Optimal intervention time of ADSCs for hepatic ischemia-reperfusion combined with partial resection injury in rats.

AIMS: Hepatic ischemia reperfusion injury (HIRI) is a complication of liver surgery and liver transplantation. Adipose-derived stem cells (ADSCs) can inhibit oxidative stress and inflammation through a paracrine effect. This study aimed to determine the optimal time window of ADSCs transplantation to restore liver function after HIRI. MAIN METHODS: A rat model of hepatic ischemia reperfusion combined with partial hepatectomy (HIR/PH) was established. The animals were injected intravenously with 2 × 106 rat ADSCs 2 h before, immediately after, or 6 h after surgery. Liver tissues and blood samples were collected for routine histological and biochemical assays. The molecular changes were analyzed by qRT-PCR and western blotting. KEY FINDINGS: ADSCs significantly improved liver tissue structure and decreased the levels of AST, ALT and ALP, which was indicative of functional recovery. In addition, transplantation of ADSCs immediately after operation decreased the levels of inflammation-related cytokines such as TNF-α, IL-1ß and IL-6, and significantly increased the activity of antioxidant enzymes. At the same time, the expression of MDA was decreased. Mechanistically, ADSCs activated the Keap1/Nrf2 pathway in the injured liver. Transplantation of ADSCs pre- and 6 h post-operation did not significantly affect some indices such as mRNA and protein expression of HO-1, and protein expression of NQO1. SIGNIFICANCE: Transplanting ADSCs immediately after surgery accelerated tissue repair and functional recovery of the liver by activating the Keap1/Nrf2 pathway, which inhibited hepatic inflammation and oxidative stress, and restored the hepatic microenvironment.

Tetramethylpyrazine inhibits neutrophil extracellular traps formation and alleviates hepatic ischemia/reperfusion injury in rat liver transplantation.

Hepatic ischemia/reperfusion injury (IRI) is an adverse effect for liver transplantation which is characterized by immune response mediated inflammation. Recent studies report that neutrophil extracellular traps (NETs) are implicated in hepatic IRI. The aim of this study was to explore the mechanism of action of tetramethylpyrazine (TMP), the main chemical composition of Ligusticum chuanxiong in treatment of ischemic related diseases. Data showed that hepatic IRI increases the leak of alanine aminotransferase (ALT) and aspartate transaminase (AST), and stimulates formation of NETs. Extracellular DNA/NETs assay, hematoxylin-eosin (HE) staining, immunofluorescence assay, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and Western blot assay, showed that TMP significantly reduces formation of NETs and alleviates hepatic IRI. Moreover, TMP and Diphenyleneiodonium (DPI) suppressed ROS production in neutrophils. In addition, analysis showed that activation of NADPH oxidase plays a role in formation of NETs triggered by hepatic IRI. Notably, TMP inhibited formation of NETs though inhibition of NADPH oxidase. Additionally, Combination treatment using TMP and DPI was more effective compared with monotherapy of either of the two drugs. These findings show that combination therapy using TMP and DPI is a promising method for treatment hepatic IRI.

Deficiency of myostatin protects skeletal muscle cells from ischemia reperfusion injury.

Ischemia reperfusion (IR) injury plays a pivotal role in many diseases and leads to collateral damage during surgical interventions. While most studies focus on alleviating its severity in the context of brain, liver, kidney, and cardiac tissue, research as regards to skeletal muscle has not been conducted to the same extent. In the past, myostatin (MSTN), primarily known for supressing muscle growth, has been implicated in inflammatory circuits, and research provided promising results for cardiac IR injury mitigation by inhibiting MSTN cell surface receptor ACVR2B. This generated the question if interrupting MSTN signaling could temper IR injury in skeletal muscle. Examining human specimens from free myocutaneous flap transfer demonstrated increased MSTN signaling and tissue damage in terms of apoptotic activity, cell death, tissue edema, and lipid peroxidation. In subsequent in vivo MstnLn/Ln IR injury models, we identified potential mechanisms linking MSTN deficiency to protective effects, among others, inhibition of p38 MAPK signaling and SERCA2a modulation. Furthermore, transcriptional profiling revealed a putative involvement of NK cells. Collectively, this work establishes a protective role of MSTN deficiency in skeletal muscle IR injury.

Short-term molecular and cellular effects of ischemia/reperfusion on vascularized lymph node flaps in rats.

Vascularized lymph node (VLN) transfer is an emerging strategy to re-establish lymphatic drainage in chronic lymphedema. However, the biological processes underlying lymph node integration remain elusive. This study introduces an experimental approach facilitating the analysis of short-term molecular and cellular effects of ischemia/reperfusion on VLN flaps. Lymph node flaps were dissected pedicled on the lateral thoracic vessels in 44 Lewis rats. VLN flaps were exposed to 45 or 120 minutes ischemia by in situ clamping of the vascular pedicle with subsequent reperfusion for 24 hours. Flaps not exposed to ischemia/reperfusion served as controls. Lymph nodes and the perinodal adipose tissue were separately analyzed by Western blot for the expression of lymphangiogenic and angiogenic growth factors. Moreover, morphology, microvessel density, proliferation, apoptosis and immune cell infiltration of VLN flaps were further assessed by histology and immunohistochemistry. Ischemia for 120 minutes was associated with a markedly reduced cellularity of lymph nodes but not of the perinodal adipose tissue. In line with this, ischemic lymph nodes exhibited a significantly lower microvessel density and an increased expression of VEGF-D and VEGF-A. However, VEGF-C expression was not upregulated. In contrast, analyses of the perinodal adipose tissue revealed a more subtle decrease of microvessel density, while only the expression of VEGF-D was increased. Moreover, after 120 minutes ischemia, lymph nodes but not the perinodal adipose tissue exhibited significantly higher numbers of proliferating and apoptotic cells as well as infiltrated macrophages and neutrophilic granulocytes compared with non-ischemic flaps. Taken together, lymph nodes of VLN flaps are highly susceptible to ischemia/reperfusion injury. In contrast, the perinodal adipose tissue is less prone to ischemia/reperfusion injury.

Mitochondrial transplantation ameliorates ischemia/reperfusion-induced kidney injury in rat.

No real therapeutic modality is currently available for Acute kidney injury (AKI) and if any, they are mainly supportive in nature. Therefore, developing a new therapeutic strategy is crucial. Mitochondrial dysfunction proved to be a key contributor to renal tubular cell death during AKI. Thus, replacement or augmentation of damaged mitochondria could be a proper target in AKI treatment. Here, in an animal model of AKI, we auto-transplanted normal mitochondria isolated from healthy muscle cells to injured kidney cells through injection to renal artery. The mitochondria transplantation prevented renal tubular cell death, restored renal function, ameliorated kidney damage, improved regenerative potential of renal tubules, and decreased ischemia/reperfusion-induced apoptosis. Although further studies including clinical trials are required in this regard, our findings suggest a novel therapeutic strategy for treatment of AKI. Improved quality of life of patients suffering from renal failure and decreased morbidity and mortality rates would be the potential advantages of this therapeutic strategy.

Effects of nalmefene hydrochloride on TLR4 signaling pathway in rats with lung ischemia-reperfusion injury.

OBJECTIVE: To investigate the effect of nalmefene hydrochloride on TLR4 signaling pathway in rats with lung ischemia-reperfusion injury. MATERIALS AND METHODS: Altogether 64 pure inbred male SD rats were divided into groups A, B, C, and D according to the principle of body weight similarity, with 24 rats in each group. Four groups of rats were respectively twisted on the left testis to establish unilateral testicular torsion rats. Group A was the control group, treated with normal saline, group B was the nalmefene hydrochloride high-dose group, treated with 20 µg/kg of nalmefene hydrochloride, group C was the nalmefene hydrochloride low-dose group, treated with 10 µg/kg of nalmefene hydrochloride, and group D was the sham operation group. Lung tissue was collected 60 h later. Western blotting was used to detect the expression levels of HMGB1, TLR4, CD14, and NF-κB protein, qPCR was used to detect the mRNA expression level, and enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of inflammatory factors IL-17, IL-6, and ICAM-1. RESULTS: The expression levels of HMGB1, TLR4, CD14, NF-κB protein, mRNA, IL-17, IL-6, and ICAM-1 in group A were significantly higher than those in groups B, C, and D (p<0.05), while were significantly lower in group D than in groups B and C (p<0.05), and were significantly lower in group B than in group C (p<0.05). CONCLUSIONS: Nalmefene hydrochloride can effectively inhibit the signal pathway of TLR4, and can effectively reduce the injury caused by lung ischemia-reperfusion. The large dose is closely related to the good effect, which is worthy of promotion.

The effects of hydrogen-rich saline solution on intestinal anastomosis performed after intestinal ischemia reperfusion injury.

AIM: We investigated the effects of hydrogen-rich saline solution (HRSS) on intestinal anastomosis performed after intestinal ischemia reperfusion injury (IRI). MATERIALS AND METHODS: Thirty Wistar albino female rats were randomly divided into five groups. Only laparotomy was performed in the Sham group. In the other four groups, an intestinal IRI was performed for 45 min by clamping the superior mesenteric artery. After intestinal IRI, anastomosis was performed by cutting the intestine from the proximal 15 cm of the ileocecal valve at the first and 24th hours. HRSS was given intraperitoneally 5 ml/kg before reperfusion and for four more days in the HRSS1 and HRSS24groups, while no treatment was given to the I/R1 and I/R24 groups. After 5 days, all groups underwent relaparotomy. The anastomotic bursting pressures were measured in all groups, except the Sham group. The tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), myeloperoxidase (MPO) and malondialdehyde (MDA) levels were measured in the tissues taken from the anastomosis line. The tissue sections were evaluated histopathologically and the apoptosis index was determined by applying the TUNEL method. The results were analyzed one-way analysis of variance (ANOVA) and Pearson's chi-squared test. RESULTS: Although the MPO, MDA, IL-6 and TNF-α tissue values were not statistically significant among the groups, the degree of tissue damage and apoptosis levels were lower and the anastomotic bursting pressures values were higher in the HRSS1 and HRSS24 groups compared to the I/R1 and I/R24 groups. CONCLUSION: HRSS is effective in reducing the intestinal damage caused by an IRI: HRSS has the potential to reduce the detrimental effects of intestinal anastomosis performed after an intestinal IRI.

Comparative Evaluation of Translocation of GFP Producing Escherichia coli Strains in Acute Intestinal Obstruction.

Comparative evaluation of translocation of E. coli GFP-producing strains in experimental rats with obturation and strangulated intestinal obstruction was carried out. Translocation of infused GFP-producing E. coli strain was studied by bacteriological methods in male rats with experimental obturation and strangulated intestinal obstruction with various ischemia/reperfusion cycles. The maximum incidence of translocation in obturation intestinal obstruction was observed after 24 h. In strangulated intestinal obstruction, the highest incidence was recorded in ischemia/reperfusion cycles of 1 h/2 h and 2 h/6 h. No appreciable differences in the incidence of translocation in animals with two types of intestinal obstruction were detected.

The protective effect of endothelin receptor antagonists against surgically induced impairment of gastrointestinal motility in rats.

Endothelin (ET) receptor antagonists: BQ-123 (ETA), BQ-788 (ETB), tezosentan (dual ET receptor antagonist) protect against the development of postoperative ileus (POI) evoked by ischemia-reperfusion (I/R). The current experiments explored whether ET antagonists prevent the occurrence of POI evoked by surgical gut manipulation. Intestinal transit was assessed by measuring the rate of dye migration subsequent to skin incision (SI), laparotomy (L), or laparotomy and surgical gut handling (L+M) in diethyl ether anaesthesized rats (E). Experimental animals were randomly sub-divided into two groups depending on the time of recovery following surgery: viz. either 2 or 24 h (early or late phase POI). E and SI did not affect the gastrointestinal (GI) transit. In contrast, L and L+M significantly reduced GI motility in comparison to untreated group (UN). Tezosentan (10 mg/kg), BQ-123 and BQ-788 (1 mg/kg) protected against development of L+M evoked inhibition of intestinal motility in the course of late phase, but not early phase POI. Furthermore, tezosentan alleviated the decrease in the contractile response of the longitudinal jejunal smooth muscle strips to carbachol in vitro induced by L+M. The serum ET(1-21) concentration was not increased in either the early or the late phase POI groups after surgery compared to control animals. This study indicates that delay in the intestinal transit in late phase of surgically induced POI involves an ET-dependent mechanism.

Protective role of N-acetyl-l-tryptophan against hepatic ischemia-reperfusion injury via the RIP2/caspase-1/IL-1ß signaling pathway.

Context: Hepatic ischemia-reperfusion injury (HIRI) is a complex process observed during liver resection and transplantation. N-acetyl-l-tryptophan (l-NAT), an antagonist of neurokinin 1 receptor, has been used for the treatment of nausea and neurodegenerative diseases. Objective: This study investigates the protective effect of l-NAT against HIRI and explores the potential underlying mechanisms. Materials and methods: Adult male Sprague-Dawley (SD) rats were randomly divided into three groups: sham, I/R and I/R + l-NAT. HIRI model was generated by clamping the hepatic artery, portal vein and common bile duct with a microvascular bulldog clamp for 45 min, and then removing the clamp and allowing reperfusion for 6 h. BRL cells were exposed to 200 µM H2O2 with or without 10 µM l-NAT for 6 h. Results: After l-NAT intervention, the structure of hepatic lobules was intact, and no swelling was noted in the cells. Furthermore, cell viability was found to be significantly enhanced when compared with the controls (p < 0.05). The mRNA and protein expression levels of serine-threonine kinase 2 (RIP2) and interleukin-1ß (IL-1ß) were significantly increased in the I/R and H2O2 groups when compared with the controls; however, these levels were significantly decreased after l-NAT intervention. Similarly, IL-1ß activity and caspase-1 activity were significantly decreased in the H2O2 group when compared with the controls, after l-NAT intervention. Conclusions: Our findings indicated that l-NAT may exert a hepatoprotective role in HIRI through inhibiting RIP2/caspase-1/IL-1ß signaling pathway, which can provide evidence for l-NAT to be a potential effective drug against HIRI during clinical practice.

The effect of laparoscopic pre- and postconditioning on pneumoperitoneum induced injury of the peritoneum.

INTRODUCTION: Pneumoperitoneum, widely used in laparoscopic surgery increases the intraabdominal pressure, leading to hypoperfusion of the abdominal organs, and promoting the buildup of reactive oxygen species(ROS) and inflammatory cytokines which in turn impairs the body postoperatively. Aim of our investigation was to evaluate the potential protective effects of short ischemic episodes on ischemic damages. METHODS: 70 Wistar rats were used, divided into 7 groups: 1st group sham, 2nd group pneumoperitoneum with 5 mmHg, 3rd group preconditioning with 5 mmHg, 4th group: postconditioning with 5 mmHg, 5th group pneumoperitoneum with 10 mmHg, 6th group: preconditioning with 10 mmHg, 7th group postconditioning with 10 mmHg. Pneumoperitoneum was created by Veres needle. Oxidative stress parameters: malondialdehyde (MDA) concentration, reduced glutathione (GSH), sulfhydril (SH-), myeloperoxidase (MPO) levels and superoxide-dismutase (SOD) activity were measured. We measured TNF-α and IL-6 concentrations. We monitored the activation of anti- and proapoptotic common signaling pathways (bax, bcl-2, p53) during the early phase of reperfusion. Histology was made from kidney samples. RESULTS: GSH concentrations were significantly reduced, MDA concentrations were significantly higher in each group compared to the Sham. SOD enzyme: a pressure of 10 mmHg elicited significantly greater damage than 5 mmHg. There was a significantly higher SOD activity in group 10 mmHg IPC compared to 10 mmHg. We found that the expression of bax was considerably higher in the none conditioned groups. Noticeably higher expression of anti-apoptotic bcl-2 level was measured in 10 mmHg IPC and 10 mmHg IPoC groups. In case of p53 expression: significant decrease could be seen in groups 10 mmHg IPC and 10 mmHg IPoC compared to the 10 mmHg group. CONCLUSION: Based on our results, the elevated intraabdominal pressure due to pneumoperitoneum induces oxidative stress, which is dependent on the applied pressure. Mostly precondiotioning - but also postconditioning - reduces surgical stress following laparoscopic procedures. In order to explore its mechanism it requires further investigations.

Mesenchymal stem cells transfer mitochondria into cerebral microvasculature and promote recovery from ischemic stroke.

Mesenchymal stem cells can be used as a novel treatment of ischemic stroke, but their therapeutic effect and mechanism of action require further evaluation. Mitochondrial dysfunction has core functions in ischemia-reperfusion stroke injury. Our recent research has demonstrated that mesenchymal stem cells can transfer their functional mitochondria to injured endothelial cells via tunneling nanotubes in vitro, resulting in the rescue of aerobic respiration and protection of endothelial cells from apoptosis. Therefore, we presume that the mechanisms of mitochondrial protection may be involved in stem cell-mediated rescue of injured cerebral microvasculature and recovery from ischemic stroke. In this study, the middle cerebral artery occlusion and reperfusion surgery were conducted on rats, and mesenchymal stem cells were then engrafted into the injured cerebrovascular system. Our results showed that the host cells of injured cerebral microvasculature accepted the mitochondria transferred from the transplanted stem cells, thereby resulting in significantly improving in mitochondrial activity of injured microvasculature, enhancing angiogenesis, reducing infarct volume, and improving functional recovery. Our data provided the evidence that stem cells can rescue damaged cerebrovascular system in stroke through a mechanism not yet identified.

The effect on early renal function of various dynamic preservation strategies in a preclinical pig ischemia-reperfusion autotransplant model.

The aims of this study were to determine the most optimal timing to start machine perfusion during kidney preservation to improve early graft function and to evaluate the impact of temperature and oxygen supply during machine perfusion in a porcine ischemia-reperfusion autotransplant model. The left kidney of an approximately 40-kg female Belgian Landrace pig was exposed to 30 minutes of warm ischemia via vascular clamping and randomized to 1 of 6 study groups: (1) 22-hour static cold storage (SCS) (n = 6), (2) 22-hour hypothermic machine perfusion (HMP) (n = 6), (3) 22-hour oxygenated HMP (n = 7), (4) 20-hour HMP plus 2-hour normothermic perfusion (NP) (n = 6), (5) 20-hour SCS plus 2-hour oxygenated HMP (n = 7), and (6) 20-hour SCS plus 2-hour NP (n = 6). Graft recovery measured by serum creatinine level was significantly faster for continuous HMP preservation strategies compared with SCS alone and for all end-ischemic strategies. The active oxygenated 22-hour HMP group demonstrated a significantly faster recovery from early graft function compared with the 22-hour nonactive oxygenated HMP group. Active oxygenation was also found to be an important modulator of a faster increase in renal flow during HMP preservation. Continuous oxygenated HMP applied from the time of kidney procurement until transplant might be the best preservation strategy to improve early graft function.

Alteration in gut microbiota caused by time-restricted feeding alleviate hepatic ischaemia reperfusion injury in mice.

Time-restricted feeding (TRF), that is, no caloric intake for 14-16 hours each day leads to favourable nutritional outcomes. This study is the first to investigate TRF through a surgical perspective verifying its efficacy against liver ischaemia reperfusion (I/R) injury. We randomly assigned 100 10-week-old wild-type male C57BL/6 mice into two feeding regimens: TRF and ad libitum access to food. Main outcomes were evaluated at 6, 12 and 24 hours post-I/R surgery after 12 weeks of intervention. TRF group demonstrated minor liver injury via histological study; lower serum levels of liver enzymes, glucose and lipids; higher concentrations of free fatty acid and ß-hydroxybutyrate; decreased oxidative stress and inflammatory biomarkers; as well as less severe cell apoptosis and proliferation. Further exploration indicated better gut microenvironment and intestinal epithelial tight junction function. TRF employed its positive influence on a wide spectrum of biochemical pathways and ultimately revealed protective effect against hepatic I/R injury possibly through adjusting the gut microbiota. The results referred to a strong indication of adopting better feeding pattern for surgical patients.

Adipose tissue derived mesenchymal stem cell transplantation in the treatment of ischemia/reperfusion induced acute kidney injury in rats. Application route and therapeutic window1.

PURPOSE: To evaluate renal repair in rats who had renal infarction induced by the obstruction of blood flow in the renal artery and were treated with transplantation of adipose tissue derived mesenchymal stem cell. METHODS: 16-week-old Wistar rats (n=72) were used, submitted to celiotomy and had of the renal artery and vein clipped for 24 hours. The animals were randomly assigned to 10 experimental homogeneous groups, corresponding to the treatments with phosphate-buffered saline (PBS) or adipose tissue derived mesenchymal stem cell (ADSC), duration of application (24 or 48 hours), and site of transplantation (lateral vein of the tail or intrarenal). After the treatments were performed, at 8 and 31 days, four animals in each group were subjected to left nephrectomy for histological studies. RESULTS: Histologically, a higher amount of cell debris and tubules devoid of the epithelium and a higher degree of necrosis were observed in the groups treated with PBS, as opposed to a low degree of necrosis and higher tubular vascularization in the groups treated with ADSC, particularly in the group treated with intrarenal ADSC 48 hours after injury. CONCLUSION: The transplantation of ADSC positively contributed to the replacement of necrotic tissue by renal tubular cells, vascularization of the renal parenchyma, and restoration of the organ function.

Adipose-derived stem cells alleviate liver apoptosis induced by ischemia-reperfusion and laparoscopic hepatectomy in swine.

Hepatic ischemia-reperfusion (I/R) injury is inevitable during hepatectomy and may cause both postoperative morbidity and mortality. Regenerative medicine suggested adipose-derived stem cells (ADSCs) as an attractive tool for the treatment of liver diseases. In this study, we investigated the effect of ADSCs in an I/R model combined with laparoscopic hepatectomy in swine. Eighteen Bama miniature pigs were randomly divided into Sham, IRI, and ADSCs groups. ADSCs (1 × 106/kg) were injected through liver parenchyma immediately after hemihepatectomy. The apoptosis-related role of ADSCs was studied. The results showed that ADSCs transplantation reduced both pathological and ultrastructural changes and decreased the number of apoptotic-positive cells. In the ADSCs group, Fas, Fas ligand (FasL) protein, and mRNA were downregulated and the enzyme activities of Caspase3, Caspase8, and Caspase9 were significantly decreased. In addition, ADSC therapy significantly increased the ratio of Bcl-2/Bax protein and mRNA compared to the IRI group. In conclusion, ADSCs attenuated both I/R and hepatectomy-induced liver apoptosis in a porcine model, and offers a potential therapeutic option for hepatic I/R and hepatectomy.

Adipose tissue derived mesenchymal stem cell transplantation in the treatment of ischemia/reperfusion induced acute kidney injury in rats. Application route and therapeutic window

Abstract Purpose: To evaluate renal repair in rats who had renal infarction induced by the obstruction of blood flow in the renal artery and were treated with transplantation of adipose tissue derived mesenchymal stem cell Methods: 16-week-old Wistar rats (n=72) were used, submitted to celiotomy and had of the renal artery and vein clipped for 24 hours. The animals were randomly assigned to 10 experimental homogeneous groups, corresponding to the treatments with phosphate-buffered saline (PBS) or adipose tissue derived mesenchymal stem cell (ADSC), duration of application (24 or 48 hours), and site of transplantation (lateral vein of the tail or intrarenal). After the treatments were performed, at 8 and 31 days, four animals in each group were subjected to left nephrectomy for histological studies. Results: Histologically, a higher amount of cell debris and tubules devoid of the epithelium and a higher degree of necrosis were observed in the groups treated with PBS, as opposed to a low degree of necrosis and higher tubular vascularization in the groups treated with ADSC, particularly in the group treated with intrarenal ADSC 48 hours after injury. Conclusion: The transplantation of ADSC positively contributed to the replacement of necrotic tissue by renal tubular cells, vascularization of the renal parenchyma, and restoration of the organ function.

Adipose-Derived Stem Cells Ameliorate Ischemia-Reperfusion Injury in a Rat Skin Free Flap Model.

BACKGROUND: Ischemia-reperfusion (I/R) injury is inevitable during free tissue transfers. When the period of ischemia exceeds the tissue tolerance, it causes necrosis and flap failure. The aim of this study was to investigate the effects of adipose-derived stem cells (ASCs) embedded in a collagen type I scaffold on the survival of free skin flaps to counteract I/R injury. METHODS: Left superficial caudal epigastric skin flaps (3 × 6 cm) were performed in 28 Wistar rats that were divided into four groups. The flaps elevated in the animals of the control group did not suffer any ischemic insult, and the vascular pedicle was not cut. All other flaps were subjected to 8 hours of ischemia prior to revascularization: I/R control group (8 hours of ischemia), I/R scaffold group (8 hours of ischemia + collagen type I scaffold), and I/R scaffold-ASCs group (8 hours of ischemia + collagen type I scaffold with rat ASCs embedded). Transit-time ultrasound blood flow measurements were performed. After 7 days, the areas of flap survival were measured and tissues were stained with hematoxylin/eosin and Masson's trichrome stain for histological analysis. RESULTS: The mean percentage flap survival area was significantly higher in the ASCs-treated flaps (I/R scaffold-ASCs group) compared with the ischemic controls (I/R control group and I/R scaffold group). Higher vascular proliferation and lower severity of necrosis and inflammatory changes were seen histologically in the samples of the ASCs-treated group. No significant difference in blood flow was detected between groups. CONCLUSION: Subcutaneous administration of ASCs embedded on a collagen type I scaffold reduces tissue damage after I/R injury in microvascular free flaps.

[Ruptures of popliteal artery aneurysms]. / Razryv anevrizmy podkolennoi arterii.

AIM: To improve diagnosis and surgical outcomes in patients with ruptured popliteal artery aneurysm. MATERIAL AND METHODS: Eight patients with ruptured popliteal artery aneurysm have undergone surgery for the period from 1999 to 2015 at the Vascular Surgery Department of Sklifosovsky Research Institute for Emergency Care. Incidence of rupture was 2.9% from total number of popliteal artery aneurysm. 7 patients with rupture had signs of lower limb ischemia (acute form grade I in 2 (25%) cases, grade IIA in 1 (12.5%), grade IIB in 1 (12.5%) case, chronic ischemia grade IIB in 2 (25%) patients, grade III in 1 (12.5%) patient). 1 (12,5%) patient had not lower limb ischemia. Preoperatively all patients underwent sonography of lower limb arteries and soft tissues, computed tomography of the same structures was carried out in 3 patients, 5 patients underwent subtraction digital angiography. Presence and dimensions of soft tissues hematoma, arterial perfusion proximally and distally to popliteal artery, aneurysms of contralateral limb and other localizations were assessed. RESULTS: Amputations after surgical repair were absent in 6 patients. Five patients were discharged with patent graft, completely compensated blood flow and primary healing of postoperative wound. Severe postoperative complications followed by amputation occurred in 2 patients. One patient died with reperfusion syndrome, hematoma and graft infection, sepsis. CONCLUSION: 1) Ruptured popliteal artery aneurysm is extremely rare complication, however it is a formidable event with high risk of amputation and death. 2) Early diagnosis of popliteal artery aneurysm and surgical treatment prior to embolism, thrombosis and rupture are necessary to prevent formidable complications. 3) Timely detection of aneurysms and their complications by general practitioners is extremely low due to rarity and specificity of the disease, presence of various symptoms. It is necessary to popularize knowledge about this disease among general practitioners. 4) Sonography is screening method for differential diagnosis. 5) CT-angiography or subtraction angiography are advisable to assess distal perfusion if patient's state is stable without severe ischemia. 6) Aneurysm repair with popliteal artery replacement should be performed in early period after rupture in order to reduce time of ischemia and to prevent infection of hematoma in view of ischemia and anemia.

The Optimal PEG for Kidney Preservation: A Preclinical Porcine Study.

University of Wisconsin (UW) solution is not optimal for preservation of marginal organs. Polyethylene glycol (PEG) could improve protection. Similarly formulated solutions containing either 15 or 20 g/L PEG 20 kDa or 5, 15 and 30 g/L PEG 35 kDa were tested in vitro on kidney endothelial cells, ex vivo on preserved kidneys, and in vivo in a pig kidney autograft model. In vitro, all PEGs provided superior preservation than UW in terms of cell survival, adenosine triphosphate (ATP) production, and activation of survival pathways. Ex vivo, tissue injury was lower with PEG 20 kDa compared to UW or PEG 35 kDa. In vivo, function recovery was identical between UW and PEG 35 kDa groups, while PEG 20 kDa displayed swifter recovery. At three months, PEG 35 kDa 15 and 30 g/L animals had worse outcomes than UW, while 5 g/L PEG 35 kDa was similar. PEG 20 kDa was superior to both UW and PEG 35 kDa in terms of function and fibrosis development, with low activation of damage pathways. PEG 20 kDa at 15 g/L was superior to 20 g/L. While in vitro models did not discriminate between PEGs, in large animal models of transplantation we showed that PEG 20 kDa offers a higher level of protection than UW and that longer chains such as PEG 35 kDa must be used at low doses, such as found in Institut George Lopez (IGL1, 1g/L).