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A meta-analysis of variability in conjunctival microvascular hemorheology metrics. Microvasc Res 2022; 142:104340. [DOI: 10.1016/j.mvr.2022.104340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 12/28/2022]
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Samarron SL, Miller JW, Cheung AT, Chen PC, Lin X, Zwerdling T, Wun T, Green R. Homocysteine is associated with severity of microvasculopathy in sickle cell disease patients. Br J Haematol 2020; 190:450-457. [PMID: 32307711 DOI: 10.1111/bjh.16618] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 03/03/2020] [Accepted: 03/06/2020] [Indexed: 12/31/2022]
Abstract
The pathophysiology of sickle cell disease (SCD) includes vasculopathy as well as anaemia. Elevated plasma homocysteine is a risk factor for vascular disease and may be associated with increased risk of vascular complications in SCD patients. In the present study, microvascular characteristics were assessed in the bulbar conjunctiva of 18 paediatric and 18 adult SCD patients, using the non-invasive technique of computer-assisted intravital microscopy. A vasculopathy severity index (SI) was computed to quantify the degree of microvasculopathy in each patient. Plasma homocysteine and several of its determinants [serum folate and vitamin B12, plasma pyridoxal-5'-phosphate (vitamin B6 status) and creatinine (kidney function)] were measured. Age was strongly correlated with microvasculopathy in the SCD patients, with the SI increasing about 0·1 unit per one-year increase in age (P < 0·001). After adjusting for age, gender, B-vitamin status and creatinine, homocysteine concentration was directly correlated with severity index (P < 0·05). Age and homocysteine concentration were independent predictors of microvasculopathy in SCD patients. It remains to be determined whether lowering homocysteine concentrations using appropriate B-vitamin supplements (folate and vitamins B12 and B6) - particularly if started early in life - could ameliorate microvasculopathy and its associated complications in SCD patients.
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Affiliation(s)
- Sandra L Samarron
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA
| | - Joshua W Miller
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Anthony T Cheung
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA.,Institute for Biomedical Sciences, San Diego, CA, USA
| | - Peter C Chen
- Institute for Biomedical Sciences, San Diego, CA, USA.,Shiley Center for Orthopaedic Research and Education, La Jolla, CA, USA
| | - Xin Lin
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA
| | - Theodore Zwerdling
- Department of Pediatrics (Hematology-Oncology), University of California, Davis, CA, USA
| | - Ted Wun
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA.,Department of Internal Medicine (Hematology-Oncology), University of California, Davis, CA, USA.,UC Davis Clinical and Translational Science Center, Sacramento, CA, USA
| | - Ralph Green
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA.,Department of Internal Medicine (Hematology-Oncology), University of California, Davis, CA, USA
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Shu X, Wang J, Hu L. A review of functional slit lamp biomicroscopy. EYE AND VISION 2019; 6:15. [PMID: 31139665 PMCID: PMC6528339 DOI: 10.1186/s40662-019-0140-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 04/16/2019] [Indexed: 12/24/2022]
Abstract
Functional slit lamp biomicroscopy (FSLB) is a novel device which consists of a traditional slit-lamp and a digital camera. It can quantitatively assess vessel diameter, blood flow velocity, and blood flow rate and can create noninvasive microvascular perfusion maps (nMPMs). At present, FSLB is mainly used in contact lens (CL) and dry eye disease (DED) studies to advance our understanding of ocular surface microcirculation. FSLB-derived blood flow and vessel density measures are significantly altered in CL wearers and DED patients compared to normal people. These subtle changes in the ocular surface microcirculation may contribute to the monitoring of potential diseases of the body and provide a new way to diagnose dry eye disease. Therefore, this may also indicate that FSLB can be more widely applied in the study of other diseases to reveal the relationship between changes in ocular surface microcirculation and systemic diseases. The purpose of this paper is to summarize the functions of FSLB and the related studies especially in CL and DED.
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Affiliation(s)
- Xupeng Shu
- 1School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, 325027 China
| | - Jianhua Wang
- 2Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA
| | - Liang Hu
- 1School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, 325027 China
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Koutsiaris AG. Correlation of axial blood velocity to venular and arteriolar diameter in the human eye in vivo. Clin Hemorheol Microcirc 2016; 61:429-38. [PMID: 25267455 DOI: 10.3233/ch-141888] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The axial blood velocity (Vax) association with microvessel diameter (D) was studied at 104 different postcapillary venules (4 μm < D < 24 μm) and 30 different precapillary arterioles (6 μm≤D≤12 μm) in the human conjunctiva of normal healthy humans. Venular diameter sizes were classified as "very small" (Group 1, 4.4 μm≤D < 8.9 μm), "small" (Group 2, 8.9 μm≤D < 13.8 μm), "medium" (Group 3, 13.8 μm≤D < 19.1 μm) and "large" (Group 4, 19.1 μm≤D≤23.5). The Spearman's correlation coefficient (rs) in all 4 venular groups was less than 0.36 and not statistically significant (n = 26, p≥0.08). Similar correlation results were observed for the arteriolar group (rs) ≈ 0) for the peak systolic, the average and the end systolic axial velocities. Vax was significantly (p < 0.001) lower in Group 1 in comparison to that in Group 2 and significantly (p < 0.01) lower in Group 2 in comparison to that in Group 3. However, Vax was not significantly lower in Group 3 in comparison to that in Group 4. Average Vax and standard deviation was 0.48 ± 0.13, 0.64 ± 0.16, 0.82 ± 0.25 and 0.88 ± 0.32 mm/s for Groups 1, 2, 3 and 4 respectively. The above results reinforce the importance of measuring D in microvascular hemodynamics. Higher diameters suggest higher axial velocities but Vax does not change significantly within the limits of each of the aforementioned groups.
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Vessel Sampling and Blood Flow Velocity Distribution With Vessel Diameter for Characterizing the Human Bulbar Conjunctival Microvasculature. Eye Contact Lens 2016; 42:135-40. [PMID: 25839347 DOI: 10.1097/icl.0000000000000146] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE This study determined (1) how many vessels (i.e., the vessel sampling) are needed to reliably characterize the bulbar conjunctival microvasculature and (2) if characteristic information can be obtained from the distribution histogram of the blood flow velocity and vessel diameter. METHODS Functional slitlamp biomicroscope was used to image hundreds of venules per subject. The bulbar conjunctiva in five healthy human subjects was imaged on six different locations in the temporal bulbar conjunctiva. The histograms of the diameter and velocity were plotted to examine whether the distribution was normal. Standard errors were calculated from the standard deviation and vessel sample size. The ratio of the standard error of the mean over the population mean was used to determine the sample size cutoff. The velocity was plotted as a function of the vessel diameter to display the distribution of the diameter and velocity. RESULTS The results showed that the sampling size was approximately 15 vessels, which generated a standard error equivalent to 15% of the population mean from the total vessel population. The distributions of the diameter and velocity were not only unimodal, but also somewhat positively skewed and not normal. The blood flow velocity was related to the vessel diameter (r=0.23, P<0.05). CONCLUSIONS This was the first study to determine the sampling size of the vessels and the distribution histogram of the blood flow velocity and vessel diameter, which may lead to a better understanding of the human microvascular system of the bulbar conjunctiva.
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Abstract
Both adult and pediatric patients with sickle cell disease face a higher risk of stroke than the general population. Given the different underlying pathophysiology predisposing these patients to stroke, providers should be aware of differences in guidelines for stroke management. This paper reviews diagnostic considerations and recommendations during the evaluation and acute management of patients with sickle cell disease presenting with stroke, focusing on recent updates in the literature. Given the high recurrence rate of stroke in these patients, secondary prevention and curative measures will also be reviewed.
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Daniel MJ, Muddegowda PH, Chezhiansubash, Lingegowda JB, Gopal N, Prasad K. Study of Twenty One Cases of Red Cell Exchange in a Tertiary Care Hospital in Southern India. J Clin Diagn Res 2016; 10:EC28-30. [PMID: 27437227 DOI: 10.7860/jcdr/2016/13427.7809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 02/24/2016] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Red Cell Exchange (RCE) is removal of a patient's red blood cells while replacing with donor red blood cells either manually or using automated systems. RCE is beneficial in patients with Sickle Cell Disease (SCD) either during sickling crisis or prior to major surgical procedures to bring down the sickling percentage as high sickling percentage during prolonged anaesthesia may lead to vaso-occlusive crisis. It is also employed in patients infested with malaria and babesiosis where parasitic index remain high despite medical management. RCE is also tried as an adjuvant therapy in certain poisons like nitrobenzene and carbon monoxide when first line management fails. AIM To study the effectiveness, clinical outcome, challenges and complications of RCE in various clinical scenario and to understand how this procedure can be effectively utilized in the management of patients in Indian scenario. MATERIALS AND METHODS This retro prospective study was conducted in tertiary care center in southern India which analyzed 21 RCE procedures performed on patients with different clinical conditions. Of the 21 RCE performed, 18 procedures were performed on patients with case of sickle cell disease, Two procedures were performed on patients infested with severe falciparum malaria and one procedure was performed on a patient with nitrobenzene poisoning. All procedures were performed using Spectra Optia(®) Apheresis System - Terumo BCT. RESULTS All the 18 patients who underwent the RCE for sickle cell anaemia were admitted for hemi-arthroplasty for avascular necrosis of the head of femur. The average initial HbS levels were between 73-85% and post RCE it was brought down to 22-29% and was achieved in a single sitting in all the cases. Among the two patients infested with severe falciparum malaria, RCE helped in reducing the infestation rate. In case of nitrobenzene poisoning, RCE helped in improvement of oxygen saturation and patient showed significant improvement. CONCLUSION RCE is an safe and clinically effective therapeutic modality with very minimal to nil side effects. RCE is possibly underutilized therapy in developing world like India due to various reasons like inadequate awareness/ technical expertise, lack of equipments and facilities to identify the clinical conditions per se etc.
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Affiliation(s)
- M Joshua Daniel
- Associate Professor, Department of Transfusion Medicine, Mahatma Gandhi Medical College and Research Institute , SBV, Pillaiyarkuppam, Puducherry, India
| | - Prakash H Muddegowda
- Associate Professor, Department of Pathology, VMKV Medical College , Seeragapadi, Salem, Tamil Nadu, India
| | - Chezhiansubash
- Consultant Hematologist, MIOT International Hospital , Chennai, India
| | - Jyothi B Lingegowda
- Associate Professor, Department of Pathology, VMKV Medical College , Seeragapadi, Salem, Tamil Nadu, India
| | - Niranjan Gopal
- Associate Professor, Department of Biochemistry, Mahatma Gandhi Medical College and Research Institute , SBV, Pillaiyarkuppam, Puducherry, India
| | - Krishna Prasad
- Lt col- Graded Specialist Anesthesia, AMC , 425 FD Hospital, Poonch
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John-Olabode S, Awodele I, Oni O. Adolescents with sickle cell anaemia: Experience in a private tertiary hospital serving a tertiary institution. Niger Med J 2015; 56:204-7. [PMID: 26229230 PMCID: PMC4518338 DOI: 10.4103/0300-1652.160397] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Many adolescents with sickle cell disease (SCD) have adjustment difficulties in the transition period from paediatric care to the adult system because they find themselves in unfamiliar waters where they have to learn to manage themselves. The aim of this study is to evaluate the prevalent crises and morbidities associated with SCD in adolescents in Babcock University Teaching Hospital (BUTH), to also assess the level of knowledge of these adolescents about SCD and to determine their emotional response to the disease. MATERIALS AND METHODS This was a retrospective review of case notes of adolescents with sickle cell anaemia that were seen in BUTH, from May 2013 to April 2014. Data extracted from the case notes was entered into a Microsoft (MS) Excel and analysed using descriptive statistics. Results were presented in tables. RESULTS A total of 50 subjects were seen in the department during this study period. Vaso-occlusive crises in the form of bone pains (93.1%) were the commonest crises encountered. Associated morbidities were malaria 34 (85%), tonsilitis 1 (2.5%), pneumonia 1 (2.5%), leg ulcer 1 (2.5%), azotaemia 1 (2.5%) and subarachnoid haemorrhage 2 (5%). Majority (88%) had adequate knowledge about general health maintenance while knowledge on nutrition and appropriate analgesia use is still inadequate. Eleven (22%) had symptoms of depression, four (8%) had suicidal ideation while one (2%) had a history of attempted suicide. CONCLUSION This study emphasizes the importance of psychosocial intervention as part of a comprehensive health management for people with SCD.
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Affiliation(s)
- Sarah John-Olabode
- Department of Haematology, Ben Carson School of Medicine, Babcock University, Ogun, Nigeria
| | - Ibironke Awodele
- Department of Haematology, Ben Carson School of Medicine, Babcock University, Ogun, Nigeria
| | - Omolade Oni
- Department of Haematology, Ben Carson School of Medicine, Babcock University, Ogun, Nigeria
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Wun T, Styles L, DeCastro L, Telen MJ, Kuypers F, Cheung A, Kramer W, Flanner H, Rhee S, Magnani JL, Thackray H. Phase 1 study of the E-selectin inhibitor GMI 1070 in patients with sickle cell anemia. PLoS One 2014; 9:e101301. [PMID: 24988449 PMCID: PMC4079300 DOI: 10.1371/journal.pone.0101301] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 06/03/2014] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Sickle cell anemia is an inherited disorder of hemoglobin that leads to a variety of acute and chronic complications. Abnormal cellular adhesion, mediated in part by selectins, has been implicated in the pathophysiology of the vaso-occlusion seen in sickle cell anemia, and selectin inhibition was able to restore blood flow in a mouse model of sickle cell disease. METHODS We performed a Phase 1 study of the selectin inhibitor GMI 1070 in patients with sickle cell anemia. Fifteen patients who were clinically stable received GMI 1070 in two infusions. RESULTS The drug was well tolerated without significant adverse events. There was a modest increase in total peripheral white blood cell count without clinical symptoms. Plasma concentrations were well-described by a two-compartment model with an elimination T1/2 of 7.7 hours and CLr of 19.6 mL/hour/kg. Computer-assisted intravital microscopy showed transient increases in red blood cell velocity in 3 of the 4 patients studied. CONCLUSIONS GMI 1070 was safe in stable patients with sickle cell anemia, and there was suggestion of increased blood flow in a subset of patients. At some time points between 4 and 48 hours after treatment with GMI 1070, there were significant decreases in biomarkers of endothelial activation (sE-selectin, sP-selectin, sICAM), leukocyte activation (MAC-1, LFA-1, PM aggregates) and the coagulation cascade (tissue factor, thrombin-antithrombin complexes). Development of GMI 1070 for the treatment of acute vaso-occlusive crisis is ongoing. TRIAL REGISTRATION ClinicalTrials.gov NCT00911495.
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Affiliation(s)
- Ted Wun
- Division of Hematology Oncology, University of California Davis School of Medicine, Sacramento, California, United States of America
- Clinical and Translational Sciences Center, UC Davis School of Medicine, Sacramento, California, United States of America
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California, United States of America
- VA Northern California Health Care System, Sacramento, California, United States of America
- * E-mail:
| | - Lori Styles
- Children's Hospital and Research Institute Oakland, Oakland, California, United States of America
| | - Laura DeCastro
- Division of Hematology and Oncology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Marilyn J. Telen
- Division of Hematology and Oncology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Frans Kuypers
- Children's Hospital and Research Institute Oakland, Oakland, California, United States of America
| | - Anthony Cheung
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California, United States of America
| | - William Kramer
- Kramer Consulting LLC, North Potomac, Maryland, United States of America
| | - Henry Flanner
- GlycoMimetics, Inc, Gaithersburg, Maryland, United States of America
| | - Seungshin Rhee
- Rho, Inc., Chapel Hill, North Carolina, United States of America
| | - John L. Magnani
- GlycoMimetics, Inc, Gaithersburg, Maryland, United States of America
| | - Helen Thackray
- GlycoMimetics, Inc, Gaithersburg, Maryland, United States of America
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Wanek J, Gaynes B, Lim JI, Molokie R, Shahidi M. Human bulbar conjunctival hemodynamics in hemoglobin SS and SC disease. Am J Hematol 2013; 88:661-4. [PMID: 23657867 DOI: 10.1002/ajh.23475] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/22/2013] [Accepted: 04/29/2013] [Indexed: 12/27/2022]
Abstract
The known biophysical variations of hemoglobin (Hb) S and Hb C may result in hemodynamic differences between subjects with SS and SC disease. The purpose of this study was to measure and compare conjunctival hemodynamics between subjects with Hb SS and SC hemoglobinopathies. Image sequences of the conjunctival microcirculation were acquired in 9 healthy control subjects (Hb AA), 24 subjects with SC disease, and 18 subjects with SS disease, using a prototype imaging system. Diameter (D) and blood velocity (V) measurements were obtained in multiple venules of each subject. Data were categorized according to venule caliber by averaging V and D for venules with diameters less than (vessel size 1) or greater than (vessel size 2) 15 µm. V in vessel size 2 was significantly greater than V in vessel size 1 in the AA and SS groups (P ≥ 0.009), but not in the SC group (P = 0.1). V was significantly lower in the SC group as compared to the SS group (P = 0.03). In AA and SS groups, V correlated with D (P ≤ 0.005), but the correlation was not statistically significant in the SC group (P = 0.08). V was inversely correlated with hematocrit in the SS group for large vessels (P = 0.03); however, no significant correlation was found in the SC group (P ≥ 0.2). Quantitative assessment of conjunctival microvascular hemodynamics in SS and SC disease may advance understanding of sickle cell disease pathophysiology and thereby improve therapeutic interventions.
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Affiliation(s)
- Justin Wanek
- Department of Ophthalmology and Visual Sciences; University of Illinois at Chicago; IL
| | - Bruce Gaynes
- Department of Ophthalmology; Loyola University Stritch School of Medicine; Maywood; IL
| | - Jennifer I. Lim
- Department of Ophthalmology and Visual Sciences; University of Illinois at Chicago; IL
| | | | - Mahnaz Shahidi
- Department of Ophthalmology and Visual Sciences; University of Illinois at Chicago; IL
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Gee BE. Biologic complexity in sickle cell disease: implications for developing targeted therapeutics. ScientificWorldJournal 2013; 2013:694146. [PMID: 23589705 PMCID: PMC3621302 DOI: 10.1155/2013/694146] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 01/29/2013] [Indexed: 01/01/2023] Open
Abstract
Current therapy for sickle cell disease (SCD) is limited to supportive treatment of complications, red blood cell transfusions, hydroxyurea, and stem cell transplantation. Difficulty in the translation of mechanistically based therapies may be the result of a reductionist approach focused on individual pathways, without having demonstrated their relative contribution to SCD complications. Many pathophysiologic processes in SCD are likely to interact simultaneously to contribute to acute vaso-occlusion or chronic vasculopathy. Applying concepts of systems biology and network medicine, models were developed to show relationships between the primary defect of sickle hemoglobin (Hb S) polymerization and the outcomes of acute pain and chronic vasculopathy. Pathophysiologic processes such as inflammation and oxidative stress are downstream by-products of Hb S polymerization, transduced through secondary pathways of hemolysis and vaso-occlusion. Pain, a common clinical trials endpoint, is also complex and may be influenced by factors outside of sickle cell polymerization and vascular occlusion. Future sickle cell research needs to better address the biologic complexity of both sickle cell disease and pain. The relevance of individual pathways to important sickle cell outcomes needs to be demonstrated in vivo before investing in expensive and labor-intensive clinical trials.
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Affiliation(s)
- Beatrice E Gee
- Department of Pediatrics, Cardiovascular Research Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310-1495, USA.
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