Safety and feasibility of minimally invasive coronary artery bypass surgery early after drug-eluting stent implantation due to acute coronary syndrome.

BACKGROUND: The evidence on performing minimally invasive coronary artery surgery early after drug-eluting stent (DES) implantation due to acute coronary syndrome (ACS) is limited. AIM: The study aimed to determine the safety and feasibility of this approach. METHODS: This registry included 115 (78% male) patients treated from 2013 to 2018, who underwent non-left anterior descending (LAD) percutaneous coronary intervention (PCI) due to ACS with contemporary DES implantation (39% diagnosed with myocardial infarction at baseline), followed by endoscopic atraumatic coronary artery bypass (EACAB) surgery within 180 days, after temporary P2Y12 inhibitor discontinuation. Primary composite endpoint of MACCE (major adverse cardiac and cerebrovascular events), defined as death, myocardial infarction (MI), cerebrovascular incident, and repeat revascularization was evaluated in long-term follow-up. The follow-up was collected via a telephone survey and in line with National Registry for Cardiac Surgery Procedures. RESULTS: The median (interquartile range [IQR]) time interval separating both procedures was 100.0 (62.0-136.0) days. Median (IQR) follow-up duration was 1338.5 (753.0-2093.0) days and was completed for all patients with regard to mortality. Eight patients (7%) died; 2 (1.7%) had a stroke; 6 (5.2%) suffered from MI, and 12 (10.4%) required repeat revascularization. Overall, the incidence of MACCE was 20 (17.4%). CONCLUSIONS: EACAB is a safe and feasible method of LAD revascularization in patients who received DES for ACS within 180 days before surgery despite early dual antiplatelet therapy discontinuation. The adverse event rate is low and acceptable.

One-stage hybrid coronary revascularization for the treatment of multivessel coronary artery disease- Periprocedural and long-term results from the "HYBRID-COR" feasibility study.

Background: The constant growth of interest in hybrid coronary artery revascularization (HCR) is apparent. Yet, few studies report outcomes of the one-stage HCR. Consequently, the status of such procedures is not adequately supported in clinical guidelines. The aim of this study was to report the safety, feasibility, and long term-outcomes of the one-stage HCR. Methods and results: Patients were enrolled in the prospective one-stage hybrid coronary revascularization program (HYBRID-COR). They underwent a one-stage hybrid revascularization procedure while on double antiplatelet therapy (DAPT) with Ticagrelor: endoscopic atraumatic coronary artery bypass grafting (EACAB) for revascularization of the left anterior descending (LAD) artery and percutaneous intervention in non-LAD arteries with contemporary drug-eluting stents. The composite primary endpoint included MACCE (major adverse cardiac and cerebrovascular events: death, myocardial infarction, stroke, and repeated revascularization) in long-term observation. The study cohort consisted of 30 patients (68% male) with stable coronary artery disease (26.7%) and unstable angina (73.3%). Procedural success was 100%. No death, myocardial infarction (MI), or stroke were observed in the perioperative period. One patient (3.3%) required chest revision and blood transfusion due to surgical bleeding. Kidney injury was noted in two patients (6.6%). In a long-term follow-up (median; IQR: 4.25; 2.62-4.69 years), two patients (6.6%) underwent repeated revascularization and one patient (3.3%) died due to MI. The overall primary endpoint rate was 9.9%. Conclusion: One-stage hybrid revascularization, on DAPT, is a feasible, safe, and efficient way of achieving complete revascularization in selected patients. The complication rate is low and acceptable. Further randomized trials are required.

A Review of the Health Benefits of Food Enriched with Kynurenic Acid.

Kynurenic acid (KYNA), a metabolite of tryptophan, is an endogenous substance produced intracellularly by various human cells. In addition, KYNA can be synthesized by the gut microbiome and delivered in food. However, its content in food is very low and the total alimentary supply with food accounts for only 1-3% of daily KYNA excretion. The only known exception is chestnut honey, which has a higher KYNA content than other foods by at least two orders of magnitude. KYNA is readily absorbed from the gastrointestinal tract; it is not metabolized and is excreted mainly in urine. It possesses well-defined molecular targets, which allows the study and elucidation of KYNA's role in various pathological conditions. Following a period of fascination with KYNA's importance for the central nervous system, research into its role in the peripheral system has been expanding rapidly in recent years, bringing some exciting discoveries. KYNA does not penetrate from the peripheral circulation into the brain; hence, the following review summarizes knowledge on the peripheral consequences of KYNA administration, presents data on KYNA content in food products, in the context of its daily supply in diets, and systematizes the available pharmacokinetic data. Finally, it provides an analysis of the rationale behind enriching foods with KYNA for health-promoting effects.

Tryptophan as a Safe Compound in Topical Ophthalmic Medications: In Vitro and In Vivo Studies.

BACKGROUND: To evaluate the effects of tryptophan (TRP) on normal human corneal and conjunctival epithelium in vitro and the re-epithelization of corneal erosion in rabbits. MATERIALS AND METHODS: Corneal epithelial cell (10.014 pRSV-T) and conjunctival epithelial cell (HC0597) cultures were used. The cellular metabolism, viability, secretion of IL-1ß, IL-6, IL-10, cytoskeleton organization, transwell migration were determined. Cells were incubated in the presence of TRP at 1-100 µM. After corneal de-epithelization rabbits received TRP drops (100 µM), 5 times a day. RESULTS: TRP increased conjunctival epithelium metabolism at 50 µM and increased the viability of corneal epithelium at 100 µM. TRP (10 µM) enhanced the production of IL-6 by the corneal epithelium and had no effect on IL-1ß and IL-10. CONCLUSIONS: TRP had no influence on the cellular cytoskeleton but induced a significant pseudopodia projection in both epithelia. TRP did not influence corneal re-epithelization in vivo. TRP was not toxic for corneal and conjunctival epithelia.

Spectacular Effect of Massive Facial Angiofibromas Removal With a Carbon Dioxide Laser as a Manifestation of a Tuberous Sclerosis Complex.

Introduction: Tuberous sclerosis complex (TSC) is a rare, genetic disease which leads to neurological, cardiological, nephrological, ophthalmic, pulmonary and skin disorders. Case Presentation: Here, we describe a case of a 64-year-old man with the presence of giant angiofibromas located on his chin and nasolabial folds which caused inconvenience and unaesthetic appearance. All angiofibromas were removed with the use of a CO2 laser. The patient was extremely satisfied with the obtained result. No side effects were observed after a 6-month follow-up. Conclusion: Despite the fact that giant facial angiofibromas may be troublesome not only for patients but also for medical doctors, adequate CO2 laser usage with local anesthesia and control of massive bleeding is a promising treatment option for patients with TSC.

Kynurenic Acid Accelerates Healing of Corneal Epithelium In Vitro and In Vivo.

Kynurenic acid (KYNA) is an endogenous compound with a multidirectional effect. It possesses antiapoptotic, anti-inflammatory, and antioxidative properties that may be beneficial in the treatment of corneal injuries. Moreover, KYNA has been used successfully to improve the healing outcome of skin wounds. The aim of the present study is to evaluate the effects of KYNA on corneal and conjunctival cells in vitro and the re-epithelization of corneal erosion in rabbits in vivo. Normal human corneal epithelial cell (10.014 pRSV-T) and conjunctival epithelial cell (HC0597) lines were used. Cellular metabolism, cell viability, transwell migration, and the secretion of IL-1ß, IL-6, and IL-10 were determined. In rabbits, after corneal de-epithelization, eye drops containing 0.002% and 1% KYNA were applied five times a day until full recovery. KYNA decreased metabolism but did not affect the proliferation of the corneal epithelium. It decreased both the metabolism and proliferation of conjunctival epithelium. KYNA enhanced the migration of corneal but not conjunctival epithelial cells. KYNA reduced the secretion of IL-1ß and IL-6 from the corneal epithelium, leaving IL-10 secretion unaffected. The release of all studied cytokines from the conjunctival epithelium exposed to KYNA was unchanged. KYNA at higher concentration accelerated the healing of the corneal epithelium. These favorable properties of KYNA suggest that KYNA containing topical pharmaceutical products can be used in the treatment of ocular surface diseases.

Effect of 4-week physical exercises on tryptophan, kynurenine and kynurenic acid content in human sweat.

The aim of the study was the detection of TRP, kynurenine (KYN), and kynurenic acid (KYNA) in human sweat, and determining whether physical activity affects their content in this secrete. Two different methods were used simultaneously-collection of sweat by means of an absorption pad from the inter scapular region, and collection of a drop of sweat from the region of the forehead. Quantitative determinations of TRP, KYN and KYNA were performed using high performance liquid chromatography with ultraviolet and fluorescence detection. Determinations of sodium was carried out by the method of inductively coupled plasma collision/reaction cell ionization mass spectrophotometry. It was found that physical exercises evoked a decrease in the amount of KYN, and an increase in the amount of KYNA in sweat recorded on day 14, but not on day 28 of training. It appears that physical exercises result in a long-term increase in the kynurenine transaminase activity responsible for the formation of KYNA from KYN. Based on this results, it can be suggested that measurement of TRP, KYN and KYNA in sweat may have diagnostic potential and may help to establish an exercise regime appropriate for the age, gender and health status of rehabilitation patients.

Novel hematological biomarkers predict survival in renal cell carcinoma patients treated with nephrectomy.

INTRODUCTION: The association between novel blood-based inflammatory indices and patient survival has been reported with reference to various cancers. The aim of this study was to investigate the prognostic value of preoperative platelet-lymphocyte ratio (PLR), neutrophil-lymphocyte ratio (NLR), derived neutrophil-lymphocyte ratio (dNLR) and lymphocyte-monocyte ratio (LMR) in patients with renal cell carcinoma (RCC) treated with nephrectomy. MATERIAL AND METHODS: From 2003 to 2012, 455 patients who underwent partial or radical nephrectomy for RCC were enrolled in the study. The study endpoints were overall survival (OS) and cancer-specific survival (CSS). RESULTS: The median follow-up was 70 months. Groups of patients with high levels of PLR, NLR and dNLR and a low level of LMR more often underwent radical nephrectomy, had a higher cancer stage in the TNM classification, and were more frequently diagnosed with tumor necrosis in histopathological examination. Both cancer-specific mortality and overall mortality were significantly higher in patients with high PLR, NLR and dNLR and low LMR. Multivariate analysis of CSS, adjusted for standard clinicopathological factors, identified only dNLR (p = 0.006) as an independent prognostic factor. PLR (p = 0.0002), dNLR (p = 0.0003) and NLR (p = 0.002), but not LMR (p = 0.1), achieved prognostic significance in multivariable analysis regarding OS. CONCLUSIONS: Only dNLR was an independent prognostic factor for CSS and OS. Nevertheless, our study indicates that all examined complete blood count-based biomarkers may be useful tools in managing RCC patients treated with a surgical approach.

Neutrophil-to-mean platelet volume ratio as a new predictor for overall and cancer-specific survival in patients with localized clear cell renal cell carcinoma.

INTRODUCTION: The present study investigated the prognostic value of neutrophil-to-mean platelet volume ratio (NMPVR) for overall (OS) and cancer-specific survival (CSS) in patients treated with nephrectomy for localized clear cell renal cell carcinoma (ccRCC). MATERIAL AND METHODS: Medical records of 344 consecutive patients who underwent partial or radical nephrectomy for M0 ccRCC were retrospectively analyzed. Based on the median NMPVR, the study population was divided into two groups: the high NMPVR group with NMPVR higher than or equal to the median, and the low NMPVR group with NMPVR lower than the median. Comparisons of baseline characteristics and laboratory and pathological findings were performed. Kaplan-Meier survival curves and Cox regression model analysis were used to assess the prognostic value of the NMPVR. RESULTS: Patients with higher NMPVR values were more frequently diagnosed with advanced disease, tumor necrosis and higher tumor grade. The OS and CSS were significantly shorter in patients with NMPVR ≥ 0.41 compared to patients with NMPVR < 0.41. Inclusion of NMPVR in multivariable models of OS and CSS with other confounding variables determined categorized NMPVR as an independent prognostic factor for both endpoints. CONCLUSIONS: Pretreatment NMPVR ≥ 0.41 was associated with lower OS and CSS. NMPVR might be applied as a cheap and uncomplicated prognostic indicator in localized ccRCC patients treated with a primary surgical approach.

Use of laser therapy in the treatment of severe rhinophyma: a report of two cases.

Rhinophyma is a rare manifestation of rosacea. It is clinically characterized by sebaceous hypertrophy, fibrosis, and telangiectasia. Usually, it is considered as a cosmetic defect; however, in some cases, it might cause problems with nasal breathing and food consumption which forces the need for treatment. The following article presents the effectiveness of laser treatment with the neodymium-yttrium-aluminum garnet (Nd:YAG), carbon dioxide laser (CO2), and fractional CO2 laser.

Examination of Kynurenine Toxicity on Corneal and Conjunctival Epithelium: In vitro and in vivo Studies.

Kynurenine (KYN) is a metabolite of tryptophan, proposed for the treatment of corneal diseases. Our goal was to evaluate the effects of KYN on normal human corneal and conjunctival epithelial cells in vitro and the re-epithelization of corneal erosion in rabbits. In our study, we used corneal (10.014 pRSV-T) and conjunctival (HC0597) epithelium cell cultures. KYN was applied at a concentration range of 1-100 µM for 24 and 48 h. We examined the effects on cellular metabolism, viability, interleukin-1ß (IL-1ß), IL-6, IL-10 secretion, cytoskeleton organization and transwell migration ability. Following a bilateral corneal de-epithelialization, the rabbits received drops containing 1% KYN and a saline solution to the contralateral control eye, 5 times daily. Digital images were analyzed using the EPCO 2000 software. The metabolic activity of cells was slightly decreased by KYN in the corneal but not in the conjunctival epithelium. The viability of both epithelia was improved by KYN; it caused alterations in the secretion of IL-6 and IL-10 but not IL-1ß. It had no impact on both epithelia morphology and the organization of the cellular cytoskeleton. KYN stimulated the formation of pseudopodia projections in both epithelia in vitro, which may be important in terms of wound healing. However, there were no differences in the re-epithelization rate in vivo. At the tested concentrations, KYN was not toxic for the corneal and the conjunctival epithelium in vitro and did not affect corneal re-epithelization in rabbits in vivo. Our results suggest that KYN may be taken into consideration for the treatment of ocular disorders.

Kynurenic acid as the neglected ingredient of commercial baby formulas.

The global increase in resorting to artificial nutritional formulas replacing breastfeeding has been identified among the complex causes of the obesity epidemic in infants and children. One of the factors recently recognized to influence metabolism and weight gain is kynurenic acid (KYNA), an agonist of G protein-coupled receptor (GPR35). Therefore the aim of the study was to determine the concentration of KYNA in artificial nutritional formulas in comparison with its level in human breast milk and to evaluate developmental changes in rats exposed to KYNA enriched diet during the time of breastfeeding. KYNA levels were measured in milk samples from 25 heathy breast-feeding women during the first six months after labor and were compared with 21 time-adjusted nutritional formulas. Animal experiments were performed on male Wistar rats. KYNA was administered in drinking water. The content of KYNA in human milk increases more than 13 times during the time of breastfeeding while its level is significantly lower in artificial formulas. KYNA was detected in breast milk of rats and it was found that the supplementation of rat maternal diet with KYNA in drinking water results in its increase in maternal milk. By means of the immunoblotting technique, GPR35 was evidenced in the mucosa of the jejunum of 1-day-old rats and distinct morphological changes in the jejunum of 21-day-old rats fed by mothers exposed to water supplemented with KYNA were found. A significant reduction of body weight gain of rats postnatally exposed to KYNA supplementation without changes in total body surface and bone mineral density was observed. The rat offspring fed with breast milk with artificially enhanced KYNA content demonstrated a lower mass gain during the first 21 days of life, which indicates that KYNA may act as an anti-obesogen. Further studies are, therefore, warranted to investigate the mechanisms regulating KYNA secretion via breast milk, as well as the influence of breast milk KYNA on mass gain. In the context of lifelong obesity observed worldwide in children fed artificially, our results imply that insufficient amount of KYNA in baby formulas could be considered as one of the factors associated with increased mass gain.

Presence of kynurenic acid in alcoholic beverages - Is this good news, or bad news?

Kynurenic acid (KYNA) is a metabolite of tryptophan formed enzymatically along kynurenine pathway in bacteria, fungi, plants and animals. It was suggested that yeast may produce KYNA during the fermentation process. Since KYNA was found to interact with alcohol metabolism by inhibition of aldehyde dehydrogenase activity the aim of this study was to measure the content of KYNA in selected alcoholic beverages of various type, beer, wine, mead and spirits. Moreover, the absorption and elimination rate of KYNA administered as a beverage was investigated in humans. Twelve healthy volunteers (6 female and 6 male) were studied. Fifty six samples of alcoholic beverages were of commercial origin. KYNA was determined by means of high-performance liquid chromatography method with fluorometric detection. KYNA was identified in all studied beverages. The amounts of KYNA found in various types of beverages differed significantly: mead 9.4-38.1 µg/100 ml, wine 1.4-10.9 µg/100 ml, beer 0.1-5.2 µg/100 ml, spirits 0.01-0.1 µg/100 ml. In human, it was found that KYNA is rapidly absorbed from digestive tract reaching its maximal concentration in blood 30 min after administration. Thus, the potential interaction between KYNA and alcohol occurring in human body after ingestion of alcoholic beverages was proven.

Fate and distribution of kynurenic acid administered as beverage.

BACKGROUND: Kynurenic acid (KYNA) is a biologically active metabolite of tryptophan exerting action on several receptors located in the brain and periphery. KYNA can be synthesized endogenously or supplied in the diet. It was documented that KYNA is present in various types of food. However, its presence in beverages was not yet investigated. Here, we measured content of KYNA in tea and coffee as well as analyzed distribution and fate of intragastrically administered labelled KYNA in mice. METHODS: 16 and 13 studied samples of tea and coffee, respectively were of commercial origin. Tea and coffee infusions were prepared according to the producers' guidelines. KYNA content in beverages was measured by means of HPLC detection. Adult male mice were used for analysis of fate of intragastrically administered labelled KYNA and collected samples were analyzed using liquid scintillation counter. RESULTS: KYNA was identified in all studied beverages. Amounts of KYNA found in various types of beverages differed significantly. The highest content of KYNA in tea and coffee was 8.7 µg/100 ml and 0.63 µg/100 ml, respectively. It was found that KYNA administered intragastrically as a liquid is absorbed from the digestive system and readily excreted in urine. The atypical kinetics of KYNA distribution were found in intestinal content of cecum, where it appeared later and persisted longer than in other tissues. CONCLUSIONS: Our data show that tea and coffee intake may contribute to KYNA content in the human organism. The distribution pattern of KYNA delivered as a liquid suggests that it either directly affects digestive system's functioning and intestinal microbiome composition, or participates in the whole body pool of KYNA.

[The changing face of medium-sized vasculitis].

Polyarteritis nodosa is a systemic necrotizing vasculitis which predominantly affects medium-sized arteries. It is a rare disease nowadays. Both the nomenclature and the classification of polyarteritis nodosa was amended several times in the past. Currently, there is a distinction between the primary form described as classical polyarteritis nodosa and other forms that are associated with their probable cause e.g. with viral hepatitis B, C or HIV infection. Moreover, polyarteritis-like necrotizing vasculitis can appear in the course of genetic diseases caused by mutations in single genes. The pathogenesis of idiopathic polyarteritis nodosa is still unclear, but a dominant role of the adaptive immune system disorders is suggested. Interestingly, in the hepatitis B virus-related vasculitis development, immune complexes are believed to play a crucial role. The spectrum of clinical manifestations of polyarteritis nodosa is wide, from involving a single organ to the polyvisceral failure. In the course of polyarteritis nodosa nearly each organ can be involved, however the disease never affects the lungs. Special forms of polyarteritis nodosa include a single-organ disease and a cutaneous form. The diagnosis of polyarteritis nodosa requires integration of clinical, angiographic and biopsy findings. Recognizing the form of polyarteritis nodosa, determining affected organs and the progression of the disease is very important since those are deciding factors when choosing treatment strategies.

[Cutaneous polyarteritis nodosa].

Cutaneous polyarteritis nodosa is a rare disease that affects vessels of the deep skin and the subcutaneous tissue. Its etiopathology remains unknown. It predominantly affects skin, and the main cutaneous symptoms are subcutaneous nodules, livedo reticularis, and ulcerations that are mainly located on legs. Cutaneous polyarteritis nodosa can also cause extracutaneous symptoms (fever, malaise, myalgias, arthralgias, neuropathy). It is a chronic benign disease with a relapsing course. Diagnostic criteria for this disease were recently proposed and both clinical and typical histological features must be present to confirm the diagnosis. Treatment of cutaneous polyarteritis nodosa depends on the severity of the disease and the frequency of relapses. Mild forms limited to skin lesions should be treated with nonsteroidal anti-inflammatory drugs, colchicine and locally applied glucocorticosteroids. Cases that are refractory to the treatment, that recur with extracutaneous symptoms may require applying more aggressive approach (glucocorticosteroids orally, hydroxychloroquine, azathioprine, methotrexate, mycophenolate mofetil or intravenous immunoglobulins). The prognosis in cutaneous polyarteritis nodosa is favorable and the disease rarely turns into a systemic form.

Kynurenic acid content in anti-rheumatic herbs.

INTRODUCTION: The use of herbal medicines is common among people living in rural areas and increasingly popular in urbanized countries. Kynurenic acid (KYNA) is a metabolite of kynurenine possessing anti-inflammatory, anti-oxidative and pain reliving properties. Previous data indicated that the content of KYNA in the synovial fluid of patients with rheumatoid arthritis is lower than in patients with osteoarthritis. Rheumatoid arthritis is a chronic, systemic inflammatory disorder affecting about 1% of the world's population. AIM: The aim of the presented study was to investigate the content of KYNA in 11 herbal preparations used in rheumatic diseases. MATERIALS AND METHODS: The following herbs were studied: bean pericarp, birch leaf, dandelion root, elder flower, horsetail herb, nettle leaf, peppermint leaf and willow bark. An anti-rheumatic mixture of the herbs Reumatefix and Reumaflos tea were also investigated. The herbs were prepared according to producers' directions. In addition, the herbal supplement Devil's Claw containing root of Harpagophytum was used. KYNA content was measured using the high-performance liquid chromatography method, and KYNA was detected fluorometrically. RESULTS: KYNA was found in all studied herbal preparations. The highest content of KYNA was found in peppermint, nettle, birch leaf and the horsetail herb. The lowest content of KYNA was found in willow bark, dandelion root and in the extract from the root of Harpagophytum. CONCLUSION: These findings indicate that the use of herbal preparations containing a high level of KYNA can be considered as a supplementary measure in rheumatoid arthritis therapy, as well as in rheumatic diseases prevention.

Kynurenic Acid in the digestive system-new facts, new challenges.

This review provides information on the most recent findings concerning presence, origin, and role of kynurenic acid (KYNA), a tryptophan metabolite, in the digestive system. KYNA is an antagonist of both the ionotropic glutamate receptors and the alpha7 nicotinic acetylcholine receptor, as well as an agonist of G-protein coupled GPR35 receptor. Since the GPR35 receptor is mainly present in the gastrointestinal tract, researchers have concentrated on the digestive system in recent years. They have found that KYNA content increases gradually and significantly along the gastrointestinal tract. Interestingly, the concentration of KYNA in the lumen is much higher than in the wall of intestine. It has been documented that KYNA may have a positive influence on the number of pathologies in the gastrointestinal tract, in particular ulcers, colon obstruction, or colitis. Future studies might determine whether it is advisable to supplement KYNA to a human organism.

Potato- an important source of nutritional kynurenic acid.

Kynurenic acid (KYNA) is a metabolite of tryptophan which is formed along the kynurenine pathway. KYNA may possess neuroprotective, anti-inflammatory, antioxidant and antiproliferative properties. This study measured the concentration of KYNA in various varieties of potatoes and products made from potatoes. KYNA content was determined by means of the high-performance liquid chromatography with fluorescence detection. KYNA was found in all 16 studied varieties of potato tubers in amounts varying from 0.239 to 3.240 µg/g dry weight. The content of KYNA in potato tubers declined during long-term storage. The content of KYNA in French fries varied from 0.100 to 0.646 µg/g dry weight. KYNA content in potato crisps was 0.478 and 0.576 µg/g dry weight. Hence, all in all, we concluded that the amount of KYNA potentially delivered to the human body in potatoes and various foods produced from potatoes is high and might be compared to the amount of KYNA present in a maximum daily dose of popular herbs and herbal medicines.

Distribution, synthesis, and absorption of kynurenic acid in plants.

Kynurenic acid (KYNA) is an endogenous antagonist of the ionotropic glutamate receptors and the α7 nicotinic acetylcholine receptor as well as an agonist of the G-protein-coupled receptor GPR35. In this study, KYNA distribution and synthesis in plants as well as its absorption was researched. KYNA level was determined by means of the high-performance liquid chromatography with fluorescence detection. KYNA was found in leaves, flowers, and roots of tested medicinal herbs: dandelion (Taraxacum officinale), common nettle (Urtica dioica), and greater celandine (Chelidoniummajus). The highest concentration of this compound was detected in leaves of dandelion--a mean value of 0.49 µg/g wet weight. It was shown that KYNA can be synthesized enzymatically in plants from its precursor, L-kynurenine, or absorbed by plants from the soil. Finally, the content of KYNA was investigated in 21 herbal tablets, herbal tea, herbs in sachets, and single herbs in bags. The highest content of KYNA in a maximum daily dose of herbal medicines appeared in St. John's wort--33.75 µg (tablets) or 32.60 µg (sachets). The pharmacological properties of KYNA and its presence in high concentrations in medicinal herbs may suggest that it possesses therapeutic potential, especially in the digestive system and should be considered a new valuable dietary supplement.