Living Cell as a Self-Synchronized Chemical Reactor

Thermal fluctuations power all processes inside living cells. Therefore, these processes are inherently random. However, myriad multistep chemical reactions act in concerto inside a cell, finally leading to this chemical reactor's self-replication. We speculate that an underlying mechanism in nature must exist that allows all of these reactions to synchronize at multiple time and length scales, overcoming in this way the random nature of any single process in a cell. This Perspective discusses what type of research is needed to understand this undiscovered synchronization law.

Quantitative analysis of biochemical processes in living cells at a single-molecule level: a case of olaparib-PARP1 (DNA repair protein) interactions

Quantitative description of biochemical processes inside living cells and at single-molecule levels remains a challenge at the forefront of modern instrumentation and spectroscopy. This paper demonstrates such single-cell, single-molecule analyses performed to study the mechanism of action of olaparib - an up-to-date, FDA-approved drug for germline-BRCA mutated metastatic breast cancer. We characterized complexes formed with PARPi-FL - fluorescent analog of olaparib in vitro and in cancer cells using the advanced fluorescent-based method: Fluorescence Correlation Spectroscopy (FCS) combined with a length-scale dependent cytoplasmic/nucleoplasmic viscosity model. We determined in vitro olaparib-PARP1 equilibrium constant (6.06 × 10⁸ mol L^-1). In the cell nucleus, we distinguished three states of olaparib: freely diffusing drug (24%), olaparib-PARP1 complex (50%), and olaparib-PARP1-RNA complex (26%). We show olaparib accumulation in 3D spheroids, where intracellular concentration is twofold higher than in 2D cells. Moreover, olaparib concentration was tenfold higher (506 nmol L^-1vs. 57 nmol L^-1) in cervical cancer (BRCA1 high abundance) than in breast cancer cells (BRCA1 low abundance) but with a lower toxic effect. Thus we confirmed that the amount of BRCA1 protein in the cells is a better predictor of the therapeutic effect of olaparib than its penetration into cancer tissue. Our single-molecule and single-cell approach give a new perspective of drug action in living cells. FCS provides a detailed in vivo insight, valuable in drug development and targeting.

Two Intercalation Mechanisms of Oxazole Yellow Dimer (YOYO-1) into DNA

The oxazole yellow dye, YOYO-1 (a symmetric homodimer), is a commonly used molecule for staining DNA. We applied the brightness analysis to study the intercalation of YOYO-1 into the DNA. We distinguished two binding modes of the dye to dsDNA: mono-intercalation and bis-intercalation. Bis-intercalation consists of two consecutive mono-intercalation steps, characterised by two distinct equilibrium constants (with the average number of base pair per binding site equals 3.5): K1=3.36±0.43×107M−1 and K2=1.90±0.61×105M−1, respectively. Mono-intercalation dominates at high concentrations of YOYO-1. Bis-intercalation occurs at low concentrations.

Transport of nanoprobes in multicellular spheroids

The efficient delivery of drugs to cells depends on their diffusion through the extracellular matrix (ECM) of tissues. Here we present a study on the diffusion of nanoprobes of radius from 1 nm to over 100 nm in the ECM of spheroids of three cell types (HeLa, MCF-7 and fibroblasts). We quantified the nanoparticle transport in the spheroids' proliferating zone. We determined the size-dependent viscosity of the ECM. We revealed that nanoobjects up to 10 nm in radius exhibited unobstructed diffusion in the ECM, regardless of the spheroid type. The presented length-scale dependent viscosity profiles for spheroids pave the way for advanced modelling of drug administration through tissues.

TMAO, a seafood-derived molecule, produces diuresis and reduces mortality in heart failure rats

Trimethylamine-oxide (TMAO) is present in seafood which is considered to be beneficial for health. Deep-water animals accumulate TMAO to protect proteins, such as lactate dehydrogenase (LDH), against hydrostatic pressure stress (HPS). We hypothesized that TMAO exerts beneficial effects on the circulatory system and protects cardiac LDH exposed to HPS produced by the contracting heart. Male, Sprague-Dawley and Spontaneously-Hypertensive-Heart-Failure (SHHF) rats were treated orally with either water (control) or TMAO. In vitro, LDH with or without TMAO was exposed to HPS and was evaluated using fluorescence correlation spectroscopy. TMAO-treated rats showed higher diuresis and natriuresis, lower arterial pressure and plasma NT-proBNP. Survival in SHHF-control was 66% vs 100% in SHHF-TMAO. In vitro, exposure of LDH to HPS with or without TMAO did not affect protein structure. In conclusion, TMAO reduced mortality in SHHF, which was associated with diuretic, natriuretic and hypotensive effects. HPS and TMAO did not affect LDH protein structure.

Heart failure is a common cause of death in industrialized countries with aging populations. Japan, however, has lower rates of heart failure and fewer deaths linked to this disease than the United States or Europe, despite having the highest proportion of elderly people in the world. Dietary differences between these regions may explain the lower rate of heart failure in Japan. The Japanese diet is rich in seafood, which contains nutrients that promote heart health, such as omega-3 fatty acids.

Seafood also contains other compounds, including trimethylamine oxide (TMAO). Fish that live in deep waters undergo high pressures, which can damage their proteins, but TMAO seems to protect the proteins from harm. In humans, eating seafood increases TMAO levels in the blood and urine, but it is unclear what effects this has on heart health. Increased levels of TMAO in the blood are associated with cardiovascular diseases, but scientists are not sure whether TMAO itself harms the heart. A toxic byproduct of gut bacteria called TMA is converted in TMAO in the body, so it is possible that TMA rather than TMAO is to blame.

To assess the effects of dietary TMAO on heart failure, Gawrys-Kopczynska et al. fed the compound to healthy rats and rats with heart failure for one year. TMAO had no effects on the healthy rats. Of the rats with heart failure that were fed TMAO, all of them survived the year, while one third of rats with heart failure that were not fed TMAO died. TMAO-treated rats with heart failure had lower blood pressure and urinated more than untreated rats with the condition.

The experiments suggest that dietary TMAO may mimic the effects of heart failure treatments, which remove excess water and salt and lower pressure on the heart. More studies are needed to confirm whether TMAO has this same effect on humans.

Abstract P3021: Trimethylamine but Not Trimethylamine N-Oxide Increases Blood Pressure in Rats, Affects Viability of Vascular Smooth Muscle Cells and Degrades Protein Structure

Increased plasma level of trimethylamine N-oxide (TMAO), a liver metabolite of gut bacteria-produced trimethylamine (TMA), has been suggested to increase cardiovascular risk. Mechanisms of TMAO increase in plasma and biological effects of TMAO are obscure. We evaluated the impact of heart failure (HF) on plasma levels of TMA and TMAO, and biological effects of the molecules.

Gut permeability was evaluated in male, 58-week-old Spontaneously Hypertensive Heart Failure (SHHF) and Wistar-Kyoto (WKY) rats. TMA and TMAO levels were assessed using LC-MS. Mean arterial blood pressure (MABP) was measured in anaesthetized, male, 16-week-old WKY treated intravenously with either 0.9% NaCl (vehicle), TMA or TMAO. The cytotoxicity of TMA and TMAO in human vascular smooth muscle cells (hVSMCs) was evaluated using MTT assay. The effect of TMA and TMAO on protein structure of bovine albumin was assessed by fluorescence correlation spectroscopy.

WKY showed no pathological changes in the circulatory system. SHHF showed HF with reduced ejection fraction. In comparison to WKY, SHHF had a significantly higher plasma level (μM) of TMA (99.05±6.40 vs 149.30±21.87) and TMAO (5.22±0.61 vs 6.69±0.67). SHHF had a significantly higher plasma-to-stool ratio of TMA, decreased intestinal blood flow and morphological alterations in the colon indicating the increased gut-to-blood penetration of TMA due to HF-induced leaky gut.

In WKY treatment with the vehicle and TMAO did not affect MABP. In contrast, TMA (at equimolar doses to TMAO) significantly increased MABP by 5-40 mmHg in a dose dependent manner. In vitro, TMA at a concentration of 500μM reduced hVSMCs viability. TMAO at a concentration of 100mM was not cytotoxic whereas TMA at the same concentration killed cells within 24h. Finally, the incubation of albumin with TMA but not with TMAO resulted in the degradation of the protein structure.

In conclusion, HF rats show increased plasma TMA and TMAO, which results from increased gut-to-blood penetration of TMA, a TMAO precursor. TMA but not TMAO affects hemodynamics in rats, reduces viability of cells and degrades protein structure. Therefore, TMA but not TMAO may exert deleterious effects on the circulatory system. Further clinical studies should evaluate not only TMAO but also TMA.

TMA, A Forgotten Uremic Toxin, but Not TMAO, Is Involved in Cardiovascular Pathology

Trimethylamine-N-oxide (TMAO) has been suggested as a marker and mediator of cardiovascular diseases. However, data are contradictory, and the mechanisms are obscure. Strikingly, the role of the TMAO precursor trimethylamine (TMA) has not drawn attention in cardiovascular studies even though toxic effects of TMA were proposed several decades ago. We assessed plasma TMA and TMAO levels in healthy humans (HH) and cardiovascular patients qualified for aortic valve replacement (CP). The cytotoxicity of TMA and TMAO in rat cardiomyocytes was evaluated using an MTT test. The effects of TMA and TMAO on albumin and lactate dehydrogenase (LDH) were assessed using fluorescence correlation spectroscopy. In comparison to HH, CP had a two-fold higher plasma TMA (p < 0.001) and a trend towards higher plasma TMAO (p = 0.07). In CP plasma, TMA was inversely correlated with an estimated glomerular filtration rate (eGFR, p = 0.002). TMA but not TMAO reduced cardiomyocytes viability. Incubation with TMA but not TMAO resulted in the degradation of the protein structure of LDH and albumin. In conclusion, CP show increased plasma TMA, which is inversely correlated with eGFR. TMA but not TMAO exerts negative effects on cardiomyocytes, likely due to its disturbing effect on proteins. Therefore, TMA but not TMAO may be a toxin and a marker of cardiovascular risk.

Behavioural and physiological assessment of stress reactions during vaginal examination in dairy cows

Objectives and aim: The objective of this study was to determine the origin of an arched back in cows during vaginal examination. Moreover, we tested whether the duration of an arched back and avoidance reactions during vaginal examination can be decreased by epidural anaesthesia or analgesic treatment. Material and methods: Behaviour during cleaning of the perivaginal region and during vaginal examination was scored using the avoidance reactivity score (ARS). Heart rate (HR) was recorded in 10 dairy cows considering four experimental phases, i.e. baseline, cleaning the perivaginal region, vaginal examination and post-examination. Each cow was examined three times and received no treatment (CON), an epidural anaesthesia (EPID) or an analgesic treatment (NSAID). The duration of an arched back during and post-examination was measured. Results: The expression of the arched back was shortest in cows of group EPID and longest in cows of group CON. Avoidance reactions did not differ between the cleaning phase and vaginal examination in cows of group EPID. Cows of group CON showed the strongest avoidance reactions during examination, whereas cows of group EPID showed least avoidance reactions. Mean HR increased during cleaning and vaginal examination and decreased post-examination. Mean HR during vaginal examination did not differ between treatment groups. Conclusion: The results show that cows express discomfort during vaginal examination with an increase in avoidance reactions and HR. Although epidural anaesthesia could reduce sensitivity in the perivaginal region, cows still felt the urge to empty the vagina from the examiner’s hand and, thus, were arching their back. Clinical relevance: In practice, routine vaginal examinations in dairy cows have not been considered as invasive examinations. Our results show that vaginal examinations indeed do cause discomfort. We do not suggest the application of any anaesthetic treatment as appropriate before routine vaginal examinations. None theless, the examiner should be aware of the stress potential of vaginal examinations and conduct such examinations most carefully.

Behavioural and physiological assessment of stress reactions during vaginal examination in dairy cows

OBJECTIVES AND AIM

The objective of this study was to determine the origin of an arched back in cows during vaginal examination. Moreover, we tested whether the duration of an arched back and avoidance reactions during vaginal examination can be decreased by epidural anaesthesia or analgesic treatment.

MATERIAL AND METHODS

Behaviour during cleaning of the perivaginal region and during vaginal examination was scored using the avoidance reactivity score (ARS). Heart rate (HR) was recorded in 10 dairy cows considering four experimental phases, i.e. baseline, cleaning the perivaginal region, vaginal examination and post-examination. Each cow was examined three times and received no treatment (CON), an epidural anaesthesia (EPID) or an analgesic treatment (NSAID). The duration of an arched back during and post-examination was measured.

RESULTS

The expression of the arched back was shortest in cows of group EPID and longest in cows of group CON. Avoidance reactions did not differ between the cleaning phase and vaginal examination in cows of group EPID. Cows of group CON showed the strongest avoidance reactions during examination, whereas cows of group EPID showed least avoidance reactions. Mean HR increased during cleaning and vaginal examination and decreased post-examination. Mean HR during vaginal examination did not differ between treatment groups.

CONCLUSION

The results show that cows express discomfort during vaginal examination with an increase in avoidance reactions and HR. Although epidural anaesthesia could reduce sensitivity in the perivaginal region, cows still felt the urge to empty the vagina from the examiner's hand and, thus, were arching their back.

CLINICAL RELEVANCE

In practice, routine vaginal examinations in dairy cows have not been considered as invasive examina- tions. Our results show that vaginal examinations indeed do cause discomfort. We do not suggest the application of any anaesthetic treatment as appropriate before routine vaginal examinations. Nonetheless, the examiner should be aware of the stress potential of vaginal examinations and conduct such examinations most carefully.

Effects of selenium coating of orthopaedic implant surfaces on bacterial adherence and osteoblastic cell growth

The aim of this study was to evaluate whether coating titanium discs with selenium in the form of sodium selenite decreased bacterial adhesion of Staphylococcus aureus and Staph. epidermidis and impeded osteoblastic cell growth. In order to evaluate bacterial adhesion, sterile titanium discs were coated with increasing concentrations of selenium and incubated with bacterial solutions of Staph. aureus (ATCC 29213) and Staph. epidermidis (DSM 3269) and stained with Safranin-O. The effect of selenium on osteoblastic cell growth was also observed. The adherence of MG-63 cells on the coated discs was detected by staining with Safranin-O. The proportion of covered area was calculated with imaging software. The tested Staph. aureus strain showed a significantly reduced attachment on titanium discs with 0.5% (p = 0.011) and 0.2% (p = 0.02) selenium coating. Our test strain from Staph. epidermidis showed a highly significant reduction in bacterial adherence on discs coated with 0.5% (p = 0.0099) and 0.2% (p = 0.002) selenium solution. There was no inhibitory effect of the selenium coating on the osteoblastic cell growth. Selenium coating is a promising method to reduce bacterial attachment on prosthetic material.

Matrix-associated autologous chondrocyte transplantation in a compartmentalized early stage of osteoarthritis

OBJECTIVE

Cartilage restoration in joints with an early stage of osteoarthritis (OA) is an important clinical challenge. In this study, a compartmentalized, early-stage OA was generated surgically in sheep stifle joints, and this model was used to evaluate a matrix-associated cell transplantation approach for cartilage repair.

METHOD

Eighteen sheep were operated twice. During the first operation, a unicompartmental OA in a stable joint was induced by creating a critical-size defect. The second operation served as a regeneration procedure. The eighteen sheep were divided into three groups. One group was treated with spongialization (SPONGIO), while the two others had spongialization followed by implantation of a hyaluronan matrix with (MACT) or without chondrocytes (MATRIX). The follow-up took place 4 months after the second operation. Gross Assessment of Joint Changes score and Brittberg score were used for the macroscopic evaluation, Mankin score, O'Driscoll score, and immunohistochemistry for collagen type I and type II for histological evaluation.

RESULTS

The MACT group achieved significantly better results in both macroscopic and histological examinations. In the regeneration area, a Mankin score of 7.88 (6.20; 9.55) [mean (upper 95% confidence interval; lower 95% confidence interval)] was reached in the MACT group, 10.38 (8.03; 12.72) in the MATRIX group, and 10.33 (8.80; 11.87) in the SPONGIO group. The O'Driscoll score revealed a highly significant difference in the degree of defect repair: 15.92 (14.58; 17.25) for the MACT group compared to the two other groups [5.04 (1.21; 8.87) MATRIX and 6.58 (5.17; 8.00) SPONGIO; P < 0.0001].

CONCLUSION

This study demonstrates promising results toward the development of a biological regeneration technique for early-stage OA.

[Efficacy of vaginal progesterone inserts (CIDR) to reduce early embryonic losses in dairy cows]

The OBJECTIVE of this study was to test the efficacy of a progesterone releasing device (CIDR®, Pfizer, Germany) inserted on day (d) 20 post insemination (p.i.) to reduce embryonic losses between d 27 and 39 p.i. Furthermore, we hypothesized that CIDR® increases blood progesterone levels during the application period, but does not affect the maintenance of pregnancy after removal.

MATERIAL AND METHODS

The study was conducted on a commercial dairy farm, randomly allocating 74 Holstein Friesian cows to one of two groups. These cows were non-pregnant after previous artificial insemination and treated with an Ovsynch protocol. Group 1 (n=36) received a CIDR® on d 20 p.i. (CIDR® group) while group 2 (n=38) remained untreated (control group). CIDR® was removed on d 39 p.i. Blood samples were drawn from all cows on d 20, 27, 39 and 55 p.i. for analysis of progesterone (P4) concentrations by immunoassay (ADVIA Centaur®, Siemens, Germany). Pregnancy diagnosis was conducted on d 27 p.i. with ultrasonography, and on d 39 and 55 p.i. by transrectal palpation.

RESULTS

The overall prevalence rate of early embryonic losses between d 27 and 39 p.i. was 37.1% (CIDR® group 35.3%, control group 38.9%; p=0.83). On d 39 p.i. 30.5% of all cows were pregnant and the percentage of pregnant cows did not differ between the study groups (p=0.83). Progesterone levels on d 20 p.i. did not differ among cows which were pregnant on d 39 p.i. (p=0.57). On d 27 p.i. progesterone levels in pregnant cows were higher in the CIDR® group (16.2 ± 9.9 ng/ml) compared to the control group (11.2 ± 3.4 ng/ml; p=0.04). Progesterone concentrations were lower on d 39 p.i., but still differed between study groups (p=0.05). After removal of CIDR®, blood progesterone levels did not differ between pregnant cows of both study groups on d 55 p.i. (p=0.36).

CONCLUSION

The application of a progesterone releasing device led to increased blood progesterone levels during the application period, but did not affect maintenance of pregnancy after its removal.

CLINICAL RELEVANCE

Supplementation with progesterone at d 20 p.i. does not decrease early embryonic losses between d 27 and 39 p.i. or increase the number of cows pregnant on d 39 p.i.

Wirksamkeit einer vaginalen Progesteronspange zur Verringerung embryonaler Verluste in der Frühträchtigkeit bei Milchkühen

Ziel der Studie war, den Einfluss einer intravaginalen Progesteronspange (CIDR®, Pfizer) auf embryonale Verluste zwischen Tag 27 und 39 post inseminationem (p. i.) zu testen. Geprüft wurden ferner die Hypothesen, dass die Progesteronspange die Serum-Progesteronkonzentration während der Anwendung beeinflusst und sich nach ihrer Entfernung keine negativen Auswirkungen auf das Fortbestehen der Trächtigkeit ergeben. Material und Methoden: Bei 74 Kühen eines Milchviehbetriebs in Brandenburg erfolgte eine zufällige Zuordnung zu zwei Gruppen. Diese Tiere waren nach Besamung als nichttragend diagnostiziert worden und wurden daraufhin hormonell in einem Ovsynch-Programm behandelt und terminiert besamt. Kühe der CIDR®-Gruppe (n = 36) erhielten an Tag 20 p. i. eine Progesteronspange, die an Tag 39 p. i. entfernt wurde. Kühe der Kontrollgruppe (n = 38) blieben unbehandelt. Blutproben zur Messung der Progesteronkonzentration mittels Immunoassay wurden an den Tagen 20, 27, 39 und 55 p. i. entnommen. Trächtigkeitsuntersuchungen fanden an Tag 27 p. i. mittels Ultraschall und an den Tagen 39 und 55 p. i. mittels rektaler Palpation statt. Ergebnisse: Die embryonalen Verluste zwischen Tag 27 und 39 p. i. betrugen insgesamt 37,1% (CIDR®-Gruppe: 35,3%; Kontrollgruppe: 38,9%; p = 0,83). Die Progesteronkonzentrationen unterschieden sich an Tag 20 p. i. zwischen den an Tag 39 p. i. trächtigen Tieren beider Gruppen nicht. An Tag 27 p. i. lag die Konzentration in der CIDR®-Gruppe mit 16,2 ± 9,9 ng/ ml höher als in der Kontrollgruppe mit 11,2 ± 3,4 ng/ml (p = 0,04). Nach Präparatentfernung zeigten Kühe der CIDR®-Gruppe an Tag 55 p. i. keine höheren Progesteronwerte als Kontrolltiere. Schlussfolgerung: Die Progesteronspange steigerte die Progesteron konzentration während der Anwendung und ihre Entfernung hatte keinen negativen Einfluss auf das Fortbestehen der Trächtigkeit . Klinische Relevanz: Die Supplementierung mit Progesteron an Tag 20 p. i. kann die embryonalen Verluste zwischen Tag 27 und 39 p. i. nicht verringern oder den Anteil tragender Tiere erhöhen.

Biocompatibility and surface structure of chemically modified immunoisolating alginate‐PLL capsules

Grafting of encapsulated living cells has the potential to cure a wide variety of diseases. Large-scale application of the technique, however, is hampered by insufficient biocompatibility of the capsules. A major factor in the biocompatibility of capsules is inadequate covering of the inflammatory poly-L-lysine (PLL) on the capsules' surface. In the present study, we investigate whether tissue responses against alginate-PLL capsules can be reduced by crosslinking the surface of the capsules with heparin or polyacrylic acid. Our transplant study in rats shows a tissue response composed of fibroblasts and macrophages on alginate-PLL-alginate and alginate-PLL-heparin capsules that was completely absent on alginate-PLL-polyacrylic acid capsules. Atomic force microscopy analyses of the capsules demonstrates that the improved biocompatibility of alginate-PLL-capsules by polyacrylic acid coating should not only be explained by a more adequate binding of PLL but also by the induction of a smoother surface. This study shows for the first time that biologic responses against capsules can be successfully deleted by chemically crosslinking biocompatible molecules on the surface of alginate-PLL capsules.

Modulation of macrophage hyperactivity improves survival in a burn-sepsis model

Macrophage hyperactivity with increased production of tumor necrosis factor, interleukin 6, interleukin 1, and prostaglandins has been demonstrated in the injured patient, but the effect of this on the clinical outcome is unclear. We studied the effect of combination interleukin 1 beta and indomethacin sodium therapy on macrophage hyperactivity and survival after sepsis in a murine burn model. Macrophage interleukin 1, interleukin 6, and tumor necrosis factor alpha production were all significantly increased 10 days after thermal injury. Treatment with recombinant human interleukin 1 beta in combination with indomethacin significantly reduced this overproduction of cytokines to normal levels, and this was associated with an improvement in survival after septic challenge (52% survival in interleukin 1 beta-indomethacin-treated group compared with 22% in burned vehicle control mice). Burned mice that received either interleukin 1 beta or indomethacin alone demonstrated tumor necrosis factor and interleukin 6 production and survival intermediate between the interleukin 1 beta-indomethacin-treated group and the vehicle control group. Control of macrophage hyperactivity is associated with improved survival from subsequent sepsis and offers a potential new strategy for the treatment of immune dysfunction in thermally injured patients.