Special section guest editorial: advances in terahertz biomedical science and applications

The Journal of Biomedical Optics (JBO) has published this special section of papers to capture the most recent advances in THz technology and innovative THz instruments and methods in biology and medicine. A few of the papers in this special section are dedicated to similar biomedical applications of novel optical tools from the neighboring infrared (IR) range. Two papers of the special section consider modern problems of oncodiagnosis. In the research article ‘Development of oral cancer tissue-mimicking phantom based on polyvinyl chloride plastisol and graphite for terahertz frequencies’, authors have introduced a new type of a water-free tissue-mimicking phantom for THz biophotonics. This phantom is based on graphite powders embedded into a polyvinyl chloride plastisol matrix. The effective THz optical properties of such a phantom can be managed in a wide range by changing its composition, thus allowing to mimic the THz optical properties of various biological tissues

The relationship of obesity and prostate cancer (review)

Obesity is a critical risk factor for prostate cancer (PCa). Adipose tissue plays an important role in tumor development, including growth, invasion, and metastasis. Diet and dietary components affect the progression of prostate cancer; however, the mechanisms underlying these associations remain unclear. Extraprostatic prostate tumor cells form a new microenvironment in the periprostatic adipose tissue, which alters these interactions and promotes tumor progression. Hyperinsulinemia leads to an increase in the level of free or biologically active insulin-like growth factor (IGF-1) due to a decrease in the production of IGF-binding proteins. Hypoandrogenism promotes the development of a more aggressive type of prostate cancer (higher Gleason scores). Adipokines of adipose tissue and cytokines (for example, interleukin-6 (IL-6) and tumor necrosis factor (TNF-α), angiogenic factors (for example, vascular endothelial growth factor (VEGF), apelin (AGTRL1) and other factors (for example, leptin and adiponectin) have multiple effects on prostate cancer cells. Tumor cells interact directly or indirectly with adipocytes. Yellow (inactive) bone marrow is adipose tissue with separate islands of reticular tissue. It is located in the medullary canals of the tubular bones and in parts of the cells of the cancellous bone. Bone tissue is the object of the most frequent metastasis in prostate cancer, and with age, the content of fat cells in it increases. Bone marrow adipose tissue interacts with tumor cells, osteoblasts and other stromal cells and participates in the organization of the tumor microenvironment. Adipokines are key molecules in the interaction between tumor cells and adipose tissue, which is carried out through various mechanisms. A better understanding of the role of adipose tissue in the induction and progression of prostate cancer will lead to effective therapeutic strategies for this disease

Relationship between prostate cancer and type 2 diabetes mellitus

Type 2 diabetes mellitus (DM2) and prostate cancer are widespread diseases throughout the world. Type II diabetes mellitus is accompanied by a deterioration in glycemic control, hyperinsulinemia, and insulin resistance (IR). The accumulation of glucose and lipids leads to a decrease in the density of insulin receptors and the development of insulin resistance in adipose tissue. This contributes to the development of hyperinsulinemia, which suppresses the breakdown of fat and leads to the progression of obesity. A vicious circle develops: insulin resistance → hyperinsulinemia → obesity → insulin resistance. Insulin influences the progression of the cell cycle, proliferation, and metastatic activity of the tumor.Recent studies have shown a strong direct correlation between fasting insulin levels and cancer mortality in men. This may be especially true in patients over 65, who are, in the first place, more likely to develop prostate cancer than younger patients. It should be noted that it is insulin, and not glucose, that is associated with the claim for the development of cancer. Hyperinsulinemia, which often occurs as a result of androgen deprivation therapy (ADT), the standard treatment for prostate cancer, is associated with a high tumor aggressiveness and faster treatment failure — the development of castrate-refractory prostate cancer. It is reasonable to assume that hyperinsulinemia — under whatever circumstances it is caused, whether due to ADT or due to inadequate nutrition and other lifestyle factors — can have the same negative effect on cellular signaling.Metabolic syndrome — essentially chronically elevated insulin levels — is closely associated with recurrence of cancer and worse post-treatment outcomes, which has led researchers to question generally accepted dietary guidelines for cancer patients, especially when they are undergoing treatment or recover from treatment, which may include recommendations to consume anything that will help maintain or restore body weight, regardless of sugar or carbohydrate content or its effect on insulin levels. A large number of patients live with hyperinsulinemia, but normoglycemia. Chronic hyperinsulinemia is the main driver of cardiometabolic disease, even when blood sugar levels are within reference values. The scale of this problem is not recognized by the medical and scientific community

Metabolic changes in patients with prostate cancer with androgen deprivation therapy

Prostate cancer is the most common type of cancer among men. Androgen deprivation therapy (ADT) is the most effective treatment for this disease. The cornerstone of prostate cancer treatment is the inhibition of testosterone production, which interrupts testosterone-induced growth of the prostate tumour. A sharp decrease in testosterone, however, has several undesirable effects on the metabolic profile and bone metabolism and can also lead to fatigue, loss of libido, gynecomastia and anaemia, provoke vasomotor hyperaemia and generally affect the quality of life. To increase the good (long-term) survival of patients with prostate cancer, studying the side effects associated with treatment is important, and therefore, in every clinical situation, the benefits of ADT must be compared with the side effects associated with the treatment. This article focuses on the described metabolic complications of ADT, including obesity, diabetes, lipid changes, metabolic syndrome and cardiovascular diseases. It also contains practical recommendations for managing the side effects and complications based on the available guidelines issued by the medical professional community

Biomedical applications of sapphire shaped crystals

We have proposed novel medical instrument

In vitro terahertz spectroscopy of malignant brain gliomas embedded in gelatin slab

In our work, we have performed in vitro terahert

Cellular effects of terahertz waves

Significance: An increasing interest in the area of biological effects at exposure of tissues and cells to the terahertz (THz) radiation is driven by a rapid progress in THz biophotonics, observed during the past decades. Despite the attractiveness of THz technology for medical diagnosis and therapy, there is still quite limited knowledge about safe limits of THz exposure. Different modes of THz exposure of tissues and cells, including continuous-wave versus pulsed radiation, various powers, and number and duration of exposure cycles, ought to be systematically studied. Aim: We provide an overview of recent research results in the area of biological effects at exposure of tissues and cells to THz waves. Approach: We start with a brief overview of general features of the THz-wave–tissue interactions, as well as modern THz emitters, with an emphasis on those that are reliable for studying the biological effects of THz waves. Then, we consider three levels of biological system organization, at which the exposure effects are considered: (i) solutions of biological molecules;(ii) cultures of cells, individual cells, and cell structures; and (iii) entire organs or organisms; special attention is devoted to the cellular level. We distinguish thermal and nonthermal mechanisms of THz-wave–cell interactions and discuss a problem of adequate estimation of the THz biological effects’ specificity. The problem of experimental data reproducibility, caused by rareness of the THz experimental setups and an absence of unitary protocols, is also considered. Results: The summarized data demonstrate the current stage of the research activity and knowledge about the THz exposure on living objects. Conclusions: This review helps the biomedical optics community to summarize up-to-date knowledge in the area of cell exposure to THz radiation, and paves the ways for the development of THz safety standards and THz therapeutic applications

Effect of Metabolic Syndrome in Patients with Prostate Cancer (Review)

The human prostate gland is an endocrine organ in which dysregulation of various hormonal factors plays a key role in the development of non-tissue transformation and leads to the formation of prostate cancer. Existing epidemiological data confirm the role of the components of the metabolic syndrome, namely obesity, hypercholesterolemia, diabetes, and hyperinsulinemia, in the development and/or progression of prostate cancer. Although the exact mechanisms underlying the relationship between metabolic syndrome and prostate cancer remain largely unknown, it has been shown that various "in vitro" and animal experiments with models of the metabolic syndrome contribute to survival, mitogenesis, metastasis, and treatment resistance pathways through various adaptive reactions, such as intracellular steroidogenesis and lipogenesis. Although the exact biopathophysiological mechanisms between metabolic syndrome and prostate cancer have yet to be studied, drugs that target specific components of the metabolic syndrome have also provided evidence for the relationship between metabolic syndrome, its components, and prostate cancer. The appearance of “in vitro” results and molecular genetic research data will bring us closer to using this knowledge to determine specific ways of cancer-specific survival and improve treatment outcomes in patients with this disease

Wavelet-domain de-noising of OCT images of human brain malignant glioma

We have proposed a wavelet-domain de-noising technique for imaging of human brain malignant glioma by optical coherence tomography (OCT). It implies OCT image decomposition using the direct fast wavelet transform, thresholding of the obtained wavelet spectrum and further inverse fast wavelet transform for image reconstruction. By selecting both wavelet basis and thresholding procedure, we have found an optimal wavelet filter, which application improves differentiation of the considered brain tissue classes – i.e. malignant glioma and normal/intact tissue. Namely, it allows reducing the scattering noise in the OCT images and retaining signal decrement for each tissue class. Therefore, the observed results reveals the wavelet-domain de-noising as a prospective tool for improved characterization of biological tissue using the OCT

Differentiation of healthy and malignant brain tissues using terahertz pulsed spectroscopy and optical coherence tomography

Intraoperative diagnosis of brain tumors remains a challenging problem of modern neurosurgery. A complete resection of tumor is the most important factor, determining an efficiency of its treatment, while an incomplete resection, caused by inaccurate detection of tumor margins, increases a probability of the tumor recurrence. The existing methods of the intraoperative neurodiagnosis of tumors are plagued with limited sensitivity and specificity; they remain laborious, time-consuming and/or rather expensive. Therefore, the development of novel methods for the intraoperative diagnosis of gliomas relying on modern instruments of medical imaging is a topical problem of medicine, physics, and engineering. In our research, we studied the ability of dual-modality imaging that combines such methods as optical coherence tomography (OCT) and terahertz (THz) pulsed spectroscopy, for intraoperative diagnosis of brain tumors with a strong emphasize on a human brain gliomas. We performed experimental studies of the frequency-dependent THz dielectric properties and OCT imaging of healthy (intact) and pathological brain tissues ex vivo in order to analyze the prospect for differentiation between tissue classes. The observed results highlight a potential of the considered instruments in the label-free intraoperative neurodiagnostics