The skin, acting as the outer protection of the human body, is most vulnerable to injury. Wound healing can often be impaired, leading to chronic, hard-to-heal wounds. For this reason, searching for the most effective dressings that can significantly enhance the wound healing process is necessary. In this regard, silk fibroin, a protein derived from silk fibres that has excellent properties, is noteworthy. Silk fibroin is highly biocompatible and biodegradable. It can easily make various dressings, which can be loaded with additional substances to improve healing. Dressings based on silk fibroin have anti-inflammatory, pro-angiogenic properties and significantly accelerate skin wound healing, even compared to commercially available wound dressings. Animal studies confirm the beneficial influence of silk fibroin in wound healing. Clinical research focusing on fibroin dressings is also promising. These properties make silk fibroin a remarkable natural material for creating innovative, simple, and effective dressings for skin wound healing. In this review, we summarise the application of silk fibroin biomaterials as wound dressings in full-thickness, burn, and diabetic wounds in preclinical and clinical settings.

Impaired wound healing affects hundreds of million people around the world; therefore, chronic wounds are a major problem not only for the patient, but also for already overloaded healthcare systems. Chronic wounds are always very susceptible to infections. Billions of dollars are spent to discover new antibiotics as quickly as possible; however, bacterial resistance against antibiotics is rising even faster. For this reason, a complete shift of the antibacterial treatment paradigm is necessary. The development of technology has allowed us to rediscover well-known agents presenting antimicrobial properties with a better outcome. In this context, silver nanoparticles are a promising candidate for use in such therapy. Silver has many useful properties that can be used in the treatment of chronic wounds, such as anti-bacterial, anti-inflammatory, and anti-oxidative properties. In the form of nanoparticles, silver agents can work even more effectively and can be more easily incorporated into various dressings. Silver-based dressings are already commercially available; however, innovative combinations are still being discovered and very promising results have been described. In this review article, the authors focused on describing experimental and clinical studies exploring dressings containing either silver or silver nanoparticles, the results of which have been published in recent years.

Resistance to antimicrobial agents by pathogenic bacteria has emerged in recent years and is a major health problem. In this context silver and silver nanoparticles (AgNP) have been known to have inhibitory and bactericidal effects and was used throughout history for treatment of skin ulcer, bone fracture, and supporting wound healing. In all of these applications prevention and treatment of bacterial colonized/infected wounds are critical. In this context silver and its derivatives play an important role in health care. Silver is widely used in clinical practice in the form of silver nitrate and/or silver sulfadiazine. In the last few years silver nanoparticles entered into clinical practice as both antimicrobial and antifungal agents. In addition, nanosilver is used in coating medical devices (catheters) and as component of wound dressings. In this paper we present summarized information about silver and nanoparticles made of silver in the context of their useful properties, especially antibacterial ones, being of a great interest for researchers and clinicians.

Several studies have suggested negative effects of trimethylamine oxide (TMAO) on the circulatory system. However, a number of studies have shown protective functions of TMAO, a piezolyte and osmolyte, in animals exposed to high hydrostatic and/or osmotic stress. We evaluated the effects of TMAO treatment on the development of hypertension and its complications in male spontaneously hypertensive rats (SHRs) maintained on water (SHR-Water) and SHRs drinking TMAO water solution from weaning (SHR-TMAO). Wistar-Kyoto (WKY) rats were used as normotensive controls to discriminate between age-dependent and hypertension-dependent changes. Telemetry measurements of blood pressure were performed in rats between the 7th and 16th weeks of life. Anesthetized rats underwent echocardiographic, electrocardiographic, and direct left ventricular end-diastolic pressure (LVEDP) measurements. Hematoxylin and eosin as well as van Gieson staining for histopathological evaluation were performed. Plasma TMAO measured by chromatography coupled with mass spectrometry was significantly higher in the SHR-Water group compared with the WKY group (~20%). TMAO treatment increased plasma TMAO by four- to fivefold and did not affect the development of hypertension in SHRs. Sixteen-week-old rats in the SHR-Water and SHR-TMAO groups (12-wk TMAO treatment) showed similar blood pressures, angiopathy, and cardiac hypertrophy. However, the SHR-TMAO group had lower plasma NH₂-terminal pro-B-type natriuretic peptide, LVEDP, and cardiac fibrosis. In contrast to age-matched WKY rats, 60-wk-old SHRs showed hypertensive angiopathy and heart failure with preserved ejection fraction. Compared with the SHR-Water group, the SHR-TMAO group (56-wk TMAO treatment) showed significantly lower plasma NH₂-terminal pro-B-type natriuretic peptide and vasopressin, significantly lower LVEDP, and cardiac fibrosis. In conclusion, a four- to fivefold increase in plasma TMAO does not exert negative effects on the circulatory system. In contrast, increased dietary TMAO seems to reduce diastolic dysfunction in pressure-overloaded hearts in rats.NEW & NOTEWORTHY Chronic, low-dose trimethylamine oxide (TMAO) treatment that increases plasma TMAO by four- to fivefold reduces plasma NH₂-terminal pro-B-type natriuretic peptide and vasopressin, left ventricular end-diastolic pressure, and cardiac fibrosis in pressure-overloaded hearts in hypertensive rats. Our study provides evidence that a moderate increase in plasma TMAO does not have a negative effect on the circulatory system. In contrast, increased dietary TMAO seems to reduce diastolic dysfunction in the pressure-overloaded heart.

Impaired wound healing is a major medical problem. To solve it, researchers around the world have turned their attention to the use of tissue-engineered products to aid in skin regeneration in case of acute and chronic wounds. One of the primary goals of tissue engineering and regenerative medicine is to develop a matrix or scaffold system that mimics the structure and function of native tissue. Keratin biomaterials derived from wool, hair, and bristle have been the subjects of active research in the context of tissue regeneration for over a decade. Keratin derivatives, which can be either soluble or insoluble, are utilized as wound dressings since keratins are dynamically up-regulated and needed in skin wound healing. Tissue biocompatibility, biodegradability, mechanical durability, and natural abundance are only a few of the keratin biomaterials’ properties, making them excellent wound dressing materials to treat acute and chronic wounds. Several experimental and pre-clinical studies described the beneficial effects of the keratin-based wound dressing in faster wound healing. This review focuses exclusively on the biomedical application of a different type of keratin biomaterials as a wound dressing in pre-clinical and clinical conditions.

Recent evidence suggests that tryptophan, an essential amino acid, may exert biological effects by means of tryptophan-derived gut bacteria products. We evaluated the potential contribution of tryptophan-derived bacterial metabolites to body weight gain. The study comprised three experimental series performed on separate groups of male, Sprague-Dawley rats: (i) rats on standard laboratory diet treated with water solution of neomycin, an antibiotic, or tap water (controls-1); (ii) rats on standard diet (controls-2) or tryptophan-high (TH) or tryptophan-free (TF) diet; and (iii) rats treated with indole-3-propionic acid (I3P), a bacterial metabolite of tryptophan, or a vehicle (controls-3). (i) Rats treated with neomycin showed a significantly higher weight gain but lower stool and blood concentration of I3P than controls-1. (ii) The TH group showed significantly smaller increases in body weight but higher stool and plasma concentration of I3P than controls-2. In contrast, the TF group showed a decrease in body weight, decreased total serum protein and a significant increase in urine output. (iii) Rats treated with I3P showed significantly smaller weight gain than controls-3. Our study suggests that I3P, a gut bacteria metabolite of tryptophan, contributes to changes in body weight gain produced by antibiotics and tryptophan-rich diet.