Application of Adipose Stem Cells in 3D Nerve Guidance Conduit Prevents Muscle Atrophy and Improves Distal Muscle Compliance in a Peripheral Nerve Regeneration Model

BACKGROUND

Peripheral nerve injuries (PNIs) represent a significant clinical problem, and standard approaches to nerve repair have limitations. Recent breakthroughs in 3D printing and stem cell technologies offer a promising solution for nerve regeneration. The main purpose of this study was to examine the biomechanical characteristics in muscle tissue distal to a nerve defect in a murine model of peripheral nerve regeneration from physiological stress to failure.

METHODS

In this experimental study, we enrolled 18 Wistar rats in which we created a 10 mm sciatic nerve defect. Furthermore, we divided them into three groups as follows: in Group 1, we used 3D nerve guidance conduits (NGCs) and adipose stem cells (ASCs) in seven rats; in Group 2, we used only 3D NGCs for seven rats; and in Group 3, we created only the defect in four rats. We monitored the degree of atrophy at 4, 8, and 12 weeks by measuring the diameter of the tibialis anterior (TA) muscle. At the end of 12 weeks, we took the TA muscle and analyzed it uniaxially at 10% stretch until failure.

RESULTS

In the group of animals with 3D NGCs and ASCs, we recorded the lowest degree of atrophy at 4 weeks, 8 weeks, and 12 weeks after nerve reconstruction. At 10% stretch, the control group had the highest Cauchy stress values compared to the 3D NGC group (0.164 MPa vs. 0.141 MPa, p = 0.007) and the 3D NGC + ASC group (0.164 MPa vs. 0.123 MPa, p = 0.007). In addition, we found that the control group (1.763 MPa) had the highest TA muscle stiffness, followed by the 3D NGC group (1.412 MPa), with the best muscle elasticity showing in the group in which we used 3D NGC + ASC (1.147 MPa). At failure, TA muscle samples from the 3D NGC + ASC group demonstrated better compliance and a higher degree of elasticity compared to the other two groups (p = 0.002 and p = 0.008).

CONCLUSIONS

Our study demonstrates that the combination of 3D NGC and ASC increases the process of nerve regeneration and significantly improves the compliance and mechanical characteristics of muscle tissue distal to the injury site in a PNI murine model.

Hypercalcemia, an Important Puzzle Piece in Uncommon Onset Pediatric Sarcoidosis-A Case Report and a Review of the Literature

Sarcoidosis (SD) is a systemic granulomatous condition that is especially encountered in young adults and rarely in children, affecting predominantly the lungs and lymph nodes. We report the case of a 14-year-old teenage boy admitted to our clinic for nausea, vomiting, and weight loss. Clinical examination at the time of admission revealed malaise, pallor, and abdominal tenderness in the epigastric area at palpation. Laboratory tests revealed an elevated level of hemoglobin, mild thrombocytosis, increased erythrocyte sedimentation rate, and a mild increase in creatinine and urea levels along with hypercalcemia. An abdominal ultrasound revealed a right ectopic kidney, whereas the upper digestive endoscopy showed intense hyperemia and edema of the gastric mucosa. Thoracic computed tomography scan revealed giant hilar and mediastinal lymphadenopathy, along with multiple micronodules within the lung parenchyma and ground-glass aspect. The level of angiotensin-converting enzyme was high, parathormone was normal, and vitamin D level was low. Pathological examination of the bronchial, mediastinal, and lung biopsies established the diagnosis of SD. We administered oral corticosteroids for 2 months with outstandingly favorable outcome and no signs of recurrence 6 months after the cessation of the therapy.

The Postoperative Plasmatic Level of Neutrophil Gelatinase-associated Lipocalin Does not Reflect its Tissue Expression in Critically ill Patients with High Abdominal Pressure

The aim of this study was to evaluate the correlation between serum and tissue level of the Neutrophil gelatinase-associated lipocalin (NGAL), a peptide that seems to be predict the postoperative evolution of patients with high abdominal pressure. From 30 consecutive patients hospitalized in the Intensive Care Unit, we have randomly selected five cases that undergo abdominal surgical interventions, received postoperative mechanical ventilation and abdominal pressure was monitorized for at least 48 hours. In all of these cases, the plasmatic level of NGAL was measured using the Elisa method and immunohistochemical (IHC) stains with the anti-NGAL biomarker were performed in the surgically removed tissues. All of the five patients were overweight, showed high serum level of NGAL (over 950 ng/ml) and died with postoperative or septic shock. The NGAL serum level was not correlated with the abdominal pressure. No IHC positivity was observed in the examined tissues, except NGAL positivity for intravascular neutrophils. In conclusion, the postoperative high serum NGAL level may indicate unfavorable evolution. NGAL seems to be syntesized by the circulating neutrophils and its preoperative tissue expression does not reflect the serum value.

Neutrophil Gelatinase-Associated Lipocalin as a Marker for Renal Dysfunction Detection in Critically Ill Patients with Increased Intraabdominal Pressure

Introduction

Elevated intraabdominal pressure (IAP) it is known to have an impact on renal function trough the pressure transmitted from the abdominal cavity to the vasculature responsible for the renal blood flow. Intraabdominal pressure is found to be frequent in intensive care patients and also to be a predictor of mortality. Intra-abdominal high pressure is an entity that can have serious impact on intensive care admitted patients, studies concluding that if this condition progresses to abdominal compartment syndrome mortality is as high as 80%.

Aim

The aim of this study was to observe if a link between increased intraabdominal pressure and modification in renal function exists (NGAL, creatinine clearance).

Material and Method

The study enrolled 30 critically ill patients admitted in the Intensive Care Unit of SCJU TîrguMures between November 2015 and August 2016. The study enrolled adult, hemodynamically stable patients admitted in intensive critical care - defined by a normal blood pressure maintained without any vasopressor or inotropic support, invasive monitoring using PICCO device and abdominal pressure monitoring.

Results

The patients were divided into two groups based on the intraabdominal pressure values: normal intraabdominal pressure group= 52 values and increased intraabdominal group= 35 values. We compared the groups in the light of NGAL values, 24 hours diuresis, GFR and creatinine clearance. The groups are significantly different when compared in the light of NGAL values and GFR values. We obtained a statistically significant correlation between NGAL value and 24 hour diuresis. No other significant correlations were encountered between the studied items.

Conclusions

NGAL values are increased in patients with high intraabdominal pressure which may suggest its utility as a cut off marker for patients with increased intraabdominal pressure. There is a significant decreased GFR in patient with elevated intraabdominal pressure, observation which can help in early detection of renal injury in patients due to high intraabdominal pressure. No correlation was found between creatinine clearance and increased intraabdominal pressure.

Influence of Ventilation Parameters on Intraabdominal Pressure

Introduction

Intraabdominal pressure monitoring is not routinely performed because the procedure assumes some invasiveness and, like other invasive procedures, it needs to have a clear indication to be performed. The causes of IAH are various. Mechanically ventilated patients have numerous parameters set in order to be optimally ventilated and it is important to identify the ones with the biggest interference in abdominal pressure. Although it was stated that mechanical ventilation is a potential factor of high intraabdominal pressure the set parameters which may lead to this diagnostic are not clearly named.

Objectives

To evaluate the relation between intraabdominal pressure and ventilator parameters in patients with mechanical ventilation and to determine the correlation between intraabdominal pressure and body mass index.

Material and method

This is an observational study which enrolled 16 invasive ventilated patients from which we obtained 61 record sheets. The following parameters were recorded twice daily: ventilator parameters, intraabdominal pressure, SpO2, Partial Oxygen pressure of arterial blood. We calculated the Body Mass Index (BMI) for each patient and the volume tidal/body weight ratio for every recorded data point.

Results

We observed a significant correlation between intraabdominal pressure (IAP) and the value of PEEP (p=0.0006). A significant statistical correlation was noted regarding the tidal volumes used for patient ventilation. The mean tidal volume was 5.18 ml/kg. Another significant correlation was noted between IAP and tidal volume per kilogram (p=0.0022). A positive correlation was found between BMI and IAP (p=0.0049), and another one related to the age of the enrolled patients. (p=0.0045).

Conclusions

The use of positive end-expiratory pressures and high tidal volumes during mechanical ventilation may lead to the elevation of intraabdominal pressure, a possible way of reducing this risk would be using low values of PEEP and also low volumes for the setting of ventilation parameters. There is a close positive correlation between the intraabdominal pressure levels and body mass index.