Stent oder Chirurgie beim Pankreaskarzinom

Dose-response relationship of mesenchymal stem cell transplantation and functional regeneration after severe skeletal muscle injury in rats

Various therapeutic strategies that aim to influence clinical outcome after severe skeletal muscle trauma have been considered. One such method, the local transplantation of stem cells, has been shown to improve tissue regeneration. The number of cells required for successful regeneration, however, remains unclear. The aim of this study was therefore to examine the correlation between the number of transplanted bone marrow-derived mesenchymal stem cells (MSCs) and the resulting muscle function. One week after inducing an open crush trauma in 34 female Sprague Dawley rats, increasing quantities of autologous MSCs (0.1 x 10(6), 1 x 10(6), 2.5 x 10(6), and 10 x 10(6) cells) or saline solution (control group) were transplanted into the left soleus muscle of the rat hind limb. At 4 weeks posttrauma, the outcome was assessed by measuring muscle contraction forces following an indirect fast twitch and tetanic stimulation. A logarithmic dose-response relationship was observed for both maximum twitch and tetanic contraction forces (R(2) = 0.9 for fast twitch [p = 0.004]; R(2) = 0.87 [p = 0.002] for tetanic contraction). The transplantation of 10 x 10(6) cells resulted in the most pronounced improvement of muscle force. MSC therapy represents a promising new tool for the treatment of skeletal muscle trauma that shows potential for aiding in the prevention of severe functional deficiencies. The logarithmic dose-response relationship demonstrates the association between the number of transplanted cells and the resulting muscle forces, as well as the amount of MSCs required for promoting muscular regeneration.

Influence of fiber-type composition on recovery from tourniquet-induced skeletal muscle ischemia-reperfusion injury

This study was designed to determine if previously reported differences in the functional impairment of muscles composed of predominantly different fiber types occurs following extended periods of ischemia. We hypothesized that the soleus (Sol) muscle, a predominantly slow-twitch muscle, would be less vulnerable to tourniquet-induced ischemia-reperfusion than the plantaris (Plant), a predominantly fast-twitch muscle, as determined by the assessment of isometric contractile function. Male Sprague-Dawley rats were assigned to one of the following groups to undergo tourniquet application (TKA) (n = 6/group): 2 h TKA, 2 d recovery; 4 h TKA, 2 d recovery; 2 h TKA, 14 d recovery; or 4 h TKA, 14 d recovery. In situ isometric contractile properties were assessed in the predominantly slow-twitch Sol and the predominantly fast-twitch Plant; the contralateral muscle served as the internal control. At 2 d, muscle contraction could not be elicited via neural stimulation, but muscles did contract with direct stimulation, which indicates neural injury. This condition was resolved by day 14. At this time point, tetanic tension (Po) in the Plant was reduced by 45% and 69% in the 2 and 4 h groups, respectively. Po for the Sol was unaffected in the 2 h group, but was reduced by 30% in the 4 h group. The fatigue resistance of the Plant was increased 2 fold in the 4 h group and was unchanged in all other groups. These results demonstrate that vulnerability to tourniquet-induced ischemia-reperfusion injury is dramatically different with respect to muscle fiber-type composition.

Autologous Bone Marrow-Derived Cells Enhance Muscle Strength Following Skeletal Muscle Crush Injury in Rats

Insufficient post-traumatic skeletal muscle regeneration with consecutive functional deficiency continues to be a serious problem in orthopedic and trauma surgery. Transplantation of autologous muscle precursor cells has shown encouraging results in muscle trauma treatment but is associated with significant donor site morbidity. In contrast to this, bone marrow-derived (BMD) cells can be obtained without any functional deficit by puncture. The goal of this study was to examine whether regular muscle regeneration can be improved by local application of autologous BMD cells in a rat model of blunt skeletal muscle trauma. One week after standardized open blunt crush injury to the left soleus muscle, 10(6) autologous BMD cells were injected into the traumatized muscle of male Sprague Dawley rats. Rats of the control group received saline solution as treatment. Three weeks after application, the fast twitch and tetanic contraction capacity of the soleus muscles was measured bilaterally by stimulating the sciatic nerves. Contraction forces of injured soleus muscles in control animals recovered to 39 +/- 10% (tetanic) and 59 +/- 12% (fast twitch) of the contralateral noninjured soleus muscles (p < 0.001). In contrast, autologous BMD cell injection significantly restored contractile forces to 53 +/- 8% (tetanic) and 72 +/- 13% (fast twitch) compared to those observed in contralateral noninjured soleus muscles. Thus, muscle function was significantly increased by BMD cell treatment (tetanic, p = 0.014; fast twitch, p = 0.05). In conclusion, autologous BMD cell grafting leads to an increase in contraction force, 14% in tetanic and 13% in fast twitch stimulation, demonstrating its potential to improve functional outcome after skeletal muscle crush injury.