Hemoglobin Binding to the Red Blood Cell (RBC) Membrane Is Associated with Decreased Cell Deformability.

The deformability of red blood cells (RBCs), expressing their ability to change their shape as a function of flow-induced shear stress, allows them to optimize oxygen delivery to the tissues and minimize their resistance to flow, especially in microcirculation. During physiological aging and blood storage, or under external stimulations, RBCs undergo metabolic and structural alterations, one of which is hemoglobin (Hb) redistribution between the cytosol and the membrane. Consequently, part of the Hb may attach to the cell membrane, and although this process is reversible, the increase in membrane-bound Hb (MBHb) can affect the cell's mechanical properties and deformability in particular. In the present study, we examined the correlation between the MBHb levels, determined by mass spectroscopy, and the cell deformability, determined by image analysis. Six hemoglobin subunits were found attached to the RBC membranes. The cell deformability was negatively correlated with the level of four subunits, with a highly significant inter-correlation between them. These data suggest that the decrease in RBC deformability results from Hb redistribution between the cytosol and the cell membrane and the respective Hb interaction with the cell membrane.

Post-operative anterior diaphragmatic hernias in children with Trisomy 21 after cardiac surgery.

Morgagni hernias account for less than 5% of congenital diaphragmatic hernias. They are characteristically retrosternal and bilateral, with right-sided predominance. An association between Trisomy 21 and diaphragmatic hernias resembling Morgagni hernia has been reported, but the effect of cardiac surgery on its formation has not been investigated. The purpose of this study was to determine whether there is a higher incidence of anterior diaphragmatic hernias in children with Trisomy 21 after cardiac surgery. We compared the prevalence of anterior diaphragmatic hernias in 92 patients with Trisomy 21 who underwent cardiac surgery with its prevalence in 100 children without Trisomy 21 who underwent cardiac surgery. All available CXRs of all children underwent revision for the presence of an anterior diaphragmatic hernia by a pediatric radiologist. Within the study group, four cases of an anterior diaphragmatic hernia were detected, all upon presentation to the emergency room due to breathing difficulties. No cases of an anterior diaphragmatic hernia were found in the control group (P = 0.0094). CONCLUSIONS: A high index of suspicion for an anterior diaphragmatic hernia should be maintained in children with Trisomy 21 who have undergone cardiac surgery and present with breathing difficulty. If CXR findings are uncertain, UGI series and\or CT should be performed. In light of our findings, the surgical technique has been modified in patients with DS in our medical center. WHAT IS KNOWN: • Several studies reported an association between Trisomy 21 and diaphragmatic hernia resembling Morgagni hernia, but the effect of cardiac surgery on its formation has not been investigated. WHAT IS NEW: • There is a higher incidence of anterior diaphragmatic hernia resembling a Morgagni hernia in children with Trisomy 21 after cardiac surgery. • A high index of suspicion for an anterior diaphragmatic hernia should be maintained in children with Trisomy 21 who have undergone cardiac surgery and present with breathing difficulty. If CXR findings are uncertain, UGI series and\or CT should be performed.

Red Blood Cell Deformability Is Expressed by a Set of Interrelated Membrane Proteins.

Red blood cell (RBC) deformability, expressing their ability to change their shape, allows them to minimize their resistance to flow and optimize oxygen delivery to the tissues. RBC with reduced deformability may lead to increased vascular resistance, capillary occlusion, and impaired perfusion and oxygen delivery. A reduction in deformability, as occurs during RBC physiological aging and under blood storage, is implicated in the pathophysiology of diverse conditions with circulatory disorders and anemias. The change in RBC deformability is associated with metabolic and structural alterations, mostly uncharacterized. To bridge this gap, we analyzed the membrane protein levels, using mass spectroscopy, of RBC with varying deformability determined by image analysis. In total, 752 membrane proteins were identified. However, deformability was positively correlated with the level of only fourteen proteins, with a highly significant inter-correlation between them. These proteins are involved in membrane rafting and/or the membrane-cytoskeleton linkage. These findings suggest that the reduction of deformability is a programmed (not arbitrary) process of remodeling and shedding of membrane fragments, possibly mirroring the formation of extracellular vesicles. The highly significant inter-correlation between the deformability-expressing proteins infers that the cell deformability can be assessed by determining the level of a few, possibly one, of them.

The inhibition of glucose uptake to erythrocytes: microwave dielectric response.

Dielectric spectroscopy has been used in the study and development of non-invasive glucose monitoring (NIGM) sensors, including the range of microwave frequencies. Dielectric relaxation of red blood cell (RBC) cytosolic water in the microwave frequency band has been shown to be sensitive to variations in the glucose concentration of RBC suspensions. It has been hypothesized that this sensitivity stems from the utilization of D-glucose by RBCs. To verify this proposition, RBCs were pretreated with inhibitors of D-glucose uptake (cytochalasin B and forskolin). Then their suspensions were exposed to different D-glucose concentrations as measured by microwave dielectric spectroscopy (MDS) in the 500 MHz-40 GHz frequency band. After incubation of RBCs with either inhibitor, the dielectric response of water in the cytoplasm, and specifically its relaxation time, demonstrated minimal sensitivity to the change of D-glucose concentration in the medium. This result allows us to conclude that the sensitivity of MDS to glucose uptake is associated with variations in the balance of bulk and bound RBC cytosolic water due to intracellular D-glucose metabolism, verifying the correctness of the initial hypothesis. These findings represent a further argument to establish the dielectric response of water as a marker of glucose variation in RBCs.

Unit-to-unit variability in the deformability of red blood cells.

BACKGROUND: In blood banking practice, the storage duration is used as the primary criterion for inventory management, and usually, the packed red blood cells (PRBC) units are supplied primarily according to first-in-first-out (FIFO) principle. However, the actual functionality of individual PRBC units is mostly ignored. One of the main features of the RBCs not accounted for under this approach is the deformability of the red cells, i.e., their ability to affect the recipients' blood flow. The objective of the study was to analyze unit-to-unit variability in the deformability of PRBCs during their cold storage. METHODS: RBC samples were obtained from twenty leukoreduced PRBC units, stored in SAGM. The deformability of cells was monitored from the day of donation throughout 42 days. RBC deformability was determined using the computerized cell flow-properties analyzer (CFA) based on cell elongation under a shear stress of 3.0 Pa, expressed by the elongation-ratio (ER). The image analysis determines the ER for each cell and provides the ER distribution in the population of 3000-6000 cells. RESULTS: The deformability of freshly-collected RBCs exhibited marked variability already on the day of donation. We also found that the aging curve of PRBC deformability varies significantly among donors. SIGNIFICANCE: The present study has demonstrated that storage duration is only one of the factors, and seemingly not even the major one, affecting the PRBCs functionality. Therefore, the FIFO approach is not sufficient for assessing the potential transfusion outcome, and the PRBC functionality should be determined explicitly for each unit.

Preparation of packed red blood cell units in the blood bank: Alteration in red blood cell deformability.

BACKGROUND: Donated blood is stored in the blood bank as packed red blood cell units. In the process of packed cells preparation, the red blood cells (RBCs) are subjectedto high level of shear stress, which can induce alterations in their properties. In the present study, we examined the effect of packed RBCs preparation (which included leuko-filtration) on red cell deformability. METHODS: Blood samples were collected from 25 healthy donors and from corresponding units of packed RBCs. The portion of undeformable cells (%UDFC) was determined for each sample. RESULTS: The median value of %UDFC was equal to 6.75 ± 0.70 %, for freshly-donated RBCs, and to 6.36 ± 0.51 %, for packed cells. Wherein, %UDFC may increase or decrease following packed cells preparation, depending upon the initial portion of undeformable cells. CONCLUSION: Likely, exposure of RBCs to high shear stress, during packed cells preparation, induces opposing effects: (a) removal/destruction of rigid (undeformable) cells, thereby reducing their total amount (i.e., decreasing the %UDFC) on the one hand, and (b) mechanical damage to the cell membrane and subsequent reduction of the cell deformability (thereby increasing the %UDFC) on the other. As a consequence, the final impact of packed cells preparation is primarily determined by the initial state of erythrocytes in the blood of the donor.

Inter-donor variability in deformability of red blood cells in blood units.

OBJECTIVE: This study aimed to examine the donor-to-donor variability in the deformability of red blood cells (RBCs) from freshly collected blood donations (F-RBC) and packed RBCs. BACKGROUND: Packed RBCs are supplied for transfusion by the first-in-first-out (FIFO) criterion, assuming that their quality is the same for packed RBCs with equal storage duration. To challenge this notion, we determined the deformability of F-RBC and packed RBCs stored for different durations. METHODS: Three RBC groups were employed: A. 79 samples of F-RBC; B. 76 samples of packed RBC units, randomly used for transfusion at different storage durations; and C. 65 samples of outdated packed RBCs stored for 35 to 37 days. All packed RBC units were non-leukofiltrated and stored in Citrate-phosphate-dextrose solution with adenine (CPDA-1). RBC deformability was determined using a computerised cell-flow properties analyser, which monitors the shape change of cells directly visualised in a narrow-gap flow chamber and provides the cells' deformability distribution in a large RBC population. RESULTS: The F-RBC deformability exhibited a wide-range inter-donor variability. The cold storage of packed RBCs exerted a mild reduction of deformability, which became significant, compared to the initial inter-donor variability, only after 3 weeks of storage. CONCLUSION: Packed RBCs are generally supplied for transfusion by the FIFO criterion based on the assumption that the storage duration is a key factor of RBC quality. This study demonstrates that the deformability of red blood cells is significantly different in donors, and substantial variability persists throughout the entire process of their storage. Therefore, the FIFO criterion is not sufficient for assessing the RBC deformability, which should, therefore, be specifically characterised for each unit.

[ADVANCES IN FETAL THERAPY IN COMPLICATED MONOCHORIONIC PREGNANCIES AND IN SEVERE CONGENITAL DIAPHRAGMATIC HERNIA: FIVE YEARS EXPERIENCE].

INTRODUCTION: : Minimally invasive fetal therapeutic procedures reduce the morbidity and mortality in monochorionic (MC) twins and in fetuses with congenital diaphragmatic hernia (CDH). MC pregnancies share their blood systems due to communicating vessels over their single placenta and may develop specific complications: Twin-to-Twin transfusion syndrome (TTTS), Selective intrauterine growth restriction (sIUGR), Twin Anemia-Polycythemia Sequence (TAPS), Twin Reverse Arterial Perfusion Syndrome (TRAP) or anomalies in one. Half of complicated MC require intrauterine interventions. Severe CDH is linked to a high rate of neonatal death due to pulmonary hypoplasia. Fetoscopic tracheal occlusion (FETO) with a balloon improves postnatal outcome. AIMS: A fetal therapy center was established in the Hadassah Medical Centers, Jerusalem in 2011 for intrauterine interventions. We report our 5 years' experience. METHODS: This prospective cohort follows the outcome of MC pregnancies and cases of severe CDH which underwent therapeutic fetal procedures in Hadassah between the years 2011-16. RESULTS: Out of 114 procedures, 95 were in MC: 84 monochorionic diamniotic twins, 7 monochorionic monoamniotic twins, 2 dichorionic triamniotic triplets and 2 monochorionic triplets. We treated 65 TTTS cases with fetoscopy and laser ablation of communicating vessels. The survival rate of both twins was 58.5% and at least one survived in 81.5% of the cases. In 2nd/3rd trimesters selective termination of 15 cases the survival rate of the remaining twin was 87%. In 11 cases of TRAP sequence treated with laser ablation of the feeding vessel the survival of the remaining twin was 91%. In 19 fetoscopies in severe CDH, 12 were for balloon insertion and 7 for removal. Endotracheal balloon was successfully placed in 11 of 12 cases (10 left-sided, 1 right-sided CDH). Balloon removal was prenatally performed by elective fetoscopy (n=7) or by intrapartum urgent puncture. There were no intrauterine fetal deaths. In isolated left-sided CDH the survival was 57%, whereas none survived in non-isolated left-sided CDH and right sided CDH. CONCLUSIONS: In-utero procedures are safe for the mother and increase newborn survival in MC pregnancies, thus specialized clinics are life-saving. FETO is a therapeutic option for severe CDH. Our results meet similar achievements reported by other leading world centers.

Characteristics of mesenteric lymphadenitis in comparison with those of acute appendicitis in children.

Mesenteric lymphadenitis (ML) is considered as one of the most common alternative diagnosis in a child with suspected acute appendicitis (AA). In this retrospective study, patients diagnosed with ML (n = 99) were compared in terms of demographic, clinical, and laboratory findings to patients diagnosed with AA (n = 102). This comparison was applied for both lymph nodes smaller and larger than 10 mm. When compared to patients with AA, patients with ML had significantly longer duration of symptoms prior to emergency department (ED) presentation (2.4 ± 2.6 vs 1.4 ± 1.4 days, P = 0.002) and multiple ED presentations (1.3 ± 0.7 vs 1.05 ± 0.3, P < 0.001) and had longer duration of stay in the ED (9.2 ± 5.9 vs 5.2 ± 4 h, P < 0.001), respectively. They also had significantly lower WBC (10.16 ± 4.7 × 103/dl vs 15.8 ± 4.4 × 103/dl, P < 0.001) with lymphocyte predominance (24.6 ± 14 vs 13 ± 8.7%, P < 0.001) and lower CRP levels (0.48 vs 1.6 mg/dl). Migration of pain (28 vs 7%), vomiting (62 vs 34%), and classic abdominal findings of AA (72 vs 20%) were all significantly more common for children with AA. When comparing lymph node size, no significant difference was found between those presenting with small and large nodes. CONCLUSION: This study highlights multiple clinical and laboratory findings that differentiate ML and AA. Moreover, the absence of any difference with regard to the lymph nodes size might suggest that lymph nodes enlargement is a non-specific finding. What is Known : • Mesenteric lymphadenitis is a very common diagnosis in children with suspected acute appendicitis. • Despite its prevalence, only few studies addressed the clinical characteristics of this clinical entity and their comparison with acute appendicitis. What is New: • Mesenteric lymphadenitis and acute appendicitis could be differentiated by multiple clinical and laboratory parameters. • No significant difference was found between those presenting with small and large lymph nodes.

Deformability of transfused red blood cells is a potent determinant of transfusion-induced change in recipient's blood flow.

OBJECTIVE: There is a growing concern regarding the risks in the transfusion of PRBC, as numerous studies have reported negative transfusion outcomes, including reduced blood perfusion. In search of this phenomenon's mechanism, the effect of PRBC deformability, a major determinant of blood flow, on transfusion outcome was explored. METHODS: The effect of PRBC deformability was examined by the transfusion-induced change in recipients' ∆SBF, in ß-TM patients, who are routinely treated with lifelong frequent transfusions. SBF was determined using a laser Doppler imager. RESULTS: ∆SBF was examined vs PRBC deformability, the transfusion-induced increase in ∆Hct and the recipients' SBF before transfusion (SBFB ). ∆SBF elevated with increasing PRBC deformability, with a highly significant dependence, while its elevation with ∆Hct was much less significant. ∆SBF was inversely proportional to the SBFB . CONCLUSIONS: This study provides, for the first time in humans, direct evidence that the deformability of transfused PRBC is a potent effector of transfusion outcome. Currently, PRBC are supplied primarily by the first-in-first-out criteria, while their functionality is ignored. The testing of PRBC hemodynamic quality would introduce a new paradigm into blood banking, which would contribute substantially to improving transfusion therapy.

Storage-induced damage to red blood cell mechanical properties can be only partially reversed by rejuvenation.

BACKGROUND: The storage of red blood cells (RBC) is associated with impairment of their properties that can induce a circulatory risk to recipients. In a preceding study (2009), we reported that post-storage rejuvenation (RJ) of stored RBC (St-RBC) efficiently reduced the storage-induced RBC/endothelial cell interaction, while only partially reversing the level of intracellular Ca(2+), reactive oxygen species, and surface phosphatidylserine. In the present study, we examined the RJ effectiveness in repairing St-RBC mechanical properties. METHODS: RBC, stored in CPDA-1 without pre-storage leukoreduction, were subjected to post-storage RJ, and the deformability, osmotic fragility (OF), and mechanical fragility (MF) of the rejuvenated St-RBC (St-RBCRj) were compared to those of untreated St-RBC and of freshly-collected RBC (F-RBC). RESULTS: 5-week storage considerably increased OF and MF, and reduced the deformability of St-RBC. All alterations were only partially (40-70%) reversed by RJ, depending on the extent of the damage: the greater the damage, the lesser the relative effect of RJ. CONCLUSION: The findings of the present and preceding studies suggest that different St-RBC properties are differentially reversed by RJ, implying that some of the changes occur during storage and are irreversible.

Endovascular management of blunt renal artery trauma.

BACKGROUND: Renal artery injuries are rarely encountered in victims of blunt trauma. However, the rate of early diagnosis of such injuries is increasing due to increased awareness and the liberal use of contrast-enhanced CT. Sporadic case reports have shown the feasibility of endovascular management of blunt renal artery injury. However, no prospective trials or long-term follow-up studies have been reported. OBJECTIVES: To present our experience with endovascular management of blunt renal artery injury, and review the literature. METHODS: We conducted a retrospective study of 18 months at a level 1 trauma center. Search of our electronic database and trauma registry identified three patients with renal artery injury from blunt trauma who were successfully treated endovascularly. Data recorded included the mechanism of injury, time from injury and admission to revascularization, type of endovascular therapy, clinical and imaging outcome, and complications. RESULTS: Mean time from injury to endovascular revascularization was 193 minutes and mean time from admission to revascularization 154 minutes. Stent-assisted angioplasty was used in two cases, while angioplasty alone was performed in a 4 year old boy. A good immediate angiographic result was achieved in all patients. At a mean follow-up of 13 months the treated renal artery was patent in all patients on duplex ultrasound. The mean percentage renal perfusion of the treated kidney at last follow-up was 36% on DTPA renal scan. No early or late complications were encountered. CONCLUSIONS: Endovascular management for blunt renal artery dissection is safe and feasible if an early diagnosis is made. This approach may be expected to replace surgical revascularization in most cases.

Determination of red blood cell adhesion to vascular endothelial cells: A critical role for blood plasma.

Red blood cell (RBC) adhesion to vascular endothelial cells (EC) is considered a potent effector of circulatory disorders, and its enhancement is implicated in the pathophysiology of numerous conditions, mainly hemoglobinopathies. The actual RBC/EC interaction is determined by both cellular and plasmatic factors, and the differentiation between them is essential for understanding its physiological implications. Yet, RBC/EC adhesion has been studied predominantly in protein-free media. To explore the plasma contribution to RBC/EC adhesion, we examined the adhesion of human RBC to human vascular endothelial cells in the presence of fresh frozen plasma (FFP) and compared it to that in a protein-free phosphate-buffered saline (PBS). RBC from blood samples freshly-collected from five healthy donors and from fifteen units of packed RBC units were used. The same FFP sample was used in all measurements. In FFP, the RBC form strongly adherent aggregates, which are dispersed as the shear stress (τ) increases to 3.0 Pa, and even at 5.0 Pa a large portion of the RBC are still adherent. In PBS, the RBC are singly dispersed and their adhesion becomes insignificant already at τ = 0.5 Pa. No cross-correlation was found between the adhesion in PBS vs. that in FFP at the same τ. However, in both media, under conditions that form singly dispersed adherent RBC, an inverse correlation between RBC/EC adhesion in PBS vs. that in FFP was observed. This study clearly implies that for understanding the physiological relevance of RBC/EC adhesion it should be determined in plasma.

Bowel Resection Through a Single Umbilical Incision: A Case Series.

Background: The advent of laparoscopy has revolutionized surgery. The surgeon strives to minimize incisions and their adverse consequences. Although laparoscopy has gained widespread popularity, several advantages in open surgery are thereby lost. Tactile sensation of the tissue, hand-sewn anastomosis, and nonthermic vascular control are most prominent. To combine both approaches, single incision laparoscopic-assisted surgery (SILS) was advanced, trying to combine the best in both worlds. This approach is widely used in appendectomies. After having gained experience in this approach, we expanded the indications and hereby present our experience with bowel resections utilizing SILS. Patients and Methods: Data were collected retrospectively from operations performed during the past 3 years. We found 11 cases of SILS bowel resections: 3 sigmoidectomies, 3 small bowel atresia repairs, 1 subtotal colectomy, 1 Meckel's diverticulectomy, and 3 resections of bowel duplications. The age of the patients ranged from 2 days to 17 years. In all cases, a working 10 mm scope was inserted through the umbilicus, the bowel was extracted outside the abdomen through the umbilicus, dissection and resection with anastomosis were performed outside the abdomen in the classic open approach, and the bowel was returned to the abdomen. Results and Conclusions: All patients recovered promptly with no need for further intervention. There were no cases of wound infection, leak, or intra-abdominal abscess formation. Cosmesis was excellent with a small umbilical scar. We conclude that this approach is feasible and safe in a select population.

Deformability of cord blood vs. newborns' red blood cells: implication for blood transfusion.

AIM: About 50% of premature neonates (PN) are treated with transfusion of packed red blood cells (PRBC) collected from adult donors, which has been suggested to potentially provoke PN pathologies, characterized as blood circulation disorders. RBC have properties that are key determinants of blood circulation, primarily the cell deformability. In previous studies we have shown that transfusion of RBC with reduced deformability impaired the transfusion outcome. Although RBC of PN (PN-RBC) are larger, and their microvessels are narrower than those of adults, their blood circulation is very efficient, pointing to the possibility that the deformability of adults' PRBC is inferior to that of PN-RBC, and that treating PN with PRBC transfusion might, therefore, introduce a risk to the recipients. This would infer that PN should be given RBC with high deformability. However, since using PN-RBC is not feasible, the use of cord blood RBC (CB-RBC) is a sound alternative, assuming that the deformability of CB-RBC is comparable to that of PN-RBC.The present study is aimed at testing this hypothesis. METHODS: We compared the deformability of (1) RBC of PN vs. the PRBC they received, and (2) PN-RBC vs. their autologous CB-RBC. RESULTS: 1. The deformability of the transfused PRBC is indeed inferior to that of PN-RBC. 2. The deformability of CB-RBC is equivalent to that of PN-RBC. CONCLUSION: This study supports the notion that treating PN with transfusion of adults' PRBC has the potential to introduce a circulatory risk to the recipients, while CB-RBC, with their superior deformability, provides a safer and more effective PN-specific transfusion therapy.

Do We Store Packed Red Blood Cells under "Quasi-Diabetic" Conditions?

Red blood cell (RBC) transfusion is one of the most common therapeutic procedures in modern medicine. Although frequently lifesaving, it often has deleterious side effects. RBC quality is one of the critical factors for transfusion efficacy and safety. The role of various factors in the cells' ability to maintain their functionality during storage is widely discussed in professional literature. Thus, the extra- and intracellular factors inducing an accelerated RBC aging need to be identified and therapeutically modified. Despite the extensively studied in vivo effect of chronic hyperglycemia on RBC hemodynamic and metabolic properties, as well as on their lifespan, only limited attention has been directed at the high sugar concentration in RBCs storage media, a possible cause of damage to red blood cells. This mini-review aims to compare the biophysical and biochemical changes observed in the red blood cells during cold storage and in patients with non-insulin-dependent diabetes mellitus (NIDDM). Given the well-described corresponding RBC alterations in NIDDM and during cold storage, we may regard the stored (especially long-stored) RBCs as "quasi-diabetic". Keeping in mind that these RBC modifications may be crucial for the initial steps of microvascular pathogenesis, suitable preventive care for the transfused patients should be considered. We hope that our hypothesis will stimulate targeted experimental research to establish a relationship between a high sugar concentration in a storage medium and a deterioration in cells' functional properties during storage.