Hyaluronic Acid by Atomic Force Microscopy

Jacoboni, I.; Valdrè, U.; Mori, G.; Quaglino, Daniela

doi:10.1006/jsbi.1999.4090

Cited by 39 publications

(24 citation statements)

References 17 publications

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“…Adding HA to the surfactants produced changes in the microscopic structure that were of a different nature than changes induced by PEG or dextran, and were associated with no clear decrease in viscosity. It has been shown that HA can interact with phospholipids to create large fibril-like networks [28, 29]. Our microscope observations indicate that surfactant with HA produces a reorganization of surfactant components to form an interconnected matrix of structures that occupies the whole suspension.…”

Section: Discussionmentioning

confidence: 61%

Kinematic viscosity of therapeutic pulmonary surfactants with added polymers

Pérez‐Gil

Taeusch

2009

Biochimica et Biophysica Acta (BBA) - Biomembranes

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The addition of various polymers to pulmonary surfactants improves surface activity in experiments both in vitro and in vivo. Although the viscosity of surfactants has been investigated, the viscosity of surfactant polymer mixtures has not. In this study, we have measured the viscosities of Survanta and Infasurf with and without the addition of polyethylene glycol, dextran or hyaluronan. The measurements were carried out over a range of surfactant concentrations using two concentrations of polymers at two temperatures. Our results indicate that at lower surfactant concentrations, the addition of any polymers increased the viscosity. However, the addition of polyethylene glycol and dextran to surfactants at clinically used concentrations can substantially lower viscosity. Addition of hyaluronan at clinical surfactant concentrations slightly increased Infasurf viscosity and produced little change in Survanta viscosity. Effects of polymers on viscosity correlate with changes in size and distribution of surfactant aggregates and the apparent free volume of liquid as estimated by light microscopy. Aggregation of surfactant vesicles caused by polymers may therefore not only improve surface activity as previously shown, but may also affect viscosity in ways that could improve surfactant distribution in vivo.

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Section: Discussionmentioning

confidence: 61%

Kinematic viscosity of therapeutic pulmonary surfactants with added polymers

Pérez‐Gil

Taeusch

2009

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…its hydrophilic properties has hydrophobic regions created by its molecular shape that could potentially serve as interaction sites for the hydrophobic surfactant proteins B and C (11). HA molecules can interact with each other and form various aggregates such as three-dimensional networks or isolated clumps (21,22). The properties of these forms depend on the concentration and molecular weight of HA in the aqueous solution.…”

Section: Discussionmentioning

confidence: 99%

Hyaluronan Reduces Surfactant Inhibition and Improves Rat Lung Function after Meconium Injury

Goerke

Clements

et al. 2005

Pediatr Res

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Hyaluronan (HA), an ionic polymer, is normally present in the alveolar subphase and is known to decrease lung surfactant inactivation caused by serum in vitro. In this study, we examined whether HA can ameliorate the inactivating effects of meconium in vitro and in vivo. Surface activities of various mixtures of Survanta, HA, and meconium were measured using a modified pulsating bubble surfactometer. With meconium, almost all surface activity measures were improved by the addition of HA of several molecular weights at a concentration of 0.25%. Anesthetized, paralyzed rats were maintained on positive-pressure ventilation. After lung injury by instillation of meconium, they were treated with Survanta, Survanta with HA, or control mixtures. Serial measures of blood gases and peak inspiratory pressure were recorded for the duration of the experiment. When the Survanta plus HA group was compared with the Survanta alone group, arterial oxygen tension averaged 117% higher, peak inspiratory pressure was 27% lower at the end of the experiment, and lung compliance also showed significant improvement. These results indicate that HA added to Survanta decreases inactivation caused by meconium in vitro and improves gas exchange and pulmonary mechanics of animals with meconiuminduced acute lung injury. Abbreviations HA, hyaluronan (hyaluronic acid) PEG, polyethylene glycol PIP, peak inspiratory pressure PV, pressure-volume SA, surface area ⌬A 10 , percentage decrease in surface area from the maximum to reach a surface tension of 10 mN/m Hyaluronan (HA) is an ionic polymer of alternating Nacetylglucosamine and glucuronate units. It is one of the glycosaminoglycans that includes chondroitin, keratan, and heparan sulfates. Although HA has a simple chemical structure, it can assume a large number of conformations in aqueous solutions. These conformations allow HA to play many roles in biologic systems, such as being a space filler in the vitreous humor and serving as a viscoelastic substance in joints. In addition, HA interacts with cell surface receptors such as the receptor to HA-mediated motality RHAMM and CD44 (1-3). The biocompatibility of HA has led to many applications, including viscosurgery to allow the creation of space between tissues (4) and lubrication of arthritic joints.The role of HA in a variety of respiratory diseases has also been investigated by several groups. found that HA binds to elastic fibers, preventing elastolysis and limiting airspace enlargement in experimental models of emphysema induced by elastases. Forteza et al. (8) proposed that HA plays a major role in mucosal host defense by stimulating ciliary beating via the RHAMM. Because HA is secreted into the alveolar subphase by type II cells (9,10), it has been suggested that it may interact with lung surfactant (11).Our previous work has shown that adding HA to different lung surfactants improved the surface activity and decreased surfactant inactivation caused by serum (12). In this study, we investigated the effects of using HA Survanta mixtures i...

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“…The thickness of these films is high compared with the monolayered sheet thickness of 0.3 nm formed by evaporation on hydrophilic mica [4], but it is of the order of magnitude of the length of the chain repeating unit (∼1 nm). Depending on the NaHA concentration, the molecules may lie parallel to the interface (low concentration) or orient nearly perpendicular to the interface (high concentration).…”

Section: Disjoining Pressure Isothermsmentioning

confidence: 97%

“…The distance between the branches (jump size) decreases as the NaHA concentration increases and, for each concentration, it is of the order of the correlation length calculated using Eqs. (4) or (5). This behaviour may be ascribed to the stratification of the film where the thickness of the strata corresponds to the correlation length.…”

Section: Disjoining Pressure Isothermsmentioning

confidence: 99%

“…Jacoboni el al. [4] found that on hydrophilic mica HA molecules formed monolayered sheets, 0.3 nm thick, while on hydrophobic graphite the HA molecules form a less ordered network with non-uniform height which does not correspond to a monolayer. Different results were reported by Cowman et al [5] who claim that HA molecules interact more strongly with graphite than with mica.…”

Section: Introductionmentioning

confidence: 97%

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