Comparative erythrocyte deformability investigations by filtrometry, slit-flow and rotational ektacytometry in a long-term follow-up animal study on splenectomy and different spleen preserving operative techniques: Partial or subtotal spleen resection and spleen autotransplantation

Metabolic Influences Modulating Erythrocyte Deformability and Eryptosis

Many factors in the surrounding environment have been reported to influence erythrocyte deformability. It is likely that some influences represent reversible changes in erythrocyte rigidity that may be involved in physiological regulation, while others represent the early stages of eryptosis, i.e., the red cell self-programmed death. For example, erythrocyte rigidification during exercise is probably a reversible physiological mechanism, while the alterations of red blood cells (RBCs) observed in pathological conditions (inflammation, type 2 diabetes, and sickle-cell disease) are more likely to lead to eryptosis. The splenic clearance of rigid erythrocytes is the major regulator of RBC deformability. The physicochemical characteristics of the surrounding environment (thermal injury, pH, osmolality, oxidative stress, and plasma protein profile) also play a major role. However, there are many other factors that influence RBC deformability and eryptosis. In this comprehensive review, we discuss the various elements and circulating molecules that might influence RBCs and modify their deformability: purinergic signaling, gasotransmitters such as nitric oxide (NO), divalent cations (magnesium, zinc, and Fe2+), lactate, ketone bodies, blood lipids, and several circulating hormones. Meal composition (caloric and carbohydrate intake) also modifies RBC deformability. Therefore, RBC deformability appears to be under the influence of many factors. This suggests that several homeostatic regulatory loops adapt the red cell rigidity to the physiological conditions in order to cope with the need for oxygen or fuel delivery to tissues. Furthermore, many conditions appear to irreversibly damage red cells, resulting in their destruction and removal from the blood. These two categories of modifications to erythrocyte deformability should thus be differentiated.

Use of a Bipolar Vessel-Sealing Device for Splenic Parenchymal Resection in Three Dogs and One Cat

Based on splenic abnormalities noted during surgery, four client-owned animals (three dogs, one cat) undergoing exploratory laparotomy were identified as candidates for partial splenectomy. In three cases, small mass lesions of the spleen were identified on elective exploratory laparotomy. In one case, the patient was referred for emergency surgery for diaphragmatic hernia with entrapment of stomach and spleen. The discovery of avulsion of a significant portion of the splenic mesentery led to the decision to perform partial splenectomy in this case. All animals included in the study underwent partial splenectomy by one of two board-certified veterinary surgeons at a multispecialty hospital between 2014 and 2018. The same type of bipolar vessel-sealing device was used in each surgery, and three of four partial splenectomy cases recovered uneventfully. One patient went into cardiopulmonary arrest hours after surgery and died; however, this is not suspected to be due to the described partial splenectomy technique. The bipolar vessel-sealing device is suitable for use in resection of the splenic parenchyma in some canine and feline patients. This technique is designed to decrease surgical time, provide effective hemostasis, and preserve the important functions of the spleen that are lost when total splenectomy is undertaken.

Hemorheological Alteration in Patients with Cirrhosis Clinically Diagnosed with Portal Vein System Thrombosis After Splenectomy

Background

Portal vein system thrombosis (PVST) is a common and serious complication after splenectomy. Key factors, including wider diameters of the portal vein, decreased liver function, and high flow volume of portosystemic collateral vessel, are recognized PVST risks. Relationships between PVST and altered hemorheology, including increased plasma viscosity, remain unclear. We investigated hemorheological alterations and explored risk factors of PVST in patients with cirrhosis after splenectomy.

Material/Methods

Data on patients with cirrhosis who underwent splenectomy were collected retrospectively from January 2018 to June 2020. Color Doppler ultrasonography was performed after splenectomy. Hemorheological indexes were compared between groups. Receiver operating characteristic (ROC) analysis was conducted to analyze risk factor cutoff values. Univariate and multivariate analyses were conducted to explore risk factors of PVST.

Results

A total of 50 patients were divided into a PVST group (n=30) and control group (n=20). Hemorheological indexes of activated partial thromboplastin time, fibrinogen degradation products (FDP), D-dimer, middle shear rates 50 and 30, low shear rates 5 and 1, and hematocrit in the PVST group were significantly higher than those of the control group (P<0.05). FDP and low shear rate 1 were found to be risk factors of PVST after splenectomy by multivariate analysis. ROC analysis showed that the cutoff points for FDP and low shear rate 1 were ≥38.6 ug/mL and ≥16.855 mPa.s, respectively.

Conclusions

PVST after splenectomy is closely related to hemorheological alteration. FDP and low shear rate 1 may be valuable markers of PVST.

Evaluation of cytological diagnostic accuracy for canine splenic neoplasms: An investigation in 78 cases using STARD guidelines

Cytology represents a useful diagnostic tool in the preliminary clinical approach to canine splenic lesions, and may prevent unnecessary splenectomy. However, few studies have evaluated diagnostic accuracy of cytology in the diagnosis of canine splenic neoplasms. The aim of this study was to determine overall accuracy, sensitivity, specificity, positive and negative predictive values (i.e. diagnostic accuracy indexes) of cytology for canine splenic neoplasms following Standards for the Reporting of Diagnostic Accuracy Studies (STARD) guidelines. A consecutive series of canine splenic cytological samples was retrospectively retrieved from the database of the Diagnostic Pathology Service of the Department of Veterinary Medicine (DIMEVET—University of Milan). Histopathology was set as the diagnostic reference standard. Cytological cases were enrolled when slides were available for review and when the same lesion was submitted for histopathology. Seventy-eight (78) lesions were included in the study. By histopathology, 56 were neoplastic and 22 were non-neoplastic. Cytology had an overall accuracy of 73.08% (95% C.I. 61.84%-82.50%), sensitivity of 64.29% (95% C.I. 50.36%-76.64%), specificity of 95.45% (95% C.I. 77.16%-99.88%), and positive and negative predictive values of 97.3% (95% C.I. 84.01%-99.60%) and 51.22% (95% C.I. 42.21%-60.15%), respectively. Low sensitivity and negative predictive value were balanced by very high specificity and positive predictive value. When positive for neoplasia, cytology represents a useful diagnostic tool to rule in splenic neoplasia, prompting surgery independently from other diagnostic tests. Conversely, a negative cytological result requires additional investigations to confirm the dog to be disease free.

Effects and influencing factors on hemorheological variables taken into consideration in surgical pathophysiology research

In surgical pathophysiology ischemia-reperfusion, inflammatory processes, sepsis, vascular interventions, tissue trauma, shock, all mean conditions in which hemorheological parameters show alterations. Despite of numerous clinical and experimental studies, the in vivo hemorheology is not completely understood yet, and several fundamental questions still need to be answered. Investigating these issues, experimental surgical models are important, in point of view of the translational research as well. In this paper we aimed to make an attempt on summarizing the possible factors and conditions that might have an effect on hemorheological results in experimental surgical studies. Hemorheological parameters show alterations in surgical pathophysiological processes in a complex way. However, the changes are dominantly non-specific. Standardized experimental conditions, related to the experimental animal (species, animal welfare) anesthesia-medications, operation, sampling and, if applicable, conditions of the postoperative period, are inevitable for a safe assessment of valuable (hemorheological) results. Parallel investigations - such as microcirculatory monitoring, imaging techniques, other laboratory methods, histomorphology- have great importance, together with individual analysis of changes, for a better understanding of the changes and for comparability with clinical results.