FIRST
      ADDENDUM TO 

    LETTER
      AGREEMENT

     

    This
      First Addendum to Letter Agreement (“Addendum”) is an addendum to the Letter
      Agreement dated June 3, 2005 (“Agreement”) between the Cytomedix, Inc.
      (“Company”) and Andrew S. Maslan. Except as specifically set forth below, the
      Agreement remains unmodified and upon execution by both parties, this Addendum
      incorporates by reference all provisions of the Agreement not expressly modified
      or specifically deleted herein.

     

    Position:
      Mr. Maslan shall be employed as Chief Financial Officer. In such capacity,
      Mr. Maslan shall report to the Company’s Chief Executive Officer and shall
      have such reporting relationships to the Audit Committee and the Board of
      Directors as are required by regulations applicable to the Company. He shall
      have the powers, responsibilities, restrictions and authorities as are assigned
      to him by the Chief Executive Officer or the Board of Directors. Mr. Maslan
      shall devote his full working time and efforts to the best of his ability,
      experience and talent to the performance of services, duties and
      responsibilities as the Company’s Chief Financial Officer.

     

    Employment
      at Will:
      Mr. Maslan’s employment shall not be for any specific term and may be
      terminated by the Company at any time with or without “cause” as such term is
      defined in Exhibit B to the Agreement. If the Company, in its sole initiative
      and discretion, terminates Mr. Maslan’s employment without cause,
      Mr. Maslan shall be entitled to a six month severance package as follows:
      For a period of six months, Mr. Maslan will continue to receive his annual
      base salary and all other benefits on the same terms and schedules as existed
      immediately prior to his termination and for which he could continue to be
      eligible during that period, based on the governing terms and conditions of
      the
      benefits. . Options awarded will continue to vest during the six month period
      in
      accordance with applicable vesting schedules. Should Mr. Maslan wish to
      terminate his employment, he shall give the Company sixty days
      notice.

     

    Salary
      and Benefits:
      Mr. Maslan shall receive a base salary of $155,000 beginning on
      July 1, 2006. This annual base salary is subject to annual review by the
      Compensation Committee for recommended potential increase each year. Any
      increase in base salary shall constitute base salary under the
      Agreement.

     

    Stock
      Options:
      Upon
      recommendation by the Compensation Committee and approval by the Board of
      Directors, Mr. Maslan shall receive additional options under the Company’s
      Long Term Incentive Plan to purchase 50,000 shares of the Company’s common stock
      at an exercise price equal to the closing sale price of the common stock on
      the
      date the Board of Directors approves the award. The options shall vest as
      follows:


    
      
        	 	 	 	 	 
	
                                  

              	
                Number of Options

              	
                     

              	
                Vesting
                  Date

              	
                                   

              
	 	 	 	 	 
	 	
                16,667

              	 	
                Twelve
                  months from the date the Board of Directors approves the
                  award.

              	 
	 	
                16,667

              	 	
                Twenty-four
                  months from the date the Board of Directors approves the
                  award.

              	 
	 	
                16,666

              	 	
                Thirty-six
                  months from the date the Board of Directors approves the award.
                  

              	 


      

    

     

    Notwithstanding
      the above, the options shall vest immediately upon the termination of
      Mr. Maslan’s employment in connection with a change in control as such
      terms are defined in Exhibit B to the Agreement.

     

    The
      other
      terms and conditions of the options shall be governed by the terms of a stock
      option award agreement in form substantially similar to that presently used
      by
      the Company.

     

    Annual
      Bonus:
      Mr. Maslan shall be eligible for an annual target bonus of twenty-five
      percent (25%) of his earned salary, which may be payable in the form of cash,
      or
      by mutual agreement, in the form of stock options or a combination thereof.
      The
      annual bonus shall be contingent upon Mr. Maslan’s satisfaction of mutually
      agreed upon performance criteria and may be larger or smaller depending upon
      his
      performance. Any awards pursuant to an annual bonus plan shall be governed
      by
      the terms and conditions contained in the grant notice and stock option
      agreement issued to you by the Company.

     

    Acceptance:
      By their
      signature below, the Company and Mr. Maslan agree that the Agreement,
      including Exhibits A and B, as modified by this Addendum, shall be binding
      upon
      and inure to the benefit of Mr. Maslan’s heirs and representatives and the
      assigns and successors of the Company, but neither the Agreement as modified
      by
      this Addendum, nor any rights or obligations hereunder shall be assignable
      or
      otherwise subject to hypothecation by Mr. Maslan or by the Company, except
      that the Company may assign the Agreement to any successor (whether by merger,
      purchase or otherwise) to the stock, assets or business(es) of the Company.
      

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

     

    EXECUTED
      AS OF October 4, 2006.

     

    
      	 	
              CYTOMEDIX,
                INC.

            
	 	 	 
	 	
              By: 

            	
              /s/
                Kshitij Mohan

            
	 	 	
              Kshitij
                Mohan, Ph.D.

              Chief
                Executive Officer

            
	 	 
	 	 	 
	 	
              By: 

            	
              /s/
                Andrew S. Maslan

            
	 	 	
              Mr. Andrew
                S. Maslan