Acceleration of wound healing by topical drug delivery via liposomes

BACKGROUND

Despite intensive research, impaired wound healing remains a considerable complication. Therefore, topically applied liposome-encapsulated buflomedil hydrochloride was investigated for its ability to improve wound repair in normal (n=16) and ischemic (n=16) skin tissue.

METHODS

Experiments were performed using the wound healing model of the ear of hairless mice. Standardized skin wounds (4.25 mm(2)) were created by circular excision of the epidermal layer and the subcutaneous tissue. Liposomes were applied daily until complete neovascularization of the wound occurred. Tissue regeneration by complete epithelialization and neovascularization of the wound area, microcirculatory parameters, and leukocyte-endothelium interaction were investigated by means of intravital microscopy. Microvascular perfusion was assessed by laser-Doppler flowmetry.

RESULTS

Topical application of buflomedil liposomes led to a significantly (P<0.05) accelerated wound closure in both normal (9.6+/-0.7 days) and ischemic (13.4+/-0.1 days) skin tissue compared with animals that were treated with unloaded liposomes (controls; 13.1+/-0.8 days; 15.3+/-0.6 days). Complete neovascularization of the wound was also enhanced (P<0.05) in buflomedil-treated animals (normal tissue 18.8+/-0.4 days; ischemic tissue 19.6+/-0.7 days) compared with controls (20.6+/-0.6 days; 22. 6+/-1.2 days).

CONCLUSION

These data suggest that buflomedil-loaded liposomes might be of beneficial use for clinical wound care.

Reduction of skin flap necrosis by transdermal application of buflomedil bound to liposomes

The influence of the vasoactive drug buflomedil hydrochloride bound to liposomes (2 mg/ml) was investigated in an arterial pattern skin flap model using the ear of hairless mice. For flap creation, the ear is cut at four-fifths of its base, which leaves the anterior artery as the only feeding vessel of the flap. Liposomes were locally applied daily for 30 minutes up to 5 days after flap creation. Microvascular perfusion in the proximal, central, and distal parts of the flap was measured by laser Doppler flowmetry. The border between perfused and nonperfused tissue was visualized by intravital fluorescence microscopy using fluorescein isothiocyanate (FITC)-labeled dextran (Mr 150,000) for contrast enhancement of microvessels. The area of nonperfused tissue was assessed by digital planimetry. Five days after flap creation the nonperfused area amounted to 23.8 +/- 3.1 percent of total flap surface in treated ears compared with 46.1 +/- 5.6 percent in untreated ears (p < 0.05) of the contralateral side. Additional preoperative treatment for 5 days did not further reduce the area of nonperfused tissue (treated ears, 23.0 +/- 1.3 percent; control ears, 44.6 +/- 5.1 percent). Microvascular perfusion was higher in the postoperatively treated ears in all parts of the flap from day 1 after flap creation until termination of the experiment. Five days after flap creation, perfusion as measured by laser Doppler flowmetry was reduced to 46.0 +/- 10.8 percent in the distal part in control ears compared with 91.9 +/- 8.3 percent (p < 0.05) in treated animals. Additional preoperative treatment for 5 days did not result in further improvement. It is concluded that local application of the vasoactive drug buflomedil docked to liposomes could be of therapeutic use in the treatment of ischemic tissue, including skin flaps.

[Observations on organic components of thermal mud: morphohistochemical and biochemical studies on lipid components of mud of the Terme dei Papi (Laghetto del Bagnaccio, Viterbo). Chemical bases of the interpretation of biological and therapeutic actions of thermal mud]

In previous findings the lipidic fractions extracted acc. to Folch from the mature muds of the majority of the Italian thermal springs hot baths was studied, with the aim to identify the organic substrates of their therapeutical activity. The organic components of the "mature" peloids are produced by the metabolism of the microphytozooplankton growing spontaneously in the clay-substrate, in contact with the hot water. The Popes thermal springs (Bagnaccio's Lake) are characterised by an unique environmental situation, because the muds are naturally matured in the hot thermal water, but not in artificial baths. The morphohistochemical aspects of thermal algae growing in the Bagnaccio's lake have been studied by means of Computerised Optic Probe Video-Microscopy, using a not contact zoom objective 70-400x. Peloid types, both the "white" and the "black" contains yellow pigments, fragments of hyphae, monocellular algae, Diatomeae, Cyanophyceae and few other species. The biochemical aspects of the muds extracts are characterised by the presence of Phospholipids (PC, PE, PS, SP), a series of Hydrocarbons ranging from C30 to C38, Phytosterols (beta-sitosterol, Campesterol, Stigmasterol and traces of Cholesterol), Free Fatty Acids (Palmitic, Palmitoleic, Myristic, Stearic, Oleic and Linoleic, heptadecenoic and heptadecanoic) and Terpenes (beta-amirrhyne, 24-methylene-cyclo-arthanole). In our opinion, the therapeutic effects of the mature muds are related to its organic components, with special regards to Phospholipids, Phytosterols and Terpenes. The richness of these components in the Popes Thermal springs seems to be great interest in the dermatological and cosmetic applications, other then the traditional use.

Evidence and results obtained with a new trans-epidermal barrier (T.E.B.) drug in the medical treatment of vascular impotence

After having reviewed the methods and significance of a new topical administration route for vasoactive drugs, the "Trans-Epidermal Barrier" (T.E.B.), based on the physiological capacity of phosphoric ester molecules (Phosphatidylcholine) to penetrate actively through the epidermal barrier, this paper reports the results obtained in the medical treatment of (micro) vasculogenic impotence with a preparation in the form of a 5% Lipogel, containing, as active principle, a Troxerutine/Phosphatidylcholine Complex. A total of 154 patients were subjected to "short term" treatment in order to quantitatively assess (computer assisted laser-Doppler: LDF) the response of the small arteries and arterioles in the dorsal penile region to pharmacological stimulation (microvasculokinesis test). This test enables separation of the patients into two groups: "responders" and "non-responders", according to which it is possible to instrumentally assess the severity of the anatomo-functional alteration of the small arteries and arterioles in penile microangiopathies originating from diabetes, arteriolosclerosis, hypertension and stasis. Microvascular damage was assessed objectively with the Optic Probe Video-Capillaroscopy, taking into consideration the number of microaneurysms and extension of the subischemic or ischemic areas. 75 "responder" patients undertook long term treatment for a minimum period of three months with the same preparation used for the microvasculokinesis test, at the dose of 2-3 topical administrations per day. The clinical parameters for the evaluation of efficacy were): a) number of spontaneous daily erections; b) duration of the erections; and c) penile rigidity; in addition to subjective elements such as recovery of satisfactory sexual activity consistent with the anatomo-functional damage. The response to the treatment was positive in 54 patients (72% of the cases). The clinical improvement was confirmed by the instrumental LDF results, that show a statistically significant increase (P < 0.0001) in the sphygmicity ("pumping function": inotropic potency of the arterio-arteriolar systole) of the small penile arteries, i.e.:92.63 +/- 26.1 at baseline to 177.6 +/- 74.5 after treatment. Follow-up continued in 15 patients for 6 months and in 11 patients for 12 months. Maintenance of the results was achieved by continuing treatment involving gradual reduction of the number of applications. The new route of application proposed by the authors and the investigation methods adopted for objective instrumental assessment of penile microcirculatory damage in (micro) vasculogenic impotence provides new perspectives from the diagnostic as well as the prognostic and therapeutical viewpoints.

[Biological activity of a carrier molecule-iron complex: probable mechanisms of intestinal absorption]

The physical-chemical properties of a new Iron-Protein complex, the so called "Iron Yeast" biotecnologically produced by Saccharomyces cerevisiae cell cultures, are reported. Using atomic absorption methods the amount of free iron in the complex has been evaluated, ascertaining that 99% of Iron is structurally bound to the protein matrix. Iron Yeast is a further, original contribution to the treatment of iron-deficiency anemias, showing a satisfactory clinical activity and a lower amount of undesired side effects in comparison with other Iron-Protein complexes.

Microangiopathy of ethylic polyneuropathy

The authors have studied, by biopsy of the tip of the big toe, the histologic changes in microvessels of patients affected by ethylic polyneuropathy. Patients affected by diabetes, hypertension, peripheral arterial or venous diseases, or dermatologic diseases or vasculitides were excluded. The mean of daily drinks was 310 +/- 105 g of alcohol, chiefly wine. Important pathologic modifications were noted; complete narrowing of the arteriovenous anastomosis, regressive changes of the Vater-Pacini corpuscles, and dilatation of the small veins and the capillaries. The findings were compared with those of a patient affected by ulcerans and mutilans acropathy of Bureau and Barriere, a typical disease of alcoholics. The same characteristics appeared: profound changes of the structure of the smallest vessels, with sclerosis, extended to the interstitium. In a previous study of the authors, 3 other patients affected by Bureau-Barriere disease showed the same pattern. These alterations can be explained as the effect of alcohol on the microvessels.

[Venous stasis and panniculopathy: a semiologic study]

The relevant role played by the microcirculation on several pathologies and on the genetic evolution of rarely known diseases as the panniculopathy with venous stasis have been explained. It represent a support on the concept for new research of microcirculation's injuries as a primary factor on macrophlebopathies.

[Microvascular anatomy of the skin and its appendages]

The microcirculatory bed of the skin has traditionally been divided into small arteries, precapillary arterioles, capillaries and venules. Also the most recent classification emphasize that the blood supply of the human dermis is a microcirculatory bed. Therefore, considering for example the skin of the lower limbs, there are too much anatomic and topographic peculiarities of the skin and subcutaneous tissue, so that a generalization of the microcirculatory patterns appears to be illusory and misleading. In fact, the foots plant is a "special microcirculatory region", and so the finger tips and the nail beds. Rich on arterio-venous anastomoses, on endoarterious blocking devices regulating the capillary blood flow, this "microcirculatory region" is characterized by haemodynamic patterns which are not comparables with those of other regions where AVA or other "special vessels" are absent. The microangiotectonic, i.e. the distribution in the tridimensional space of the dermis, adipose tissue and muscle of the smallest blood vessels show relevant differences in the foots, legs, knees or thighs. Normally, it is admitted that the majority of the papillary dermal vessels are postcapillary venules, but the ultrastructure of the arterioles and venules in the mid and lower dermis differs from the ultrastructure of comparable vessels of the deeper layers or of the subcutaneous fat. For these reason and on the basis of bioptic specimens of the skin, adipose tissue and muscles of the whole lower limbs, the subdivision in "microcirculatory regions" is proposed. The criteria are the presence or absence of AVA, the structure and localization of the endoarterious blocking devices, the structure of valve-containing venules and the microvessels-tissue relationship. Computerized Laser-Doppler Flowmetry and infra red Photo-Pulse Plethysmography, computerized Telethermography with physical stimulations, High Performance Contact Thermography and continuous registration of the skin temperature associated with pharmacological vasoactive stimulation, are helpful to identify and characterize functionally the "microcirculatory regions" of the lower limbs.

A new capillaroscopic assessment of microvascular damage vs Maricq classification in patients with isolated Raynaud phenomenon

A new classification for microvascular lesions assessment by means of capillaroscopy is proposed in this research. The new method, offering a numerical score for microvascular lesions, was used in patients affected by isolated Raynaud Phenomenon (RP). RP can often be associated with scleroderma and, therefore, the new classification has been compared to the Maricq one for what concerns this connective tissue disorder. The numerical method is as sensitive as that by Maricq, but, as easily expected, its specificity is quite low. It appeared to be satisfactory also the positive predictive value of the new capillaroscopy classification combination with the clinical examination and with the immunologic biohumoral investigation. It is particularly easy to apply this method, as it presents to the examinator a restricted range of answers, for the capillaroscopic picture description, but it needs further studies in different microcirculation damages to be proved definitely valuable.

[Microcirculatory changes in Bureau-Barrière disease and alcoholic polyneuropathy. Preliminary note: correlations and pathogenic hypotheses]

Nosologically, in ulcerative-mutilating acropathies (U.M.A.), it is customary to differentiate the usual forms of the disease (Thevenard's disease) which develop primarily and the secondary forms (U.M.A. or, better, pseudo-U.M.A.), in which the syndrome is secondary to a known pathologic process and which represent a symptom and not a disease. The link between these two nosological entities is the pseudo-syringomyeli U.M.A. of the lower extremities, or Bureau-Barrier's disease. This disease is exclusively seen in alcoholics and is similar to the neurological alterations observed in alcoholic polyneuropathies. Some authors consider this form as an ulcerative-mutilating acropathy (symptomatic U.M.A.). The objective of our research is to demonstrate the similarity between the microcirculation alterations in patients with Bureau-Barriere's disease and patients with alcoholic polyneuropathy without trophic lesions. For this purpose, we have biopsied the pulp of the great toe, according to the method described by Curri-Schendorf in three patients with Bureau-Barriere's disease, 46, 50 and 65 year-old respectively, and three patients with alcoholic polyneuropathy, 34, 54 and 63 years-old respectively. All these patients presented a normal macrocirculation, without any diabetes, nor disease prone to alter the microcirculation. The results obtained, in a limited series however, permit to state that it is possible to unify alcoholic polyneuropathy and Bureau-Barriere's disease in a single clinical and nosological entity, and to say that the latter only represents an evolution of the former. Besides, we have notices that microcirculation alterations, although non-specific, are extensive and occur early, permitting to suspect a pathogenic process related to a true alcoholic histo-angeitis which, for us, represent the pathogenic basis of Bureau-Barriere's disease.

[Microvalves in microvenules]

A long-lasting histological study on muscle and cutaneous-subcutaneous biopsies allowed certain observations of microvalves in venules with a diameter ranging from 80 to 200 micron. Venular leaflets originate from the vein as extroflection of the intima, made by a single layer of endothelial cells. In the patient affected by severe chronic venous insufficiency the valvular leaflets appear thickened while the wall of the venule presents sclero-hyalinotic alterations. The presence of microvalves in venules suggests a role of their incontinence in the venous insufficiency. Considering that the venular leaflets are made just by endothelial cells, a primary pathogenetic role has to be achieved to the endotheliopathy in the genesis of venous insufficiency.

Multiple Pacinian neurofibroma and relationship with the finger-tip arterio-venous anastomoses

Multiple Pacinian neurofibromas involving the three phalanges of the ring finger of the left hand in a 60-year-old woman are described. The abnormal proliferation of Vater-Pacini corpuscles in various stages of differentiation was associated with marked changes of the glomus type of arterio-venous anastomoses of the finger-tip. The close relationship between the new proliferated Vater-Pacini corpuscles, their altered baresthetic function and the pathological shunting of blood account for the painful Raynaud-like symptoms. The name 'Pacinian neurofibromatosis' is proposed.

[Cellulitis, a conjunctive microvascular disease]

While the term cellulitis is incorrect, it is commonly used and deserves a nosological classification. "Cellulitis is a dermohypodermosis and an oedemato-sclerous panniculopathy- It is indeed a true histangiography in which the fibroblastic reaction predominates over capillaro-veinular changes. Adipocytes of exaggerated size interpenetrate into micro- and later into macronodules marked off by more or less structured conjunctive fibrilla, thereby making treatment difficult.

[Anthocyanosides and the walls of the microvessels: further aspects of the mechanism of action of their protective effect in syndromes due to abnormal capillary fragility]

On the basis of previous biochemical observations, which have demonstrated the formation of complexes between anthocyanosides and some phospholipids, the AA. investigate the modifications induced by local and general administration of anthocyanosides 1) on the foreign body granuloma and 2) on the composition of the protein fractions in the exudate from the capillaries of the granulation tissue, growing on post-thromboflebitic or varicose leg ulcerations. The biochemical and histochemical data may show that the anthocyanosides protect the altered capillary walls with a double mechanism: a) increasing the endothelium barrier-effect through a stabilisation of the membrane phospholipids and b) increasing the biosynthetic processes of the acid mucopolysaccharides of the connective ground substance, by restoring the altered mucopolysaccharidic pericapillary sheat. This last effect may explain the marked increase of new-formed capillaries and collagen fibrils induced by the anthocyanosides.

The fine structure of human digital arterio-venous anastomoses (Hoyer-Grosser's organs)

Hoyer-Grosser's organs were studied in human digital biopsies. The fine structure of both the supplying arteries and collecting veins was found to be inconspicuous. Endothelial cells in the AV canals form a continuous layer. They are characterized by their rich content of specific organelles (Weibel-Palade bodies), especially in the venous segments. The epitheloid zone is composed of a variety of ramified smooth muscle cells (RSM). These appear either dense, when well provided with bundles of myofilaments, or clear, when including only a few myofilaments. The nuclei of dense RSM show condensed chromatin, while those of clear RSM are larger with loose chromatin texture. In addition, all transitional forms occur. Cell organelles are rarely seen within all types of RSM. The cytoplasmic processes reach other as well as endothelial cells. The preservation of our material did not allow observation of specialized membrane contacts in these zones. All RSM are invested with a regular basal lamina and well provided with surface vesicles. Profiles of free basal lamina material and faint collagen (argyrophil) fibers are seen in the wide intercellular spaces. RSM poor in myofilaments are interpreted to represent "epitheloid cells" of light microscopy. Their number constantly decreases from the arterial segment of the AV canal to the venous segment. Here the cytoplasmic processes of RSM become less pronounced and the wall of the anastomotic segment continuously changes to that of the collecting vein. Dense RSM rich in myofilaments are compared with pacemaker cells found inthe ureter. Both internal and external elastic membranes are absent in AV canals. A dense network of unmyelinated nerve fibers is found in the adventitial layer of the AV canal, especially in its arterial segment. The axons branch out from small dermal nerves which also contain two or three myelinated axons. The myelin sheaths terminate where the axons reach the adventitia of the AV canals. Axon varicosities filled with mitochondria are thought to be terminals of myelinated axons and are interpreted as receptory. Axon varicosities with synaptic-type vesicles are assumed to be terminals of sympathetic and para sympathetic fibers. All axon profiles are confined to the adventitial layer of the anastomotic segment.

In vitro and in vivo observations on the erythrocyte uptake of 17-monochloroacetylajmaline

The in vitro and in vivo observations on the uptake rate of 17-monochloroacetylajmaline by human erythrocytes showed that about 30-35% of the drug is bound to red blood cells. These findings suggest a peculiar affinity of the drug for the erythrocytes, may be for the membrane or stromal phospholipids.

Plasma and red blood cell phospholipids in chronic liver diseases

The total phospholipid content and the individual phospholipids, phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine and phosphatidylserine, and sphingomyelin were determined in the plasma and red blood cells of 58 patients with chronic liver disease and 12 control subjects by quantitative extraction and thin-layer chromatography. The total phospholipids were significantly reduced in both the plasma and red blood cells of the patients with liver disease. For the individual phospholipids, plasma sphingomyelin was significantly decreased, in the red blood cells there was an increase in lysophosphatidylcholine and a decrease in phosphatidylethanolamine and phosphatidylserine compared to the control subjects. It is suggested that in chronic liver disease the red blood cell lipid disturbances follow more closely those of the hepatocyte than those in plasma.

[Total and fractionized plasma phospholipids in chronic liver diseases]

The literature data relating to the importance of the liver in fat metabolism, and the behaviour of plasma and red cell phospholipids, cholesterol, triglycerides, fatty acids and lipoproteins in acute and chronic liver disease is reviewed. The results of an investigation of the diagnostic and prognostic significance of total and single plasma phospholipid levels in a series of 70 cases (5 chronic aggressive hepatitis, 12 compensated cirrhosis, 41 uncompensated cirrhosis, and 12 controls) are presented. Quantitative assessment by means of thin-layer chromatography showed four features of marked prognostic interest: a) a significant decrease in total phospholipids; b) increased phosphatidyl choline; c) increased phosphatidyl ethanolamine; d) decreased sphingomyelin. In discussing the results, stress is laid on the fact that this method offers a sufficient close evaluation of the clinical picture with respect to both the evolution of cirrogenic liver diseases and the effectiveness of their treatment. It also enables an assessment to be made of liver cell mitochondria function.