetic drugs can improve endothelial function. Flow-mediated dilation (FMD) is a noninvasive tool for evaluating endothelial function, which typically examines changes in the brachial artery diameter in response to ischemia using ultrasound. We performed a network meta-analysis (NMA) to explore the associations between changes in endothelial function and antidiabetic drugs by evaluating FMD in T2DM patients.

METHODS

We systematically searched several electronic databases for randomized controlled trials (RCTs) published from inception until January 25, 2022 with no language restriction. The primary outcome was FMD change in all studies, and we performed subgroup analysis in T2DM patients without CVD. NMA was performed to calculate the mean differences (MDs) with 95% confidence intervals (CIs).

RESULTS

From the 1,987 candidate articles identified in the initial search, 30 RCTs were eventually included in the analysis. In all studies, glucagon-like peptide-1 receptor (GLP-1R) agonists [MD = 3.70 (1.39-5.97)], TZD [MD = 1.96 (0.006-3.89)] produced improvement of FMD change compared to lifestyle intervention. GLP-1R agonists [MD = 3.33 (1.36-5.34) and MD = 3.30 (1.21-5.43)] showed significantly greater improvements in FMD change in pairwise comparisons with sulfonylureas and placebo. SGLT-2i also showed efficacy compared to sulfonylureas (MD = 1.89, 95% CI, 0.10, 3.75). In studies of T2DM patients without CVD, GLP-1R agonists [MD = 3.53 (1.24-5.76)], and TZD [MD = 2.30 (0.27-3.24)] produced improvements in FMD change compared to lifestyle treatment. GLP-1R agonists [MD = 3.25 (1.13-5.40), and MD = 3.85 (1.68-6.13)] showed significantly greater improvements in pairwise comparisons with sulfonylureas, and placebo.

CONCLUSION

In T2DM patients, both GLP-1R agonists, SGLT-2i and TZD have favorable effects to improve endothelial function in T2DM patients. In T2DM patients without CVD, GLP-1R agonists had a greater effect to improve endothelial function than sulfonylureas. These suggested that GLP-1R agonists are associated with significantly improved endothelial function in T2DM patients.

A Meta-Analysis of Randomized Controlled Trials on Therapeutic Efficacy and Safety of Autologous Cell Therapy for Atherosclerosis Obliterans

BACKGROUND

Atherosclerosis obliterans (ASO) is a chronic occlusive arterial disease and the most common type of peripheral arterial disease. Current treatment options like medication and vascularization have limited effects for "no-option" patients, and stem cell therapy is considered a viable option although its application and efficacy have not been standardized. The objective of this review was to assess the safety and efficacy of autologous stem cell therapy in patients with ASO.

METHODS

We performed a literature search of published RCTs for ASO patients receiving stem cell therapy without a revascularization option. PubMed, Embase, and the Cochrane Library were searched. This study was conducted by a pair of authors independently and audited by a third author. Data were synthesized with a random-effect model.

RESULTS

630 patients in 12 RCTs were included. The results showed that cell therapy significantly improved total amputation (RR: 0.64, p = 0.004, 95% CI: [0.47, 0.87]), major amputation (RR: 0.69, p = 0.02, 95% CI: [0.50, 0.94]), ankle-brachial index (ABI) (MD = 0.08, p = 0.004, 95% CI: [0.02, 0.13]), transcutaneous oxygen tension (TcO₂) (MD = 11.52, p = 0.004, 95% CI: [3.60, 19.43]) and rest pain score (MD = -0.64, p = 0.007, 95% CI: [-1.10, -0.17]) compared to placebo or standard care. However, current studies showed cell therapy was not superior to placebo or standard care in all-cause death (RR: 0.75, p = 0.34, 95% CI: [0.41, 1.36]) and ulcer size (MD = -8.85, p = 0.39, CI: [-29.05,11.36]).

LIMITATION

The number of trials included was limited. Moreover, most trials were designed for "no-option" patients and thus the results should be applied with caution to other PAD patients.

CONCLUSION

ASO patients can benefit from autologous cell therapy in limb salvage, limb blood perfusion, and rest pain alleviation.

Evaluation of Circulating Endothelial Progenitor Cells in Abdominal Aortic Aneurysms after Endovascular Aneurysm Repair

Background and Objectives

Circulating endothelial progenitor cells (EPCs) participate in vascular repair and predict cardiovascular outcomes. The aim of this study was to investigate the correlation between EPCs and abdominal aortic aneurysms (AAAs).

Methods and Results

Patients (age 67±9.41 years) suffering from AAAs (aortic diameters 58.09±11.24 mm) were prospectively enrolled in this study. All patients received endovascular aneurysm repair (EVAR). Blood samples were taken preoperatively and 14 days after surgery from patients with aortic aneurysms. Samples were also obtained from age-matched control subjects. Circulating EPCs were defined as those cells that were double positive for CD34 and CD309. Rat models of AAA formation were generated by the peri-adventitial elastase application of either saline solution (control; n=10), or porcine pancreatic elastase (PPE; n=14). The aortas were analyzed using an ultrasonic video system and immunohistochemistry. The levels of CD34^＋/CD309^＋ cells in the peripheral blood mononuclear cell populations were measured by flow cytometry. The baseline numbers of circulating EPCs (CD34^＋/CD309^＋) in the peripheral blood were significantly smaller in AAA patients compared with control subjects. The number of EPCs doubled by the 14th day after EVAR. A total of 78.57% of rats in the PPE group (11/14) formed AAAs (dilation ratio >150%). The numbers of EPCs from defined AAA rats were significantly decreased compared with the control group.

Conclusions

EPC levels may be useful for monitoring abdominal aorta aneurysms and rise after EVAR in patients with aortic aneurysms, and might contribute to the rapid endothelialization of vessels.

Endothelial Progenitor Cells Count after Acute Ischemic Stroke Predicts Functional Outcome in Patients with Carotid Atherosclerosis

OBJECTIVES

Circulating Endothelial Progenitor Cells (EPCs) predict cardiovascular outcomes in patients with coronary disease. However, the predictive value of EPCs after ischemic stroke is not well established. We aimed to study the prognostic role of EPCs in patients with acute ischemic stroke and carotid atherosclerosis, focusing on post-stroke functional outcome and stroke recurrences.

MATERIALS AND METHODS

We studied consecutive adult patients with an acute (<7 days) anterior circulation ischemic stroke and carotid atherosclerosis. Cardioembolic strokes were excluded. We measured circulating EPCs by flow cytometry (CD34+/CD133+/KDR+) at inclusion (7±1 days after stroke) and at one year of follow-up. At three months and at one year we registered the modified Rankin Scale score, stroke recurrences and coronary syndromes during the follow-up.

RESULTS

We studied 80 patients with a mean age of 74.3±10.4 years. We divided the population in tertiles according to the EPCs count. At three months we observed a favorable outcome in 25/36 (69.4%) patients in the lowest, 19/22 (86.4%) in the medium and 21/22 (95.5%) in the highest tercile (p=0.037). In the multivariable analysis a higher EPCs count was associated with favorable functional outcome after adjusting for age and baseline NIHSS score (OR=3.61, 95%CI 1.34-9.76; p=0.011). This association persisted at one year of follow-up. We did not find association between counts of EPCs and stroke recurrence.

CONCLUSIONS

In patients with acute ischemic stroke and carotid atherosclerosis, a higher count of EPCs was associated with favorable functional outcome in the mid and long-term follow-up. Counts of EPCs did not predict stroke recurrences.

Elevated Circulating Stem Cells Level is Observed One Month After Implantation of Carmat Bioprosthetic Total Artificial Heart

The Aeson® total artificial heart (A-TAH) has been developed as a total heart replacement for patients at risk of death from biventricular failure. We previously described endothelialization of the hybrid membrane inside A-TAH probably at the origin of acquired hemocompatibility. We aimed to quantify vasculogenic stem cells in peripheral blood of patients with long-term A-TAH implantation. Four male adult patients were included in this study. Peripheral blood mononuclear cells were collected before A-TAH implantation (T0) and after implantation at one month (T1), between two and five months (T2), and then between six and twelve months (T3). Supervised analysis of flow cytometry data confirmed the presence of the previously identified Lin^-CD133⁺CD45^- and Lin^-CD34⁺ with different CD45 level intensities. Lin^-CD133⁺CD45^-, Lin^-CD34⁺CD45^- and Lin^-CD34⁺CD45⁺ were not modulated after A-TAH implantation. However, we demonstrated a significant mobilization of Lin^-CD34⁺CD45^dim (p = 0.01) one month after A-TAH implantation regardless of the expression of CD133 or c-Kit. We then visualized data for the resulting clusters on a uniform manifold approximation and projection (UMAP) plot showing all single cells of the live Lin^- and CD34⁺ events selected from down sampled files concatenated at T0 and T1. The three clusters upregulated at T1 are CD45^dim clusters, confirming our results. In conclusion, using a flow cytometry approach, we demonstrated in A-TAH-transplanted patients a significant mobilization of Lin^-CD34⁺CD45^dim in peripheral blood one month after A-TAH implantation. Using a flow cytometry approach, we demonstrated in A-TAH transplanted patients a significant mobilization of Lin^-CD34⁺CD45^dim in peripheral blood one month after A-TAH implantation. This cell population could be at the origin of newly formed endothelial cells on top of hybrid membrane in Carmat bioprosthetic total artificial heart.

Endothelial Progenitor Cells Modulate the Phenotype of Smooth Muscle Cells and Increase Their Neointimal Accumulation Following Vascular Injury

BACKGROUND

 Smooth muscle cells (SMCs) are the main driver of neointima formation and restenosis following vascular injury. In animal models, endothelial progenitor cells (EPCs) accelerate endothelial regeneration and reduce neointima formation after arterial injury; however, EPC-capture stents do not reduce target vessel failure compared with conventional stents. Here we examined the influence of EPCs on features of SMCs pivotal for their impact on injury-induced neointima formation including proliferation, migration, and phenotype switch.

METHODS AND RESULTS

 EPCs, their conditioned medium, and EPC-derived microparticles induced proliferation of SMCs while limiting their apoptosis. In transwell membrane experiments and scratch assays, EPCs stimulated migration of SMCs and accelerated their recovery from scratch-induced injury. Treatment of SMCs with an EPC-derived conditioned medium or microparticles triggered transformation of SMCs toward a synthetic phenotype. However, co-cultivation of EPCs and SMCs enabling direct cell-cell contacts preserved their original phenotype and protected from the transformative effect of SMC cholesterol loading. Adhesion of EPCs to SMCs was stimulated by SMC injury and reduced by blocking CXCR2 and CCR5. Interaction of EPCs with SMCs modulated their secretory products and synergistically increased the release of selected chemokines. Following carotid wire injury in athymic mice, injection of EPCs resulted not only in reduced neointima formation but also in altered cellular composition of the neointima with augmented accumulation of SMCs.

CONCLUSION

 EPCs stimulate proliferation and migration of SMCs and increase their neointimal accumulation following vascular injury. Furthermore, EPCs context-dependently modify the SMC phenotype with protection from the transformative effect of cholesterol when a direct cell-cell contact is established.