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McIntyre CW. Update on Hemodialysis-Induced Multiorgan Ischemia: Brains and Beyond. J Am Soc Nephrol 2024; 35:653-664. [PMID: 38273436 PMCID: PMC11149050 DOI: 10.1681/asn.0000000000000299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 12/17/2023] [Indexed: 01/27/2024] Open
Abstract
Hemodialysis is a life-saving treatment for patients with kidney failure. However, patients requiring hemodialysis have a 10-20 times higher risk of cardiovascular morbidity and mortality than that of the general population. Patients encounter complications such as episodic intradialytic hypotension, abnormal perfusion to critical organs (heart, brain, liver, and kidney), and damage to vulnerable vascular beds. Recurrent conventional hemodialysis exposes patients to multiple episodes of circulatory stress, exacerbating and being aggravated by microvascular endothelial dysfunction. This promulgates progressive injury that leads to irreversible multiorgan injury and the well-documented higher incidence of cardiovascular disease and premature death. This review aims to examine the underlying pathophysiology of hemodialysis-related vascular injury and consider a range of therapeutic approaches to improving outcomes set within this evolved rubric..
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Affiliation(s)
- Christopher W McIntyre
- Lilibeth Caberto Kidney Clinical Research Unit, Lawson Health Research Institute, London, Ontario, Canada, and Departments of Medicine, Medical Biophysics and Pediatrics, Western University, London, Ontario, Canada
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Xia Y, Liang C, Kang J, You K, Xiong Y. Obstructive Sleep Apnea and Obesity Are Associated with Hypertension in a Particular Pattern: A Retrospective Study. Healthcare (Basel) 2023; 11:healthcare11030402. [PMID: 36766978 PMCID: PMC9913941 DOI: 10.3390/healthcare11030402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/21/2023] [Accepted: 01/28/2023] [Indexed: 02/04/2023] Open
Abstract
Obstructive sleep apnea (OSA) and obesity can increase the risk of hypertension, but the combined effects of these two conditions on hypertension are not yet known. We collected the basic characteristics, sleep parameters, and glucose levels of subjects with a polysomnography test and divided them into four groups, according to whether they had severe OSA and obesity or not. The main effects of severe OSA and obesity and the interactions of the two on systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels were detected using analysis of covariance. The association between obesity and severe OSA and abnormal blood pressure and their combined effects were detected with logistic regression. In total, 686 subjects were included. After adjusting for multiple confounding factors, the strong main effects of obesity and severe OSA were detected in the SBP and DBP levels, with no combined effects from the two conditions on SBP or DBP. Obesity was independently associated with the presence of hyper-systolic blood pressure (hyper-SBP) and hypertension, and severe OSA was independently associated with the presence of hyper diastolic blood pressure (hyper-DBP) and hypertension. No effects of the interaction between severe OSA and obesity on the presence of abnormal blood pressure were observed. Both severe OSA and obesity were associated with hypertension, while obesity was closely associated with hyper-SBP, and severe OSA was associated with hyper-DBP. No effects of the interaction between these two on hypertension were observed.
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Affiliation(s)
- Yunyan Xia
- Department of Otorhinolaryngology–Head and Neck Surgery, First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Caihong Liang
- Department of Otorhinolaryngology–Head and Neck Surgery, First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Junxin Kang
- Department of Otorhinolaryngology–Head and Neck Surgery, First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Kai You
- Department of Anesthesiology, First Affiliated Hospital of Nanchang University, Nanchang 330006, China
- Correspondence: (K.Y.); (Y.X.)
| | - Yuanping Xiong
- Department of Otorhinolaryngology–Head and Neck Surgery, First Affiliated Hospital of Nanchang University, Nanchang 330006, China
- Correspondence: (K.Y.); (Y.X.)
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3
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Janssen BGH, Zhang YM, Kosik I, Akbari A, McIntyre CW. Intravital microscopic observation of the microvasculature during hemodialysis in healthy rats. Sci Rep 2022; 12:191. [PMID: 34996931 PMCID: PMC8741960 DOI: 10.1038/s41598-021-03681-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 12/08/2021] [Indexed: 11/09/2022] Open
Abstract
Hemodialysis (HD) provides life-saving treatment for kidney failure. Patient mortality is extremely high, with cardiovascular disease (CVD) being the leading cause of death. This results from both a high underlying burden of cardiovascular disease, as well as additional physiological stress from the HD procedure itself. Clinical observations indicate that HD is associated with microvascular dysfunction (MD), underlining the need for a fundamental pathophysiological assessment of the microcirculatory consequences of HD. We therefore successfully developed an experimental small animal model, that allows for a simultaneous real-time assessment of the microvasculature. Using in-house built ultra-low surface area dialyzers and miniaturized extracorporeal circuit, we successfully dialyzed male Wistar Kyoto rats and combined this with a simultaneous intravital microscopic observation of the EDL microvasculature. Our results show that even in healthy animals, a euvolemic HD procedure can induce a significant systemic hemodynamic disturbance and induce disruption of microvascular perfusion (as evidence by a reduction in the proportion of the observed microcirculation receiving blood flow). This study, using a new small animal hemodialysis model, has allowed direct demonstration that microvascular blood flow in tissue in skeletal muscle is acutely reduced during HD, potentially in concert with other microvascular beds. It shows that preclinical small animal models can be used to further investigate HD-induced ischemic organ injury and allow rapid throughput of putative interventions directed at reducing HD-induced multi-organ ischemic injury.
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Affiliation(s)
- B G H Janssen
- Department of Medical Biophysics, Western University, London, ON, Canada.
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada.
- Kidney Clinical Research Unit (KCRU), London Health Sciences Centre, 800 Commissioners Rd. East, London, ON, N6C 6B5, Canada.
| | - Y M Zhang
- Department of Medical Biophysics, Western University, London, ON, Canada
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada
- Trauma Research Centre, Fourth Medical Center of the Chinese PLA General Hospital, Beijing, 100048, People's Republic of China
- Intensive Care Unit, Tianjin Nankai Hospital, Tianjin, 300100, People's Republic of China
| | - I Kosik
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada
- Imaging Program, Lawson Health Research Institute, St. Joseph's Health Care, London, ON, Canada
| | - A Akbari
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada
- Robarts Research Institute, Western University, London, ON, Canada
| | - C W McIntyre
- Department of Medical Biophysics, Western University, London, ON, Canada
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada
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Janssen BGH, Najiminaini M, Zhang YM, Omidi P, Carson JJL. Multispectral intravital microscopy for simultaneous bright-field and fluorescence imaging of the microvasculature. Appl Microsc 2021; 51:12. [PMID: 34302534 PMCID: PMC8310548 DOI: 10.1186/s42649-021-00059-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 06/08/2021] [Indexed: 12/05/2022] Open
Abstract
Intravital video microscopy permits the observation of microcirculatory blood flow. This often requires fluorescent probes to visualize structures and dynamic processes that cannot be observed with conventional bright-field microscopy. Conventional light microscopes do not allow for simultaneous bright-field and fluorescent imaging. Moreover, in conventional microscopes, only one type of fluorescent label can be observed. This study introduces multispectral intravital video microscopy, which combines bright-field and fluorescence microscopy in a standard light microscope. The technique enables simultaneous real-time observation of fluorescently-labeled structures in relation to their direct physical surroundings. The advancement provides context for the orientation, movement, and function of labeled structures in the microcirculation.
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Affiliation(s)
- Barry G H Janssen
- Department of Medical Biophysics, Western University, London, ON, N6A 5C1, Canada. .,Kidney Clinical Research Unit (KCRU), London Health Sciences Centre, London, ON, N6C 6B5, Canada.
| | - Mohamadreza Najiminaini
- Imaging Program, St.Joseph's Health Care, Lawson Health Research Institute, London, ON, N6A 4V2, Canada.,Department of Pathology, Western University, London, ON, N6A 5C1, Canada
| | - Yan Min Zhang
- Kidney Clinical Research Unit (KCRU), London Health Sciences Centre, London, ON, N6C 6B5, Canada.,Trauma Research Centre, Fourth Medical Center of the Chinese PLA General Hospital, Beijing, 100048, People's Republic of China.,School of Biomedical Engineering, Western University, London, ON, N6A 3K7, Canada.,Intensive Care Unit, Tianjin Nankai Hospital, Tianjin, 300100, People's Republic of China
| | - Parsa Omidi
- Imaging Program, St.Joseph's Health Care, Lawson Health Research Institute, London, ON, N6A 4V2, Canada.,Department of Pathology, Western University, London, ON, N6A 5C1, Canada.,Intensive Care Unit, Tianjin Nankai Hospital, Tianjin, 300100, People's Republic of China
| | - Jeffrey J L Carson
- Department of Medical Biophysics, Western University, London, ON, N6A 5C1, Canada.,Imaging Program, St.Joseph's Health Care, Lawson Health Research Institute, London, ON, N6A 4V2, Canada.,Department of Pathology, Western University, London, ON, N6A 5C1, Canada.,Intensive Care Unit, Tianjin Nankai Hospital, Tianjin, 300100, People's Republic of China
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Mahmoud O, El-Sakka M, Janssen BGH. Two-step machine learning method for the rapid analysis of microvascular flow in intravital video microscopy. Sci Rep 2021; 11:10047. [PMID: 33976293 PMCID: PMC8113514 DOI: 10.1038/s41598-021-89469-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 04/23/2021] [Indexed: 11/29/2022] Open
Abstract
Microvascular blood flow is crucial for tissue and organ function and is often severely affected by diseases. Therefore, investigating the microvasculature under different pathological circumstances is essential to understand the role of the microcirculation in health and sickness. Microvascular blood flow is generally investigated with Intravital Video Microscopy (IVM), and the captured images are stored on a computer for later off-line analysis. The analysis of these images is a manual and challenging process, evaluating experiments very time consuming and susceptible to human error. Since more advanced digital cameras are used in IVM, the experimental data volume will also increase significantly. This study presents a new two-step image processing algorithm that uses a trained Convolutional Neural Network (CNN) to functionally analyze IVM microscopic images without the need for manual analysis. While the first step uses a modified vessel segmentation algorithm to extract the location of vessel-like structures, the second step uses a 3D-CNN to assess whether the vessel-like structures have blood flowing in it or not. We demonstrate that our two-step algorithm can efficiently analyze IVM image data with high accuracy (83%). To our knowledge, this is the first application of machine learning for the functional analysis of microvascular blood flow in vivo.
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Affiliation(s)
- Ossama Mahmoud
- Department of Computer Sciences, Western University, London, ON, N6A 3K7, Canada
| | - Mahmoud El-Sakka
- Department of Computer Sciences, Western University, London, ON, N6A 3K7, Canada
| | - Barry G H Janssen
- Department of Medical Biophysics, Western University, London, ON, N6A 3K7, Canada.
- Centre for Critical Illness Research (CCIR), Lawson Health Research Institute, London, ON, N6C 6B5, Canada.
- Kidney Clinical Research Unit (KCRU), Lawson Health Research Institute, London, ON, N6C 6B5, Canada.
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Arslan NG, Pancar GS. Nailfold capillaroscopic changes of sleep apnea patients. Microvasc Res 2021; 137:104177. [PMID: 33984340 DOI: 10.1016/j.mvr.2021.104177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/01/2021] [Accepted: 05/06/2021] [Indexed: 11/25/2022]
Abstract
BACKGROUND Obstructive Sleep Apnea Syndrome (OSAS) have frequent association with comorbidities and this makes it an independent risk factor for cardiovascular disease. Not only endothelial dysfunction, but also arterial stiffening, increased inflammatory mediators, oxidative stress after hypoxemia that develops due to OSAS, cause vascular pathologies in all diameters of vessels. Nail bed capillaroscopy is a simple, noninvasive, useful method to examine microcirculation and evaluate nail bed capillary abnormalities in diseases that cause vascular damage. The aim of this study is to examine microvascular changes in the nail bed of OSAS patients by capillaroscopy. METHODS 59 OSAS patients and 60 healthy cases (totally 119) were included. One single attended polysomnography was applied with Embla N7000 series (RemLogic Eastmed, Natus); and apnea-hypopnea index (AHI), oxygen de-saturation index >4% (ODI4%), minimum oxygen saturation (SaO2 Min.), total duration of oxygen desaturation, comorbidities, body mass index (BMI), smoking habit, sleep questionnaire applications were analyzed. Nailfold capillaroscopy was performed using a digital dermoscope (Molemax II, X30) and all images were evaluated for capillary density, capillary loop enlargement, capillary tortuosity, branching vessels, micro hemorrhages, avascular areas and splinter hemorrhages. RESULTS The prevalence rates of all capillaroscopy findings were significantly higher in the patient group (p < 0.05). There was an inverse and moderate relationship between AHI and mean saturation (p < 0.05). A statistically significant correlation was detected between the presence of hypertension (HT) and the severity of capillary tortuosity (CT) (p = 0.002), avascular area (AA) (p = 0.004), and periungual cyanosis (PUC) (p = 0.042); also between smoking habit and intensity of capillary dilatation, enlargement dilatation-enlarged giant capillaries (CELON) (p = 0.004), CT (p = 0.018) findings. Capillary distribution (CD), CELON, CT and AA findings were significantly higher in the group with low mean saturation (p < 0.05). DM was found to be significantly higher in individuals with high Epworth Sleep Scale (ESS) (p = 0.035). CONCLUSION In this study; 1) the nail bed capillaroscopy was used to examine vascular damage in OSAS, and 2) irregularities detected in the distal nail bed specific to a disease have been mentioned for the first time. It has been shown that endothelial damage is particularly related to the severity of hypoxia. HT and smoking history causes endothelial damage independent of the severity of the disease and hypoxia. Also, ESS may be more determinant in the screening of sleep disorders in diabetic patients.
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Affiliation(s)
- Nevra Gullu Arslan
- Samsun Educational and Research Hospital, Department of Pulmonology, TR-55000 Samsun, Turkey.
| | - Gunseli Sefika Pancar
- Samsun Education and Research Hospital, Department of Dermatology, TR-55000 İlkadim, Samsun, Turkey
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Brożyna-Tkaczyk K, Myśliński W, Mosiewicz J. The Assessment of Endothelial Dysfunction among OSA Patients after CPAP Treatment. Medicina (B Aires) 2021; 57:medicina57040310. [PMID: 33806108 PMCID: PMC8064446 DOI: 10.3390/medicina57040310] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 11/21/2022] Open
Abstract
Background and Objectives: Microcirculation dysfunction is present in patients with obstructive sleep apnea (OSA). Intermittent hypoxia generates “oxidative stress”, which contributes to chronic inflammation. The secretion of nitric oxide (NO), which is responsible for adequate regulation of the endothelium, is impaired due to a decrease in endothelial nitric oxide synthetase (eNOS) expression and an increase in endogenous eNOS inhibitors. Furthermore, nocturnal awakenings lead to the dysregulation of cortisol release and increased stimulation of the sympathetic nervous system. The non-invasive method of choice in OSA treatment is continuous positive airway pressure (CPAP). Materials and Methods: PubMed, Scopus, and Google Scholar databases were searched, and only papers published in the last 15 years were subsequently analyzed. For this purpose, we searched for keywords in article titles or contents such as “obstructive sleep apnea”, “microcirculation”, and “CPAP”. In our review, we only studied English articles that reported systemic reviews and meta-analyses, clinical studies, and case reports. Results: Endothelial dysfunction can be assessed by methods based on reactive hyperemia, such as flow-mediated dilation (FMD) measured by ultrasonography, laser-Doppler flowmetry (LDF), or capillaroscopy. In invasive techniques, intravenous administration of vasodilator substances takes place. Some surveys detected impaired microcirculation in OSA patients compared with healthy individuals. The level of dysfunction depended on the severity of OSA. CPAP treatment significantly improved endothelial function and microvascular blood flow and lowered the inflammatory mediator level. Conclusions: The first-choice treatment—CPAP—reduces the number of apneas and hypopneas during the night, induces the reversal of hypopnea and the chronic inflammatory state, and enhances activation of the sympathetic nervous system. Changes are visible as improved blood flow in both macro- and microcirculation, increased arterial elasticity, and decreased stiffness. Thus, early implementation of adequate treatment could be essential to reduce high cardiovascular risk in patients with OSA.
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