LMP-01/02/01N
In vitro cardiac perfusion system with working heart option, Langendorff, Janiczky and Neely
The LMP-01/02/01N In vitro cardiac perfusion system is characterised by a high degree of modularity, which increases the application possibilities, and its space requirements are very favourable.
- The device is suitable for the examination of isolated hearts from mice, rats, guinea pigs and rabbits.
- The system temperature stability measured directly at the heart connection is within 0.1° C.
- The easy mounting of the preparation on the heart holder is provided by the design of the mobile heart chamber and the heart holder cannula for the species in use.
- The advantage of pump control is the constant flow or constant pressure mode can be achieved with the same device.
- The pressure and temperature sensors are located directly at the heart.
- The Janiczky balloon working heart measurement option is included as standard.
- Neely working heart measurement with replacement of glass and heart holders.
- Dimensions: width: 600 mm, length: 800 mm, height: 850 mm.
Optional:
- We provide the possibility to stimulate the preparation.
- Extra/Intra-cellular MAP measurement is available.
- Pressure, temperature, Map integrated amplifier.
LMP-01 one-column and LMP-02 two-column Langendorff system
- The photo above shows the LMP-01 single-column configuration and the LMP-1/02 system design. Crucially for modularity, the left rack interface is always the Langendorff configuration, and the right interface can be configured by user choice for two-column (LNP-02) or Neely working heart LMP-01N applications. The LMP-01/02 systems have the Janicky (a. balloon) working heart option as standard.
- The advantage of the two-column version is that you can test two substances (agonist/antagonist, agonist/agonist) in the same experiment on the same preparation.
- Another advantage over gravity systems is that, while retaining their positive features, they require less space, and the pump control ensures constant flow at constant pressure. Better heat retention, gas (carbogen) enrichment and cleaning/maintenance are essential for the operation.
In the following, the main components of the system are presented in order of priority of their functionality, based on the overall Figure I.
- Organ holder (a.) with interchangeable cannula (see Figures 1, 2, 2a). The design was aimed at allowing the specimen to be placed on the heart holder cannula as quickly as possible and without damage. To this end, the cannula end was notched to facilitate stability of placement and positioning of the fixation thread. In addition, the cannula is available in Ø4.5, Ø3, Ø2, Ø0.9mm sizes to accommodate body weight and species (see Figure 1).
- One of the most significant advantages of our designed organ holder is that the measuring points and the material inlet channel are located directly above the preparation with minimal blind spots (see Figures 2, 2a).
Ensuring the temperature and pressure inside the system for optimal functioning of the heart preparation
- To ensure optimum temperature stability and pressure, the temperature and pressure of the solution for physiological function are measured directly above the heart preparation in the organ holder. The temperature of the circulating water bath fluid and the baseline value of the pump controlled by the pressure regulator are adjusted in relation to these measured values, both considering the hysteresis of the system.
- To achieve thermal stability of the system, compensate for heat losses that affect hysteresis. These losses are created by the circulating piping system that holds the heat of the system (see 1, 2 Flowchart blue line). Minimizing these losses is aided by the external fluid storage space that returns heat per unit (a. b.).
Circulation of a physiological solution (Krebs), gas input (carbogen) into the system
- The vital part of the system is the valves, through which the physiological solution (Krebs) can be continuously delivered to the heart preparation in adjustable quantities. Our company has designed a multi-position, high-quality and long-lasting valve for this task. The essence of the design is that the combination of the tap material allows a gap-free closure with a good adhesive surface and does not impede the closing/opening direction. Furthermore, unlike other valves in use, it is not a two-position (open/close) valve, but a continuous closing valve.
- A sufficient quantity and quality of carbogen gas, well distributed in the solution, is essential for the proper quality operation of the preparation. To achieve the right dispersion, our company has developed a gas atomizer and fine adjustment device.
- The gas flowing out through the cylinder’s reducer is collected in a windsock and from there the carbogen gas is introduced into the solution by aerifying through a cylindrical clamp – through a tube with a suitable wall thickness.
LMP-01N Working Heart option according to Neely
The modular advantage of the system is further enhanced by the fact that the Neely working heart option can be cost-effectively and technically easily constructed by replacing the glass elements on the left side of the rack. The process flow diagram above illustrates the Working Heart model in principle. The one on the right shows the system developed based on this conceptual arrangement.
The advantage of using the Neely working heart model over the Langendorff method, as shown in the figures, is that it models blood flow under in vitro conditions, creating a much more physiological mode of operation.
In the model, the perfusion solution (e.g. Krebs) enters the left atrium via the pulmonary vein and is pumped out through the left ventricle and aorta against a resistance, thus modelling the systemic vascular resistance of the body. Furthermore, this design allows the heart to produce a physiological pumping action under in vitro conditions.
A fundamental requirement for the system was to maintain the optimal physiological state of the preparation (heart) during prolonged operation. Taking this condition into account, the mechanical and glass engineering units were designed and connected to the operation.
- Attach the preparation (heart) to the organ holder in the shortest time and without damage.
- Ensure thermal stability of the system.
- Ensure adequate gas supply and unobstructed flow of perfusion solution.
- Smooth transition between two perfusion modes (Langendorff, Neely).
- Detection of parameters (TH, LVP, AOP) within the preparation and at the connection.
- The continuous Retrograde/Antegrade perfusion of the model is provided by the Langendorff and Working heart modules described above. The two modules are connected by a continuous adjustment valve that does not affect the flow.
- The Working heart module consists of three main units. Each unit consists of double-walled glass reservoir for temperature stability. The elements and the units are connected by silicone tubes. Perfusion is provided by a peristaltic pump.
- Heart holder/organ chamber unit.
- Aorta unit.
- Atrium unit.
- The working heart is illustrated by the yellow line and arrows showing the flow of perfusion solution. This illustration clarifies the relationship between the modules, units and the elements within them.
1. Heart holder/organ chamber unit
The figures above illustrate one of the most integrated units of the system, which consists of three elements. The aim is to fix the preparation quickly and with the least damage and to ensure stable physiological conditions.
- Heart chamber: The cannula design simplifies and accelerates the placement of the preparation. LVP, AOP pressure and Temperature sensing are implemented here. Cannulas are located in a thermostated space. Of particular importance is the fact that the sensing (pressure, temperature) is almost completely blind spot-free. The total system temperature can be controlled to this point.
- Adjustable heart chamber: The chamber holder is fixed to the central rack by a rod. The heart chamber, fixed in the holder, can be moved on the rod.
- Organ chamber: A double-walled glass reservoir closed at the bottom by a two-position tap.
The double wall ensures thermal stability.
Aorta unit
The figure illustrates the elements of the unit and the process of perfusion after completion of the Langendorff module.
Atrium unit
Figure illustrates the elements of the unit and the process of retrograde perfusion.
Eight-point extra cellular MAP sensor
The 8-point non-invasive measurement is a unique development of our company. The preparation is placed in a physiological solution in the organ dish and surrounded by a specially designed MAP sensor. The MAP waves of the preparation are detected by the sensors through the solution. The sensors can be fitted to any standard extracellular force input.
Additional service: mechanical attachment of a stimulating electrode can be provided on request.
Optional accessories
CWB-20
20l circulating water bath
HC-B
Pressure and temperature meter
Stimulating electrode
PC-B
Pump controller
Recommended MAP amplifiers for extra cellular signal processing
We can recommend systems that can be used to amplify physiological MAP signals:
- AD Instruments: Power Lab,
- Bio Pack,
- MSB-MET: Isosys,
- iWorx: LabScribe.
Recommended software
We recommend the following software/hardware systems for the display, storage and analysis of the curves of the measured physiological parameters:
- AD Instruments: Power Lab,
- Bio Pack,
- MSB-MET: Isosys,
- iWorx: LabScribe.
| TECHNICAL FEATURES | LMP-01/02/01N |
|---|---|
| Application | In-vitro heart perfusion working heart system according to Langendorff, Janiczky and Neely |
| Testable organ types | Mouse, rat, guinea pig, rabbit isolated heart |
| Easy to switch between Langendorff and working heart modes during measurement |  |
| Easy mounting of the preparation on the heart holder | |
| Organ holder with stimulation | Space or point stimulation with electrodes |
| Mobile heart reservoir and heart holder cannula | |
| Pressure and temperature sensors located directly at the heart | |
| Gas pre-storage | |
| Gas fine control system | |
| Janiczky balloon working heart measurement | |
| Replacement of glass and heart support with working heart measurement according to Neely | |
| Constant flow or constant pressure mode with pump control | |
| Temperature stability directly at the heart connection 0,1C° | |
| Dimension | 600×800×850mm |
| Vibration-proof stand | |
| Weight | 10kg |
| Thermostation (Optional) | CWB-20 External thermostat: 20l capacity, 30l/min. delivery rate, 0,1C° accuracy |
| Stimulating electrode (Optional) | |
| Pressure and temperature meter (Optional) | HC-B |
| Extra/Intra-cellular MAP measurement (Optional) | EXT-04 |
| Pressure flow regulator (Optional) | PC |
| TECHNICAL FEATURES | CWB-20 thermostat |
|---|---|
| Application | Circulation water bath thermostat |
| Temperature display | LED number display 3 digit |
| Temperature sensor | Semiconductor |
| Temperature control | Automatically with comparator on/off switching |
| Temperature setting | Analogue mode continuous |
| Pump delivery capacity | Maximum 30l/min |
| Working temperature range | Room temperature … +40°C |
| Temperature stability | ±0,01°C |
| Maximum capacity of the tank | 20l |
| Power input | 1300W |
| Dimension | 320×350×220mm |
| Weight | 10kg (without liquid) |
| Power supply | On request: 110V or 220V, 50/60 Hz |
| TECHNICAL FEATURES | PC-B |
|---|---|
| Application | Peristaltic pump contoller |
| Pressure input resistance | 10k Ω |
| Pressure meter calibration | 1V = 100Hgmm |
| Regulation type | PI |
| Regulator output range | 0 … 5V 0 = 0 … 100% |
| Pump on/off control output | |
| Set desired pressure value | |
| Weight | 1kg |
| Power supply | On request: 110V or 220V, 50/60 Hz |
| TECHNICAL FEATURES | HG-B |
|---|---|
| Application | Two-channel pressure and temperature meter |
| HG Amplification | 10 000, continuously adjustable |
| HG Bandwidth | DC, 200Hz* |
| HG Calibration levels | GND, 1V |
| HG Bridge voltage | On demand |
| HG Offset | ±1V (100Hgmm) relative to output |
| HG Display | LED band |
| HG Input impedance | 10MΩ symmetric |
| HG Output impedance | 100Ω asymmetric |
| HG Value conversion | 100Hgmm = 1V |
| TH Bandwidth | DC, 5Hz* |
| TH Calibration levels | GND, 45°C (450mV) |
| TH Bridge amplification | On demand |
| TH Display | LED number display 3 digits |
| TH Input impedance | 10kΩ symmetric |
| TH Output impedance | 100Ω asymmetric |
| TH Sensor type | PT1000 |
| TH value conversion | 10°C = 0.1V |
| Temperature accuracy | ±0,1°C |
| Power supply | On request: 110V or 220V, 50/60 Hz |
| *HG = pressure meter, TH temperature meter |
| TECHNICAL FEATURES | Stimulating electrodes |
|---|---|
| Application | Ventricular stimulating electrode |
| Fixation with manipulators | |
| Maximum voltage | 150V |
| Shaded cable | |
| Diameter | 2mm |
| Length | 150mm |
| Weight | 220g |
| Wire length | 500mm |
| Weight | 200g |
PURCHASING OPPORTUNITIES
- LMP-01/02/01N system
- LMP-01/02/01N system + CWB-20 thermostat
- LMP-01/02/01N system + CWB-20 thermostat + HG-B pressure and temperature meter
- LMP-01/02/01N system + CWB-20 thermostat + HG-B pressure and temperature meter + PC-B pump controller
- LMP-01/02/01N system + CWB-20 thermostat + HG-B pressure and temperature meter + PC-B pump controller + MAP amplifier
- LMP-01/02/01N system + CWB-20 thermostat + HG-B pressure and temperature meter + PC-B pump controller + MAP amplifier + Software
