**4. Plasma growth factors (PRP) in cerebral palsy**

**3. Definition of plasma growth factors**

**Table 1.** Summary of the proteins in the platelet alpha granules.

**Content Feature**

126 Cerebral Palsy - Clinical and Therapeutic Aspects

**Clotting factors V and VIII** Thrombin production

**plasminogen activator inhibitor** Inhibition of fibrinolysis

\*Rantes: regulated on activation normal T cell expressed and secreted.

**P-selectin** Leukocyte-platelet interaction

**Von-Willebrand factor** Platelet adhesion to subendothelial collagen

**Immunoglobulins G** Ig-A, Ig-E, Ig-M and Ig-G

count exceeds 1000,000/mm<sup>3</sup>

mononuclear cells [4–6] (**Table 2**).

Platelets (150,000–350,000/mm<sup>3</sup>

Leucocytes (3200–9000/mm<sup>3</sup>

**Peripheral blood PRP**

Granulocytes 60% (3330/mm<sup>3</sup>

Mononuclears 35% (1960/mm<sup>3</sup>

**Table 2.** Levels of growth factors and cell count in peripheral blood and PRP.

of patient's serum with a count higher than 20,000/ mm<sup>3</sup>

Growth factors are obtained in an autologous way from the whole blood of the same patient with the aim of reducing the possibility of producing hypersensitivity effects or transmission of infectious diseases during their application. It is called leukocyte-rich plasma or (PRL) to the suspension of the mononuclear fraction or buffy coat in a quantity

Immunological

would be that platelet concentrate suspension in a small amount of patient serum whose

is estimated between 6.5 and 6.7 at a temperature of 22°C. Recent studies, such as the one led by the group of Dr. Alcaraz et al., have observed the predominance of PDGF and IGF-like plasma growth factors in platelet-rich suspensions, while other growth factors such as VEGF or TGF would predominate in those final concentrates rich in leukocyte-

) 265,000/mm<sup>3</sup> 1,250,000/mm<sup>3</sup>

) 5600/mm<sup>3</sup> 20,000/mm<sup>3</sup>

PDGF-AB (10–50 pg/ml) 45 pg/ml 360 pg/ml TGF-B1 (10–70 pg/ml) 35 pg/ml 320 pg/ml VEGF (15–85 pg/ml) 55 pg/ml 560 pg/ml IGF-1 (0.5–19.5 pg/ml) 13 pg/ml 175 pg/ml

CD 34+ 0.5/mm<sup>3</sup> 175/mm<sup>3</sup>

of platelets. The optimum pH to obtain both cellular fractions

) 24% (480/mm<sup>3</sup>

) 70% (14,000/mm<sup>3</sup>

)

)

; while platelet-rich plasma (PRP)

PRP produces a release of cellular signaling molecules only or in combination that have been shown to produce both neuroprotective and anti apoptotic effect on the neuron and adult neural stem cells repairing neural tissue. Plasma growth factors constitute support that facilitates the survival and neuronal differentiation [2, 3, 7].

It has been shown that application of autologous plasma growth factors had a neuroprotective and antifibrotic effect, improving nerve regeneration probably induced by the activation of the PI3K/Akt anti apoptotic signaling pathway [2].

We do not yet have enough studies to evaluate effect of angiogenesis in the nerve repair. Administration of autologous PRP rich in VEGF and IGF-1 accelerates the regeneration of the neuromuscular junction owing to the increase of angiogenesis. Intramuscular injections of PRP would increase the angiogenesis and produces reperfusion after the induction of a severe skeletal muscle ischemia [2, 3, 7].

The main function of PRP has been showed in a rat brain sample, where application of plasma growth factors induced both the increase in the number and the growth of axons. The PRP has been used in a model of acute cerebral nerve injury in rabbits, as a culture medium to neurological stem cells reporting beneficial effects on axonal count, myelination and electrophysiological functionality. PRP could increase both the thickness of the myelin and amount of axons, producing an increase in functional activity at the date of latency associated with improvement in the thickness of the myelin. PPR could contribute significantly to the two key events for a proper axonal regeneration: angiogenesis and the establishment of an optimal microenvironment for the differentiation, immunomodulation and cell division [1–3, 5, 6].

It has been objectified an anti-inflammatory activity of PRP, aiming that b-amyloid expresses cytokines inhibited when astrocytes are cultivated with autologous growth factors, that could be explained by suppression of NFkB in astrocytes with the activation of the Cyclooxygenase and the expression of tumor necrosis factor in the brain. Several studies have reported that plasma growth factors like IGF-1, PDGF and TGF-B, could inhibit the NFkB on the tenocytes, synovial cells, fibroblasts, chondrocytes and change the macrophages from phenotype M1 to M2 [2, 6, 7].

The growth factors would produce neurogenesis phenomena through 3 ways: first inhibiting the inflammatory process that would difficult the anatomical and physiological neuronal recovery; secondly improving the migration and proliferation of stem neuronal cells at the site of the lesion and finally stimulating its differentiation toward mature neuronal mass reestablishing the normal functional circuit of the same.

The lesion of a neuron actives macrophages and mononuclear cells like Monocytes that phagocyte the myelin residues, stimulating by autocrine way the nerve growth factor (NGF), that facilitates the recruitment of Schwann cells to the area of the lesion, their differentiation and proliferation join to the vasculo-endothelial growth factor producing remyelination and final reconnection of the affected axon.

#### **5. Discussion**

The evolution of regenerative medicine in various clinical areas revolutionizes the field of tissue repair, providing an instrument for treatment which is economical, easy to use, no side effects, and less invasive [1, 3]. However, scientific and social requirements make it necessary to design appropriate clinical trials to establish treatment protocols for each particular medical application [1, 2]. Today, medical areas with stronger scientific evidence to use plasma growth factors are dentistry (to repair the dental alveolar bed) and traumatology (arthropathy, tendinopathy, ligament injuries, and meniscopathy), with proper design randomized clinical trials in phase I-II [1, 4]. But the empirical use in many diseases and medical specialties sometimes exceeds the capacity to produce sufficient scientific evidence power for use. An important fact to comment, as previously demonstrated by other authors is the great capacity of these proteins to spread through the tissues and the short half-life objectified once achieved therapeutic plasma levels that do not usually exceed 48–72 h [8, 9], which shows that the actuation mechanism is complex, it is believed that activating pathways or biochemical cascades through numerous chemokines or cytokines that involve in the inflammatory processes both specific tissue, such as migration, proliferation and differentiation of precursors cell maturation in different states and angiogenesis phenomena would produce increased tissue oxygenation with the consequent increase in cell survival and protection thereof. Some more promising medical fields for the use of this biotechnology are neurology, neuroendocrinology and neurorehabilitation. A few months ago was published the first clinical case of cognitive improvement supported by cerebral PET in a 5 years old child with severe cerebral palsy who was applied by intravenous infusion a plasma concentrate growth factors-enriched with buffy-coat mononuclear fraction. Several authors hypothesized neuroregenerative phenomena, antiapoptotic, immunomodulatory and neurotrophic effects that would produce these autologous plasma growth factors on neuronal tissue, making this a feasible therapy from a medical point of view, to be applied in neurological diseases with neurodegenerative profile or hypoxic-anoxic, such as Alzheimer's disease, brain-stroke, spinal cord injury, and cerebral palsy [5, 6]. Spontaneous remission of the signs and symptoms of cerebral palsy is rare due to the large number of neuronal glial mass and degenerate secondary to the effects of hypoxia in the evolution of the disease [9]. Effects of neurostimulation, neurodegeneration and neuroprotection have been observed in these patients treated with synthetic growth hormone (HGF), which causes functional improvement, especially in the cognitive domain (e.g., memory, language, ability to perform complex tasks, and acquisition of new skills). In these patients, the neuronal degenerative effect has been accompanied by a qualitative and quantitative marked decrease in plasma growth factors such as HGF-IGF-1-VEGD, PDGF, and TGF-B [7–9], regulated by the hypothalamic axis pituitary, which produce a neuroprotective effect, due to neurotropic and chemotaxis phenomena, cell differentiation, and neuroplasticity in neuronal tissue. Furthermore, these substances have the ability to stimulate the so-called gray areas corresponding to those neural tissues found in hibernation as a result of lesional hypoxic or anoxic effect. However, treatment with synthetic growth hormone is costly, not only from the economic standpoint but also from the clinical point of view.

**Author details**

**References**

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Jesús Alcaraz Rubio\* and Juana María Sánchez López

Unión Murciana de Hospitales, Murcia, Spain

\*Address all correspondence to: jesusalcaraz@telefonica.net

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