Tehran University Medical Journal

Background: Velopharyngeal insufficiency causes hypernasal vocal quality and can also result in audible nasal air emission and difficulty in producing pressure consonants. The resulting speech is often socially unacceptable and can be difficult to understand. Platelet-rich plasma is an autologous derivative of whole blood. Today, the importance of clinical use of Platelet-rich plasma in the plastic surgery is considered. This study was designed to evaluate the effectiveness of combined Platelet-rich plasma and fat injection in the treatment of velopharyngeal insufficiency.

Methods: In this prospective clinicaltrial study, of 15 patients including 9 males and 6 females and aged 15-20 years with mild/ moderate velopharyngeal insufficiency who were injected with 5 mL of combined Platelet-rich plasma (1 mL) and fat (4 mL) in the front volume in the posterior pharyngeal wall in the pre-vertebral fascia under sedation. Speech samples were recorded by nasoendoscopy before the injection, and at 6 weeks and 6 months after the injection. Assessment of pathologic speech was done by speech therapist.

Results: Velar displacement showed significantly increased at 6 weeks after the injection (P=0.049). Velopharyngeal gap disappeared in 60% of patients at 6 weeks after the injection (P=0.019). Lateral pharyngeal wall movement showed significantly increased in 73.3% of the patients at 6 months after the injection (P=0.04). After the treatment, aerodynamic assessment showed significantly decreased in nasal air escape during phonation and repeat the words (P<0.05). Assessment speech therapist showed significantly improve quality of phonation in these patients (P<0.05).

Background: Peripheral nerve injury is one of the most challenging of modern surgical problem. Recent advances in understanding the physiological and molecular pathways demonstrated the important role of growth factors in peripheral nerve regeneration. Platelet-rich plasma (PRP) is a biological product that has many growth factors. The aim of this study was to investigate the effect of PRP in the regeneration of sciatic nerve crush in the rat model.

Methods: In this experimental study that established in the animal lab of the Hazrat Fatemeh Hospital in Tehran from September to October 2013, Twenty-four healthy male Sprague-Dawley rats (200-250 g) were randomly divided into two groups. In all rats the sciatic nerve was cut and then carefully repaired by the tension free method under a light microscope. In group 1, after the repair, 0.05 µL of PRP was injected below the epineurium to the proximal and distal parts of the repaired area. In group 2 the same amount of normal saline was injected to the proximal and distal of the repaired area. After six weeks footprint analysis, neurophysiologic and histopathology evaluations were performed.

Results: Significant differences existed between the two groups footprint analysis (P= 0.001). Also the nerve conduction latency test was significantly shorter in PRP group. (1.0233 ms in PRP group and 1.7375 ms in control) (P< 0.001). The average amplitude in the first group and the second group was 7.6250 mv (control) 6.3667 mv that does not show a statistically significant difference (P= 0.093). Significant differences between the two groups in the number of axons of the proximal portion of the study was not seen (P= 0.29). The parameters included number of axons of the proximal and the distal part of axons, the diameter of the distal and proximal axons in the two groups were compared. In the two groups there was statistically significant difference between the above parameters. (P= 0.298).

Conclusion: It seems that PRP may have an important role in peripheral nerve regeneration and functional recovery after nerve laceration and repair. Further clinical evaluation recommended.

Background: Graft survival has been considered the major problem in reconstructive surgery. Clinical studies have helped us to understand the role of PRP in increasing skin survival. Our goal in this study was to examine the treatment effects of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) on autologous full thickness skin graft survival in male rats.

Methods: This experimental study was performed on 36 rats of Sprague-Dawley race with weighing approximately 250 to 300 gr on May 2015 in animal laboratory of Hazrat Fatima Hospital. After anesthesia, rats were divided into 3 groups. We injected platelet-rich plasma (PRP) in the first group, platelet-rich fibrin (PRF) in the second and saline in the third group after removing the skin. Microscopic analysis was performed with camera (Canon powershot SX200, Tokyo, Japan) on days 7, 14, 21 and 28 after surgery. We used image analysis system (ImageJ, ver. 1.45) to examine necrosis and survival rate. Samples were studied with H&E staining on day 28 microscopically for histological analysis of vascular density and angiogenesis.

Results: Our findings showed the area of necrosis in animals injected with PRP on days 7 and 14, was meaningfully less than control group (P= 0.0001). There was no meaningful difference between control and PRP groups (P> 0.05). The area of necrosis in animals injected with PRF did not have any significant difference with control group from beginning to 21st day (P< 0.0001). there was no meaningful difference in vascular density between control and PRP group, whereas in animals injected with PRF the vascular density was significantly less than control group (P= 0.002).

Conclusion: According to our results in this study, we can conclude that using autologous PRP can enhance the process of healing soft tissue injury and be affective at increasing graft survival. This method is suggested to be conducted for patients highly at risk of graft loss and also for those who are in need of early treatments.

Background: Major platelet adhesive receptors that contribute significantly to thrombus formation include platelet receptor glycoprotein Ibα (GPIbα) of the GPIb-IX-V complex and platelet glycoprotein VI (GPVI). GPIbα plays a crucial role in platelet tethering to sub-endothelial matrix, which initiates thrombus formation at arterial shear rates, whereas GPVI is critically involved in platelets firm adhesion to the site of injury regardless of shear condition. During storage, platelets experience some changes that deleteriously affect the expression levels of platelet receptors, which in turn can alter platelet functional behaviors. Considering the important roles of GPIbα and GPVI in platelet adhesion, it seems that any dramatic changes in the expression levels of these receptors can influence adhesive function of transfused platelets. Thereby examining GPIbα and GPVI expression during the storage of platelet concentrates may provide some useful information about the functional quality of these products after transfusion.

Methods: In our experimental study, 5 PRP-platelet concentrates were randomly obtained from Iranian Blood Transfusion Organization (IBTO). All the platelet products met the standard quality assessment based on AABB (American Association of Blood Banks) guidelines. Washed platelets were subjected to flowcytometry analysis for the evaluation of GPIbα and GPVI receptor expression in day 1, 3 and 5 after storage. Data were presented as mean fluorescence intensity (MFI) and analyzed by Kruskal-Wallis test with Dunn’s multiple comparison test.

Results: The GPIbα expression on first day (MFI=86±5.9) was reduced three days after storage (MFI= 69±6.9). The expression levels continued to reduce until day 5 in which GPIbα expression was markedly decreased to (MFI= 61±7.7) (P= 0.0094). GPVI expression on the days 1, 3 and 5 after storage were 20.6±3.3, 24±2.5 and 14±4.9, respectively. The results showed a significant decrease of expression on day 5, compared to that in day 3 after storage (P= 0.0213).

Conclusion: Our study showed significant decreases in the expression of platelet receptors GPIbα and GPVI after 5 days storage, suggesting a major defect in adhesive function of platelets during this term.

Background: Platelet adhesion typically occurs by the critical role of GPIb-V-IX in capturing free-flowing platelets to the injured vessel wall where its rapid binding kinetics enables platelet tethering even under conditions of high shear through the interaction of the major ligand-binding subunit of GPIb-V-IX, GPIbα with subendothelial-bound vWF. During storage, platelet undesired activation may lead to platelet storage lesion (PSL) which changes the expression levels of platelet functional receptors including GPIbα. This study investigates the levels of expression and ectodomain shedding of platelet adhesive receptor GPIbα during the storage of platelet rich plasma (PRP) concentrates (PRP- PCs).

Methods: Five PRP-platelet concentrates were obtained from Iranian Blood Transfusion Organization (IBTO). The GPIbα expressions of platelets were analyzed on day 1, 3 and 5 after storage using flowcytometry. To examine the ectodomain shedding of this receptor the microparticle free supernatants obtained from stored platelets were subjected to western blot analysis. For control study, blood specimens was drawn from healthy consenting individuals and resting platelets were isolated while resuspended in Tyrode buffer.

Results: Our results indicated a continuous decrease of GPIbα expression during storage where the expression from fist day (Mean fluorescence intensity=86±5.9) was significantly reduced compared to that of fifth day (mean fluorescence intensity=61±7.7) after storage (P=0.0094). Conversely, shed GPIbα (Glycocalicin) demonstrated continuous elevation during five-day storage (P=0.0098). According to the results the shedding levels for the first day were increased from 0.31± 0.3 to 1.5± 0.4 by the day 5 after storage.  

Conclusion: Our study has demonstrated significant loss of platelet GPIbα during storage mostly due to receptor ectodomain shedding that leads to significant increase of soluble GPIbα in stored platelets. Considering the high levels of shed GPIbα in long stored platelets whether the transfusion of such products might be associated with defective adhesive function of platelets or possible proinflammatory effects could be of interests for future investigation.