Impact of Prevascularization on Immunological Environment and Early Engraftment in Subcutaneous Islet Transplantation

BACKGROUND

The utilization of islet-like cells derived from pluripotent stem cells may resolve the scarcity of islet transplantation donors. The subcutaneous space is a promising transplantation site because of its capacity for graft observation and removal, thereby ensuring safety. To guarantee subcutaneous islet transplantation, physicians should ensure ample blood supply. Numerous methodologies, including prevascularization, have been investigated to augment blood flow, but the optimal approach remains undetermined.

METHODS

From C57BL/6 mice, 500 syngeneic islets were transplanted into the prevascularized subcutaneous site of recipient mice by implanting agarose rods with basic fibroblast growth factor at 1 and 2 wk. Before transplantation, the blood glucose levels, cell infiltration, and cytokine levels at the transplant site were evaluated. Furthermore, we examined the impact of the extracellular matrix capsule on graft function and the inflammatory response.

RESULTS

Compared with the 1-wk group, the 2-wk group exhibited improved glycemic control, indicating that longer prevascularization enhanced transplant success. Flow cytometry analysis detected immune cells, such as neutrophils and macrophages, in the extracellular matrix capsules, whereas cytometric bead array analysis indicated the release of inflammatory and proinflammatory cytokines. Treatment with antitumor necrosis factor and anti-interleukin-6R antibodies in the 1-wk group improved graft survival, similar to the 2-wk group.

CONCLUSIONS

In early prevascularization before subcutaneous transplantation, neutrophil and macrophage accumulation prevented early engraftment owing to inflammatory cytokine production.

Molecular Retention Limitations for Prevascularized Subcutaneous Sites for Islet Transplantation

Beta cell replacement therapies utilizing the subcutaneous space have inherent advantages to other sites: the potential for increased accessibility, noninvasive monitoring, and graft extraction. Site prevascularization has been developed to enhance islet survivability in the subcutaneous zone while minimizing potential foreign body immune responses. Molecular communication between the host and prevascularized implant site remains ill-defined. Poly(ethylene oxide)s (PEOs) of various hydrated radii (i.e., ∼11-62 Å) were injected into prevascularized subcutaneous sites in C57BL/6 mice, and the clearance and organ biodistribution were characterized. Prevascularization formed a barrier that confined the molecules compared with the unmodified site. Molecular clearance from the prevascularized site was inversely proportional to the molecular weight. The upper limit in molecular size for entering the vasculature to be cleared was determined to be 35 kDa MW PEO. These findings provide insight into the impact of vascularization on molecular retention at the injection site and the effect of molecular size on the mobility of hydrophilic molecules from the prevascularized site to the host. This information is necessary for optimizing the transplantation site for increasing the beta cell graft survival.

Autologous Vascularization: A Method to Enhance the Antibacterial Adhesion Properties of ePTFE

BACKGROUND

Expanded polytetrafluoroethylene (ePTFE), an ideal bioimplant material, is commonly used in surgical repair to treat soft tissue defects and deformities. However, the main disadvantage of ePTFE is that its distinctive porous ultrastructure is prone to bacterial adhesion that gives rise to infection and chronic inflammation, resulting in functional failure. Herein, a potentially promising approach to ePTFE autologous vascularization (AV-ePTFE) in vivo was established and developed to enhance the material's antibacterial properties.

METHODS

Hematoxylin and eosin (H&E) staining and visual observation were performed to validate the intensity of the inflammatory response and related histological changes in surgical wounds after AV-ePTFE implantation. In addition, the antibacterial activities of AV-ePTFE were assessed by an in vitro bacterial adhesion assay and scanning electron microscope observation.

RESULTS

The optimal time point of AV-ePTFE was 12 weeks after implantation. AV-ePTFE relieved inflammation based on an inflammation grading evaluation and expedited wound healing. Furthermore, AV-ePTFE effectively reduced the number of bacterial adhesions, inhibited bacterial biofilm formation, and prevented the occurrence of infection.

CONCLUSIONS

We conclude that autologous vascularization is an effective method to improve the antibacterial adhesion properties and biocompatibility of ePTFE after implantation and that it may have a significant effect on clinical application of future porous biomaterials.

Circonscript Subcutaneous Arteriovenous Malformation of the Head

The aim of this study is to show the various possibilities to treat this rare malformation, accentuating the results of the early surgical treatment before complications.

MATERIAL

The authors present 8 cases of patients with subcutaneous arteriovenous malformations, 5 females and 3 males (age of 7, 13, 19, 23, 27, 52 and 58 years) treated in the period of 1999 until 2015 at the Clinic for Neurosurgery and the Clinic for Plastic, Aesthetic and Reconstructive Surgery in Skopje, Republic of Macedonia. This malformation has been observed by the parents in the childhood, around the age of 3 years in all cases. Local red circonscripted nodule, soft, with manually discharging tendency and varicose dilated veins have been observed in all cases, deaf on both sides in one case, while in the older case, a cavernous sinus thrombosis caused unilateral exophthalmia, hyaline indurated ophthalmic vein, vertigo, arrhythmia, heart failure and bradypsychia have been observed. The size of the malformation has been from 2.5 to 7 cm. The diagnostics was done using CT, CT-angiography and digital angiography including external carotid angiography. Endocranial arterials peduncle was present in all cases.

RESULTS

Six cases underwent surgery, while two cases were treated with several treatments of endovascular embolization. The follow up has been ranged from 2 to 15 years. All surgically treated patients improved without recurrence, the exophthalmia, bradypsychia and the heart problems regressed, while in patients treated with endovascular non-complete occlusion the AVM decreased, but still remained.

IN CONCLUSION

The Surgical treatment remains a first option if it is possible, and as earlier as possible, while embolization is a useful tool in cases where a complete excision is not possible.

SMAS Fusion Zones Determine the Subfascial and Subcutaneous Anatomy of the Human Face: Fascial Spaces, Fat Compartments, and Models of Facial Aging

BACKGROUND

Fusion zones between superficial fascia and deep fascia have been recognized by surgical anatomists since 1938. Anatomical dissection performed by the author suggested that additional superficial fascia fusion zones exist.

OBJECTIVES

A study was performed to evaluate and define fusion zones between the superficial and the deep fascia.

METHODS

Dissection of fresh and minimally preserved cadavers was performed using the accepted technique for defining anatomic spaces: dye injection combined with cross-sectional anatomical dissection.

RESULTS

This study identified bilaminar membranes traveling from deep to superficial fascia at consistent locations in all specimens. These membranes exist as fusion zones between superficial and deep fascia, and are referred to as SMAS fusion zones.

CONCLUSIONS

Nerves, blood vessels and lymphatics transition between the deep and superficial fascia of the face by traveling along and within these membranes, a construct that provides stability and minimizes shear. Bilaminar subfascial membranes continue into the subcutaneous tissues as unilaminar septa on their way to skin. This three-dimensional lattice of interlocking horizontal, vertical, and oblique membranes defines the anatomic boundaries of the fascial spaces as well as the deep and superficial fat compartments of the face. This information facilitates accurate volume augmentation; helps to avoid facial nerve injury; and provides the conceptual basis for understanding jowls as a manifestation of enlargement of the buccal space that occurs with age.

Successful Pedicled Anterolateral Thigh Flap Reconstruction for a Recurrent Ischial Pressure Ulcer: A Case With Multiple Recurrences Over a 7-year Follow-up

Ischial pressure ulcers are difficult ulcers to treat and have a low treatment success rate compared to sacral and trochanteric ulcers; regional flap failure further complicates the treatment. Reported here is a case of a 65-year-old man who experienced a spinal injury with paraplegia due to trauma 20 years ago. The patient experienced a recurrent ischial ulcer since 2007, and underwent several types of flap reconstruction with poor outcomes over a 7-year period. Therefore, the chosen intervention was a pedicled anterolateral thigh (pALT) fasciocutaneous flap reconstruction for the ischial ulcer via a subcutaneous route. Over the 10-month follow-up, the recurrent ischial ulcer healed without wound dehiscence. Island pALT reconstruction appears to be an alternative technique for treating recurrent ischial pressure ulcers. Though reconstruction of ischial ulcers via the pALT technique has been described previously, this may be the first case report to describe pALT flap in a patient with recurrent ischial ulcers after failed reconstructions using a gluteus maximus flap, V-Y advancement flap, and hatchet flap.Ischial pressure ulcers are difficult to treat and have a low treatment success rate1 compared to sacral and trochanteric ulcers. In addition, there are many different techniques that can be used to treat ischial pressure ulcers, including primary wound closure, gluteus maximus flaps, V-Y advancement flaps, or inferior gluteal artery perforator flaps. However, several experts have recently described using the pedicled anterolateral thigh (pALT) flap for reconstruction of recurrent ischial pressure ulcers.1,2 In the presented case, the authors followed a single patient with paraplegia with a recurrent ischial ulcer who had undergone several types of wound treatment over a 7-year period. The indurated ulcer was ultimately resolved by pALT reconstruction.

Histological assessment of non-ablative laser stimulation of tissue repair in acellular dermal grafts

AIM

The objective of this study was to compare integration of AlloDerm® acellular dermal grafts in animals subjected to non-ablative laser irradiation and animals not exposed to this therapy.

METHODS

Standardized AlloDerm® fragments measuring 5 mm² were grafted into the subcutaneous tissue overlying the calvaria in 32 Wistar rats. Laser therapy (685 ηm), at a dose of 4 J/cm2 per session, was applied immediately after surgical intervention and every 48 hours thereafter for a total of four applications.

RESULTS

Analysis of histology slides revealed significantly greater edema in the control group. There was no neutrophil infiltration in the laser-irradiated group at any point during the study period, whereas such infiltration was present in control animals at three of the four points of observation. In the laser therapy group, lymphocyte infiltration was observed from day 1, whereas in the control group, it was only apparent from day 3. Vascularization was substantially greater in the control group. In the experimental group, the AlloDerm® graft was completely replaced by fibrous tissue.

CONCLUSION

These findings suggest that add-on non-ablative laser therapy is an effective stimulator of healing and graft integration after placement of AlloDerm® acellular dermal grafts.

Influence of a specific, biorhythmically defined physical stimulus on deficient vasomotion in small-caliber arterioles in the subcutis in patients with diabetic polyneuropathy

As part of a placebo-controlled study series on a random sample of patients with diabetic polyneuropathy and trophic skin lesions on the edge of the foot, functional characteristics of the local microcirculation and immune system were measured to check the complementary-therapy success of biorhythmically defined vasomotion stimulation. Over a 30-day treatment period, complementary-therapy success was demonstrated for an additional physical vasomotion stimulation to increase the therapeutic success of established treatment concepts.

High-contrast subcutaneous vein detection and localization using multispectral imaging

Multispectral imaging has shown promise in subcutaneous vein detection and localization in human subjects. While many limitations of single-wavelength methods are addressed in multispectral vein detection methods, their performance is still limited by artifacts arising from background skin reflectance and optimality of postprocessing algorithms. We propose a background removal technique that enhances the contrast and performance of multispectral vein detection. We use images acquired at visible wavelengths as reference for removing skin reflectance background from subcutaneous structures in near-infrared images. Results are validated by experiments on human subjects.

In vivo and in vitro hemostatic activity of Chromolaena odorata leaf extract

CONTEXT

Chromolaena odorata (L.) R.M.King & H.Rob. (Asteraceae) or Siam weed has long been used to stop bleeding in Thailand and many countries. Only the aqueous leaf extract was investigated in in vivo and there have been conflicting results of in vitro hemostatic mechanisms of this plant.

OBJECTIVE

The most appropriate C. odorata leaf extract that promoted the highest hemostatic activity and the hemostatic mechanisms of these plant extracts will be investigated.

MATERIALS AND METHODS

The lyophilized aqueous leaf extract and alcoholic (50, 70, and 95% ethanol) extracts from the fresh and dried leaves were investigated both in vivo and in vitro. The bleeding time in male Wistar rats was measured to investigate the hemostatic effect. The hemostatic mechanisms were tested using in vitro platelet aggregation and blood coagulation tests in sheep plasma.

RESULTS

All extracts displayed significantly reducing bleeding time (<2.5 min) in rats but did not induce platelet aggregation or blood clotting in the in vitro study. The in vitro blood clotting times of all extracts were >0.6 min. Ethanol extract (70%) from the dried leaves proved to be the extract producing the highest hemostatic activity in vivo with the bleeding time of 1.85 min.

DISCUSSION AND CONCLUSION

The in vivo study with rats confirmed the significant ability of this plant extract to stop bleeding. However, the sufficient amount of calcium and active compounds which are aggregating and clotting agents to enhance blood coagulation and platelet aggregation in in vitro tests should be further studied.

[Endovasal obliteration of the main subcutaneous veins - a mechanism of action]

Active dissemination implementation of endovascular methods has during the past decade been a progressive tendency of the development of surgical treatment management of varicose disease.Amongst these methods, endovasal laser obliteration in Russia occupies the leading place. Despite widespread implementation of this method into clinical practice still there are neither common concepts on the mechanisms of action of laser energy, inducing lesions of the venous wall followed by obliteration, nor, consequently,criteria for administration thereof The search for an optimal method and mode of intravascular intervention is based on study-ing the mechanisms of the damaging action of laser energy on the venous wall. The article contains a literature review of the studies dedicated to investigating the mechanisms of action of endovasal methods of treatment for varicose disease.

[Tissue oxygen exchange and oxidative processes in long-livers: age peculiarities]

This work was undertaken to study tissue oxygen exchange and oxidative processes in the long-lived individuals who were assumed as the physiologically aging individuals. Oxygen tension was assessed in forearm subcutaneous cellular tissue by means of the polarographic method while performing 10 min oxygen inhalation tests (with spontaneous oxygemogram recording) and a 10 min clamping of vessels. The obtained data served as the tissue oxygen exchange indicator. This approach made us possible to evaluate the oxygen delivery and oxygen uptake. To study qualitative characteristics of oxidative processes, we assessed vacat-oxygen of the blood and urine and estimated the underoxidation coefficient proposed by Muller. We have found that tissue respiration intensity falls, the amount of underoxidated products of the blood and urine rises, and the underoxidation coefficient increases in aging. The decrease of tissue oxygen respiration intensity in subcutaneous cellular tissue reflects the development of tissue hypoxia associated with reduced activity of the enzymes, being involved in oxygen exchange. An age-related decrease of tissue perfusion leads to the formation of circulatory hypoxia and also contributes considerably to tissue hypoxia formation. The revealed changes in the tissue oxygen exchange and oxidative processes in the long-livers are generally correspondent to those that can be seen in the people of 80-89 years. This finding speaks in favor of the physiological aging in the long-livers.

Subcutaneous fascial bands--a qualitative and morphometric analysis

Background

Although fascial bands within the subcutaneous (SQ) layer are commonly seen in ultrasound images, little is known about their functional role, much less their structural characteristics. This study's objective is to describe the morphological features of SQ fascial bands and to systematically evaluate the bands using image analyses tools and morphometric measures.

Methods

In 28 healthy volunteers, ultrasound images were obtained at three body locations: the lateral aspect of the upper arm, medial aspect of the thigh and posterior aspect of lower leg. Using image analytical techniques, the total SQ band area, fascial band number, fascial band thickness, and SQ zone (layer) thickness were determined. In addition, the SQ spatial coherence was calculated based on the eigenvalues associated with the largest and smallest eigenvectors of the images.

Results

Fascial bands at these sites were contiguous with the dermis and the epimysium forming an interconnected network within the subcutaneous tissue. Subcutaneous blood vessels were also frequently encased by these fascial bands. The total SQ fascial band area was greater at the thigh and calf compared to the arm and was unrelated to SQ layer (zone) thickness. The thigh was associated with highest average number of fascial bands while calf was associated with the greatest average fascial band thickness. Across body regions, greater SQ zone thickness was associated with thinner fascial bands. SQ coherence was significantly associated with SQ zone thickness and body location (calf with statistically greater coherence compared to arm).

Conclusion

Fascial bands are structural bridges that mechanically link the skin, subcutaneous layer, and deeper muscle layers. This cohesive network also encases subcutaneous vessels and may indirectly mediate blood flow. The quantity and morphological characteristics of the SQ fascial band may reflect the composite mechanical forces experienced by the body part.

Relaxin induces rapid dilation of rodent small renal and human subcutaneous arteries via PI3 kinase and nitric oxide

The peptide hormone relaxin is a potent vasodilator with therapeutic potential in diseases complicated by vasoconstriction, including heart failure. However, the molecular mediators and magnitude of vasodilation may vary according to duration of exposure and artery type. The objective of these studies was to determine mechanisms of rapid (within minutes) relaxin-induced vasodilation and to examine whether relaxin dilates arteries from different animal species and vascular beds. Rat and mouse small renal, rat mesenteric, and human sc arteries were isolated, mounted in a pressure arteriograph, and treated with recombinant human relaxin (rhRLX; 1-100 ng/ml) after preconstriction with phenylephrine. Rat and mouse small renal as well as human sc arteries dilated in response to rhRLX, whereas rat mesenteric arteries did not. Endothelial removal or pretreatment with l-N(G)-monomethyl arginine (L-NMMA) abolished rapid relaxin-induced vasodilation; phosphatidylinositol-3-kinase (PI3K) inhibitors also prevented it. In cultured human endothelial cells, rhRLX stimulated nitric oxide (assessed using 4-amino-5-methylamino-2'7'-difluorofluorescein) as well as Akt and endothelial NO synthase (eNOS) phosphorylation by Western blotting but not increases in intracellular calcium (evaluated by fura-2). NO production was attenuated by inhibition of Gα(i/o) and Akt (using pertussis toxin and the allosteric inhibitor MK-2206, respectively), PI3K, and NOS. Finally, the dilatory effect of rhRLX in rat small renal arteries was unexpectedly potentiated, rather than inhibited, by pretreatment with the vascular endothelial growth factor receptor inhibitor SU5416. We conclude that relaxin rapidly dilates select arteries across a range of species. The mechanism appears to involve endothelial Gα(i/o) protein coupling to PI3K, Akt, and eNOS but not vascular endothelial growth factor receptor transactivation or increased calcium.

Blood flow in the foreign-body capsules surrounding surgically implanted subcutaneous devices

BACKGROUND

Surgically implanted devices initiate inflammatory mechanisms and wound healing events and result in the formation of a thick fibrotic capsule that surrounds the device. To investigate the foreign-body response to devices of clinically relevant size, we used microspheres to determine regional blood flow patterns in the foreign-body capsule (FBC) and surrounding subcutaneous tissue after device implantation.

MATERIALS AND METHODS

In 10 canines, we implanted 40 subcutaneous devices (polysulfone n = 20, silicone-coated n = 10, titanium n = 10). Via thoracotomy, animals were instrumented with left atrial and aortic vascular access catheters for serial microsphere injections and reference blood sampling. Regional blood flow was repeatedly determined in the FBC, subcutaneous fascia surrounding the FBC, and subcutaneous fascia distal to the surgical site up to 19 wk after device implantation (n = 55 determinations).

RESULTS

Compared with normal blood flow in subcutaneous fascia distal to the surgical site, blood flow increased in FBCs surrounding each device material (polysulfone P = 0.0035, silicone-coated P < 0.0001, titanium P < 0.0001). Additionally, blood flow increased in the subcutaneous fascia within half a centimeter of fibrous capsules encasing polysulfone (P = 0.0081) but not silicone (P = 0.3706) or titanium (P = 0.8160) devices. The time-course of measured blood flow changes within FBCs were similar for polysulfone and silicone but not for titanium.

CONCLUSIONS

Surgically implanted subcutaneous devices of clinically relevant size elicit increases in blood flow in the FBC as well as surrounding fascia. Device material may influence regional blood flow patterns.

[Treatment of nonunion of tibia with superficial peroneal vascular fascia pedicel tibiofibular periosteal flap]

OBJECTIVE

To investigate the surgical treatment method and the curative effect of tibial nonunion with superficial peroneal vascular fascia pedicel tibiofibular periosteal flap.

METHODS

From January 1996 to December 2008, 18 cases of tibial nonunion were treated with superficial peroneal vascular fascia pedicel tibiofibular periosteal flap, interlocking intramedullary nailing and cancellous bone graft of distal tibial. There were 14 males and 4 females, with an average age of 32.5 years old (range, 24-67 years old). Fracture site was middle in 10 cases and distal in 8 cases. Primary injury cause included 12 cases of traffic accident and 6 cases of bruise. The tibial nonunion reasons were manual reduction and plaster immobilization in 8 cases, small splint immobilization in 4 cases, intramedullary nail fixation in 2 cases (no bone graft), plate fixation in 4 cases (including 3 cases of plate fixation and free iliac bone graft). Nonunion occurred after the first surgery. The time from nonunion to operation was 8 to 16 months, with an average of 10.5 months. The size of periosteal flap was 7 cm x 5 cm and distal tibial cancellous bone graft volume was 5-10 g.

RESULTS

All incision achieved healing by first intention after operation without flap necrosis and infection. All patients were followed up 6-36 months with an average of 20.8 months. All tibial nonunion healed 5-7 months after operation. According to Johner-Wruh scoring, the results were excellent in 14 cases, good in 3 cases, and fair in 1 case; the excellent and good rate was 94.4%.

CONCLUSION

Superficial peroneal vascular tibiofibularfascia pedicel tibiofibular periosteal flap and interlocking intramedullary nailing can attain good results in treating nonunion of tibia and fibula because of being stable internal fixation and promoting the healing of nonunion.

Relationship between parameters of air plethysmography and types of superficial venous reflux in patients with primary varicose veins

AIM

We investigated whether parameters of air plethysmography (APG) were correlated with types of superficial venous reflux as categorized by ascending venography in patients with primary varicose veins.

METHODS

Two hundred and eight limbs with primary varicose veins in 135 patients were evaluated by both APG and ascending venography. Venous hemodynamics was assessed with APG. The location of incompetent vein segments was determined based on the results of ascending venography.

RESULTS

Seventy-seven limbs had incompetence of the greater saphenous vein (GSV, G group), 36 had incompetence of the lesser saphenous vein (LSV, L group), and 77 had incompetence of the GSV and LSV (GL group). Twenty-five limbs did not have incompetence of the GSV or LSV (N group). The venous filling index (VFI) differed significantly between the N and the G and GL groups, the L group and the G and GL groups, and the G and GL groups. No significant difference was found between the N and L groups. The venous volume, ejection fraction, and residual volume fraction did not differ significantly among all four groups.

CONCLUSION

The VFI as measured by APG discriminates well between limbs with incompetence of the GSV and those without incompetence of the GSV or LSV, and between limbs with incompetence of the GSV and those with the LSV in patients with primary varicose veins, suggesting that the hemodynamic severity of superficial venous reflux progresses with involvement from the LSV to the GSV to both saphenous veins.

Matrix metalloproteinase-9 is required for tumor vasculogenesis but not for angiogenesis: role of bone marrow-derived myelomonocytic cells

Tumor vasculature is derived from sprouting of local vessels (angiogenesis) and bone marrow (BM)-derived circulating cells (vasculogenesis). By using a model system of transplanting tumors into an irradiated normal tissue to prevent angiogenesis, we found that tumors were unable to grow in matrix metalloproteinase-9 (MMP-9) knockout mice, but tumor growth could be restored by transplantation of wild-type BM. Endothelial progenitor cells did not contribute significantly to this process. Rather, CD11b-positive myelomonocytic cells from the transplanted BM were responsible for tumor growth and the development of immature blood vessels in MMP-9 knockout mice receiving wild-type BM. Our results suggest that MMP-9 could be an important target for adjunct therapy to enhance the response of tumors to radiotherapy.

Effects of erythrocyte flexibility on microvascular perfusion and oxygenation during acute anemia

Responses to exchange transfusion using red blood cells (RBCs) with normal and reduced flexibility were studied in the hamster window chamber model during acute moderate isovolemic hemodilution to determine the role of RBC membrane stiffness in microvascular perfusion and tissue oxygenation. Erythrocyte stiffness was increased by 30-min incubation in 0.02% glutaraldehyde solution, and unreacted glutaraldehyde was completely removed. Filtration pressure through 5-μm pore size filters was used to quantify stiffness of the RBCs. Anemic conditions were induced by two isovolemic hemodilution steps using 6% 70-kDa dextran to a hematocrit (Hct) of 18% (moderate hemodilution). The protocol continued with an exchange transfusion to reduce native RBCs to 75% of baseline (11% Hct) with either fresh RBCs (RBC group) or reduced-flexibility RBCs (GRBC group) suspended in 5% albumin at 18% Hct; a plasma expander (6% 70-kDa dextran; Dex70 group) was used as control. Systemic parameters, microvascular perfusion, capillary perfusion [functional capillary density (FCD)], and oxygen levels across the microvascular network were measured by noninvasive methods. RBC deformability for GRBCs was significantly decreased compared with RBCs and moderate hemodilution conditions. The GRBC group had a greater mean arterial blood pressure (MAP) than the RBC and Dex70 groups. FCD was substantially higher for RBC (0.81 ± 0.07 of baseline) vs. GRBC (0.32 ± 0.10 of baseline) and Dex70 (0.38 ± 0.10 of baseline) groups. Microvascular tissue Po2 was significantly lower for Dex70 and GRBC vs. RBC groups and the moderate hemodilution condition. Results were attributed to decreased oxygen uploading in the lungs and obstruction of tissue capillaries by rigidified RBCs, indicating that the effects impairing RBC flexibility are magnified at the microvascular level, where perfusion and oxygenation may define transfusion outcome.

Changes in the rat subcutaneous connective tissue after saline and histamine injection in relation to fluid storage and excretion

An experimental design was developed for morphometric analysis of the subcutaneous connective tissue after the subcutaneous injection of 0.1 ml of saline or a histamine solution (0.01, 0.1 or 1% histamine dihydrochloride in saline). The subcutaneous connective tissue of 4-week-old rats, originally 170.0 +/- 13.6 mum in thickness, swelled 5.2-fold at 15 min, 3.0-fold at 2 h, and 1.2-fold at 6 h after the injection of saline. The total cross sectional area of both blood and lymphatic vessels increased when compared to that at pre-injection (0.0186 +/- 0.0030 mm(2) in 6-mm-long specimen), 1.4-fold at 15 min, 2.2-fold at 2 h, and 1.1-fold at 6 h post-injection, while the total number of these vessels increased 1.1-fold at 2 h. The total cross sectional area of lymphatic vessels (0.0006 +/- 0.0002 mm(2) in 6-mm-long specimen) alone surged 7.7-fold at 15 min, 4.8-fold at 2 h, and 7.3-fold at 6 h. Collagen fibers were respectively highly, moderately, and mildly disorganized in arrangement at 15 min, 2 h, and 6 h after the saline injection. Histamine elicited an earlier, longer, and more pronounced vasodilatation, particularly at high concentrations. The transvascular permeability of Evans blue increased depending on the concentration of histamine. These findings indicate that the subcutaneous connective tissue has the ability to expand and store a considerable amount of fluid and reversibly returns to normal steady-state conditions by increasing fluid excretion into the blood and lymphatic vessels. It was also strongly suggested that the blood vessels are deeply involved in the excretion and volume regulation of the tissue fluid.

Intravenous fluorescein vascularity studies of a new technique: the subcutaneous pedicled extension flap

OBJECTIVE

To prove the vascularity of the subcutaneous pedicled extension flap through the subcutaneous pedicle. Second, the study was designed to reveal increasing vascularity as a function of time during the intraoperative period.

DESIGN

Twenty-six cases of flap utility are presented. The last 11 of these cases were tested for intraoperative vascularity using intravenous fluorescein sodium. Following a 1-mL (100-mg) fluorescein sodium test dose, an additional 900 mg was administered intraoperatively. The fluorescence was observed and photographed at 15-, 30-, and 60-minute intervals. The fluorescence (or lack thereof) was easily visible to the naked eye relative to the surrounding skin, requiring no specialized measurements. Photographic equipment consisted of a 35-mm camera with a UV filter, using 400 ASA-rated film at a 1-second timed setting. A tripod was necessary.

SETTING

All cases were performed in either an ambulatory surgical facility or an in-hospital facility.

PATIENTS

All patients suffered from skin cancer requiring large resections, necessitating reconstruction via either grafts or flaps.

INTERVENTION

Intravenous 10% fluorescein (Fluorescite) was used as a vascularity testing mode. The method was as described in the "Subjects and Methods" section.

MAIN OUTCOME MEASURES

The results revealed conclusively the vascularity of the flap through the subcutaneous pedicle. In addition, the secondary goal, ie, of showing increasing vascularity with time, was also proved.

RESULTS

The subcutaneous flaps have survived in all cases, with minimal complications. The intravenous fluorescein test, with timed applications intraoperatively, has been reaffirmed as an excellent prognosticator of survivability, as well as a confirmation of the innate vascularity of the subcutaneous pedicle.

CONCLUSIONS

The subcutaneous pedicled extension is thought to be a new development in random flaps. Its vascularity via the subcutaneous pedicle has been conclusively confirmed using the safe and simple intravenous fluorescein intraoperative study. Second, increasing fluorescence on a timed basis has been reaffirmed and this degree of vascularity related to the ease of survival of the flap.

Experimental Study of Autologous Cartilage, Acellular Cadaveric Dermis, Lyophilized Bovine Pericardium, and Irradiated Bovine Tendon

The purpose of this study was to compare the volumetric and histologic changes of the acellular cadaveric dermis, lyophilized bovine pericardium, irradiated bovine tendon, and autologous cartilage transplanted subcutaneously in the rats. Four different kinds of implants were placed in subcutaneous pockets of the dorsum of 40 Wister rats. The implants with the subcutaneous pockets were retrieved in the first, fourth, eighth, and 12th weeks after implantation. The size and histologic change of each implant were observed. The xiphoid cartilage showed the peak survival (71.0%, P = 0.247) on the 12th week, but part of the cartilage was absorbed irregularly and its shape changed unpredictably. The lyophilized bovine pericardium had a high survival rate as well (64.4%, P = 0.016). However, the size decreased significantly in the first through 12th weeks. A survival of acellular cadaveric dermis was lower (38.8%, P = 0.036) than the cartilage and pericardium, but it sustained the structure for 12 weeks and changed peripherally into the neocollagen. Irradiated bovine tendon disclosed the lowest survival rate (31.4%, P = 0.008). The structure was gradually distorted and replaced entirely by neocollagen in the 12th week after implantation. Autologous cartilage is the best choice for soft tissue and nasal tip augmentation. Although other implants than the cartilage showed significant diminution of its volume in 12 weeks, lyophilized bovine pericardium could be the next substitute to the cartilage in soft tissue augmentation.

Excessive erythrocytosis does not elevate capillary oxygen delivery in subcutaneous mouse tissue

OBJECTIVE

Acclimatization to reduced environmental oxygen includes erythropoietin-regulated increase in erythrocytes enhancing the blood's oxygen content. However, increased hematocrit levels result in elevated blood viscosity that might impair microcirculation and tissue oxygenation. To assess this oxygen supply to the skin, the authors used erythropoietin overexpressing transgenic mice (tg6) that develop excessive erythrocytosis in an oxygen-independent manner. These animals have been previously reported to elevate their blood viscosity 4-fold.

METHODS

The partial oxygen pressure (pO2) distribution was evaluated in microvessels as well as in subcutaneous interstitial tissue within a dorsal skinfold chamber of resting conscious mice using automated phosphorescence quenching.

RESULTS

Compared to wildtype (wt) animals, transgenic blood viscosity increased 4-fold but microvessel diameter was not altered. Despite sharing similar blood pO2 as the wt siblings, tg6 animals nearly doubled their oxygen content. Moreover, tg6 erythrocytes reduced hemoglobin's oxygen affinity by decreased 2,3-DPG levels and an increased Hill number. Transgenic arterioles and venules showed increased pO2 compared to wt controls whereas capillary and tissue pO2 were not altered.

CONCLUSIONS

Excessive erythrocytosis does not elevate capillary oxygen delivery.

CNP, but not ANP or BNP, relax human isolated subcutaneous resistance arteries by an action involving cyclic GMP and BKCa channels

Natriuretic peptides play an important role in sodium regulation and blood pressure (BP) control. We examined the effects of atrial natriuetic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) on human isolated resistance arteries and the mechanisms involved in vasorelaxation. Human subcutaneous resistance arteries were mounted in an isometric myograph and contracted with phenylephrine. CNP, but not ANP or BNP, relaxed arteries in a concentration dependent manner. The action of CNP was unaffected by removal of the endothelium, inhibition of nitric oxide synthase by NG-monomethyl-Larginine or inhibition of soluble guanylate cyclase by 1H-[1,2,4] oxadiazolo [4,3-alpha] quinoxalin-1-one. Blockade of cyclic GMPdependent kinase by 8- bromoguanosine- 3, 5- cyclic monophosphorothioate, Rp-isomer (Rp-8-Br-cGMPS) inhibited CNP relaxation. CNP relaxation was also inhibited by high potassium or iberiotoxin, indicating that it was due to opening of BKCa channels. Omapatrilat, a vasopeptidase inhibitor of neutral endopeptidase and angiotensin-converting enzyme, enhanced the effect of CNP and inhibited responses to Ang I. In summary, CNP, but not ANP or BNP, relaxes human resistance arteries by activating cyclic GMP-dependent kinase and BKCa. The effects of CNP are enhanced by vasopeptidase inhibition and this may contribute to the vasodilator effects of these agents in vivo. Since CNP is widely present in endothelium it may play a role in the regulation of peripheral resistance in man in physiological and pathological circumstances.

Host Immune Competence and Local Ischemia Affects the Functionality of Engineered Vasculature

OBJECTIVE

Localized and sustained delivery of vascular endothelial growth factor (VEGF) is a promising approach to overcome the limited efficacy of bolus delivery. The authors examined the effects of host immune competence and local ischemia on the functionality of new vessel networks formed with this approach.

METHODS

Vessel structure and perfusion resulting from implantation of porous 85:15 poly(lactide-co-glycolide) scaffolds releasing VEGF165 were measured in both subcutaneous tissue and ischemic hindlimbs of immune competent C57BL/6 and immune deficient SCID mice.

RESULTS

Sustained VEGF delivery resulted in a similar approximately 100% increase in vessel density within scaffolds in both implant sites, and both animal models. However, the resulting perfusion within scaffolds implanted in subcutaneous tissue increased modestly versus control (18-35%), while perfusion increased 52-110% above control when VEGF-releasing scaffolds were placed in ischemic hindlimbs of C57BL/6 or SCID mice. VEGF delivery improved perfusion in the entire ischemic limb (55 +/- 18% of the normal value by week 6; 138% increase over control) in SCID mice. Although C57BL/6 mice demonstrated spontaneous recovery from ischemia, VEGF delivery accelerated recovery as compared to control.

CONCLUSIONS

Localized and sustained VEGF delivery can create functional vasculature that amplifies recovery of tissue ischemia. However, increases in local and regional perfusion were highly dependent on the implantation site and the animal model.

Lebectin, aMacrovipera lebetina venom-derived C-type lectin, inhibits angiogenesis both in vitro and in vivo

Integrins play an essential role in endothelial cell motility processes during angiogenesis and thus present interesting targets for the development of new anti-angiogenic agents. Snake venoms naturally contain a variety of proteins that can affect integrin-ligand interactions. Recently, the C-type lectin proteins (CLPs) have been characterized as efficient modulators of integrin functions. In this study, we investigated the anti-angiogenic activity of lebectin, a newly discovered CLP from Macrovipera lebetina venom. Human brain microvascular endothelial cells (HBMEC), used as an in vitro model, express alphavbeta3, alphavbeta5, and alpha5beta1 integrins, as well as the alpha2, alpha3, alpha6, and beta4 subunits. Our data show that lebectin acts as a very potent inhibitor (IC(50) approximately 0.5 nM) of HBMEC adhesion and migration on fibronectin by blocking the adhesive functions of both the alpha5beta1 and alphaV integrins. In addition, lebectin strongly inhibits both HBMEC in vitro tubulogenesis on Matrigel trade mark (IC(50) = 0.4 nM) and proliferation. Finally, using both a chicken CAM assay and a Matrigel trade mark Plug assay in nude mice, our results show that lebectin displays potent anti-angiogenic activity in vivo. Lebectin thus represents a new C-type lectin with anti-angiogenic properties with great potential for the treatment of angiogenesis-related diseases.

Effect of acetyl 11-keto beta-boswellic acid on metastatic growth factor responsible for angiogenesis

Basic fibroblast growth factor (bFGF), a metastatic growth factor is known to be one of the promoting factors in the tumor induced angiogenesis. The antiangiogenic activity of acetyl 11-keto beta-boswellic acid was screened against bFGF-induced angiogenesis using in-vivo Matrigel Plug Assay. Histological & colorimetric examination confirmed that numerous blood vessels were present in Matrigel+bFGF group in comparison to Matrigel alone treated mice. Acetyl 11-keto beta-boswellic acids (10 mg/kg/d) inhibited the Matrigel+bFGF-induced angiogenesis significantly (P<0.01) in contrast to anti-inflammatory agent indomethacin (10 mg/kg/d) and alkylating agent cyclophosphamide (10 mg/kg/d).

Plexiform vascular structures in the human digital dermal layer: A SEM – corrosion casting morphological study

This study aimed to describe the impressive diversity of vascular plexiform structures of the hypodermal layer of human skin. We chose the human body site with the highest concentration of dermal corpuscles, the human digit, and processed it with the corrosion casting technique and scanning electron microscopy analysis (SEM). This approach proved to be the best tool to study these microvascular architectures, free from any interference by surrounding tissues. We took high-definition pictures of the vascular network of sweat glands, thermoreceptorial and tactile corpuscles, the vessels constituting the glomic bodies and those feeding the hair follicles. We observed that the three-dimensional disposition of these vessels strictly depends on the shape of the corpuscles supplied. We could see the tubular vascularization of the excretory duct of sweat glands and the ovoid one feeding their bodies, sometimes made up of two lobes. In some cases, knowledge of these morphological data regarding the normal disposition in space and intrinsic vascularization structure of the dermal corpuscles can help to explain many of the physiopathological changes occurring during chronic microangiopathic diseases.

Anatomical and radiological study of the superior and inferior gluteal arteries in the gluteus maximus muscle for musculocutaneous flap in Koreans

The position, distribution pattern, and perforating branch of the superior gluteal artery (SGA) and the inferior gluteal artery (IGA) in the gluteus maximus muscle (GMM) were investigated through fine dissection and the radiological method. The SGA was located at about the upper one-third of the posterior superior iliac spine (PSIS)-greater trochanter of the femur (GT) line and medially at about 1cm from the line. The IGA was located at around the middle point of the PSIS-ischial tuberosity (IT) line. The perforating branches passed through the muscle to the subcutaneous tissue and were distributed to the GMM that divided the upper and lower parts; the SGA supplied to the upper two-fifths of the GMM; and the IGA supplied to the rest of the muscle. The course of the SGA and the IGA in the GMM were classified into four types according to their distribution patterns, and the most common type was the typical type whereby the IGA supplied an area larger than the SGA. These results were somewhat different from previous studies, but these differences must be considered for a safe and effective flap procedure.

The Vasorelaxant Effect of Adrenomedullin, Proadrenomedullin N-Terminal 20 Peptide and Amylin in Human Skin

In this study we aimed to assess in vivo, the vasodilator effects of adrenomedullin, proadrenomedullin N-terminal 20 peptide (PAMP) and amylin in human skin vasculature and compare the responses to the effects mediated by the endogenous neuropeptides calcitonin gene-related peptide (CGRP) and substance P and to examine the mRNA expression of calcitonin receptor-like receptor (CL-R) and receptor-activity modifying proteins, RAMP1, RAMP 2 and RAMP3 in human subcutaneous arteries. Changes in skin blood flow of the forearm were measured using a Laser Doppler Imager after intradermal injection of the peptides. The mRNA expression was assessed by real-time reverse transcriptase-polymerase chain reaction (real-time PCR). CGRP, adrenomedullin and amylin induced concentration-dependent, long-lasting increases in skin blood flow. The response to PAMP was shorter in duration appearing similar to the transient response induced by substance P. PAMP (10(-6)-10(-5) M) caused distinct itch sensation and local erythema. This effect could be abolished when combining the histamine H1-receptor antagonist mepyramin and PAMP. Real-time PCR data showed a higher level of mRNA for RAMP2 than CL-R, RAMP1 and RAMP3 in the tissue. Though the PCR data demonstrated the presence of mRNA for both CGRP1 and adrenomedullin receptors the rank order of potency (CGRP>adrenomedullin>amylin) for the blood flow increase indicated vasodilatation for these peptides was induced by activation of CGRP1 receptors. Intradermal injection of CGRP, adrenomedullin and amylin induces long lasting dilatation of human skin vasculature by activation of CGRP1 receptors. PAMP induces transient vasodilatation. PAMP but not CGRP, adrenomedullin and amylin causes itch sensation and local erythema. The transient effect on vasodilatation as response to PAMP is discussed.

Angiotensin Receptor Blocker Added to Previous Antihypertensive Agents on Arteries of Diabetic Hypertensive Patients

Lowering elevated blood pressure (BP) in diabetic hypertensive individuals decreases cardiovascular events. We questioned whether remodeling of resistance arteries from hypertensive diabetic patients would improve after 1 year of tight BP control with addition of either the angiotensin receptor blocker (ARB) valsartan or the β-blocker (BB) atenolol to previous therapy, which included angiotensin-converting enzyme inhibitors (ACEIs) and/or calcium channel blockers. Twenty-eight hypertensive type 2 diabetic patients treated with oral hypoglycemic and antihypertensive agents (not receiving ARBs or BBs) were randomly assigned to double-blind treatment for 1 year with valsartan (80 to 160 mg) or atenolol (50 to 100 mg) daily, added to previous therapy. Resistance arteries dissected from gluteal subcutaneous tissues were assessed on a pressurized myograph. After 1 year of treatment, systolic and diastolic BP and glycemia were equally well controlled in the valsartan and atenolol groups. Endothelium-dependent and independent relaxation did not change in the treated groups. After 1 year of treatment, resistance artery media:lumen ratio decreased in the valsartan group (7.9±0.5% after versus 9.8±0.6% before; P <0.05) but not in the atenolol-treated group (9.9±0.9% versus 10.6±1%; P value not significant). Artery walls from atenolol-treated patients became stiffer, with no change in the valsartan-treated patients. In conclusion, similar intensive BP control for 1 year with valsartan was associated with improved structure of resistance arteries in diabetic hypertensive patients, whereas vessels from atenolol-treated patients exhibited unchanged remodeling and a stiffer wall. The addition of ARBs but not BBs to antihypertensive medications that may include angiotensin-converting enzyme inhibitors and/or calcium channel blockers results in an improvement in resistance artery remodeling in diabetic hypertensive patients.

Sulforaphane suppresses angiogenesis and disrupts endothelial mitotic progression and microtubule polymerization

Sulforaphane (SUL), an isothiocyanate derived from broccoli and other cruciferous vegetables, is known to induce phase II detoxification enzymes, disrupt cancer cell microtubule polymerization, and trigger cell cycle arrest in breast and colon cancer cells. Here, we provide the first evidence that SUL also acts to inhibit angiogenesis via suppression of endothelial cell proliferation. Bovine aortic endothelial (BAE) cells were exposed to concentrations of up to 15 microM SUL prior to cell cycle analysis and mitotic index quantification. Within 24 h, 15 microM SUL clearly induced G(2)/M accumulation and pre-metaphase arrest in BAE cells. Moreover, immunofluorescence tubulin staining indicated that this same SUL concentration was efficacious in not only disrupting mitotic progression, but also in perturbing normal polymerization of mitotic (and cytoplasmic) microtubules. Furthermore, daily administration of SUL (100 nmol/day, i.v. for 7 days) to female Balb/c mice bearing VEGF-impregnated Matrigel plugs strongly and significantly (P<0.05) suppressed angiogenesis progression as measured by hemoglobin concentration. Taken together, these findings suggest that the endothelial cell population is a novel target of SUL action both in vitro and in vivo. This mechanism of SUL-induced endothelial microtubule disruption and early mitotic arrest may further discern a potential role of SUL as a chemopreventive agent.

Tissue oxygenation response to mild hypercapnia during cardiopulmonary bypass with constant pump output

BACKGROUND

Tissue oxygenation is the primary determinant of wound infection risk. Mild hypercapnia markedly improves cutaneous, subcutaneous (s.c.), and muscular tissue oxygenation in volunteers and patients. However, relative contributions of increased cardiac output and peripheral vasodilation to this response remains unknown. We thus tested the hypothesis that increased cardiac output is the dominant mechanism.

METHODS

We recruited 10 ASA III patients, aged 40-65 yr, undergoing cardiopulmonary bypass for this crossover trial. After induction of anaesthesia, a Silastic tonometer was inserted s.c. in the upper arm. S.C. tissue oxygen tension was measured with both polarographic electrode and fluorescence-based systems. Oximeter probes were placed bilaterally on the forehead to monitor cerebral oxygenation. After initiation of cardiopulmonary bypass, in random order patients were exposed to two arterial CO(2) partial pressures for 30 min each: 35 (normocapnia) or 50 mm Hg (hypercapnia). Bypass pump flow was kept constant throughout the measurement periods.

RESULTS

Hypercapnia during bypass had essentially no effect on Pa(CO(2)) , mean arterial pressure, or tissue temperature. Pa(CO(2)) and pH differed significantly. S.C. tissue oxygenation was virtually identical during the two Pa(CO(2)) periods [139 (50-163) vs 145 (38-158), P=0.335] [median (range)]. In contrast, cerebral oxygen saturation (our positive control measurement) was significantly less during normocapnia [57 (28-67)%] than hypercapnia [64 (37-89)%, P=0.025].

CONCLUSIONS

Mild hypercapnia, which normally markedly increases tissue oxygenation, did not do so during cardiopulmonary bypass with fixed pump output. This suggests that hypercapnia normally increases tissue oxygenation by increasing cardiac output rather than direct dilation of peripheral vessels.

Rosiglitazone treatment increases subcutaneous adipose tissue glucose uptake in parallel with perfusion in patients with type 2 diabetes: a double-blind, randomized study with metformin

CONTEXT

We have shown that rosiglitazone increases whole-body and adipose tissue insulin sensitivity in humans.

OBJECTIVE

The aim of this study was to further examine whether possible changes in adipose perfusion could explain increased adipose tissue glucose uptake (GU).

PATIENTS

Thirty-seven patients with newly diagnosed type 2 diabetes were included.

INTERVENTION

Patients were randomized into treatment with rosiglitazone, metformin, or placebo for 26 wk in a double-blinded trial.

DESIGN

Femoral adipose flow and GU were measured with [15O]H2O, [18F]fluorodeoxyglucose and positron emission tomography during euglycemic hyperinsulinemia. Adipose masses were measured using magnetic resonance imaging.

RESULTS

Metformin and rosiglitazone treatment improved glycemic control, but only rosiglitazone increased whole-body insulin sensitivity. Rosiglitazone treatment increased flow by 72% (P < 0.01) and GU by 23% (P < 0.05) and thereby decreased adipose tissue glucose extraction by 18% (P < 0.05); no changes were observed in the metformin or placebo-treated groups. When the adipose masses were taken into account, rosiglitazone treatment increased flow by 73% (P < 0.01) and GU by 24% (P < 0.05). During hyperinsulinemia, flow correlated with GU (r = 0.63; P < 0.01).

CONCLUSIONS

In conclusion, s.c. GU is associated with flow in patients with type 2 diabetes. Rosiglitazone treatment enhances GU and flow but decreases glucose extraction, suggesting that perfusion may contribute to adipose tissue insulin sensitization by rosiglitazone.

Red blood cell and tissue water content in experimental thermal injury

Oedema formation and changes in local blood flow are known phenomena in burns. The relationship between these two is not clearly described. The aim of this study was firstly to examine both the contents of red blood cells and tissue water in skin and subcutaneous fat after experimental burns of different depths in pigs, and secondly, to confirm our recent findings of the increased dielectric constant of skin and subcutaneous fat reflecting considerable oedema formation, especially in fat after thermal injury.

METHODS

Superficial, partial and full thickness contact burns were created to pigs and followed for 24h. Radioactive Cr-51 labelling of red cells was used to estimate the number of red cells in tissue, and the absolute amount of water was determined by lyophilization.

RESULTS

A decreased number of labelled red cells in skin and an increase in tissue water in subcutaneous fat were found regardless of burn depth. The highest water amount in fat was found in the partial thickness burns.

CONCLUSION

All burn depths resulted in a diminished number of labelled red blood cells in skin and a significant increase in the absolute water amount in subcutaneous fat at 24h post injury. The findings in fat support our recent findings of highly elevated dielectric constants measured by the new in vivo method of dielectric measurements.

Hemangioma versus vascular malformation: presence of nerve bundle is a diagnostic clue for vascular malformation

CONTEXT

Arteriovenous vascular malformations and hemangiomas are benign vascular lesions that are difficult to distinguish from one another clinically. Also, they may be confused with each other at histopathology. Therefore, histochemical stains for the presence of an artery are frequently used to distinguish between the two.

OBJECTIVE

Because it is clinically relevant to differentiate between arteriovenous vascular malformations and hemangiomas, this study was carried out to explore additional diagnostic clues that may help in the diagnosis and differentiation of these lesions.

DESIGN

A total of 167 cases of benign extracranial vascular lesions were retrieved from the anatomic pathology file of our institution. These comprised 66 cases diagnosed as arteriovenous vascular malformations and 101 cases previously diagnosed as hemangiomas. The hematoxylin-eosin-stained glass slides were reviewed, Movat pentichrome histochemical stain was used to identify elastic vessels (arteries/arterioles), and S100 immunostain was used to identify nerves within these vascular lesions. For immunohistochemistry, the avidin-biotin detection method was used.

RESULTS

With Movat stain, the presence of thick-walled elastic arteries was detected in 12 of the 101 cases previously diagnosed as hemangiomas, and these cases were therefore reclassified as vascular malformations. Using the same criterion, 2 of the 66 cases originally diagnosed as arteriovenous vascular malformations were reclassified as hemangiomas because they lacked arterial structures. Thus, with this strict criterion, we ended up with 91 cases of hemangiomas and 76 cases of arteriovenous vascular malformations. Intralesional nerves were identified in 91% (69/76) of cases of arteriovenous vascular malformations, including all the 12 arteriovenous vascular malformations previously diagnosed as hemangiomas. In contrast, no intralesional nerve was detected in any of the 91 hemangiomas.

CONCLUSIONS

These results show that nerve bundles are consistently present in vascular malformations and absent in hemangiomas and so can be used as a diagnostic clue to differentiate between these lesions. Also, in addition to describing a previously unreported component of vascular malformations, these data further confirm the hamartomatous nature of these lesions.

Preadipocytes in the human subcutaneous adipose tissue display distinct features from the adult mesenchymal and hematopoietic stem cells

The stroma-vascular fraction (SVF) of human adipose tissue has recently been described to be composed of endothelial cells identified as CD34+/CD31+ cells, infiltrated/resident macrophages defined as CD14+/CD31+ cells, and a new cell population characterized as CD34+/CD31- cells. To elucidate the cell identity of the adipocyte precursor cells, fluorescent activating cell sorter (FACS) analyses were performed on crude SVF cultured under adipogenic conditions, i.e., serum-deprived medium containing insulin, cortisol, triiodothyronine, and supplemented with a PPARgamma agonist for the first 3 days. The progressive accumulation of lipid droplets was associated with a selective enrichment of the CD34+/CD31- cell population whereas control experiments performed in medium supplemented with 10% serum showed an overall downregulation of the three cell markers without adipogenesis. Among the different cell subsets, the CD34+/CD31- subset was the unique cell fraction able to answer to adipogenic culture conditions. Indeed, a time-dependent expression of adipocyte markers as well as acquisition of adipocyte-typical metabolic activities were observed. In parallel, the gene expression of lipogenic and lipolytic enzymes increased. The ability to differentiate into adipocytes was restricted to cells that did not express the mesenchymal stem cell marker CD105. Furthermore, the CD34+/CD31- cells did not respond to culture conditions used for hematopoietic colony assays. Taken together, the present study demonstrates that adipocyte progenitor cells, i.e., the preadipocytes, are included in the CD34+/CD31- cell fraction, which displays distinct features from the adult mesenchymal and hematopoietic stem cells.

Disseminated epitheloid hemangioendothelioma mimicking symptoms of systemic vasculitis

BACKGROUND

Epitheloid hemangioendothelioma is a rare malignant tumor which can involve bones, liver, lungs, kidneys, deep soft tissue, muscles, dermis, and central nervous system. Multifocal disease occurs in 10% of the cases. The clinical presentation results from occlusion of small blood vessels due to the disease itself or as a paraneoplastic syndrome.

CASE REPORT

We present a patient with symptoms suggesting systemic vasculitis (ESR and CRP elevated, weight loss, arthralgia, livedoid rash, and skin ulcerations) who finally was diagnosed having a disseminated epitheloid hemangioendothelioma when PET scan revealed hypermetabolic multifocal skeletal and soft tissue lesions.

DISCUSSION

Diseases mimicking systemic vasculitis and the value of PET in this setting are discussed.

Histological evaluation of Permacol as a subcutaneous implant over a 20-week period in the rat model

This study assessed the suitability of Permacol (a porcine derived, isocyanate cross linked collagen based biomaterial) as an alternative to autologous tissue in soft tissue reconstruction. The Sprague-Dawley rat was used as a model for subcutaneous implantation over a 20 week period and comparison made with two other porcine biomaterials (small intestinal submucosa and glycerol treated-ethylene oxide sterilised porcine dermis). Implants were scored histometrically on the degree of acute inflammation, chronic inflammation, fibrosis and stromal response. The vascularity and percentage composition of collagen within Permacol were assessed by stereology and seescan image analysis, respectively. In general terms, Permacol was well tolerated as a subcutaneous implant, with only a minor chronic inflammatory response remaining after a 20 week period of implantation. There was evidence of collagen degradation during this period and vascular ingrowth into Permacol was limited. Permacol has the potential for a broad range of applications in plastic surgery, but may benefit from modification to promote a more rapid degree of vascularisation.