Bone marrow-derived mesenchymal stromal cells and platelet-rich plasma on a collagen matrix to improve fascial healing.

OBJECTIVE: To demonstrate improved healing of a midline laparotomy after application of mesenchymal stromal cells and platelet-rich plasma on a collagen matrix and introduce a potential cellular-based therapy for the prevention of incisional hernia formation. BACKGROUND: Up to 10 % of laparotomies are complicated by postoperative incisional hernias. Despite continuous improvements in surgical technique and technology, hernia rates have remained constant. Cell-based therapies focused on augmentation of the body's natural healing properties could reduce hernia formation. METHODS: Midline laparotomies were performed on 42 Lewis rats. Three groups were studied: (1) primary repair only, (2) primary repair with CollaTape™ (CoTa) overlay and platelet-rich plasma (PRP), and (3) primary repair with CoTa overlay and PRP and bone marrow-derived mesenchymal stromal cells (BM-MSCs). Abdominal wall fascia was recovered at 4 and 8 weeks in each group. Biomechanical testing and histological evaluation was performed. RESULTS: At 4 weeks, there was a twofold increase in tensile strength between groups 1 and 2 and a fourfold increase between groups 1 and 3 (p < 0.001). Group 3 had a 320 % increase in total energy absorption at 4 weeks compared to group 1 and a 142 % increase at 8 weeks (p < 0.001). Vascularization and collagen abundance were significantly increased in group 3 at both time points. CONCLUSION: The addition of BM-MSCs, PRP, and CoTa led to a marked improvement in abdominal wall strength and energy absorption. Histologic evaluation confirmed increased vascularity and collagen abundance consistent with the biomechanical findings. Application of this therapy may ultimately reduce incisional hernia formation.

Sensitizing stimulation causes a long-term increase in heart rate in Aplysia californica.

These studies show that cutaneous stimulation that evoked body wall contraction elicited a concurrent disruption of cardiovascular function. A pinch or test shock to the tail caused a 10- to 30-s increase in diastolic pressure and variability in pulse pressure. Sensitizing cutaneous stimulation which produced enhancement of the tail withdrawal reflex caused no enhancement of the evoked cardiovascular responses. At 20 min post-sensitization training a gradual increase in heart rate was observed and at 60 min post-sensitization training, heart rate was 111 +/- 4.3% presensitization values. These long-term changes in cardiovascular function appear to be mediated by the central nervous system. Chemical blockade of conduction at P9 or the pleural-abdominal connectives prevented the sensitization-induced increase in heart rate.

Humoral factors released during trauma of Aplysia body wall. I. Body wall contraction, cardiac modulation, and central reflex suppression.

1. Mechanical or electrical stimulation of isolated sections of body wall produced contractions that were graded with the intensity of the stimulus. Injury of body wall with shallow incisions produced extremely persistent contractions. 2. Long-lasting contraction of isolated body wall was also produced by brief application of "stimulated body wall wash" (SBW), sea water which was first washed through another section of body wall subjected to intense mechanical or electrical stimulation. Contractions were produced by SBW diluted to concentrations as low as 1% of the initial concentration. Contractions produced by prolonged application of SBW showed little fatigue, tachyphylaxis, or desensitization. 3. SBW caused contraction of isolated sections of body wall from all regions of the body, including tail, parapodia, siphon, purple gland, rhinophores, and anterior tentacles. SBW also caused contraction of isolated lateral columellar muscle and of the gill. 4. 30 mM CoCl2 blocked the release of contractile factors into electrically stimulated body wall and reduced but did not abolish contractile responses of unstimulated body wall to perfused SBW. SBW contractions were unchanged by disconnection of the perfused tissue to the CNS. 5. Hemolymph collected from the neck of an intact donor following strong electrical stimulation of the tail or excision of a parapodium ('stimulated hemolymphh, SHL) caused long-lasting contractions which were larger than those produced by control hemolymph (CHL) collected prior to stimulation of the donor. 6. Similarities between body wall contractions produced by SHL and by SBW, including their occurrence in 30 mM CoCl2, suggest that some of the contractile activity in SHL may be directly released from traumatized body wall. 7. SHL caused significantly greater cardioacceleration of the isolated heart than did CHL. Similarities between the cardioacceleration produced by SHL and by SBW suggest that a source of cardiac activity in SHL may be traumatized body wall. 8. SBW suppressed the gill-withdrawal reflex when applied selectively to the sheathed or desheathed abdominal ganglion. SBW-induced suppression was associated with significant reduction of evoked spike activity in identified gill motor neurons. SHL collected 1-2 h after noxious stimulation caused weak but significant suppression of the gill-withdrawal reflex when applied to the fully sheathed abdominal ganglion.

Humoral factors released during trauma of Aplysia body wall. II. Effects of possible mediators.

1. Preliminary, general chemical characteristics of substances in artificial sea water (ASW) washed through stimulated body wall (SBW) and in hemolymph taken from noxiously stimulated animals (SHL) were consistent with those of classical neurotransmitters, amino acids, and small- to medium-sized peptides. 2. 5-Hydroxytryptamine (5HT) and acetylcholine (ACh), unlike SBW and SHL, caused relaxation when perfused into isolated body wall. FMRFamide produced a biphasic response--brief contraction followed by prolonged relaxation. 3. Small cardioactive peptide (SCPB) caused body wall contractions similar to those produced by SBW and SHL, except that SCPB contractions displayed more desensitization and were completely blocked by 30 mM CoCl2. SCPB and SBW contractions were synergistic. 4. Dopamine caused persistent body wall contractions similar to those of SBW and SHL. Dopamine contractions were reduced but not blocked by 30 mM CoCl2. Unlike SBW activity, dopamine activity was reduced by alkalinization. 5. Glutamate and taurine produced strong but usually short-lasting body wall contractions. Adenosine, octopamine, arginine vasotocin, and cholecystokinin (CCK-8) caused weak or variable contractions. Met-enkephalin and somatostatin caused no obvious body wall responses. 6. When superfused over the fully sheathed abdominal ganglion, FMRFamide, met-enkephalin, glutamate, aspartate, and taurine reduced the magnitude of the gill-withdrawal reflex elicited by siphon nerve stimulation. 7. Taken together with earlier results, these data suggest a preliminary framework for trauma signal pathways. It is proposed that stress hormones (perhaps including FMRFamide, SCPs, 5HT, and dopamine) are released into hemolymph from neuroendocrine cells. Effective amounts of active intracellular solutes such as amino acids may also be released by extensive cellular rupture. Various humoral signals produce slow effects that contribute to hemostasis, balling up, increased cardiac output, and reflex suppression.

Brain renin: localization in rat brain synaptosomal fractions.

The distribution of brain renin activity was determined in subcellular fractions of rat brain prepared by discontinuous density gradient centrifugation. The highest amounts of brain renin activity occurred in both the light and heavy synaptosomal fractions, while the activity of choline acetyltransferase was elevated only in the light synaptosomal fraction. These results indicate an intraneuronal localization of brain renin.