Generation and characterization of highly purified canine Schwann cells from spinal nerve dorsal roots as potential new candidates for transplantation strategies

Schwann cells are promising candidates for transplantation strategies in the central nervous system by promoting axonal regeneration. The dog represents a translational model for human spinal cord injury (SCI) for studies with new repair strategies after intervertebral disk herniation (IVDH). To overcome the necessity for an additional surgical procedure, for the first time a protocol for the isolation and purification of canine Schwann cells from spinal nerve biopsies during standard hemilaminectomy in IVDH‐affected paraplegic dogs for potential transplantation has been developed. Purity was assessed by flow cytometry. The results were compared with biopsies from dogs without SCI. Within 26 ± 4 days, 90.2 ± 8.8% p75 neurotrophin receptor (p75^NTR)‐positive cells were achieved in IVDH dogs. The total cell count in acute/subacute and chronic IVDH (acute/subacute: 6.82 ± 6.36 × 10⁶; chronic: 2.29 ± 2.00 × 10⁶) differed significantly (p = 0.0120) at the potential time point of transplantation. No differences in culture period and purity were detected between dogs with and without IVDH. Despite the small sample size and the altered environment, the isolation of Schwann cells was successful. Negative influences on isolation and purification due to potential pathological changes at the biopsy site of IVDH‐diseased dogs were ruled out by comparison of Schwann cell pellets from diseased and control dogs. Finally, the functionality of Schwann cells from dogs with IVDH was outlined in co‐culture experiments with canine dorsal root ganglion neurons. In conclusion, nerve root biopsies provide a sufficient number of highly purified and functional Schwann cells within a useful time period for novel therapeutic strategies in dogs with SCI.     

Increased brain l‐arginine availability facilitates cutaneous heat loss induced by running exercise

The effects of increased brain availability of l ‐arginine (l ‐arg), a precursor for nitric oxide synthesis, on core body temperature (T_core) and cutaneous heat loss were evaluated in running rats. One week prior to the experiments, adult male Wistar rats received the following implants: a chronic guide cannula in the lateral cerebral ventricle and a temperature sensor in the abdominal cavity. On the day of the experiments, the rats were assigned to receive a 2‐μL intracerebroventricular injection of either NaCl (0.15 mol/L) or l ‐arg solution (0.825, 1.65 or 3.30 mol/L); T_core and tail skin temperature were measured while the rats ran at a speed of 18 m/min until they were fatigued. l ‐arginine induced a dose‐dependent reduction in the threshold T_core required for cutaneous heat loss (38.09 ± 0.20°C for 3.30‐mol/L l ‐arg vs 38.61 ± 0.10°C for saline; P < 0.05), which attenuated the exercise‐induced hyperthermia. Although the rats treated with l ‐arg presented a lower T_core at the end of exercise (~0.7°C lower after treatment with the highest dose), no changes in the time to fatigue were observed relative to the control trial. These results suggest that brain l ‐arg controls heat loss during exercise, most likely by modulating the sympathetic vasoconstrictor tonus to skin vessels. Furthermore, despite facilitating cutaneous heat loss mechanisms, increased brain l ‐arg availability did not enhance physical performance.     

Osteoinductive 3D scaffolds prepared by blend centrifugal spinning for long-term delivery of osteogenic supplements

Bone regeneration is a long-term process requiring proper scaffolding and drug delivery systems. The current study delivers a three-dimensional (3D) scaffold prepared by blend centrifugal spinning loaded with the osteogenic supplements (OS) β-glycerol phosphate, ascorbate-2-phosphate and dexamethasone. The OS were successfully encapsulated into a fibrous scaffold and showed sustained release for 30 days. Furthermore, biological testing showed the osteoinductive properties of the scaffolds on a model of human mesenchymal stem cells and stimulatory effect on a model of osteoblasts. The osteoinductive properties were further proved in vivo in critical size defects of rabbits. The amount of bone trabecules was bigger compared to control fibers without OS. The results indicate that due to its long-term drug releasing properties, single step fabrication process and 3D structure, the system shows ideal properties for use as a cell-free bone implant in tissue-engineering.

Bone regeneration is a long-term process requiring proper scaffolding and drug delivery systems.     

Effect of blood passage through the pulmonary circulation on fibrinolytic parameters

The lung vasculature bed has a unique fibrinolytic potential, which has not yet been completely elucidated. We investigated the effect of blood passage through the pulmonary circulation on the values of fibrinolytic parameters in plasma. Forty-seven patients (16 women, 31 men, mean age 54 years, range 21–67 years) who had undergone elective cardiac catheterization were included in the study. The blood samples were taken simultaneously from the right atrium and the left ventricle. The following fibrinolytic parameters were measured: tissue-type plasminogen (t-PA) antigen and activity, plasminogen activator inhibitor-1 (PAI-1) antigen and activity, and euglobulin clot lysis time (ECLT). No difference was found between the samples obtained from the right atrium and the left ventricle with respect to t-PA antigen: 8.1 (6.7–11.3) vs 8.4 (5.9–11.0)ng/ml; t-PA activity: 92 (5–680) vs 62 (32–696)IU/ml; PAI-1 antigen: 8.4 (5.5–14.3) vs 8.7 (6.2–13.1)ng/ml; and ECLT: 5.5 (4.1–9.1) vs 5.6 (4.1–8.5) 1000/min. In contrast, PAI activity decreased significantly: 7.9 (5.8–10.3) vs 7.4 (6.0–10.4)IU/ml, P 0.01. Patients with and without pulmonary hypertension did not differ in any of measured parameters, either in the right atrium or in the left ventricle. These results show that under basal conditions fibrinolytic activity which is not attributed to t-PA is elevated in lung vasculature. Further, basal fibrinolytic activity in the lungs is not influenced by pulmonary hypertension.     

Serum carnitine levels and carnitine esters of patients after kidney transplantation: role of immunosuppression

Serum levels of carnitine and carnitine esters were measured in different groups of patients after cadaveric renal transplantation and compared with those of healthy subjects as well as azotemic and uremic patients. In all groups of patients serum levels of total carnitine (TC), free carnitine (FC), short-chain acylcarnitine (SCC), and long-chain acylcarnitine (LCC) increased with reduction of kidney function. However, cyclosporin- and prednisone-treated transplant patients with impaired kidney function displayed significantly higher TC, FC, and SCC compared with transplant patients under immunosuppression with azathioprine and prednisone. This group of cyclosporin-treated patients showed also significantly elevated serum cholesterol suggesting that carnitine deficiency is not responsible for the observed abnormalities in lipid metabolism after renal transplantation. Urinary excretion of TC, FC, SCC, and LCC decreased with reduction of kidney function without differences between cyclosporin- and azathioprine-treated patients. Single dose L-carnitine administration (10 mg/kg body weight IV) resulted in significantly higher TC, FC, SCC, and LCC values of azotemic patients with and without immunosuppression than in healthy subjects. Acylation of the administered carnitine was comparable in healthy controls and azotemic patients. Increased values of short-chain and long-chain acylcarnitine, therefore, seem to depend on the excretion of the diseased kidney(s). Our data demonstrate abnormalities in carnitine metabolism in patients with impaired kidney function. These alterations are further influenced by immunosuppressive drugs.     

A new two‐dimensional sonographic approach to the assessment of the fetal hard and soft palates

Facial clefts are among the most common congenital defects. Ultrasound (US) imaging of secondary fetal palate, especially the detection of isolated defects, remains challenging. Currently described two‐dimensional (2D) and three‐dimensional methods are technically demanding and impractical for application during routine fetal anatomy evaluation. As an adjunct method, magnetic resonance imaging can provide additional information but has its limitations. We present a novel 2D US approach using axial and sagittal planes to evaluate the fetal palate and demonstrate the main differences between an intact palate, isolated cleft palate, and a cleft lip with cleft palate.