Cardioprotective effect of angiotensin (1-7) in experimentally induced heart failure in rats

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic VEGA 2/0158/19, VEGA 2/0002/20; Slovak Research and Development Agency APVV-15-0119, APVV-18-0548

The extracellular matrix (ECM) is a highly dynamic structure that affects the proper functioning of various tissues. ECM is involved in cell signaling, participates in the origin and development of pathology and its positive influence can result in improved disease. The pathophysiology of ECM also affects intercellular communication, which results in various arrhythmias in the heart. In the present work, we focused on the signaling pathways involved in cardiac structural remodeling due to volume overload, and at the same time, we tested the possibilities of the cardioprotective effect of angiotensin (1-7) (Ang (1-7)). As an experimental model of volume overload, we chose the aortocaval fistula (ACF) model, where we focused on the compensatory phase of heart failure. Male, 8 weeks old rats, from the normotensive Hannover Sprague-Dawley (HSD), the hypertensive Ren-2 of transgenic rats (TGR), and transgenic rats expressing the angiotensin (1-7) producing a fusion protein (TGR(A1-7)3292), we operationally created the ACF. 5 weeks after operation, the animals were decapitated and cardiac tissue samples were taken. Right and left ventricular tissue samples were used for biometric, biochemical, and proteomic analyzes. TGR(A1-7)3292 rats had significantly less hypertrophy compared to HSD and TGR after ACF. Hydroxyproline was increased in the TGR ACF group in both ventricles and in the right ventricle it was significantly reduced by Ang (1-7) compared to TGR ACF. In our selected proteins, the group of protein kinases C (PKC) α, δ, ε, matrix metalloproteinase 2 (MMP-2), SMAD2/3, connexin 43 (Cx43) and its phosphorylated form (pCx43) there were changes in protein levels, either due to hypertension after ACF, and in several cases the cardioprotective effect of Ang (1-7) was confirmed. PKCα and PKCδ showed a decrease in the TGR ACF group compared to HSD ACF and a decrease in the TGR(A1-7)3292 ACF group compared to HSD and TGR after ACF in both chambers. MMP-2 activity in the left and right ventricles had a reduced trend in the TGR and TGR(A1-7)3292 groups after ACF compared to HSD ACF. The same change occurred in MMP-2 protein expression in the right ventricle, in contrast to the left ventricle, where no change occurred. In the right ventricle, there was a decrease in SMAD2/3 protein expression in the TGR(A1-7)3292 group of ACF compared to HSD and TGR after ACF. Cx43 and pCx43 showed a very similar trend in both chambers, with an increase in the TGR ACF group versus HSD ACF, and the TGR(A1-7)3292 ACF versus HSD and TGR after ACF. Based on the obtained results, it can be stated that the right ventricle is more significantly affected by ACF and the endogenous production of Ang (1-7) alleviated the changes of the monitored proteins and the remodeling of the ECM caused by volume overload.

Cardiac hypertrophy as a response to volume overload in normotension and hypertension, and possible cardioprotection with angiotensin (1–7)

 

The extracellular matrix (ECM) is a highly dynamic structure that affects the proper functioning of various tissues. ECM is involved in cell signaling, participates in the origin and development of pathology and its positive influence can result in improved disease. The pathophysiology of ECM also affects intercellular communication, which results in various arrhythmias in the heart. In the present work, we focused on the signaling pathways involved in cardiac structural remodeling due to volume overload, and at the same time, we tested the possibilities of the cardioprotective effect of angiotensin (1–7) (Ang (1–7)). As an experimental model of volume overload, we chose the aortocaval fistula (ACF) model, where we focused on the compensatory phase of heart failure. Male, 8 weeks old rats, from the normotensive Hannover Spraque-Dawley (HSD), the hypertensive Ren-2 of transgenic rats (TGR), and transgenic rats expressing the Ang (1–7) producing a fusion protein (TGR(A1–7)3292), we operationally created the ACF. 5 weeks after operation, the animals were decapitated and cardiac tissue samples were taken. The ratio of cardiac weight to tibial length did not show differences between normotensive HSD and hypertensive subjects after ACF, but TGR(A1–7)3292 rats had significantly less hypertrophy compared to HSD and TGR after ACF. Hydroxyproline was increased in the TGR ACF group in both ventricles and in the right ventricle it was significantly reduced by Ang (1–7) compared to TGR ACF. In our selected proteins, the group of protein kinases C (PKC) α, δ, ε, matrix metalloproteinase 2 (MMP-2), SMAD2/3, connexin 43 (Cx43) and its phosphorylated form (pCx43) there were changes in protein levels, either due to hypertension after ACF, and in several cases the cardioprotective effect of Ang (1–7) was confirmed. PKCα and PKCδ showed a decrease in the TGR ACF group compared to HSD ACF and a decrease in the TGR(A1–7)3292 ACF group compared to HSD and TGR after ACF in both chambers. MMP-2 activity in the left and right ventricles had a reduced trend in the TGR and TGR(A1–7)3292 groups after ACF compared to HSD ACF. The same change occurred in MMP-2 protein expression in the right ventricle, in contrast to the left ventricle, where no change occurred. In the right ventricle, there was a decrease in SMAD2/3 protein expression in the TGR(A1–7)3292 group of ACFs compared to HSD and TGR after ACF. HSP70 protein expression was also reduced in both chambers in the (TGR(A1–7)3292) ACF group compared to HSD and TGR after ACF. Cx43 and pCx43 showed a very similar trend in both chambers, with an increase in the TGR ACF group versus HSD ACF, and the TGR(A1–7)3292 ACF versus HSD and TGR after ACF. Based on the obtained results, it can be stated that the right ventricle is more significantly affected by ACF and the endogenous production of Ang (1–7) alleviated the changes of the monitored proteins and the remodeling of the ECM caused by volume overload.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic VEGA 2/0158/19, 2/0002/20Slovak Research and Development Agency APVV 15-0119, APVV-19-0317

Inhibition of RAS components attenuates progression of heart failure and its adverse consequences on myocardial remodeling in both normotensive and hypertensive rats

Rationale and purpose

Prevention or attenuation of heart failure (HF) is persistent task in clinic as well as challenge for progress in research. Both, intercellular connexin-43 (Cx43) channels and extracellular matrix (ECM) exert high impact on heart function. Thus, we aimed to explore whether HF due to volume overload (VO) induces alterations in myocardial Cx43, ECM proteins MMP2, SMAD2/3, TGFβ1 and PKC signaling as well as changes that may be revealed by enzyme histochemistry. Moreover, we tested the impact of treatment suppressing RAS on examined targeted proteins.

Methods

VO-HF was induced in male normotensive Hannover Sprague- Dawley (HSD) and mRen-2 transgenic hypertensive (TGR) rats by creating an aorto-caval fistula (ACF) and heart response was examined 20-weeks later. Sham-rats were compared with non-treated rats with ACF and those treated for 15-weeks with ACEI (trandolapril, 6mg/l, p.o.) or ARB (losartan (200mg/l, p.o.). Left ventricular heart (LV) tissue was analyzed using western blot, zymography and enzyme histochemistry.

Key results

Echocardiography confirmed an increase in cardiac output and a decrease in ejection fraction in both strains of rats. BW was higher in TGR vs HSD and it was not affected by VO. HW and LVW were higher in TGR vs HSD and VO increased both parameters regardless the strain while ACEI>ARB attenuated it. In parallel, myocardial pro-hypertrophic PKCd expression was higher in TGR vs HSD and increased in both strains due to VO while both drugs prevent it. Glycogen phosphorylase and capillary associated 5-nucleotidase, alkaline phospatase and dipeptidyl peptidase IV activities were reduced due to VO in HSD and TGR and it was attenuated by treatment. Cx43 expression and its functional phosphorylation status were lower in TGR vs HSD and suppressed in both strains due to VO but ACEI>ARB prevented it. Similar trend of changes was observed in PKCe expression, which phosphorylates Cx43. Profibrotic TGFβ1-Smad2/3 pathway was suppressed along with reduced MMP2 activity in TGR comparing to HSD. VO reduced SMAD2/3 in HSD and TGFβ1 in TGR as well as MMP2 expression in both strains, whereby treatment abolished these changes. VO decreased MMP2 (63kDa) activity only in TGR and ARB prevented it. VO did not affect collagen deposition in either strain vs sham rats.

Conclusions

Hypertrophic and hypofibrotic phenotypes are induced by volume overload in both rat strains. Together with deterioration of Cx43 mediated intercellular coupling it may contribute to heart dysfunction. Inhibition of RAS components attenuates progression of VO and its adverse consequences.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic VEGA 2/0158/19, 2/0002/20

Cyanoacrylate tissue adhesive in blepharoplasty

This article reports the results of an animal study designed to evaluate the usefulness of butyl 2-cyanoacrylate (Histoacryl) in blepharoplasty skin closure. Bilateral upper and lower lid blepharoplasty skin incisions were made on seven pigs. We compared the wounds closed with 6.0 nylon to those closed with Histoacryl at 1, 2, 4, and 9 weeks postoperatively. The tensile strength of the "glued" incisions was significantly greater than that of the sutured incisions only at the 9-week postoperative interval (p < 0.05). There was no significant difference in bond strength, however, between the two methods at 1, 2 and 4 weeks postoperatively. Histopathologic analyses of sutured and glued wounds were compared at the same designated postoperative periods. No deleterious effects were found in the overall healing of the cutaneous wounds closed with Histoacryl.

Hertel exophthalmometry without orbital rim contact

BACKGROUND

The Hertel exophthalmometer is the most widely used instrument for the measurement of globe malposition, but an absent or damaged lateral orbital rim will preclude its application. To circumvent this shortcoming, the authors have developed a fixation adapter that attaches to a standard Hertel instrument and transfers fixation to the forehead and nasion from the lateral orbit.

METHODS

The adapter design is presented and discussed, along with illustrative clinical cases. A study of 30 healthy patients was performed to assess the validity of the adapter with respect to the Hertel standard. The agreement was then evaluated by comparing the Hertel adapter measurements from each patient with that of the adapter. A Wilcoxon statistic was performed to assess differences in the paired values from each patient for both techniques.

RESULTS

Analysis on a sample (n = 30) of a healthy adult population does not show a statistical difference between the Hertel adapter and the adapter data (P > 0.05). In addition, more than 90% of the differences fall within +/- 1 mm (standard deviation = 1.02 mm) of the means for both eyes, which is within the accepted variance for the Hertel instrument.

CONCLUSION

The new fixation adapter promises to become useful in assessing trauma and surgical cases where the lateral orbital rim has been violated and will expand the application of Hertel exophthalmometry to these situations.

Dacryocystorhinostomy in elderly patients: regional anesthesia without cocaine

Elderly patients with nasolacrimal obstruction who are in poor health often pose a special anesthetic and surgical risk. General anesthesia and the use of cocaine packs may be contraindicated because of potentially dangerous side effects. Regional block dacryocystorhinostomy has gained popularity in all adult patient groups, but specifically it appears to be the procedure of choice in elderly patients. It is well suited for either hospital-based or ambulatory care. We describe our experience with the procedure in 25 consecutive patients (28 procedures), with emphasis on modification of our standard technique to suit regional blockade. Mechanisms of cocaine toxicity in the surgical setting are reviewed, and a method of local anesthesia without cocaine nasal packing is presented.

Tests for contralateral pseudoretraction in blepharoptosis

Pseudoretraction of the contralateral upper eyelid has long been recognized as a clinical phenomenon in certain patients with unilateral ptosis. In this prospective study of 30 patients with ptosis, we used two commonly used tests for pseudoretraction, the digital "lift" and "closure" tests. We also describe two new adaptations, the "lift and release" and "closure and release," which enhance these basic tests. The incidence of pseudoretraction in unilateral ptosis was found to be 66.7% and the test with the highest positive yield was the "closure test" (66.7%). The use of clinical tests for pseudoretraction, including the "release" maneuvers, are recommended as part of routine preoperative assessment of blepharoptosis.

Dog and human bites of the eyelid repaired with retrieved autogenous tissue

Two cases of traumatic avulsion of the upper eyelid were surgically repaired with retrieved autogenous tissue. Both injuries were caused by bites, canine in one case and human in the other. Surgical repair consisted of débridement of the retrieved tissue and layered closure of the wound 17 and 40 hours after the injury occurred. Good functional results were obtained in both cases. In both patients mild lid retraction and loss of cilia were noted. One of the patients underwent a secondary lid-lengthening procedure with scleral grafting for optimal cosmesis.

Modified Tessier flap for reconstruction of the upper eyelid

We present a modification of the Tessier or orbitonasojugal flap for use in upper eyelid reconstruction. It is suitable for repairing full-thickness defects involving 60% or more of the lid margin and has the advantage of being a one-step procedure.

Orbital compartment syndrome. Direct measurement of orbital tissue pressure: 1. Technique

Many disorders of the orbit produce an increase in intraorbital pressure, which may result in the development of an orbital compartment syndrome and visual loss. Traditionally, orbital tension is assessed clinically by indirect means based on retrodisplacement of the globe. The authors describe their experience with the "slit-catheter" technique for direct tissue pressure measurement as applied to the orbit. The preliminary results indicate that normal orbital pressure ranges from 3.0 to 6.0 mm Hg. In patients with Graves' orbitopathy the values ranged from 7.0 to 15.0 mm Hg. The results suggest that the technique may have many exciting possibilities as a clinical research tool in orbital disease, and its use will result in better understanding of orbital compartment syndromes.

Avulsion of the canalicular system

Avulsion of the common canaliculus from its attachment to the lacrimal sac should be suspected in cases involving either deep lacerations on the lateral side of the nose or traumatic telecanthus in midfacial trauma. Blunting of the canalicular angle and rounding of the inner canthus are confirming signs. A canaliculodacryocystorhinostomy can be performed to reanastomize the lacrimal drainage pathways and relieve epiphora.

Effect of extracapsular cataract extraction on intraocular pressure

Intraocular pressure (IOP) was measured in 27 normotensive patients scheduled to undergo uncomplicated extracapsular cataract extraction with insertion of a posterior chamber intraocular lens implant. The measurements were recorded the day before surgery, 3, 6 and 9 hours after surgery and the following morning. Fourteen of the patients had a substantial increase in IOP, to more than 30 mm Hg, on the evening of surgery. Most had normal IOP values the next morning. Ophthalmologists should be aware of this possible effect of extracapsular cataract extraction on IOP.

Stereochronoscopy of the optic disc with stereoscopic cameras

Goldmann's chronoscopy, a form of time-based photogrammetry of the optic disc, can be accomplished by repeated simultaneous stereophotography. The variations in centration and image orientation are nulled by azimuthal rotation and fusion of two pairs of stereophotographs taken at separate times.