The state pledges and agrees with the holder of any bonds issued under the Hospital Equipment Loan Act that the state will not alter the rights vested in the council to fulfill the terms of any agreements made with the bondholders or in any way impair the rights or remedies of the holders until the bonds, together with the interest thereon, with interest on any unpaid installments of interest, and all costs and expenses in connection with any action or proceeding by or on behalf of the holders are fully met and discharged. The council is authorized to include this pledge and agreement of the state in any agreement with the holders of the bonds.