Histamine release and fibrinogen adsorption mediate acute inflammatory responses to biomaterial implants in humans

<p>Abstract</p> <p>Background</p> <p>Medical implants often fail as a result of so-called foreign body reactions during which inflammatory cells are recruited to implant surfaces. Despite the clinical importance of this phenomenon, the mechanisms involved in these reactions to biomedical implants in humans are not well understood. The results from animal studies suggest that both fibrinogen adsorption to the implant surface and histamine release by local mast cells are involved in biomaterial-mediated acute inflammatory responses. The purpose of this study was to test this hypothesis in humans.</p> <p>Methods</p> <p>Thirteen male medical student volunteers (Caucasian, 21–30 years of age) were employed for this study. To assess the importance of fibrinogen adsorption, six volunteers were implanted with polyethylene teraphthalate disks pre-coated with their own (fibrinogen-containing) plasma or (fibrinogen-free) serum. To evaluate the importance of histamine, seven volunteers were implanted with uncoated disks with or without prior oral administration of histamine receptor antagonists. The acute inflammatory response was estimated 24 hours later by measuring the activities of implant-associated phagocyte-specific enzymes.</p> <p>Results</p> <p>Plasma coated implants accumulated significantly more phagocytes than did serum coated implants and the recruited cells were predominantly macrophage/monocytes. Administration of both H1 and H2 histamine receptor antagonists greatly reduced the recruitment of macrophages/monocytes and neutrophils on implant surfaces.</p> <p>Conclusion</p> <p>In humans – as in rodents – biomaterial-mediated inflammatory responses involve at least two crucial events: histamine-mediated phagocyte recruitment and phagocyte accumulation on implant surfaces engendered by spontaneously adsorbed host fibrinogen. Based on these results, we conclude that reducing fibrinogen:surface interactions should enhance biocompatibility and that administration of histamine receptor antagonists prior to, and shortly after, medical device implantation should improve the functionality and longevity of medical implants.</p

Phagocyte accumulation on the surfaces of PET disks implanted in volunteers with and without the treatment of H1 and H2 histamine receptor antagonists

<p><b>Copyright information:</b></p><p>Taken from "Histamine release and fibrinogen adsorption mediate acute inflammatory responses to biomaterial implants in humans"</p><p>http://www.translational-medicine.com/content/5/1/31</p><p>Journal of Translational Medicine 2007;5():31-31.</p><p>Published online 1 Jul 2007</p><p>PMCID:PMC1929055.</p><p></p> (A) Myeloperoxidase and non-specific esterase activities were measured to reflect the degree of accumulation of PMN and MØ, respectively. (B) The estimated numbers of adherent PMN, MØ, and total phagocytes (PMN+ MØ) are calculated. Vertical lines denote ± 1 Standard Deviation. Significance vs. control volunteers (without antagonists): * p < 0.05

Pros and Cons of Early and Late Skin Grafting in Children with Burns—Evaluation of Common Concepts

Background: There is no consensus regarding the timing of surgery in children with smallerburn size, specifically in deep dermal burns. Delayed surgery has risks in terms of infection anddelayed wound healing. Early surgery also risks the removal of potentially viable tissue. Our aim wasto investigate the effect of the timing of surgical intervention on the size of the area operated on andthe time to wound healing. Methods: A retrospective analysis for all children (&lt;18 years) with burnsize &lt;20% body surface area (BSA%) during 2009–2020 who were operated on with a split-thicknessskin graft. The patients were grouped by the timing of the first skin graft operation: early = operatedon within 14 days of injury; delayed = operated on more than two weeks after injury. Results: A totalof 84 patients were included in the study, 43 who had an early operation and 41 who had a delayedoperation. There were no differences between the groups regarding burn size, or whether the burnswere superficial or deep. The mean duration of healing time was seven days longer in the group withdelayed operation (p = 0.001). The area operated on was somewhat larger (not significantly so) in thegroup who had early operation. Nine children had two skin graft operations, eight in the early groupand one in the delayed group (p = 0.03). Conclusion: The patients who were operated on early hadthe advantage of a shorter healing time, but there was a higher rate of complementary operationsand a tendency towards a larger burn excision

Reconstruction of sternal defects after sternotomy with postoperative osteomyelitis, using a unilateral pectoralis major advancement muscle flap

BACKGROUND: The pectoralis major flap, which is usually harvested bilaterally, is considered a workhorse flap in the reconstruction of sternal defects. After a median sternotomy for open heart surgery, 1%-3% of patients develop deep infection and dehiscence of the sternal wound, some of which will eventually require reconstructive surgery. Our aim was to describe the clinical feasibility and associated complications of the unilateral pectoralis major advancement flap in the reconstruction of sternal defects. METHODS: A retrospective analysis of all adult patients who were operated on using a unilateral pectoralis major flap for reconstruction of the chest wall at the Linköping University Hospital during 2008-18 was made using data retrieved from medical records. RESULTS: Forty-three patients had reconstructions with unilateral pectoralis major flaps. Three flaps failed completely, and another 10 patients developed complications that required further operation. The factors that were independently associated with loss of the flaps and complications were: older age, male sex, the number of different antibiotics used, and a long duration of treatment with negative wound pressure. Fewer wound revisions before the reconstruction resulted in more complications. The factors that were independently associated with prolonged time to complete healing were emergency reoperation after the initial operation and complications after reconstruction. CONCLUSION: The unilateral pectoralis major advancement flap has proved to be a useful technique in the reconstruction of most sternal defects after sternal wound infection in older patients. There is, however, need for a follow-up study on a larger number of procedures to evaluate the long-term outcome compared with other methods of sternal reconstruction.Funding agencies: Linkoping University</p

Versatility of the Extensor Digitorum Brevis Muscle Flap in Lower Limb Reconstruction

Background:. Reconstruction of complex defects in the lower leg is a challenge. Although microvascular free tissue transfer is a popular technique, experience and available resources limit its use. Furthermore, free tissue transfer is not always required in the reconstruction of small lower leg defects, as many of them can be reconstructed with local alternatives such as an extensor digitorum brevis flap (EDB). Our aim was to describe our experience of the last 20 years with the EDB as a local muscle flap to cover small complex lower leg defects to establish its clinical feasibility and to document its associated complications. Methods:. All adult patients who were operated with EDB flap reconstruction of the lower limb during 1997–2017 at the Department of Hand and Plastic Surgery, Linköping University Hospital, were included in this retrospective study. Results:. Of 64 patients operated, only 7 had total flap failure, and the rate of complete success was 73% (47/64). Most of the skin defects were associated with fractures or complications thereof and were located in the ankle region, the dorsum of the foot, and the distal third of tibia or even the proximal tibia. Defects in the malleolar region and coexisting cardiovascular condition were factors associated with flap loss (either partial or total). Conclusion:. The pedicled EDB-flap has, in our hands, proved to be a versatile and safe reconstructive option in the reconstruction of small defects in the lower leg and foot. Long-time follow-up is, however, recommended