Multilevel Analysis of the Neovascularization and Integration Process of a Nonvascularized Rectus Fascia Transplantation

Background

Failure to close the abdominal wall after intestinal transplantation (ITx) or multivisceral Tx remains a surgical challenge. An attractive method is the use of nonvascularized rectus fascia (NVRF) in which both layers of the donor abdominal rectus fascia are used as an inlay patch without vascular anastomosis. How this graft integrates over time remains unknown. The study aims to provide a multilevel analysis of the neovascularization and integration process of the NVRF.

Methods

Three NVRF-Tx were performed after ITx. Clinical, radiological, histological, and immunological data were analyzed to get insights into the neovascularization and integration process of the NVRF. Moreover, cryogenic contrast-enhanced microfocus computed tomography (microCT) analysis was used for detailed reconstruction of the vasculature in and around the NVRF (3-dimensional histology).

Results

Two men (31- and 51-y-old) and 1 woman (49-y-old) underwent 2 multivisceral Tx and 1 combined liver-ITx, respectively. A CT scan showed contrast enhancement around the fascia graft at 5 days post-Tx. At 6 weeks, newly formed blood vessels were visualized around the graft with Doppler ultrasound. Biopsies at 2 weeks post-Tx revealed inflammation around the NVRF and early fibrosis. At 6 months, classical 2-dimensional histological analysis of a biopsy confirmed integration of the fascia graft with strong fibrotic reaction without signs of rejection. A cryogenic contrast-enhanced microCT scan of the same biopsy revealed the presence of microvasculature, enveloping and penetrating the donor fascia.

Conclusions

We showed clinical, histological, and microCT evidence of the neovascularization and integration process of the NVRF after Tx.

Decellularized tissue exhibits large differences of extracellular matrix properties dependent on decellularization method: novel insights from a standardized characterization on skeletal muscle

Decellularized matrices are an attractive choice of scaffold in regenerative medicine as they can provide the necessary extracellular matrix (ECM) components, signals and mechanical properties. Various detergent-based protocols have already been proposed for decellularization of skeletal muscle tissue. However, a proper comparison is difficult due to differences in species, muscle origin and sample sizes. Moreover, a thorough evaluation of the remaining acellular matrix is often lacking. We compared an in-house developed decellularization protocol to four previously published methods in a standardized manner. Porcine skeletal muscle samples with uniform thickness were subjected to in-depth histological, ultrastructural, biochemical and biomechanical analysis. In addition, 2D and three-dimensional cytocompatibility experiments were performed. We found that the decellularization methods had a differential effect on the properties of the resulting acellular matrices. Sodium deoxycholate combined with deoxyribonuclease I was not an effective method for decellularizing thick skeletal muscle tissue. Triton X-100 in combination with trypsin, on the other hand, removed nuclear material but not cytoplasmic proteins at low concentrations. Moreover, it led to significant alterations in the biomechanical properties. Finally, sodium dodecyl sulphate (SDS) seemed most promising, resulting in a drastic decrease in DNA content without major effects on the ECM composition and biomechanical properties. Moreover, cell attachment and metabolic activity were also found to be the highest on samples decellularized with SDS. Through a newly proposed standardized analysis, we provide a comprehensive understanding of the impact of different decellularizing agents on the structure and composition of skeletal muscle. Evaluation of nuclear content as well as ECM composition, biomechanical properties and cell growth are important parameters to assess. SDS comes forward as a detergent with the best balance between all measured parameters and holds the most promise for decellularization of skeletal muscle tissue.

Prenatal treprostinil improves pulmonary arteriolar hypermuscularization in the rabbit model of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a congenital malformation characterized by pulmonary hypoplasia, pulmonary hypertension, and cardiac dysfunction. Pulmonary hypertension represents the major cause of neonatal mortality and morbidity. Prenatal diagnosis allows assessment of severity and selection of foetal surgery candidates. We have shown that treprostinil, a prostacyclin analogue with an anti-remodelling effect, attenuates the relative hypermuscularization of the pulmonary vasculature in rats with nitrofen-induced CDH. Here we confirm these observations in a large animal model of surgically-created CDH. In the rabbit model, subcutaneous maternal administration of treprostinil at 150 ng/kg/min consistently reached target foetal concentrations without demonstrable detrimental foetal or maternal adverse effects. In pups with CDH, prenatal treprostinil reduced pulmonary arteriolar proportional medial wall thickness and downregulated inflammation and myogenesis pathways. No effect on alveolar morphometry or lung mechanics was observed. These findings provide further support towards clinical translation of prenatal treprostinil for CDH.

The Immunoarchitecture of Human Extraocular Muscles

Purpose

The purpose of this study was to describe the immunoarchitecture of normal extraocular muscles (EOMs) in terms of presence, distribution, and organization of various immune cells.

Methods

We performed unilateral orbital exenterations in six fresh human cadavers from elderly patients, followed by dissection of the medial, lateral, superior and inferior rectus, superior and inferior oblique, and superior palpebral levator muscle in their entirety. We further cross sectioned each EOM in an anterior, central, and posterior third. After immunohistochemical staining for CD3, CD8, CD20, CD138, CD68, and podoplanin, quantitative analysis was performed.

Results

We found all EOMs (rectus, oblique, and levator muscles) to harbor both T- and B-lymphocytes, with a B-lymphocyte dominance and an absence of plasma cells. The highest prevalence of immune cells was seen in the muscle bellies, with, on average, 488 ± 63 CD3+ T-lymphocytes and 44 ± 110 CD20+ B-lymphocytes per mm2, and significant differences from the anterior (T-lymphocytes) and posterior (T- and B-lymphocytes) thirds. T- and B-lymphocytes were primarily organized in hotspots in the vicinity of blood vessels. In addition, a small resident population of macrophages scattered throughout the specimens was detected. No lymphatic vessels were found in any of the EOMs.

Conclusions

These findings can serve as a reference dataset in the assessment of EOM biopsies in the diagnostic process of inflammatory orbital and systemic disorders. Moreover, from a regenerative perspective, our results highlight the importance of taking into account the presence of a resident immune cell population when studying the host immune response on transplanted tissues or engineered constructs.

TRIT1 defect leads to a recognizable phenotype of myoclonic epilepsy, speech delay, strabismus, progressive spasticity, and normal lactate levels

TRIT1 defect is a rare, autosomal-recessive disorder of transcription, initially described as a condition with developmental delay, myoclonic seizures, and abnormal mitochondrial function. Currently, only 13 patients have been reported. We reviewed the genetic, clinical, and metabolic aspects of the disease in all known patients, including two novel, unrelated TRIT1 cases with abnormalities in oxidative phosphorylation complexes I and IV in fibroblasts. Taken together the features of all 15 patients, TRIT1 defect could be identified as a potentially recognizable syndrome including myoclonic epilepsy, speech delay, strabismus, progressive spasticity, and variable microcephaly, with normal lactate levels. Half of the patients had oxidative phosphorylation complex measurements and had multiple complex abnormalities.

OC-009 SYNGENEIC VERSUS ALLOGENEIC NON-VASCULARIZED RECTUS FASCIA TRANSPLANTATION IN A RABBIT MODEL WITHOUT IMMUNOSUPPRESSION: SHORT TERM OUTCOME

Background and aim

Transplantation (Tx) of non-vascularized rectus fascia (NVRF) is a valid option in solid organ transplant recipients to avoid open abdomen after Tx. To extrapolate this technique for non-Tx patients, we investigated in a preclinical rabbit model the feasibility of transplanting NVRF in a syngeneic (Syn) versus allogeneic (Allo) strain without using immunosuppression (IS). Short-term outcome was evaluated after 4 weeks.

Material and methods

A validated rabbit model of NVRF Tx was used comparing 6 Syn New Zealand White (NZW) rabbits versus 6 Allo Mixed breed to NZW Tx without IS. Animals were macroscopically analyzed at harvesting after 4 weeks for graft integration, herniation, adhesions, seroma, hematoma, and surgical site infections. Histological and immunohistochemical analysis was performed to assess inflammatory cell reaction and neovascularization. Mechanical testing was performed to assess the thickness, stiffness and strength.

Results

Results showed similar sufficient macroscopic ingrowth of the NVRF in both groups. At the histological level, cell infiltration suggested a clearing reaction more than a rejection-based inflammation, which was more pronounced in the Allo group. No significant differences were seen concerning mechanical properties.

Conclusions

In a validated rabbit model of NVRF Tx, we showed that Tx was possible in an Allo strain without the need for IS, resulting in satisfying short term inflammatory and mechanical outcomes. Longer-term experiments are needed to evaluate the effect of graft integration and possible hernia development.

Use of right ventricular pressure increase rate to evaluate cardiac contractility in horses

OBJECTIVE

To establish reference values for right ventricular maximal rate of increase in pressure (dP/dt(max)) in horses and determine the usefulness of this variable to evaluate cardiac contractility.

ANIMALS

15 crossbred horses, 3 to 20 years old.

PROCEDURE

Cardiac catheterization was performed, using a high-fidelity catheter tip micromanometer, to determine right ventricular dP/dt(max). The following mathematic corrections were made: for preload, (dP/dt(max))/instantaneous total pressure, (dP/dt(max))/instantaneous developed pressure, and (dP/dt(max))/end diastolic pressure; for afterload, (dP/dtCPIP)/common peak isovolumic pressure. Wedge pressure was measured simultaneously, using a Swan-Ganz catheter. A negative inotropic drug, detomidine hydrochloride, was administered to 6 horses to examine the effect of the negative inotropic drug on right ventricular dP/dt(max) and derived variables.

RESULTS

The mean right ventricular dP/dt(max) was 477 (+/- 84.1) mm Hg/s in 15 horses. A 40% decrease in dP/dt(max) was found for 30 minutes after detomidine administration. Variables that correct for preload and afterload were influenced similarly. Detomidine administration also caused a 24% increase in mean wedge pressure, probably indicating reduced left-sided cardiac contractility.

CONCLUSIONS AND CLINICAL RELEVANCE

Right ventricular dP/dt(max) may be a useful clinical variable for determining acute changes in cardiac contractility in horses.

The use of non-immune plasma powder in the prophylaxis of neonatal Escherichia coli diarrhoea in calves

The protective use of plasma powder from cattle and swine against experimentally induced neonatal E. coli diarrhoea in colostrum-deprived calves was examined. Diarrhoea was induced with a strain expressing F5+ fimbriae and a strain expressing F17+ fimbriae. In all groups supplemented with bovine plasma powder, diarrhoea and fever were less severe than in the control groups. For the groups infected with the F5+ E. coli strain, a reduction in excretion of the challenge strain by 2-4 orders of magnitude and by 1-2 orders of magnitude was seen when supplemented with bovine plasma powder at a dose of 25 g/l milk and 10 g/l milk, respectively. The bovine plasma powder showed also beneficial effects in the F17+ infected groups. No mortality, no septicaemia and no severe clinical signs were observed. Concerning the excretion of the E. coli F17+ strain in the faeces, no significant difference with the control group was found. Swine plasma powder showed little beneficial effect on E. coli diarrhoea in calves in this study.

Protection of just weaned pigs against infection with F18+ Escherichia coli by non-immune plasma powder

The anti-colonization effect of porcine plasma powder against experimentally induced postweaning diarrhoea and oedema disease in just weaned piglets was examined. Piglets were infected with an Escherichia coli strain expressing F18ac fimbriae and producing SLTIIv- and LT-toxins. Reduced fecal excretion of the challenge strain and protection against clinical symptoms was obtained by daily supplementation of the feed with either 90 or 45 g of plasma powder. However, the piglets receiving 90 g of plasma powder a day showed diarrhoea and reduced weight gain compared to the piglets receiving 45 g of plasma powder a day. The diarrhoea was attributed to biogenic amines released from excessive protein in the diet.

Intracardiac overdrive pacing as a treatment of atrial flutter in a horse

A five-year-old warmblood mare with atrial fibrillation was treated with quinidine sulphate. The atrial rhythm changed to atrial flutter and, because there were toxic effects, the treatment was discontinued. Seven months after the occurrence of the atrial flutter, treatment with a rapid atrial pacing technique restored a normal sinus rhythm. One year after the pacing therapy the horse was still in sinus rhythm and had been brought back into training.

Effect of inhaled nitric oxide on the hypoxic pulmonary vasoconstrictor response in anaesthetised calves

The effect of inhaling nitric oxide in the hypoxic pulmonary vascular response was measured in five calves anaesthetised with a combination of guaiacol, ketamine and xylazine. Alveolar hypoxia was induced by means of the inhalation of a gas mixture with an inspiratory oxygen fraction of 14-18 per cent. This alveolar hypoxia resulted in a pronounced pulmonary hypertension (mean pulmonary artery pressure in hypoxic animals: 30.2 mmHg). Inhalation of 20 and 40 ppm of nitric oxide significantly attenuated the hypoxia induced pulmonary hypertension. The effect ceased once nitric oxide administration was stopped. A concentration of 40 ppm of nitric oxide fully abolished the hypoxia induced pulmonary hypertension (mean pulmonary artery pressure during inhalation of 40 ppm nitric oxide: 22.8 mmHg). Inhalation of nitric oxide had no effect on systemic arterial blood pressure nor on systemic vascular resistance. It was concluded that inhalation of 20 or 40 ppm of nitric oxide prevented a selective pulmonary vasoconstriction during alveolar hypoxia in calves, which may be helpful in the treatment of acute respiratory disorders in calves.

Efficacy of the combination sodium ceftiofur-flumethasone in the treatment of experimental Pasteurella haemolytica bronchopneumonia in calves

Severe acute bronchopneumonia was induced in 18 conventional Friesian-Holstein calves by inoculating them intratracheally with Pasteurella haemolytica type A1. Six of the calves received no treatment and served as controls. Six of the calves were treated with sodium ceftiofur and six were treated with sodium ceftiofur and flumethasone. The mortality rate in the group of calves treated with sodium ceftiofur and flumethasone was significantly lower and their clinical and haematological parameters returned to normal significantly faster than in the control calves and the calves treated with sodium ceftiofur alone.

Effect of the inhalation of nitric oxide on 5-hydroxytryptamine-induced pulmonary hypertension in calves

In healthy anaesthetized Friesian-Holstein calves, pulmonary hypertension was induced by means of a continuous intravenous administration of serotonin (0.025 mg/kg body/weight/min). Afterwards, the anaesthetized calves inhaled 40 and 80 ppm of nitric oxide using an open system. The influences of the administration of serotonin and the inhalation of nitric oxide on the haemodynamic and blood gas parameters were investigated. The inhalation of 40 and 80 ppm of nitric oxide during serotonin-induced pulmonary hypertension in calves resulted in a significant fall of the mean pulmonary artery pressure. The inhalation of nitric oxide also induced an amelioration of intrapulmonary oxygen transport. The intravenous administration of serotonin in calves resulted in severe systemic hypotension. Hence, the influence of the inhalation of nitric oxide on the systemic arterial pressure could not be evaluated.

Evaluation of the nebulisation of sodium ceftiofur in the treatment of experimental Pasteurella haemolytica bronchopneumonia in calves

Severe acute bronchopneumonia was induced in 24 conventional Friesian Holstein calves by inoculating them intratracheally with Pasteurella haemolytica type A1. Twelve of the calves were treated intramuscularly with sodium ceftiofur and 12 were treated with an aerosol of sodium ceftiofur. The mortality rate in the group of calves treated with the aerosol was significantly lower, and their clinical and haematological parameters returned to normal significantly faster than in the calves treated intramuscularly.

Larval cyathostomiasis as a cause of death in two regularly dewormed horses

Two horses were presented with complaints of chronic weight loss and subcutaneous oedema, one of them presenting diarrhoea. Both animals were grazed with other unaffected horses, all of them being regularly dewormed. Blood chemistry revealed hypoalbuminaemia and a low albumin-globulin ratio. Faecal egg counts were negative and no cyathostome larvae could be found in the faeces. Neither of these horses could be saved, despite intensive treatment. Postmortem examination revealed severe typhlitis and colitis due to numerous inhibited cyathostome larvae.

Evaluation of the effect of 3 probiotics on experimental Escherichia coli enterotoxaemia in weaned piglets

In this report the efficacy of 3 different probiotics (Bacillus cereus "toyoi", Lactobacillus spp. and Streptococcus faecium) was investigated. They were supplemented in the food of recently weaned piglets that were orally infected with E. coli O141 K85ab. Supplementation could not prevent mortality and clinical symptoms nor reduce the faecal excretion of hemolytic E. coli. The possible explanations for the unsatisfying results are various.

Efficacy of tilmicosin in treatment of pulmonary infections in calves

The efficacy of tilmicosin in the treatment of respiratory infections in calves was evaluated. According to a randomised block design, 58 calves with naturally occurring respiratory infections were treated with one of the following products: a single subcutaneous injection of tilmicosin (10 mg/kg liveweight) or daily intramuscular injections of 5 mg lincomycin and 10 mg spectinomycin/kg liveweight, for a minimum of three days. Both treatment groups initially showed similar clinical signs and their initial responses to the treatments were good. However, the tilmicosin treated calves improved more rapidly. Significantly greater improvements (P less than or equal to 0.05) were observed in their demeanour and appetite during the first 10 days after treatment began, and in their respiratory condition between five and 10 days after treatment began.

Horner's syndrome in the horse: a clinical, experimental and morphological study

A clinical case of Horner's syndrome is described in a Standardbred horse, and the various symptoms of cranial sympathetic denervation are studied in two ponies after experimental transection of the left cervical sympathetic trunk and vagosympathetic trunk, respectively. The most prominent symptoms of equine Horner's syndrome were ptosis, local sweating and increased cutaneous temperature in the denervated area. Enophthalmos, miosis and increased lacrimation were also observed but these symptoms were mild, variable and difficult to ascertain. Prolapse of the third eyelid was not noticed. Concomitant laryngeal hemiplegia was present in the clinical case and was provoked experimentally in one pony by transection of the left vagosympathetic trunk. The aetiology of each of these symptoms is discussed by comparing the results of pharmacological tests and histological findings in the three horses with the data from the literature.

Biochemical profiles in cows with abomasal displacement estimated by blood and liver parameters

The metabolic status of normal lactating cows and of cows suffering from abomasal dilatation was evaluated by examination of blood parameters and by determination of the fat and glycogen content in liver biopsies. The method for examination of the liver biopsies is described. In clinically normal lactating cows the liver contains less than 20 mg triglycerides (TG) and more than 20 mg glycogen per gram of wet tissue. Cows suffering from abomasal displacement all showed hyperglycemia and in most of them a fatty to very fatty liver was found. The degree of hyperglycemia depends on the amount of liver glycogen and is independent of the liver TG content. The degree of ketonemia also depends on the liver glycogen content.

The influence of clenbuterol on prostaglandin F2 alpha-induced dyspnoea in calves

Pulmonary function tests were performed in six healthy calves. Prostaglandin F2 alpha causes severe narrowing of both upper and lower airways (total lung resistance increased, dynamic compliance decreased). Clenbuterol administered intravenously fifteen minutes prior to prostaglandin F2 alpha aerosol, and in increasing doses (0, 0.4, 0.8, 1.2 micrograms/kg), on days 1, 2, 4 and 6 of the experiment, effectively but not entirely suppressed these responses. These data indicate that beta-adrenergic receptors are present in the bovine airways and that the use of clenbuterol (0.8 micrograms/kg) may be effective in treating clinical respiratory disease such as bronchopneumonia in calves.

The effect of clenbuterol on lung function parameters in calves suffering from bronchopneumonia

Pulmonary function testing was performed in calves affected with bronchopneumonia. In these calves respiratory rate, viscous work per litre air and per minute, intrapleural pressure difference, mean inspiratory and expiratory flow rate and ventilation per minute were significantly increased. Total resistance of the lung was just not significantly increased. Dynamic compliance and tidal volume were significantly reduced. The main effect of clenbuterol was a significant increase in dynamic compliance. The reduction in the total resistance of the lung was just not significant. These results indicate that clenbuterol can antagonise, at least partly, the alterations caused by bronchopneumonia.

The influence of the administration of sow's milk on the post-weaning excretion of hemolytic E. coli in the pig

The postweaning excretion rate of hemolytic E. coli was determined in piglets from herds affected with edema disease and on control farms. No distinct difference in rate of excretion was observed. A split litter trial was set up to evaluate the importance of sow's milk in the postweaning rise of fecal hemolytic E. coli. 525 ml of sow's milk a day, mixed with the feed, completely inhibited that postweaning rise, even after oral challenge with a pathogenic strain.

Potassium concentration in equine red blood cells: normal values and correlation with potassium levels in plasma

The concentration of potassium in plasma and in red blood cells was determined in 948 horses. The coefficient of correlation between the two parameters was low. In 436 of these horses, which were clinically healthy, the red blood cell potassium (RBCK+) levels did not fit within a normal distribution curve, but a bimodal distribution was observed with a section point at 90 mmol/litre. In 90 per cent of these normal horses, mean RBCK+ content was 97.5 mmol/litre. In the remaining 10 per cent, mean RBCK+ concentration was 93.8 mmol/litre. A subdivision into a 'low potassium group' and a 'high potassium group' was made. In 10 out of 15 horses in the 'low potassium group', bimonthly sampling over a period of one year showed that RBCK+ content remained low. In the remaining five horses an increase was observed.

Determination of red blood cell potassium content in horses with diarrhoea: a practical approach for therapy

The concentration of potassium in the red blood cells in 15 horses with severe diarrhoea was determined. The red blood cell potassium content (RBCK+) was low compared with levels obtained in normal horses. The decrease in the RBCK+ was used to evaluate the total body potassium deficit. This calculated amount was administered orally, following each RBCK+ determination. In those horses which recovered, RBCK+ content returned to normal levels. During treatment, refilling of the red blood cells with potassium occurred only gradually as long as the diarrhoea persisted. In each case, oral loading with the calculated dose resulted in an improvement of the general condition and no side effects were observed. The importance of using RBCK+ levels as a diagnostic and therapeutic parameter is discussed.