Screening of Self-Assembling of Collagen IV Fragments into Stable Structures Potentially Useful in Regenerative Medicine

The aim of the research was to check whether it is possible to use fragments of type IV collagen to obtain, as a result of self-assembling, stable spatial structures that could be used to prepare new materials useful in regenerative medicine. Collagen IV fragments were obtained by using DMT/NMM/TosO- as a coupling reagent. The ability to self-organize and form stable spatial structures was tested by the CD method and microscopic techniques. Biological studies covered: resazurin assay (cytotoxicity assessment) on BJ, BJ-5TA and C2C12 cell lines; an alkaline version of the comet assay (genotoxicity), Biolegend Legendplex human inflammation panel 1 assay (SC cell lines, assessment of the inflammation activity) and MTT test to determine the cytotoxicity of the porous materials based on collagen IV fragments. It was found that out of the pool of 37 fragments (peptides 1-33 and 2.1-2.4) reconstructing the outer sphere of collagen IV, nine fragments (peptides: 2, 4, 5, 6, 14, 15, 25, 26 and 30), as a result of self-assembling, form structures mimicking the structure of the triple helix of native collagens. The stability of spatial structures formed as a result of self-organization at temperatures of 4 °C, 20 °C, and 40 °C was found. The application of the MST method allowed us to determine the Kd of binding of selected fragments of collagen IV to ITGα1β1. The stability of the spatial structures of selected peptides made it possible to obtain porous materials based on their equimolar mixture. The formation of the porous materials was found for cross-linked structures and the material stabilized only by weak interactions. All tested peptides are non-cytotoxic against all tested cell lines. Selected peptides also showed no genotoxicity and no induction of immune system responses. Research on the use of porous materials based on fragments of type IV collagen, able to form stable spatial structures as scaffolds useful in regenerative medicine, will be continued.

Long-course preoperative chemoradiation versus 5 × 5 Gy and consolidation chemotherapy for clinical T4 and fixed clinical T3 rectal cancer: long-term results of the randomized Polish II study

BACKGROUND

This trial evaluated whether preoperative short-course radiotherapy and consolidation chemotherapy (CCT) were superior to chemoradiation in rectal cancers with clinical (c)T4 or fixed cT3. Previously, we reported early results showing no differences in the radical surgery rate (primary end point). In the short-course/CCT group, we observed lower acute toxicity of preoperative treatment and better overall survival (OS). We updated results to determine whether the benefit in OS was sustained and to evaluate late complications.

PATIENTS AND METHODS

Patients with cT4 or fixed cT3 rectal cancer were randomized either to preoperative 5 × 5 Gy and three cycles of FOLFOX4 or to chemoradiation (50.4 Gy with bolus 5-Fu, leucovorin and oxaliplatin).

RESULTS

Patients (N = 515) were eligible for analysis, 261 in the short-course/CCT group and 254 in the chemoradiation group. The median follow-up was 7.0 years. The difference in OS was insignificant [hazard ratio (HR) 0.90; 95% confidence interval (CI) 0.70-1.15; P = 0.38). However, the difference in early OS favouring short-course/CCT previously reported was observed again, being 9% at 3 years (95% CI 0.5% to 17%). This difference disappeared later; at 8 years OS was 49% in both groups. There was no difference in disease-free survival (HR 0.95; 95% CI 0.75-1.19; P = 0.65) at 8 years 43% versus 41% in the short-course/CCT group versus the chemoradiation group, respectively. The corresponding values for cumulative incidences of local failure and distant metastases did not differ and were HR = 1.08, 95% CI 0.70-1.23, P = 0.60, 35% versus 32% and HR = 1.10, 95% CI 0.68-1.23, P = 0.54, 36% versus 34%, respectively. The rate of late complications was similar (P = 0.66), grade 3+ being 11% versus 9% in the short-course/CCT group versus the chemoradiation group, respectively.

CONCLUSION

The superiority of preoperative short-course/CCT over chemoradiation was not demonstrated.

CLINICAL TRIAL NUMBER

The trial is registered as ClinicalTrials.gov number NCT00833131.

Search for New Aggregable Fragments of Human Insulin

In this study, three independent methods were used to identify short fragment of both chains of human insulin which are prone for aggregation. In addition, circular dichroism (CD) research was conducted to understand the progress of aggregation over time. The insulin fragments (deca- and pepta-peptides) were obtained by solid-phase synthesis using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium toluene-4-sulfonate (DMT/NMM/TosO^-) as a coupling reagent. Systematic studies allowed identification of the new fragments, expected to be engaged in triggering aggregation of the entire structure of human insulin under physiological conditions. It was found that the aggregation process occurs through various structural conformers and may favor the formation of a fibrous structure of aggregate.

Modification of Syndiotactic Polypropylene with Nano-Calcium Carbonate and Halloysite

Composites of syndiotactic polypropylene (sPP) with 5 to 17 vol.° of halloysite and 2.5 to 7.5 vol.° of stearic acid modified nano-calcium carbonate, having an average grain size of 80 nm, were prepared and examined. The effect of fillers on thermal properties of sPP was different; halloysite increased markedly peak crystallization temperature. The composites with the highest filler contents, 7.5 vol.° of calcium carbonate and 17 vol.° of halloysite, exhibited a solid-like behavior at 170 °C, with the storage modulus exceeding the loss modulus in the entire frequency range, that is 512 to 0.1 rad s−1. The composites with halloysite exhibited decreased Izod impact strength compared to neat sPP. On the contrary, 2.7 fold improvement of the impact strength was found for the composites with nano-calcium carbonate. Moreover, nano-calcium carbonate did not worsen the drawability of the materials during uniaxial drawing. It was found that debonding at calcium carbonate/sPP interface occurred both during the impact test and tensile drawing facilitating the plastic deformation of the polymer.

Long-course oxaliplatin-based preoperative chemoradiation versus 5 × 5 Gy and consolidation chemotherapy for cT4 or fixed cT3 rectal cancer: results of a randomized phase III study

BACKGROUND

Improvements in local control are required when using preoperative chemoradiation for cT4 or advanced cT3 rectal cancer. There is therefore a need to explore more effective schedules.

PATIENTS AND METHODS

Patients with fixed cT3 or cT4 cancer were randomized either to 5 × 5 Gy and three cycles of FOLFOX4 (group A) or to 50.4 Gy in 28 fractions combined with two 5-day cycles of bolus 5-Fu 325 mg/m(2)/day and leucovorin 20 mg/m(2)/day during the first and fifth week of irradiation along with five infusions of oxaliplatin 50 mg/m(2) once weekly (group B). The protocol was amended in 2012 to allow oxaliplatin to be then foregone in both groups.

RESULTS

Of 541 entered patients, 515 were eligible for analysis; 261 in group A and 254 in group B. Preoperative treatment acute toxicity was lower in group A than group B, P = 0.006; any toxicity being, respectively, 75% versus 83%, grade III-IV 23% versus 21% and toxic deaths 1% versus 3%. R0 resection rates (primary end point) and pathological complete response rates in groups A and B were, respectively, 77% versus 71%, P = 0.07, and 16% versus 12%, P = 0.17. The median follow-up was 35 months. At 3 years, the rates of overall survival and disease-free survival in groups A and B were, respectively, 73% versus 65%, P = 0.046, and 53% versus 52%, P = 0.85, together with the cumulative incidence of local failure and distant metastases being, respectively, 22% versus 21%, P = 0.82, and 30% versus 27%, P = 0.26. Postoperative and late complications rates in group A and group B were, respectively, 29% versus 25%, P = 0.18, and 20% versus 22%, P = 0.54.

CONCLUSIONS

No differences were observed in local efficacy between 5 × 5 Gy with consolidation chemotherapy and long-course chemoradiation. Nevertheless, an improved overall survival and lower acute toxicity favours the 5 × 5 Gy schedule with consolidation chemotherapy.

CLINICAL TRIAL NUMBER

The trial is registered as ClinicalTrials.gov number NCT00833131.

Surgical site infections following short-term radiotherapy and total mesorectal excision: results of a randomized study examining the role of gentamicin collagen implant in rectal cancer surgery

BACKGROUND

Despite the findings of several randomized clinical studies, the role of gentamicin collagen implant (GCI) in rectal cancer surgery is unclear. Local pelvic application of GCI following preoperative radiotherapy and total mesorectal excision (TME) was evaluated to determine the risk of surgical site infections (SSI).

METHODS

In this single-center trial, 176 patients with rectal cancer after preoperative, short-term radiotherapy (5 × 5 Gy) were randomized either to the study group in which GCI was used or in the control group without GCI. Prior to surgery and intraoperatively five patients were excluded from the study. The remaining 171 patients were analyzed; 86 were in the study group and 85 in the control group.

RESULTS

There were no statistically significant differences in the overall rate of early postoperative complications between the study and control group: 25.6 and 34.1 % respectively; p = 0.245, relative risk (RR) 0.750 [95 % confidence interval (CI) 0.471-1.195]. The reoperation rate was similar in both groups: 12.8 versus 9.4 %; p = 0.628; RR 1.359; (95 % CI 0.575-3.212). The total rate of SSI and organ space SSI were 22.2 and 15.8 % without differences between the study and control group. In patients without anastomotic leakage, the risk of organ space SSI was significantly reduced in patients who received GCI: 2.6 versus 13.0 %; p = 0.018.

CONCLUSIONS

Application of GCI in the pelvic cavity after short-term preoperative radiotherapy and TME may reduce the risk of organ space SSI but only in the absence of anastomotic leakage.

Anorectal and sexual functions after preoperative radiotherapy and full-thickness local excision of rectal cancer

AIMS

Local excision with preoperative radiotherapy may be considered as alternative management to abdominal surgery alone for small cT2-3N0 tumours. However, little is known about anorectal and sexual functions after local excision with preoperative radiotherapy. Evaluation of this issue was a secondary aim of our previously published prospective multicentre study.

METHODS

Functional evaluation was based on a questionnaire completed by 44 of 64 eligible disease-free patients treated with preoperative radiotherapy and local excision. Additionally, ex post, these results were confronted with those recorded retrospectively in the control group treated with anterior resection alone (N = 38).

RESULTS

In the preoperative radiotherapy and local excision group, the median number of bowel movements was two per day, incontinence of flatus occurred in 51% of patients, incontinence of loose stool in 46%, clustering of stools in 59%, and urgency in 49%; these symptoms occurred often or very often in 11%-21% of patients. Thirty-eight per cent of patients claimed that their quality of life was affected by anorectal dysfunction. Nineteen per cent of men and 20% of women claimed that the treatment negatively influenced their sexual life. The anorectal functions in the preoperative radiotherapy and local excision group were not much different from that observed in the anterior resection alone group.

CONCLUSIONS

Our study suggests that anorectal functions after preoperative radiotherapy and local excision may be worse than expected and not much different from that recorded after anterior resection alone. It is possible that radiotherapy compromises the functional effects achieved by local excision.

Nicotinamide and its metabolite N-methylnicotinamide increase skin vascular permeability in rats

BACKGROUND

It has been suggested that topically applied nicotinamide and its metabolite N-methylnicotinamide (NMN(+)) might be useful agents for treatment of dermatological disorders such as acne vulgaris and rosacea.

AIM

This study aimed to find out if the mechanism of these therapeutic effects depends on their vascular effects, by investigating if nicotinamide and NMN(+) are able to influence vascular permeability of the vessels in the skin on the back of Wistar rats.

METHODS AND RESULTS

A dose-dependent increase in vascular permeability was seen in rats treated intradermally with nicotinamide and NMN(+). Interestingly, a significantly stronger effect of NMN(+) compared with nicotinamide was evident. Increased vascular permeability in rats treated with 0.5% NMN(+) ointment was seen. Moreover, indomethacin, a cyclo-oxygenase 1 and 2 inhibitor and N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, reduced the observed effects of nicotinamide and NMN(+).

CONCLUSIONS

This study provides direct in vivo evidence that nicotinamide and its metabolite NMN(+) increase skin vascular permeability in rats by a mechanism that may involve NO and prostaglandins.

N-methylnicotinamide inhibits arterial thrombosis in hypertensive rats

There are few findings indicating that nicotinamide may potentially influence intravascular thrombosis. Interestingly, N-methylnicotinamide, one of the metabolites of nicotinamide - could be more potent than its parent compound. In the present study we have investigated the influence of N-methylnicotinamide on arterial thrombosis in normotensive and renovascular hypertensive rats. The contribution of platelets, coagulation and fibrinolytic systems in the mode of N-methylnicotinamide action was also determined. Furthermore, we examined the role of nitric oxide/prostacyclin in the mechanisms of N-methylnicotinamide action. N-methylnicotinamide, but not nicotinamide, administered intravenously into renovascular hypertensive rats developing electrically induced arterial thrombosis caused dose-dependent decrease of thrombus weight, collagen-induced platelet aggregation and plasma antigen/activity of plasminogen activator inhibitor - 1, without changing of occlusion time, routine coagulation parameters and plasma activity of tissue plasminogen activator. Indomethacin - an inhibitor of prostacyclin synthesis, completely abolished the antithrombotic and antiplatelet effect of N-methylnicotinamide, and the plasma level of 6-keto-PGF(1alpha) , prostacyclin metabolite, increased simultaneously with the inhibition of thrombus formation. Our study shows that N-methylnicotinamide via production/release of prostacyclin inhibits arterial thrombosis development. The antithrombotic effect of N-methylnicotinamide is accompanied by platelet inhibition and enhanced fibrinolysis, due to the decrease production of plasminogen activator inhibitor - 1.

Screening spring wheat for midge resistance in relation to ferulic acid content

The concentration of ferulic acid (FA), the major phenolic acid in the wheat kernel, was found to differ significantly in the mature grain of six wheat cultivars known to have a range of tolerance to the orange wheat blossom midge (Sitodiplosis mosellana). Differences in FA content were correlated with floret infestation level of the cultivars. The wheat cultivars ranked similarly in FA content at the four locations where they were tested, despite a significant effect of environment. Ferulic acid was synthesized mainly during the early stages of grain filling but at different rates among cultivars. Ferulic acid was concentrated primarily in the shorts and bran fractions in an insoluble-bound form. A high correlation was obtained between FA contents as determined by GLC, fluorometry, UV, and colorimetry. The colorimetric procedure was modified as a qualitative, simple, and rapid test for identifying midge-resistant wheat and evaluated in several field trials. The method should provide a rapid tool in the preliminary screening of experimental lines in the development of midge-resistant wheat cultivars.

Generation means analysis of phenolic compounds in maize grain and susceptibility to maize weevil Sitophilus zeamais infestation

Generations derived from crosses between inbred lines were used to analyze the genetics of hydroxycinnamic acid accumulation in maize grain and susceptibility to infestation by the maize weevil Sitophilus zeamais. There was a significant negative correlation between phenolic content and susceptibility of the grain to weevil infestation, and the estimates of genetic parameters indicate that a close relationship between those two traits exists. Key words: insect resistance, maize, maize weevil, genetics, phenolics.